Marine collagen based membranes for cornea regeneration by electrospinning technique

In the past few years, the biomedical field have been battling to mimic the assembly of the extracellular matrix (ECM), component essential for structural and biochemical support to the cells and surrounding environment. In the past, the use of synthetic polymers to produce an ECM faced the limitation of their chemical and structural dissimilarities compared with natural materials. The chase for the perfect biomaterial has long been made and collagen arises as an essential key vector to the structure of ECM of animals. Collagen can be extracted from several sources. Up to now, bovine and porcine origin by-products are the common sources for the production of collagen in industrial context, but religious constraints and risks associated to diseases, like bovine spongiform encephalopathy (BSE), have demonstrated to be a serious disadvantage. Lately, numerous alternatives are being exploited, as by-products from marine origin (particularly fish skins), without the concerning that the mammals materials present.

Electrospinning is one of the most well established processes for producing nanofibrous membranes and a simple and attractive approach for the fabrication of a nanofiber collagen-based scaffold. Applying an appropriated high voltage to a liquid droplet of a polymer solution, it becomes charged and the electrostatic repulsion overcomes the surface tension causing the stretching of the droplet to a critical point that a fiber erupts and subsequently deposits onto a collector to obtain matrices. By playing with the experimental conditions, a hierarchical structure can be obtained. In this perspective, this work focuses on the electrospinning of marine origin collagen to produce a new biomaterial envisaging the regeneration of human cornea. This tissue is mainly composed by collagen fibers organized in a multilayered structure with orthogonal orientation of collagen fibers between adjacent layers.

Collagen has been extracted from Atlantic cod (Gadus morhua) skins and further characterized to assess its purity, aminoacid profile and denaturation temperature. Moreover, diverse experimental parameters associated with the processing by electrospinning are being varied, namely: solution properties (viscosity, conductivity, polymer molecular weight and dielectric constant); mechanical variables (material flow rate, electric field strength, distance between tip and collector, needle tip design, collector composition and geometry) and ambient conditions (temperature and humidity). The goal is to understand the effect of these experimental conditions on the production of nanofibrillar membranes, namely the fiber dimensions, cohesiveness and hierarchical features, aiming to ultimately mimic the cornea ECM structure.