Protein Corona Composition and Dynamics on Carbon Nanotubes in Blood Plasma and Cerebrospinal Fluid

Abstract

When a nanoparticle enters a biological environment, the surface is rapidly coated with proteins to form a "protein corona". Presence of the protein corona surrounding the nanoparticle has significant implications for applying nanotechnologies within biological systems, affecting outcomes such as biodistribution and toxicity. Herein, we measure protein corona formation on single-stranded DNA wrapped single-walled carbon nanotubes (ssDNA-SWCNTs), a high-aspect ratio nanoparticle ideal for sensing and delivery applications, and polystyrene nanoparticles, a model nanoparticle system. The protein corona of each nanoparticle is studied in human blood plasma and cerebrospinal fluid. We characterize corona composition by proteomic mass spectrometry to determine abundant and differentially enriched vs. depleted corona proteins. Highbinding corona proteins on ssDNA-SWCNTs include proteins involved in lipid binding and transport (clusterin and apolipoprotein A-I), complement activation (complement C3), and blood coagulation (fibrinogen). Of note, albumin is the most common blood protein (55% w/v), yet exhibits low-binding affinity towards ssDNA-SWCNTs, displaying 1300-fold lower bound concentration relative to native plasma. We investigate the role of electrostatic and entropic interactions driving selective protein corona formation, and find that hydrophobic interactions drive inner corona formation, while shielding of electrostatic interactions allows for outer corona formation. Lastly, we study real-time binding of proteins on ssDNA-SWCNTs and find relative agreement between proteins that are enriched and bind strongly, such as fibrinogen, and proteins that are depleted and bind marginally, such as albumin. Interestingly, certain proteins express contrary behavior in single-protein experiments than within the whole biofluid, highlighting the importance of cooperative mechanisms driving selective corona adsorption on the SWCNT surface. Knowledge of the protein corona composition, dynamics, and structure informs translation of engineered nanoparticles from in vitro design to effective in vivo application.

Protein Coronas Derived from Cerebrospinal Fluid Enhance the Interactions Between Nanoparticles and Brain Cells

“…[15] In contrast, it is in agreement with research on serum-and CSF-derived corona formation on non-PEGylated particles and carbon nanotubes, where albumin is over 2.5 million-fold lower as compared to source fluid. [14] Albumin is a notable high abundance-low affinity protein [27] and readily binds to particles within a short time frame, such as the 10 minutes allowed for corona formation on PEG-PNPs in the previous study. [15] This transient corona is then replaced by lower abundance, but higher affinity proteins overtime, [31] as reported in the 1 hour corona formation on carbon nanotubes, [14] and as we report here, where corona formation was allowed to occur over 6 hours.…”

“…In contrast, CSF coronas exhibited a depletion in aromatic residues tryptophan and phenylalanine, which is expected given that these amino acids are instead enriched in coronas on nanoparticles capable of π-π binding interactions, like carbon nanotubes. [14] As depicted in Figure 2e (functional classification of all identified Top-200 proteins: Supplementary Table S2), the major functional classes in native serum and CSF included acute phase proteins (e.g., albumin), immunoglobulins, protease inhibitors and transfer/carrier proteins/transporters. Serum comprised a higher percentage of immunoglobulins (29%) compared to CSF (17%), while CSF had a greater abundance of acute phase proteins (30%) than serum (21%).…”

“…This is consistent with earlier reports, where immunoglobulins were depleted in serum coronas on polystyrene nanoparticles (PNPs) and carbon nanotubes. [14] Additionally, apolipoproteins were the most enriched functional class of proteins, accounting for 3 out of 6 enriched proteins; namely, apolipoprotein A-IV (APOA4) (Log 2 =3; 7 th most abundant), apolipoprotein E (APOE) (Log 2 =2.5; 6 th most abundant), and apolipoprotein A-I (APOA1; Log 2 =2.5; 2 nd most abundant). While APOE and APOA4 have been shown to be enriched in serum coronas on polystyrene nanoparticles, APOA1 was depleted; conversely, on carbon nanotubes AOPE was enriched, while APOA1 and APOA4 were depleted.…”

“…While APOE and APOA4 have been shown to be enriched in serum coronas on polystyrene nanoparticles, APOA1 was depleted; conversely, on carbon nanotubes AOPE was enriched, while APOA1 and APOA4 were depleted. [14] This highlights how nanoparticle characteristics can influence the specific protein enrichment in the protein corona, which may, in turn, have implications for distinct functional and safety profiles between different classes of nanoparticles.…”

Nanoparticle protein corona: from structure and function to therapeutic targeting

“…28 The impact of cooperative interactions between proteins on the evolution of the PC is well documented. 26,107,108 For example, the kinetics of the adsorption process for the hard PC formation is slower than the formation of the soft PC, suggesting the significance of cooperative effects. 108 Stiff and hydrophobic annealed poly-L-lysine (PLL)/sodium alginate (Alg) polyelectrolyte multilayers (PEMs) with a high number of negative moieties lead to a cooperative interaction between BSA and FN in the PC.…”