Flexible and disposable paper- and plastic-based gel micropads for nematode handling, imaging, and chemical testing

Abstract

Today, the area of point-of-care diagnostics is synonymous with paper microfluidics where cheap, disposable, and on-the-spot detection toolkits are being developed for a variety of chemical tests. In this work, we present a novel application of microfluidic paper-based analytical devices (μPADs) to study the behavior of a small model nematode, Caenorhabditis elegans. We describe schemes of μPAD fabrication on paper and plastic substrates where membranes are created in agarose and Pluronic gel. Methods are demonstrated for loading, visualizing, and transferring single and multiple nematodes. Using an anthelmintic drug, levamisole, we show that chemical testing on C. elegans is easily performed because of the open device structure. A custom program is written to automatically recognize individual worms on the μPADs and extract locomotion parameters in real-time. The combination of μPADs and the nematode tracking program provides a relatively low-cost, simple-to-fabricate imaging and screening assay (compared to standard agarose plates or polymeric microfluidic devices) for non-microfluidic, nematode laboratories.

Scan4CFU: Low-cost, open-source bacterial colony tracking over large areas and extended incubation times

“…Besides applications in microbiology, our bacterial enumeration system can be diversified for imaging, counting, and tracking other microorganisms on agar plates, such as C. elegans and parasitic nematodes [17][18][19][20]. For this purpose, a number of open source image processing and analysis techniques are freely available through the ImageJ software and the scientific imaging community [14,21,22]. Finally, the presented system offers a range of possibilities for STEM education and direct hands-on training for undergraduate and graduate students who want to tinker with the system and methods to optimize its performance and throughout at a low costÀsomething that is difficult with commercial cell trackers.…”

Paper-based in vitro tissue chip for delivering programmed mechanical stimuli of local compression and shear flow

“…On the other hand, papers can provide an ECM-like fibrous structure and porosity. Additionally, papers are flexible and can be easily modified (e.g., cut, fold, create hydrophobic pattern, and even used as a support structure for hydrogel), inexpensive, and applied with the flow referred to as paper-based microfluidic technology [21][22][23]. In this work, the paper coated with collagen was used as a "flexible" substrate for cell culture, effectively delivering both compression and shear flow on a single platform within our device.…”

Paper-Based Analytical Device for Real-Time Monitoring of Egg Hatching in the Model Nematode Caenorhabditis elegans

“…In addition to labs-on-a-chip, microfluidic paper-based analytical devices (μPADs), which were first reported by Whiteside’s group, have become attractive for monitoring biomarkers, cultivating, and chemical monitoring in microorganisms DNA because these devices are of low cost, show ease of fabrication, and use biocompatible materials. − Regarding the study of model organisms, μPAD- and C. elegans-tracking programs combined with stacked polycarbonate layers have been developed to form a 3D structure for culturing, trapping, and monitoring of C. elegans in worm experiments .…”