List of Subprojects (the titles are links to the projects)
Development of Microfluidic Devices and New Materials for Novel Applications (Gomez and Scherer)
The Study of Drug Release Using the Self-Assembly of Fluoroalkyl-Ended Poly(ethylene glycol) by NMR Methods of Relaxation, Self-Diffusion and Microimaging (Ba and Kornfield)
Ir and Pt Complexes Tethered to Nanoparticles as Singlet Oxygen Sensitizers and Quenchers (Selke and Stoltz)
Flow-Based Fiber Optic Analysis on a Lab-on-Chip Platform (PREM Grant Seed research project - Hanrahan)
Probing peptide side chain interactions using natural and unnatural peptides (PREM Grant Seed research project - McCurdy)
We are developing microfluidic devices (MDs) for novel applications including assays-on-a-chip, the polymerase chain reaction (PCR), microscale column chromatography, flow-injection analysis (FIA), and ACE-through-a-chip. Another important focus is in the development of organic-resistant materials for MDs for use in combinatorial chemistry, assays and detection, and high-throughput synthesis.
Figure 1 (Top) Microfluidic assay device for estimating binding interactions. (Bottom) Magnetic bead derivatization with the glycopeptide antibiotic teicoplanin.
Figure 2 (A). (A) Microcolumn chromatography. Work conducted by PREM student Alvaro Gomez in collaboration with Drs. Axel Scherer and George Maltezo.
Figure 2 (B) Separation of a dye using the microcolumnwith Dr. Axel Scherer of Caltech.
Figure 3. Polymerase chain reaction (PCR) apparatus. Work conducted by PREM student Alvaro Gomez and Drs. Axel Scherer and George Maltezos of Caltech.
Figure 4. Photographs of prototype microfluidic device featuring (A) reagent mixer and (B) bottom section of electrophoresis channel. The fluid layers are 100 micrometers in width and 25 micrometers in height; the control layers are 100 and 200 micrometers in width and 25 micrometers in height.
Movie 1. Sample injection followed by electrophoresis in a prototype microfluidic device. The fluid layer is approximately 140 micrometers in width and 35 micrometers in height. [Note: Apple's Quicktime is required to see this video. For a free copy of Quicktime for Mac or PC, go to Quicktime for Mac or Quicktime for PC.]
We are designing more effective self-assemblies of Fluoroalkyl-ended poly(ethylene glycol) (Rf-PEG) drug-delivery system for use as hydrophobic drug delivery agents. Rf-PEG hydrogels were designed with the biocompatibility and biodegradability in mind. The hydrophobic cores of the micelles formed by the fluoroalkyl-ended groups on both sides of the PEG chains hold together the physical network in an aqueous environment (e.g., in the body), but can dissociate in biocompatible organic solvents to produce a low viscosity, injectable formulation. The coexistence of the gel phase and the sol phase predicts the potential of the Rf-PEG system to be developed as delivery depot to release hydrophobic drugs to body with sustained and controlled release rates. The overall goal of this research is to elucidate the fundamental mechanisms of drug delivery by means of NMR techniques of relaxation, self-diffusion and microimaging for designing effective Rf-PEG drug-delivery system.
Figure 1. Erosion of the gel phase to the sol phase for a sol-gel coexistence system from a surface.
Â Â Â Â Â Â Â Â Â Â Â We are investigating nanocomposite materials containing a variety of phosphorescent Pt(II) and Ir(III) cyclometallated complexes and their photophysical properties, especially the ability to act as sensitizers and quenchers of singlet dioxygen. One of the major aims of this project is the construction of novel photosensitizer (PS) entrapped nanocomposites for photodynamic therapy (PDT).
Figure 1. (a) Schematic diagram of synthetic routes of PS-loaded nanoparticles; (b) Schematic representation of conjugating antibody to PS-entrapped copolymer nanocapsule.
Flow-Based Fiber Optic Analysis on Lab-on-Block
and Lab-on-Chip Platforms
Figure 1. Photograph of the prototype lab-on-block
FI-CE system employing fiber optic detection.
Our PREM research focuses on the design and development of flow-based analytical systems employing fiber optics on lab-on-block and lab-on-chip formats for the determination of trace metals and biomolecules. We also employ chemometric tools for experimental design, instrument optimization and data interpretation.
We are investigating some of the noncovalent forces found in protein structures, such as the cation-pi interaction. Results from these fundamental studies will guide the development of materials with useful properties. Our approach is to perform âChemical Mutagenesisâ on synthetic helical peptides followed by structural studies using circular dichroism and NMR spectroscopy. These studies will ultimately result in a better understanding of these noncovalent forces, with applications in materials, protein, and pharmaceutical design.