摘要：Specific and dynamic biological interactions pave the blueprint of signal networks in cell. For example, a great variety of specific protein-ligand interactions define how intracellular signals flow. Taking advantage of the specificity of these interactions, we postulate an "affinity-guided covalent conjugation" strategy to lock binding ligands through covalent reactions between the ligand and the receptor protein. The presence of a nucleophile close to the ligand binding site of a protein is sine qua none of this reaction. Specific noncovalent interaction of a ligand derivative(which contains an electrophile at a designed position) to the ligand binding site of the protein brings the electrophile to the close proximity of the nucleophile. Subsequently, a conjugation reaction spontaneously takes place between the nucleophile and the electrophile, and leads to an intermolecular covalent linkage. This strategy was first showcased in coiled coil peptides which include a cysteine mutation at a selected position. The short peptide sequence was used for covalent labeling of cell surface receptors. The same strategy was then used to guide the design of a set of protein Lego bricks for covalent assembly of protein complexes of unnatural geometry. We finally made "reactive peptides" for natural adaptor proteins that play significant roles in signal transduction. The peptides were designed to react with a single domain of the multidomain adaptor protein, delivered into the cytosol of neurons, and re-directed the intracellular signal of neuronal migration. The trilogy of protein labeling, assembly, and inhibition of intracellular signals, all through a specific covalent bond, fully demonstrated the generality and versatility of "affinity-guided covalent conjugation" in various applications.

摘要：Polyhydroxyalkanoates （PHAs）, as a candidate for biodegradable plastic materials, can be synthesized by numerous microorganisms. However, as its production cost is high in comparison with those of chemically synthesized plastics, a lot of research has been focused on the efficient production of PHAs using different methods. In the present study, the mutation effects of PHAs production in strain pCB4 were investigated with implantation of low energy ions. It was found that under the implantation conditions of 7.8×10^14 N^＋/cm^2 at 10 keV, a high-yield PHAs strain with high genetic stability was generated from many mutants. After optimizing its fermentation conditions, the biomass, PHAs concentration and PHAs content of pCBH4 reached 2.26 g/L, 1.81 g/L, and 80.08% respectively, whereas its wild type controls were about 1.24 g/L, 0.61 g/L, and 49.20%. Moreover, the main constituent of PHAs was identified as poly-3-hydroxybutyrates （PHB） in the mutant stain and the yield of this compound was increased up to 41.33% in contrast to that of 27.78% in the wild type strain.

摘要：Wounds heal through a complex process including four *** interruption or interference in healing process can prevent wound *** is one of the most common complications preventing wounds from *** this study,we investigated the fibroblast cell morphology and behavior of a gelatin-based hydrogel containing anthocyanin to determine whether it can be used for early detection of *** experimental results ascertained that 6 h after culturing the fibroblasts,they could be well attached to the surface of the hydrogel,and 48 h after seeding,they were spread over the surface and connected with each *** the addition of a low dose of anthocyanin,the vitality of the cell increased,and the results of the ATR-FTIR analysis showed that anthocyanin could eliminate remaining glutaraldehyde free *** also could change its color after the addition of bacterial ***,hydrogels containing black carrot anthocyanin may be a potential therapeutic and diagnostic strategy to promote wound healing and early detection of infection.

摘要：Introduction The climax of the industrial revolution was marked by the rapid growth of industry,and advancement in technologies have further fueled this industrial expansion,leading to a surge in economic *** technologies have also increased the degree of destructive human inter-ference with the biosphere.

摘要：In this study,boron-doped hydroxyapatite(BHT)-loaded alginate/gelatin-based(A/G)hydrogel coating on Ti was fabricated to support bone integration through triggering osteoinduction,vascularization and ***,highly reproducible,cheap and time-effective BHT was produced,which significantly promoted higher osteogenic and angiogenic maturation,while a mild innate immune response was *** immense potential of BHT was evidenced by the production of a gap-filling A/G/BHT interphase on Ti implants to mimic the osseous extracellular matrix to achieve functional bridging and exert control over the course of innate immune *** initially aminosilanized the implant surface using 3-aminopropyl triethoxysilane,and then coated it with 0.25%w/v alginate with 20 mM 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide to allowthe A/G/BHT pre-gel to disperse evenly and covalently attach on the *** pre-gel was added with 0.2 M NaCl to homogeneously blend BHT in the structure without inducing ionic ***,the coated implants were freeze-dried and *** coated layer demonstrated high cohesive and adhesive strength,and 8-month-long shelf-life at room temperature and normal *** A/G/BHT was able to coat an irregularly shaped Ti *** and endothelial cells thrived on the A/G/BHT,and it demonstrated greatly improved osteogenic and angiogenic ***,A/G/BHT maintained macrophage viability and generated an acute increase in immune response that could be resolved ***,A/G/BHT was shown to induce the robust integration of implant in a rabbit femur osteochondral model within ***,we concluded that A/G/BHT coatings could serve as amultifunctional reservoir,promoting the strong and rapid osseointegration of metallic implants.

