The bone matrix plays an indispensable role in the human body,and its unique biomechanical and mechanobiological properties have received much attention.The bone matrix has unique mechanical anisotropy and exhibits bo...The bone matrix plays an indispensable role in the human body,and its unique biomechanical and mechanobiological properties have received much attention.The bone matrix has unique mechanical anisotropy and exhibits both strong toughness and high strength.These mechanical properties are closely associated with human life activities and correspond to the function of bone in the human body.None of the mechanical properties exhibited by the bone matrix is independent of its composition and structure.Studies on the biomechanics of the bone matrix can provide a reference for the preparation of more applicable bone substitute implants,bone biomimetic materials and scaffolds for bone tissue repair in humans,as well as for biomimetic applications in other fields.In providing mechanical support to the human body,bone is constantly exposed to mechanical stimuli.Through the study of the mechanobiology of the bone matrix,the response mechanism of the bone matrix to its surrounding mechanical environment can be elucidated and used for the health maintenance of bone tissue and defect regeneration.This paper summarizes the biomechanical properties of the bone matrix and their biological significance,discusses the compositional and structural basis by which the bone matrix is capable of exhibiting these mechanical properties,and studies the effects of mechanical stimuli,especially fluid shear stress,on the components of the bone matrix,cells and their interactions.The problems that occur with regard to the biomechanics and mechanobiology of the bone matrix and the corresponding challenges that may need to be faced in the future are also described.展开更多
Microneedles(MNs)are an innovative and viable option for drug delivery that offer the distinct advantages of minimal invasiveness,painlessness,stable drug loading,efficient drug permeation,and biocompatibility.MNs wer...Microneedles(MNs)are an innovative and viable option for drug delivery that offer the distinct advantages of minimal invasiveness,painlessness,stable drug loading,efficient drug permeation,and biocompatibility.MNs were first used to penetrate the skin surface and facilitate transcutaneous drug delivery with great success.Recent applications of MNs have extended to non-transdermal drug delivery,specifically,to various tissues and organs.This review captures the fabrication methods for MNs,discusses advanced design strategies for achieving controlled drug release,and summarizes current MN applications in delivering multiple therapeutic agents to the cardiovascular,digestive(e.g.,oral cavity),reproductive,and central nervous systems.The findings in this review would contribute toward the improved designs of MN systems that can be modified according to purpose,including material selection,structural design,choice of fabrication methods,and tissue considerations,to determine the optimal therapeutic regimen for the target treatment area.展开更多
Accurate segmentation of oral surgery-related tissues from cone beam computed tomography(CBCT)images can significantly accelerate treatment planning and improve surgical accuracy.In this paper,we propose a fully autom...Accurate segmentation of oral surgery-related tissues from cone beam computed tomography(CBCT)images can significantly accelerate treatment planning and improve surgical accuracy.In this paper,we propose a fully automated tissue segmentation system for dental implant surgery.Specifically,we propose an image preprocessing method based on data distribution histograms,which can adaptively process CBCT images with different parameters.Based on this,we use the bone segmentation network to obtain the segmentation results of alveolar bone,teeth,and maxillary sinus.We use the tooth and mandibular regions as the ROI regions of tooth segmentation and mandibular nerve tube segmentation to achieve the corresponding tasks.The tooth segmentation results can obtain the order information of the dentition.The corresponding experimental results show that our method can achieve higher segmentation accuracy and efficiency compared to existing methods.Its average Dice scores on the tooth,alveolar bone,maxillary sinus,and mandibular canal segmentation tasks were 96.5%,95.4%,93.6%,and 94.8%,respectively.These results demonstrate that it can accelerate the development of digital dentistry.展开更多
This study aimed to conduct finite element(FE)analysis matched with an in vitro experiment to analyze traumatic retinal detachments(TrRD)resulting from blunt trauma and provide stress and strain thresholds to predict ...This study aimed to conduct finite element(FE)analysis matched with an in vitro experiment to analyze traumatic retinal detachments(TrRD)resulting from blunt trauma and provide stress and strain thresholds to predict the occurrence of TrRD.The in vitro experiment was performed on forty-eight porcine eyes using a pendulum device.We examined dynamic mechanical responses at four energy levels.A FE model,based on experimental results and published data,was used to simulate TrRD.Fifty-one additional eyes underwent immediate pathological examination following blunt impact.A dynamic variation of velocities was observed post-impact,displaying an approximate cosine oscillation-attenuation profile.Energy absorption increased as the initial energy and differed significantly at four energy levels(p<0.001).FE simulation showed a peak strain of 0.462 in the anterior vitreous body and a peak stress of 1.408 MPa at the cornea at the high-energy level.During the energy transfer,the stress was initially observed in retinal region along the impact direction at the separation.TrRD were observed in injured eyes,where a few detachments were detected in control eyes.Correlations were performed between the proportion of pathological outcomes and FE results.In conclusion,this study suggests that stress contributes to the development of retinal detachment,providing an indicator to distinguish the occurrence of TrRD.展开更多
Dear Editor,This letter presents a biocompatible cross-shaped magnetic soft robot and investigates its deformation mode control strategy through COMSOL modeling and simulation.Magnetic soft robots offer novel avenues ...Dear Editor,This letter presents a biocompatible cross-shaped magnetic soft robot and investigates its deformation mode control strategy through COMSOL modeling and simulation.Magnetic soft robots offer novel avenues for precise treatment within intricate regions of the human body.展开更多
