Capture 1

Innovational of ESSENCE Platform

The significant challenges of an electrochemical sensor for detection and quantification in low-concentration molecular are (1) sensitivity, due to target molecule have high dissociation constant, low electronic field coverage, and double film length; (2) selectivity, due to similar dissociation constants of molecules in the system. These two significant difficulties provide noise and false-positive/negative result that limits the instrument detection limit (IDL). ESSENCE is a novel electrochemical sensing platform that utilizes a shear-enhanced, flow-through, nanoporous, and capacitive electrode technology. Flow-through the electrode enhances the generated shear force, decreasing undesired bonding, and thus preventing non-specific binding and biofouling and contributing to the tunable selectivity of our device. Non-planar interdigitated electrode design providing higher electronic field coverage to the microfluidic system, and is also preventing the electronic signal loss from the fluidic shear, resulting in ultra-sensitivity to the target molecules. Previous work has demonstrated the unparalleled sensitivity of our device for the detection of oligonucleotides, proteins, and Perfluorooctanesulfonic acid (PFOS family).


Point-of-Use PFOS Sensor

The growing global concerns to public health from human exposure to perfluorooctanesulfonate (PFOS) requires rapid, sensitive, in situ detection where current, state-of-the-art techniques are yet to adequately meet sensitivity standards of the real world. A synergistic approach for the targeted affinity-based capture of PFOS using a porous sorbent probe that enhances detection sensitivity by embedding it on a microfluidic platform is developed. This novel sorbent containing platform functions as an electrochemical sensor to directly measure PFOS concentration through a proportional change in electrical current (increase in impedance). The extremely high surface area and pore volume of mesoporous metal−organic framework (MOF) is used as the probe for targeted PFOS capture based on the affinity of the chromium center toward both the fluorine tail groups as well as the sulfonate functionalities. The MOF capture probes are sandwiched between microelectrodes (IDμE) inside a microfluidic channel. The nanoporous geometry, along with interdigitated microelectrodes, increases the signal-to-noise ratio tremendously.

li work

Shear Force Enhanced, Highly Sensitive, Novel Non-planar Interdigitated Microelectrode Detection System for Bio-substrates”

Dopamine (DA) is a catecholamine neurotransmitter widely present in the central nervous system. It influences a variety of motivated behaviors, attention span, and neuronal plasticity and plays a critical role in memory and learning. Altered levels of DA have been implicated in several neurological disorders including Parkinson’s disease and schizophrenia. Monitoring of DA, in the presence of other chemical analogues such as ascorbic acid (AA), uric acid (UA), is crucial in the diagnosis and mechanistic understanding of human neuropathology. Electrochemical transducers are receiving increasingly attention due to its rapid, economical, highly sensitive, and label-free detection characteristics. Therefore, in this project, an non-planar, shear force enhanced, interdigitated microelectrode electrochemical platform (marked as “NP-IDμE”) is applied to selectively detect small bio-substrates (DA, AA, UA). Based on this non-planar platform, more options on the sensing materials (e.g., carbon nanotube (CNT), graphene oxide (GO), Mil-101, Titanium oxide (TiO2)) that with different dielectric constants can be fulfilled and finally applied inside this non-planar device. A series of electrochemical methods (CV, DPV, EIS) will be used to test/study and find the most suitable sensing material for these small bio-substrates. Our final goal is to build a non-planar, shear force enhanced, highly sensitive electrochemical bio-transducer.