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Potentiostats are one of the fundamental instruments used to study electrochemical reactions as they enable researchers to delve deeper into reaction mechanisms and electron kinetics between redox species of interest. Because multi-channel potentiostats are often costly investments, this work discusses the plausibility of self-developing more affordable single-channel potentiostats as an efficacious alternative option. In this work, I discuss the process and results of self-programming multi-channel capabilities onto software designed for a single-channel potentiostat (Emstat3 from PalmSens BV�) using the manufacturer-provided software development kit with MATLAB� programming. Successful implementation of the multi-channel functionality was demonstrated within this work as up to four connected potentiostats were able to run separate, real-time measurements on different experimental systems simultaneously. Obtained data from 50 uM and 500 uM concentrations of Zobell’s solution electrochemical cells, a dummy cell, and an insulated resistor using the self-developed software on MATLAB is reported. Within this work, the linear sweep voltammetry (LSV), cyclic voltammetry (CV), single-step chronoamperometry (CA), and open circuit potentiometry (OCP) functions of the potentiostat were experimented with. Furthermore, the acquired data was then compared to that from a larger, more expensive potentiostat alternative (Gamry Instruments Interface 1010B) to gauge its accuracy and validity.

With rapid technological progress, electrochemical methods are being developed and improved throughout the years. Outdated models of electrochemical equipment like potentiostats are replaced with newer models with more functions and capability. Since those outdated models are programmed using programming language like C++, users can utilize the source code to program new features to the outdated potentiostats, extending its period of use. We developed methods enabling users to create new functionality of an electrochemical analytical system using its software development platform on MATLAB� to perform complex voltammetric measurements and self-adjustable electrolysis. Complex voltammetric measurement is defined by running chronoamperometry under arbitrary potential waveform rather than the traditional constant voltage chronoamperometry or triangular potential waveform used in cyclic voltammetry. Self-adjustable electrolysis is demonstrated as a proof-of-concept via a nanowire array electrode, monitoring, and self-adjusting potentiostat parameters throughout the experiment with the execution of a control loop. The development of arbitrary waveform allows the potential improvement of sensitivity in electroanalytical methods for detecting compounds and their redox potential, whereas the development of self-adjustable electrolysis facilitates in the self-optimization of method parameters in electrochemical measurement through a control loop mechanism.

There is a growing need for accurate, wearable electrochemical sensors for use in a large range of industries including medical, fitness, military, environmental and food. The wearable medical device market has traditionally been dominated by activity trackers [1]; however, the conclusion of the Apple Heart Study and subsequent FDA approval of a watch based electrocardiogram shows the expansion of the wearable medical device market [2]. This work presents a generalized set of guidelines that can be followed to design wearable electrochemical sensing systems at a high technology readiness level. Specific emphasis is placed on the engineering tradeoffs involved in the design of the electronics and the sensing of biomedically important analytes. These guidelines are used as a blueprint in the development of a minimally invasive continuous glucose monitor. This system is tested and analyzed to confirm that it is operating as intended. The continued development and widespread adoption of wearable electrochemical sensors has the potential to provide a wealth of bioanalytical information which could have a tremendous impact on healthcare systems.

The occurrence of pediatric septic shock is a major health concern in the United States.Children are often susceptible to contract sepsis due to microbial invasion, and there have been42,000 cases of septic shock annually with an approximate 10% mortality rate [1]. Pediatricpatients going through septic shock often exhibit critically low levels of zinc (Zn), which is animportant trace element required for normal functioning of hormones, certain enzymes, andtranscription-related factors [2]. Thus, it has been proposed to use oral supplementation of Zn asa therapeutic strategy to treat critically ill patients [3]. In order to protect patients, it is necessaryto closely monitor Zn concentration levels in blood serum due to the risk of heavy metal toxicity.If Zn concentration levels are not maintained near physiologically normal levels, heavy metaltoxicity can cause major problems for the patient and malpractice concerns for the doctor.Current methods of monitoring Zn concentration involve taking a blood sample andsending it to an external laboratory for processing. The two primary methods for measuring Znconcentration are Atomic Absorption Spectroscopy (AAS) and Inductively Coupled MassSpectroscopy (ICP-MS), which have turnaround times ranging from a few hours to a few days.This timeframe is inadequate for monitoring patients undergoing oral Zn supplementation, as itwould be too late to take counter-measures to reverse over-supplementation by the time resultsare received from the external laboratory.The limitations of current measurement methods have impeded the use of oral zincsupplementation in clinical experiments that could save many lives. This impetus has promptedthe development of a device for measuring Zn concentration in blood serum in a rapid manner. APoint-of-Care (POC) device to overcome these obstacles has been in the works by students at theiiUniversity of Cincinnati for several years. The device involves a three electrode sensor (oftenreferred to as the Zinc Chip) and an embedded system (often referred to as the Zinc Chip Reader)to facilitate and process concentration measurements. The complete system is able to takemeasurements on a blood serum sample in approximately six minutes – drastically less time thancurrent methods being used.This thesis reports on the third generation device, which builds upon the work of twoprevious students to create a device that can be easily packaged and used in a POC setting. Thethird generation device is contained in a single Printed Circuit Board (PCB), which removes thecommercial development boards that were used in the two prior generations. This will make for asmooth transition into a clean and aesthetically pleasing package that will be easily incorporatedinto the clinical setting. Additionally, the third generation device has moved to a new, morepowerful microcontroller family that is able to automatically quantify Zn concentration. This isin contrast to the previous generation devices, which required an external computer with aSecure Digital (SD) memory Card reader for processing. The new design results in majorbenefits in terms of size, weight, portability, cost, and functionality.This thesis reports on the design and functional demonstration of the third generationZinc Chip Reader.

