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

• Published in: Biosensors & bioelectronics Vol. 129; pp. 147 - 154
• Main Authors: Lakey, Andrew, Ali, Zulfiqur, Scott, Simon M., Chebil, Syrine, Korri-Youssoufi, Hafsa, Hunor, Santha, Ohlander, Anna, Kuphal, Mathias, Marti, Josep Samitier
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.03.2019; Elsevier
• Subjects: Analytical chemistry; Antibodies, Immobilized - chemistry; Biomarkers - analysis; Biomarkers - blood; Biosensing Techniques - instrumentation; Biotechnology; Chemical Sciences; Electric Impedance; Electrodes; Electropolymerisation; Equipment Design; Fibrin Fibrinogen Degradation Products - analysis; Humans; Impedimetric sensing; Interdigitated electrodes; Lab-On-A-Chip Devices; Life Sciences; Limit of Detection; Microfluidics; Point-of-care diagnostics; Point-of-Care Systems; Polyethylenes - chemistry; Polymerization; Polymers; Polymers - chemistry; Pulmonary Embolism - blood; Pyrroles - chemistry; Venous Thrombosis - blood; Point-of-care diagnostics; Electropolymerisation; Interdigitated electrodes; Impedimetric sensing; Microfluidics
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2018.12.054

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 D-dimer 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 5μA for a period of 50 s 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 D-dimer 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. •Biofunctionalisation of IDE array in microfluidic device with electropolymerisation.•Portable impedimetric reader for detection of D-dimer biomarker.•Quality of biofunctionalisation monitored using optical microscopy.•Properties of biofunctionalised layers using chronopotentiometry and impedance.•Measurement of clinical plasma sample of four biofunctionalised IDEs.