Engineering hydrogels that resemble biological tissues of various lengths via conventional fabrication techniques remains challenging.Three-dimensional(3D)bioprinting has emerged as an advanced approach for constructi...Engineering hydrogels that resemble biological tissues of various lengths via conventional fabrication techniques remains challenging.Three-dimensional(3D)bioprinting has emerged as an advanced approach for constructing complex biomimetic 3D architectures,which are currently restricted by the limited number of available bioinks with high printability,biomimicry,biocompatibility,and proper mechanical properties.Inspired by ubiquitous coacervation phenomena in biology,we present a unique mineral-biopolymer coacervation strategy that enables the hierarchical assembly of nanoclay and recombinant human collagen(RHC).This system was observed to undergo a coacervation transition(liquid‒liquid phase separation)spontaneously.The formed dense phase separated from its supernatant is the coacervate of clay-RHC-rich complexes,where polymer chains are sandwiched between silicate layers.Molecular dynamics simulation was first used to verify and explore the coacervation process.Then,the coacervates were demonstrated to be potential bioinks that exhibited excellent self-supporting and shear-thinning viscoelastic properties.Through extrusion-based printing,the versatility of the bioink was demonstrated by reconstructing the key features of several biological tissues,including multilayered lattice,vascular,nose,and ear-like structures,without the need for precrosslinking operations or support baths.Furthermore,the printed scaffolds were cytocompatible,elicited minimal inflammatory responses,and promoted bone regeneration in calvarial defects.展开更多
Copper,permalloy,cobalt,and silicon are the materials that have been widely utilised in magnetic devices.When the size of interest is down to the nanoscale,the inter-diffusion between certain materials becomes influen...Copper,permalloy,cobalt,and silicon are the materials that have been widely utilised in magnetic devices.When the size of interest is down to the nanoscale,the inter-diffusion between certain materials becomes influential.This paper studies the nanoscale friction characteristics between frictional pairs with and without inter-diffusion properties through the atomic force microscope.The distinct evolution features of nanoscale friction force when inter-diffusion is involved are discovered experimentally,which is also confirmed through theoretical analysis.Firstly,through the thin film deposition method,four pairs of contact materials(Cu–Ni_(81)Fe_(19),Si–Ni_(81)Fe_(19),Cu–Co,Cu–Si)are designed for friction tests,in which diffusion occurs at the interface of Cu–Ni_(81)Fe_(19)pair.Then,the effects of sliding velocity and loading force on the nano friction of each pair are measured.It is found that regardless of the diffusion phenomenon:(1)the adhesion force values exhibit a notable correlation to the values of the friction force;(2)the friction force in all four material pairs consistently increases with the growth of the normal loading force,although the growth rate may differ.In terms of the sliding velocity effect,the friction forces of immiscible materials(Si–Ni_(81)Fe_(19),Cu–Co,and Cu–Si)are found to increase with the increasing sliding velocity.However,the friction force of Cu–Ni_(81)Fe_(19),decreases with the increasing sliding velocity.Furthermore,a compositive friction model considering both the velocity and the normal force effect was proposed,which shows good agreement with the experimental results and explains the nano friction behaviour of both miscible and immiscible metals.展开更多
Virus identification is a prerequisite not only for the early diagnosis of viral infectious diseases but also for the effective prevention of epidemics.Successful cultivation is the gold standard for identifying a vir...Virus identification is a prerequisite not only for the early diagnosis of viral infectious diseases but also for the effective prevention of epidemics.Successful cultivation is the gold standard for identifying a virus,according to the Koch postulates.However,this requires screening for a permissive cell line,which is traditionally time-,reagent-and labor-intensive.Here,a simple and easy-to-operate microfluidic chip,formed by seeding a variety of cell lines and culturing them in parallel,is reported for use in virus cultivation and virus-permissive host-cell screening.The chip was tested by infection with two known viruses,enterovirus 71(EV71)and influenza virus H1N1.Infection with EV71 and H1N1 caused significant cytopathic effects(CPE)in RD and MDCK cells,respectively,demonstrating that virus cultivation based on this microfluidic cell chip can be used as a substitute for the traditional plate-based culture method and reproduce the typical CPE caused by virus infection.Using this microfluidic cell chip method for virus cultivation could make it possible to identify an emerging virus in a highthroughput,automatic,and unprecedentedly fast way.展开更多
基金the projects of National Natural Science Foundation of China(No.32301209)Key R&D Projects of Henan Province(Nos.231111312400 and 241111220400).
