Optical Bioinstrumentation Laboratory

Waves used for biomedical applications, including optical biosensors, ultrasonic imaging and therapeutic ultrasound.

For additional information, including recent teaching assignments, patents and conference presentations, please visit my HOME PAGE.

Current research projects include:

Planar-Waveguide Fluorescence Immunosensor: The evanescent portion of a waveguided laser beam excites fluorescence when an analyte being measured binds to antibodies immobilized on the surface of a planar waveguide. This homogeneous assay is rapid and does not require operator wash steps. Using disposable cartridges, the system is now being studied as a clinical point-of- care sensor and for biological warfare detection. The project is in collaboration with Prof. Jim Herron.

Ultrasonic Enhancement of Drug Delivery: Ultrasound modifies the release and uptake of drug delivered to tissues. Localizing the action of a drug to targeted tissues increases the effectiveness of the treatment while sparing untargeted tissue. These projects are being carried out in collaboration with Profs. Natalya Rapoport and William Pitt.

Modeling of Therapeutic Ultrasound: Ultrasound can be used as an energy delivery means. It has found use as a drug-delivery modality, in bone healing, and in tissue heating and ablation. To model the path of the ultrasound beam in imhomogeneous tissue, we have developed a numerical technique called the fast hybrid angular spectrum method (HAS). This project is in collaboration with Profs. Bob Roemer, Dennis Parker and Mikhail Skliar.

Below are some selected additional publications that are not listed in the PubMed "Selected Publications" collection (at the very bottom of this page):

-J. D. Andrade, J. N. Lin, V. Hlady, J. Herron, D. A. Christensen, and J. Kopecek, "Immunosensors: Remaining Problems in the Development of Remote, Continuous, Multi-Channel Devices," Biosensor Technology, R. B. Buck, et al., eds., Dekker, 1990.
-J.N. Lin, I.N. Chang, J.D. Andrade, J.N. Herron, and D.A. Christensen, "Comparison of Site-Specific Coupling Chemistry for Antibody Immobilization on Different Solid Supports," Journal of Chromatography, Vol. 542, pp. 41-54, 1991.
-W. Sui, D.A. Christensen, and C.H. Durney, "Extending the Two-Dimensional FDTD Method to Hybrid Electromagnetic Systems with Active and Passive Lumped Elements," IEEE Transactions on Microwave Theory and Techniques, Vol. 40, pp. 724-730, April 1992.
-R.B. Gwynn and D.A. Christensen, "A Method for Accurate Optical Alignment Using Diffraction Rings from Lenses with Spherical Aberration," Applied Optics, Vol. 32, No. 7, pp. 1210-1215, March 1993.
-D.A. Christensen, J. Rotge, A. Klemas, G. Loos, and D. Merriman, "Laser Diode Coherence Length Variation for Balancing Fiber Optic Interferometers,” Optical Engineering, Vol. 33, No. 6, pp. 2034-2038, June 1994.
-D.A. Christensen, T. Johansson, and D. Petelenz, "Biosensor Development at the University of Utah," Engineering in Medicine and Biology, Vol. 13, No. 3, pp. 388-395, June/July 1994.
-D.A. Christensen, "Analysis of Near Field Tip Patterns Including Object Interaction Using Finite-Difference Time-Domain Calculations," Ultramicroscopy, Vol. 57, Nos. 2/3, pp. 189-195, February 1995.
-D.N. Buechler, D. H. Roper, C. H. Durney, and D. A. Christensen, "Modeling Sources in the FDTD Formulation and Their Use in Quantifying Source and Boundary Condition Errors," IEEE Transactions on Microwave Theory and Techniques, Vol. 43, No. 4, pp. 810-814, April 1995.
-T.E. Plowman, W. M. Reichert, C. R. Peters, H. K. Wang, D. A. Christensen, and J. N. Herron, "Femtomolar Sensitivity Using a Channel-etched Thin Film Waveguide Fluoroimmunosensor," Biosensors and Bioelectronics, Vol. 11, No. 1/2, pp. 149-160, 1996.
-C.H. Durney, W. Sui, D. A. Christensen, and J. Zhu, "A General Formulation for Connecting Sources and Passive Lumped-Circuit Elements Across Multiple 3-D FDTD Cells," IEEE Microwave and Guided Wave Letters, Vol. 6, No. 2, pp. 85-87, February 1996.
-D.A. Christensen and D. Fowers, "Modeling SPR Sensors with the Finite-Difference Time-Domain Method," Biosensors and Bioelectronics, Vol. 11, No. 6/7, pp. 677-684, 1996.
-S.D. Dyer and D.A. Christensen, "Dispersion Effects in Fiber Optic Interferometry," Optical Engineering, vol. 36, no. 9, pp. 2440-2447, September 1997.
-T.E. Plowman, J.D. Durtschi, H-K Wang, D.A. Christensen, J.N. Herron and W.M. Reichert, “Multiple-analyte Fluoroimmunoassay using an Integrated Optical Waveguide Sensor,” Analytical Chemistry, vol. 71, pp. 4344-4352, 1999.
-C.M. Furse, D.H. Roper, D.N. Buechler, D.A. Christensen, and C.H. Durney, "The Problem and Treatment of DC Offsets in FDTD Simulations," IEEE Transactions on Antennas and Propagation, vol. 48, pp. 1198-1201, August 2000.
-D.N. Buechler, D.A. Christensen, C.H. Durney and B.J. Simon, “Calculation of Electric Fields in the Human Knee Produced by a Knee-Thigh Electrode Pair,” Applied Computational Electromagnetics Society Journal, vol. 16, no. 2, pp.173-180, July 2001.
-G.A. Husseini, N.Y. Rapoport, D.A. Christensen, J.D. Pruitt and W.G. Pitt, “Kinetics of Ultrasonic Release of Doxorubicin from Pluronic P105 Micelles,” Colloids and Surfaces B: Biointerfaces, vol. 24, no. 3-4, pp. 253-264, 2002.
-G.A. Husseini, D.A. Christensen, N.Y. Rapoport, and W.G. Pitt, “Ultrasonic Release of Doxorubicin from Pluronic P105 Micelles Stabilized with an Interpenetrating Network of N,N-diethylacrylamide,” Journal of Controlled Release, vol. 83, pp. 303-305, 2002.
-N. Rapoport, A. Marin and D. A. Christensen, “Ultrasound-Activated Micellar Drug Delivery,” Drug Delivery Systems and Sciences, vol. 2, no. 2, pp. 37-46, June/July 2002.
-R.D. Rabbitt, H.E. Ayliffe, D. Christensen, K. Parmarthy, C. Durney, S. Clifford and W.E. Brownell, "Evidence of Piezoelectric Resonance in Isolated Outer Hair Cells," Biophysical Journal, vol. 88, pp. 1-9, 2005.
-J.N. Herron, H-K. Wang, L. Tan, S.Z. Brown, A.H. Terry, S.E. Tolley, J.D. Durtschi, E.M. Simon, M.E. Astill, R.S. Smith and D.A. Christensen, "Planar Waveguide Biosensors for Point-Of-Care Clinical and Molecular Diagnostics," Chapter 12 in Fluorescence Sensors and Biosensors (R. B. Thompson, ed.), CRC Press Taylor & Francis Group, Boca Raton, FL, 2006.
-Husseini, Ghaleb A.: Diaz de la Rosa, Mario A.; Gabuji, Tasneem; Zeng, Yi; Christensen, Douglas A. and Pitt, William G., "Release of Doxorubicin from Unstabilized and Stabilized Micelles Under the Action of Ultrasound," Journal of Nanoscience and Nanotechnology , vol. 7, no. 3, pp. 1028-1033(6), March 2007.

