Gold nanoparticles’ concentration dependent reactivity to alendronate, memantine, and tobramycin

Abstract

Turkevich Gold nanoparticles are the original nanoparticles that have been modified over time. Combining nanoparticles with targeting medications such as alendronate, memantine, and tobramycin will provide additional benefits in targeting specific areas in the bone, brain, and microorganisms, respectively. The reactivity and stability of nanoparticles in the presence of various drug concentrations (micro-, nano-, and milli-levels) have been studied. The absorbance spectra of nanoparticles at λmax 520 nm were always stable with alendronate, whereas with memantine and tobramycin, the spectra were unchanged (no color change) in the nano- level over twenty minutes and red shifts (color change) occurred in the micro-level. High Resolution Transmission Electron Microscopy (HRTEM) and Dynamic light scattering (DLS) revealed that the core diameter was relatively stable in all cases, whereas the hydrodynamic diameter and zeta potential varied with drug concentration. Increasing concentration increased hydrodynamic diameter slightly with memantine (from 64.99 to 98.41 nm), dramatically with tobramycin (from 135.3 to 332.16 nm), and almost negligibly with alendronate (from 52.08 to 58.94 nm). Zeta potential, conversely, is reduced as concentration increases. Memantine had the greatest reduction in negativity, followed by tobramycin, but alendronate had a slight increase in negativity. This research would be useful for the application of gold nanoparticles in targeted drug delivery, where stability and reactivity of gold nanoparticles are critical.