Nanocoatings through Plasma Technology to Tailor the Chemical, Physicochemical, Mechanical, and Biological Properties of the Biomineralization Membrane

Nanocoatings for the biomineralization membrane were developed on a gelatin (Gel) and carbonated hydroxyapatite (CHA) composite, namely, Gel/CHA membrane. The membrane, which contains bioactive polymer and a mineral phase, was further modified using plasma to deposit thin functional polymeric films. These surface-tailored nanocoatings improved the membrane's performance by increasing its swelling capacity to better mimic a tissue-like environment, strengthening its mechanical stability during application, and modulating interactions with biological components such as proteins to support tissue engineering and regeneration. Four types of thin films were explored, namely, 2-methyl-2-oxazoline (OX), 1,7-octadiene, acrylic acid (AC), and allylamine (AA). The physicochemical, mechanical, and biological properties of these plasma-functionalized membranes were systematically investigated. Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) confirmed the successful deposition of functional coatings, while scanning electron microscopy (SEM) and atomic force microscopy demonstrated variations in the surface morphology and roughness. Water contact angle and swelling ratio measurements revealed tunable hydrophilicity and water uptake properties, with AC- and OX-coated membranes exhibiting enhanced hydration. Mechanical testing in dry state indicated that the OX-coated membranes achieved an optimal balance between tensile strength and elongation, thereby enhancing their mechanical resilience. Protein adsorption studies highlighted increased biomolecular interactions with hydrophobic surfaces demonstrating higher protein affinity. Cytocompatibility assessments, following ISO 10993-5:2009 standards, confirmed that all plasma-coated membranes were noncytotoxic to osteoblast MC-3T3-E1 cell lines, with cell viability exceeding 80%. The in vitro evaluation of MC-3T3-E1 cell adhesion was confirmed using DAPI staining and SEM observation and revealed that the MC3T3-E1 cells attached on control, AC, and AA membranes with a flatter shape. Additionally, the mineralization potential was assessed via simulated body fluid immersion for up to 360 min. EDX analysis showed time-dependent deposition of calcium and phosphate, with AA-coated membranes exhibiting the highest mineral accumulation. These findings demonstrate that plasma-assisted functionalization can significantly improve the membrane properties, making it a promising candidate for advanced bone tissue engineering applications.