Formation of Myoglobin Corona at Polymer Microparticles

Zbigniew Adamczyk,Małgorzata Nattich-Rak

doi:10.3390/colloids5020027

Abstract

Adsorption of myoglobin molecules at negatively charged polystyrene microparticles was studied using the dynamic light scattering (DLS), electrophoresis (LDV) and the solution depletion method involving atomic force microscopy (AFM). The measurements were carried out at pH 3.5 and NaCl concentration of 10−2 and 0.15 M. Initially, the stability of myoglobin solutions and the particle suspensions as a function of pH were determined. Afterward, the formation of myoglobin molecule corona was investigated via the direct electrophoretic mobility measurements, which were converted to the zeta potential. The experimental results were quantitatively interpreted in terms of the general electrokinetic model. This approach yielded the myoglobin corona coverage under in situ conditions. The maximum hard corona coverage was determined using the AFM concentration depletion method. It was equal to 0.9 mg m−2 for the NaCl concentration in the range 0.01 to 0.15 M and pH 3.5. The electrokinetic properties of the corona were investigated using the electrophoretic mobility measurements for a broad pH range. The obtained results confirmed that thorough physicochemical characteristics of myoglobin molecules can be acquired using nM amounts of the protein. It was also argued that this method can be used for performing electrokinetic characteristics of other proteins such as the SARS-Cov-2 spike protein exhibiting, analogously to myoglobin, a positive charge at acidic pHs.

Highlights

The formation of protein coronas at nanoparticles was extensively studied, both for single molecule systems and for mixtures comprising the blood serum [1,2,3,4,5,6]
Experimental results acquired for albumins [7], immunoglobulin [8] and lysozyme [9] using polymer microparticles confirm that these systems are prone to a theoretical interpretation
Given the deficit of reliable information, the goal of this work is to determine the mechanism of myoglobin adsorption at polymer microparticles with the emphasis focused on the hard corona formation

Summary

Introduction

The formation of protein coronas at nanoparticles was extensively studied, both for single molecule systems and for mixtures comprising the blood serum [1,2,3,4,5,6]. Because of relatively low stability, soft corona composition and structure are difficult to be determined by available experimental techniques, which require nanoparticle suspension centrifugation or filtration steps. Another disadvantage consists in the destabilization of the suspension by the soft coronas, which may promote bringing interactions among nanoparticles. One can argue that more reliable results prone to a quantitative interpretation can be acquired if the formation of soft corona is prohibited. Experimental results acquired for albumins [7], immunoglobulin [8] and lysozyme [9] using polymer microparticles confirm that these systems are prone to a theoretical interpretation

Objectives

Methods

Results

Conclusion