Possibilities and Limitations of Different Separation Techniques for the Analysis of the Protein Corona

Abstract

One of the biggest challenges in the field of nanomedicine is the adsorption of biomolecules on the nanomaterial upon contact with a biological medium. The interactions of the resulting protein corona are essential for their behavior in a biological system. Thus, it is now commonly accepted that understanding the formation and consequently understanding the influence of the protein corona on the biological response is crucial. However, the outcome of the protein corona characterization cannot easily be compared between different studies and techniques, since many different sample preparation procedures exist that are suitable for different materials or methods. Depending on the applied procedure, the nanomaterial–protein system will be altered in a certain way, so that it is necessary to consider the individual influence on the protein corona. Accordingly, the aim of this Minireview is to give an overview of the applied sample preparation methods for the analysis of the protein corona and to evaluate their influence on the outcome of the results especially with regard to the introduced terms “soft” and “hard protein corona”. Special focus will be placed on the comparison of the most commonly used techniques such as centrifugation, magnetic, and chromatographic separation.

From Protein Corona to Colloidal Self-Assembly: The Importance of Protein Size in Protein–Nanoparticle Interactions

“…This can lead to limitations related to weakly bound proteins or NPs and proteins having similar sedimentation coefficients. 16,66,67 The second technique measures the change in heat in a solution during titration.…”

Polymeric Nanoparticles with Neglectable Protein Corona

“…In contrast to conventional size exclusion chromatography, in AF4 the contact to the interface and the shear forces are substantially reduced, which leads to very mild separation conditions, minimizing perturbations of a potential protein corona. [ 26,31 ] Based on this method, Landfester and coworkers recently fully characterized the protein corona of Lutensol AT50‐coated polystyrene nanoparticles and PEG functionalized liposomes, identifying all adsorbed proteins. [ 19,26 ]…”

Engineered Polymeric Materials for Biological Applications: Overcoming Challenges of the Bio–Nano Interface

“…The formation and dynamic exchange within this coating of adsorbed biological molecules remains ambiguous; however, is believed to possess a specific two-layer morphology [12]. The resulting biomolecular-corona is commonly divided into two layers, the hard and soft corona, referring to the inner and outer proteinaceous shells, respectively [13,14]. The binding proteins and biomacromolecules, broadly denoted as opsonins, modulate the behavior of the potential nanomedicine in vivo, as they are able to signal to the immune system [15], dictate clearance pathways [12], and alter downstream events required for efficacious therapeutic delivery [16].…”

“…While the interaction with blood proteins has been profiled for certain kinds of materials (e.g., gold nanoparticles [29] and liposomes [30]), proteomic fingerprinting has not been done for polymeric nanomedicines (at least under conditions that match those present within the blood stream of an animal). This is due to difficulty in extracting intact complexes and the fragility of the soft corona [14]. A further confounding issue with studying the recruitment and influence of opsonins on materials is the enormous degree of inter-patient variability in the protein content of the plasma [31].…”