(51h) Elucidating Protein Corona Composition and Dynamics on Nanoparticles in Biological Environments

Engineered nanoparticles are increasingly used for biological sensing, imaging, and delivery due to their distinctive optical and physical properties. Specifically, DNA functionalized single-walled carbon nanotube (DNA-SWCNT) probes operate at spatiotemporal scales necessary to capture information on chemical signaling, such as neurotransmission in the brain,¹ and can deliver nucleic acid cargo for genetic transformations, such as in living plants.² The critical – and often overlooked – challenge with these nanoscale tools is understanding the fundamental mechanisms of interaction between the nanoprobe and the system they are designed to query. When a nanoparticle enters a biological system, the surface becomes rapidly coated with proteins to form the “protein corona”. Binding of proteins to the nanoparticle disrupts intended functionality and leads to unpredictable in vivo biodistribution and biocompatibility outcomes.

A comprehensive understanding of the protein corona remains a paramount barrier to successfully developing and implementing nanotechnologies within biological environments. Herein, I present multimodal characterization of (i) the protein corona composition on DNA-SWCNTs in blood plasma and cerebrospinal fluid, (ii) the kinetics of protein adsorption to DNA-SWCNTs in solution, and (iii) the colloidal morphology of proteins adsorbed to DNA-SWCNTs. I have optimized a platform to characterize protein corona composition formed on DNA-SWCNTs by proteomic mass spectrometry to determine abundant and differentially enriched vs. depleted corona proteins.³ By varying incubation conditions of DNA-SWCNTs in biofluids, I have investigated the role of electrostatic and entropic interactions driving selective protein corona formation. To study the dynamic exchange of biomolecules on the SWCNT surface, I have developed a multiplexed fluorescence assay that enables real-time tracking of biomolecule adsorption and desorption events.⁴ This corona exchange assay is generic towards the study of various biomolecules exchanging on the SWCNT surface and enables study in solution rather than on a surface-immobilized, less biologically relevant, setting.⁵ Finally, I probe the morphology of DNA-SWCNT complexes in the presence of high- and low-binding model proteins (fibrinogen and albumin, respectively) using in-solution small angle x-ray scattering (SAXS).

Understanding the corona composition, timescales and driving forces of formation, and coronal geometry under relevant solution conditions informs design and synthesis of nanotechnology-based tools applied in protein-rich environments. Although corona formation can impair nanobiotechnology efficacy, it also presents an opportunity to create improved protein-nanoparticle architectures by exploiting selective protein adsorption to the nanoparticle surface. In this work, I develop techniques and analyses that directly characterize the in-situ protein corona microenvironment and employ this knowledge towards rational design of nanobiotechnologies.

References

1. Beyene, A. G., McFarlane, I. R., Pinals, R. L. & Landry, M. P. Stochastic Simulation of Dopamine Neuromodulation for Implementation of Fluorescent Neurochemical Probes in the Striatal Extracellular Space. ACS Chem. Neurosci. 8, 2275–2289 (2017).
2. Demirer, G. S., Zhang, H., Goh, N. S., Pinals, R. L., Chang, R. & Landry, M. P. Carbon Nanocarriers Deliver siRNA to Intact Plant Cells for Efficient Gene Knockdown. bioRxiv 564427 (2019) doi:10.1101/564427.
3. Pinals, R. L. et al. Protein Corona Composition and Dynamics on Carbon Nanotubes in Blood Plasma and Cerebrospinal Fluid. bioRxiv 2020.01.13.905356 (2020) doi:10.1101/2020.01.13.905356.
4. Pinals, R. L., Yang, D., Lui, A., Cao, W. & Landry, M. P. Corona Exchange Dynamics on Carbon Nanotubes by Multiplexed Fluorescence Monitoring. J. Am. Chem. Soc. (2019) doi:10.1021/jacs.9b09617.
5. Alizadehmojarad, A. A., Zhou, X., Beyene, A. G., Chacon, K., Sung, Y., Landry, M. P. & Vuković, L. Binding affinity and conformational preferences influence kinetic stability of short oligonucleotides on carbon nanotubes. bioRxiv 2020.02.08.939918 (2020) doi:10.1101/2020.02.08.939918.