Atmospheric pressure cold plasma versus wet-chemical surface treatments for carboxyl functionalization of polylactic acid: A first step toward covalent immobilization of bioactive molecules

• Published in: Colloids and surfaces, B, Biointerfaces Vol. 189; p. 110847
• Main Authors: Durán, Iván Rodríguez, Vanslambrouck, Stéphanie, Chevallier, Pascale, Hoesli, Corinne A., Laroche, Gaétan
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.05.2020
• Subjects: Atmospheric Pressure; Covalent immobilization; Dielectric barrier discharge; Hydrophobic and Hydrophilic Interactions; Molecular Structure; Particle Size; Plasma Gases - chemistry; Polyesters - chemistry; Polylactic acid; Surface characterization; Surface functionalization; Surface Properties; Wettability; Surface functionalization; Dielectric barrier discharge; Covalent immobilization; Surface characterization; Polylactic acid
• ISSN: 0927-7765; 1873-4367
• DOI: 10.1016/j.colsurfb.2020.110847

[Display omitted] •Carboxyl functionalization by plasma, diazonium, and alkali hydrolytic treatments.•Chemical changes in PLA samples are evaluated by contact angle measurements and XPS.•TBO assay reveals an increase in surface density of carboxyl groups in treated PLA.•Topographical analysis shows that plasma treatment causes no damage to PLA surface.•Fluorescent labeling demonstrates the availability and reactivity of carboxyl groups. The use of polylactic acid (PLA) has attracted growing interest, particularly in recent years, for biomedical applications because of its mechanical properties, biocompatibility, and biodegradability. Despite this, features such as surface hydrophobicity and the absence of suitable functional groups for covalent immobilization of bioactive molecules, make it challenging to endow PLA-based medical devices with additional features and thus broaden their range of applicability. In the present study, we demonstrate the suitability of atmospheric pressure dielectric barrier discharges operating in the Townsend regime as a promising alternative to other surface treatments, such as diazonium and alkali hydrolytic treatments, for carboxyl functionalization of PLA. Chemical changes in PLA surfaces are evaluated by contact angle measurements and by X-ray photoelectron spectroscopy while physical changes are investigated by scanning electron microscopy and atomic force microscopy. The amount of carboxyl groups generated on PLA surfaces is assessed by toluidine blue O assay and substantiated by grafting, through carboxyl groups, a fluorescent probe containing amino functionalities. All of the surface treatments have proven to be very effective in generating carboxylic groups on the PLA surface. Nevertheless, plasma treatment is shown to not degrade the PLA surface, in sharp contrast with diazonium and alkali hydrolytic treatments.