Development of New Collagen/Clay Composite Biomaterials

Abstract

The fabrication of collagen-based biomaterials for skin regeneration offers various challenges for tissue engineers. The purpose of this study was to obtain a novel series of composite biomaterials based on collagen and several types of clays. In order to investigate the influence of clay type on drug release behavior, the obtained collagen-based composite materials were further loaded with gentamicin. Physiochemical and biological analyses were performed to analyze the obtained nanocomposite materials after nanoclay embedding. Infrared spectra confirmed the inclusion of clay in the collagen polymeric matrix without any denaturation of triple helical conformation. All the composite samples revealed a slight change in the 2-theta values pointing toward a homogenous distribution of clay layers inside the collagen matrix with the obtaining of mainly intercalated collagen-clay structures, according X-ray diffraction analyses. The porosity of collagen/clay composite biomaterials varied depending on clay nanoparticles sort. Thermo-mechanical analyses indicated enhanced thermal and mechanical features for collagen composites as compared with neat type II collagen matrix. Biodegradation findings were supported by swelling studies, which indicated a more crosslinked structure due additional H bonding brought on by nanoclays. The biology tests demonstrated the influence of clay type on cellular viability but also on the antimicrobial behavior of composite scaffolds. All nanocomposite samples presented a delayed gentamicin release when compared with the collagen-gentamicin sample. The obtained results highlighted the importance of clay type selection as this affects the performances of the collagen-based composites as promising biomaterials for future applications in the biomedical field.

Keywords: biomaterials; clay; type II collagen.

Scheme 1

Schematic structures of the different types of mineral clays.

Figure 1

FTIR spectra of the obtained collagen/clay composite biomaterials.

Figure 2

X-ray diffraction patterns of composite samples.

Figure 3

SEM images of collagen/clay composite biomaterials (250×) and calculated average pore diameter with standard deviation.

Figure 4

TGA curves of collagen/clay composite biomaterials.

Figure 5

Equilibrium swelling degree of collagen-based samples (ns p > 0.05, ** p ≤ 0.01).

Figure 6

Biodegradation degree as function of time for the composite samples: (a). third day; (b). 7th day, (c). 17th day; (d). 50th day (ns p > 0.05, * p ≤ 0.05, ** p ≤ 0.01).

Figure 7

DMA mechanical properties of dried collagen/clay composite biomaterials.

Figure 8

DMA stress–strain curves for the collagen/clay composite hydrogels swollen in PBS.

Figure 9

Gentamicin release profile as a function of time.

Figure 10

Antimicrobial activity against Escherichia coli and Staphylococcus aureus.

Figure 11

Biological evaluation of the obtained samples, *** p ≤ 0.001.

Figure 12

Obtained collagen/clay composite biomaterials (without gentamicin).