Green cinnamaldehyde and thymol modified zinc oxide with double synergistic antibacterial effects in polypropylene

Cinnamaldehyde-Contained Polymers and Their Biomedical Applications

Cinnamaldehyde, a natural product that can be extracted from a variety of plants of the genus Cinnamomum, exhibits excellent biological activities including antibacterial, antifungal, anti-inflammatory, and anticancer properties. To overcome the disadvantages (e.g., poor water solubility and sensitivity to light) or enhance the advantages (e.g., high reactivity and promoting cellular reactive oxygen species production) of cinnamaldehyde, cinnamaldehyde can be loaded into or conjugated with polymers for sustained or controlled release, thereby prolonging the effective action time of its biological activities. Moreover, when cinnamaldehyde is conjugated with a polymer, it can also introduce environmental responsiveness to the polymer through the form of stimuli-sensitive linkages between its aldehyde group and various functional groups of polymers. The environmental responsiveness provides the great potential of cinnamaldehyde-conjugated polymers for applications in the biomedical field. In this review, the strategies for preparing cinnamaldehyde-contained polymers are summarized and their biomedical applications are also reviewed.

Fabricating Antibacterial Polyethylene Terephthalate Substrates Through an Industrial Approach by Applying Emulsions of Copper-Based Nanoparticles

In this research, various emulsions of copper-based nanoparticles were synthesized through the chemical reduction method followed by utilizing the pad–dry–cure technique as an industrial approach to manufacturing bactericidal polyethylene terephthalate (PET) substrates. Copper sulfate/copper acetate, sodium hypophosphite (SHP)/ascorbic acid, and cetyltrimethylammonium bromide were employed as salts, reducing agents, and stabilizers, respectively. Also, a spin finish oil was used for forming an emulsion. The effects of type and amount of copper salt and reductant as well as the use of resin and stabilizer were investigated concerning antibacterial activities, weight, and color changes of coated samples to find optimum formulation. Field-emission scanning electron microscope (FESEM) images, mapping/energy-dispersive spectroscopy (EDX), X-ray diffraction (XRD) pattern, Raman spectroscopy, and UV–visible spectrophotometer was proved successful in synthesis and loading of copper-based emulsions on the PET substrates. The results revealed that change of copper salt, substituting SHP with ascorbic acid, the addition of resin, and the use of surfactant yielded negligible effect, enhancing impact, reducing the influence, and improving efficacy on bactericidal characteristics of the treated samples, respectively. Based on findings, the samples coated by emulsion containing only copper sulfate/SHP and emulsion including only copper acetate were considered optimum samples indicating 100% bactericidal properties against both S. aureus and E. coli pathogenic bacteria. Despite showing bactericidal activities, it was further found that the treated samples exhibited cell toxicity toward human skin cells implying their applications in indirect contact usages. Coated samples further indicated a good washing fastness even after 20 washing cycles. This route can be considered as a facile industrially applicable method for imparting bactericidal properties to polymeric substrates. Furthermore, such emulsions can potentially be consumed as an antibacterial spin finish oil in melt-spinning to develop antibacterial textiles.