Nanophotonic tools based on the conjugates of nanoparticles with the single-domain antibodies for multi-photon micrometastases detection and ultrasensitive biochemical assays

Abstract

Semiconductor quantum dots (QDs) are characterized by orders of magnitude higher multiphoton linear absorption cross-sections compared with conventional organic dyes. Combined with the QD photoluminescence quantum yield approaching 100%, this fact opens great prospects for the twophoton functional tumor imaging with QDs tagged with highly specific recognition molecules. Single-domain antibodies (sdAbs) or “nanobodies” derived from lamas are the smallest high-affinity recognition molecules, which may be tagged with the QDs thus permitting not only solid tumors multiphoton imaging but also rare disseminated cancer cells and micrometastases in the depth of the tissue to be detected. Additionally, unique photostability of QDs enables signal accumulation and significant enhancement of the sensitivity of routine biochemical and immunohistochemical assays to be obtained when the conjugates of QDs, instead of organic dyes, are used.