Designing tailored biomaterial surfaces to direct keratinocyte morphology, attachment, and differentiation

Abstract

Precisely engineering the surface chemistry of biomaterials to modulate the adsorption and functionality of biochemical signaling molecules that direct cellular functions is critical in the development of tissue engineered scaffolds. Specifically, this study describes the use of functionalized self-assembled monolayers (SAMs) as a model system to assess the effects of biomaterial surface properties on controlling fibronectin (FN) conformation and concentration as well as keratinocyte function. By systematically analyzing FN adsorption at low and saturated surface densities, we distinguished between SAM dependent effects of FN concentration and conformation on presenting cellular binding domains that direct cellular functions. Quantitative image analyses of immunostained samples showed that modulating the availability of the FN synergy site directly correlated with changes in keratinocyte attachment, spreading, and differentiation, through integrin mediated signaling mechanisms. The results of this study will be used to elucidate design features that can be incorporated into dermal equivalents and percutaneous implants to enhance the rate of reepithelialization and tissue regeneration. Furthermore, these findings indicate that SAM based model systems are a valuable tool for designing and investigating the development of scaffolds that regulate the conformation of extracellular matrix cues and cellular functions that accelerate the rate of tissue regeneration.

The Influence of Tetracycline Loading on the Surface Morphology and Biocompatibility of Films Made from P(3HB) Microspheres

“…However, due to some disadvantages such as prolonged healing times and limited tissue functionality, alternative biodegradable polymers have been considered. [1][2][3] For skin graft or wound healing studies one of the most commonly used cell types is the human adult low calcium high temperature (HaCaT) cell line. These cell lines are isolated from the periphery of a melanoma of human adult skin.…”

“…These integrins have receptor sites which exhibit domains for the specific proteins in the extracellular matrix (ECM) to bind. [2] After adhering, the cells aggregate to form clusters or focal adhesion (FA) sites/complexes which communicate with the outer and inner environment of the cell. Hence, a series of Tetracycline, an antibiotic used against a broad range of Gram positive and Gram negative bacteria was encapsulated in microspheres made of poly(3-hydroxybutyric acid) P(3HB), a microbial biodegradable polymer isolated from Bacillus cereus SPV.…”

“…multiple signaling complexes are formed which initiate the re-epithelization of a wound site. [2] The adherence of keratinocytes on a tissue engineering scaffold/biomaterial however depends on a number of factors such as the adsorption of proteins on the surface, the surface chemistry which influences the hydrophobicity, or hydrophilicity and the surface energy. Protein adsorption is the first step involved in establishing integration between the biomaterial and the biological environment.…”

“…Due to this, the ligand binding for specific cells can also be affected. Moreover, Bush et al [2] have used functionalized self-assembled monolayers (SAM) to engineer the surface chemistry so that the adsorption and the conformation of the protein can be modulated. Here, the surface densities were varied and the FN adsorption was seen to directly correlate with the changes in the keratinocyte attachment, spreading, and differentiation.…”

“…Following this, a change in the cell phenotype from fibroblasts to osteoblasts was observed when a smooth surface was changed to a rough surface. [2] Polyhydroxyalkanoates (PHAs) are polyesters of 3, 4, 5, and 6-hydroxyalkanoic acids. PHAs are highly biocompatible and biodegradable polyesters accumulated within bacteria under nutrient limiting conditions.…”