The main objective of the project is to increase knowledge in the field of surface functionalization of electrospun polymer nanofibers using natural polymers such as collagen. This is an attractive alternative to the traditional method of nanofibers formation from solutions containing mixtures of natural and synthetic polymers, requiring the use of highly toxic solvents. The specific objectives are the systematic investigations of the effect of surface functionalization conditions on the efficiency of the process itself, the final structure of the fibers and their properties, in particular comparison of cells behavior in vitro conditions for nonwovens - scaffolds after the process of surface functionalization and those formed by electrospinning using polymer blends. As a result, optimization of surface functionalization conditions of nanofibers from a perspective of tissue engineering application will be obtained.
Hypothesis: Determination of the optimum conditions for carrying out the surface functionalization of nanofibers from synthetic polymers would provide scaffolds with unique functionality for applications in tissue engineering. An important element to increase the bioactivity and the regenerative potential of such materials in relation to traditional nonwovens formed from solutions of blends of synthetic and natural polymers, is related to the maintaining of the native structure of collagen with high biological activity, by eliminating from the electrospinning process of the solvents having strong toxicity and denaturing activity.
The investigations are divided into four parts:
The first step is the formation of polycaprolactone (PCL) nanofibers by electrospinning from solutions intended for further functionalization, as well as of the reference material - the classic bicomponent PCL/collagen fibers. The processing and material parameters established during the previous work carried out in our group are applied.
The second step is surface functionalization by s.c. wet chemical methods, consisting of two sub-steps - the aminolysis of alternatively - hydrolysis, and then immobilization of gelatin on the surface of the nanofibers using a crosslinking agent. Both stages are carried out in a wide range of processing and material parameters.
The third stage is a comprehensive study of the structure and selected properties of the fibers after each stage of functionalization. They include investigations of morphology, the concentration of amino, and carboxyl groups as well as gelatin molecules on the fiber surface, analysis of polymer molecular weight, molecular and supermolecular structure as well as mechanical properties and wettability.
The last stage includes biological investigations in vitro conditions in order to determine the degree of cytotoxicity of scaffolds and activity of cells grown on nonwovens (cell morphology, degree of flattening, adhesion, proliferation, and mitochondrial activity as a function of time).
In this publication, we present results of surface functionalization using aminolysis reaction: Jeznach O., Kołbuk D., Sajkiewicz P., Aminolysis of various aliphatic polyesters in a form of nanofibers and films, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym11101669, Vol.11, No.10, pp.1669-1-16, 2019
