Publications

The properties of nanoparticles (NPs) can change upon contact with serum components, occluding the NP surface by forming a biomolecular corona. It is believed that targeted NPs can lose their functionality due to this biological coating, thus losing specificity and selectivity toward target cells and leading to poor therapeutic efficiency. A better understanding of how the biomolecular corona affects NP ligand functionality is needed to maintain NP targeting capabilities. However, techniques that can quantify the functionality of NPs at a single-particle level in a complex medium are limited and often laborious in sample preparation, measurement, and analysis. In this work, the influence of serum exposure on the functionality of antibody-functionalized NPs was quantified using a straightforward total internal reflection fluorescence (TIRF) microscopy method and evaluated in cell uptake studies. The single-particle resolution of TIRF reveals the interparticle functionality heterogeneity and the substantial differences between NPs conjugated with covalent and noncovalent methods. Notably, only NPs covalently conjugated with a relatively high amount of antibodies maintain their functionality to a certain extent and still showed cell specificity and selectivity toward high receptor density cells after incubation in full serum. The presented study emphasizes the importance of single-particle functional characterization of NPs in complex media, contributing to the understanding and design of targeted NPs that retain their cell specificity and selectivity in biologically relevant conditions.

JTD Keywords: binding, biomolecular corona, cell selectivity, heterogeneity, nanoparticle conjugation, protein corona, tirf microscopy, Active targeting, Biomolecular corona, Cell selectivity, Heterogeneity, Nanoparticle conjugation, Tirf microscopy

© 2020 The Authors Although the concept of selective delivery has been postulated over 100 years ago, no targeted nanomedicine has been clinically approved so far. Nanoparticles modified with targeting ligands to promote the selective delivery of therapeutics towards a specific cell population have been extensively reported. However, the rational design of selective particles is still challenging. One of the main reasons for this is the lack of quantitative theoretical and experimental understanding of the interactions involved in cell targeting. In this review, we discuss new theoretical models and experimental methods that provide a quantitative view of targeting. We show the new advancements in multivalency theory enabling the rational design of super-selective nanoparticles. Furthermore, we present the innovative approaches to obtain key targeting parameters at the single-cell and single molecule level and their role in the design of targeting nanoparticles. We believe that the combination of new theoretical multivalent design and experimental methods to quantify receptors and ligands aids in the rational design and clinical translation of targeted nanomedicines.

JTD Keywords: binding-kinetics, biological identity, biomolecular corona, blood-brain-barrier, drug-delivery, gold nanoparticles, multivalency, nanotechnology, protein corona, quantitative characterization, rational design, super-selectivity, superresolution microscopy, tumor heterogeneity, Ligand-receptor interactions, Multivalency, Nanotechnology, Quantitative characterization, Rational design, Super-selectivity