Texas Tech University

Dr. Dimitri Pappas

Pappas

Title: Associate Professor

Education: Ph.D., University of Florida, 2002
Postdoctoral Study, University of Florida, 2002

Research Area: Analytical Chemistry

Office: Chemistry 300-B

Phone: 806-834-1103

Email: d.pappas@ttu.edu

Webpage: Research Group

Pappas Receives Chancellor's Council Research Award

Pappas is an associate professor in the Department of Chemistry & Biochemistry at Texas Tech. Previously serving as a senior scientist at Johnson Space Center, Pappas has earned national and international recognition for his work using new chemical methods to study and detect illnesses such as heart disease and cancer, and has been noted as one of the top bioanalytical chemists in the nation.
Photos

Principal Research Interests

The Pappas group uses several analytical techniques to study diseases such as sepsis and cancer. In both cases, differences in cell surface protein expression are exploited for disease diagnosis and prognosis. Our group has pioneered the use of three key biomarkers to develop sensitive and selective assay devices for sepsis detection. Our devices have proven highly effective in preliminary clinical studies, and our partnerships in clinics, academia, and industrial continue to make strides toward commercialization of a rapid, early sepsis detection system. Our group also explores transferrin receptor (CD71)-based cell separations for cancer studies. CD71 promises to capture more cancer cells—regardless of phenotype—than other cancer ligands. Our group is exploring devices for cancer cell isolation and subsequent testing.

A new area of inquiry is the application of Super-Resolution Microscopy to expression of these and other biomarkers. Toward that end, we are also developing novel, luminescent nanomaterials for Super-Resolution Microscopy. Our initial core-shell nanosystems have shown strong signal-to-noise and self-blinking behavior. These materials can potentially bring Super-Resolution Microscopy to most laboratories, eliminating the need for complex optics and high-end detectors.

A third component of the Pappas Group is a strong mentoring system. Pappas Group PhD students enter an immersive experience where all aspects of a project are learned. Students graduating from the Pappas group have obtained competitive positions in academic and industry.

Representative Publications

  • Y. Zhou, Y. Zhang, A. Johnson, A. Venable, J. Griswold, D. Pappas , "Detection of Culture-Negative Sepsis in Clinical Blood Samples using a Microfluidic Assay for Combined CD64 and CD69 Cell Capture," Analytica Chimica Acta, (2019).
  • V.J. Lyons, D. Pappas, "Affinity Separation and Subsequent Terminal Differentiation of Acute Myeloid Leukemia Cells Using the Human Transferrin Receptor (CD71) as a Capture Target," Analyst, (2019).
  • M.B. Wickramaratne, M. Ivey, D. Pappas, "Isolation of Proliferating Cells from Whole Blood Using Human Transferrin Receptor in a Two-Stage Separation System," Talanta (2019)
  • C. Chakraborty, S.B. Thompson, C. Snoeyink, D. Pappas, "Modulation and Study of Photoblinking Behavior in Dye Doped Silver-Silica Core-Shell Nanoparticles," Nanotechnology, (2019).
  • Y. Zhang, W. Li, Y. Zhou, A.E. Johnson, A. Venable, A. Hassan, J. Griswold, D. Pappas, "Detection of Sepsis in Patient Blood Samples Using CD64 Expression in a Microfluidic Cell Separation Device," The Analyst, 143, 241-249 (2018).
  • Y. Zhang, Y. Zhou, W. Li, V.J. Lyons, A.E. Johnson, A. Venable, A. Hassan, J. Griswold, D. Pappas, "A Multi-Parameter Affinity Microchip for Early Sepsis Diagnosis Based on CD64 and CD69 Expression and Cell Capture," Analytical Chemistry, 90, 7204-7211 (2018).
  • Z. Dong, D. Yu, Q. Liu, Z. Ding, V.J. Lyons, D. Pappas, X. Liu, W. Li, "Enhanced Capture and Release of Circulating Tumor Cells Using Hollow Glass Microspheres with Nanostructured Surface," Nanoscale, 10, 16795-16804 (2018).
  • W. Li, Y. Zhang, C.P. Reynolds, D. Pappas, "Microfluidic Separation of Lymphoblasts for the Isolation of Acute Lymphoblastic Leukemia using the Human Transferrin Receptor as a Capture Target," Analytical Chemistry, 89, 7340-7347 (2017).
  • D. Pappas, "Microfluidics and Cancer Analysis: Cell Separation, Cell/Tissue Culture, Cell Mechanics, and Integrated Analysis Systems," The Analyst, 141, 525-535 (2016). (Special Issue: Cancer Detection and Diagnosis).
  • W. Li, Y. Gao, D. Pappas, "A Complementary Method to CD4 Counting: Measurement of CD4+/CD8+ T Lymphocyte Ratio in a Tandem Affinity Microfluidic System," Biomedical Microdevices, 17, 113 (2015).
  • M. Dong, Y. Tian, D. Pappas, "Synthesis of a Red Fluorescent, Dye- Conjugated Ag@SiO2 Nanocomposite for Cell Immunofluorescence," Applied Spectroscopy, 69, 215-221 (2015).
  • H. Somaweera, S. Haputhanthri, A. Ibraguimov, D. Pappas, "On-Chip Gradient Generation in 256 Microfluidic Cell Cultures: Simulation and Experimental Validation" The Analyst, 140, 5029-5038 (2015).
  • Y. Liu, T. Germain, D. Pappas, "Microfluidic Antibody Arrays for Simultaneous Cell Separation and Stimulus," Analytical and Bioanalytical Chemistry 406, 7867-7873 (2014).
  • G. Khanal, S. Hiemstra, D. Pappas, "Probing Hypoxia-Induced Staurosporine Resistance in Prostate Cancer Cells with a Microfluidic Culture System," The Analyst 139, 3274-3280 (2014).
  • M. Dong, Y. Tian, D. Pappas, "Facile Functionalization of Ag@SiO2 Core-Shell Metal Enhanced Fluorescence Nanoparticles for Cell Labeling," Analytical Methods  6, 1598-1602 (2014).
  • H. Somaweera, A. Imbramuov, D. Pappas, "Generation of a Chemical Gradient Across an Array of 256 Cell Cultures in a Single Chip," The Analyst, 138, 5566-5571 (2013).
  • D. Iyer, R.D. Ray, D. Pappas, "High Temporal Resolution Confocal Fluorescence Measurements for Ultrasensitive Detection of Early Stage Apoptosis," The Analyst, 138, 4892-4897 (2013).

Department of Chemistry & Biochemistry