A paper microfluidic cartridge for automated staining of malaria parasites with an optically transparent microscopy window

Abstract

A paper microfluidic cartridge for the automated staining of malaria parasites (Plasmodium) with acridine orange prior to microscopy is presented. The cartridge enables simultaneous, sub-minute generation of both thin and thick smears of acridine orange stained parasites. Parasites are stained in a cellulose matrix, after which the parasites are ejected via capillary forces into an optically transparent chamber. The unique slanted design of the chamber ensures that a high percentage of the stained blood will be of the required thickness for a thin smear, without resorting to spacers or other methods that can increase production cost or require tight quality controls. A hydrophobic snorkel facilitates the removal of air bubbles during filling. The cartridge contains both a thin smear region, where a single layer of cells is presented unobstructed, for ease of species identification, and a thick smear region, containing multiple cell layers, for enhanced limit of detection.

Microfluidics for sperm research

“…Earlier versions of paper microfluidic chips were opaque cellulosebased chips. However, these devices fall short when there is need for optical microscopic imaging necessitating an optical window specifically for imaging purposes [50]. Optically transparent paper-based chips (OTC) are chemically and biologically compatible, and they are able to easily accommodate fluid flow with capabilities comparable to, if not better than, PMMA/PDMS-based chips.…”

On the Slow Diffusion of Point-of-Care Systems in Therapeutic Drug Monitoring

“…Previously, they were confined to clinically important analyses that require only a yes/no accuracy answer, but no sensitive quantification of the marker. These analyses can be performed with dip test strips and lateral flow tests, such as tests for infection markers for human immunodeficiency virus, hepatitis C virus, hepatitis B (Lee et al, 2010; Gong et al, 2014), tubercolosis (Tsai et al, 2013), malaria (Horning et al, 2014), tests for the presence/absence of multi drug resistance Staphylococcus aureu s in pre-surgical screening (Dutta and Dutta, 2006; Yetisen et al, 2013), or the pregnancy test. The latter is another textbook example of lateral flow tests, based on colorimetric detection of the analyte on a paper strip enclosed in a disposable plastic cassette, which provides an internal control, and a simple yes/no answer (Mark et al, 2010).…”

Paper microchip with a graphene-modified silver nano-composite electrode for electrical sensing of microbial pathogens

“…Recently, various classes of paper- and plastic-based materials have opened a new paradigm in developing a wide range of low-cost and disposable biosensing devices with significant potential for field applications in resource-limited settings. 4–9 Such devices are easy-to-fabricate, mass-producible, disposable, and inexpensive and can be integrated with various detection modalities, such as fluorescence, 10–12 electrochemical, 13–15 photoelectrochemical, 16 electrochemiluminescence 17, 18 and colorimetric. 19–21 …”