文摘Engineering hydrogels that resemble biological tissues of various lengths via conventional fabrication techniques remains challenging.Three-dimensional(3D)bioprinting has emerged as an advanced approach for constructing complex biomimetic 3D architectures,which are currently restricted by the limited number of available bioinks with high printability,biomimicry,biocompatibility,and proper mechanical properties.Inspired by ubiquitous coacervation phenomena in biology,we present a unique mineral-biopolymer coacervation strategy that enables the hierarchical assembly of nanoclay and recombinant human collagen(RHC).This system was observed to undergo a coacervation transition(liquid‒liquid phase separation)spontaneously.The formed dense phase separated from its supernatant is the coacervate of clay-RHC-rich complexes,where polymer chains are sandwiched between silicate layers.Molecular dynamics simulation was first used to verify and explore the coacervation process.Then,the coacervates were demonstrated to be potential bioinks that exhibited excellent self-supporting and shear-thinning viscoelastic properties.Through extrusion-based printing,the versatility of the bioink was demonstrated by reconstructing the key features of several biological tissues,including multilayered lattice,vascular,nose,and ear-like structures,without the need for precrosslinking operations or support baths.Furthermore,the printed scaffolds were cytocompatible,elicited minimal inflammatory responses,and promoted bone regeneration in calvarial defects.
基金the National Natural Science Foundation of China(No.52171193)China Postdoctoral Science Foundation(No.2019M652564)Henan Postdoctoral Science Foundation(No.19030013)。
文摘Copper,permalloy,cobalt,and silicon are the materials that have been widely utilised in magnetic devices.When the size of interest is down to the nanoscale,the inter-diffusion between certain materials becomes influential.This paper studies the nanoscale friction characteristics between frictional pairs with and without inter-diffusion properties through the atomic force microscope.The distinct evolution features of nanoscale friction force when inter-diffusion is involved are discovered experimentally,which is also confirmed through theoretical analysis.Firstly,through the thin film deposition method,four pairs of contact materials(Cu–Ni_(81)Fe_(19),Si–Ni_(81)Fe_(19),Cu–Co,Cu–Si)are designed for friction tests,in which diffusion occurs at the interface of Cu–Ni_(81)Fe_(19)pair.Then,the effects of sliding velocity and loading force on the nano friction of each pair are measured.It is found that regardless of the diffusion phenomenon:(1)the adhesion force values exhibit a notable correlation to the values of the friction force;(2)the friction force in all four material pairs consistently increases with the growth of the normal loading force,although the growth rate may differ.In terms of the sliding velocity effect,the friction forces of immiscible materials(Si–Ni_(81)Fe_(19),Cu–Co,and Cu–Si)are found to increase with the increasing sliding velocity.However,the friction force of Cu–Ni_(81)Fe_(19),decreases with the increasing sliding velocity.Furthermore,a compositive friction model considering both the velocity and the normal force effect was proposed,which shows good agreement with the experimental results and explains the nano friction behaviour of both miscible and immiscible metals.
基金the Scientific Instrument Developing Project of the Chinese Academy of Sciences(No.YJKYYQ20190057)the National Nature Science Foundation of China(No.81827804)+1 种基金the CAS Emergency Project of ASF Research(No.KJZDSW-L06-02)Applied Basic Research Program of Wuhan(No.2018060401011327)。
文摘Virus identification is a prerequisite not only for the early diagnosis of viral infectious diseases but also for the effective prevention of epidemics.Successful cultivation is the gold standard for identifying a virus,according to the Koch postulates.However,this requires screening for a permissive cell line,which is traditionally time-,reagent-and labor-intensive.Here,a simple and easy-to-operate microfluidic chip,formed by seeding a variety of cell lines and culturing them in parallel,is reported for use in virus cultivation and virus-permissive host-cell screening.The chip was tested by infection with two known viruses,enterovirus 71(EV71)and influenza virus H1N1.Infection with EV71 and H1N1 caused significant cytopathic effects(CPE)in RD and MDCK cells,respectively,demonstrating that virus cultivation based on this microfluidic cell chip can be used as a substitute for the traditional plate-based culture method and reproduce the typical CPE caused by virus infection.Using this microfluidic cell chip method for virus cultivation could make it possible to identify an emerging virus in a highthroughput,automatic,and unprecedentedly fast way.
