Research Interests

Biosensors, Facilitated Diffusion in Membranes, Restricted Diffusion in Membranes, Transport Processes in Tissues, Pharmacokinetics, Immobilized Enzymes, Bioimaging.

Optical Semi-noninvasive Glucose Sensor

Schematics illustrating the principles of the fluorescence affinity hollow fiber sensor. In the absence of glucose, fluorochromelabeled Concanavalin A is bound to fixed glucose residues inside porous beads (left hand). The beads are colored with dyes that prevent the excitation light from penetrating into them and inducing Con A to fluoresce, thus keeping the fluorescence emission at 520 nm. After diffusion of glucose through the hollow fiber membrane (molecular weight cutoff, 10 kDa), Con A is displaced from the beads and diffuses out of them, and hereby fluorochrome-labeled Con A becomes exposed to excitation light resulting in a strong increase in fluorescence (right hand).

Design of a GIP (glucose indicator protein) for sensing glucose based on FRET. (a) Diagram of the GIP structure showing how FRET between two GFPs can measure glucose concentration. The GBP adopts an “open” form in the presence of the glucose, which triggers a conformation change, causing two GFPs apart from the center of GBP leading to the change in FRET. The (b) represents one molecule of the glucose bound onto the binding cleft of the GBP.

Transmission Plasmon Sensor for Biomolecules

(a) SEM image of nanoholes in an optically thin Au film. The holes are 60 nm in diameter, and the Au film is 20 nm thick. (b) Transmission extinction spectra of Au nanoholes on a glass slide. The spectra were taken after the surfaces of Au and glass were (i) cleaned in a mixture of ammonia and hydrogen peroxide, (ii) modified with SAM coatings of DT and OTS, and (iii) further modified by BSA adsorption. The resonance peak shifted about 1.5 and 7 nm to the right after steps (ii) and (iii), respectively.

Hindered Diffusion in Nanoporous Membrane

Pharmacokinetics of Peritoneal Transport

Biomaterials Testing

Annular flow device for determination of the effect of shear on thrombus formation on different materials.

Separation of Gases by Facilitated Diffusion in Liquid Membranes