Thread‐based microfluidic chips as a platform to assess acetylcholinesterase activity

Abstract

In this paper, a microfluidic thread-based analytical device (μTAD) to assess the activity of acetylcholinesterase (AChE) via colorimetric analylsis is described. Fabrication of the device consists of two platforms, both with a nylon thread trifurcated into three channels terminating at open analysis sites at the end of the thread. 5,5'-Dithiobis-(2-nitrobenzoic acid) (DTNB) was spotted and dried on the analysis sites. Acetylthiocholine iodide (ATC) (or cysteine, Cys) is transported through an inlet channel of the nylon thread by capillary action due to the hydrophilic nature of nylon. AChE is transported through the other inlet channel and mixes with the ATC (or Cys) as they travel up to the analysis sites. As the solution reaches the analysis sites, an intense yellow color change occurs indicating the reaction of the thiol with DTNB to produce the yellow anion TNB . The sites are then dried, scanned, yielding a linear range of inverse yellow mean intensity versus substrate concentration. An IC value (1.74 nM) with a known inhibitor, neostigmine bromide (NB), is obtained on the device. The multiplex design enables triplicate data collection in a device that is easy to use. μTADs have great potential to be employed in a myriad of tests including point-of-care diagnostic devices for resource-challenged settings.

Thread based electrofluidic platform for direct metabolite analysis in complex samples

“…The second group are based upon single threads, which generally involve much smaller solution volumes, as in these examples the flow within the strands of the thread is confined to one direction. The use of this later platform has been applied to bacteria isolation and quantification [24], chemotaxis studies for cell culture systems [25], immunoassays [26,27], blood typing [28], chemical synthesis [29], and the determination of nucleic acids [30,31], proteins [4,7,29,[31][32][33][34], glucose [29,[35][36][37], drugs [38], small ions [6,8,32,39] and metals [40]. Several detection techniques have been used for these various applications, with the most common, albeit the least sensitive, being simple colorimetric detection.…”

Enzyme‐linked immunosorbent assays (ELISA) based on thread, paper, and fabric

“…In addition to paper, thread has recently been integrated into microfluidics‐based technologies . We recently described a microfluidic thread‐based analytical device (μTAD) to assess the activity of acetylcholinesterase (AChE) via colorimetric analysis . The μTAD was fabricated from nylon thread placed on a piece of tape, with one end of the thread trifurcated to serve as the detection sites.…”

Thread- and Capillary Tube-Based Electrodes for the Detection of Glucose and Acetylthiocholine

“…Compared with earlier work, the detection site of the thread electrodes was significantly smaller in size (cm 2 scale to ~5 mm 2 ) [ 33 , 34 ]. The minimization of the electrode, along with the implementation of microfluidic materials, allowed for a significant decrease in solution volume (from 90 µL in earlier work to 12 and 30 µL for the paper and bubble wrap platforms, respectively) [ 39 , 40 ]. Despite the decrease in electrode size and solution volume, the results obtained are comparable to the results obtained in past work and provided reproducible results.…”