We demonstrate a conduit for the delivery of a step change in the DNA analysis process: A fully integrated instrument for the analysis of multiplex short tandem repeat DNA profiles from reference buccal samples is described and is suitable for the processing of such samples within a forensic environment such as a police custody suite or booking office. The instrument is loaded with a DNA processing cartridge which incorporates on-board pumps and valves which direct the delivery of sample and reagents to the various reaction chambers to allow DNA purification, amplification of the DNA by PCR, and collection of the amplified product for delivery to an integral CE chip. The fluorescently labeled product is separated using micro capillary electrophoresis with a resolution of 1.2 base pairs (bp) allowing laser induced fluorescence-based detection of the amplified short tandem repeat fragments and subsequent analysis of data to produce a DNA profile which is compatible with the data format of the UK DNA database. The entire process from taking the sample from a suspect, to database compatible DNA profile production can currently be achieved in less than 4 h. By integrating such an instrument and microfluidic cartridge with the forensic process, we believe it will be possible in the near future to process a DNA sample taken from an individual in police custody and compare the profile with the DNA profiles held on a DNA Database in as little as 3 h.

The microfluidic integration of an entire DNA analysis workflow on a fully integrated miniaturized instrument is reported using lab-on-a-chip automation to perform DNA fingerprinting compatible with CODIS standard relevant to the forensic community. The instrument aims to improve the cost, duration, and ease of use to perform a "sample-to-profile" analysis with no need for human intervention. The present publication describes the operation of the three major components of the system: the electronic control components, the microfluidic cartridge and CE microchip, and the optical excitation/detection module. Experimental details are given to characterize the level of performance, stability, reliability, accuracy, and sensitivity of the prototype system. A typical temperature profile from a PCR amplification process and an electropherogram of a commercial size standard (GeneScan 500™, Applied Biosystems) separation are shown to assess the relevance of the instrument to forensic applications. Finally, we present a profile from an automated integrated run where lysed cells from a buccal swab were introduced in the system and no further human intervention was required to complete the analysis.

The effect of propanetriol on the electrochemical properties of nanofumed silica gel of Valve-regulated lead-acid (VRLA) batteries have been investigated by means of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), transmission electron microscope (TEM) and linear sweep voltammetry (LSV). The results show that with the adding of propanetriol the redox peak current density of the lead electrode greatly increases and the reaction resistance reduces obviously. Additionally, the oxygen reactions take place less easily in the gels containing propanetriol. The content of the additive propanetriol also relates with the gel properties. It is proved that the electrochemical properties of gel contained excessive propanetriol (4wt. %) are not as good as that contain 1wt.%~3wt.%.

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Determination of the activity of an enzyme in a solution of nL order was conducted using an electrochemical device with a plug-based microfluidic processing function. β-galactosidase (β-Gal) and adenosine triphosphatase (ATPase) were used as analyte enzymes. β-Gal is often used to be conjugated with antibodies, whereas the latter plays critical roles in cell functions. The activity of the enzymes was determined by measuring the concentration of one of the final products, p-aminophenol (PAP) or hydrogen peroxide (H 2 O 2 ) by coulometry. Preparation of plugs of solutions of predetermined volumes and mixing of solutions was carried out using a Tjunction on the device. A partially shallow flow channel structure was designed in the sensing area to improve collection efficiency. The observed output charge was correlated well with the amount of PAP or H 2 O 2 , which served as an indicator of the enzyme activity.