Porous Collagen Scaffold Reinforced with Surfaced Activated PLLA Nanoparticles

Porous collagen scaffold is integrated with surface activated PLLA nanoparticles fabricated by lyophilizing and crosslinking via EDC treatment. In order to prepare surface-modified PLLA nanoparticles, PLLA was firstly grafted with poly (acrylic acid) (PAA) through surface-initiated polymerization of acrylic acid. Nanoparticles of average diameter 316 nm and zeta potential −39.88 mV were obtained from the such-treated PLLA by dialysis method. Porous collagen scaffold were fabricated by mixing PLLA nanoparticles with collagen solution, freeze drying, and crosslinking with EDC. SEM observation revealed that nanoparticles were homogeneously dispersed in collagen matrix, forming interconnected porous structure with pore size ranging from 150 to 200 μm, irrespective of the amount of nanoparticles. The porosity of the scaffolds kept almost unchanged with the increment of the nanoparticles, whereas the mechanical property was obviously improved, and the degradation was effectively retarded. In vitro L929 mouse fibroblast cells seeding and culture studies revealed that cells infiltrated into the scaffolds and were distributed homogeneously. Compared with the pure collagen sponge, the number of cells in hybrid scaffolds greatly increased with the increment of incorporated nanoparticles. These results manifested that the surface-activated PLLA nanoparticles effectively reinforced the porous collagen scaffold and promoted the cells penetrating into the scaffold, and proliferation

CerealsDB 3.0:Expansion of resources and data integration

BACKGROUND: The increase in human populations around the world has put pressure on resources, and as a consequence food security has become an important challenge for the 21st century. Wheat (Triticum aestivum) is one of the most important crops in human and livestock diets, and the development of wheat varieties that produce higher yields, combined with increased resistance to pests and resilience to changes in climate, has meant that wheat breeding has become an important focus of scientific research. In an attempt to facilitate these improvements in wheat, plant breeders have employed molecular tools to help them identify genes for important agronomic traits that can be bred into new varieties. Modern molecular techniques have ensured that the rapid and inexpensive characterisation of SNP markers and their validation with modern genotyping methods has produced a valuable resource that can be used in marker assisted selection. CerealsDB was created as a means of quickly disseminating this information to breeders and researchers around the globe. DESCRIPTION: CerealsDB version 3.0 is an online resource that contains a wide range of genomic datasets for wheat that will assist plant breeders and scientists to select the most appropriate markers for use in marker assisted selection. CerealsDB includes a database which currently contains in excess of a million putative varietal SNPs, of which several hundreds of thousands have been experimentally validated. In addition, CerealsDB also contains new data on functional SNPs predicted to have a major effect on protein function and we have constructed a web service to encourage data integration and high-throughput programmatic access. CONCLUSION: CerealsDB is an open access website that hosts information on SNPs that are considered useful for both plant breeders and research scientists. The recent inclusion of web services designed to federate genomic data resources allows the information on CerealsDB to be more fully integrated with the WheatIS network and other biological databases. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12859-016-1139-x) contains supplementary material, which is available to authorized users

A model for facilitating translational research and development in China: Call for establishing a Hong Kong Branch of the Chinese National Engineering Research Centre for Biomaterials

With significant improvements in living standards in China and the aging population that accompanies these improvements, the market demand for high-quality orthopaedic biomaterials for clinical applications is tremendous and growing rapidly. There are major efforts to promote cooperation between different scientific institutes with complementary strengths for the further development of the biomaterial industry in China to achieve the technological level of developed countries. An excellent example is that the Ministry of Science and Technology of the People's Republic of China (MOST; Beijing, China) established the Chinese National Engineering Research Centres (CNERCs), which serve as a major initiative in driving basic and applied technological research and development (R&D) in mainland China. To create a win-win situation with Hong Kong, the MOST and the Hong Kong Innovation and Technology Commission are jointly establishing the Hong Kong Branch of the CNERCs. Through an amicable arrangement, the Chinese University of Hong Kong (CUHK; Shatin, Hong Kong) and the Chinese National Engineering Research Centre for Biomaterials (i.e., Main Centre) in Chengdu, People's Republic of China have decided to apply to establish the Hong Kong Branch of the CNERC for Biomaterials at the CUHK. The effort in establishing the Hong Kong Branch of Biomaterials seeks to promote further collaboration with the Main Centre with the goals of promoting synergy and a win-win cooperation between mainland China and Hong Kong in scientific research, talent cultivation, clinically driven novel biomaterials product design, and preclinical and clinical testing. It will thus become a model for the successful collaboration between the Hong Kong research institutions and the mainland CNERCs in the area of biomaterials. Such initiatives will facilitate close collaboration in translational medicine associated with biomaterial development and application

Rab32 facilitates Schwann cell pyroptosis in rats following peripheral nerve injury by elevating ROS levels