Metal corrosion causes significant economic losses,safety issues,and environmental pollution.Hence,its prevention is of immense research interest.Carbon dots(CDs)are a new class of zero-dimensional carbon nanomaterial...Metal corrosion causes significant economic losses,safety issues,and environmental pollution.Hence,its prevention is of immense research interest.Carbon dots(CDs)are a new class of zero-dimensional carbon nanomaterials,which have been considered for corrosion protection applications in recent years due to their corrosion inhibition effect,fluorescence,low toxicity,facile chemical modification,and cost-effectiveness.This study provides a comprehensive overview of the synthesis,physical and chemical properties,and anticorrosion mechanisms of functionalized CDs.First,the corrosion inhibition performance of different types of CDs is introduced,followed by discussion on their application in the development of smart protective coatings with self-healing and/or self-reporting properties.The effective barrier formed by CDs in the coatings can inhibit the spread of local damage and achieve self-healing behavior.In addition,diverse functional groups on CDs can interact with Fe^(3+)and H^(+)ions generated during the corrosion process;this interaction changes their fluorescence,thereby demonstrating self-reporting behavior.Moreover,challenges and prospects for the development of CD-based corrosion protection systems are also presented.展开更多
Cancer cells dysregulate lipid metabolism to accelerate energy production and biomolecule synthesis for rapid growth.Lipid metabolism is highly dynamic and intrinsically heterogeneous at the single cell level.Although...Cancer cells dysregulate lipid metabolism to accelerate energy production and biomolecule synthesis for rapid growth.Lipid metabolism is highly dynamic and intrinsically heterogeneous at the single cell level.Although°uorescence microscopy has been commonly used for cancer research,bulky°uorescent probes can hardly label small lipid molecules without perturbing their biological activities.Such a challenge can be overcome by coherent Raman scattering(CRS)microscopy,which is capable of chemically selective,highly sensitive,submicron resolution and high-speed imaging of lipid molecules in single live cells without any labeling.Recently developed hyperspectral and multiplex CRS microscopy enables quantitative mapping of various lipid metabolites in situ.Further incorporation of CRS microscopy with Raman tags greatly increases molecular selectivity based on the distinct Raman peaks well separated from the endogenous cellular background.Owing to these unique advantages,CRS microscopy sheds new insights into the role of lipid metabolism in cancer development and progression.This review focuses on the latest applications of CRS microscopy in the study of lipid metabolism in cancer.展开更多
3D printing techniques offer an effective method in fabricating complex radially multi-material structures.However,it is challenging for complex and delicate radially multi-material model geometries without supporting...3D printing techniques offer an effective method in fabricating complex radially multi-material structures.However,it is challenging for complex and delicate radially multi-material model geometries without supporting structures,such as tissue vessels and tubular graft,among others.In this work,we tackle these challenges by developing a polar digital light processing technique which uses a rod as the printing platform.The 3D model fabrication is accomplished through line projection.The rotation and translation of the rod are synchronized to project and illuminate the photosensitive material volume.By controlling the distance between the rod and the printing window,we achieved the printing of tubular structures with a minimum wall thickness as thin as 50 micrometers.By controlling the width of fine slits at the printing window,we achieved the printing of structures with a minimum feature size of 10 micrometers.Our process accomplished the fabrication of thin-walled tubular graft structure with a thickness of only 100 micrometers and lengths of several centimeters within a timeframe of just 100 s.Additionally,it enables the printing of axial multi-material structures,thereby achieving adjustable mechanical strength.This method is conducive to rapid customization of tubular grafts and the manufacturing of tubular components in fields such as dentistry,aerospace,and more.展开更多
Background Identification of futile recanalisation following endovascular therapy(EVT)in patients with acute ischaemic stroke is both crucial and challenging.Here,we present a novel risk stratification system based on...Background Identification of futile recanalisation following endovascular therapy(EVT)in patients with acute ischaemic stroke is both crucial and challenging.Here,we present a novel risk stratification system based on hybrid machine learning method for predicting futile recanalisation.Methods Hybrid machine learning models were developed to address six clinical scenarios within the EVT and perioperative management workflow.These models were trained on a prospective database using hybrid feature selection technique to predict futile recanalisation following EVT.The optimal model was validated and compared with existing models and scoring systems in a multicentre prospective cohort to develop a hybrid machine learning-based risk stratification system for futile recanalisation prediction.Results Using a hybrid feature selection approach,we trained and tested multiple classifiers on two independent patient cohorts(n=1122)to develop a hybrid machine learning-based prediction model.The model demonstrated superior discriminative ability compared with other models and scoring systems(area under the curve=0.80,95%CI 0.73 to 0.87)and was transformed into a web application(RESCUE-FR Index)that provides a risk stratification system for individual prediction(accessible online atfr-index.biomind.cn/RESCUE-FR/).Conclusions The proposed hybrid machine learning approach could be used as an individualised risk prediction model to facilitate adherence to clinical practice guidelines and shared decision-making for optimal candidate selection and prognosis assessment in patients undergoing EVT.展开更多
Poly(glycerol-dodecanoate)(PGD)has aroused increasing attention in biomedical engineering for its degradability,shape memory and rubber-like mechanical properties,giving it potential to fabricate intelligent implants ...Poly(glycerol-dodecanoate)(PGD)has aroused increasing attention in biomedical engineering for its degradability,shape memory and rubber-like mechanical properties,giving it potential to fabricate intelligent implants for soft tissues.Adjustable degradation is important for biodegradable implants and is affected by various factors.The mechanical load has been shown to play an important role in regulating polymer degradation in vivo.An in-depth investigation of PGD degradation under mechanical load is essential for adjusting its degradation behavior after implantation,further guiding to regulate degradation behavior of soft tissue implants made by PGD.In vitro degradation of PGD under different compressive and tensile load has proceeded in this study and describes the relationships by empirical equations.Based on the equations,a continuum damage model is designed to simulate surface erosion degradation of PGD under stress through finite element analysis,which provides a protocol for PGD implants with different geometric structures at varied mechanical conditions and provides solutions for predicting in vivo degradation processes,stress distribution during degradation and optimization of the loaded drug release.展开更多
