Multimodal sensing of ultra-high-resolution free-electron-mediated modification of biomolecules targeted by metallic nanoparticles
Abstract
The mechanisms of free-electron-mediated modifications of biomolecules (DNA, lipid membranes, and membrane proteins) by femtosecond laser pulses will be investigated with unprecedented spatial resolution and specificity, using novel multimodal sensing techniques and advanced numerical modelling.In the ongoing project FA9550-15-1-0326, results from optical breakdown threshold spectroscopy (OBTS) were used to establish an advanced model of low-density plasma formation in water and laser induced transient cavitation in water and aqueous biological media. The bubble dynamics was explored experimentally by single-shot interferometry with nanometer spatial and < 200 ps temporal resolution. For pulse series, the onset of elevated luminescence was identified as general marker for photomodification in cellular and connective tissues, and as intermediate step in the free-electron-mediated disintegration of biomolecules into volatile decay products that then become detectable as gas bubble. Based on data for wavelength dependent thresholds on fs laser-induced DNA damage, we used our modelling capabilities toidentify free-electron-mediated modification pathways of DNA in the nucleus of living cells.The proposed project will build on these achievements and push the spatial resolution limit by more than one order of magnitude. For this purpose, we use the field enhancement in the vicinity of goldnanoparticles that are irradiated by fs laser pulses at off-resonance IR wavelengths. The two field enhanced regions near a 100-nm nanoparticle irradiated by linear polarized light have a size of 20 nm.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 28, 2018
- Source ID
- FA95501810521
Entities
People
- Alfred Vogel
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Lübeck