Effect of surface modification of polylactides on fibroblasts L-929 and osteoblasts MG-63

During the past few years, tissue engineering has become one of the most promising techniques to maintain, improve, or reconstruct human tissue, even complete human organs. This solution is frequently based on the realization of temporary porous matrices, also called "scaffolds", design as model and structure for the development of cells. Surface properties of those biomaterials are some determinant criteria for cell adhesion and proliferation.
The scope of this work is the study of adhesion and proliferation of fibroblasts L-929 and osteoblasts MG-63 on untreated, hydrolyzed or aminolyzed polylactides. First, these substrates are developed: poly-L,D-lactide (PDLLA) powder is pressed into disks. The surface of disks was chemically modified by hydrolysis and aminolysis surface treatments. Surface modifications were based on previous studies. [1,2] The hydrolysis process is carried out by immersing PDLLA disks in 2 M NaOH for 20 min at room temperature (24°C) under constant agitation. The aminolysis process is performed by placing PDLLA disks in 15 % ethylenediamine in isopropanol for 5 min at room temperature (24°C) under constant agitation. Substrates are characterized by optical microscopy, Scanning Electron Microscopy and water contact angle. Finally, cell adhesion, proliferation, and viability on these substrates are assessed by cell counting and MTT assay after 1, 4, and 8 days of cell culture.
Results from surface characterization show an increase of roughness for hydrolyzed polylactide. Regarding water contact angle measurements, values are smaller on treated substrates even though the difference with untreated substrates appears smaller than expected in the literature. [1,2] Cell counting and MTT assay show an increase of cell proliferation and cell viability for treated polylactide substrates in the case of fibroblasts and a decrease of cell proliferation for aminolyzed polylactide substrates in the case of osteoblasts. In conclusions, this work highlights the different effects of surface modification on fibroblasts and osteoblasts viability.
References :
[1]. Wang YQ, Cai JY. Enhanced cell affinity of poly(L-lactic acid) modified by base hydrolysis: wettability and surface roughness at nanometer scale. Current Applied Physics 2007, 7(S1):e108–e111.
[2]. Lin Y, Chrzanowski W, Knowles J, Bishop A, Bismarck A. Functionalized poly(D,L-lactide) for pulmonary epithelial cell culture. Advanced Engineering Materials 2010, 12(4): B101–B112.