The A2 MicroArray System: an open platform for multiplex immunoassay development
The introduction of the microarray with its ability to globally interrogate a sample for a multitude of factors (e.g. gene expression monitoring; biomarker discovery) has quickly brought us to a new testing paradigm. The advent of “omics” driven parallel processing for quantitative biology has created new opportunities for assay development. Most attractive are turn-key platforms that offer the ability to simultaneously measure in a quantitative manner multiple analytes of interest across multiple samples, i.e. the multiplexed assay. Thus, microarrays have become very popular for the multiplex analysis of both nucleic acids and proteins. Planar slide microarrays, bead-based flow-cytometer platforms, and microplate-based array formats have been adopted for this purpose. In view of the multigenic nature of disease and the inter-relationships and complexities at the genomic, proteomic and metabolomic levels it is most certain that multiplex diagnostics and related screening technologies have a bright future. Microarray-based platforms continue to play a key role in the development of these assays. Click here to download this article as a PDF.
Automated nanoliter solution deposition for total reflection x-ray flourescence analysis of semiconductor samples
In this study, a BioDot BioJet dispensing system was investigated as a nanoliter sample deposition method for total reflection X-ray fluorescence (TXRF) analysis. The BioDot system was programmed to dispense arrays of 20 nL droplets of sample solution on Si wafers. Each 20 nL droplet was approximately 100 μm in diameter. A 10×10 array (100 droplets) was deposited and dried in less than 2 min at room temperature and pressure, demonstrating the efficiency of the automated deposition method. Solutions of various concentrations of Ni and Ni in different matrices were made from stock trace element standards to investigate of the effect of the matrix on the TXRF signal. The concentrations were such that the levels of TXRF signal saturation could be examined. Arrays were deposited to demonstrate the capability of drying 100 μL of vapor phase decomposition-like residue in the area of a typical TXRF detector. Click here to download this article as a PDF.
Setting Up and Running a Protein Microarray Core Facility
Microarray manufacturing is an area that is plagued with numerous technical challenges due, in part, to the complexity of the systems involved and to the variety of proteins and potential assays used. Click here to download this article as a PDF.
In-line Processing Trends for Lateral-flow Immunoassay Manufacturing
This article reviews current trends in manufacturing processes that IVD companies are implementing to achieve higher performance reproducibility from test to test, as measured by coefficient variability (CV), and better efficiency for high volume manufacturing. This article also focuses on processes such as application of various chemistries onto supporting materials, drying of such porous materials, and laminating and cutting all processed materials into finished test strips that are adequate for LFIAs. Click here to download this article as a PDF.
Low Volume Dispensing of Biomaterials for Biosensor and other Related Diagnostic Tests
Following advances in microelectronics, biosensor designs are becoming increasingly complex, and focused on miniaturization. The demand for simultaneous measurement of multiple analytes has made sensor arrays more the norm than the exception. As a result of this demand, and the advancing capabilities of patterning technologies, research and development programs aimed at sensor arrays containing tens to thousands of individual sensors in devices on the order of a square centimeter are underway. Fabrication of these devices typically requires reagent-dispensing approaches capable of delivering volumes ranging from the low microliters to picoliters. Reductions in volume reduce cost of expensive reagents, increase surface dependant reaction rates, and promote adoption of multiplexed diagnostic devices. These benefits have seen low volume dispensing applied to various research areas including Biosensors, Biochips, Protein Arrays, and Cell Arrays. Dispensing systems used must be compatible with a wide range of reagent classes, including organic solvents, biological fluids, polymeric solutions, as well as the traditional combination of buffer and enzymes. Systems must be robust enough to produce hundreds of thousands to millions of dispenses with a high level of precision and accuracy. Lastly these systems must function in a production environment using less skilled labor and also subject to rigorous regulatory requirements. This article reviews process parameters that impact accuracy, precision and reproducibility as measured by coefficient of variation (CV) of drop volume. Reduced variability is the key to minimizing rejected parts and other manufacturing costs, as well as to gain acceptance by the medical community and patients. Variability can be minimized at the level of chemical formulation, inclusion of appropriate electrode controls and regular re-calibration by specialists or patients. However, reduced variability in dispensed volumes remains essential. Click here to download this article as a PDF.