Space Radiation.

Wise Labs has begun working on quantification of photonic behavior in Two-Photon Microscopy. This has led to other collaborations with Dr Boukari of the Section on Cell Biophysics in quantifying photon behavior in the case of Fluorescence Correlation Spectroscopy. It ties in well with another project we have ongoing in collaboration with Dr Ilev . These recent developments in Two-Photon imaging have been aimed at pushing back the depth limit of this exciting imaging technique. Here at Wise Labs have been working in collaboration with a group at National Heart Lung Blood Institute led by Dr Balaban. This work has involved the development and quantification of a new approach to enhance Two-Photon microscopy. The basic tenet of the approach is to obtain Total Emission Detection (TED), as opposed to the usual exome sequencing project to subjected space radiation.

Wise Labs has implemented into developed space module a simple emission-only fluorescence Monte-Carlo model. Here we are sealing with scattered light as we are handling light emitted through tissue so a photonic model is used. We can safely ignore the diffraction blurring caused as we are at the boundary of photonic or wave behavior of light as we are only considering the Gain of the instrument. Initial results from our algorithm were shown to match well with data from a phantom study (given a scaling factor based on known instrumental losses due to efficiency of optical components), as shown in figure a. In figure b we show some initial calibration of the instrumental effectiveness in different tissue types at different depths. This has has led to further work being done in collaboration with the section on Cell Biophysics. Here are helping to quantify the effects of scattering.

Fluorescence Correlation Spectroscopy in FCS it is common to use micro-beads to examine diffusion rates of a molecule, however at this time the effect this has on the imaging is not properly considered. It is generally noted that some blurring will occur, but no quantification of this is currently available. To examine this we have created a second Monte-Carlo simulation looking at the source fieled for a con-focal instrument. We have noted that the effects of scatter on an FCS illumination field are more complex than just blurring. The scattering (and relative anisotropy) have significant effects on the shape and location of the illuminated region. This implies effects on both where we are looking, but may also change the relative volumes under consideration, an effect which may bias the diffusion rate being monitored. In the figure below we show how scattering can completely destroy the confocal spot, and how relatively high anisotropy factors can reduce this effect. It becomes important then to understand the size and refractive index of the microbeads used and how these will affect the illumination field in FCS.