Abstract Background Peripheral nerve injury (PNI) is commonly observed in clinical practice, yet the underlying mechanisms remain unclear. This study investigated the correlation between the expression of a Ras-related protein Rab32 and pyroptosis in rats following PNI, and potential mechanisms have been explored by which Rab32 may influence Schwann cells pyroptosis and ultimately peripheral nerve regeneration (PNR) through the regulation of Reactive oxygen species (ROS) levels. Methods The authors investigated the induction of Schwann cell pyroptosis and the elevated expression of Rab32 in a rat model of PNI. In vitro experiments revealed an upregulation of Rab32 during Schwann cell pyroptosis. Furthermore, the effect of Rab32 on the level of ROS in mitochondria in pyroptosis model has also been studied. Finally, the effects of knocking down the Rab32 gene on PNR were assessed, morphology, sensory and motor functions of sciatic nerves, electrophysiology and immunohistochemical analysis were conducted to assess the therapeutic efficacy. Results Silencing Rab32 attenuated PNI-induced Schwann cell pyroptosis and promoted peripheral nerve regeneration. Furthermore, our findings demonstrated that Rab32 induces significant oxidative stress by damaging the mitochondria of Schwann cells in the pyroptosis model in vitro. Conclusion Rab32 exacerbated Schwann cell pyroptosis in PNI model, leading to delayed peripheral nerve regeneration. Rab32 can be a potential target for future therapeutic strategy in the treatment of peripheral nerve injuries

Bioinspired supramolecular nanofiber hydrogel through self-assembly of biphenyl-tripeptide for tissue engineering

Supramolecular nanofiber peptide assemblies had been used to construct functional hydrogel biomaterials and achieved great progress. Here, a new class of biphenyl-tripeptides with different C-terminal amino acids sequences transposition were developed, which could self-assemble to form robust supramolecular nanofiber hydrogels from 0.7 to 13.8 kPa at ultra-low weight percent (about 0.27 wt%). Using molecular dynamics simulations to interrogate the physicochemical properties of designed biphenyl-tripeptide sequences in atomic detail, reasonable hydrogen bond interactions and “FF” brick (phenylalanine-phenylalanine) promoted the formation of supramolecular fibrous hydrogels. The biomechanical properties and intermolecular interactions were also analyzed by rheology and spectroscopy analysis to optimize amino acid sequence. Enhanced L929 cells adhesion and proliferation demonstrated good biocompatibility of the hydrogels. The storage modulus of BPAA-AFF with 10 nm nanofibers self-assembling was around 13.8 kPa, and the morphology was similar to natural extracellular matrix. These supramolecular nanofiber hydrogels could effectively support chondrocytes spreading and proliferation, and specifically enhance chondrogenic related genes expression and chondrogenic matrix secretion. Such biomimetic supramolecular short peptide biomaterials hold great potential in regenerative medicine as promising innovative matrices because of their simple and regular molecular structure and excellent biological performance

Molecular co-assembled strategy tuning protein conformation for cartilage regeneration

Abstract The assembly of oligopeptide and polypeptide molecules can reconstruct various ordered advanced structures through intermolecular interactions to achieve protein-like biofunction. Here, we develop a “molecular velcro”-inspired peptide and gelatin co-assembly strategy, in which amphiphilic supramolecular tripeptides are attached to the molecular chain of gelatin methacryloyl via intra-/intermolecular interactions. We perform molecular docking and dynamics simulations to demonstrate the feasibility of this strategy and reveal the advanced structural transition of the co-assembled hydrogel, which brings more ordered β-sheet content and 10-fold or more compressive strength improvement. We conduct transcriptome analysis to reveal the role of co-assembled hydrogel in promoting cell proliferation and chondrogenic differentiation. Subcutaneous implantation evaluation confirms considerably reduced inflammatory responses and immunogenicity in comparison with type I collagen. We demonstrate that bone mesenchymal stem cells-laden co-assembled hydrogel can be stably fixed in rabbit knee joint defects by photocuring, which significantly facilitates hyaline cartilage regeneration after three months. This co-assembly strategy provides an approach for developing cartilage regenerative biomaterials

Nanofibrous polypeptide hydrogels with collagen-like structure as biomimetic extracellular matrix

Abstract Supramolecular peptides exhibit obvious similarities with collagen fibers in terms of self-assembly characteristics, nanofibrous structure, and responsiveness to external stimuli. Here, a series of supramolecular peptides were developed by altering the amino acid sequence, enabling the self-assembly of three types of 4-biphenylacetic acid (BPAA)-tripeptides into fibrous hydrogel through hydrogen bonding and π–π stacking under the influence of ion induction. Transmission electron and scanning electron microscopies revealed that the diameter of the fiber within nanofibrous hydrogels was ~ 10 and ~ 40 nm, respectively, which was similar with the self-assembled collagen fibers. For this reason, these hydrogels could be considered as a biomimetic extracellular substitute. Meanwhile, the gelation concentration induced by ions was even lower than 0.66 wt%, with an elastic modulus of ~ 0.27 kPa, corresponding to a water content of 99.34 wt%. In addition, the three supramolecular hydrogels were found to be good substrates for L929 cell adhesion and MC-3T3 cell proliferation. The overall results implied that BPAA-based hydrogels have a lucrative application potential as cell carriers. Graphical Abstrac