Pelvic fracture is among the most complicated fractures in traumatic orthopedics,with high mortality and morbidity rates.The main difficulty associated with the reduction surgery is significant muscle resistance.It th...Pelvic fracture is among the most complicated fractures in traumatic orthopedics,with high mortality and morbidity rates.The main difficulty associated with the reduction surgery is significant muscle resistance.It then becomes necessary to decrease the reduction force against this strong muscle resistance,for improving surgical safety.Here,we propose a novel traction method for decreasing the reduction force during pelvic reduction,and investigate the performance of the elastic traction method on decreasing the reduction force using experimental tests and simulation-based analyses.From the experimental results,the reduction force decreased by 59.2%when 10 kg of elastic traction was applied.We also establish a musculoskeletal model of the pelvic fracture reduction,for analyzing the muscle resistance and the optimal traction force applied in reduction surgeries.The elastic traction method can counteract the muscle resistance increase in the non-traction direction owing to its flexibility.We conclude that the optimal traction force applied should be in the 10–15 kg range,and recommend adopting a dynamic traction strategy rather than continuous traction in clinical settings.Elastic traction is very promising for various surgeries that require traction,including pelvic reduction.It significantly reduces force,which can significantly reduce the physical exertion of the operating surgeon,the possibility of additional injuries to the operated patient,and promotes robot-assisted reduction surgeries.展开更多
As the quality of life improves,people pay more and more attention to health.They are concerned about the causes of diseases,and seek better treatments.The most common diseases are biomineralized diseases,four differe...As the quality of life improves,people pay more and more attention to health.They are concerned about the causes of diseases,and seek better treatments.The most common diseases are biomineralized diseases,four different kinds of typical examples among which are selected to elaborate their mechanisms and existing treatments.Whether it is tooth and bone in physiological mineralization or cartilage and blood vessel in pathological mineralization,they are all related to matrix vesicle(MV)-mediated biomineralization.MV-mediated biomineralization is the initial stage of biomineralization and the nucleation site mediating collagen mineralization.Definition,composition,biogenesis,and action mechanism of MVs are refined and expounded,especially a novel biomineralization pathway similar to exosome(EX)origin.Four differences are summarized to distinguish MVs and EXs.A series of treatments using MVs to solve biomineralized diseases such as tooth and bone defects,osteoarthritis and atherosclerosis are proposed,and the experimental extraction steps of MVs are summarized.展开更多
Androgenetic alopecia(AGA)is an androgen-mediated alopecia affected by both genes and hormones.Medication is a relatively common treatment.As a new drug delivery method,microneedles(MNs)can effectively break through t...Androgenetic alopecia(AGA)is an androgen-mediated alopecia affected by both genes and hormones.Medication is a relatively common treatment.As a new drug delivery method,microneedles(MNs)can effectively break through the stratum corneum barrier,deliver drugs more efficiently,and achieve better therapeutic effects.In this study,we develop a composite double-layer MN through multi-step casting fabrication using a polydimethylsiloxane mold.The needle tip was fabricated by mixed solution of chitosan and polyvinylpyrrolidone which was loaded with Polygonum multiflorum extract,and the base layer was prepared by mixed solution of polyvinyl alcohol and polyvinylpyrrolidone.In vitro mechanical tests showed that the maximum load of a single tip of the drug-loaded MN was about 3.5 N,which met the mechanical requirements of skin puncture(>1 N).The drug release experiment showed that the MN could achieve gradual drug release.In the animal experiment,pigmentation and hair regrowth occurred earlier in the Polygonum multiflorum-MN(Pm-MN)group than in the other groups,and hair growth finally appeared in almost the entire area.Compared with the AGA model mice,mice in the Pm-MN group achieved an increase in the number and diameter of hair follicles.In conclusion,the Pm-MN is scientific and feasible for treating AGA.展开更多
Alveolar bone augmentation with fixation screws has difficulties such as non-degradable materials that could lead to secondary surgery and insufficient osseointegration due to the subgingival environment in dental pra...Alveolar bone augmentation with fixation screws has difficulties such as non-degradable materials that could lead to secondary surgery and insufficient osseointegration due to the subgingival environment in dental practice.With degradability and a high degree of osteogenesis,Mg alloy is a successful biodegrad-able material for orthopedic applications,and its application in dentistry has made certain progress.How-ever,considering the unique subgingival healing properties of oral implants,there is still a gap between the desired material properties for clinical applications and available materials.Indeed,studies on the use of Mg-based fixation screws for dentistry applications are still rare.In this study,we reported a magnesium alloy with low combined addition of strontium and lanthanum.The mechanical properties,degradation behavior,osteogenesis,and gingival compatibility were systematically investigated for assess-ing its potential application in alveolar bone fixation screws.With the alloying element content restricted to 0.3 wt.%,Mg-Sr-La alloy still exhibited good mechanical properties,with yield tensile and compressive strength twice higher than those of pure Mg.The in vitro degradation rate of this alloy was 0.10 mm y-1,which was slightly slower than high-purity Mg.The indirect and direct cell assay confirmed the elevated osteoblastic differentiation of MC3T3-E1 and migration of HGF-1 cells.Moreover,Mg-Sr-La alloy demon-strated a relatively slow degradation in the maxillary bone of Beagles.A remarkable promotion of the bone-implant contacts and significantly decreased fibrous encapsulation was observed in the subgingival environment,implying superior osseointegration of the experimental alloy than the titanium control.The empirical findings here reveal the great potential of Mg-Sr-La alloy for the application in alveolar bone fixation devices.展开更多
As a physical interface,a prosthetic liner is commonly used as a transition material between the residual limb and the stiff socket.Typically made from a compliant material such as silicone,the main function of a pros...As a physical interface,a prosthetic liner is commonly used as a transition material between the residual limb and the stiff socket.Typically made from a compliant material such as silicone,the main function of a prosthetic liner is to protect the residual limb from injuries induced by load-bearing normal and shear stresses.Compared to conventional liners,custom prosthetic lower-extremity(LE)liners have been shown to better relieve stress concentrations in painful and sensitive regions of the residual limb.Although custom LE liners have been shown to offer clinical benefits,no review article on their design and efficacy has yet been written.To address this shortcoming in the literature,this paper provides a comprehensive survey of custom LE liner materials,design,and fabrication methods.First,custom LE liner materials and components are summarized,including a description of commercial liners and their efficacy.Subsequently,digital methods used to design and fabricate custom LE liners are addressed,including residual limb biomechanical modeling,finite element-based design methods,and 3-D printing techniques.Finally,current evaluation methods of custom/commercial LE liners are presented and discussed.We hope that this review article will inspire further research and development into the design and manufacture of custom LE liners.展开更多
