An aptamer based wall-less LSPR array chip for label-free and high throughput detection of biomolecules

Despite recent progress in localized surface plasmon resonance (LSPR) based bio-sensing, it remains challenging to achieve sensitive and high throughput LSPR detection with facilities available in common laboratories. Here we developed a wall-less LSPR array chip for facile, label-free and high throughput detection of biomolecules using a normal microplate reader. The wall-less LSPR array chip was fabricated by immobilizing plasmonic nanoparticles (NPs) on a hydrophilic-hydrophobic patterned glass slide, enabling high throughput detection. The wall-less configuration simplifies chip fabrication and sample processing, and enables miniaturization to significantly reduce sample and reagent consumption. A double-gold NPs enhanced system comprising of 13-nm-gold NPs conjugated to aptamer modified 39-nm-gold NPs on glass substrate was adopted to constitute competitive replacement assay for signal amplification in small molecule (i.e. ATP) detection. Upon enhancement, the detection sensitivity of ATP was augmented by 5 orders of magnitude from 0.01 µM to 100 µM measured by the laboratory microplate reader. The wall-less LSPR sensor chip can be widely applied for miniaturized and high throughput detection of a variety of targets in biomedical applications and environmental monitoring using facilities available in common laboratories.