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This protocol will guide you through the process of paper microfluidic chip preparation via wax printing technique. This protocol does not include instruction on how to design the microfluidic chip. The authors suggest designing in SolidWorks, creating a SolidWorks drawing of the design, and saving as PDF before printing.

This protocol describes how to make MES buffers for covalently coupling proteins to carboxylated polystyrene particles via EDAC. Adapted from Bangs Laboratories Inc. TechNote 205 Covalent Coupling. Three buffers are made from 2-(N-morpholino)ethanesulfonic (MES) acid with varying pH. The three buffers are referred to as : Activation buffer (acidic for activating the carboxyl group on particles for EDAC reaction) Coupling buffer (alkaline for coupling protein to o-acylisourea on particle surface created by EDAC reaction) Storage buffer (for storing particles while preventing degradation and self aggregation)

Abstract Mechanical stimuli play important roles on the growth, development, and behavior of tissue. A simple and novel paper-based in vitro tissue chip was developed that can deliver two types of mechanical stimuli—local compression and shear flow—in a programmed manner. Rat vascular endothelial cells (RVECs) were patterned on collagen-coated nitrocellulose paper to create a tissue chip. Localized compression and shear flow were introduced by simply tapping and bending the paper chip in a programmed manner, utilizing an inexpensive servo motor controlled by an Arduino microcontroller and powered by batteries. All electrical compartments and a paper-based tissue chip were enclosed in a single 3D-printed enclosure, allowing the whole device to be independently placed within an incubator. This simple device effectively simulated in vivo conditions and induced successful RVEC migration in as early as 5 h. The developed device provides an inexpensive and flexible alternative for delivering mechanical stimuli to other in vitro tissue models. Graphical abstract

This protocol describes how to serially dilute and plate cultured bacteria in suspension for quantification.

This protocol details how to use ImageJ software to create a composite image from fluorescence images taken with a microscope.

This protocol details how to electrospin a PCL:PEG copolymer onto glass cover slip.

This protocol details how to spin coat a thin layer of PMMA on a glass cover slip.

The recent Zika virus (ZIKV) outbreak has prompted the need for field-ready diagnostics that are rapid, easy-to-use, handheld, and disposable while providing extreme sensitivity and specificity. To meet this demand, we developed a wax-printed paper microfluidic chip utilizing reverse transcription loop-mediated isothermal amplification (RT-LAMP). The developed simple and sensitive ZIKV assay was demonstrated using undiluted tap water, human urine, and diluted (10%) human blood plasma. Paper type, pore size, and channel dimension of various paper microfluidic chips were investigated and optimized to ensure proper filtration of direct-use biological samples (tap water, urine, and plasma) during capillary action-driven flow. Once ZIKV RNA has flowed and reached to a detection area of the paper microfluidic chip, it was excised for the addition of an RT-LAMP mixture with a pH indicator, then placed on a hot plate at 68 °C. Visible color changes from successful amplification were observed in 15 minutes and quantified by smartphone imaging. The limit of detection was as low as 1 copy/μL. The developed platform can also be used for identifying other flaviviruses, such as Chikungunya virus (CHIKV) and Dengue virus (DENV), and potentially other quickly transmitted virus pathogens, towards field-based diagnostics.