Atmospheric pressure plasma assisted immobilization of hyaluronic acid on tissue engineering PLA-based scaffolds and its effect on primary human macrophages

Bioactive polylactic acid based (PLA) scaffolds with hyaluronic acid immobilized on their surface by atmospheric pressure plasma assisted modification method were developed. By using X-ray photoelectron spectroscopy and wettability measurements it was shown that atmospheric pressure plasma treatment leads to the changes in surface chemical composition of the PLA-based scaffolds that resulted in an increased long-term hydrophilicity of the scaffolds surface. Scanning electron microscopy and mechanical studies revealed that the use of plasma for surface activation allows for the non-destructive immobilization of bioactive compounds like hyaluronic acid. The modified PLA-based scaffolds effect on the release of cytokines and matrix metalloproteinases by primary human monocyte-derived macrophages was investigated. The macrophages reaction to the scaffolds was donor-specific, however, the two best materials from immunological point of view were identified - plasma treated PLA-based scaffold and PLA-based scaffold with the least amount of immobilized hyaluronic acid. Both hyaluronic acid attachment and atmospheric pressure plasma treatment enhance PLA-based scaffolds biocompatibility. It was found that supernatants collected after the macrophages coculture with modified PLA-based scaffolds stimulate HUVECs' tube formation. The modified PLA-based scaffolds possess pro-angiogenic activity. Thus, our research offers a high-performing method for the creation of polymer-based tissue engineering scaffolds with modified bioactive surface. Keywords: Polylactic acid (PLA), Hyaluronic acid (HA), Tissue engineering scaffold (TES), Plasma, Macrophages, Cytokines