Research Summary

The ability to resolve how different nanoparticle (NP)-properties affects cellular-interactions is critical for understanding nanoconstructs’ design-activity-relationships, which can open important avenues in anti-cancer and immunotherapy research. To achieve such mechanistic understanding, my aim is to test different nanoconstruct designs by visualizing the entire process of NP-cell interaction at single particle level through a semi-continuous and concerted probing. Alongside probing overall impact of a variety of nanoconstructs in cell-cultures, I aim to focus on several different important events in nanoconstruct-cell interaction, starting from probing of NP-cell membrane binding at initial time periods to tracking of NPs inside the live-cells.

The localized surface plasmon resonance (LSPR) of Gold nanoparticle (AuNP) is extremely sensitive towards NP-size-shape-surface chemistry. Differential interference contrast (DIC) imaging done at wavelengths bluer and redder to that of the LSPR, shows an inversion of image-patterns for anisotropic AuNPs. Therefore, the in-situ determination of AuNP structures is possible by carefully choosing suitable imaging-wavelengths, while probing translational and rotational dynamics of nanoconstructs in live-cell by DIC microscopy. Since the type and valency of interaction should control the movement of the NPs in live-cells, hence the ability to probe NP-translation and rotation enable us to understand the nature of their interaction in real-time. I propose to realize a live-cell multi-channel optical microscopy approach for probing both DIC and fluorescence signals during nanoconstruct-cell interaction. The focus will be on several important aspects of NP-properties—such as, NP-surface curvature, size, aspect ratios, surface charge and ligand density etc.—while designing different nanoconstructs suitable for different type of applications and perform a comparative study of their cellular interactions.

The success of a nanoconstruct depends upon several different steps in cell, starting from its plasma-membrane interaction to its subcellular fate. Live-cell DIC imaging provides the ability to follow the entire process on the same set of cells for multiple different types of nanoconstructs and thereby, gives a powerful and versatile platform to generate a strong comparative understanding. The work is aim to bridge a gap in understanding between the overall impact of the nanoconstructs and the details of how their design affects receptor-targeting on plasma-membrane and other important intercellular processes such as endosomal escape.