Nanoprobes based on fluorescent semiconductor nanocrystals and single-domain antibodies for highly sensitive detection of epidermal growth factor receptor in tumor cells

Background. The development of highly oriented conjugates of quantum dots (QDs) and single-domain antibodies (sdAbs) as innovative fluorescence imaging nanoprobes that specifically recognize tumor biomarkers, in particular, epidermal growth factor receptor (EGFR), is a promising approach to improving immunohistochemical tumor typing.

Aim. The study was aimed at developing fluorescent nanoprobes based on QDs and sdAbs that specifically recognize EGFR, as well as evaluating their functional characteristics (size and optical properties) and functional activity.

Materials and methods. QDs were obtained using high-temperature organometallic synthesis and transferred into the aqueous phase by means of stepwise replacement of ligands on the QD surface. The QDs and sdAbs were conjugated in an oriented manner using a bifunctional cross-linking agent. Detailed characteristics of the resulting conjugates were analyzed by the dynamic light scattering and immunoassay methods. Functional activity was assessed on the model human epidermoid carcinoma cells line A431.

Results. The QD–sdAb conjugates have been standardized in terms of control parameters determining their functional activity, in particular, hydrodynamic diameter and efficiency of binding with target tumor cells. They are characterized by high dispersity, homogeneity, and specific functional activity towards their molecular target.

Conclusion. The results demonstrate the potential use of the designed QD–sdAb conjugates for EGRF detection in immunohistochemical typing of tumor.

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