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.

Extraction and preconcentration of tylosin from milk samples through functionalized TiO2 nanoparticles reinforced with a hollow fiber membrane as a novel solid/liquid-phase microextraction technique.

The aim of this study was to introduce a novel, simple, and highly sensitive preparation method for determination of tylosin in different milk samples. In the so-called functionalized TiO2 hollow fiber solid/liquid-phase microextraction method, the acceptor phase is functionalized TiO2 nanoparticles that are dispersed in the organic solvent and held in the pores and lumen of a porous polypropylene hollow fiber membrane. An effective functionalization of TiO2 nanoparticles has been done in the presence of aqueous H2 O2 and a mild acidic ambient under UV irradiation. This novel extraction method showed excellent extraction efficiency and a high enrichment factor (540.2) in comparison with conventional hollow fiber liquid-phase microextraction. All the experiments were monitored at λmax = 284 nm using a simple double beam UV-visible spectrophotometer. A Taguchi orthogonal array experimental design with an OA16 (4(5) ) matrix was employed to optimize the factors affecting the efficiency of hollow fiber solid/liquid-phase microextraction such as pH, stirring rate, salt addition, extraction time, and the volume of donor phase. This developed method was successfully applied for the separation and determination of tylosin in milk samples with a linear concentration range of 0.51-7000 µg/L (r(2) = 0.991) and 0.21 µg/L as the limit of detection.