Research Description
The SEEDS biosensor lab, headed by Prof. Jeffrey M. Halpern, focuses on surface modifications towards the recruitment of biomolecules towards an electrochemical sensor surface for enhanced sensitivity and selectivity. We are actively involved with various detection paradigms, primarily using electrochemical analytical methods to evaluate biological media. Our group mainly focuses on analyzing ex vivo biosamples (blood, saliva, etc. removed from the body. i.e. blood draw); we hope to accurately identify and diagnose various diseases early and accurately from these biosamples.
Our laboratory is currently involved with two main projects.
Developing a Cyclodextrin-Based Cross-Reactive Electrochemical Sensor Towards Disease Diagnosis
Diseases can often lead to changes in metabolites in a patients blood. Specifically, hydrophobic metabolites, such as cholesterols, acylcarnitines, and glycerolphospholipids are gaining particular attention. Currently, the primary methods to analyze multiple metabolites in biofluids are high performance liquid chromatography-mass spectroscopy or nuclear magnetic resonance. These primary methods require expensive equipment, long sampling and analysis times, and high maintenance costs, which limit their use in research and clinical settings. Further, hydrophobic analytes can be difficult to detect electrochemically in a complex solution, especially in aqueous and biofluid solutions. In aqueous solutions, hydrophobic molecules are in small concentrations and often not electrochemically active (e.g., cholesterol and cortisol) or are only weakly electrochemically active (e.g., acylcarnitines).
Molecular recognition sensor surfaces that are designed for hydrophobic molecules can improve sensitivity by recruiting hydrophobic bioanalytes to the sensor surface. An increase in sensitivity (25-100 fold) have been observed in measuring lipids and other hydrophobic molecules with chemically modified electrodes. Cyclodextrin (CD) has been previously used to enhance the electrochemical signal of bioanalytes and hydrophobic molecules; however, previously developed of CD-sensors were for single-use applications and were evaluated in simple solutions without competing complexing agents. Analysis of repeatability (i.e., reusability) of the sensor is rarely tested because it is difficult to remove the analyte from the CD pocket after a complex forms. We propose to use CD as a way to reproducibly detect weakly electrochemically active and non-electrochemically active hydrophobic species towards diagnosis.
The overall objective of this work is to develop a robust molecular recognition electrochemical technique to diagnose diseases via cross-reactive sensing platform. In selective sensing, each sensor surface measures a single chemical in solution through traditional biorecognition element strategies. Cross-reactive sensing, a completely different sensing paradigm, is a signature-based profiling technique, simultaneously monitors multiple biomarkers. The sensor surfaces are modified to interact with certain families of analytes. Cross-reactive sensing is a powerful strategy for disease diagnosis by identifying a diagnostic fingerprint, and the sensor array is trained for a chemical profile associated with a disease. An array of multiple sensors, each with a different surface modification, is necessary to accurate correlate to differences in samples. The raw data from each sensor is analyzed and converted to conical axes. From this information, we should be able to see differences in the family of analytes towards the identification of metabolomics changes in biofluid samples.
Research team includes:
Ferdows Sajedi
Julia Edgar
Sydney Crotteau
Previously funded by an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health, an NIH P20 program P20GM113131, NSF EPSCoR award #1757371, and NH INBRE P20GM103506.
Elastin-Like Polymer for Selective Biomarker Identification
In collaboration with Eva Rose Balog, Department of Chemistry and Physics, University of New England, we are working on developing a novel selective biosensor. Elastin-like polymer (ELP) is known for its reverse lower critical solution temperature (LCST), and that it will dissolve at low temperatures, ionic strength, and lack of other stimuli. Upon increasing the temperature, ELP will collapse and coalesce to precipitate out of the solution. Most researchers study ELP in solution, looking at the 3D properties of this polymer for drug delivery and solubility applications. We propose to look at the stimuli response of surface bound ELP. Further, we are investigating the ability to selectively recruit and capture (or release) specific biomarkers for diagnostic purposes. We will be qualifying these experiments with our 3T-Analytik electrochemical quartz crystal microbalance with dissipation (eQCM-D) (http://3t-analytik.de/products/qcm-d-instruments/qcell-t-series) and electrochemical impedance spectroscopy.
Research team includes:
Katarina Jovic
Stanley Feeney
Sarah Bramlitt-Harris
Zahraa Albeshir
Henry Roell
Laurel Nelson
Grace Higgins
Isabelle Hu
Ryan Brown
Corinne Fernald
Current funding: NSF EPSCoR award #2119237
Previously funded through the NSF EAGER program 163896.
Collaborators: Eva Rose Balog, (http://blog.une.edu/baloglab/)
Caleb Hill: (https://www.the-hill-lab.com/)
Robert Pantazes: (https://eng.auburn.edu/directory/rjp0029)