A solvent replenishment solution for managing evaporation of biochemical reactions in air-matrix digital microfluidics devices.

Digital microfluidics (DMF) is a powerful technique for sample preparation and analysis for a broad range of biological and chemical applications. In many cases, it is desirable to carry out DMF on an open surface, such that the matrix surrounding the droplets is ambient air. However, the utility of the air-matrix DMF format has been severely limited by problems with droplet evaporation, especially when the droplet-based biochemical reactions require high temperatures for long periods of time.

World-to-digital-microfluidic interface enabling extraction and purification of RNA from human whole blood.

Digital microfluidics (DMF) is a powerful technique for simple and precise manipulation of microscale droplets of fluid. This technique enables processing and analysis of a wide variety of samples and reagents and has proven useful in a broad range of chemical, biological, and medical applications. Handling of "real-world" samples has been a challenge, however, because typically their volumes are greater than those easily accommodated by DMF devices and contain analytes of interest at low concentration.

Multiplexed extraction and quantitative analysis of pharmaceuticals from DBS samples using digital microfluidics.

Background: Dried blood spot (DBS) sampling is emerging as a valuable technique in a variety of fields, including clinical and preclinical testing of pharmaceuticals. Despite this popularity, current DBS sampling and analysis processes remain laborious and time consuming. Digital microfluidics, a microscale liquid-handling technique, characterized by the manipulation of discrete droplets on open electrode arrays, offers a potential solution to these problems.

A versatile automated platform for micro-scale cell stimulation experiments.

Study of cells in culture (in vitro analysis) has provided important insight into complex biological systems. Conventional methods and equipment for in vitro analysis are well suited to study of large numbers of cells (≥ 10(5)) in milliliter-scale volumes (≥ 0.1 ml).

A microfluidic DNA library preparation platform for next-generation sequencing.

Next-generation sequencing (NGS) is emerging as a powerful tool for elucidating genetic information for a wide range of applications. Unfortunately, the surging popularity of NGS has not yet been accompanied by an improvement in automated techniques for preparing formatted sequencing libraries. To address this challenge, we have developed a prototype microfluidic system for preparing sequencer-ready DNA libraries for analysis by Illumina sequencing.

Digital microfluidics: a versatile tool for applications in chemistry, biology and medicine.

Digital microfluidics (DMF) has recently emerged as a popular technology for a wide range of applications. In DMF, nanoliter to microliter droplets containing samples and reagents can be manipulated to carry out a range of discrete fluidic operations simply by applying a series of electrical potentials to an array of patterned electrodes coated with a hydrophobic insulator. DMF is distinct from microchannel-based fluidics as it allows for precise control over multiple reagent phases (liquids and solids) in heterogeneous systems with no need for complex networks of connections, microvalves, or pumps.

Dried blood spot analysis by digital microfluidics coupled to nanoelectrospray ionization mass spectrometry.

Dried blood spot (DBS) samples on filter paper are surging in popularity as a sampling and storage vehicle for a wide range of clinical and pharmaceutical applications. For example, a DBS sample is collected from every baby born in the province of Ontario, Canada, for quantification of approximately one hundred analytes that are used to screen for 28 conditions, including succinylacetone (SA), a marker for hepatorenal tyrosinemia. Unfortunately, the conventional methods used to evaluate DBS samples for newborn screening and other applications are tedious and slow, with limited options for automated analysis.

A digital microfluidic method for dried blood spot analysis.

Blood samples stored as dried blood spots (DBSs) are emerging as a useful sampling and storage vehicle for a wide range of applications. Unfortunately, the surging popularity of DBS samples has not yet been accompanied by an improvement in automated techniques for extraction and analysis. As a first step towards overcoming this challenge, we have developed a prototype microfluidic system for quantification of amino acids in dried blood spots, in which analytes are extracted, mixed with internal standards, derivatized, and reconstituted for analysis by (off-line and in-line) tandem mass spectrometry.

A digital microfluidic method for in situ formation of porous polymer monoliths with application to solid-phase extraction.

We introduce the marriage of two technologies: digital microfluidics (DMF), a technique in which droplets are manipulated by application of electrostatic forces on an array of electrodes coated by an insulator, and porous polymer monoliths (PPMs), a class of materials that is popular for use for solid-phase extraction and chromatography. In this work, circular PPM discs were formed in situ by dispensing and manipulating droplets of monomer solutions to designated spots on a DMF device followed by UV-initiated polymerization. We used PPM discs formed in this manner to develop a digital microfluidic solid-phase extraction (DMF-SPE) method, in which PPM discs are activated and equilibrated, samples are loaded, PPM discs are washed, and the samples are eluted, all using microliter droplets of samples and reagents.

Folded emitters for nanoelectrospray ionization mass spectrometry.

Electrospray ionization (ESI) has revolutionized mass spectrometry (MS), providing a facile method for the ionization of macromolecules for analysis by mass. The development of nanoESI-MS has further extended the utility of ESI-MS, permitting the analysis of small-volume samples with enhanced sensitivity over conventional ESI-MS. Traditional nanoESI-MS experiments use pulled-glass capillary emitters, which are expensive to purchase and require specialized instruments and training to fabricate in-house.

Let's get digital: digitizing chemical biology with microfluidics.

Digital microfluidics (DMF) has recently emerged as a popular technology for a wide range of applications in chemical biology. In DMF, nL-mL droplets containing samples and reagents are controlled (i.e.

Multilayer hybrid microfluidics: a digital-to-channel interface for sample processing and separations.

Microchannels can separate analytes faster with higher resolution, higher efficiency and with lower reagent consumption than typical column techniques. Unfortunately, an impediment in the path toward fully integrated microchannel-based laboratories-on-a-chip is the integration of preseparation sample processing. In contrast, the alternative format of digital microfluidics (DMF), in which discrete droplets are manipulated on an array of electrodes, is well-suited for carrying out sequential chemical reactions such as those commonly employed in proteomic sample preparation.

Droplet-scale estrogen assays in breast tissue, blood, and serum.

Estrogen is a key hormone in human reproductive physiology, controlling ovulation and secondary sexual characteristics. In addition, it plays an important role in the pathogenesis of breast cancer. Indeed, estrogen receptor antagonists and aromatase inhibitors (which block estrogen biosynthesis) are primary drugs used for treatment and prevention in at-risk populations.

Digital microfluidics for automated proteomic processing.

Clinical proteomics has emerged as an important new discipline, promising the discovery of biomarkers that will be useful for early diagnosis and prognosis of disease. While clinical proteomic methods vary widely, a common characteristic is the need for (i) extraction of proteins from extremely heterogeneous fluids (i.e.

Digital microfluidic method for protein extraction by precipitation.

We present the first microfluidic method for extracting proteins from heterogeneous fluids by precipitation. The new method comprises an automated protocol for precipitation of proteins onto surfaces, rinsing the precipitates to remove impurities, and resolubilization in buffer for further analysis. The method is compatible with proteins representing a range of different physicochemical properties, as well as with complex mixtures such as fetal bovine serum and cell lysate.