The development of small-diameter vascular grafts that can meet the long-term patency required for implementation in clinical practice presents a key challenge to the research field.Although techniques such as the bra...The development of small-diameter vascular grafts that can meet the long-term patency required for implementation in clinical practice presents a key challenge to the research field.Although techniques such as the braiding of scaffolds can offer a tunable platform for fabricating vascular grafts,the effects of braided silk fiber skeletons on the porosity,remodeling,and patency in vivo have not been thoroughly investigated.展开更多
Bone marrow mesenchymal stem cells(BMSCs),periosteal stem cells(PSCs),and other bone stem cells originate from embryonic bone formation,but their function and stem cell characteristics such as proliferation ability an...Bone marrow mesenchymal stem cells(BMSCs),periosteal stem cells(PSCs),and other bone stem cells originate from embryonic bone formation,but their function and stem cell characteristics such as proliferation ability and differentiation ability change at different anatomical locations.Perichondral-derived stem cells(PCSCs)are more closely related to PSCs in origin and function,usually used to be studied together with PSCs as one type of stem cell.However,this leads to the ignoration of the PCSCs'characteristics.Since the anatomical locations of these two types of stem cells diverse,PCSCs should have some differences from PSCs.In this study,the PCSCs in the perichondrium surrounding the growth plate cartilage expressed CTSK and CD200 same as PSCs.However,when compared the stem cell characteristics of PCSCs with that of PSCs,PCSCs were more elongated than PSCs in morphology and have stronger self-renewal ability,as well as stronger chondrogenic and adipogenic differentiation potentials.This study revealed the stem cell characteristics of PCSCs distinguished from PSCs,which may indicate PCSCs and PSCs should not be treated as one type of cell to research in the future.展开更多
Iliac vein compression syndrome(IVCS)is a common venous disease caused by joint compression of the right common iliac artery and the lumbosacral vertebrae.The compression of iliac vein not only causes venous hypertens...Iliac vein compression syndrome(IVCS)is a common venous disease caused by joint compression of the right common iliac artery and the lumbosacral vertebrae.The compression of iliac vein not only causes venous hypertension in the lower extremities,but also induces venous valve dysfunction and superficial varicose veins in lower extremities.Moreover,the compression of iliac vein is an important potential factor for iliofemoral vein thrombosis.Currently,open surgery and stent implantation are the main treatment for IVCS.Due to the advantages of minimally invasive and postoperative patency,stent implantation for IVCS has gradually become the standard treatment.However,when the stent is implanted into the iliac vein to treat IVCS,the complications,such as restenosis,deep vein thrombosis(DVT)appear,which affect the patency of stent and hamper the patient recovery.Up to now,the mechanism how the stent implantation induces the restenosis and DVT is still unclear.In this review,we summarized the clinical symptoms,treatment methods of IVCS and the complications after stent implantation,and analyzed the mechanism of stent restenosis and DVT,and finally discuss the iliac vein stent design specifically for treating IVCS.展开更多
Due to the limited capacity of corneal endothelial cells(CECs)division,corneal endothelial diseases have become a great challenge.The cornea is subjected to various mechanical stimuli in vivo,which may have a positive...Due to the limited capacity of corneal endothelial cells(CECs)division,corneal endothelial diseases have become a great challenge.The cornea is subjected to various mechanical stimuli in vivo,which may have a positive or negative influence.Thus,it is significant to gain an insight into the mechanism of mechanobiology of CECs for seeking more possible treatment.The purpose of this study was to determine the impacts of mechanical stretch and substrate stiffness on the morphology and fundamental cell behavior of CECs.Rabbit corneal endothelial cells(RCECs)were subjected to a 5%mechanical stretch or cultured on substrates of different stiffness.The impacts of mechanical stimulus on cell area,aspect ratio,circularity,cell density,nuclear shape,cytoskeleton,and cell viability were investigated.The expressions of the corneal endothelium-related markers ZO-1 and Na^(+)/K^(+) ATPase were also evaluated by confocal immunofluorescence microscopy in the stiffness group.Our results suggested that mechanical stretch promoted the rearrangement of the cytoskeleton while decreasing the cell circularity,nuclear area,and cell density as well as cell viability.RCECs cultured on 10 kPa substrates,which was close to the physiological stiffness of rabbit Descemet's membrane(DM),showed better cell morphology,more stable actin cytoskeleton assembly,and more robust expression of the functional marker compared with other softer or stiffer substrates.In summary,mechanical stretch and substrate stiffness have profound influences on the morphology and function of CECs,which may have implications for the understanding and possible treatment of corneal endothelial diseases.展开更多
This paper presents a novel tendon-driven soft prosthetic hand with 5 fingers and 9 independent actuators.A special notched structure was used as the finger joint,which brings adequate compliance to grasping.The soft ...This paper presents a novel tendon-driven soft prosthetic hand with 5 fingers and 9 independent actuators.A special notched structure was used as the finger joint,which brings adequate compliance to grasping.The soft finger has two kinds of vertically arranged joints that can produce flexion/extension and abduction/adduction motions under tension and release,enabling a three-dimensional workspace of the finger and improving the dexterity of the hand.The design and manufacture of the finger and soft hand are described in detail.An openloop kinematic model based on piecewise constant curvature of the finger was established and verified experimentally.The results show that the model could precisely predict finger movement.The slip resistance of the soft hand was tested,and the capacity to grasp objects was evaluated based on power grasp and precision grasp.With abduction joints,the proposed hand can perform various gestures and in-hand manipulations,which indicate high dexterity.This work provides a way to realize high dexterity for soft prosthetic hands.展开更多
基金supported by the National Natural Science Foundation of China(Nos.11872097,11827803 and U20A20390)the National Key R&D Program of China(No.2020YFC0122204)the 111 Project(No.B13003).
