Detection of Molecules Based on Enhanced Backscattering Effect in Microsphere Lens

Owning to the enhanced backscattering effect in the photonic nanojet, detection approach based on measuring the backscattering signal allows for the detection of micro- and nanoscale objects with single-object resolution. However, this approach fails in the detection of molecules, since the weak light-matter interaction between photonic nanojet and molecules is always insufficient to excite detectable backscattering signal. To address this issue, we employ signal amplification via ternary assembly of lens-aptamer-nanoparticle complex to enhance the backscattering signal triggered by molecules. We show that this approach reveals pronounced enhancement on backscattering signals and therefore allows successive detection of molecules in the solution. This approach provides a step forward in facilitating photonic nanojet towards practical application in the field of highly sensitive detection of bio/chemical molecules.