Grant: Research Tools and Instruments - Category 1 (<$150,000)

Absorption and emission spectroscopy together permit the characterization of both ground and excited state molecular properties.  Once known, these properties constitute the optical signature of a molecule, and changes in this optical signature as a function of molecular environment provide a wealth of information regarding the nature of both electronic and molecular interactions.  Purchase of an absorption-emission spectroscopy system is proposed to  characterize the ground and excited state properties of new DNA photocleaving agents for use in photodynamic therapy (PDT), a treatment for certain cancers as well as age-related macular degeneration.  DNA photocleaving agents are artificial nucleases that introduce single- or double-strand breaks in the DNA backbone upon photoactivation with an appropriate wavelength of light.  The design of new agents must address current limitations:  (i) requirement for molecular oxygen to function, (ii) lack of double-strand cleaving capacity, and (iii) maximal absorption outside the phototherapeutic window (700-900 nm).  The proposed absorption-emission system is required to characterize fully the photophysical properties of new DNA photocleaving agents and to investigate their interactions with DNA.  This knowledge is essential to outlining the mechanistic aspects of new DNA photocleaving agents and evaluating their potential as candidates for PDT in the context of those limitations outlined previously.      This absorption-emission system is also required by four additional co-applicants.  Two of these are collaborators that wish to determine whether the cytotoxicity demonstrated by their designed molecules stems, in part, from direct interaction with the DNA backbone.  Co-applicants with unrelated research projects will use the instrument for fluorescence monitoring of environmental trace metals and absorption and fluorescence characterization of photocages.  The lack of dedicated absorption and fluorescence spectrometers for research in the Chemistry Department at Acadia University further necessitates the acquisition of the proposed absorption-emission system.