Images

On-demand delivery of single DNA molecules

lightswitch

Nanopipettes can be used to analyse and deliver DNA molecules one at the time with the flip of a switch. By using voltage pulses we could control the time of ejection of the first DNA molecule and the number of molecules delivered. Beside begin a very neat effect, demonstrated both experimentally and from simulations, we believe this technology could be used to deliver individual DNA plasmids inside single cells to study DNA transfection.

Prussian blue Nanoelectrode

prussian

Carbon nanoelectrodes fabricated using the procedure described here can be electrochemically etched to from a nanocavity. We deposited Prussian Blue, one of the first modern pigment and an excellent catalyst for the reduction of hydrogen peroxyde, within formed nanocavity. This allowed the quantification of H2O2 within 10 μM – 3 mM. We envision the application of these nanosensors for the intracellular monitoring of oxidative stress in living cells.

Carbohydrate-activated nanofluidic diode

sweetsHD

We developed a nanopipette that can detect sugars in solution. We achieved this by functionalizing the nanopipette opening with a polyelectrolyte bearing boronic acid moieties.  The functionalized nanopipette acts as a fluidic diode where the rectification of the ionic current flowing through the nanopipette depends on the concentraiton of sugars in solution.

Nano-injection system for single-cell surgery

cellinjection

Manipulation and analysis of single cells is the next frontier in understanding processes that control the function and fate of cells. We devised a system that uses scanning ion conductance microscopy (SICM) to detect cell surfaces, and voltage pulses to deliver molecules into living cells in culture.

Using double barrel nanopipettes we could independently deliver two different molecules. As a proof of concept, we injected adherent mammalian cells with fluorescent dyes but we are investigating the delivery of biologically relevant molecules (like DNA and proteins).