• Antibody-drug conjugates
• Targeting platform – 'OptiLink'
• Light activated cancer therapy – 'ProstaLite'
• MRI contrast agents & imaging
• Photosensitiser innovations
• Additional products and applications

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Photosensitiser Innovations

PhotoBiotics' research has also led to significant advances in the chemical design of effective photosensitisers for light-activated cancer therapy. Four patent-protected key innovations incorporate:

• 'Core' modification = enhanced photophysics for better cell killing

• Triple bonds = improved depth penetration of light into tissues

• Hydrophilic groups = enhanced photosensitiser formulation and delivery

• A pre-designed reactive group = ease of photosensitiser conjugation to scFvs

Additionally, PhotoBiotics' research on several PICs demonstrates how fine-tuning certain photosensitiser features brings added benefits. Using commercially available photo-sensitisers, PhotoBiotics has shown how particular improvements to photosensitiser hydrophilicity suppress:

• Aggregation and precipitation, which are significant problems associated with current water soluble photosensitisers

• Non-covalent binding of photosensitisers to scFvs during conjugation

These significant improvements in photosensitiser manufacturing lead to increased reproducibility and yields of PICs, which retain all the excellent photophysical properties of the original photosensitiser molecules.

In addition, PhotoBiotics’ PIC technology vastly improves the LD50's of some third-party commercially-available photosensitisers (see Scientific Publications; Photochemical and Photobiological Sciences, 2007;6:933-939). Thus, using OptiLink technology, a PIC made with verteporfin (the photosensitiser used in Visudyne for treating of Age-Related Macular Degeneration (AMD)), has shown a resultant 13-fold increase in specificity and 7-fold increase in potency compared to verteporfin alone.

PhotoBiotics is currently incorporating these innovations into a new patentable generation of photosensitiser derivatives readily produced through robust, commercially viable syntheses.