The effects of the low-temperature plasma exposure, gg irradiation, and combined γ irradiation and plasma exposure on the structure and surface properties of thin films based on polylactic acid (PLA) are studied. Films are prepared by the solvent casting method. It is shown that films based on polylactic acid have topographically different sides: a smoother inner side and an embossed outer one. PLA films have properties close to hydrophobic ones, with a contact angle in the range of 70°–73° regardless of the surface side. They belong to weakly polar materials. The combined effect of plasma and gg irradiation slightly changes the surface topography. The effect of low-temperature plasma on the surface of the films leads to a decrease in the contact angle by 13°–55° (9–11%) and an increase in the surface energy due to the polar component. The results of in vivo experiments on rabbits are presented. Biomicroscopy, optical coherence tomography, and morphological and electron microscopic examination of the cornea after implantation of the initial and radiation- and plasma-treated films show that implantation of the films in the anterior chamber is not accompanied by a pronounced inflammatory reaction and increased intraocular pressure, while maintaining the morphological structure of the cornea almost unchanged.
1 March 2020 in Inorganic Materials: Applied Research
This paper presents data on the effects of steam sterilization on the properties of thin films based on polylactic acid. It has been established that thin films based on polylactic acid and poured from solutions of 10, 20, and 30 g have two topographically different sides. One side (internal) has a more prominent surface. The other side (external) has a smooth surface. It is reflected in the roughness parameters. Ra of the internal side varies from 0.01 to 0.018 μm. Ra of the external side is 0.17–0.4 μm. The average roughness increases from 0.17 to 0.4 μm with an increase in the mass of the solution poured into films. Sterilization contributes to a change in the surface of the polylactic acid films and makes their profile more prominent. This leads to a significant increase in the roughness of both sides by more than 5 times. In addition, it was found that thin polylactic acid films have hydrophobic (θ = 80°) properties. Steam sterilization reduces the wetting angle by 14°–15° (17–18%) and increases the surface energy values to a greater extent owing to the polar component. These changes increase the hydrophilicity of the studied material.
Adapting biological systems for nanoparticle synthesis opens an orthogonal Green direction in nanoscience by reducing the reliance on harsh chemicals and energy-intensive procedures. This study addresses the challenge of efficient catalyst preparation for organic synthesis, focusing on the rapid formation of palladium (Pd) nanoparticles using bacterial cells as a renewable and eco-friendly support. The preparation of catalytically active nanoparticles on the bacterium Paracoccus yeei VKM B-3302 represents a more suitable approach to increase the reaction efficiency due to its resistance to metal salts. We introduce an efficient method that significantly reduces the preparation time of Pd nanoparticles on Paracoccus yeei bacteria to only 7 min, greatly accelerating the process compared with traditional methods. Our findings reveal the major role of live bacterial cells in the formation and stabilization of Pd nanoparticles, which exhibit high catalytic activity in the Mizoroki–Heck reaction. This method not only ensures high yields of the desired product but also offers a greener and more sustainable alternative to conventional catalytic processes. The rapid preparation and high efficiency of this biohybrid catalyst opens new perspectives for the application of biosupported nanoparticles in organic synthesis and a transformative sustainable pathway for chemical production processes.