摘要：Polymer-mediated self-assembly of superparamagnetic iron oxide（SPIO） nanoparticles allows modulation of the structure of SPIO nanocrystal cluster and their magnetic properties. In this study, dopamine-functionalized polyesters（DApolyester） were used to directly control the magnetic nanoparticle spacing and its effect on magnetic resonance relaxation properties of these clusters was investigated. Monodisperse SPIO nanocrystals with different surface coating materials（poly（ε-caprolactone）, poly（lactic acid）） of different molecular weights containing dopamine（DA） structure（DA-PCL2k,DA-PCL1k, DA-PLA1k）） were prepared via ligand exchange reaction, and these nanocrystals were encapsulated inside amphiphilic polymer micelles to modulate the SPIO nanocrystal interparticle spacing. Small-angle x-ray scattering（SAXS）was applied to quantify the interparticle spacing of SPIO clusters. The results demonstrated that the tailored magnetic nanoparticle clusters featured controllable interparticle spacing providing directly by the different surface coating of SPIO nanocrystals. Systematic modulation of SPIO nanocrystal interparticle spacing can regulate the saturation magnetization（Ms） and T2 relaxation of the aggregation, and lead to increased magnetic resonance（MR） relaxation properties with decreased interparticle spacing.

摘要：This novel face mask is designed to be a reusable respirator with a small and highly efficient disposable fabric *** material requirements are reduced by 75%compared to traditional designs and allow repeated cleaning or *** probability of virus particle inhalation is reduced using novel air filtration pathways,through square-waveform design to increase filter *** enters the mask from right and left side filters,while the area in front of the mouth is *** epoxy is used for a transparent frame,allowing lip-reading,and mask edges contain a silicone seal preventing bypass of the *** mask is manufactured using silicone molds,eliminating electricity requirements making it economical and viable in developing *** fluid dynamics numerical studies and Fluent ANSYS software were used to simulate airflow through the filter to optimize filter air path geometry and validate mask design with realistic human *** breathing cycle was represented as a transient function,and N95 filter specifications were selected as a porous *** novel design achieved 1.2×10^(−3) kg s^(−1),20%higher than human requirements,with air streamlines velocity indicating local high speed,forcing and trapping virus particles against filter walls through centrifugal forces.

摘要：The optimization of the scaffolds to provide a suitable matrix and accelerate the regeneration process is vital for bone tissue ***,poor mechanical and biological characteristics remain the primary challenges that must be *** example,although bredigite(Br)has shown great potential for application in bone tissue engineering,it easily fails in *** the present work,these challenges are addressed by reinforcing the Br matrix with nanosheets of graphene oxide(rGO)that have been reduced by bovine serum albumin(BSA)in order to enhance the mechanical properties and biological *** reduction of graphene oxide by BSA improves the water stability of the nanosheets and provides an electrostatic interaction between theBSA-rGO nanosheets and theBr *** high thermal conductivity of theBSA-rGO nanosheets decreases the porosity of the Br by transferring heat to the core of the ***,the addition of BSA-rGO nanosheets into the Br matrix enhances the adhesion of G-292 cells on the surface of the *** findings suggest that the tablet consisting of BSA-rGO-reinforced Br has encouraging potential for application in bone tissue engineering.

摘要：Tissue-engineered bone scaffolds provide temporary mechanical support for bone tissue growth. Mechanical stimuli are transferred to seeded cells through the scaffold structure to promote cell proliferation and differentiation. This paper presents a numerical investigation specifically on bone and cartilage tissue differentiation with the aim to provide a theoretical basis for scaffold design and bone defect repair in clinics. In this study, the scaffold structures were established on the basis of cancellous bone microarchitectures. For finite element simulations, inlet velocity and compressive strain were applied under in vitro culture conditions. The influences of this scaffold mor- phology and macro-level culture conditions on micro-mechanical stimuli at scaffold surfaces were investigated. Correlations between the microarchitectural parameters and the mechanical parameters, as well as the cell differentiation parameters were analyzed. Highly het- erogeneous stress distributions were observed on the scaffolds with irregular morphology. Cell differentiation on the scaffold was more sensitive to the inlet velocity than the axial strain. In addition, cartilage differentiation on the scaffolds with structures comprising more plate-like trabeculae was more pronounced than on those with more rod-like trabeculae. This paper is helpful to gain more insight into the mechanical environments under in vitro culture conditions that approximate the in vivo mechanical environments of Bone Marrow Stromal Ceils （BMSCs）.

摘要：The bone regenerative scaffold with the tailored degradation rate matching with the growth rate of the new bone is essential for adolescent bone *** satisfy these requirement,we proposed bone tissue scaffolds with controlled degradation rate using osteoinductive materials(Ca-P bioceramics),which is expected to present a controllable biodegradation rate for patients who need bone *** properties,porosity,compressive strength and degradation properties of the scaffolds were studied.3D printed Ca-P scaffold(3DS),gas foaming Ca-P scaffold(FS)and autogenous bone(AB)were used in vivo for personalized beagle skull defect *** results indicated that the 3DS was highly vascularized and well combined with surrounding *** showed obvious newly formed bone *** showed the best repair effect,but it was found that AB scaffolds were partially absorbed and *** study indicated that the 3D printed Ca-P bioceramics with tailored biodegradation rate is a promising candidate for personalized skull bone tissue reconstruction.