Assessing the performance of a robust multiparametric wearable patch integrating silicon-based sensors for real-time continuous monitoring of sweat biomarkers.

The development of wearable devices for sweat analysis has experienced significant growth in the last two decades, being the main focus the monitoring of athletes health during workouts. One of the main challenges of these approaches has been to attain the continuous monitoring of sweat for time periods over 1 h. This is the main challenge addressed in this work by designing an analytical platform that combines the high performance of potentiometric sensors and a fluidic structure made of a plastic fabric into a multiplexed wearable device. The platform comprises Ion-Sensitive Field-Effect Transistors (ISFETs) manufactured on silicon, a tailor-made solid-state reference electrode, and a temperature sensor integrated into a patch-like polymeric substrate, together with the component that easily collects and drives samples under continuous capillary flow to the sensor areas. ISFET sensors for measuring pH, sodium, and potassium ions were fully characterized in artificial sweat solutions, providing reproducible and stable responses. Then, the real-time and continuous monitoring of the biomarkers in sweat with the wearable platform was assessed by comparing the ISFETs responses recorded during an 85-min continuous exercise session with the concentration values measured using commercial Ion-Selective Electrodes (ISEs) in samples collected at certain times during the session. The developed sensing platform enables the continuous monitoring of biomarkers and facilitates the study of the effects of various real working conditions, such as cycling power and skin temperature, on the target biomarker concentration levels.

Multisensing Wearables for Real-Time Monitoring of Sweat Electrolyte Biomarkers During Exercise and Analysis on Their Correlation With Core Body Temperature.

Sweat secreted by the human eccrine sweat glands can provide valuable biomarker information during exercise. Real-time non-invasive biomarker recordings are therefore useful for evaluating the physiological conditions of an athlete such as their hydration status during endurance exercise. This work describes a wearable sweat biomonitoring patch incorporating printed electrochemical sensors into a plastic microfluidic sweat collector and data analysis that shows the real-time recorded sweat biomarkers can be used to predict a physiological biomarker. The system was placed on subjects carrying out an hour-long exercise session and results were compared to a wearable system using potentiometric robust silicon-based sensors and to commercially available HORIBA-LAQUAtwin devices. Both prototypes were applied to the real-time monitoring of sweat during cycling sessions and showed stable readings for around an hour. Analysis of the sweat biomarkers collected from the printed patch prototype shows that their real-time measurements correlate well (correlation coefficient ≥ 0.65) with other physiological biomarkers such as heart rate and regional sweat rate collected in the same session. We show for the first time, that the real-time sweat sodium and potassium concentration biomarker measurements from the printed sensors can be used to predict the core body temperature with root mean square error (RMSE) of 0.02 °C which is 71% lower compared to the use of only the physiological biomarkers. These results show that these wearable patch technologies are promising for real-time portable sweat monitoring analytical platforms, especially for athletes performing endurance exercise.

Method to calculate the protamine dose necessary for reversal of heparin as a function of activated clotting time in patients undergoing cardiac surgery.

Activated clotting time (ACT) has been used to monitor coagulation and guide management of anticoagulation control in patients undergoing cardiac surgery for decades. However, reversal of heparin with protamine is typically empirically based on total heparin administered. Dose-related adverse effects of protamine are well described. The aim of this study was to evaluate a heparin reversal strategy based on calculation of the protamine dose based on ACT measurements. We present a method using a mathematical formula based on the dose-response line (1). To check the formula, we performed a retrospective observational cohort study of 177 patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). The study group of 80 patients was administered the dose of protamine obtained using our formula, and the control group of 97 patients was administered the empirically calculated dose. The ACT returned to normal values in patients who were given doses of protamine that were calculated using our formula; all but two had a final ACT of 141. The application of the formula resulted in a significant reduction in the dose of protamine (p < .023). The formula we present is a valid method for calculating the dose of protamine necessary to neutralize heparin. This same method can be used working with a target ACT to adjust the dose of heparin. As a result of its functionality, it allows application on a daily basis standardizing the process. We believe that the formula we developed can be applied in all those procedures in which it is necessary to anticoagulate patients with heparin and later neutralization (cardiac surgery with or without CPB, vascular surgery, procedures of interventional cardiology, and extracorporeal depuration procedures).

Expression and purification of polyhistidine-tagged rotavirus NSP4 proteins in insect cells.

The rotavirus nonstructural NSP4 protein, a transmembrane endoplasmic reticulum-specific glycoprotein, has been described as the first viral enterotoxin. Purified NSP4 or a peptide corresponding to NSP4 residues 114-135 induces diarrhea in young mice. NSP4 has a membrane-destabilizing activity and causes an increase in intracellular calcium levels and chloride secretion by a calcium-dependent signalling pathway in eucaryotic cells. In this study, four recombinant baculoviruses were generated expressing the rotavirus NSP4 glycoprotein from the human strains Wa and Ito, the porcine strain OSU, and the simian strain SA11, which belong to two different NSP4 genotypes, A and B. The recombinant glycoproteins, expressed as polyhistidine-tagged molecules, were analyzed by Western blotting and immunoprecipitation. Newborn mice responded with diarrhea after inoculation with each of the recombinant NSP4 proteins.