Low-Cost Quantitative Photothermal Genetic Detection of Pathogens on a Paper Hybrid Device Using a Thermometer.

Tuberculosis (TB), one of the deadliest infectious diseases, is caused by Mycobacterium tuberculosis (MTB) and remains a public health problem nowadays. Conventional MTB DNA detection methods require sophisticated infrastructure and well-trained personnel, which leads to increasing complexity and high cost for diagnostics and limits their wide accessibility in low-resource settings. To address these issues, we have developed a low-cost photothermal biosensing method for the quantitative genetic detection of pathogens such as MTB DNA on a paper hybrid device using a thermometer. First, DNA capture probes were simply immobilized on paper through a one-step surface modification process. After DNA sandwich hybridization, oligonucleotide-functionalized gold nanoparticles (AuNPs) were introduced on paper and then catalyzed the oxidation reaction of 3,3',5,5'-tetramethylbenzidine (TMB). The produced oxidized TMB, acting as a strong photothermal agent, was used for the photothermal biosensing of MTB DNA under 808 nm laser irradiation. Under optimal conditions, the on-chip quantitative detection of the target DNA was readily achieved using an inexpensive thermometer as a signal recorder. This method does not require any expensive analytical instrumentation but can achieve higher sensitivity and there are no color interference issues, compared to conventional colorimetric methods. The method was further validated by detecting genomic DNA with high specificity. To the best of our knowledge, this is the first photothermal biosensing strategy for quantitative nucleic acid analysis on microfluidics using a thermometer, which brings fresh inspirations on the development of simple, low-cost, and miniaturized photothermal diagnostic platforms for quantitative detection of a variety of diseases at the point of care.

Tympanic Membrane Temperature and Hemispheric Cognitive Style.

The authors tested the hypothesis that there is a correlation between hemispheric cognitive style and ear temperature. A sample of 100 participants completed a measure of hemispheric cognitive style, the Hemispheric Consensus Prediction Profile. Ear temperatures were taken in 2 sessions, 2 times for each ear at each session. Average left ear temperature was subtracted from average right ear temperature as an index of dominant temperature. Only 56 of the participants showed a stable dominant ear temperature. For these 56 participants, there was a statistically significant positive correlation between scores on the Hemispheric Consensus Prediction Profile and tympanic member temperature (Spearman's  ρ =.29, 95% CI [.04,.51]). Individuals with a left hemispheric cognitive style tended to have a warmer left tympanic membrane temperature while those with a right hemispheric cognitive style tended to have a warmer right tympanic membrane temperature. Tympanic membrane temperatures are easily obtained using inexpensive and noninvasive technology. The relationship suggested by these findings may open new opportunities for the study of cerebral asymmetry.

Cost minimisation analysis of thermometry in two different hospital systems.

INTRODUCTION: Temperature monitoring can be accomplished by various methods, including oral (OT), rectal (RT), axillary (AT), tympanic membrane (TMT) and temporal artery (TAT) thermometry, with varying amounts of cost incurred by healthcare systems. METHODS: The potential thermometry cost savings in two hospital systems-University Hospital Centre Zagreb (UHCZ), which uses TMT (device Covidien Genius 2) and University of Michigan Hospitals (UMH), which relies on OT, RT and AT (device Welch Allyn suretemp plus 692)-were analysed to evaluate institution-wide TAT (device Exergen TAT-5000) implementation. Two scenarios were developed: scenario 1, comparing costs for a period of 1, 3 and 5 years; scenario 2, calculation of the number of measurements per device for TAT to be cost-effective. RESULTS: At UHCZ, use of TAT would bring budget savings regardless of the number of devices per bed and the number of years observed. Savings would range from US$0.08 million (one device per bed, impact for 1 year) to US$1.8 million (one device per 10 beds, impact for 5 years). At UMH, use of TAT would lead to budget savings if one device per 10 beds were acquired, but only over a period of 3 or 5 years. Other TAT scenarios were associated with budget costs at UMH even after a period of 5 years. CONCLUSIONS: Sensitivity analyses showed that the price of current consumables had the highest impact on the model in both hospital settings, with TAT up to 10 times cheaper in that regard over TMT at UHCZ, potentially leading to considerable budget savings within a year of hospital-wide implementation.

A Lab Assembled Microcontroller-Based Sensor Module for Continuous Oxygen Measurement in Portable Hypoxia Chambers.

BACKGROUND: Hypoxia-based cell culture experiments are routine and essential components of in vitro cancer research. Most laboratories use low-cost portable modular chambers to achieve hypoxic conditions for cell cultures, where the sealed chambers are purged with a gas mixture of preset O2 concentration. Studies are conducted under the assumption that hypoxia remains unaltered throughout the 48 to 72 hour duration of such experiments. Since these chambers lack any sensor or detection system to monitor gas-phase O2, the cell-based data tend to be non-uniform due to the ad hoc nature of the experimental setup. METHODOLOGY: With the availability of low-cost open-source microcontroller-based electronic project kits, it is now possible for researchers to program these with easy-to-use software, link them to sensors, and place them in basic scientific apparatus to monitor and record experimental parameters. We report here the design and construction of a small-footprint kit for continuous measurement and recording of O2 concentration in modular hypoxia chambers. The low-cost assembly (US$135) consists of an Arduino-based microcontroller, data-logging freeware, and a factory pre-calibrated miniature O2 sensor. A small, intuitive software program was written by the authors to control the data input and output. The basic nature of the kit will enable any student in biology with minimal experience in hobby-electronics to assemble the system and edit the program parameters to suit individual experimental conditions. RESULTS/CONCLUSIONS: We show the kit's utility and stability of data output via a series of hypoxia experiments. The studies also demonstrated the critical need to monitor and adjust gas-phase O2 concentration during hypoxia-based experiments to prevent experimental errors or failure due to partial loss of hypoxia. Thus, incorporating the sensor-microcontroller module to a portable hypoxia chamber provides a researcher a capability that was previously available only to labs with access to sophisticated (and expensive) cell culture incubators.