Insulator-based dielectrophoretic (iDEP) trapping, separating, and concentrating nanoscale objects is carried out using a non-metal, unbiased, mobile tip acing as a tweezers. The spatial control and manipulation of fluorescently-labeled polystyrene particles and DNA were performed to demonstrate the feasibility of the iDEP tweezers. Frequency-dependent iDEP tweezers' strength and polarity were quantitatively determined using two theoretical approaches to DNA, which resulted in a factor of 2 ~ 40 differences between them. In either approach, the strength of iDEP was at least 4-order of magnitude stronger than the thermal force, indicating iDEP was a dominant force for trapping, holding, and separating DNA. The trapping strength and volume of the iDEP tweezers were also determined, which further supports direct capture and manipulation of DNA at the tip end.

Recent developments in chimeric antigen receptor (CAR) T-cell therapy for cancer have shown promising results. CAR T-cells are engineered mainly by AC or DC electroporation to express CAR molecules on their surfaces. Electroporation has detrimental effects on the majority of T-cells and causes cell death via apoptosis or necrosis. These non-viable cells have potentially harmful effects on other healthy T-cells. Because there are no unique biomarkers that pinpoint the apoptosis and necrosis of T-cells, currently available cell separation methods are incapable of purifying healthy T-cells after electroporation. To address this critical issue, we have used dielectrophoretic cell isolation in a simple microfluidics chip. Our results indicate that it is possible to purify cell samples after electroporation and achieve ~100% purity and >90% target cell recovery. Therefore, this work presents a viable solution to a critical need in CAR T-cell manufacturing.

There is a growing interest for viral vector-free chimeric antigen receptor (CAR) T-cells due to its ability to kill cancer cells without adverse side effects. A potential avenue for manufacturing...

The detection and quantification of nucleic acid and proteomic biomarkers in bodily fluids is a critical part of many medical screening and diagnoses. However, majority of the current detection platforms are not ideal for routine, rapid, and low-cost testing in point-of-care settings. To address this issue, we developed a concept for a disposable universal point-of-care biosensor that can detect and quantify nucleic acid and proteomic biomarkers in diluted serum samples. The central tenet of sensing is the use of dielectrophoresis, electrothermal effects, and thermophoresis to selectively and rapidly isolate the biomarkers of interest in electrodes and then quantify using electrical impedance. When the sensor was applied to quantify microRNA and antigen biomarker molecules directly in diluted serum samples, it produced a LOD values in the fM range and sensitivity values from 10 12 to 10 15 /M with a 30 min assay time and assay cost of less than $50 per assay.

Electrical impedance based biosensing is a label‐free technique that is gaining momentum in biology/medicine. The electrical impedance, typically measured using an array of micro‐fabricated interdigitated electrode array (IDE), is a byproduct of the interaction between electric fields and target bio‐molecules/cells. In current impedance based biosensing, it has been focused on utilizing the magnitude of the impedance (|Z|) to detect/quantify bio‐molecules. There were no reports on designing IDE electrodes, sensitivity analysis and detailed impedance data analysis. To address this issue, we have designed and fabricated IDE array and performed model experiments. We have found that depending on the frequency of the external electric potential, there is a variation of electric field across the array of IDEs from first pair to last pair. We then developed impedance data analysis technique (using (|Z|) and its phase (φ)) to analyze the complex impedance data, and finally, we have utilized Warburg theoretical circuit model to calculate the capacitance and resistance of the individual IDE pairs in the constant phase impedance region. Using the capacitance values, we have developed a procedure to determine the sensitivity of the IDE array. We have found that sensitivity of the IDE array does not depend on the sample conductivity.