Applications of light and lasers in medical pre-clinical and clinical research

Dr. Lilge's research is focused on enabling/improving: 1) the use of light for clinical diagnostic and/or therapeutic applications; and 2) the use of light as a microscopic tool for biomedical research.

An example of optical medical diagnostics is the use of transillumination spectroscopy combined with numerical biostatistical methods to quantify cancer risk. This work is based on the theory of tissue field transformation prior to the development of dysplasia and carcinoma in situ. To establish optical transillumination as a cancer risk assessment tool cross sectional clinical studies are underway or planned using an established epidemiological marker as a gold standard. In the case of breast cancer this marker is the parenchymal density pattern as observed in standard mammography. Transillumination spectra show high sensitivity and specificity to classify women as having high or low parenchymal density pattern. Another potential application for this technology are risk determination for various neurological deficiencies.

An example for ongoing work towards clinical optical therapeutics is to increase the efficacy of photodynamic therapy (PDT) by enabling treatment monitoring using fiber optical probes. In this cancer treatment modality, light activated drugs produce extremely short lived cytotoxic substances. To date three parameters (molecular oxygen, light radiance and drug concentration) are identified to govern the treatment's efficacy. By controlling the local light intensity online, the production of cytotoxic substances can be adjusted, based on the available oxygen and photosensitizer to maximize the tumoricidal effect while sparing normal healthy tissue.

The project includes the development of interstitial sensors based on optical fibre technology and quantification of the biological in vivo response in different tissues. The long term goal of this research aims to enable a selective apoptotic or necrotic responses in the tumour.

The biochemical pathways activated in various cell lines are investigated in a separate project using confocal laser scanning microscopy and fluorescent antibodies towards identified proteins in apoptotic pathways. Of special interest is the so-called bystander effect which suggests that cells react as an ensemble PDT.

Optical micro manipulating tools for biomedical research comprises the combination of tools such as optical tweezers, optical scissors, chromophore assisted laser inactivation and capillary elecrophoresis, to sort, manipulate and detect cells and/or biological macromolecules including proteins, DNA and mRNA. Integrated optical solutions for cell culture and biopsy analysis as an alternative to flow cytometry, ELISA or electrophoresis are sought.

For a list of Dr. Lilge's publications, please visit PubMed, Scopus or ORCID.

Professor, Department of Medical Biophysics, University of Toronto