David Walt

David R. Walt

Department of Chemistry
Pearson Chemistry Laboratory
62 Talbot Avenue
Tufts University 
Medford, MA 02155 

Office: P-309

Tel: 617-627-3470   Fax: 617-627-3443

E-mail: david.walt@tufts.edu 

Research Homepage

Current Appointments


University Professor
Howard Hughes Medical Institute Professor
Adjunct Professor of Biomedical Engineering




Postdoctoral Research Associate, 1979-81, Massachusetts Institute of Technology, Cambridge, MA
Ph.D., 1979 (Chemical Biology), SUNY at Stony Brook, Stony Brook, New York
B.S. 1974 (Chemistry), University of Michigan, Ann Arbor, Michigan


Research Interests

Bioanalytical Chemistry, Materials Chemistry, Biochemistry and Nanoscience.  The Walt group's research effort employs optical fiber microarrays for the detection and analysis of single molecules. Single enzyme molecules are enclosed with fluorogenic substrate in an array of thousands of individually addressable microchambers etched into a glass optical fiber bundle. The large array size provides excellent statistics. The substrate turnover in the microchambers can be monitored with fluorescence microscopy. The results of these experiments provide mechanistic insight into enzyme mechanisms. In addition to these fundamental studies, they have also developed single molecule methods for high sensitivity DNA and protein detection. In another project the Walt lab is investigating the limits to creating high-density sensing arrays containing thousands of microsensors and nanosensors and are preparing arrays to perform high density nucleic acid and protein analysis. One application of this effort is an integrated diagnostic platform for performing medical diagnostics using saliva as a sample instead of blood. The arrays can also be used to study living cells, both as cell populations as well as individual cells, and analyze the contents of individual cells by integrating microfluidics with single molecule detection. They are also studying the behavior of large numbers of cells to understand the distribution of cell behaviors in a population.l


Selected Recent Publications


“Protein Counting in Single Cancer Cells”, S.M. Schubert, S.R. Walter, M. Manesse, D.R. Walt, Analytical Chemistry, 2016, 88(5), 2952-2957.


“Incorporation of SOMAmer® Reagents in Single Molecule Array (Simoa) Assays for Cytokine Detection with Ultra-high Sensitivity”, D. Wu, E. Katilius, E. Olivas, M. Dumont Milutinovic, D.R. Walt, Analytical Chemistry, 2016, 88(17), 8385-8389.


“Rapid and Ultrasensitive Single Molecule Detection of Botulinum Neurotoxin Serotype A1 in Human Serum and Urine using Single Molecule Array Method”, T.L. Dinh, K.C. Ngan, C.B. Shoemaker, D.R. Walt, Forensic Toxicology, 2016.


"Single Molecule Arrays (Simoa) for the Ultra-Sensitive Detection of the Host Immune Response to Dengue Infection", S. Gaylord, S. Abdul-Aziz, D.R Walt, Journal of Clinical Microbiology, 2015, 53, 1722-1724.


“Fiber-Optic Array Using Molecularly Imprinted Microspheres for Antibiotic Analysis”, S. Carrasco, E. Benito-Peña, D.R. Walt, M.C. Moreno-Bondi, Chemical Science, 2015, 6, 3139-3147.


“Ultra-Sensitive Detection of Ricin Toxin in Multiple Sample Matrices Using Single Domain Antibodies", S.T. Gaylord, E.R. Goldman, T. Dinh, G.P. Anderson, D.R. Walt, Analytical Chemistry, 2015, 87, 6570-6577.


“Ultra-sensitive protein detection via single molecule arrays towards early stage cancer monitoring”, S.M. Schubert, L.M. Arendt, W. Zhou, S. Baig, S.R. Walter, R.J. Buchsbaum, C. Kuperwasser, D.R. Walt, Scientific Reports, 2015, 5, 11034.


“Single Molecule Array (Simoa) Assay with Optimal Antibody Pairs for Cytokine Detection in Human Serum Samples”, D. Wu, M. Dumont Milutinovic, D.R. Walt, Analyst, 2015, 140, 6277-6282.


“Correlations of Salivary Biomarkers with Clinical Assessments in Patients with Cystic Fibrosis”, S. Nie, H. Zhang, K.M. Mayer, F.G. Oppenheim, F.F. Little, J. Greenberg, A.Z. Uluer, D.R. Walt, PLOS One, 2015, 10(8), e0135237.

"Stoichiometry of the α-Complementation Reaction of Escherichia coli β-Galactosidase As Revealed through Single-Molecule Studies." Mogalisetti, P., Walt, D., Biochemistry, 2015, 54, 1583-1588.


