ABSTRACT
A honeycomb composite is useful to carry cells for application in bone, cartilage, skin, and soft tissue regenerative therapies. To fabricate a composite, and expand the application of mollusca shells as well as improve preparing methods of calcium alginate in tissue engineering research, Anodonta woodiana shell powder was mixed with sodium alginate at varying mass ratios to obtain a gel mixture. The mixture was frozen and treated with dilute hydrochloric acid to generate a shell matrix/calcium alginate composite. Calcium carbonate served as the control. The composite was transplanted subcutaneously into rats. At 7, 14, 42, and 70 days after transplantation, frozen sections were stained with hematoxylin and eosin, followed by DAPI, ß-actin, and collagen type-I immunofluorescence staining, and observed using laser confocal microscopy. The composite featured a honeycomb structure. The control and composite samples displayed significantly different mechanical properties. The water absorption rate of the composite and control group were respectively 205-496% and 417-586%. The composite (mass ratio of 5:5) showed good biological safety over a 70-day period; the subcutaneous structure of the samples was maintained and the degradation rate was lower than that of the control samples. Freezing the gel mixture afforded control over chemical reaction rates. Given these results, the composite is a promising honeycomb scaffold for tissue engineering.
Subject(s)
Alginates/pharmacology , Animal Shells/chemistry , Hydrogels/pharmacology , Tissue Scaffolds , Actins/genetics , Actins/metabolism , Alginates/chemistry , Animals , Biomarkers/metabolism , Collagen Type I/genetics , Collagen Type I/metabolism , Elastic Modulus , Female , Gene Expression , Glucuronic Acid/chemistry , Glucuronic Acid/pharmacology , Hexuronic Acids/chemistry , Hexuronic Acids/pharmacology , Hydrochloric Acid/chemistry , Hydrogels/chemical synthesis , Injections, Subcutaneous , Male , Mollusca/chemistry , Powders/chemistry , Powders/pharmacology , Rats , Rats, Sprague-Dawley , Tensile Strength , Tissue EngineeringABSTRACT
To investigate the structure of silk and its degradation properties, we have monitored the structure of silk using scanning electron microscopy and frozen sections. Raw silk and degummed raw silk were immersed in four types of degradation solutions for 156 d to observe their degradation properties. The subcutaneous implants in rats were removed after 7, 14, 56, 84, 129, and 145 d for frozen sectioning and subsequent staining with hematoxylin and eosin (H.E.), DAPI, Beta-actin and Collagen I immunofluorescence staining. The in vitro weight loss ratio of raw silk and degummed raw silk in water, PBS, DMEM and DMEM containing 10% FBS (F-DMEM) were, respectively, 14%/11%, 12.5%/12.9%, 11.1%/14.3%, 8.8%/11.6%. Silk began to degrade after 7 d subcutaneous implantation and after 145 d non-degraded silk was still observed. These findings suggest the immunogenicity of fibroin and sericin had no essential difference. In the process of in vitro degradation of silk, the role of the enzyme is not significant. The in vivo degradation of silk is related to phagocytotic activity and fibroblasts may be involved in this process to secrete collagen. This study also shows the developing process of cocoons and raw silk.
