Cu nanoparticles grafting on the surface of ZnO nanostructures to boost the porosity and surface area for effective removal of manganese ions from aqueous solutions.

Designing highly adsorptive materials for wastewater treatment via facile approaches is still challenging. To boost the recovery of heavy metals from wastewater, surface and structure modification are considered a successful route. Herein, we report the design of ZnO nanoparticles by a simple thermal decomposition method followed by grafting Cu nanoparticles (Cu NPs) over the ZnO surface. Cu/ZnO was prepared with different Cu ratios, 0.01 and 1%. It was found that incorporating Cu into ZnO improved the porosity and surface area of ZnO. The adsorption ability of Cu/ZnO compared with bare ZnO was studied towards removing manganese ions from wastewater. The effects of several parameters, such as pH, temperature, contact time, and initial ion concentrations, were studied. The maximum removal of manganese was found at pH 2, 20 °C after 60 min in the presence of 1 g/L adsorbent. The role of Cu grafted on the surface of ZnO was discussed. The rates of adsorption were found to follow the pseudo-second-order model. The results showed better fitting to Freundlich isotherm. The thermodynamic study revealed that the sorption process is spontaneous, exothermic, and favorable at low temperatures. The free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) changes were calculated to predict the nature of adsorption.

The Use of Photoactive Polymeric Nanoparticles and Nanofibers to Generate a Photodynamic-Mediated Antimicrobial Effect, with a Special Emphasis on Chronic Wounds.

This review is concerned with chronic wounds, with an emphasis on biofilm and its complicated management process. The basics of antimicrobial photodynamic therapy (PDT) and its underlying mechanisms for microbial eradication are presented. Intrinsically active nanocarriers (polydopamine NPs, chitosan NPs, and polymeric micelles) that can further potentiate the antimicrobial photodynamic effect are discussed. This review also delves into the role of photoactive electrospun nanofibers, either in their eluting or non-eluting mode of action, in microbial eradication and accelerating the healing of wounds. Synergic strategies to augment the PDT-mediated effect of photoactive nanofibers are reviewed.

Photoactive electrospun cellulose acetate/polyethylene oxide/methylene blue and trilayered cellulose acetate/polyethylene oxide/silk fibroin/ciprofloxacin nanofibers for chronic wound healing.

This study aimed to synthesize cellulose acetate (CA)-based electrospun nanofibers as drug delivery dressings for chronic wound healing. For the first time, CA was blended with polyethylene oxide (PEO) using acetone and formic acid. Methylene blue (MB) was incorporated into monolayered random CA/PEO nanofibers. They had a diameter of 400-600 nm, were hydrophilic, and generated reactive oxygen species upon irradiation. Thus, they mediated antimicrobial photodynamic inactivation (aPDI) against isolated biofilm-forming Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Bacterial survival, biofilm mass, and produced pyocyanin of the treated groups declined by 90%, 80%, and 3 folds, respectively. On the other hand, ciprofloxacin (Cipro) was loaded into an innovative trilayered aligned nanofiber consisting of CA/PEO surrounding a blank layer of silk fibroin. Cipro and MB release followed the Korsmeyer-Peppas model. An infected diabetic wound mouse model was established and treated with either MB-aPDI or Cipro. A combined therapy group of MB-aPDI followed by Cipro was included. The combined therapy showed significantly better results than monotherapies delineated by elevation in re-epithelization, collagen deposition, CD34, and TGF-ß expression, along with a decline in CD95+ cells. This study deduced that drug-loaded CA electrospun nanofibers might be exploited in multimodal chronic wound healing.