Structure and characterisation of hydroxyethylcellulose-silica nanoparticles

• Published in: RSC advances Vol. 8; no. 12; pp. 6471 - 6478
• Main Authors: Mansfield, Edward D H, Pandya, Yash, Mun, Ellina A, Rogers, Sarah E, Abutbul-Ionita, Inbal, Danino, Dganit, Williams, Adrian C, Khutoryanskiy, Vitaliy V
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 01-01-2018; The Royal Society of Chemistry
• Subjects: Aggregates; Chemical synthesis; Chemistry; Condensation polymerization; Drug delivery systems; Fourier transforms; Hydroxyethyl celluloses; Infrared spectroscopy; Macromolecules; Nanoparticles; Neutron scattering; Neutrons; Photon correlation spectroscopy; Polymer coatings; Silicon dioxide; Spectroscopic analysis; Spectrum analysis; Surface properties; Surface stability; Thermogravimetric analysis; Transmission electron microscopy
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c7ra08716k

Functionalising nanoparticles with polymers has gained much interest in recent years, as it aids colloidal stability and manipulation of surface properties. Here, polymer-coated thiolated silica nanoparticles were synthesised by self-condensation of 3-mercaptopropyltrimethoxysilane in the presence of hydroxyethylcellulose. These nanoparticles were characterised by dynamic light scattering, small angle neutron scattering, Nanoparticle Tracking Analysis, Raman spectroscopy, FT-IR spectroscopy, thermogravimetric analysis, Ellman's assay, transmission electron microscopy and cryo-transmission electron microscopy. It was found that increasing the amount of hydroxyethylcellulose in the reaction mixture increased the nanoparticle size and reduced the number of thiol groups on their surface. Additionally, by utilising small angle neutron scattering and dynamic light scattering, it was demonstrated that higher concentrations of polymer in the reaction mixture (0.5-2% w/v) resulted in the formation of aggregates, whereby several silica nanoparticles are bridged together with macromolecules of hydroxyethylcellulose. A correlation was identified between the aggregate size and number of particles per aggregate based on size discrepancies observed between DLS and SANS measurements. This information makes it possible to control the size of aggregates during a simple one-pot synthesis; a prospect highly desirable in the design of potential drug delivery systems.