Bioactive 3D-printed chitosan-based scaffolds for personalized craniofacial bone tissue engineering

Regeneration of craniofacial bone defects is a key issue in the bone regeneration field.Hence,novel treatment strategies,such as tissue engineering using porous scaffolds,have been developed.An ideal tissue-engineered scaffold for bone tissue regeneration should possess pores to facilitate nutrients transmission and support repar-ative tissue ingrowth,bioactivity for osteoconduction and osseointegration,and biocompatibility to improve cell attachment,proliferation,and extracellular matrix formation.In the present study,we manufactured chitosan-based hydrogels substituted with alginate with optimized properties by extrusion-based three-dimensional(3D)printing.3D printing of the scaffolds enables the designing and developing of complex architectures for cranio-facial reconstruction using computer-aided design(CAD).Different ratios(2.5,5,and 10%)of hydroxyapatite were added to the hydrogel,printed,and subsequently lyophilized to augment the physical and biological char-acteristics of the scaffolds.Hydroxyapatite incorporation into the chitosan-based scaffolds increased the porosity and pore size of the printed scaffolds.In addition,the presence of hydroxyapatite amplified apatite formation and decreased the size of formed apatite crystals.All the scaffold samples showed biocompatible properties and did not have toxicity toward rat bone marrow mesenchymal stem cells.Furthermore,the scaffolds containing 5%w/w hydroxyapatite exhibited significant growth in cell viability compared to the control.Overall,it is concluded that chitosan-based scaffolds adorned with hydroxyapatite are considerable for regenerating craniofacial bone defects.

Protein biomarkers of neural system

The utilization of biomarkers for in vivo and in vitro research is growing rapidly. This is mainly due to the enormous potential of biomarkers in evaluating molecular and cellular abnormalities in cell models and in tissue, and evaluating drug responses and the effectiveness of therapeutic intervention strategies. An important way to analyze the development of the human body is to assess molecular markers in embryonic specialized cells, which include the ectoderm, mesoderm, and endoderm. Neuronal development is controlled through the gene networks in the neural crest and neural tube, both components of the ectoderm. The neural crest differentiates into several different tissues including, but not limited to, the peripheral nervous system, enteric nervous system, melanocyte, and the dental pulp. The neural tube eventually converts to the central nervous system. This review provides an overview of the differentiation of the ectoderm to a fully functioning nervous system, focusing on molecular biomarkers that emerge at each stage of the cellular specialization from multipotent stem cells to completely differentiated cells. Particularly, the otic placode is the origin of most of the inner ear cell types such as neurons, sensory hair cells, and supporting cells. During the development, different auditory cell types can be distinguished by the expression of the neurogenin differentiation factor1 (Neuro D1), Brn3a, and transcription factor GATA3. However, the mature auditory neurons express other markers including bIII tubulin, the vesicular glutamate transporter (VGLUT1), the tyrosine receptor kinase B and C (Trk B, C), BDNF, neurotrophin 3 (NT3), Calretinin, etc.

Lawsone-encapsulated chitosan/polyethylene oxide nanofibrous mat as a potential antibacterial biobased wound dressing

Biodegradable and absorptive wound dresses with antibacterial activity are in demand to accelerate wound heal-ing along with eliminating bacterial infection.Plant-derived naphthoquinones compounds such as lawsone have shown sustained antibacterial functions to avoid development of bacterial resistance by reducing pH or attaching to bacterial proteins.Here the nanofibrous mats based on chitosan/polyethylene oxide(PEO)fibers containing various concentrations of lawsone(0,1,3,7,10%wt.)were fabricated by electrospinning for potential applications as wound dressing materials.The results exhibited that the chitosan/PEO/Lawsone nanofibers possess antibacterial activity toward Gram-negative and-positive bacteria.Surprisingly,the addition of lawsone in the proper amount into chitosan/PEO nanofibers not only introduced an antithetical property but also reduced the platform’s cytotoxicity,promoting cell viability of normal human fibroblast cells.Accordingly,the achieved data suggest the potential application of biocompatible nanofibrous mats as an antibacterial wound dressing material.