Sub-100 nm thiolated silica nanoparticles were synthesized by self-condensation of (3-marcaptopropyl)trimethoxysilane (MPTS) in dimethylsulfoxide [1]. These nanoparticles offered an excellent platform for further functionalization such as fluorescent labelling and covalent attachment of hydrophilic polymers (polyethyleneglycol, poly(N-isopropylacrylamide) and poly(2-ethyl-2-oxazoline)) [2]. The thiolated and functionalized nanoparticles were characterized using a range of physicochemical methods including dynamic light scattering, nanoparticle tracking analysis, small angle neutron scattering and transmission electron microscopy. The thiolated nanoparticles were found to exhibit excellent adhesion to biological surfaces such as ocular and urinary bladder mucosa, which makes them promising for development as drug delivery systems. They also were found to be an excellent model to probe the barrier function of ocular membranes. The diffusion of fluorescently labelled thiolated and PEGylated nanoparticles in solutions of different water-soluble polymers was studied using nanoparticle tracking analysis (NanoSight Ltd) [3]. It was established that the diffusivity of nanoparticles is not only affected by their dimensions and solution viscosity, but also by the specific interactions with the components of the liquid media. The nanoparticles functionalized with polymers were found to exhibit enhanced diffusion in biological media such as mucus gels.
References:
[1] G.S. Irmukhametova G.S., G.A. Mun, V.V. Khutoryanskiy, Langmuir 2011, 27, 9551.
[2] G.S. Irmukhametova, B. Fraser, J.L. Keddie, G.A. Mun, V.V. Khutoryanskiy, Langmuir 2012, 28, 299.
[3] E.A. Mun, C. Hannell, S.E. Rogers, P. Hole, A.C. Williams, V.V. Khutoryanskiy, Langmuir 2014, 30, 308.
v.khutoryanskiy@reading.ac.uk
