Publications by Year: 2014

2014
Photosensitizer fluorescence and singlet oxygen luminescence as dosimetric predictors of topical 5-aminolevulinic acid photodynamic therapy induced clinical erythema.
S. Mallidi, et al., “Photosensitizer fluorescence and singlet oxygen luminescence as dosimetric predictors of topical 5-aminolevulinic acid photodynamic therapy induced clinical erythema.Journal of Biomedical Optics, vol. 19, pp. 028001, 2014. Publisher's VersionAbstract

The need for patient-specific photodynamic therapy (PDT) in dermatologic and oncologic applications has triggered several studies that explore the utility of surrogate parameters as predictive reporters of treatment outcome. Although photosensitizer (PS) fluorescence, a widely used parameter, can be viewed as emission from several fluorescent states of the PS (e.g., minimally aggregated and monomeric), we suggest that singlet oxygen luminescence (SOL) indicates only the active PS component responsible for the PDT. Here, the ability of discrete PS fluorescence-based metrics (absolute and percent PS photobleaching and PS re-accumulation post-PDT) to predict the clinical phototoxic response (erythema) resulting from 5-aminolevulinic acid PDT was compared with discrete SOL (DSOL)-based metrics (DSOL counts pre-PDT and change in DSOL counts pre/post-PDT) in healthy human skin. Receiver operating characteristic curve (ROC) analyses demonstrated that absolute fluorescence photobleaching metric (AFPM) exhibited the highest area under the curve (AUC) of all tested parameters, including DSOL based metrics. The combination of dose-metrics did not yield better AUC than AFPM alone. Although sophisticated real-time SOL measurements may improve the clinical utility of SOL-based dosimetry, discrete PS fluorescence-based metrics are easy to implement, and our results suggest that AFPM may sufficiently predict the PDT outcomes and identify treatment nonresponders with high specificity in clinical contexts.

Shining light on the dark side of imaging: excited state absorption enhancement of a bis-styryl BODIPY photoacoustic contrast agent.
M. Frenette, et al., “Shining light on the dark side of imaging: excited state absorption enhancement of a bis-styryl BODIPY photoacoustic contrast agent.Journal of the American Chemical Society, vol. 136, pp. 15853–15856, 2014. Publisher's VersionAbstract

A first approach toward understanding the
targeted design of molecular photoacoustic contrast agents
(MPACs) is presented. Optical and photoacoustic Z-scan
spectroscopy was used to identify how nonlinear (excitedstate)
absorption contributes to enhancing the photoacoustic
emission of the curcuminBF2 and bis-styryl
(MeOPh)2BODIPY dyes relative to Cy3.