Poly-3-hydroxybutyrate (PHB) films were plasma-treated using pure NH 3 , pure Ar or mixtures of the two different proportions (20%, 30%, 40%, 50%, 70% NH 3 in Ar). Surface chemistry and surface topography changes of PHB films were observed after plasma processing in all plasma regimes. The XPS results confirmed the absence of chemical modification in the case of pure Ar plasma treatment. Nitrogen-containing groups (e.g., N-C=O) were detected on the surfaces of P3HB films treated with NH 3 -containing plasma. The surfaces of the untreated P3HB films were hydrophobic, and plasma treatment turned the surfaces hydrophilic, irrespective of the treatment.A significant decrease in the contact angle and an increase in the free surface energy were observed. An insignificant surface ageing effect was observed when P3HB samples were exposed to air for 10 days. In NIH 3T3 mice fibroblast cells, cell adhesion was significantly improved after plasma treatment in an Ar atmosphere, which is likely related to the fact that there was a surface ξ potential of 88.6 mV at neutral pH, causing a cleavage of the polymer chains and an increase in surface roughness.
Porous films have been prepared from degradable polymers—poly-3-hydroxybutyrate (PHB), poly-ε-caprolactone (PCL) and a blend of these polymers (1:3)—by adding porogen (camphor) to the polymer solution at 10%, 30% or 50% of the total mass of the polymer and porogen, and leaching it out afterwards. After the rinse, camphor content in films decreased to about 0.025%. The structure, physical/mechanical and biological properties of the films were investigated as dependent on their composition and porosity, which varied depending on the amount of camphor added. The surface of PHB films was porous, the PCL films were relatively smooth, and the PHB/PCL films had an intermediate structure. The addition of camphor increased the thickness (from 35 to 45 µm, from 40 to 80 µm and from 20 to 65 µm for PHB, PCL and PHB/PCL, respectively) and porosity (from 4.2(±3.6)% to 50.0(±12.8)%, from 6.4(±5.5)% to 54.5(±6.0)% and from 4.9(±4.8)% to 51.5(±5.8)%, respectively) of the films. The introduction (and removal) of 10% camphor into the PHB and PHB/PCL films led to an approximately twofold increase in the polar component of the free surface energy (from 5.4 ± 0.38 to 11.8 ± 1.33 and from 2.7 ± 0.13 to 5.2 ± 0.09 mN/m, respectively) but in other cases, on the contrary, a decrease in this indicator was registered. The increase of camphor addition from 0% to 50% gradually impaired mechanical properties of the films: so, Young’s modulus decreased from 3.6 to 1.8 GPa, from 0.30 to 0.12 GPa and from 0.50 to 0.20 GPa for PHB, PCL and PHB/PCL, respectively. At the same time, the water vapor transmission rate considerably increased from 197.37 ± 23.62 to 934.03 ± 114.34 g/m2/d for PHB films; from 1027.99 ± 154.10 to 7014.62 ± 280.81 g/m2/d for PCL films; and from 715.47 ± 50.08 to 4239.09 ± 275.54 g/m2/d for PHB/PCL films. Results of biocompatibility testing in the culture of NIH 3T3 mouse fibroblast cells showed that for the most of experimental samples cell adhesion and proliferation were comparable or superior to the corresponding parameters on the initial nonporous films. The best results were obtained for PHB films where at Day 3 of the experiment the registered cell density for experimental samples arrived at 2.66(±0.26) × 105 cells/cm2 versus 1.29(±0.33) × 105 cells/cm2 in the control. So, the proposed method can be used to construct highly porous cell scaffolds for cellular engineering.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.