Abstract
For the creation of scaffolds in tissue engineering applications, it is essential to control the physical morphology of fibres and to choose compositions which do not disturb normal physiological function. Collagen, the most abundant protein in the human body, is a well-established biopolymer used in electrospinning compositions. It shows high in-vivo stability and is able to maintain a high biomechanical strength over time. In this study, the effects of collagen type I in polylactic acid-drug electrospun scaffolds for tissue engineering applications are examined. The samples produced were subsequently characterised using a range of techniques. Scanning electron microscopy analysis shows that the fibre morphologies varied across PLA-drug and PLA-collagen-drug samples − the addition of collagen caused a decrease in average fibre diameter by nearly half, and produced nanofibres. Atomic force microscopy imaging revealed collagen-banding patterns which show the successful integration of collagen with PLA. Solid-state characterisation suggested a chemical interaction between PLA and drug compounds, irgasan and levofloxacin, and the collagen increased the amorphous regions within the samples. Surface energy analysis of drug powders showed a higher dispersive surface energy of levofloxacin compared with irgasan, and contact angle goniometry showed an increase in hydrophobicity in PLA-collagen-drug samples. The antibacterial studies showed a high efficacy of resistance against the growth of both E. coli and S. Aureus, except with PLA-collagen-LEVO which showed a regrowth of bacteria after 48h. This can be attributed to the low drug release percentage incorporated into the nanofibre during the in vitro release study. However, the studies did show that collagen helped shift both drugs into sustained release behaviour. These ideal modifications to electrospun scaffolds may prove useful in further research regarding the acceptance of human tissue by inhibiting the potential for bacterial infection.
Highlights
The 1H NMR spectrum of polylactic acid doped with 0.1% levofloxacin showed no difference in the NMR parameters of the polymer; the peaks of levofloxacin were detected at the expected chemical shift ranges, these signals appeared with too low SNR to be useful for further measurements
It can only be inferred from the NMR measurements that a possible presence of intermolecular interaction between polylactic acid and levofloxacin does not bring about detectable changes in the 1H NMR spectra
The addition of collagen caused an overall decrease in fibre morphology and average fibre diameter across both sets of drugs, irgasan and levofloxacin, with nanofibers forming in the PLAcollagen-LEVO samples
Summary
I.J. Hall Barrientos et al / International Journal of Pharmaceutics 531 (2017) 67–79 undergo a primary hyper-proliferative stage, characterised by clot formation and the recruitment of inflammatory cells (macrophages) into the wound (Koh and DiPietro, 2011). Secretion of local tissue mediators encourages cell migration and begins the process of scar formation (Hu et al, 2014). A result of tissue remodelling, increases the tensile strength of skin across lesions and increases (or decreases) the risk of ruptures. The tissue is open to infection itself and as a pathway into deeper tissue structures. The purpose of an added matrix task may be to provide tensile strength, to encourage controlled epithelialisation and new vascular growth and to decrease the formation of bacterial biofilms. The fabrication of scaffolds for wound repair has become important, especially the formation of tissue-specific scaffolds (van Winterswijk and Nout, 2007)
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