March Newsletter: Page 2
Professor Dan Goia
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As part of the same project, Dr. Goia’s group has also perfected a process that allows selective removal of the base metal core and the formation of hollow NiPt alloy nanoparticles with open structures (Figure 2). As in the case of ‘solid core’ particles, the gradient of Pt concentration in the shell can be varied from its center to periphery and the Ni:Pt ratio of the surface controlled. The substantially increased specific surface due to interior cavities and the low curvature of both internal and external surfaces provide an additional increase in the mass specific activity. To date, the results of the research related to these unique catalyst architectures have been captured in five worldwide patents.
Figure 2: Hollow NiPt alloy particles (left); high resolution TEM image of a hollow NiPt naonoparticle (right).
Biomolecular Release Triggered by Glucose Input – Bioelectronic Coupling of Sensing and Actuating Systems
Professor Evgeny Katz and a group of postdocs and students designed a new “smart” drug-delivering system. A drug-mimicking release process was triggered by a glucose signal. The presence of glucose resulted in the formation of a negative potential on an electrode modified with PQQ-dependent glucose dehydrogenase. The glucose oxidizing enzyme electrode was coupled with another electrode coated with Fe+3-crosslinked alginate polymer film.
Graduate student Shay Mailloux
Formation of negative potential in the presence of glucose resulted in the reduction of crosslinking Fe+3 cations and dissolution of the alginate film. The entrapped species were released from the dissolved alginate mimicking signal-controlled drug release. In order to minimize non-controlled leakage from the alginate, large species, horseradish peroxidase–Au nanoparticle conjugates, were entrapped into and then released from the alginate polymer. The electronic coupling between glucose sensing and releasing systems allows a simple platform for future drug releasing systems triggered by biochemical signals. See Figure 3. The research is mostly performed by Shay Mailloux – a Ph.D. student in Professor Katz’s research group.
Figure 3: Illustration of the drug-releasing process.