Hu N, Christensen DA, Agrawal AK, Beaumont C, Clark EB, Hawkins JA, Dependence of aortic arch morphogenesis on intracardiac blood flow in the left atrial ligated chick embryo. Anat Rec (Hoboken) 2009 May;292(5):652-60

Christensen DA, Herron JN, Optical system design for biosensors based on CCD detection. Methods Mol Biol 2009;503():239-58

Gao Z, Kennedy AM, Christensen DA, Rapoport NY, Drug-loaded nano/microbubbles for combining ultrasonography and targeted chemotherapy. Ultrasonics 2008 Aug;48(4):260-70

Hagmann MJ, Christensen DA, Mousa MS, Baturin A, Sheshin EP, Anomalous high-frequency oscillations in a field emission tube and their significance in pulsed field emission. Ultramicroscopy 2007 Sep;107(9):854-6

Husseini GA, Diaz de la Rosa MA, Richardson ES, Christensen DA, Pitt WG, The role of cavitation in acoustically activated drug delivery. J Control Release 2005 Oct 3;107(2):253-61

Rapoport NY, Christensen DA, Fain HD, Barrows L, Gao Z, Ultrasound-triggered drug targeting of tumors in vitro and in vivo. Ultrasonics 2004 Apr;42(1-9):943-50

Christensen DA, Horch KW, Experience with the first three years of an accelerated dual-degree program in biomedical engineering. Conf Proc IEEE Eng Med Biol Soc 2004;7():5149-51

Tolley SE, Wang HK, Smith RS, Christensen DA, Herron JN, Single-chain polymorphism analysis in long QT syndrome using planar waveguide fluorescent biosensors. Anal Biochem 2003 Apr 15;315(2):223-37

Marin A, Sun H, Husseini GA, Pitt WG, Christensen DA, Rapoport NY, Drug delivery in pluronic micelles: effect of high-frequency ultrasound on drug release from micelles and intracellular uptake. J Control Release 2002 Nov 7;84(1-2):39-47

Buechler DN, Christensen DA, Durney CH, Simon B, Calculation of electric fields induced in the human knee by a coil applicator. Bioelectromagnetics 2001 May;22(4):224-31

Husseini GA, Myrup GD, Pitt WG, Christensen DA, Rapoport NY, Factors affecting acoustically triggered release of drugs from polymeric micelles. J Control Release 2000 Oct 3;69(1):43-52

Dyer SD, Christensen DA, Pupil-size effects in fiber optic stellar interferometry. J Opt Soc Am A Opt Image Sci Vis 1999 Sep;16(9):2275-80

Buechler DN, Durney CH, Christensen DA, Calculation of electric fields induced near metal implants by magnetic resonance imaging switched-gradient magnetic fields. Magn Reson Imaging 1997;15(10):1157-66

Hendee SP, Faour FA, Christensen DA, Patrick B, Durney CH, Blumenthal DK, The effects of weak extremely low frequency magnetic fields on calcium/calmodulin interactions. Biophys J 1996 Jun;70(6):2915-23

Shaw JA, Durney CH, Christensen DA, Computer-aided design of two-dimensional electric-type hyperthermia applicators using the finite-difference time-domain method. IEEE Trans Biomed Eng 1991 Sep;38(9):861-70

Decker-Dunn D, Christensen DA, Vincent GM, Multifiber gradient-index lens laser angioplasty probe. Lasers Surg Med 1990;10(1):85-93