Presentation on theme: "Molecular Photoacoustic Contrast Agents"— Presentation transcript:
1 Molecular Photoacoustic Contrast Agents BODIPY Derivatives asMolecular Photoacoustic Contrast AgentsSamir Laoui,1 Seema Bag,2 Olivier Dantiste,1 Mathieu Frenette,2 Maryam Hatamimoslehabadi,1 Stephanie Bellinger-Buckley,2 Jen-Chieh Tseng,3 Jonathan Rochford,2 Chandra Yelleswarapu13Lurie Family Imaging Center, Dana-Farber Cancer Institute, Boston, MA2 Department of Chemistry,1 Department of Physics,University of Massachusetts Boston, Boston, MAThis work is supported by UMass Boston and DF/HCCNIH U54 Minority Institution/Cancer Center Partnership Grant-1U54CA156732/4
2 Outline Motivation Background Properties Bodipy derivatives PAZ-Scan DataConclusion and future work
3 MotivationPhotoacoustic imaging/tomography (PAI) is an in vivo, non-ionizing imaging modality, that can provide location & metabolic activities of tumors with the help of contrast agents.To date, a variety of near-infrared (NIR) absorbing fluorophores, e.g. IRDye800CW, AlexaFluor 750 and ICG, have been used as exogenous contrast agents for deep tissue imaging.Such contrast agents were originally designed for fluorescent imaging applications and are thus optimized as such with a relatively poor photoacoustic response, their only redeeming feature being their excellent optical absorption in the biological transmission window of 600 – 1100 nm.
5 Background - the photoacoustic effect LIGHT SOUND The photoacoustic effect (conversion of light into sound)was published in 1880 by Alexander Graham Bell
6 Desired Physical Properties of MPACs Strong light absorption (emax) in biological transparent window ( nm)Large Stoke’s shift, dissipates excited state energy as heat (DH) via structural reorganization (DV)A photoacoustic signal is basically a photoinduced heat + pressure wave
7 Desired Physical Properties of MPACs Strong light absorption (emax) in biological transparent window ( nm)Small Stoke’s shift, very sharp excitation and emission peak, high fluorescence quantum yield.BODIPYLarge emax, tunable lmaxHigh ΦfHow to re-direct excited state energy?= Fluorescence Quenching
8 Tuning of BODIPY Photophysics Absorption spectraEmission spectraFc-absorption spectra
9 Optical Characterization of BODIPY Derivatives Variations of BODIPYUV-vis(lmax, nm)ε( M-1cm-1)fwhm( cm-1)EmissionΦFl1-BODIPY5001.205.05100.92-MeOPhBODIPY5680.884.05803-(MeOPh)2BODIPY6401.172.96540.44-FcBODIPY5940.890.75n/a5-Fc2BODIPY6851.101.0
11 PAZ-scan Experiment Nd:YAG Laser, 532 nm (or) OPO laser, 680-980 nm 3 nsec pulse widthUltrasound transducer to measure the photoacoustic signalFiber probe to collect the fluorescence signalOptical detector to measure the transmitted energy
18 ConclusionSuccessfully engineered a PA response from the BODIPY chromophores.Fluorescence quantum yield has been reduced from 0.9 to ~0 and the absorbed energy is channeled through non-radiative decay – increased in PA signal .Current work in progress is to move from using BODIPY derivatives to using Curcumin derivatives.
19 Acknowledgement Dr. Jonathan Rochford Samir Laoui Dr. Maryam HatamimoslehabadiDr. Matthieu FremetteStephanie Bellinger-BuckleyU-54The Graduate Student Association at Umass-Boston