Collagen-Chitosan (COL-CS) scaffolds supplemented with different concentrations (0.1-0.5%) of aloe vera (AV) were prepared and tested in vitro for their possible application in tissue engineering. After studying the microstructure and mechanical properties of all the composite preparations, a 0.2% AV blended COL-CS scaffold was chosen for further studies. Scaffolds were examined by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and thermogravimetry analysis (TGA) to understand the intermolecular interactions and their influence on the thermal property of the complex composite. Swelling property in phosphate buffered saline (pH 7.4) and in vitro biodegradability by collagenase digestion method were monitored to assess the stability of the scaffold in a physiological medium in a hydrated condition, and to assay its resistance against enzymatic forces. The scanning electron microscope (SEM) image of the scaffold samples showed porous architecture with gradual change in their morphology and reduced tensile properties with increasing aloe vera concentration. The FTIR spectrum revealed the overlap of the AV absorption peak with the absorption peak of COL-CS. The inclusion of AV to COL-CS increased the thermal stability as well as hydrophilicity of the scaffolds. Cell culture studies on the scaffold showed enhanced growth and proliferation of fibroblasts (3T3L1) without exhibiting any toxicity. Also, normal cell morphology and proliferation were observed by fluorescence microscopy and SEM. The rate of cell growth in the presence/absence of aloe vera in the scaffolds was in the order: COL-CS-AV > COL-CS > TCP (tissue culture polystyrene plate). These results suggested that the aloe vera gel-blended COL-CS scaffolds could be a promising candidate for tissue engineering applications.

Artificial tissue constructs require vehicles for controlled release of growth factor to induce cellular signaling in vivo conditions. The objective of this study was to develop a three-dimensional porous tissue engineering scaffold with the capability of carrying nanoparticles for their controlled release. Epidermal growth factor and fibroblast growth factor were encapsulated into chitosan nanoparticles of an average diameter of 50–100 nm. Porous collagen–chitosan scaffolds were prepared by freeze-drying method. The pores of the scaffolds were well interconnected, with a mean diameter of 75–150 µm. The in vitro release kinetics data indicated that nanoparticle impregnated scaffolds released epidermal growth factor and fibroblast growth factor in a sustainable manner. The cytocompatibility, proliferation, and cell attachment characteristics of the biopolymeric scaffolds were evaluated through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, flow cytometry, and scanning electron microscope. The results demonstrated that the dual delivery of epidermal growth factor and fibroblast growth factor from chitosan nanoparticles of collagen–chitosan scaffolds significantly enhanced the cellular viability and activity. The in vitro data clearly confirmed that the growth factors incorporated in chitosan nanoparticles and placed in hybrid scaffolds have favorable characteristics for drug delivery and tissue engineering application.

The purpose of this study was to evaluate the in vitro macrophage compatibility, the inflammatory response and in vivo host response to a novel collagen-chitosan (COL-CS) scaffold containing growth factors incorporated Chitosan Nanoparticle (CNP). The scaffold was obtained by freezing a blend of COL-CS solution and growth factor incorporated CNP followed by lyophilization. High Resolution Transmission Electron Micrograph (HR-TEM) indicated that growth factors incorporated CNP were in the size range of 50-100 nm, while Scanning Electron Microscopic (SEM) analysis of the scaffold surface suggests that the pores of the scaffolds (COL-CS) were well interconnected, with a mean diameter of 75-150 microm. Macrophages grown on growth factors containing scaffold exhibited poor inflammatory response compared to scaffold without growth factors. In vivo biocompatibility and host response study of scaffold was performed by subcutaneous implantation and examination of the implanted material on day 3 and 15 post implant. The dual growth factors viz. EGF (Epidermal Growth Factor) and FGF (Fibroblast Growth Factor) incorporated implant showed a distinct fibrous capsule boundary on the surface. Secondly, the immunofluoresence assay and zymography respectively for TNFalpha and MMP9 exhibited low expression of these inflammatory markers. These observations divulge that the growth factors when incorporated, can suppress the inflammatory properties of the scaffolds and thus such scaffolds could be used in tissue engineering for minimal host response and enhanced tissue-scaffold interaction.

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