Thread/paper‐ and paper‐based microfluidic devices for glucose assays employing artificial neural networks

Abstract

This paper describes the fabrication of and data collection from two microfluidic devices: a microfluidic thread/paper based analytical device (μTPAD) and 3D microfluidic paper-based analytical device (μPAD). Flowing solutions of glucose oxidase (GOx), horseradish peroxidase (HRP), and potassium iodide (KI), through each device, on contact with glucose, generated a calibration curve for each platform. The resultant yellow-brown color from the reaction indicates oxidation of iodide to iodine. The devices were dried, scanned, and analyzed yielding a correlation between yellow intensity and glucose concentration. A similar procedure, using an unknown concentration of glucose in artificial urine, is conducted and compared to the calibration curve to obtain the unknown value. Studies to quantify glucose in artificial urine showed good correlation between the theoretical and actual concentrations, as percent differences were ≤13.0%. An ANN was trained on the four-channel CMYK color data from 54 μTPAD and 160 μPAD analysis sites and Pearson correlation coefficients of R = 0.96491 and 0.9739, respectively, were obtained. The ANN was able to correctly classify 94.4% (51 of 54 samples) and 91.2% (146 of 160 samples) of the μTPAD and μPAD analysis sites, respectively. The development of this technology combined with ANN should further facilitate the use of these platforms for colorimetric analysis of other analytes.

Recent advances in thread-based microfluidics for diagnostic applications

“…To achieve a tunable hydrophobicity in a thread-based microfluidic device, Choi et al (2018) used twelve-fold diluted polysiloxanes to partially change the hydrophilicity of the cotton thread to obtain desirable fluidic delay and optimum interaction between the antibody-functionalized gold nanoparticle probes and target antigen (Fig. Recently, the use of the thread-based microfluidics has been applied to immunoassays Mao et al, 2015a;Song et al, 2017), determination of nucleic acids , proteins Mao et al, 2015b;Nilghaz et al, 2014a;Ulum et al, 2016), glucose Lee et al, 2018;Yang et al, 2014a), virus (Weng and Neethirajan, 2018b), small ions (Jarujamrus et al, 2018;Yan et al, 2015), bacteria isolation and quantification , chemotaxis studies for cell culture systems Ramesan et al, 2016), blood typing (Nilghaz et al, 2014b), chemical synthesis (Banerjee et al, 2013) and metabolite analysis (Cabot et al, 2018). With the modification, more resultant complexes were generated and captured at the test zone thus enhanced the sensitivity (around 10-fold signal enhancement) significantly.…”

“…As shown in Fig. Lee et al (2018) designed a microfluidic thread/paper based analytical device (µTPAD) combined with artificial neural networks to quantify glucose in artificial urine. Thread was sewn to connect the sample pad and the test zone strips.…”

“…(B) Representative pictures of a control chip with glucose stantdard solution and an example of sample chip(Lee et al, 2018). Left hand side, exploded view of the chip.…”

Recent applications of paper‐based point‐of‐care devices for biomarker detection

“…LOC can be fabricated on different materials such as glass , silicon , PDMS , PMMA [, paper or a hybrid of PDMS/paper/glass . Presently, thread/PADs can also be fabricated as a simple platform for bioassays . In addition, a commonly used toner (a powder consisting of polymer [acrylate and styrene] and iron oxide or silicon dioxide ) in laser printers or photocopiers can be utilized as a novel and cost‐effective platform for LOC devices.…”

3D Multilayered paper‐ and thread/paper‐based microfluidic devices for bioassays

“…Using wax printing on μPADs has been previously studied and shown to be effective for biological assays . Wax printing can be manipulated to design a guide on paper that upon heating permeates the paper, creating a hydrophobic barrier . Incorporating wax with thread and paper can further enhance the simplicity and efficiency of μTPADs.…”