Biophysics
Biophysics is the bridge between biology – which studies life in all its variety and complexity – and physics – which seeks out the mathematical laws and patterns that make nature’s physical existence both understandable and predictable. From Watson and Crick’s 1953 discovery of the structure of DNA to today’s ultra-fast “gene-chip” technologies, biophysicists study life at every level, from atoms and molecules to cells, organisms, and environments.
At Bar-Ilan University, a significant number of scientists devote themselves to the study of the membrane – the living “fence” that encircles cells and sub-cellular organelles, stabilizing them energetically and mediating interactions with the outside environment. Other laboratories focus on characterizing fundamental signaling mechanisms in cells, or on quantifying the forces that affect individual proteins. Finally, Bar-Ilan biophysicists are creating important new tools for the observation, measurement and manipulation of biological processes. This “critical mass” of biophysics-oriented researchers is why Bar-Ilan is home to the only undergraduate and graduate study programs in biophysics that are approved by Israel’s Council of Higher Education.
From drug discovery to disease prevention, from medical imaging to forensics, and from energy research to environmental protection, Bar-Ilan biophysicists are revealing the patterns and principles behind the dynamic process we call life. Their discoveries are creating hope that – in the not-too-distant future – life will be healthier than ever before.
Biophysics Research: Enhancing PDT
Ehrenberg's team has demonstrated that PDT can be enhanced by chemically modifying the molecule so that it will be located deeper in the membrane and will cause greater damage, because the singlet oxygen species that are formed need to travel just a few more nanometers before they escape out of the membrane.
They are currently exploring novel methods for enhancing photosensitization, including the coupling of photosensitizer molecules to quantum dots (Qdots) or to semiconducting polymer dots (Pdots).
Biophysics Research: Studying DNA-Protein Interactions
Garini and his research team are studying variations in the mechanical conformations induced by the nucleoid-associated protein HU. They use two different approaches to detect variations in the dynamics and conformations of single DNA molecules due to HU binding.
The first approach, Tethered Particle Motion (TPM), allows them to detect the dynamic variations in the end-to-end distance of single DNA molecules due to the bending/unbending activity of HU. In their TPM setup, a small nanobead is attached to a linear dsDNA at one end, while the other end is attached to the surface. Illuminating the sample makes it possible to detect the scattered light from the gold nanobead. In addition, a higher signal-to-noise ratio is achieved using dark field illumination.
The bead diffuses in a restricted volume, which varies in the presence of a protein. In their second approach, they use an Atomic Force Microscope (AFM) to better understand the structural details of the HU-DNA complexes. They identify angle distributions for different concentrations and calculate the cumulative distribution function (CDF).
