With the COVID-19 pandemic continuing to dominate life across the globe, RaNT went out on-demand, to hundreds of work-from-home desks at this weeks’ virtual SciX2020.
Conference delegates watched invited talks from Dr. Sara Mosca and Dr. Ben Gardner in on-demand sessions available online throughout the week.
As RaNT’s resident deep-Raman experimental experts, Sara and Ben’s talks each gave a comprehensive overview of the surface enhanced, spatially offset and transmission Raman spectroscopy techniques being developed as future clinical diagnostic technologies.
They discussed the non-invasive application of these techniques to localised, deep-tissue temperature measurements, and updated the audience on development of RaNT’s SESORS approach to accurately measuring depth of gold nanoparticles buried in thick tissue.
This builds on Sara’s talk at SciX2019.
Dr. Mosca and Dr. Gardner will continue to take questions from all time-zones whilst the Q&A remains open over the coming days.
See their conference abstracts below.
This was Ben’s first official outing as a member of the RaNT team; but as a long-serving member of Prof. Nick Stone’s BioSpec research group at the University of Exeter, Dr. Gardner’s work on deep-Raman spectroscopy has been instrumental in laying the groundwork for Raman Nanotheranostics.
It’s great to finally welcome him to the RaNT crew.
Non-invasive Determination of Depth of Inclusion in Ex vivo Tissues using Deep Raman Spectroscopy
Author: Sara Mosca, Priyanka Dey, Francesca Palombo, Nick Stone & Pavel Matousek
In a clinical context it is beneficial to identify both the chemical information and the depth of a buried object in biological tissues. For example, the in vivo identification and localisation of a cancer lesion located deep inside biological tissues could potentially facilitate more accurate spectroscopic diagnosis or improve the effectiveness of subsequent treatments.
Here we demonstrate the use of spatially offset (SORS) and transmission Raman (TRS) spectroscopy for non-invasive depth prediction of an inclusion, made up of surface-enhanced Raman scattering (SERS) labelled nanoparticles (NPs), buried inside ex-vivo porcine tissues. The concept exploits the differential attenuation of two Raman bands of the inclusion due to their different absorption by surrounding tissue matrix to retrieve depth information. The relative degree of the Raman band intensity changes are directly related to the path-length of Raman photons travelling through the medium thereby encoding also the information on the depth of the object within the tissue. The calibration model for depth prediction is created using data only from external measurements carried out in SORS and TRS configurations. Monte Carlo simulations of the photon propagation in the two different geometries confirm the relationship between the spatial offset and the phonon path length inside the tissues. These approach was tested and evaluated for predicting the depth of the SERS NPs, within an up to 40 mm slab of ex-vivo porcine tissue yielding an average root mean square error of prediction of total depth of 6.7 % for TRS and 11 % for SORS.
Our results pave the way for future non-invasive deep Raman spectroscopy in vivo enabling to localize cancer biomarkers for early disease diagnosis and targeted treatments.
Surface Enhanced Deep Raman Spectroscopy (SEDRS): Quantification of Physical properties at depth, advances and pitfalls
Author: Ben Gardner, Nick Stone & Pavel Matousek
Deep Raman Spectroscopy (DRS), the grouped term for spatially offset Raman spectroscopy (SORS) and Transmission Raman (TRS), has shown great promise in the biomedical domain; especially for its potential in areas such as non-invasive diagnostics combined with therapeutic interventions (theranostics). The capabilities and complexities of what is possible using these techniques has steadily increased over the past decade, especially with the introduction of labelled nanoparticles allowing Surface Enhanced Raman Spectroscopy (SERS) to be combined with DRS (SEDRS), to allow deeper and specific signal recovery, as well as targeting specific physical properties / chemical moieties (pH, temperature, glucose sensing and neurotransmitters) to name but a few. Here we highlight the latest advances in SEDRS, looking at multiple simultaneous signal recovery including accurate depth localisation; as well as new developments in non-invasive temperature sensing and modulation i.e. heating and the experimental complications associated with monitoring and validation of this process.