Single-Droplet/cell electrochemistry

biophysical electrochemistry

protein aggregation and condensation

antimicrobial susceptibility

Education

• Ph.D., University of Miami, Coral Gables, FL., 2000
• M.S., Universidad del Valle, Cali, Colombia, 1996
• B.S., Universidad del Tolima, Ibague, Colombia, 1989

Research Interests

Research in our lab focuses on developing electroanalytical methods to address various challenges in biomedical and technological research. Currently, we are investigating individual microbial cells, microdroplets, and other microparticles using stochastic collision electrochemistry. This methodology was recently developed to analyze nano- and microparticles as they collide in real time with microscopic electrodes. Depending on the redox properties of the particle and electrode, collisions generate stochastic and discrete signals from which particle information can be inferred. To elicit the signal, in some cases we use redox reporters that partition inside the particle, or in others, the particle blocks a reporter reacting on the electrode surface. Our long-term goal is to develop measurement procedures that relate the particle electrochemical signal with its size, arrival velocity, and physicochemical processes occurring inside and outside the particle. At present, we aim to discriminate pathological states of microbial cells, as well as disease states in cells and subcellular organelles. Because stochastic collision electrochemistry interrogates individual cells with the possibility of high throughput (i.e. electrode microarrays), this technology has the potential to uncover principles and mechanisms underpinning cellular states and function. 

To complement electroanalytical techniques, researchers in our lab employ other analytical methods along with software tools to model experimental data. In addition to PhD students and postdocs, we are particularly interested in mentoring undergraduate students who wish to pursue graduate careers in chemistry. 

Select Publications

Tubbs, A., Ahmed, J. U., Christhopher, J., Alvarez, J.C., “Savitzky-Golay Processing and Bidemensional Plotting of Current-Time Signals from Stochastic Blocking Electrochemistry to Analyze Mixtures of Rod-Shaped Bacteria,” Anal. Methods, 2024, DOI: 10.1039/D1034AY00899E.

Lutkenhaus, J.A., Ahmed, J.U., Hasan, M., Prosser, D. C., Alvarez, J.C., “Average Collision Velocity of Single Yeast Cells during Electrochemically Induced Impacts”, Analyst, 2024, 149, 3214-3223.

Ahmed, J.U., Lutkenhaus, J.A., Tubbs, A., Nag, A., Christopher, J., and Alvarez, J.C., “Estimating Average Velocities of Particle Arrival Using the Time Duration of the Current Signal in Stochastic Blocking Electrochemistry”, Anal. Chem., 2022, 94, 16560-16569

Ahmed, J.U., Lutkenhaus, J.A., Alam, M.S., Marshall, I., Paul, D.K., Alvarez, J.C., “Dynamics of Collisions and Adsorption in the Stochastic Electrochemistry of Emulsion Microdroplets”, Anal. Chem., 2021, 93, 7993-8001.

Paul, D., Meng, K., Omanovic, D., Alvarez, J.C.; “Hydrogen Bonding and Proton Transfer in Aqueous Toluene Microdroplets Studied by Particle Collision Electrochemistry”, ChemElectroChem, 2018, 5, 2528-2533.

Awards

• National Science Foundation Career Award 2007
• Excellence in Scholarship Award, College of Humanities and Sciences, VCU, 2007
• Outstanding Graduate Student Award, University of Miami, 2000