Sulfadiazine Residue Rapid Test Strip (Tissue)

Hydroxyapatite/silver/silver sulfadiazine ternary nanocomposite (HAP/Ag/SSD TNC) with a novel hierarchical structure was successfully fabricated as following steps. First, mesoporous hydroxyapatite (HAP) nanorods as carrier were synthesized by a facile hydrothermal method. Second, as one antibacterial agent, silver nanoparticles were designed to be loaded on the mesoporous HAP nanorods to produce HAP/silver nanorods. Third, silver sulfadiazine as the other antibacterial agent was in situ produced on the surface of HAP/silver nanorods to form HAP/Ag/SSD TNC. To estimate its antibacterial properties, minimum inhibitory concentration, minimal bactericidal concentration, and a filter paper inhibition zone experiments were conducted with three bacteria strains of gram-negativeEscherichia coli(E. coli),Pseudomonas aeruginosa(P. aeruginosa), and gram-positiveStaphylococcusaureus(S. aureus). The results demonstrated that HAP/Ag/SSD TNC exhibited outstanding and sustained antibacterial activities againstP. aeruginosain 48 h. TowardE. coliandS. aureus, HAP/Ag/SSD TNC displayed similar antibacterial abilities with that of HAP/silver nanorods. Therefore, HAP/Ag/SSD TNC has the potential to be a new excellent antibacterial agent and extensively applied in the antibacterial field.

Shortage of face masks is a current critical concern since the emergence of coronavirus-2 or SARS-CoV-2 (COVID-19). In this work, we compared the melt-blown (MB) filter, which is commonly used for the N95 face mask, with nanofiber (NF) filter, which is gradually used as an effective mask filter, to evaluate their reusability. Extensive characterizations were performed repeatedly to evaluate some performance parameters, which include filtration efficiency, airflow rate, and surface and morphological properties, after two types of cleaning treatments. In the first cleaning type, samples were dipped in 75% ethanol for a predetermined duration. In the second cleaning type, 75% ethanol was sprayed on samples. It was found that filtration efficiency of MB filter was significantly dropped after treatment with ethanol, while the NF filter exhibited consistent high filtration efficiency regardless of cleaning types. In addition, the NF filter showed better cytocompatibility than the MB filter, demonstrating its harmlessness on the human body. Regardless of ethanol treatments, surfaces of both filter types maintained hydrophobicity, which can sufficiently prevent wetting by moisture and saliva splash to prohibit not only pathogen transmission but also bacterial growth inside. On the basis of these comparative evaluations, the wider use of the NF filter for face mask applications is highly recommended, and it can be reused multiple times with robust filtration efficiency. It would be greatly helpful to solve the current shortage issue of face masks and significantly improve safety for front line fighters against coronavirus disease.