Phytic Acid Doped Polypyrrole as a Mediating Layer Promoting Growth of Prussian Blue on Cotton Fibers for Solar-Driven Interfacial Water Evaporation

Phytic acid doped polypyrrole (PPy) as a mediating layer was in-situ coated on cotton fibers (CFs) to promote the growth of Prussian blue (PB) and construct the PB/PPy@CFs composite. The results showed that the proper amounts of PA doped PPy in-situ generated significantly promoted the growth of PB on CFs, the PB deposition ratio increased from 12.29% (PB@CFs) to 32.4% (PB/PPy@CFs), and the growth of PB on PPy@CFs could be completed in 4 h. Scanning electron microscopy (SEM) showed that the PB particles with perfect nano cubic structure were formed in the composite. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) showed that both PB and PPy were successfully deposited on CFs. The PB/PPy@CFs composite had excellent light absorption, hydrophilicity, wettability, and photothermal property, and the surface could be heated up to 81.5 °C under one sun illumination. The PB/PPy@CFs composite as a photothermal conversion material was used for solar-driven interfacial water evaporation, the water evaporation rate was 1.36 kg·m−2·h−1 at the optical concentration of 1 kW·m2, and the corresponding photothermal conversion efficiency increased from 81.69% (PB@CFs) to 90.96% (PB/PPy@CFs).

Development of Photothermal Membrane for Treatment of Infected Wound: A Proof-of-Concept

Wound infection is a serious issue because of multi-drug resistance bacteria, thus developing an advanced therapy is a needed demand. Photothermal therapy (PTT) is a novel noninvasive strategy that utilizes PTT agents to convert near-infrared (NIR) light energy into heat to kill living cells. In this work, we developed the PTT agent containing membrane to treat the wound infection for the first time. Palladium nanoparticles (PdNPs) were chosen as PTT agents owing to their high stability, good biocompatibility, excellent photothermal property, and simple-green preparation. Chitosan (CS) has been widely studied in tissue engineering due to its good properties such as biocompatible, biodegradable, antibacterial, and wound-healing abilities. However, the poor workability and high brittleness of CS limit the applications of CS in tissue engineering. Thus, we combined polyvinyl alcohol (PVA) and CS to have the membrane with high flexibility, wettability, highly porosity. The test on cells showed that the membrane has high biocompatibility. The combination of PdNPs loading CS/PVA membrane and laser irradiation killed most of the bacteria in vitro.