A facile and rapid route to self-digitization of samples into a high density microwell array for digital bioassays

Static and Surfactant-Free Quasi-Double Emulsions as Programmable Microcrystallizers for Controllable Polymorphic Crystallization

“…To generate highly reproducible, uniform, and stable double-emulsion structures for facilely and flexibly controlling the polymorphic crystallization, we develop a QDE chip based on our previous works. 28 The QDE chip is schematically shown in Figure 1b, which is reversibly assembled from three layers: a polydimethylsiloxane (PDMS) channel layer, a PDMS well layer, and a supporting glass substrate. The channel layer contains an array of 667 parallel microfluidic channels used for IAP delivery, and all channels connect to an inlet port via a main channel.…”

Oil-Triggered and Template-Confined Dewetting for Facile and Low-Loss Sample Digitization

“…Although these “static” microfluidics digitization systems offer distinct advantages over the droplet-based approaches, most of them still need expensive control systems, auxiliary components, or complicated microfabrication to achieve sample digitization. More recently, to lessen the reliance on complex external equipment and facilitate sample digitization for end-users, a self-pumping mechanism based on the air solubility of polydimethylsiloxane (PDMS) was recently introduced for “static” sample digitization. − By taking advantage of the high air solubility of the predegassed PDMS substrate to generate the pumping pressure, this power-free sample digitization technology has minimized the number of liquid control components, which is favorable for portable applications. In most cases, the power-free self-digitization devices consist of an array of microchambers, and each row of microchamber is connected to a main microchannel.…”

“…Therefore, it remains challenging for microfluidics platforms to achieve rapid, cost-effective, and low-sample-loss digitization. To address these challenges, we recently presented a rapid and facile method for spontaneous sample digitization, which uses a reversible channel-well assembly chip coupled with a predegassing-based self-pumping mechanism to achieve an easy, fast, and large-scale sample partitioning. However, it requires tedious alignment and assembly due to the detachable channel-well configuration, which can hinder the use of this sample digitization method by nonspecialized users.…”

A hand-powered microfluidic system for portable and low-waste sample discretization

“…To ease the fluid operation for end-users, a degassing-driven pumping mechanism has recently been adopted to achieve sample self-digitization with minimal manual intervention. 35–41 Although this pumping mechanism simplifies the sample discretization operation, the degassing-based method has several serious drawbacks. First, the device must be degassed in a vacuum environment for more than 1 hour before use.…”

“…In this paper, we propose a hand-powered, low-cost, and portable system for fast discretization of small volume samples, intended to extend the digital bioassay technique to the field and point-of-care applications. Compared to our previously developed degassing-driven discretization systems, 37,39–41 this system includes two key features (as shown in Fig. 1): i) syringe-based vacuum that provides a compact negative pressure source for fluid driving; ii) dissolvable film sealing that not only creates a closed space for vacuum storage but also serves as a sacrificial valve for flow gating.…”