Deep Plasma Proteome Profiling by Modulating Single Nanoparticle Protein Corona with Small Molecules.

The protein corona, a dynamic biomolecular layer that forms on nanoparticle (NP) surfaces upon exposure to biological fluids is emerging as a valuable diagnostic tool for improving plasma proteome coverage analyzed by liquid chromatography-mass spectrometry (LC-MS/MS). Here, we show that spiking small molecules, including metabolites, lipids, vitamins, and nutrients, into plasma can induce diverse protein corona patterns on otherwise identical NPs, significantly enhancing the depth of plasma proteome profiling. The protein coronas on polystyrene NPs when exposed to plasma treated with an array of small molecules (n=10) allowed for detection of 1793 proteins marking an 8.25-fold increase in the number of quantified proteins compared to plasma alone (218 proteins) and a 2.63-fold increase relative to the untreated protein corona (681 proteins). Furthermore, we discovered that adding 1000 µg/ml phosphatidylcholine could singularly increase the number of unique proteins within the protein corona (897 proteins). This specific concentration of phosphatidylcholine selectively depleted the four most abundant plasma proteins, including albumin, thus reducing concentration dynamic range of plasma proteome and boosting LC-MS/MS sensitivity for detection of proteins with lower abundance. By employing an optimized data-independent acquisition (DIA) approach, the inclusion of phosphatidylcholine led to the detection of 1436 proteins in plasma. This significant achievement is made utilizing only a single NP type and one small molecule to analyze a single plasma sample, setting a new standard in proteomic depth of the plasma sample. Given the critical role of plasma proteomics in biomarker discovery and disease monitoring, we anticipate widespread adoption of this methodology for identification and clinical translation of proteomic biomarkers into FDA approved diagnostics.

Protein Corona Composition of Gold Nanocatalysts.

The interaction between nanoparticles (NPs) and biological environments is profoundly influenced by a stable, strongly adsorbed "hard" protein corona. This corona significantly determines the NPs' pharmacokinetics and biological destiny. Our study delves into the mechanisms by which colloidal Au nanocrystals that are synthesized electrochemically without surface-capping organic ligands, known as CNM-Au8, traverse the blood-brain barrier (BBB) and target human brain tissue for treating neurodegenerative disorders. We discovered that upon interaction with human plasma, CNM-Au8 gold nanocrystals (AuNCs) effectively attract a variety of crucial apolipoproteins, notably apolipoproteins E, to their surfaces. This interaction likely facilitates their passage through the BBB. Furthermore, the coronas of these AuNCs exhibit a substantial presence of albumin and a notable absence of opsonin-based proteins, contributing to prolonged blood circulation. These characteristics align well with the clinical performance observed for the CNM-Au8 NCs. This study highlights that AuNCs with intentionally engineered structures and surfactant-free surfaces can create a distinct protein corona composition. This finding holds significant promise for the development of advanced therapeutic agents aimed at combating neurodegenerative diseases.