文摘The bone matrix plays an indispensable role in the human body,and its unique biomechanical and mechanobiological properties have received much attention.The bone matrix has unique mechanical anisotropy and exhibits both strong toughness and high strength.These mechanical properties are closely associated with human life activities and correspond to the function of bone in the human body.None of the mechanical properties exhibited by the bone matrix is independent of its composition and structure.Studies on the biomechanics of the bone matrix can provide a reference for the preparation of more applicable bone substitute implants,bone biomimetic materials and scaffolds for bone tissue repair in humans,as well as for biomimetic applications in other fields.In providing mechanical support to the human body,bone is constantly exposed to mechanical stimuli.Through the study of the mechanobiology of the bone matrix,the response mechanism of the bone matrix to its surrounding mechanical environment can be elucidated and used for the health maintenance of bone tissue and defect regeneration.This paper summarizes the biomechanical properties of the bone matrix and their biological significance,discusses the compositional and structural basis by which the bone matrix is capable of exhibiting these mechanical properties,and studies the effects of mechanical stimuli,especially fluid shear stress,on the components of the bone matrix,cells and their interactions.The problems that occur with regard to the biomechanics and mechanobiology of the bone matrix and the corresponding challenges that may need to be faced in the future are also described.
基金financial support from the Beijing Natural Science Foundation(No.L234020)the National Natural Science Foundation of China(Nos.12472325 and 12272032)the 111 Project(No.B13003).
文摘Microneedles(MNs)are an innovative and viable option for drug delivery that offer the distinct advantages of minimal invasiveness,painlessness,stable drug loading,efficient drug permeation,and biocompatibility.MNs were first used to penetrate the skin surface and facilitate transcutaneous drug delivery with great success.Recent applications of MNs have extended to non-transdermal drug delivery,specifically,to various tissues and organs.This review captures the fabrication methods for MNs,discusses advanced design strategies for achieving controlled drug release,and summarizes current MN applications in delivering multiple therapeutic agents to the cardiovascular,digestive(e.g.,oral cavity),reproductive,and central nervous systems.The findings in this review would contribute toward the improved designs of MN systems that can be modified according to purpose,including material selection,structural design,choice of fabrication methods,and tissue considerations,to determine the optimal therapeutic regimen for the target treatment area.
基金supported by National Natural Science Foundation of China(No.81970987).
文摘Accurate segmentation of oral surgery-related tissues from cone beam computed tomography(CBCT)images can significantly accelerate treatment planning and improve surgical accuracy.In this paper,we propose a fully automated tissue segmentation system for dental implant surgery.Specifically,we propose an image preprocessing method based on data distribution histograms,which can adaptively process CBCT images with different parameters.Based on this,we use the bone segmentation network to obtain the segmentation results of alveolar bone,teeth,and maxillary sinus.We use the tooth and mandibular regions as the ROI regions of tooth segmentation and mandibular nerve tube segmentation to achieve the corresponding tasks.The tooth segmentation results can obtain the order information of the dentition.The corresponding experimental results show that our method can achieve higher segmentation accuracy and efficiency compared to existing methods.Its average Dice scores on the tooth,alveolar bone,maxillary sinus,and mandibular canal segmentation tasks were 96.5%,95.4%,93.6%,and 94.8%,respectively.These results demonstrate that it can accelerate the development of digital dentistry.
基金supported by the National Nature Science Foundation of China(Grant Nos.11972066,U20A20390,and 11827803)the support of Open Fund of State Key Laboratory of Virtual Reality Technology and Systems。
文摘This study aimed to conduct finite element(FE)analysis matched with an in vitro experiment to analyze traumatic retinal detachments(TrRD)resulting from blunt trauma and provide stress and strain thresholds to predict the occurrence of TrRD.The in vitro experiment was performed on forty-eight porcine eyes using a pendulum device.We examined dynamic mechanical responses at four energy levels.A FE model,based on experimental results and published data,was used to simulate TrRD.Fifty-one additional eyes underwent immediate pathological examination following blunt impact.A dynamic variation of velocities was observed post-impact,displaying an approximate cosine oscillation-attenuation profile.Energy absorption increased as the initial energy and differed significantly at four energy levels(p<0.001).FE simulation showed a peak strain of 0.462 in the anterior vitreous body and a peak stress of 1.408 MPa at the cornea at the high-energy level.During the energy transfer,the stress was initially observed in retinal region along the impact direction at the separation.TrRD were observed in injured eyes,where a few detachments were detected in control eyes.Correlations were performed between the proportion of pathological outcomes and FE results.In conclusion,this study suggests that stress contributes to the development of retinal detachment,providing an indicator to distinguish the occurrence of TrRD.
基金supported by NSFC(62273019,52072015,12332019,U20A20390)the 111 Project(B13003)。
文摘Dear Editor,This letter presents a biocompatible cross-shaped magnetic soft robot and investigates its deformation mode control strategy through COMSOL modeling and simulation.Magnetic soft robots offer novel avenues for precise treatment within intricate regions of the human body.
基金financially supported by the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology(YESS,No.2020QNRC001)the National Science and Technology Resources Investigation Program of China(No.2021FY100603)the Fundamental Research Funds for the Central Universities(No.FRF-BD-20-28A2)。
文摘Metal corrosion causes significant economic losses,safety issues,and environmental pollution.Hence,its prevention is of immense research interest.Carbon dots(CDs)are a new class of zero-dimensional carbon nanomaterials,which have been considered for corrosion protection applications in recent years due to their corrosion inhibition effect,fluorescence,low toxicity,facile chemical modification,and cost-effectiveness.This study provides a comprehensive overview of the synthesis,physical and chemical properties,and anticorrosion mechanisms of functionalized CDs.First,the corrosion inhibition performance of different types of CDs is introduced,followed by discussion on their application in the development of smart protective coatings with self-healing and/or self-reporting properties.The effective barrier formed by CDs in the coatings can inhibit the spread of local damage and achieve self-healing behavior.In addition,diverse functional groups on CDs can interact with Fe^(3+)and H^(+)ions generated during the corrosion process;this interaction changes their fluorescence,thereby demonstrating self-reporting behavior.Moreover,challenges and prospects for the development of CD-based corrosion protection systems are also presented.
