Department of complex matter

Biophysics and Biomedical optics

Biophysics research at our department includes experimental studies of molecular motors and protein manipulation with optical tweezers and investigation of electron dynamics in DNA using optical spectroscopy. Biomedical optics and engineering involves studies of laser-tissue interaction and development of novel laser-based diagnostic and therapeutic applications.

 

 

 

Quantum proceses on DNA

We study quantum processes in biological macromolecules using optical experimental methods e.g. infrared, photoinduced infrared, Raman and UV/Visible spectroscopy. The photoinduced infrared spectroscopy is particularly useful in the research of charge dynamics and localization in DNA, were charge-vibration interactions could be detected and identified. These techniques are complementary to the more usual scanning probe microscopy techniques which are used for investigations of single molecules.

Photoinduced IR Spectroscopy

In the photoinduced IR spectroscopy we measure the difference in the IR light transmittance with a laser excitation  on and off DT = (Ton – Toff) / Toff. Periods of the on/off cycle are typically 1 to 10 s, but could be reduced down to few tenths of ms. The aim of the photexcitation is a formation of additional free charge carriers in a system. Those carriers couple with molecular vibrations and cause shifts or additional absorption peaks in a molecule’s vibrational spectrum. From position and magnitude of spectral shifts or new absorptions we can identify mechanism and strength of the charge-lattice interactions.

Scheme of the Photoinduced IR Absorption Experiment

References

Hole interactions with molecular vibrations on DNA. OMERZU A., LIČER M., MERTELJ T., KABANOV V.V., MIHAILOVIĆ D., Phys. Rev. Lett. 93, 218101-1 (2004).

 

Kinetics of molecular motors

Stepping kinetics of molecular motor myosin V is investigated, using optical tweezers setup. This work is done in collaboration with Matthias Rief’s Group at the TUM, Germany.

 

 

 

Biomedical Optics

We are investigating the potential of pulsed photothermal radiometry for high-resolution depth profiling and tomographic imaging of strongly scattering biological tissues, in particular for characterization of dermatologic vascular lesions (such as port wine stain birthmarks) in vivo.
Interaction of high intensity radiation with biological tissue, e.g. ablation of hard and soft tissues with mid-infra red lasers, is studied at microscopic and macroscopic levels.
In collaboration with Beckman Laser Institute and Medical Clinic, University of California at Irvine.

 

Laser therapy

Advances in existing and possibilities for novel laser therapies (primarily in dermatology, aesthetic surgery and stomatology) are investigated in numerical, in vitro, and clinical studies.
In collaboration with company Fotona (Ljubljana), Clinical Center Ljubljana, and Beckman Laser Institute and Medical Clinic, University of California at Irvine.

 

 

Biomedical engineering

We investigate dynamic cooling with millisecond sprays of cryogenic liquid for application in dermatologic laser therapy. We participated in development of a cell culture model of human skin and its application in testing of novel laser therapies.
In collaboration with Beckman Laser Institute and Medical Clinic, University of California at Irvine.

Biophysics and Biomedical optics
Biophysics and Biomedical optics
Biophysics and Biomedical optics
Biophysics and Biomedical optics
Biophysics and Biomedical optics
Biophysics and Biomedical optics