Topology optimization of microstructure and selective laser meltingfabrication for metallic biomaterial scaffolds

The precise design and fabrication of biomaterial scaffolds is necessary to provide a systematic study for bone tissue engineering. Biomaterial scaffolds should have sufficient stiffness and large porosity. These two goals generally contradict since larger porosity results in lower mechanical properties. To seek the microstructure of maximum stiffness with the constraint of volume fraction by topology optimization method, algorithms and programs were built to obtain 2D and 3D optimized microstructure and then they were transferred to CAD models of STL format. Ti scaffolds with 30% volume fraction were fabricated using a selective laser melting （SLM） technology. The architecture and pore shape in the metallic biomaterial scaffolds were relatively precise reproduced and the minimum mean pore size was 231μm. The accurate fabrication of intricate microstructure has verified that the SLM process is suitable for fabrication of metallic biomaterial scaffolds.

Biomaterial scaffolds in maxillofacial bone tissue engineering:A review of recent advances

Maxillofacial bone defects caused by congenital malformations,trauma,tumors,and inflammation can severely affect functions and aesthetics of maxillofacial region.Despite certain successful clinical applications of biomaterial scaffolds,ideal bone regeneration remains a challenge in maxillofacial region due to its irregular shape,complex structure,and unique biological functions.Scaffolds that address multiple needs of maxillofacial bone regeneration are under development to optimize bone regeneration capacity,costs,operational convenience.etc.In this review,we first highlight the special considerations of bone regeneration in maxillofacial region and provide an overview of the biomaterial scaffolds for maxillofacial bone regeneration under clinical examination and their efficacy,which provide basis and directions for future scaffold design.Latest advances of these scaffolds are then discussed,as well as future perspectives and challenges.Deepening our understanding of these scaffolds will help foster better innovations to improve the outcome of maxillofacial bone tissue engineering.

Advances of adipose-derived mesenchymal stem cells-based biomaterial scaffolds for oral and maxillofacial tissue engineering

The management of oral and maxillofacial tissue defects caused by tumors,trauma,and congenital or acquired deformities has been a major challenge for surgeons over the last few decades.Autologous tissue transplantation,the gold standard of tissue reconstruction,is a valid method for repairing the oral and maxillofacial functions and aesthetics.However,several limitations hinder its clinical applications including complications of donor sites,limited tissue volume,and uncertain long-term outcomes.Adipose-derived mesenchymal stem cells(ADMSCs)widely exist in adipose tissue and can be easily obtained through liposuction.Like the bone marrow-derived mesenchymal stem cells(BMSCs),ADMSCs also have the multi-pluripotent potencies to differentiate into osteoblasts,chondrocytes,neurons,and myocytes.Therefore,the multilineage capacity of ADMSCs makes them valuable for cell-based medical therapies.In recent years,researchers have developed many candidates of ADMSCs-based biomaterial scaffolds to cater for the needs of oral and maxillofacial tissue engineering due to their superior performance.This review presents the advances and applications of ADMSCs-based biomaterial scaffolds,and explores their tissue engineering prospects in oral and maxillofacial reconstructions.

Extracellular matrix from human umbilical cordderived mesenchymal stem cells as a scaffold for peripheral nerve regeneration

The extracellular matrix,which includes collagens,laminin,or fibronectin,plays an important role in peripheral nerve regeneration.Recently,a Schwann cell-derived extracellular matrix with classical biomaterial was used to mimic the neural niche.However,extensive clinical use of Schwann cells remains limited because of the limited origin,loss of an autologous nerve,and extended in vitro culture times.In the present study,human umbilical cord-derived mesenchymal stem cells（h UCMSCs）,which are easily accessible and more proliferative than Schwann cells,were used to prepare an extracellular matrix.We identified the morphology and function of h UCMSCs and investigated their effect on peripheral nerve regeneration.Compared with a non-coated dish tissue culture,the h UCMSC-derived extracellular matrix enhanced Schwann cell proliferation,upregulated gene and protein expression levels of brain-derived neurotrophic factor,glial cell-derived neurotrophic factor,and vascular endothelial growth factor in Schwann cells,and enhanced neurite outgrowth from dorsal root ganglion neurons.These findings suggest that the h UCMSC-derived extracellular matrix promotes peripheral nerve repair and can be used as a basis for the rational design of engineered neural niches.

Preparation and Properties of Collagen-Chitosan/Glycosaminoglycans as Candidate Tissue Engineering Biomaterials

A novel biomaterial scaffold was created from collagen chitosan/GAG. Its tensile strength was 8.6MPa(wet state)and degree of swelling water was 60%～75% with higer ultimate elongation 300%. Rabbit corneas of collagen chitosan/GAG implantation samples in vivo for biodegradation showed that the inplantion samples was complets biodegrable and digested afere 120 day. There was enought time to maintain cell growth,immigrating and proliferation. This biomaterials scaffold can be used for cell culture and in various tissue engineering fields.

A Brief Summary of Current Therapeutic Strategies for Spinal Cord Injury

Spinal cord injury(SCI)is a tremendous disaster in a person’s life.It interrupts the brain-body neuronal circuits,resulting in functional deficits.Pathogenesis of SCI is a progressive and comprehensive event.In clinical trials,attempts to promote nerve regeneration and functional recovery after SCI have met with failures.Recently,with the development of transcriptome sequencing and biomaterials,researchers have struggled to explore novel efficient therapeutic treatments for SCI.Here,we summarize the recent pro-gress that has been made in SCI repair based on the lesion microenvironment,neural circuits,and bioma-terial scaffolds.We also propose several important directions for future research,including targeted-microRNA therapy,blood vessel interventions,and multiple treatment combinations.In short,we hope this review will enlighten researchers in the field and pave the way for SCI therapy.