(a) TEM image of 10 nm diameter magnetic nanoparticles (MNPs). (b) Cryo-SEM image of an MNPV embedded in a hydrogel. (c) Fluorescence microscopy image of dividing myoblasts (green) surrounded by MNPVs (red).

The interface between nanotechnology and biological chemistry promises to be an exciting area for future research. Research in the area exploits the special properties of nanoscale objects; one example is the onset of superparamagnetism in nanoscale magnetite particles.

We have developed magnetic nanoparticle-vesicle assemblies (MNPVs) for the magnetically triggered delivery of biochemicals to cells. MNPVs consist of 800 nm vesicles containing stored (bio)chemicals that are crosslinked by 10 nm superparamagnetic magnetic nanoparticles. We use chemical modification of the surface of nanoparticles and vesicles to “glue” these components together, adding the unique magnetic properties of nanoparticles to membranes of the vesicles. In particular the nanoparticles fulfil two critical roles: (a) they allow magnetic separation of MNPVs and objects linked to them; (b) they allow non-destructive release of the vesicle contents by a 400 kHz alternating magnetic field (AMF).

Porphyrin and saccharide-coated magnetic nanoparticles adhering to 3T3 fibroblast cells.

We have used hydrogel extravesicular matrixes to fix patterns of magnetically labeled vesicles into place and create new "smart" biomaterials. The self-supporting hydrogel matrix surrounds and strengthens the vesicle assemblies, giving materials that act as bionanotechnological interfaces for converting electromagnetic signals into chemical messengers. We have shown cells to be unaffected by MNPVs storing bioactive compounds. However subsequent application of an AMF released the stored compounds, which then induced a cellular response.

We have also been developing new oligosaccharide coating agents to target superparamagnetic nanoparticles to selected cell types, which may permit both the diagnosis (through MRI) and the treatment (through hyperthermia) of diseased regions of the body ("theranostic" particles).

A versatile approach towards multivalent saccharide displays on magnetic nanoparticles and phospholipid vesicles.

Coxon, T. P.; Fallows, T. W.; Gough J. E.; Webb, S.J.

Org. Biomol. Chem. 2015, 13 10751–10761.

Invited submission for “Multivalent Biomolecular Recognition” web-themed issue.

Free to view (Open Access)

Magnetically-Controlled Release from Hydrogel-Supported Vesicle Assemblies.

Mart, RJ; Liem, KP; Webb, SJ.

Chem. Commun. 2009, 2287-2289.

Selected as a “hot” article (http://www.rsc.org/chemcomm/hot), highlighted in Chem. Technol. 2009, 6, T36 and in Chemistry World, 2009, 6, 30.

Magnetic assembly and patterning of vesicle/nanoparticle aggregates.

Liem, KP; Mart, RJ; Webb, SJ.

J. Am. Chem. Soc. 2007, 129, 12080-12081.