TY - JOUR

T1 - Dynamic Surface Properties of Mixed Dispersions of Silica Nanoparticles and Lysozyme

AU - Milyaeva, Olga Yu.

AU - Campbell, Richard A.

AU - Gochev, Georgi

AU - Loglio, Giuseppe

AU - Lin, Shi Yow

AU - Miller, Reinhard

AU - Noskov, Boris A.

PY - 2019/6

Y1 - 2019/6

N2 - The surface properties of mixed aqueous dispersions of lysozyme and silica nanoparticles were studied using surface-sensitive techniques in order to gain insight into the mechanism of the simultaneous adsorption of protein/nanoparticle complexes and free protein as well as the resulting layer morphologies. The properties were first monitored in situ during adsorption at the air/water interface using dilatational surface rheology, ellipsometry, and Brewster angle microscopy. Two main steps in the evolution of the surface properties were identified. First, the adsorption of complexes did not lead to significant deviations in the dynamic surface elasticity and dynamic surface pressure from those for a layer of adsorbed lysozyme globules. Second, through the gradual displacement of protein globules from the interfacial layer as a result of further complex adsorption, the layer became more dense with much higher dynamic surface elasticity (∼280 mN/m compared to ∼80 mN/m for a pure protein layer). These layers were shown to be fragile and could be easily broken into separate islands of irregular shape by a weak mechanical disturbance. The layer properties were then monitored following their transfer to solid substrates using atomic force microscopy and scanning electron microscopy. These layers were shown to consist of nanoparticles surrounded by a rough shell of protein globules, whereas some particles tended to form filamentous aggregates. This comprehensive study provides new mechanistic and morphological insight into the surface properties of a model protein/nanoparticle system, which is of fundamental interest in colloidal science and can be extended to systems of physiological relevance.

AB - The surface properties of mixed aqueous dispersions of lysozyme and silica nanoparticles were studied using surface-sensitive techniques in order to gain insight into the mechanism of the simultaneous adsorption of protein/nanoparticle complexes and free protein as well as the resulting layer morphologies. The properties were first monitored in situ during adsorption at the air/water interface using dilatational surface rheology, ellipsometry, and Brewster angle microscopy. Two main steps in the evolution of the surface properties were identified. First, the adsorption of complexes did not lead to significant deviations in the dynamic surface elasticity and dynamic surface pressure from those for a layer of adsorbed lysozyme globules. Second, through the gradual displacement of protein globules from the interfacial layer as a result of further complex adsorption, the layer became more dense with much higher dynamic surface elasticity (∼280 mN/m compared to ∼80 mN/m for a pure protein layer). These layers were shown to be fragile and could be easily broken into separate islands of irregular shape by a weak mechanical disturbance. The layer properties were then monitored following their transfer to solid substrates using atomic force microscopy and scanning electron microscopy. These layers were shown to consist of nanoparticles surrounded by a rough shell of protein globules, whereas some particles tended to form filamentous aggregates. This comprehensive study provides new mechanistic and morphological insight into the surface properties of a model protein/nanoparticle system, which is of fundamental interest in colloidal science and can be extended to systems of physiological relevance.

KW - HUMAN SERUM-ALBUMIN

KW - INTERACTIONS OPPORTUNITIES

KW - CONFORMATIONAL-CHANGES

KW - PROTEIN ADSORPTION

KW - CORONA

KW - ORIENTATION

KW - INTERFACE

KW - SIZE

KW - TRANSITIONS

KW - PARTICLES

UR - http://www.scopus.com/inward/record.url?scp=85066915679&partnerID=8YFLogxK

U2 - 10.1021/acs.jpcb.9b03352

DO - 10.1021/acs.jpcb.9b03352

M3 - Article

C2 - 31082226

AN - SCOPUS:85066915679

VL - 123

SP - 4803

EP - 4812

JO - Journal of Physical Chemistry B

JF - Journal of Physical Chemistry B

SN - 1520-6106

IS - 22

ER -