title: Hybrid scaffold bearing polymer-siloxane Schiff base linkage for bone tissue engineering.
abstract: Scaffolds that can provide the requisite biological cues for the fast regeneration of bone are highly relevant to the advances in tissue engineering and regenerative medicine. In the present article, we report the fabrication of a chitosan-gelatin-siloxane scaffold bearing interpolymer-siloxane Schiff base linkage, through a single-step dialdehyde cross-linking and freeze-drying method using 3-aminopropyltriethoxysilane as the siloxane precursor. Swelling of the scaffolds in phosphate buffered saline indicates enhancement with increase in siloxane concentration, whereas compressive moduli of the wet scaffolds reveal inverse dependence, owing to the presence of siloxane, rich in silanol groups. It is suggested that through the strategy of dialdehyde cross-linking, a limiting siloxane loading of 20 wt.% into a chitosan -gelatin matrix should be considered ideal for bone tissue engineering, because the scaffold made with 30 wt.% siloxane loading degrades by 48 wt.%, in 21 days. The hybrid scaffolds bearing Schiff base linkage between the polymer and siloxane, unlike the stable linkages in earlier reports, are expected to give a faster release of siloxanes and enhancement in osteogenesis. This is verified by the in vitro evaluation of the hybrid scaffolds using rabbit adipose mesenchymal stem cells, which revealed osteogenic cell-clusters on a polymer-siloxane scaffold, enhanced alkaline phosphatase activity and the expression of bone-specific genes, whereas the control scaffold without siloxane supported more of cell-proliferation than differentiation. A siloxane concentration dependent enhancement in osteogenic differentiation is also observed.
authors.affiliation: Division of Tissue Engineering and Regeneration Technologies, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695012, Kerala, India. Electronic address: bindumelekkuttu@gmail.com.
authors.forename: Bindu P
authors.initials: BP
authors.lastname: Nair
authors.affiliation: Division of Tissue Engineering and Regeneration Technologies, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695012, Kerala, India.
authors.forename: Dhanya
authors.initials: D
authors.lastname: Gangadharan
authors.affiliation: Division of Tissue Engineering and Regeneration Technologies, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695012, Kerala, India.
authors.forename: Neethu
authors.initials: N
authors.lastname: Mohan
authors.affiliation: Division of Tissue Engineering and Regeneration Technologies, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695012, Kerala, India.
authors.forename: Babitha
authors.initials: B
authors.lastname: Sumathi
authors.affiliation: Division of Tissue Engineering and Regeneration Technologies, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695012, Kerala, India. Electronic address: pdnair49@gmail.com.
authors.forename: Prabha D
authors.initials: PD
authors.lastname: Nair
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000737:chemistry*; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D010012:Osteogenesis / Q000502:physiology; D011108:Polymers / Q000737:chemistry*; D011817:Rabbits; D012545:Schiff Bases / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry*; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry
chemical_list: D011108:Polymers; D012545:Schiff Bases; D012833:Siloxanes
keywords: Biomineralisation; Bone tissue engineering; Cell-clustering; Osteogenesis; Siloxane