Thomas Group -  Biophysics

 

Our research focus is the application of optical and fluorescence techniques to study biological and biomaterial systems at the subcellular level. We are currently working on three projects:

 

Fluorescence and optical techniques to measure the ultrasound-driven release of drug mimics from liposomes and lipid-coated bubbles (Andy Maloney)

 

Fluorescence correlation spectroscopy, and applications using local field enhancement (Fang Huang)

 

4-Wave Mixing Microscopy (in collaboration with W. Rudolph, UNM Physics and Astronomy) (Xuejun Liu)

The laboratory is also the UNM host site for a Raydiance Desktop USPTM R&D laser. The Raydiance is a pulsed (~700 fs, 500 kHz) laser with up to 5 microJoules of energy per pulse. More information on the laser capabilities may be found in this PowerPoint presentation.

 

 

Researchers in the UNM community are welcome to use this laser for pilot research projects. Please contact Dr. Thomas to discuss your application.

 

 

Ultrasound-Mediated Release of Entrapped and Adsorbed Drugs

 

Using a Sonic Concepts 1.1 MHz transducer, we are studying whether high-frequency, focusable ultrasound can effectively release drug mimic compounds from liposomes and lipid-coated bubbles. Very strong ultra-sound also causes sonoluminescence, through cavitation collapse. Somewhat paradoxically, in a focused sound field sonoluminescence is not strongest at the focus. The exact relationship between sonoluminescence and lipid membrane permeabilization has not been clearly established.

 

 

Fluorescence Ratio System

 

 

 

 

 

 

US Sonoluminescence / Sample Chamber

 

 

Andy Maloney

 

 

 



Fluorescence Correlation Spectroscopy

 

Fluorescence correlation spectroscopy is a well-established technique for determining both diffusion coefficients and associations of biomolecules in cells.

 

We are using FCS in a collaboration with Prof. Diane Lidke of the School of Medicine to measure association of a signal transduction kinase in the cytoplasm.

 

We are also exploring local field enhancement from metal island arrays to restrict FCS sampled volumes, and to study correlations in multiphoton signals, such as second harmonics.

 

 

FCS Microscope

Gold Island Array

(Bar= 2mm)

Satish Kasarla, Los Alamos

 

 

Fang Huang