Metagenomic detection of phage-encoded platelet-binding factors in the human oral cavity.

The human oropharynx is a reservoir for many potential pathogens, including streptococcal species that cause endocarditis. Although oropharyngeal microbes have been well described, viral communities are essentially uncharacterized. We conducted a metagenomic study to determine the composition of oropharyngeal DNA viral communities (both phage and eukaryotic viruses) in healthy individuals and to evaluate oropharyngeal swabs as a rapid method for viral detection.

Acoustic particle filter with adjustable effective pore size for automated sample preparation.

This article presents analysis and optimization of a microfluidic particle filter that uses acoustic radiation forces to remove particles larger than a selected size by adjusting the driving conditions of the piezoelectric transducer (PZT). Operationally, the acoustic filter concentrates microparticles to the center of the microchannel, minimizing undesirable particle adsorption to the microchannel walls. Finite element models predict the complex two-dimensional acoustic radiation force field perpendicular to the flow direction in microfluidic devices.

Sample preparation: the weak link in microfluidics-based biodetection.

As a broad generalization, clinicians and laboratory personnel who use microfluidics-based automated or semi-automated instrumentation to perform biomedical assays on real-world samples are more pleased with the state of the assays than they are with the state of the front-end sample preparation. The end-to-end procedure requires one to collect, manipulate, prepare, and analyze the sample. The appeal of microfluidics for this procedure is partly based on its combination of small size and its ability to process very small liquid volumes, thus minimizing the use of possibly expensive reagents.

A minisonicator to rapidly disrupt bacterial spores for DNA analysis.

Concerns about the use of anthrax spores as a weapon of mass destruction have motivated the development of portable instruments capable of detecting and monitoring a suspected release of the agent. Optimal detection of bacterial spores by PCR requires that the spores be disrupted to make the endogenous DNA available for amplification. The entire process of spore lysis, PCR, and detection can take several hours using conventional methods and instruments.

Characterization of the sensitivity of side scatter in a flow-stream waveguide flow cytometer.

Background: We previously reported a new optical configuration, in which both the side scatter and the fluorescence are collected using the index-guided, total internal reflection of a flow stream in air (the flow-stream waveguide).

Methods: Using a mixture of 0.202-microm and 0.