Cost-effective smartphone-based reconfigurable electrochemical instrument for alcohol determination in whole blood samples

• Published in: Biosensors & bioelectronics Vol. 117; pp. 736 - 742
• Main Authors: Aymerich, Joan, Márquez, Augusto, Terés, Lluís, Muñoz-Berbel, Xavier, Jiménez, Cecilia, Domínguez, Carlos, Serra-Graells, Francesc, Dei, Michele
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.10.2018
• Subjects: Alcohols - analysis; Alcohols - blood; Biosensing Techniques; Blood Alcohol Content; Blood Chemical Analysis - economics; Blood Chemical Analysis - instrumentation; Blood-alcohol concentration; Electrochemical Techniques; Electrodes; Horseradish Peroxidase; Humans; Lab-On-A-Chip Devices; Limit of Detection; Low-cost reusable point-of-care; Smartphone; Smartphone-based micro-potentiostat; Whole blood analysis; Smartphone-based micro-potentiostat; Blood-alcohol concentration; Whole blood analysis; Low-cost reusable point-of-care
• DOI: 10.1016/j.bios.2018.06.044
• ISSN: 0956-5663

The determination of ethanol intoxication in whole blood samples may open the opportunity for a precise and quick point-of-measurement in the ambit of medical emergency or law enforcement. In contrast with traditional techniques based on breath sampling, direct blood measurements present greater immunity to errors specially in case of unconscious or non-collaborative patients. In this context, a portable, sensitive and easy-to-use instrument is highly desirable. In the current work we present a smartphone-based µPotentiostat which combines a novel circuital technique for sensor readout digitalization with a reusable lab-on-a-chip (LoC) concept. Such system allows both chronoamperometric and cyclic voltammetry measurements with a reduced number of electronic components on a very compact PCB (38.5 × 22.5 mm2). Power, data-link and user interface are provided in combination with a standard smartphone, enabling cost-effectiveness and reconfigurability without sacrificing precision. The readout platform discussed in this work has been coupled to a LoC for point-of-care combining Pt electrodes microfabricated on silicon substrate for electrochemical measurement and a microfluidic structure of methacrylate for fluid management. Biosensing is enabled by in situ electrodeposition of a calcium alginate hydrogel containing horseradish peroxidase (HPR) and alcohol oxidase (AOx) for selective ethanol detection. Alginate membrane electrodeposition has been here optimized for rapid generation (2 min) and to retain the cellular fraction, thus allowing the measurement in whole blood samples. The µPotentiostat features a sensitivity of 36 nA/g L−1 to ethanol concentration in blood in the 0–1.25 g;L−1 range, with a limit of quantification (LoQ) of 4.5 nA, which is a suitable response for discerning the legal, illegal, severely illegal thresholds in a 40 µL sample of blood. •Rapid and precise point-of-measurements of ethanol intoxication in small volumes (40 µL) of whole blood sample.•Lab-on-a-chip based on calcium alginate hydrogels for selective and reliable ethanol determination in whole blood samples.•Low-cost µPotentiostat with a sensitivity of 36 nA/g L−1, a LoQ 4.5 nA in the 0–1.25 g L−1 ethanol concentration.