基金supported by the National Natural Science Foundation of China(Nos.91959120 and 62027824)Basic Research Program for Beijing-Tianjin-Hebei Coordination(19JCZDJC65500(Z))+1 种基金Open Project Program of Wuhan National Laboratory for Optoelectronics(No.2018WNLOKF026)Fundamental Research Funds for the Central Universities(YWF-22-L-547).
文摘Cancer cells dysregulate lipid metabolism to accelerate energy production and biomolecule synthesis for rapid growth.Lipid metabolism is highly dynamic and intrinsically heterogeneous at the single cell level.Although°uorescence microscopy has been commonly used for cancer research,bulky°uorescent probes can hardly label small lipid molecules without perturbing their biological activities.Such a challenge can be overcome by coherent Raman scattering(CRS)microscopy,which is capable of chemically selective,highly sensitive,submicron resolution and high-speed imaging of lipid molecules in single live cells without any labeling.Recently developed hyperspectral and multiplex CRS microscopy enables quantitative mapping of various lipid metabolites in situ.Further incorporation of CRS microscopy with Raman tags greatly increases molecular selectivity based on the distinct Raman peaks well separated from the endogenous cellular background.Owing to these unique advantages,CRS microscopy sheds new insights into the role of lipid metabolism in cancer development and progression.This review focuses on the latest applications of CRS microscopy in the study of lipid metabolism in cancer.
基金supported financially by the Fundamental Research Funds for the Central Universities (YWF-22-K-101,YWF-23-L-805 and YWF-23-YG-QB-006)the support from the National Natural Science Foundation of China (12372106)Fundamental Research Funds for the Central Universities
文摘3D printing techniques offer an effective method in fabricating complex radially multi-material structures.However,it is challenging for complex and delicate radially multi-material model geometries without supporting structures,such as tissue vessels and tubular graft,among others.In this work,we tackle these challenges by developing a polar digital light processing technique which uses a rod as the printing platform.The 3D model fabrication is accomplished through line projection.The rotation and translation of the rod are synchronized to project and illuminate the photosensitive material volume.By controlling the distance between the rod and the printing window,we achieved the printing of tubular structures with a minimum wall thickness as thin as 50 micrometers.By controlling the width of fine slits at the printing window,we achieved the printing of structures with a minimum feature size of 10 micrometers.Our process accomplished the fabrication of thin-walled tubular graft structure with a thickness of only 100 micrometers and lengths of several centimeters within a timeframe of just 100 s.Additionally,it enables the printing of axial multi-material structures,thereby achieving adjustable mechanical strength.This method is conducive to rapid customization of tubular grafts and the manufacturing of tubular components in fields such as dentistry,aerospace,and more.
基金National Natural Science Foundation of China(82001920,82071301,81820108012)Beijing Municipal Administration of Hospitals’Youth Programme(QML20210503).
文摘Background Identification of futile recanalisation following endovascular therapy(EVT)in patients with acute ischaemic stroke is both crucial and challenging.Here,we present a novel risk stratification system based on hybrid machine learning method for predicting futile recanalisation.Methods Hybrid machine learning models were developed to address six clinical scenarios within the EVT and perioperative management workflow.These models were trained on a prospective database using hybrid feature selection technique to predict futile recanalisation following EVT.The optimal model was validated and compared with existing models and scoring systems in a multicentre prospective cohort to develop a hybrid machine learning-based risk stratification system for futile recanalisation prediction.Results Using a hybrid feature selection approach,we trained and tested multiple classifiers on two independent patient cohorts(n=1122)to develop a hybrid machine learning-based prediction model.The model demonstrated superior discriminative ability compared with other models and scoring systems(area under the curve=0.80,95%CI 0.73 to 0.87)and was transformed into a web application(RESCUE-FR Index)that provides a risk stratification system for individual prediction(accessible online atfr-index.biomind.cn/RESCUE-FR/).Conclusions The proposed hybrid machine learning approach could be used as an individualised risk prediction model to facilitate adherence to clinical practice guidelines and shared decision-making for optimal candidate selection and prognosis assessment in patients undergoing EVT.
基金supported by the National Natural Science Foundation of China(T2288101,12172034,U20A20390,11827803)Beijing Municipal Natural Science Foundation(7212205)the 111 project(B13003)and the Fundamental Research Funds for the Central Universities。
文摘Poly(glycerol-dodecanoate)(PGD)has aroused increasing attention in biomedical engineering for its degradability,shape memory and rubber-like mechanical properties,giving it potential to fabricate intelligent implants for soft tissues.Adjustable degradation is important for biodegradable implants and is affected by various factors.The mechanical load has been shown to play an important role in regulating polymer degradation in vivo.An in-depth investigation of PGD degradation under mechanical load is essential for adjusting its degradation behavior after implantation,further guiding to regulate degradation behavior of soft tissue implants made by PGD.In vitro degradation of PGD under different compressive and tensile load has proceeded in this study and describes the relationships by empirical equations.Based on the equations,a continuum damage model is designed to simulate surface erosion degradation of PGD under stress through finite element analysis,which provides a protocol for PGD implants with different geometric structures at varied mechanical conditions and provides solutions for predicting in vivo degradation processes,stress distribution during degradation and optimization of the loaded drug release.
基金This work was supported by Key research and development plan of the Ministry of science and technology of China[2019YFC0118002]National Natural Science Foundation(NSFC)Grant of China[61871019]+1 种基金Beijing science and technology project[Z18110001918024]Natural Science Foundation of Beijing[19L2011].
