Label-Free Continuous Cell Sorting Using Optofluidic Chip.

In the field of biomedicine, efficiently and non-invasively isolating target cells has always been one of the core challenges. Optical fiber tweezers offer precise and non-invasive manipulation of cells within a medium and can be easily integrated with microfluidic systems. Therefore, this paper investigated the mechanism of cell manipulation using scattering force with optical fiber tweezers.

Virtual Multiplexing Chamber-Based Digital PCR for Camel Milk Authentication Applications.

In this work, we proposed a chamber-based digital PCR (cdPCR) microfluidic device that is compatible with fluorescence imaging systems for milk adulteration detection. The device enables the digitalization of PCR reagents, which are loaded into microchambers, and subsequent thermocycling for DNA amplification. Then, fluorescence images of the microchambers are captured and analyzed to obtain the total number of positive chambers, which is used to calculate the copy numbers of the target DNA, enabling accurate quantitative detections to determine intentional milk adulteration from accidental contaminations.

An integrated digital polymerase chain reaction chip for multiplexed meat adulteration detection.

Meat adulteration detection is a common concern of consumers. Here, we proposed a multiplex digital polymerase chain reaction method and a low-cost device for meat adulteration detection. Using a polydimethylsiloxane microfluidic device, polymerase chain reaction reagents could be pump-free loaded into microchambers (40 × 40 chambers) automatically.

Easy-to-Operate Co-flow Step Emulsification Device for Droplet Digital Polymerase Chain Reaction.

Digital polymerase chain reaction (PCR) plays important roles in the detection and quantification of nucleic acid targets, while there still remain challenges including high cost, complex operation, and low integration of the instrumental system. Here, in this work, a novel microfluidic chip based on co-flow step emulsification is proposed for droplet digital PCR (ddPCR), which can achieve droplet generation, droplet array self-assembly, PCR amplification, and fluorescence detection on a single device. With the combination of single-layer lithography and punching operation, a step microstructure was constructed and it served as the key element to develop a Laplace pressure gradient at the Rayleigh-Plateau instability interface so as to achieve droplet generation.

Pre-Degassed Microfluidic Chamber-Based Digital PCR Device for Meat Authentication Applications.

Droplet digital polymerase chain reaction (ddPCR) suffers from the need for specific equipment and skilled personnel; thus, we here present a chamber-based digital PCR microfluidic device that is compatible with fluorescence image read-out systems and removes bubbles by a pre-degassed microfluidic device that consists of a pilot channel and micro chamber arrays. Digitalized PCR reagents are introduced into micro chambers, and thermocycles are taken to perform a DNA amplification process. Then, fluorescence images of a micro chamber array are read out and analyzed to obtain the total number of positive chambers.

Fluid mixing in droplet-based microfluidics with T junction and convergent-divergent sinusoidal microchannels.

To explore and utilize the advantages of droplet-based microfluidics, hydrodynamics, and mixing process within droplets traveling though the T junction channel and convergent-divergent sinusoidal microchannels are studied by numerical simulations and experiments, respectively. In the T junction channel, the mixing efficiency is significantly influenced by the twirling effect, which controls the initial distributions of the mixture during the droplet formation stage. Therefore, the internal recirculating flow can create a convection mechanism, thus improving mixing.