Current Research
Non-thermal plasma (NTP) is a partially ionized gas where the electrons are considered thermal, or high energy, while the surrounding gas molecules are at or around room temperature. Our lab specializes in the generation and characterization of these plasmas. We modify our approach to apply plasma based on the chemical makeup of the substrate, e.g. skin, cells, water, plants, etc. The mechanisms behind how plasma components (UV, high electric field, generated reactive species) directly influence these substrates for cancer treatment, wound healing, increase in seed germination, and sterilization are still under investigation. To understand how to optimize plasma treatments for these applications, we measure the transport and delivery of plasma-generated reactive oxygen and nitrogen species in the plasma, gas, liquid and solid phases through spectroscopy (OES, UV-Vis absorption, FTIR, Raman, Electron paramagnetic resonance) and mass spectrometry. We then engineer plasma devices to investigate plasma-liquid interactions, improvements for plasma-based therapy, or enhanced species transfer for plasma-based fertilizer.
Closed-Loop Control System for Plasma Medicine
The Plasma for Life Sciences group has focused on the development of a closed-loop, endpoint detection plasma delivery platform for volume dielectric barrier discharges. Although cold atmospheric pressure plasmas have demonstrated strong therapeutic potential in these systems for wound healing and oncology applications, a standardized clinical plasma dose has not yet been established.
Our approach has integrated real-time electrochemical sensing of reactive oxygen and nitrogen species (RONS) using wire-based biosensors (Ca²⁺, H₂O₂, NO, and ORP) to quantify plasma–tissue biochemical response dynamics. These measurements inform a feedback control architecture in the regulation of plasma output based on biologically relevant endpoints.
The platform has been evaluated across in vitro (HaCaT cells), in vivo (mouse and rabbit models), and in ex vivo fungal infection systems through collaborations with Drexel University, Rutgers University, and the NC State College of Veterinary Medicine. Current efforts are expanding toward determining treatment safety thresholds, identifying healing-optimized RONS profiles, and advancing toward clinical translation. Our long-term goal is to develop clinically deployable plasma therapies equipped with real-time feedback and dosing control to improve healing outcomes.
This project is supported by NIH Grant R01EB029705
Researchers: Jonathan Thomas, Kristina Pattison, Jason Rainone, Jordan Simpson,
Noah Gobel
Plasma-treated Water for Agriculture
At the core of species transport from the plasma phase through the liquid phase is the interaction between the plasma-liquid interface. Rate of change of the pH, conductivity, and chemical species solvated in the liquid phase are dependent on the surface area to volume ratio between the plasma and liquid phase. Supplying adequate nitrogen is essential for plant fertilization. Different reactive nitrogen & oxygen species (RONS) are also important signaling species for the health and growth of the plant.
Our lab is investigating several plasma devices to characterize both the species content and concentrations, as well as energy efficiencies to aid in on-demand Plasma Treated Water (PTW) fertilizer for greener means to crop-tailored agriculture. Plasma effluent transported through bubbles, as well as direct plasma breakdown in bubbles, are utilized to increase the surface-area-to-volume ratio of the gas/liquid interface at which RONS transport occurs.
This research is carried out in collaboration with the interdisciplinary research team funded by the Game-Changing Research Incentive Programs for the Plant Science Initiative (GRIP4PSI) here at NCSU.
Researchers: Conner Robinson
Non-Oxidative Plasma-Driven Mechanisms for PFAS Destruction
Per- and polyfluoroalkyl substances (PFAS) are a class of man-made chemicals commonly found as harmful contaminants in groundwater. PFAS have been linked to a wide array of health effects in both humans and animals including liver damage, thyroid disease and cancer. These compounds are characterized by strong carbon-fluorine bonds and are very hard to break down via traditional water treatment methods. This project seeks to expand upon previous work that has shown plasma treatment as an effective technique for aqueous PFAS destruction. We investigate the reaction pathways of non-oxidative species produced in the gas phase of an RF atmospheric pressure plasma jet (APPJ) as these species are theorized to dominate PFAS breakdown.
Additionally, a COST-Jet is employed to examine the impact of photons and other uncharged particles on non-oxidative chemistry in a liquid substrate. Particular attention is paid to the production of ions, metastable atoms, and photons. Analysis is predominantly carried out using optical emission spectroscopy (OES) and ICCD imaging. These measurements are supplemented using different modeling approaches to predict fluxes of photons and reactive species to the treatment substrates.
This work is conducted in collaboration with Dr. Selma Mededovic’s group at Clarkson University and Dr. Arthur Dogariu’s group at Texas A&M University. The research is supported by the National Science Foundation under NSF grant PHY 2308857.
Researchers: Caleb Smith, Micheal Ojo, María J. Herrera Quesada
Generation and Transport of Reactive Species for Plasma Medicine
NTP treatment has been shown to be effective for chronic wounds, cancer, and even antibiotic-resistant bacterial infections. Although the positive effects of NTPs are well documented, the underlying chemical and biological mechanisms are still not well understood due to the inherent complexity of plasma components (electric fields, UV radiation, and reactive chemical species) and their effects on biological substrates. Among the myriad reactive species that are produced in NTPs, we investigate biologically relevant RONS (e.g. OH, H2O2, NO..) produced by the NTP source COST-Jet (European Center of Science and Technology atmospheric pressure plasma jet) on substrates such as amino acids, enzymes, cell media, and cells.
Current experimental diagnostic techniques include FTIR (Fourier Transform Infrared) Spectroscopy, Mass Spectrometry, Raman Spectroscopy, Photometric Assays, and EPR (Electron Paramagnetic Resonance) Spectroscopy, and LIF (Laser Induced Fluorescence). These studies will help us find efficient plasma source parameters for RONS transport and ultimately help tailor plasma sources used for medicine.
This work has been funded by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences Opportunities in Frontier Plasma Science program under Award Number DE-SC-0021329, the UNC Lineberger Cancer Center, and NIH project R01EB029705.
Researchers: María J. Herrera Quesada
Surface Modification of Plasma-Treated Human Surrogate Skin
The implementation of plasma therapy is limited due to insufficient information for establishing a correct ‘dose’. To understand how to select a suited ‘dose’, we focus on answering two major elements: 1) the physical penetration depth of plasma components, and 2) the penetration depth of the plasma-induced effects. Using 3-dimensional Raman spectroscopy, we identify modifications in plasma-treated human surrogate skin to track the physical depth of penetration and radial distribution of plasma-generated RONS for given discharge parameters.
Researchers: María J. Herrera Quesada