文摘Pelvic fracture is among the most complicated fractures in traumatic orthopedics,with high mortality and morbidity rates.The main difficulty associated with the reduction surgery is significant muscle resistance.It then becomes necessary to decrease the reduction force against this strong muscle resistance,for improving surgical safety.Here,we propose a novel traction method for decreasing the reduction force during pelvic reduction,and investigate the performance of the elastic traction method on decreasing the reduction force using experimental tests and simulation-based analyses.From the experimental results,the reduction force decreased by 59.2%when 10 kg of elastic traction was applied.We also establish a musculoskeletal model of the pelvic fracture reduction,for analyzing the muscle resistance and the optimal traction force applied in reduction surgeries.The elastic traction method can counteract the muscle resistance increase in the non-traction direction owing to its flexibility.We conclude that the optimal traction force applied should be in the 10–15 kg range,and recommend adopting a dynamic traction strategy rather than continuous traction in clinical settings.Elastic traction is very promising for various surgeries that require traction,including pelvic reduction.It significantly reduces force,which can significantly reduce the physical exertion of the operating surgeon,the possibility of additional injuries to the operated patient,and promotes robot-assisted reduction surgeries.
基金financially supported by the National Natural Science Foundation of China(Nos.12272032,11872097,11827803 and U20A20390)the National Key R&D Program of China(No.2020YFC0122204)the 111 Project(No.B13003).
文摘As the quality of life improves,people pay more and more attention to health.They are concerned about the causes of diseases,and seek better treatments.The most common diseases are biomineralized diseases,four different kinds of typical examples among which are selected to elaborate their mechanisms and existing treatments.Whether it is tooth and bone in physiological mineralization or cartilage and blood vessel in pathological mineralization,they are all related to matrix vesicle(MV)-mediated biomineralization.MV-mediated biomineralization is the initial stage of biomineralization and the nucleation site mediating collagen mineralization.Definition,composition,biogenesis,and action mechanism of MVs are refined and expounded,especially a novel biomineralization pathway similar to exosome(EX)origin.Four differences are summarized to distinguish MVs and EXs.A series of treatments using MVs to solve biomineralized diseases such as tooth and bone defects,osteoarthritis and atherosclerosis are proposed,and the experimental extraction steps of MVs are summarized.
基金This work was financially supported by the National Natural Science Foundation of China(No.12272032)the National Key R&D Program of China(No.2020YFC0122204)the 111 Project(No.B13003).
文摘Androgenetic alopecia(AGA)is an androgen-mediated alopecia affected by both genes and hormones.Medication is a relatively common treatment.As a new drug delivery method,microneedles(MNs)can effectively break through the stratum corneum barrier,deliver drugs more efficiently,and achieve better therapeutic effects.In this study,we develop a composite double-layer MN through multi-step casting fabrication using a polydimethylsiloxane mold.The needle tip was fabricated by mixed solution of chitosan and polyvinylpyrrolidone which was loaded with Polygonum multiflorum extract,and the base layer was prepared by mixed solution of polyvinyl alcohol and polyvinylpyrrolidone.In vitro mechanical tests showed that the maximum load of a single tip of the drug-loaded MN was about 3.5 N,which met the mechanical requirements of skin puncture(>1 N).The drug release experiment showed that the MN could achieve gradual drug release.In the animal experiment,pigmentation and hair regrowth occurred earlier in the Polygonum multiflorum-MN(Pm-MN)group than in the other groups,and hair growth finally appeared in almost the entire area.Compared with the AGA model mice,mice in the Pm-MN group achieved an increase in the number and diameter of hair follicles.In conclusion,the Pm-MN is scientific and feasible for treating AGA.
基金supported by the National Key R&D,Program of China (No.2018YFC1106600)the National Natural Science Foundation of China (Nos.52071008 and U20A20390)Beijing Natural Science Foundation (No.2192027).
文摘Alveolar bone augmentation with fixation screws has difficulties such as non-degradable materials that could lead to secondary surgery and insufficient osseointegration due to the subgingival environment in dental practice.With degradability and a high degree of osteogenesis,Mg alloy is a successful biodegrad-able material for orthopedic applications,and its application in dentistry has made certain progress.How-ever,considering the unique subgingival healing properties of oral implants,there is still a gap between the desired material properties for clinical applications and available materials.Indeed,studies on the use of Mg-based fixation screws for dentistry applications are still rare.In this study,we reported a magnesium alloy with low combined addition of strontium and lanthanum.The mechanical properties,degradation behavior,osteogenesis,and gingival compatibility were systematically investigated for assess-ing its potential application in alveolar bone fixation screws.With the alloying element content restricted to 0.3 wt.%,Mg-Sr-La alloy still exhibited good mechanical properties,with yield tensile and compressive strength twice higher than those of pure Mg.The in vitro degradation rate of this alloy was 0.10 mm y-1,which was slightly slower than high-purity Mg.The indirect and direct cell assay confirmed the elevated osteoblastic differentiation of MC3T3-E1 and migration of HGF-1 cells.Moreover,Mg-Sr-La alloy demon-strated a relatively slow degradation in the maxillary bone of Beagles.A remarkable promotion of the bone-implant contacts and significantly decreased fibrous encapsulation was observed in the subgingival environment,implying superior osseointegration of the experimental alloy than the titanium control.The empirical findings here reveal the great potential of Mg-Sr-La alloy for the application in alveolar bone fixation devices.
基金supported by the Fundamental Research Funds for the Central Universities(Grant number JKF-YG-22-B010)the National Institutes of Health(Grant number 5R01EB024531-03).
文摘As a physical interface,a prosthetic liner is commonly used as a transition material between the residual limb and the stiff socket.Typically made from a compliant material such as silicone,the main function of a prosthetic liner is to protect the residual limb from injuries induced by load-bearing normal and shear stresses.Compared to conventional liners,custom prosthetic lower-extremity(LE)liners have been shown to better relieve stress concentrations in painful and sensitive regions of the residual limb.Although custom LE liners have been shown to offer clinical benefits,no review article on their design and efficacy has yet been written.To address this shortcoming in the literature,this paper provides a comprehensive survey of custom LE liner materials,design,and fabrication methods.First,custom LE liner materials and components are summarized,including a description of commercial liners and their efficacy.Subsequently,digital methods used to design and fabricate custom LE liners are addressed,including residual limb biomechanical modeling,finite element-based design methods,and 3-D printing techniques.Finally,current evaluation methods of custom/commercial LE liners are presented and discussed.We hope that this review article will inspire further research and development into the design and manufacture of custom LE liners.
