Detection of plasmonic circular dichroism on biotemplated gold

The achievement of strong chiroptical activity has the potential to revolutionize the field of plasmonics and will pave the way for innovative applications in sensing, molecular recognition, and nanophotonic device engineering. The self-ordering of achiral nanoparticles into optically active biotemplates offers a versatile route to control the structure and optical activity in the visible region. Biotemplates with cholesteric ordering offers an excellent platform to achieve such circular dichroism in plasmonics. This work focuses on the production of biotemplates sourced from king prawn shells exoskeleton and selforganization of gold nanoparticles that are produced in-situ. Our work addresses the challenges stemming from bio-sourced temples such as structural imperfections that affect measuring the chiroptical activity by developing custom-designed and in-house built frames and holders that are compatible with commercial circular dichroism spectrometers. Such solid-state frames facilitate measurement accuracy and reproducibility. Upon loading of the AuNPs to membranes via in situ cyclic reduction, we recorded a change in the CD spectra of the Au-loaded membranes near the plasmonic resonances of gold indicating a coupling to the helicoidal pitch of the biotemplates.