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Stimulated Raman Scattering Applied to Human in Vivo Imaging at Video-Rate. Analytical Chemistry Seminar Jessica Espy January 25 th , 2011. Primarily Highlights B. Sarr, C. Freudiger, J. Reichman, M. Stanley, G. Holtom, and X.S. Xie. Science , 2010: 330 (1368-1370).
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Stimulated Raman Scattering Applied to Human in Vivo Imaging at Video-Rate Analytical Chemistry Seminar Jessica Espy January 25th, 2011 Primarily Highlights B. Sarr, C. Freudiger, J. Reichman, M. Stanley, G. Holtom, and X.S. Xie. Science, 2010: 330 (1368-1370).
Challenges of In Vivo Imaging • Living tissue • Constantly moving • Thick • Mostly Opaque • Complex • Patients • Sensitivity (pain) • Impatient • Online Supplemental Material of Saar, B., et al. Science, 2010: 330 (1368-1370).
In Vivo Imaging: Current Methods Fall Short • Magnetic Resonance Imaging (MRI) • Greater imaging penetration depth • Poor spatiotemporal resolution • Metal implant limitations • Fluorescence Imaging • Toxic dyes and labels required • Coherent anti-stokes Raman scattering (CARS) • Video-rate achieved • Poor sensitivity from nonresonant background • Nonlinear concentration dependence • “MRI of the Body (Chest, Abdomen, Pelvis)”. RadiologyInfo.org. 1/17/2011. http://www.radiologyinfo.org/en/info.cfm?pg=bodymr. • Saar, B., et al. Science, 2010: 330 (1368-1370). • Li, L., et al. Biophysical Journal, 2005: 89, (3480-3490). • Cheng, J.X., et al. Journal of the Optical Society of America B, 2002: 19, (1363-1375).
Review of Raman Spectroscopy Virtual Energy States • Irradiate sample with near-IR monochromatic radiation and collect scattered light • Raman active: change in polarity • Raman intensity directly proportional to active group concentration 43210 Vibrational Energy States ∆E Rayleigh scattering Stoke Raman scattering Anti-Stokes Raman scattering • Colthup, N., Daly, L., and Wilberley, S. Introduction to Infrared and Raman Spectroscopy. New York: Academic Press, Inc., 1975. • Gad, S.C. Pharmaceutical Manufacturing Handbook: Regulations and Quality. New Jersey: John Wiley and Sons, Inc., 2008.
Input Output Virtual State Pump Beam Spontaneous Raman Stokes beam Pump beam Stokes Beam Excited State ∆E Ground State Stimulated Raman Scattering • Pump beam intensity decreases • Stokes beam intensity increases • Saar, B., et al. Science, 2010: 330 (1368-1370). • Freudiger, C., et al. Science. 2008: 322 (1857-1861).
Galvanometric Mirrors 100ns Response Time Aluminum Ring Custom Lock-in Amplifier Photodiode Optical Filter SRS Microscopy Design: Epi-Detection Optical parametric Oscillator Spectral Resolution of 3cm-1 Tunable Pump Beam Mode locked Nd:YVO4 Stokes Beam 1064-nm Modulator Sample • Saar, B., et al. Science, 2010: 330 (1368-1370). • Online Supplemental Material of Saar, B., et al. Science, 2010: 330 (1368-1370). • Freudiger, C., et al. Science. 2008: 322 (1857-1861).
Skin Imaging of Live Mice • Saar, B., et al. Science, 2010: 330 (1368-1370).
Skin Imaging of Live Mice H2O Imaging In Vitro Flow Cytometry • Saar, B., et al. Science, 2010: 330 (1368-1370).
In Vivo Drug Penetration: Retinol Epidermis (60μm) Hair Shaft Protein Lipid Retinol Epidermis(100μm) Sebaceous Gland • Saar, B., et al. Science, 2010: 330 (1368-1370).
In Vivo Drug Penetration: Retinol • Saar, B., et al. Science, 2010: 330 (1368-1370).
SRS in Vivo Small Molecule Penetration: d6-DMSO Statum Corneum Epidermis(100μm) Hair • Saar, B., et al. Science, 2010: 330 (1368-1370).
Other Applications of SRS Surface Image of Tablet • Drug Tablets • Tablet formed by small concentration of active ingredient and excipients • Confirm content uniformity • Chemical reaction movies • Future Goal: • Couple with Endoscopy • Not likely • Legend • Active Ingredient • MCC • DCPA • SSG • MS • Slipchenko, M., et al. Analyst, 2010: 135 (2613-2619). • Harvard University. "New microscopy tracks molecules in live tissue at video rate…”. ScienceDaily 2 December 2010. 12 January 2011 <http://www.sciencedaily.com /releases/2010/12/101202141912.htm>. • Saar, B., et al. Angewandte Chemie International Edition, 2010: 49 (5476-5479)
Figures of Merit • Saar, B., et al. Science, 2010: 330 (1368-1370). • Freudiger, C., et al. Science. 2008: 322 (1857-1861). • Evans, C., et al. Proceedings of the National Academy of Sciences. 2005: 102 (16807-16812). • Saar, B., et al. Angewandte Chemie International Edition, 2010: 49 (5476-5479).
Conclusions • Pros: • Imaging Method • Label-free • Noninvasive • Sensitive • Depth analysis • Acquisition time • 37ms /frame • Real-time adjustments • Cons: • Specificity • Shallow imaging • Up to 100μm • Saar, B., et al. Science, 2010: 330 (1368-1370).
Simulations of Collection Efficiency • Online Supplemental Material of Saar, B., et al. Science, 2010: 330 (1368-1370).
Home-Built Lock-in-Amplifier • 100ns response time • Previous commercial LIA allowed 100μs • All analog • Online Supplemental Material of Saar, B., et al. Science, 2010: 330 (1368-1370).
Skin Imaging of Mice • Saar, B., et al. Science, 2010: 330 (1368-1370).