Cellular uptake of ribonuclease A-functionalised core-shell silica microspheres

G.F Chimonides, J.M. Behrendt, E. Chundoo, C. Bland, A.V. Hine, A. Devitt, D.A. Nagel, A.J. Sutherland*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Analysis of protein function in a cellular context ideally requires physiologically representative levels of that protein. Thus conventional nucleic acid-based transfection methods are far from ideal owing to the over expression that generally results. Likewise fusions with protein transduction domains can be problematic whilst delivery via liposomes/nanoparticles typically results in endosomal localisation. Recently polymer microspheres have been reported to be highly effective at delivering proteins into cells and thus provide a viable new alternative for protein delivery (protein transduction). Herein we describe the successful delivery of active ribonuclease A into HeLa cells via novel polymer core-silica shell microspheres. Specifically, poly(styrene-co-vinylbenzylisothiouronium chloride) core particles, generated by dispersion polymerisation, were coated with a poly(styrene-co-trimethoxysilylpropyl methacrylate) shell. The resultant core-shell morphology was characterised by transmission electron, scanning electron and fluorescence confocal microscopies, whilst size and surface charge was assessed by dynamic light scattering and zeta-potential measurements, respectively. Subsequently ribonuclease A was coupled to the microspheres using simple carbodiimide chemistry. Gel electrophoresis confirmed and quantified the activity of the immobilised enzyme against purified HeLa RNA. Finally, the polymer-protein particles were evaluated as protein-transduction vectors in vitro to deliver active ribonuclease A to HeLa cells. Cellular uptake of the microspheres was successful and resulted in reduced levels of both intracellular RNA and cell viability.
Original languageEnglish
Pages (from-to)7307-7315
Number of pages9
JournalJournal of Materials Chemistry B
Issue number42
Early online date27 Aug 2014
Publication statusPublished - 14 Nov 2014

Bibliographical note

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.

Funding: EPSRC Industrial CASE (GFC) grant number EP/D038057/1
Electronic supplementary information: see DOI: 10.1039/c4tb01130a


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