Implantable micro- and nano- sensors and implantable microdevices (IMDs) have demonstrated potential for monitoring various physiological parameters such as glucose, lactate, CO2 [carbon dioxide], pH, etc. Potentiostats are essential components of electrochemical sensors such as glucose monitoring devices for diabetic patients. Diabetes is a metabolic disorder associated with insufficient production or inefficient utilization of insulin. The most important role of this enzyme is to regulate the metabolic breakdown of glucose generating the necessary energy for human activities. Diabetic patients typically monitor their blood glucose levels by pricking a fingertip with a lancing device and applying the blood to a glucose meter. This painful process may need to be repeated once before each meal and once 1- 4 hour after meal. Patients may need to inject insulin manually to keep the blood glucose level at 3.9-6.7 mmol [mili mol] /liter. Frequent glucose measurement can help reduce the long term complication of this disease which includes kidney disease, nerve damage, heart and blood vessel diseases, gum disease, glaucoma and etc. Having an implanted close loop insulin delivery system can help increase the frequency of glucose measurement and the accuracy of insulin injection. The implanted close loop system consists of three main blocks: (1) an electrochemical sensor in conjunction with a potentiostat to measure the blood glucose level, (2) a control block that defines the level of insulin injection and (3) an implanted insulin pump. To provide a continuous health-care monitoring the implantable unit has to be powered up using wireless techniques. Minimizing the power consumption associated with the implantable system can improve the battery life times or minimize the power transfer through the human body. The focus of this work is on the design of low-power potentiostats for the implantable glucose monitoring system. This work addresses the conventional structures in potentiostat design and the problems associated with these designs. Based on this discussion a modification is made to improve the stability without increasing the complexity of the system. The proposed design adopts a subthreshold biasing scheme for the design of a highly-stabilized, low-power potentiostats.

A novel miniaturized amperometric analyzer with enhanced performance was developed to meet the need of field-portable, wide adaptable, user friendly, and cost effective electrochemical detection in various application fields. Based on the new MSP430FG479 microcontroller, the embedded system was designed to either operate as a stand-alone unit with an on-board fool-proof user interface, or run on the user's PC for advanced data analysis. Amperometric detection is a powerful experimental approach for the study of electro-active compounds with clinical, industrial, environmental and agricultural importance. Inside the amperometric analyzer, a mini-potentiostat is designed to interface with a wide spectrum of electrochemical sensors. Implemented with grounded-auxillary electrode configuration, the mini-potentiostat controls oxidationreduction reactions of target analytes at the working electrode surface by accurately maintaining a preset potential between the working (WE) and the reference electrode (RE), while measuring the redox current response at the auxillary electrode (AE) using a low-side resistive sensing mechanism. In an unstirred solution, at steady state, the rate of electron transfer is directly proportional to the concentration of the reactant. Therefore, the steady state current is used as an accurate measure of the analyte concentration in the sample. Constructed using off-the-shelf IC chips and powered by a single 3V lithium coin cell battery, the potentiostat circuitry inside the amperometric analyzer is designed to meet potential control and current detection requirements for most existing electrochemical sensors. Featured with sub-picoampere sensitive, wide span and high accuracy current sensing, the specially designed current sensing block not only covers general application requirements, but it can also serve as a powerful tool in research efforts toward the next generation of ultra-sensitive detection systems in biomolecular sensing. In addition to the superior electrochemical related specifications, various lowpower design techniques have been applied to ensure a prolonged battery life, therefore making the system an ideal platform for amperometric monitoring in field appropriate applications. Confirmed with a systematic evaluation of the device prototype, the system features a 4-month battery life with a single 3V lithium battery (220mAh), accurate bidirectional redox potential control from -1.2V to +1.2V, high resolution current detection from ±5pA to ±1mA covered by 4 software selectable detection levels, improved stability unaffected by electrochemical sensor impedance, and high EMI immunity without external shielding. Finally, electrochemical analyses were also conducted using the device prototype. For a constant potential amperometric experiment, the experimental results of the system were compared with a standard bench top electrochemical workstation (the BAS Epsilon). Excellent agreement was attained over the whole detection range, which demonstrates the excellent potential control and current sensing abilities of the amperometric analyzer.

With rapid advancements in micro fluidics making it an extremely important section in the field of biological and bioelectronics research, the availability of suitable MEMS components for micro fluidic applications has become important. Such components include micro valves, micro pumps, micro flow sensors and bio filters. In the past few years, a large number of microfluidic prototype devices and systems have been developed at the University of Cincinnati with these components. Microfluidic systems for warfare detection systems have also been developed from commercial components. All these microfluidic systems use the principle of sandwich immunoassay to detect microorganisms in liquid samples.With the development of these systems, there arises a need for specialized detection schemes. Such a detection system was developed and tested with microfluidic components. The detection scheme emphasizes a low threshold and noise. A potentiostat board was developed and tested for the same purpose. Tests were done underntiostat. After the circuit was tested fully, it was designed into an analog ASIC for which circuits were developed. The ASIC was simulated using relevant environmental and design information and the results presented.