Development and application of a wearable device for real time potentiometric determination of electrolytes in sweat

The most common methods of biomedical diagnosis are blood-based and therefore require invasive methods for acquiring a sample causing trauma and presenting a risk of infection. This has led to the development of sensors targeting minimally invasive bio-fluids such as interstitial fluid and non-invasive bio-fluids including saliva and sweat. The monitoring of sweat in electrolytes, for example, has a number of applications including determining the efficacy of drugs on the chloride and sodium levels in cystic fibrosis patients as well as the monitoring of hydration levels in athletes to detect non-symptomatic overhydration, dehydration and fatigue. This work presents the development of a platform for harvesting and analysing the sodium content of sweat in real time. In chapter 2 miniaturised solid-state sodium-selective and reference electrodes are developed, characterized and optimised. In chapter 3 these sensors are then incorporated into a custom designed sampling and fluidic system allowing passive transfer of the sweat from a point of contact on the skin to a fluidic channel across the electrodes for analysis before transport to a sampling reservoir. Chapter 4 presents the integration and real-time on-body trials of the sensing and fluidic components with a custom-designed electronic circuit board and lithium battery. Two platforms were developed, a ‘watch’ type format for wrist based analysis and a ‘pod’ format, arranged horizontally for adaptable monitoring in various regions of the body. The devices can be easily disassembled to replace the electrodes and the high capacity adsorbent material. The storage sweat is available for subsequent measurement of the total volume of sweat harvested and the average concentration of sodium over the period of use. Results obtained during trials over a period of up to 60 minutes controlled exercise are consistent with previously published data, showing a gradual increase of the sodium concentration in the sweat during this period

Reusable Ionogel-based Photo-actuators in a Lab-on-a-disc

This paper describes the design, fabrication and performance of a reusable ionogel-based photo-actuator, in-situ photopolymerised into a lab-on-a-disc microfluidic device, for flow control. The ionogel provides an effective barrier to liquids during storage of reagents and spinning of the disc. A simple LED (white light) triggers actuation of the ionogel for selective and precise channel opening at a desired location and time. The mechanism of actuation is reversible, and regeneration of the actuator is possible with an acid chloride solution. In order to achieve regeneration, the Lab-on-a-Disc device was designed with a microchannel connected perpendicularly to the bottom of the ionogel actuator (regeneration channel). This configuration allows the acid solution to reach the actuator, independently from the main channel, which initiates ionogel swelling and main channel closure, and thereby enables reusability of the whole device.Economía y Competitividad), Spain. This project has receivedfunding from the European Union Seventh Framework Programme(FP7) for Research, Technological Development and Demonstrationunder grant agreement no. 604241. JS and FBL acknowledge fund-ing support from Gobierno de Espa˜na, Ministerio de Economía yCompetitividad, with Grant No. BIO2016-80417-P and personallyacknowledge to Marian M. De Pancorbo for letting them to use herlaboratory facilities at UPV/EHU. A.T., L.F., and D.D. are grateful forfinancial support from the Marie Curie Innovative Training Net-work OrgBIO (Marie Curie ITN, GA607896) and Science FoundationIreland (SFI) under the Insight Centre for Data Analytics initiative,Grant Number SFI/12/RC/2289

Visuo-attentional correlates of Autism Spectrum Disorder (ASD) in children with Down syndrome: A comparative study with children with idiopathic ASD.

BACKGROUND: Children with Down syndrome (DS) are at increased likelihood of Autism Spectrum Disorder (ASD) relative to the general population. To better understand the nature of this comorbidity, we examined the visuo-attentional processes associated with autistic trait expression in children with DS, focusing specifically on attentional disengagement and visual search performance. METHOD: We collected eye-tracking data from children with DS (n = 15) and children with idiopathic ASD (iASD, n = 16) matched according to chronological age. Seven children with DS had a formal clinical diagnosis of ASD (DS+ASD). RESULTS: In children with iASD, but not DS, higher autistic trait levels were associated with decreased temporal facilitation on a gap-overlap task, implying increased visuospatial orienting efficiency. In all cases, higher autistic trait levels were associated with improved visual search performance according to decreased target detection latency. On a visual search task, children with DS+ASD outperformed their peers with DS-ASD, mirroring the phenotypic advantage associated with iASD. We found no evidence of a relationship between attentional disengagement and visual search performance, providing preliminary evidence of a differentiation in terms of underlying visuo-attentional mechanism. CONCLUSION: We illustrate the value of progressing beyond insensitive behavioural measures of phenotypic description to examine, in a more fine-grained way, the attentional features associated with ASD comorbidity in children with DS

Xurography actuated valving for arbitrary timing of centrifugal flow control in parallelized multi-step bioassays

Here we introduce a new, instrument controlled valving scheme for the centrifugal platform which is based upon dissolvable film (DF) technology. Liquid, restrained at any point upon the disc, is prevented from wetting a DF via a trapped gas pocket. From this pocket a pneumatic channel runs to a sealed vent located on the top surface of the disc. Controlled scouring of this seal by a robotic knifecutter permits venting of the trapped gas, and thus actuation of the valve. To demonstrate the potential of these valves, we present a disc developed towards a biplex liver assay panel

