Self-assembled Star-shaped Chiroplasmonic Gold Nanoparticles for Ultrasensitive Chiro-immunosensor of Viruses

Abstract

Near field optics and optical tunneling light-matter interaction in the superstructure of chiral nanostructures and semiconductor quantum dots exhibit strong optical rotation activity that may open a new window for chiral-based bioanalytes detection. Herein we report an ultrasensitive, chiro-immunosensor using superstructure of chiral gold nanohybrids (CAu NPs) and quantum dots (QDs). Self-assembling techniques were employed to create asymmetric plasmonic chiral nanostructures for extending the spectral range of circular dichroism (CD) response for obtaining superior plasmonic resonant coupling with the QDs excitonic state; this may help to achieve lower the limit of detection (LOD) values. As a result, the designed probe exhibited avian influenza A (H5N1) viral concentration at picomolar level, a significant improvement in sensitivity in comparison to a non-assembled CAu NPs based chiroassay. The practicability of the proposed sensing system was successfully demonstrated on several virus cultures including, avian influenza A (H4N6) virus, fowl adenovirus and coronavirus in blood samples. The results of our study highlights that exciton-plasmon interaction changes chirality and the self-assembled nanostructures are an efficient strategy for enhancing the sensitivity of plasmonic nanosensors.