Multivalent linkers mediated ultra-sensitive bio-detection

In biosensing and diagnostic applications, a key objective is to design detection systems capable of identifying targets at very low concentrations, i.e., achieving high sensitivity. Here, we propose a linker-mediated detection scheme in which the presence of target molecules (linkers) facilitates the adsorption of ligand-coated guest nanoparticles onto a receptor-coated host substrate. Through a combination of computer simulations and mean-field theory, we demonstrate that, at fixed overall binding strength, increasing the valency of linkers exponentially lowers the concentration threshold for detection. This enables the identification of targets at extremely low concentrations, which is critical for early-stage disease and pathogen diagnostics. Furthermore, superselectivity with respect to binding strength is preserved for multivalent linkers, allowing for effective discrimination between targets and non-targets. Our findings highlight multivalency engineering of linkers as a powerful strategy to dramatically enhance the sensitivity of biodetection systems.