In this paper we describe a compact fluorescence detection system for on-chip analysis of beads, comprising a low-cost optical HD-DVD pickup. The complete system consists of a fluorescence detection unit, a control unit and a microfluidic chip containing microchannels and optical markers. With these markers the laser beam of the optical pickup can be automatically focused at the centre of the microchannel. With the complete system a two-dimensional fluorescent profile across the channel width can be obtained such that there is no need for hydrodynamic or electrokinetic focusing of the particles in a specific part of the channel. Fluorescent μm sized beads suspended in medium have been detected with the system. Since on both sides of the main beam two additional laser beams at a known distance are generated, also the velocity of individual beads has been determined.
though the DVD pick-up module includes a photodiode, the fluorescence scanner uses a PMT rather than
the built-in photodiode in order to amplify weak fluorescent signals. The optical pick-up module is
also used to detect fluorescent profiles in microfluidic channels . "
[Show abstract][Hide abstract] ABSTRACT: In this study, we propose a new detection method of nanoparticle-enhanced human papillomavirus
genotyping microarrays using a DVD optical pick-up with a photodiode. The HPV genotyping DNA chip
was labeled using Au/Ag core-shell nanoparticles, prepared on a treatment glass substrate. Then, the
bio information of the HPV genotyping target DNA was detected by measuring the difference of the
optical signals between the DNA spots and the background parts for cervical cancer diagnosis.
Moreover the approximate linear relationship between the concentration of the HPV genotyping target
DNA and the optical signal depending on the density of Au/Ag core-shell nanoparticles was obtained
by performing a spot finding algorithm. It is shown that the nanoparticle-labeled HPV genotyping
target DNA can be measured and quantified by collecting the low-cost photodiode signal on the
treatment glass chip, replacing high-cost fluorescence microarray scanners using a photomultiplier
[Show abstract][Hide abstract] ABSTRACT: Within the past years, single-cell analysis has developed into a key topic in cell biology to study cellular functions that are not accessible by investigation of larger cell populations. Engineering approaches aiming to access single cells to extract information about their physiology, phenotype, and genotype at the single-cell level are going manifold ways, meanwhile allowing separation, sorting, culturing, and analysis of individual cells. Based on our earlier research toward inkjet-like printing of single cells, this article presents further characterization results obtained with a fully automated prototype instrument for printing of single living cells in a noncontact inkjet-like manner. The presented technology is based on a transparent microfluidic drop-on-demand dispenser chip coupled with a camera-assisted automatic detection system. Cells inside the chip are detected and classified with this detection system before they are expelled from the nozzle confined in microdroplets, thus enabling a "one cell per droplet" printing mode. To demonstrate the prototype instrument's suitability for biological and biomedical applications, basic experiments such as printing of single-bead and cell arrays as well as deposition and culture of single cells in microwell plates are presented. Printing efficiencies greater than 80% and viability rates about 90% were achieved.
Journal of the Association for Laboratory Automation 12/2013; 18(6):504-18. DOI:10.1177/2211068213497204 · 1.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Surface-enhanced Raman scattering (SERS) can be combined with microfluidics for rapid multiplex analyte screening. Through combination of the high intensity and complex signals provided by SERS with the flow characteristics of microfluidic channels, we engineered a microdevice that is capable of monitoring various analytes from different sources in real time. Detection limits down to the nM range may allow the generation of a new family of devices for remote, real time monitoring of environmental samples such as natural or waste waters and application to the high-throughput screening of multiple samples in healthcare diagnostics.
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