Enhanced sensitivity in tobramycin monitoring using a surfactant-aligned liquid crystal aptasensor with a ternary hybrid aptamer

Abstract

Determining pharmaceutical residues in foodstuffs is of great importance worldwide. The improper use of tobramycin (TOB) with abroad spectrum antibacterial activity results in its accumulation in the food chain and human body. Given its detrimental effects on human health, the careful surveillance of TOB concentrations is essential to ensure food safety. Presented here is a highly sensitive aptasensing array designed to measure the TOB concentration by disrupting the alignment of liquid crystal (LC) molecules induced by surfactants. For the first time, a ternary hybrid of the aptamer strands was incorporated onto the surfactant-designed LC-aqueous interface instead of a single strand of aptamer, causing a significant disruption in the customary orientation of LCs. This changed the brightness quantity from 35.06 to 69.54, due to higher interaction with the positively charged section of the surfactant than that for one aptamer strand. The presence of TOB caused the ternary aptamer hybrid to break apart by creating the complex between the aptamer and TOB, separating the aptamer strands from the LC-aqueous interface. Subsequently, the TOB presence was specified by inducing a color change in the polarized vision of the aptasensor platform, resulting in a shift from colorful to murky. The aptasensor could monitor TOB in the linear concentration range of 1 fM-10 nM, with an impressively low detection limit of 0.217 fM. With the capability to determine TOB in beef, chicken egg, and low-fat milk, the LC-decorated aptasensor is proficient in food quality control. The aptasensor possesses characteristics such as simplicity, high sensitivity, ease of use, and affordability. As a result, it has the potential to be marketed as a portable testing kit that is convenient and cost-effective.