Polyurethane foam-cadmium sulfide nanocomposite with open cell structure: Dye removal and antibacterial applications

A novel all-organic microcapsule with excellent long-term antibacterial and anti-corrosion performances

This work successfully synthesized the salicylic acid@polyurea-formaldehyde (SA@PUF) microcapsules with PUF microcapsules as shell material and SA as core material. The loading content of SA in the PUF microcapsules was approximately 40 %. The SA@PUF microcapsules had excellent long-term antibacterial properties because the PUF microcapsules controlled the release of SA antifouling agents with the ability to induce reactive oxygen species generation and inactivate bacteria. The antibacterial efficiency of SA@PUF microcapsules after 35 days against Staphylococcus aureus and Pseudomonas aeruginosa remained at 80 % and 81 %, increased by 60 % and 62 % compared with pure SA, respectively. The impedance modulus at 0.01 Hz of the SA@PUF coating reached 5.51 GΩ cm², much higher than blank coating (2.55 GΩ cm²) and PUF coating (4.94 GΩ cm²), indicating that the anti-corrosion property of the SA@PUF coating was much better. This work would contribute to developing novel coatings with long-term antibacterial activity and excellent anti-corrosion performance.

Ternary and Quaternary Nanocrystalline Cu-Based Sulfides as Perspective Antibacterial Materials Mechanochemically Synthesized in a Scalable Fashion

Twelve Cu-based ternary (Cu-Me₁-S, Me₁ = Fe, Sn, or Sb) and quaternary (Cu-Me₂-Sn-S, Me₂ = Fe, Zn, or V) nanocrystalline sulfides are shown as perspective antibacterial materials here. They were prepared from elemental precursors by a one-step solvent-free mechanochemical synthesis in a 100 g batch using scalable eccentric vibratory ball milling. Most of the products have shown strong antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria. For instance, stannite Cu₂FeSnS₄ and mohite Cu₂SnS₃ were the most active against E. coli, whereas kesterite Cu₂ZnSnS₄ and rhodostannite Cu₂FeSn₃S₈ exhibited the highest antibacterial activity against S. aureus. In general, stannite has shown the best antibacterial properties out of all the studied samples. Five out of twelve products have been prepared using mechanochemical synthesis for the first time in a scalable fashion here. The presented synthetic approach is a promising alternative to traditional syntheses of nanomaterials suitable for biological applications and shows ternary and quaternary sulfides as potential candidates for the next-generation antibacterial agents.

Natural Additives Improving Polyurethane Antimicrobial Activity

In recent years, there has been a growing interest in using polymers with antibacterial and antifungal properties; therefore, the present review is focused on the effect of natural compounds on the antibacterial and antifungal properties of polyurethane (PUR). This topic is important because materials and objects made with this polymer can be used as antibacterial and antifungal ones in places where hygiene and sterile conditions are particularly required (e.g., in healthcare, construction industries, cosmetology, pharmacology, or food industries) and thus can become another possibility in comparison to commonly used disinfectants, which mostly show high toxicity to the environment and the human health. The review presents the possibilities of using natural extracts as antibacterial, antifungal, and antiviral additives, which, in contrast to the currently used antibiotics, have a much wider effect. Antibiotics fight bacterial infections by killing bacteria (bactericidal effect) or slowing and stopping their growth (bacteriostatic effect) and effect on different kinds of fungi, but they do not fight viruses; therefore, compounds of natural origin can find wide use as biocidal substances. Fungi grow in almost any environment, and they reproduce easily in dirt and wet spaces; thus, the development of antifungal PUR foams is focused on avoiding fungal infections and inhibiting growth. Polymers are susceptible to microorganism adhesion and, consequently, are treated and modified to inhibit fungal and bacterial growth. The ability of micro-organisms to grow on polyurethanes can cause human health problems during the use and storage of polymers, making it necessary to use additives that eliminate bacteria, viruses, and fungi.

Starch-based polyurethane/CuO nanocomposite foam: Antibacterial effects for infection control

In the present study, a new method for the synthesis of the open cell flexible polyurethane foams (PUFs) was developed by using starch powder and the modification of closed cell foam formulation. Starch is the second largest polymeric carbohydrate as a macromolecule on this planet with a large number of glucose units. Copper oxide nanoparticles (CuO NPs) were synthesized by thermal degradation method at different temperatures of 400, 600 and 800 °C as antimicrobial agents. The antimicrobial activity of CuO NPs and commercial CuO powder against the main causes of hospital infections were tested. CuO₆₀₀ was the most effective antimicrobial agent and enhanced polymer matrix tensile strength with starch powder as new polyurethane foams (PUFs) cell opener with high tensile strength. The effects of parameters on tensile strength were optimized using response surface methodology (RSM). CuO NPs and PUF had optimal conditions and were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Foam synthesized at the optimal conditions had an open cell structure with high tensile strength and efficient antimicrobial activity that made them suitable to be used as an antimicrobial hospital mattress to control hospital infections.