Protein Adsorption and Reorganization on Nanoparticles Probed by the Coffee-Ring Effect: Application to Single Point Mutation Detection

Abstract

The coffee-ring effect denotes the accumulation of particles at the edge of an evaporating sessile drop pinned on a substrate. Because it can be detected by simple visual inspection, this ubiquitous phenomenon can be envisioned as a robust and cost-effective diagnostic tool. Toward this direction, here we systematically analyze the deposit morphology of drying drops containing polystyrene particles of different surface properties with various proteins (bovine serum albumin (BSA) and different forms of hemoglobin). We show that deposit patterns reveal information on both the adsorption of proteins onto particles and their reorganization following adsorption. By combining pattern analysis with adsorption isotherm and zeta potential measurements, we show that the suppression of the coffee-ring effect and the formation of a disk-shaped pattern is primarily associated with particle neutralization by protein adsorption. However, our findings also suggest that protein reorganization following adsorption can dramatically invert this tendency. Exposure of hydrophobic (respectively charged) residues can lead to disk (respectively ring) deposit morphologies independently of the global particle charge. Surface tension measurements and microscopic observations of the evaporating drops show that the determinant factor of the deposit morphology is the accumulation of particles at the liquid/gas interface during evaporation. This general behavior opens the possibility to probe protein adsorption and reorganization on particles by the analysis of the deposit patterns, the formation of a disk being the robust signature of particles rendered hydrophobic by protein adsorption. We show that this method is sensitive enough to detect a single point mutation in a protein, as demonstrated here by the distinct patterns formed by human native hemoglobin h-HbA and its mutant form h-HbS, which is responsible for sickle cell anemia.

Hydrophobic Interaction: A Promising Driving Force for the Biomedical Applications of Nucleic Acids

“…[153][154][155][156] As nanomaterials have large surface-area-to-volume ratios, [157] the complexation with functional biomolecules, including phospholipids, proteins, and nucleic acids, through surface adsorption has become a practical strategy to construct the biomedical materials. [158][159][160][161] In this section, we focus on discussing the use of hydrophobic interactions to form complexes between inorganic nanomaterials and NAs.…”

Self-Assembly of Nanoparticles from Evaporating Sessile Droplets: Fresh Look into the Role of Particle/Substrate Interaction

“…This aspect which has been little studied 1,9-15 so far might become important with the emergence of (i) plasmonic applications requiring deposits with nanoscale resolution 16,17 and no structural defects, such as cracks; and (ii) biomedical applications linking diagnosis to the shape of a deposit obtained by drying a sample of biofluid. [18][19][20][21] The dynamic of particles self-assembly at the contact line during evaporation was studied at the local scale by Yan et al 22 . They showed that attractive DLVO interaction between polystyrene microparticles (~ 800 nm in size) and a negatively charged glass substrate leads to a low mobility of the particles in the vicinity of the substrate resulting in disordered local packing, regardless of the overall shape of the final deposit.…”

Inkjet Printing of Magnetic Particles Toward Anisotropic Magnetic Properties

“…The CRE phenomenon has been the subject of broad investigations and scrutiny to unveil the underlying mechanisms 14,15 . Under certain conditions, when a particle-laden droplet is left to dry on a nonporous substrate, the colloidal particles transport to the three-phase contact line (TCL) resulting in a ring-like particle deposition 16,17 . Two decades ago, Deegan et al .…”