Implications of nanoparticle-protein interactions on protein assembly and conformation

Unnikrishnan, Mahima

Permalink

https://hdl.handle.net/2142/125796 Copy

Description

Title

Implications of nanoparticle-protein interactions on protein assembly and conformation

Author(s)

Unnikrishnan, Mahima

Issue Date

2024-07-10

Director of Research (if dissertation) or Advisor (if thesis)

• Murphy, Catherine J
• Gruebele, Martin

Doctoral Committee Chair(s)

• Murphy, Catherine J
• Gruebele, Martin

Committee Member(s)

• Jain, Prashant K
• Selvin, Paul R

Department of Study

Chemistry

Discipline

Chemistry

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Protein corona
• Colloidal inorganic nanoparticles
• Nano-bio interface
• Nanomaterial-protein interactions

Abstract

The interaction between nanoparticles and proteins presents a promising avenue for designing nanoparticulate theranostic and diagnostic agents in the biomedical field. Upon entering the body, it is not the as-synthesized nanoparticles, but biomolecule-coated nanoparticles that dictate their function and therapeutic response. By regulating the composition of protein corona on the particles, it becomes possible to conceal the nanoparticle surface and facilitate specific biological functions. Although some fundamental principles guiding interactions between nanoparticles and proteins have been established and accepted by the scientific community, there is ongoing debate regarding the development of a universally applicable theoretical framework for understanding the protein corona due to missing pieces in the puzzle. The work presented in this thesis aims to expand the current understanding of how nanoparticles can alter protein self-assembly and conformation using colloidal inorganic nanoparticles as a platform for corona formation. Chapter 1 covers how nanomaterials came to be popular in the biomedical field and why studying the molecular mechanisms underlying nanoparticle-protein interactions can significantly contribute to successful translation of in vitro findings to in vivo settings. Dynamic nature of the protein corona and the many analytical techniques used for its characterization are discussed. An overview of changes in protein conformation and activity upon adsorption to a nanoparticle surface, its correlation to various biophysicochemical properties governing the nano-bio interface, and the current research challenges associated with the field are also discussed. Chapter 2 presents a systematic investigation of the effect of unfunctionalized silica nanoparticles on the self-assembly of a bacterial tubulin protein pair in buffer, in cell lysate, and in a living mammalian cell using Förster resonance energy transfer. The common assumption that nanoparticle-biomolecular interactions that are studied intensively in vitro are good predictors of in vivo activity are shown to be invalid in the case of protein assembly of bacterial tubulins. In buffer, silica nanoparticles promote the complex formation of tubulin proteins as a function of nanoparticle concentration. However, upon microinjection of these tubulins into live cells, nanoparticles at similar concentration have no effect on protein assembly, confirming the environment-dependence of corona formation. In chapter 3, conformational changes in soft corona proteins incubated with gold nanoparticles in buffer are explored; the overarching research problem addressed being ‘can transient interactions with nanoparticles induce permanent protein denaturation?’. In the first part of the chapter, interaction of cationic polymer-wrapped nanoparticles with superoxide dismutase is discussed, while the latter portion of the chapter describes studies performed with chymotrypsin and serum albumin proteins exposed to anionic nanoparticles. Interferences in data due to protein interaction with the free ligand as well as the solid-liquid or air-liquid interfaces during the incubation step, and not weak protein-nanoparticle interactions, were identified as the key factors contributing to results from these studies.

Graduation Semester

2024-08

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/125796

Copyright and License Information

Copyright 2024 Mahima Unnikrishnan

Owning Collections