Rapid Microbiology Screening in Pharmaceutical Workflows.

Recently advances in miniaturization and automation have been utilized to rapidly decrease the time to result for microbiology testing in the clinic. These advances have been made due to the limitations of conventional culture-based microbiology methods, including agar plate and microbroth dilution, which have long turnaround times and require physicians to treat patients empirically with antibiotics before test results are available. Currently, there exist similar limitations in pharmaceutical sterility and bioburden testing, where the long turnaround times associated with standard microbiology testing drive costly inefficiencies in workflows. These include the time lag associated with sterility screening within drug production lines and the warehousing cost and time delays within supply chains during product testing. Herein, we demonstrate a proof-of-concept combination of a rapid microfluidic assay and an efficient cell filtration process that enables a path toward integrating rapid tests directly into pharmaceutical microbiological screening workflows. We demonstrate separation and detection of Escherichia coli directly captured and analyzed from a mammalian (i.e., CHO) cell culture with a 3.0 h incubation. The demonstration is performed using a membrane filtration module that is compatible with sampling from bioreactors, enabling in-line sampling and process monitoring.

Mesoscale blood cell sedimentation for processing millilitre sample volumes.

We demonstrate the efficient separation of blood cells from millilitre volumes of whole blood in minutes using a simple gravity sedimentation device. Blood cell and plasma separation is often the initial step in clinical diagnostics, and reliable separation techniques have remained a major obstacle for the success of point-of-care or remote diagnostics. Unlike plasma collection devices that rely solely on microchannels that restrict sample volume and throughput, we demonstrate the use of a hybrid micro/mesoscale sedimentation chamber to enable >99% capture of cells from millilitre blood samples in less than two minutes.

Counting single molecules in sub-nanolitre droplets.

We demonstrate single biomolecule detection and quantification within sub-nanolitre droplets through application of Cylindrical Illumination Confocal Spectroscopy (CICS) and droplet confinement within a retractable microfluidic constriction.

Quantum dots in molecular detection of disease.

The unique photophysical properties of semiconductor quantum dots (QDs) have made them ideal for use as spectral labels and luminescent probes. In this review, applications are presented in which QDs function as active participants in nanoscale biosensor assemblies, where replacing traditional molecular fluorophores results in improved assay performance. Specific focus is on disease detection with applications including multiplexed target detection, mutation detection by coincidence analysis and QD-based FRET reporters for miRNA detection and DNA methylation analysis.

Coupling confocal fluorescence detection and recirculating microfluidic control for single particle analysis in discrete nanoliter volumes.

The recent proliferation of platforms designed to handle arrays of nano- and picolitre volumes is in response to the need to perform biological assays on discrete entities, such as single cells. However, a critical challenge associated with this trend for in vitro compartmentalization is the need for highly sensitive, yet low-volume detection platforms. In this paper, we coupled confocal fluorescence detection with recirculating microfluidic control to perform single particle DNA assays within five nL chambers. The performance of this low-volume assay was shown to match that of traditional single molecule detection platforms. However, volume requirements per measurement were nearly 3 orders of magnitude less than conventional systems, enabling future integration with lab-on-a-chip systems that require discrete or digitalized sample processing.