Experimental investigation of confinement effect in single molecule amplification via real-time digital PCR on a multivolume droplet array SlipChip.

Background: Digital polymerase chain reaction (digital PCR) is an important quantitative nucleic acid analysis method in both life science research and clinical diagnostics. One important hypothesis is that by physically constraining a single nucleic acid molecule in a small volume, the relative concentration can be increased therefore further improving the analysis performance, and this is commonly defined as the confinement effect in digital PCR. However, experimental investigation of this confinement effect can be challenging since it requires a microfluidic device that can generate partitions of different volumes and an instrument that can monitor the kinetics of amplification.

Multiplex Digital Immunoassays with Reduced Pre-partition Reaction Massively Parallel Reagent Delivery on a Bead-Based SlipChip.

The emergence of digital immunoassays has advanced the sensitivity of protein analysis to ultrahigh sensitivity at the attomolar level. However, the background signal generated by the premixing of immunocomplexes and fluorogenic substrates can limit the precise quantification, especially in multiplexed assays. Herein, a bead-based SlipChip (bb-SlipChip) microfluidic device capable of massively parallel two-step sample loading is presented.

Multiplex Digital Polymerase Chain Reaction on a Droplet Array SlipChip for Analysis of Mutations in Pancreatic Cancer.

Pancreatic cancer is a terminal disease with high mortality and very poor prognosis. A sensitive and quantitative analysis of mutations in pancreatic cancer provides a tool not only to understand the biological mechanisms of pancreatic cancer but also for diagnosis and treatment monitoring. Digital polymerase chain reaction (PCR) is a promising tool for mutation analysis, but current methods generally require a complex microfluidic handling system, which can be challenging to implement in routine research and point-of-care clinical diagnostics.

Parallel multistep digital analysis SlipChip demonstrated with the quantification of nucleic acid by digital LAMP-CRISPR.

Digital biological analysis compartmentalizes targets of interest, such as nucleic acids, proteins, and cells, to a single event level and performs detection and further investigation. Microfluidic-based digital biological analysis methods, including digital PCR, digital protein analysis, and digital cell analysis, have demonstrated superior advantages in research applications and clinical diagnostics. However, most of the methods are still based on a one-step "divide and detect" strategy, and it is challenging for these methods to perform further parallel manipulation of reaction partitions to achieve "divide, manipulate, and analyze" capabilities.

Slip formation of a high-density droplet array for nucleic acid quantification by digital LAMP with a random-access system.

Digital nucleic acid analysis (digital NAA) is an important tool for the precise quantification of nucleic acids. Various microfluidic-based approaches for digital NAA have been developed, but most methods require complex auxiliary control instruments, cumbersome device fabrication, or inconvenient preparation processes. A SlipChip is a microfluidic device that can generate and manipulate liquid partitions through simple movements of two microfluidic plates in close contact.

Self-partitioning SlipChip for slip-induced droplet formation and human papillomavirus viral load quantification with digital LAMP.

Human papillomavirus (HPV) is one of the most common sexually transmitted infections worldwide, and persistent HPV infection can cause warts and even cancer. Nucleic acid analysis of HPV viral DNA can be very informative for the diagnosis and monitoring of HPV. Digital nucleic acid analysis, such as digital PCR and digital isothermal amplification, can provide sensitive detection and precise quantification of target nucleic acids, and its utility has been demonstrated in many biological research and medical diagnostic applications.

Slip Molding for Precision Fabrication of Microparts.

Microparts with precise sizes, custom shapes, and a wide selection of materials have various applications, including biomedical microelectromechanical systems (MEMS), drug delivery, single-cell studies, and tissue engineering. Janus microparts containing multiple components are also demonstrated for biomolecule analysis, cell-cell interaction studies, and self-assembly. Small-footprint, affordable, and rapid technologies to fabricate microparts with customized morphologies and a wide selection of materials are highly desired.

Slip-driven microfluidic devices for nucleic acid analysis.

Slip-driven microfluidic devices can manipulate fluid by the relative movement of microfluidic plates that are in close contact. Since the demonstration of the first SlipChip device, many slip-driven microfluidic devices with different form factors have been developed, including SlipPAD, SlipDisc, sliding stripe, and volumetric bar chart chip. Slip-driven microfluidic devices can be fabricated from glass, quartz, polydimethylsiloxane, paper, and plastic with various fabrication methods: etching, casting, wax printing, laser cutting, micromilling, injection molding, etc.