Reconfigurable multiplexed point of Care System for monitoring type 1 diabetes patients

Abstract

At the point of care (POC), on-side clinical testing allows fast biomarkers determination even in resource-limited environments. Current POC systems rely on tests selective to a single analyte or complex multiplexed systems with important portability and performance limitations. Hence, there is a need for handheld POC devices enabling the detection of multiple analytes with accuracy and simplicity. Here we present a reconfigurable smartphone-interfaced electrochemical Lab-on-a-Chip (LoC) with two working electrodes for dual analyte determination enabling biomarkers' selection in situ and on-demand. Biomarkers selection was achieved by the use of electrodepositable alginate hydrogels. Alginate membranes containing either glucose oxidase (GOx) or lactate oxidase (LOx) were selectively electrodeposited on the surface of each working electrode in around 4 min, completing sample measurement in less than 1 min. Glucose and lactate determination was performed simultaneously and without cross-talk in buffer, fetal bovine serum (FBS) and whole blood samples, the latter being possible by the sizeexclusion filtration capacity of the hydrogels. At optimal conditions, glucose and lactate were determined in a wide linear range (0 -12 mM and 0 -5 mM, respectively) and with high sensitivities (0.24 and 0.54 µA cm -2 mM -1 , respectively), which allowed monitoring of Type-1 diabetic patients with a simple dual analysis system. After the measurement, membranes were removed by disaggregation with the calcium-chelator phosphate buffer. At this point, new membranes could be electrodeposited, this time being selective to the same or another analyte. This conferred the system with on-demand biomarkers' selection capacity. The versatility and flexibility of the current architecture is expected to impact in POC analysis in applications ranging from homecare to sanitary emergencies.

Smartphone-based mobile biosensors for the point-of-care testing of human metabolites

“… Target Accessories LOD (M) Linear range (M) Ref. Blood β Ketone Test strip, medical dongle, OTG wire 1 ​× ​10 −6 1 ​× ​10 −6 -6.1 ​× ​10 −3 [ 98 ] Uric acid Screen-printed electrodes Otg, three-electrode, detector 5.4 ​× ​10 −6 2.5 ​× ​10 −5 -2 ​× ​10 −4 [ 120 ] Glucose Umed, cable, glucose test Strip, otg wire – 2.78 ​× ​10 −3 -2.78 ​× ​10 −2 [ 96 ] Glucose SWCNT thin films, microcontroller, wireless signal processor, glucose sensor 5 ​× ​10 −5 5 ​× ​10 −5 -1 ​× ​10 −3 5 ​× ​10 −2 -1 [ 100 ] Glucose Imed three-electrode multi-potentiostat, wifi-based microcontroller – 1 ​× ​10 −3 -1 ​× ​10 −2 [ 101 ] Glucose Printed circuit boards, ambient light shielding 2.4 ​× ​10 −2 6.5 ​× ​10 −2 -7.5 ​× ​10 −1 [ 103 ] Glucose Three-electrode system, Bluetooth, chipset, lithium, Battery 1.5 ​× ​10 −5 3 ​× ​10 −5 -1.1 ​× ​10 −3 [ 121 ] Glucose/Lactate ΜPotentiostat, four electrodes silicon chips 1.8 ​× ​10 −4 /1.2 ​× ​10 −4 0–1.2 ​× ​10 −2 /0–5 ​× ​10 −3 [ 122 ] …”

Recent Applications of Point-of-Care Devices for Glucose Detection on the Basis of Stimuli-Responsive Volume Phase Transition of Hydrogel

“…Finally, based on reuse. In addition to covalently immobilization, using local electrodeposition method to prepare alginate hydrogels on the electrode surface can also achieve repeatedly use due to the reversibly degrading in calciumchelator phosphate buffer [51].…”

Electrochemical detection of ascorbic acid in artificial sweat using a flexible alginate/CuO-modified electrode

“…The sensor is fabricated via electrodeposition of an alginate membrane using a precursor mixed with CuO NPs on gold electrodes evaporated on a light-weight polyimide support [ 42 ]. The alginate membrane, which is reported to be biocompatible and permeable to the diffusion of the electrochemical substrates but impermeable to cells or large particles, has previously been used to trap enzymes for glucose and lactate determination [ 17 , 43 ] and carbon nanotubes to measure microbial activity [ 44 ]. Here, we trap CuO NPs from a commercially available and low-cost nanopowder to make use of their natural interaction with ascorbic acid previously mentioned.…”