A Simple Paper Based Microfluidic Electrochemical Biosensor for Point‐of‐Care Cholesterol Diagnostics

Abstract

Paper based microfluidic devices have emerged as a simple and low cost platform for efficient clinical diagnostics. An effort has been made in the present work to develop a microfluidic cholesterol biosensor using paper based platform. Microfluidic channels have been fabricated by patterning filter paper (Whatman 1) using photolithography. SU 8 photoresist formed a hydrophobic barrier on the paper with microchannels of dimensions 1000 μm(w)×100 μm(t). A three electrode system was fabricated by simple mask printing of graphite as the working, as well as the counter electrodes, and silver as the reference electrode. The working electrode was modified using nickel oxide nanoparticles prepared using co‐precipitation method. Cholesterol oxidase enzyme is spotted on the test zone and chronoamperometric measurements are taken for different concentrations of cholesterol in the range of 0.12–10.23 mM, giving a quick and sensitive detection with a sensitivity of 24 µA mM−1 cm−2.

Biocompatible and flexible paper-based metal electrode for potentiometric wearable wireless biosensing

“…In previous works, paperbased electrodes were developed for the detection of biomolecules such as glucose and cortisol. Most of them employed amperometric and impedimetric methods combined with enzymes and redox mediators [6][7][8][9][10][11][12]. On the other hand, the modification of ion-sensitive membranes (ISMs) on a paper-based electrode will be useful for the detection of ions in biological fluids, such as sweat, as part of a potentiometric measurement system.…”

Electrochemical paper-based biosensors for point-of-care diagnostics: Detection methods and applications

“…Since the production of the first paper-based device attributed to Müller and Clegg [47] and the production of paper-based microfluidics by the Whitesides group, which was the first device for determination of glucose created through a photolithography technique [51], there have been a lot of developments in fabrication techniques and paper-based applications [52]. Generally, the fundamental techniques of PADs fabrication are photolithography [53], wax printing [54,55], inkjet [56], screen printing [57], laser treatment [58], and wet etching [59]. Of course, the fabrication techniques of PADs are similar to those of microfluidic PADs; they are based on the creation of hydrophilic zones for electrochemical detection with hydrophobic borders on paper to confine the flow of fluid inside the desired position.…”

“…Photolithography has a high resolution and good reproducibility, but it is disadvantageous due to the use of chemical solvents and expensive equipment [62,63]. Kaur et al [53] expanded a microfluidic paper-based cholesterol biosensor. They utilized a patterning filter paper (Whatman≠1) to fabricate microfluidic channels by photolithography.…”

Emerging Considerations for the Future Development of Electrochemical Paper‐Based Analytical Devices

“…In addition, the masks for photolithography can be prepared by different techniques such as the use of an inkjet printer or photocopying machine or being drawn by hand ,. As another example, Gupta and co‐authors have used photolithography to construct a paper‐based electrochemical microfluidic device for cholesterol diagnosis. The paper was spin‐coated with a photoresist, baked and then exposed to UV through a photomask, resulting in hydrophobic barriers.…”

“…1 filter paper dopamine, glucose and pH CV, amperometry and potentiometry [56] Whatman filter paper (qualitative, 114) miR-21 (miRNA) DPV [14b] Whatman chromatography paper 3 mm Staphylococcus aureus DPV [12a] Whatman No. 1 filter paper cholesterol amperometry [57] Whatman No. 1 filter paper alpha-Fetoprotein SWV [58] Whatman filter paper (qualitative, 4) influenza virus (H1 N1) DPV [59] Whatman No.…”