基金The authors graciously acknowledge professor Deling Kong's lab for their assistance with the animal experiments.This project was supported by the National Natural Science Foundation of China(T2288101,32000968,32071359,11827803,and U20A20390)Beijing Natural Science Foundation(M22026)Fundamental Research Funds for the Central Universities,and 111 Project(B13003).
文摘The development of small-diameter vascular grafts that can meet the long-term patency required for implementation in clinical practice presents a key challenge to the research field.Although techniques such as the braiding of scaffolds can offer a tunable platform for fabricating vascular grafts,the effects of braided silk fiber skeletons on the porosity,remodeling,and patency in vivo have not been thoroughly investigated.
基金This research was funded by the National Natural Science Foundation of China,grants number 11972068 and 12002026funded by the China Space Station Engineering Experiment Project,grants number HYZHXM01016.
文摘Bone marrow mesenchymal stem cells(BMSCs),periosteal stem cells(PSCs),and other bone stem cells originate from embryonic bone formation,but their function and stem cell characteristics such as proliferation ability and differentiation ability change at different anatomical locations.Perichondral-derived stem cells(PCSCs)are more closely related to PSCs in origin and function,usually used to be studied together with PSCs as one type of stem cell.However,this leads to the ignoration of the PCSCs'characteristics.Since the anatomical locations of these two types of stem cells diverse,PCSCs should have some differences from PSCs.In this study,the PCSCs in the perichondrium surrounding the growth plate cartilage expressed CTSK and CD200 same as PSCs.However,when compared the stem cell characteristics of PCSCs with that of PSCs,PCSCs were more elongated than PSCs in morphology and have stronger self-renewal ability,as well as stronger chondrogenic and adipogenic differentiation potentials.This study revealed the stem cell characteristics of PCSCs distinguished from PSCs,which may indicate PCSCs and PSCs should not be treated as one type of cell to research in the future.
基金This work was supported by the National Key R&D Program of China(Grant no.2020YFC0862900,2020YFC0862902,2020YFC0862904 and 2020YFC0122203)the Beijing Municipal Science and Technology Project(Grant no.Z201100007920003)+1 种基金the National Natural Science Foundation of China(Grant no.32071311)Key R&D project of Shanxi Province(Grant no.201903D321149).
文摘Iliac vein compression syndrome(IVCS)is a common venous disease caused by joint compression of the right common iliac artery and the lumbosacral vertebrae.The compression of iliac vein not only causes venous hypertension in the lower extremities,but also induces venous valve dysfunction and superficial varicose veins in lower extremities.Moreover,the compression of iliac vein is an important potential factor for iliofemoral vein thrombosis.Currently,open surgery and stent implantation are the main treatment for IVCS.Due to the advantages of minimally invasive and postoperative patency,stent implantation for IVCS has gradually become the standard treatment.However,when the stent is implanted into the iliac vein to treat IVCS,the complications,such as restenosis,deep vein thrombosis(DVT)appear,which affect the patency of stent and hamper the patient recovery.Up to now,the mechanism how the stent implantation induces the restenosis and DVT is still unclear.In this review,we summarized the clinical symptoms,treatment methods of IVCS and the complications after stent implantation,and analyzed the mechanism of stent restenosis and DVT,and finally discuss the iliac vein stent design specifically for treating IVCS.
基金National Natural Science Foundation of China(NSFC)Research Grants(U20A20390,11827803,11402017).
文摘Due to the limited capacity of corneal endothelial cells(CECs)division,corneal endothelial diseases have become a great challenge.The cornea is subjected to various mechanical stimuli in vivo,which may have a positive or negative influence.Thus,it is significant to gain an insight into the mechanism of mechanobiology of CECs for seeking more possible treatment.The purpose of this study was to determine the impacts of mechanical stretch and substrate stiffness on the morphology and fundamental cell behavior of CECs.Rabbit corneal endothelial cells(RCECs)were subjected to a 5%mechanical stretch or cultured on substrates of different stiffness.The impacts of mechanical stimulus on cell area,aspect ratio,circularity,cell density,nuclear shape,cytoskeleton,and cell viability were investigated.The expressions of the corneal endothelium-related markers ZO-1 and Na^(+)/K^(+) ATPase were also evaluated by confocal immunofluorescence microscopy in the stiffness group.Our results suggested that mechanical stretch promoted the rearrangement of the cytoskeleton while decreasing the cell circularity,nuclear area,and cell density as well as cell viability.RCECs cultured on 10 kPa substrates,which was close to the physiological stiffness of rabbit Descemet's membrane(DM),showed better cell morphology,more stable actin cytoskeleton assembly,and more robust expression of the functional marker compared with other softer or stiffer substrates.In summary,mechanical stretch and substrate stiffness have profound influences on the morphology and function of CECs,which may have implications for the understanding and possible treatment of corneal endothelial diseases.
基金The research was supported by“National Key R&D Program of China”under Grant 2017YFA0701101.
文摘This paper presents a novel tendon-driven soft prosthetic hand with 5 fingers and 9 independent actuators.A special notched structure was used as the finger joint,which brings adequate compliance to grasping.The soft finger has two kinds of vertically arranged joints that can produce flexion/extension and abduction/adduction motions under tension and release,enabling a three-dimensional workspace of the finger and improving the dexterity of the hand.The design and manufacture of the finger and soft hand are described in detail.An openloop kinematic model based on piecewise constant curvature of the finger was established and verified experimentally.The results show that the model could precisely predict finger movement.The slip resistance of the soft hand was tested,and the capacity to grasp objects was evaluated based on power grasp and precision grasp.With abduction joints,the proposed hand can perform various gestures and in-hand manipulations,which indicate high dexterity.This work provides a way to realize high dexterity for soft prosthetic hands.
