(a) TEM image of 10 nm diameter magnetic nanoparticles (MNPs). (b) Cryo-SEM image of an MNPV embedded in an alginate hydrogel. (c) Fluorescence microscopy image of dividing myoblasts (green) surrounded by MNPVs (red fluorescence).
The interface between nanotechnology and biological chemistry promises to be an exciting area for future research. 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).
Our latest work in this area focuses on the use of hydrogel extravesicular matrixes to fix patterns of magnetically labeled vesicles into place and create new "smart" biomaterials. Magnetic nanoparticle-vesicle aggregates in a solution of sodium alginate can be magnetically focused to give patterns, which are set by the infusion of calcium chloride solution.
Iminodiacetate ligands can bind to histidine functionalised magnetite nanoparticles and a magnet can be used to pull red vesicles in a yellow solution to the side of the vial.
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.
Magnetically-Controlled Release from Hydrogel-Supported Vesicle Assemblies.
Chem. Commun. 2009, 2287-2289.
Magnetic assembly and patterning of vesicle/nanoparticle aggregates.
J. Am. Chem. Soc. 2007, 129, 12080-12081.