Impedimetric array in polymer microfluidic cartridge for low cost point-of-care diagnostics

Abstract

Impedimetric array in polymer microfluidic cartridge for low cost point-of-care diagnostics, Biosensors and Bioelectronic, https://doi.ABSTRACT Deep Vein Thrombosis and pulmonary embolism (DVT/PE) is one of the most common causes of unexpected death for hospital in-patients. D-dimer is used as a biomarker within blood for the diagnosis of DVT/PE. We report a low-cost microfluidic device with a conveniently biofunctionalised interdigitated electrode (IDE) array and a portable impedimetric reader as a point-of-care (POC) device for the detection of Ddimer to aid diagnosis of DVT/PE. The IDE array elements, fabricated on a polyethylenenaphtalate (PEN) substrate, are biofunctionalised in situ after assembly of the microfluidic device by electropolymerisation of a copolymer of polypyrrole to which is immobilised a histidine tag anti-D-Dimer antibody. The most consistent copolymer films were produced using chronopotentiometry with an applied current of 5A for a period of 50 seconds using a two-electrode system. The quality of the biofunctionalisation was monitored using optical microscopy, chronopotentiometry curves and impedimetric analysis. Measurement of clinical plasma sample with a Ddimer at concentration of 437 ng/mL with 15 biofunctionalised IDE array electrodes gave a ratiometric percentage of sample reading against the blank with an average value of 124±15 at 95% confidence. We have demonstrated the concept of a low cost disposable microfluidic device with a receptor functionalised on the IDE array for impedimetric detection towards POC diagnostics. Changing the receptor on the IDE array would allow this approach to be used for the direct detection of a wide range of analytes in a low cost manner.

Fabrication Methods for Microfluidic Devices: An Overview

“…There is increasing interest within wearable and flexible electronics for diagnostic applications [ 216 , 217 , 218 ]. There are a wide range of examples, including skin-based sensors for wireless physiological monitoring for neonate and pediatric care [ 219 ], flexible sensors for wound management [ 220 ], DNA analysis using melting curve analysis with an integrated thin film heater [ 221 ], and impedimetric point-of-care diagnostic for selected biomarkers [ 222 ]. Integration of electronic functions can be based on printed organic semiconductor, or inorganic thin films or silicon chip devices which have advantages of functionality, performance, reliability, and power requirements.…”

“…Figure 8 A shows semi-additive R2R processes [ 224 ] that can be implemented for patterning of metal on a substrate, and Figure 8 B shows demonstration of producing the electrode layer for impedimetric detection described in [ 222 ] as a R2R process in copper, as a proof of concept. The process incorporates lamination of dry film photoresist, photolithography, development, etching, stripping of photoresist, and laser dicing and has the potential for extension to a wholly R2R manufactured microfluidic device.…”

“… ( A ) Hybrid integrated temperature sensor label from [ 224 ] under creative commons 3.0. ( B ) Impedimetric point-of-care diagnostic cartridge described in [ 222 ] with electrode layer joined to microfluidic body using adhesive layer. …”

Biomarkers for Point-of-Care Diagnosis of Sepsis

“…This is therefore a very promising approach, although the need for plasma instead of whole blood necessitates pre-analytical centrifugation. Lakey and co-workers reported an impedimetric electrode array within a polymer microfluidic cartridge that demonstrates an approach that could be used for multiplexed sensing of an array of sepsis biomarkers for low-cost point-of-care diagnostics [132].…”

Developments in Transduction, Connectivity and AI/Machine Learning for Point-of-Care Testing

“…Impedimetric sensing is also attractive since micro and nanofabrication techniques would allow development of the miniaturised transducers in a convenient manner. The potential of fabricating an impedimetric array in a polymer microfluidic cartridge has been demonstrated as a potential aid for diagnosis of Deep Vein Thrombosis/Pulmonary Embolism (DVT/PE) and towards low cost point-of-care diagnostics [17] An impedimetric array within a microfluidic cartridge could allow multiple measurements of a single biomarker or alternatively measurements of multiple biomarkers within the same microfluidic cartridge.…”