A portable centrifugal analyser for liver function screening

Mortality rates of up to 50% have been reported after liver failure due to drug-induced hepatotoxicity and certain viral infections(Gao et al. 2008). These adverse conditions frequently affect HIV and tuberculosis patients on regular medication in resource-poor settings. Here, we report full integration of sample preparation with read-out of a 5-parameter liver assay panel (LAP) on a portable, easy-to-use, fast and cost- efficient centrifugal microfluidic analysis system (CMAS). Our unique, dissolvable-film based centrifugo- pneumatic valving was employed to provide sample-to-answer fashion automation for plasma extraction (from finger-prick of blood), metering and aliquoting into separate reaction chambers for parallelized colorimetric quantification during rotation. The entire LAP completes in less than 20 minutes while using only a tenth the reagent volumes when compared with standard hospital laboratory tests. Accuracy of in-situ liver function screening was validated by 96 separate tests with an average coefficient of variance (CV) of 7.9% compared to benchtop and hospital lab tests. Unpaired two sample statistical t-tests were used to compare the means of CMAS and benchtop reader, on one hand; and CMAS and hospital tests on the other. The results demonstrate no statistical difference between the respective means with 94% and 92% certainty of equivalence, respectively. The portable platform thus saves significant time, labour and costs compared to established technologies, and therefore comply with typical restrictions on lab infrastructure, maintenance, operator skill and costs prevalent in many field clinics of the developing world. It has been successfully deployed in a centralised lab in Nigeria

Baker Center Journal of Applied Public Policy - Vol. IV, No. I

This is the 4th volume of the Baker Center Journal on Applied Public Policy. It includes articles on nuclear nonproliferation, American political development, election issues, Tennessee state trial courts, attitudes related to rich and poor people, and two student articles on science, innovation, technology and economic growth and explosive trace detection at airports

Application of programmable bio-nano-chip system for the quantitative detection of drugs of abuse in oral fluids

Objective: There is currently a gap in on-site drug of abuse monitoring. Current detection methods involve invasive sampling of blood and urine specimens, or collection of oral fluid, followed by qualitative screening tests using immunochromatographic cartridges. While remote laboratories then may provide confirmation and quantitative assessment of a presumptive positive, this instrumentation is expensive and decoupled from the initial sampling making the current drug-screening program inefficient and costly. The authors applied a noninvasive oral fluid sampling approach integrated with the in-development chip-based Programmable bio-nano-chip (p-BNC) platform for the detection of drugs of abuse. Method: The p-BNC assay methodology was applied for the detection of tetrahydrocannabinol, morphine, amphetamine, methamphetamine, cocaine, methadone and benzodiazepines, initially using spiked buffered samples and, ultimately, using oral fluid specimen collected from consented volunteers. Results: Rapid (∼10 min), sensitive detection (∼ng/mL) and quantitation of 12 drugs of abuse was demonstrated on the p-BNC platform. Furthermore, the system provided visibility to time-course of select drug and metabolite profiles in oral fluids; for the drug cocaine, three regions of slope were observed that, when combined with concentration measurements from this and prior impairment studies, information about cocaine-induced impairment may be revealed. Conclusions: This chip-based p-BNC detection modality has significant potential to be used in the future by law enforcement officers for roadside drug testing and to serve a variety of other settings, including outpatient and inpatient drug rehabilitation centers, emergency rooms, prisons, schools, and in the workplace

Development of a sensitive, low-cost and user-friendly centrifugal microfluidic cartridge for multi-analyte environmental monitoring

This paper describes the development of a simple centrifugal cartridge for the analysis of nitrite, ammonia and phosphate from a water sample. The cartridge is operated in combination with the Centrifugal Microfluidic Analysis System (CMAS)[1] which incorporates rotational control with optical and communication components for portable analysis of environmental and biomedical samples[1,2]. An LED and a photodiode allow colorimetric determination of specific analytes depending on which reagent-based analytical method is employed. Bluetooth wireless communications provides automatic uploading of analytical data to cloud-based information systems. Microfluidic discs consisting of three PMMA (Poly(methyl methacrylate)) layers bonded together by two PSA (Pressure Sensitive Adhesive) layers were prepared. The sample was transported from a single chamber to three aliquoting chambers at a low rotational frequency prior to the actuation of dissolvable film valves[3] at an increased rotational frequency to facilitate sample transport to reaction/detection chambers. Ammonia standards were analysed using a modified Berthelot method, the stannous chloride method was used to detect orthophosphate levels while a diazotization method was employed to determine nitrite concentration. Photodiode analysis on the CMAS platform obtained LOD’s of 0.233 ppm for ammonia and 0.189 ppm for orthophosphate and 50 ppb for nitrite

‘SWEATCH’ – A platform for real-time monitoring of sweat electrolyte composition

Since the initial breakthroughs in the 1960’s and 70’s that led to the development of the glucose biosensor, the oxygen electrode, ion-selective electrodes, and electrochemical/optochemical diagnostic devices, the vision of very reliable, affordable chemical sensors and bio-sensors capable of functioning autonomously for long periods of time (years), and providing access to continuous streams of real-time data remains unrealized. This is despite massive investment in research and the publication of many thousands of papers in the literature. It is over 40 years since the first papers proposing the concept of the artificial pancreas, by combining the glucose electrode with an insulin pump. Yet even now, there is no chemical sensor/biosensor that can function reliably inside the body for more than a few days, and such is the gap in what can be delivered (days), and what is required (minimum 10 years) for implantable devices, it is not surprising that in health diagnostics, the overwhelmingly dominant paradigm for reliable measurements is single use disposable sensors. Realising disruptive improvements in chem/bio-sensing platforms capable of long-term (months, years) independent operation requires a step-back and rethinking of strategies, and considering solutions suggested by nature, rather than incremental improvements in available technologies