Profiling of the antibacterial activity of a hypothetical surface containing Ag and Cu nanoparticles using the finite difference method

• Main Authors: Morales, Alyza Claire A., Necio, Marie Danielle S., Pabale, Sofia Isabelle D.
• Format: text
• Language: English
• Published: Animo Repository 2022
• Subjects: Nanoparticles—Microbiology; Chemical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etdb_chemeng/12; https://animorepository.dlsu.edu.ph/cgi/viewcontent.cgi?article=1015&context=etdb_chemeng
• Institution: De La Salle University

Metal nanoparticles, such as silver and copper nanoparticles (Ag and Cu NPs), have antibacterial properties that inhibit the growth of bacterial strains. Incorporating these nanoparticles on material surfaces increases the overall property and performance of the material. However, profiling the antibacterial activity of Ag and Cu NPs, in terms of their location and duration, using mathematical models is yet to be developed. Thus, the purpose of this study is to investigate the antibacterial activity of Ag and Cu NPs on theoretical surfaces against the S. aureus bacteria using the finite difference method (FDM). The Ag to Cu metal loadings, with ratios of 1:0, 0:1, 2:3, 3:2, 1:2, 2:1, 1:1, 1:3, and 3:2, that achieved zones with 90% inhibition of the bacteria (IZ-90) for 25 %, 50 %, and 75 % area coverage and their optimum ratios were determined. The researchers developed a code incorporating FDM in Visual Basics for Applications (VBA) in MS Excel software to generate a 2D hypothetical matrix that profiles the antibacterial activity of Ag and Cu NPs. With that, this study may contribute to the future use and development of nanoparticles since the antibacterial activity of Ag and Cu NPs on surfaces was predicted without conducting any physical experiments. Different configurations of Ag and Cu NPs were simulated on the matrices to attain the target IZ-90 area coverages. The average surface inhibition rate (ASIR) and minimum local element inhibition rate for each test case were identified based on the simulations to determine the optimal Ag to Cu ratios. The Ag and Cu NPs placements and number of particles play a huge role in increasing or decreasing the IZ-90 coverage area of the matrix. A greater amount of Ag NPs requires a lesser number of particles on the matrices as they have a larger IZ-90 diameter than Cu NPs. The optimal Ag to Cu ratios obtained were based on matrices with high average surface and minimum local element inhibition rates. The time of inhibition and fatality rate of the optimal ratios were then obtained. Based on the observations, the optimal Ag to Cu ratios are 1:2, 1:2, 1:3 for 25 %, 50 %, 75 % area coverage, respectively.