Medical adventures in the near-infrared What’s Up In the Biomedical Spectroscopy Lab Andrew Berger The Institute of Optics October 11, 2007

Biomedical Spectroscopy Laboratory members: Rolf Saager, Zach Smith, Brooke Chuzles, Brain and Cognitive Sciences: Prof. Richard Aslin, Dr. Andrea Gebhardt Dept. of Imaging Sciences: Prof. Tom Foster Center for Oral Biology: Prof. Rob Quivey Dept. of Immunology: Prof. Tim Mosmann, Dr. Sally Quaetert Dept. of Pathology: Prof. Bob Mooney Participants and Collaborators

Outline The big picture: biomedical optics and the near infrared Elastic scattering: photon diffusion cerebral monitoring Inelastic scattering: Raman spectroscopy various projects

The grand scheme of things Biomedical Optics observation manipulation alteration

The grand scheme of things observation spectroscopy absorption fluorescence elastic scattering inelastic scattering polarization Biomedical Optics

The near-infrared “window” DNA courtesy V. Venugopalan, electronic vibrational rotational biological window

Outline The big picture: biomedical optics and the near infrared Elastic scattering: photon diffusion infant brain monitoring Inelastic scattering: Raman spectroscopy various projects Rolf Saager

? vision speech motor/sensory hearing

Using light to study blood Absorptivity of Pure Blood (  ) two measurements: absorption per unit length at two wavelengths two unknowns: oxy- and deoxy- hemoglobin concentrations

Noninvasive monitoring of hemodynamics optical power measurements oxy and deoxy hemoglobin concentration changes heartbeat increased blood supply

light in (690, 830 nm) light collected

A problem detector Measurement sensitive to both brain and scalp

A solution? detector Measurement sensitive to both brain and scalp Add a second detector that senses only the scalp second detector Subtract signals to reveal brain-only features?

far Sample near 830 Laser 690 Laser APDs High Speed DAQ Card System Layout 1-10 kHz Modulation    Decoded Wavelength Data 830 Laser 690 Laser Source 1 Source 2 Analog Out DAQ Card

Oh, yeah: Reality Scalp hemodynamics Cerebral Hemodynamics A real head A physicist’s head

Our data…

residual short separation large separation Other people’s raw data… raw data courtesy of Joseph Culver, Washington University

Bring the kids, too!

Outline The big picture: biomedical optics and the near infrared Elastic scattering: photon diffusion infant brain monitoring Inelastic scattering: Raman spectroscopy multiple projects Other projects Brooke Chuzles Zach Smith

Raman scattering incident photon with energy E molecule

Raman scattering molecule gains energy  E scattered photon has energy E -  E incident photon with energy E to detector

Raman Spectrum of a Cell phenylalanine guanine adenine cytosine, uracil phenylalanine C-H 2 def. amide I amide III C-N, C-C str. tyrosine Raman shift (cm -1 ) intensity (arb. units) aromatic amino acids RNA bases

Neutrophil

Peripheral blood mononuclear cell

Angularly-resolved scattering d angular distribution dependent upon size and refractive index mismatch collimated incident light

Inverse telescope Experimental System M CCD S BPF P λ/2 Semrock NF Multi-mode fiber Weak confocal pinhole OD 3 NDF Relay Lens 90° periscope 4% reflector Spatial filter 100 mW 785nm laser Angle Mapped to Position in Fourier plane TV

New system construction: integrating Raman and Angular Scattering Dichroic Beam splitter Long Pass Filter Mirror Kaiser HoloSpec Spectrometer 100μm core optical fiber CCD 150 mW 830nm Diode Laser (MicroLaser Systems) Band Pass Filter Nikon Microscope Video CCD for positioning CCD Fresnel (4%) Reflector ND Filter Samples Key Incident Light Raman Path Elastic Path Key Incident Light Raman Path Elastic Path

Raman spectrum wavenumber shift monocyte neutrophil angular scattering pattern

Raman spectroscopy of biofluids Phenylalanine tyrosine phenylalanine C-C stretching Amide III C-H bending Amide I urea tyrosine Blood serum sample Urine sample T = 150 seconds T = 60 seconds C-O-C stretching

Blood serum: total protein, albumin and globulin 71 samples TP albumin globulin

Urine: UUN (urine urea nitrogen) and creatinine UUNcreatinine

Biologically speaking... Streptococcus sanguis (S. sanguis) Streptococcus mutans (S. mutans) HIGH SUGAR DIET LACTIC ACID

Quantitative Raman measurement of S. mutans concentration in 3-species mixtures Calibration set Validation set Error of calibration: 6.8% Error of validation: 6.7% Project goal: perform similar quantitative analysis of biofilms and plaque specimens ("identify and quantify the bad guys that lead to tooth decay")

Biomedical spectroscopy lab information: AJB office: Goergen Hall 405, , labs:Goergen Hall 433, 435, 436