Nanoenabled Rapid Antigen Test Kits: A Potential Waste Source of Concern with Implications for Environmental Impact

Abstract

Nanoenabled rapid antigen test kits (RATs) are increasingly used for the early detection of various biological markers, including pregnancy testing, ovulation monitoring, drug use screening, HIV diagnostics, and, recently, large-scale screening during the Covid-19 pandemic. Used and unused Covid-19 RATs were studied to estimate the potential generated waste and leaching potential of the nanomaterial in water at pH levels of 4.5 (acidic) and 9 (landfill site). Paper constituted the highest amount of RATs waste (67.70%), followed by plastic (26.96%), while the conjugated test strip accounted for only 0.42%. The primary nanogold (nAu) particle size was 2–16 nm; surface functionalization of the RATs shifted after use, and the concentration of nAu exhibited almost double leaching potential from the conjugated pad after buffer addition (pH 4.5) in used RATs compared to the unused ones. Notably, no significant difference was observed in the leaching of used and unused kits at alkaline pH. These findings strongly suggest that RATs can significantly contribute to nanowaste pollution. Moreover, the interaction of nAu with aqueous solutions at varying pH levels influences the leaching potential and its subsequent fate in the environment. This highlights the urgent need for improved regulation, monitoring, and disposal for these diagnostic kits.