Polyvinyl alcohol (pva)

Poly(N-hydroxyethyl acrylamide) (pHEAAm) was synthesized by thermally initiated radical polymerization (see Supplementary Materials). Poly(acrylic acid) (pAA, Mw = 5000) and poly(vinyl pyrrolidone) (pVP, Mw = 36,000) were purchased from FUJIFILM Wako Pure Chemical Corporation (Osaka, Japan) and Honeywell Fluka (Morristown, NJ, USA), respectively, and poly(ethylene glycol) (pEG, Mw = 20,000) and poly(vinyl alcohol) (pVA, Mw = 500) were purchased from Nacalai Tesque (Kyoto, Japan). In this study, three different aqueous dispersions of titanium oxide nanoparticles (TiNP-x) were used for fabricating polymer composites. TiNP-1 (40 nm, 0.85 wt%, PTA) and TiNP-2 (20 nm, 0.85 wt%, TPX-HP) were purchased from Kon Corporation (Saga, Japan), and TiNP-3 (70 nm, 18.1 wt%, TisolA) was kindly provided by NYACOL Nano Technologies Inc. (Ashland, MA, USA). Deionized water was prepared with an Elix UV 3 (Merck KGaA, Darmstadt, Germany) and used as a solvent.

PB: 50 mM sodium phosphate buffer (pH 7.3); PBS: PB containing 9.0 g/L NaCl; G-PBS: PBS containing 1.0 g/L gelatin; T-PBS: PBS containing 0.050% (v/v) Tween 20; M-PBS: PBS containing 20 g/L skim milk; PVG-PBS: G-PBS containing 1.0 g/L polyvinyl alcohol (average polymerization degree 500; Nacalai Tesque); PBS-2: 10 mM Na₂HPO₄, 1.8 mM KH₂PO₄, 0.14 M NaCl, 2.7 mM KCl (pH 7.4); M-PBS-2: PBS-2 containing 20 g/L skim milk; and T-PBS-2: PBS-2 containing 0.10% (v/v) Tween 20^{12 (link)–16 (link)}.

The commercially available titanium mesh used in this study was Jeil Titanium Mesh (Proseed Corporation, Tokyo, Japan). PLGA was purchased from Wako Pure Chemical Industries (Osaka, Japan). Dichloromethane and polyvinyl alcohol were purchased from Nacalai Tesque (Kyoto, Japan). FS was obtained from Toronto Research Chemicals (North York, Canada).
PLGA membrane loaded with or without FS was fabricated as described in a previous report [23 (link)]. In short, to prepare a single-phase solution, 2.4 g of PLGA was dissolved in 3 ml dichloromethane. The solution was then mixed without FS (PLGA group) or mixed with 24 mg of FS (PLGA–FS group). Then, the PLGA mixture was emulsified in polyvinyl alcohol with stirring to evaporate at 60°C for 3 days. The mixture was dropped onto silicone rubber, in order to ensure easy membrane removal, pressed using another silicone rubber on the mixture, and dried in a vacuum oven at 37°C for 1 day. To form the PLGA-layered TM, a TM was put between the two layers of PLGA. Then, the membrane was pressed and dried in an oven at 37°C for 1 day. The titanium-layered PLGA was divided into two groups: the TM–PLGA group and the TM–PLGA–FS group. The thicknesses of all membranes were measured at four points per piece of membrane using a digital micrometer (N = 5).