“Training the Next Generation of Biomedical Investigators in Glycosciences”. P. Agre, C. Bertozzi, M.J. Bissell, K. Campbell, R. Cummings, U. Desai, M. Estes, T. Flotte, G. Fogleman, F.H. Gage, D. Ginsburg, J. Gordon, G. Hart, V. Hascall, L.L. Kiessling, S. Kornfeld, J.B. Lowe, J. Magnani, L. Mahal, R. Medzhitov, R.J. Roberts, R. Sackstein, R. Sarkar, R. Schnaar, N. Schwartz, A. Varki, D. Walt, I. Weissman, National Heart Lung and Blood Institute Working Group Meeting, 15 April 2015, Bethesda, MD. Journal of Clinical Investigation, 2015, 126, 405-408.


"Disease Detection by Ultrasensitive Quantification of Microdosed Synthetic Urinary Biomarkers" Warren, A., Gaylord, S., Ngan, K., Milutinovic, M., Kwong, G., Bhatia, S., Walt, D.,

J. Amer. Chem. Soc., 2014, 136, 13709-13714.


"Measuring Atomic Emission from Beacons for Long-Distance Chemical Signaling"

LaFratta, C., Pelse, I., Falla, J. L., Palacios, M., Manesse, M., Whitesides, G., Walt, D.,

Anal. Chem., 2013, 85, 8933-8936.


"Optical Methods for Single Molecule Detection and Analysis", David R. Walt,

Anal. Chem., 2013, 85, 1258–1263.


"InfoBiology by printed arrays of microorganism colonies for timed and on-demand release of messages", M. A. Palacios, E. Benito-Peña, M. Manesse, A. D. Mazzeo, C. N. LaFratta, G. M. Whitesides, and D. R. Walt, Proc Natl Acad Sci USA, 2011, 108, 16510-16514.


"Detection and Classification of Ignitable Liquid Residues using a Fluorescence-Based Vapor-Sensitive Microsphere Array", M. J. Aernecke, D. R. Walt, J. Forensic. Sci., 2010, 55, 178-184.

"Synthesis and Biological Testing of Penicillins: An Investigative Approach to the Undergraduate Teaching Laboratory" , R. D. Whitaker, L. Truhlar, D. Yuksel, D. R. Walt, M. Williams, J. Chem. Edu.2010, 87, 634-636.


"Analytical Chemistry on the Femtoliter Scale", H. H. Gorris, and D. R. Walt.

Ang. Chemie, 2010, 49, 3880-3895.


"Visualizing Fluorescence: Using a Homemade Fluorescence 'Microscope' to View Latent Fingerprints on Paper" C. N. LaFratta, D. R. Walt, S. P. Huh, A. Mallillin, and P. Riviello.

J. Chem. Edu., 2010, 87, 1105-1107.


"Single-molecule enzyme-linked immunosorbent assay detects serum proteins at subfemtomolar concentrations", D. M. Rissin, C. W. Kan, T. G. Campbell, S. C. Stuart, D. R. Fournier, L. Song, T. Piech, P. P. Patel, L. Chang, A. J. Rivnak, E. P. Ferrell, J. D. Randall, G. K. Provuncher, D. R. Walt, D. C. Duffy, Nature Biotechnology, 2010, 28, 595-599.


"Optical-fiber arrays for vapor sensing", Aernecke, Matthew J.; Walt, David R. Sensors and Actuators, B: Chemical, 2009, B142, 464-469.


"Infochemistry and infofuses for the chemical storage and transmission of coded information" Thomas, Samuel W., III; Chiechi, Ryan C.; Lafratta, Christopher N.; Webb, Michael R.; Lee, Andrew; Wiley, Benjamin J.; Zakin, Mitchell R.; Walt, David R.; Whitesides, George M. Proc. Natl. Acad. Sci. USA, 2009106, 9147-9150.

"Intelligent Medical Diagnostics via Molecular Logic", Konry, Tania; Walt, David R., J. Amer. Chem. Soc.,
2009, 131, 13232-13233.

Additional publications can be found HERE

Selected Media & E/PO Links

- BBC News "Fluorescing Bacteria Used to Encode Secret Messages" 27 Sept 2011


- ACS Webinar "A Life of Inovation - Finding Your Passion" David Walt 17 June 2010


- "Working with Local Public Schools" Tufts Daily, 31 March 2010


- Observing Single Enzymes At Work Chem. Eng. News, 29 Oct 2007