Capture Chamber Research Articles

Microfluidic-Based Enrichment and Retrieval of Circulating Tumor Cells for RT-PCR Analysis.

Molecular analysis of circulating tumor cells (CTCs) is hindered by low sensitivity and high level of background leukocytes of currently available CTC enrichment technologies. We have developed a novel device to enrich and retrieve CTCs from blood samples by using a microfluidic chip. The Celsee PREP100 device captures CTCs with high sensitivity and allows the captured CTCs to be retrieved for molecular analysis. It uses the microfluidic chip which has approximately 56,320 capture chambers. Based on differences in cell size and deformability, each chamber ensures that small blood escape while larger CTCs of varying sizes are trapped and isolated in the chambers. In this report, we used the Celsee PREP100 to capture cancer cells spiked into normal donor blood samples. We were able to show that the device can capture as low as 10 cells with high reproducibility. The captured CTCs were retrieved from the microfluidic chip. The cell recovery rate of this back-flow procedure is 100% and the level of remaining background leukocytes is very low (about 300-400 cells). RNA from the retrieved cells are extracted and converted to cDNA, and gene expression analysis of selected cancer markers can be carried out by using RT-PCR assays. The sensitive and easy-to-use Celsee PREP100 system represents a promising technology for capturing and molecular characterization of CTCs.

Abstract 1688: Mutation and gene expression analysis of circulating tumor cells (CTCs) enriched and retrieved by a sensitive microfluidic device

Abstract Molecular characterization of CTCs is hindered by low sensitivity and high level of background leukocytes of currently available CTC enrichment devices and assays. We have developed a novel technology to enrich and retrieve CTCs from blood samples using a microfluidic chip. The Celsee PREP100 device captures CTCs with high sensitivity and then allows the captured CTCs to be retrieved for subsequent molecular analysis. The Celsee PREP100 system uses the microfluidic chip which has approximately 56,320 capture chambers. Based on differences in cell size and deformability, each chamber ensures that small blood cells such as red blood cells and most leukocytes escape while larger CTCs are trapped and isolated in the chambers. In the work we used the Celsee PREP100 to capture breast and lung cancer cells spiked into normal donor blood samples, including SKBR3 and NCI-H1975. We were able to show that the device can capture 20 cells with high reproducibility. The captured CTCs were retrieved from the microfluidic chip and further purified with anti-CD45 magnetic beads. Our results suggest that the cell recovery rate of this back-flow procedure is greater than 80% and the level of remaining background leukocytes is very low (about 100 cells). Work in progress to extract DNA and RNA. The resulting DNA samples are subjected to mutation analysis of a panel of cancer markers by using PCR and sequencing. The resulting RNA samples are converted to cDNAs, and gene expression analysis of selected cancer markers are carried out by using RT-QPCR. Specific DNA mutations such as EGFR exon 21 (L585R) in NCI-H1975 and mRNA expression markers including CK-19, TTF1 are tested in the retrieved cells. The sensitive and easy-to-use Celsee PREP100 system represents a promising technology for CTC capturing and molecular characterization. Clinical blood samples from patients with metastatic cancer are being tested on the Celsee PREP100 device and the results will be discussed. Citation Format: Yixin Wang. Mutation and gene expression analysis of circulating tumor cells (CTCs) enriched and retrieved by a sensitive microfluidic device. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1688.

Microfluidic differential immunocapture biochip for specific leukocyte counting.

Enumerating specific cell types from whole blood can be very useful for research and diagnostic purposes-e.g., for counting of CD4 and CD8 T cells in HIV/AIDS diagnostics. We have developed a biosensor based on a differential immunocapture technology to enumerate specific cells in 30 min using 10 μl of blood. This paper provides a comprehensive stepwise protocol to replicate our biosensor for CD4 and CD8 cell counts. The biochip can also be adapted to enumerate other specific cell types such as somatic cells or cells from tissue or liquid biopsies. Capture of other specific cells requires immobilization of their corresponding antibodies within the capture chamber. Therefore, this protocol is useful for research into areas surrounding immunocapture-based biosensor development. The biosensor production requires 24 h, a one-time cell capture optimization takes 6-9 h, and the final cell counting experiment in a laboratory environment requires 30 min to complete.

Experimental studies on the flow characteristics in an inclined bend-free OWC device

A bend-free rectangular cross-section OWC device was designed and constructed for studying the effect of inclination on the flow characteristics inside the device. The inclination is meant to reduce reflection of waves and induce higher velocities in the turbine section. Experimental measurements were made in a wave channel where the OWC device was tested. An S-type Pitot tube was used to measure dynamic pressure of air in the turbine section at several inclinations. Particle Image Velocimetry (PIV) was also done to study the flow of both air and water in the OWC device. In order to focus solely on primary energy capture, no turbine was installed in the OWC device. The dynamic pressure readings were analysed for suction and compression stages. Water volume fluctuations inside the capture chamber were also recorded and compared for different inclinations. The result was an increase in the velocity of air flowing in the capture chamber and hence a rise in the kinetic energy available to the turbine. It was found from experimental studies that as the angle of inclination reduced, the velocity of air in the turbine section increased. The lower angles also caused higher run-up and larger volume of water into the capture chamber.

A two-stage microresistive pulse immunosensor for pathogen detection.

We present a two-stage immunosensor for pathogen detection in a mixed population. In this approach, antibody-conjugated microparticles were used to functionalize the surface of the capture chamber via a convenient magnetic method and a two-stage resistive pulse sensor was used to detect and quantify pathogen cells. We firstly tested the capture efficiency of the functionalized capture chamber. The specific capture efficiency of S. cerevisiae is greater than 94.8%, while the non-specific capture efficiency is 3.4%. We showed that the device can accurately measure pure S. cerevisiae at concentrations ranging from 1.0 to 8.0 × 10(3) cells per μL. We performed S. cerevisiae measurements in a mixture with Chlorella. Both cells have similar sizes. For S. cerevisiae to Chlorella ratios ranging from 1.0 to 2.0, the measurement error was less than 7%, while the error became 20% to 32% for lower ratios ranging from 0.1 to 0.5 caused by nonspecific attachment. We demonstrated that this device is able to isolate target cells and quantitatively measure the cell population in a short time. This device can be potentially used for pathogen detection in the food industry, biological research and clinical applications.

Ultrasensitive microfluidic array for serum pro-inflammatory cytokines and C-reactive protein to assess oral mucositis risk in cancer patients.

In addition to disease diagnostics, there is a need for biomarkers to predict severity of cancer therapy side effects such as oral mucositis. Oral mucositis is an inflammatory lesion of oral mucosa caused by high-dose chemotherapy and/or radiation that is especially prevalent during oral cancer treatment. We describe here a semi-automated, modular microfluidic immunoarray optimized for ultrasensitive detection of pro-inflammatory cytokines involved in pathobiology of oral mucositis. Our goal is to methodologically identify risk of mucositis early in oral cancer treatment, before the onset of lesions. Biomarkers include tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and C-reactive protein (CRP). Protein analytes were captured from serum in a capture chamber by 1-μm magnetic beads coated with antibodies and enzyme labels. Beads are then transported downstream to a detection chamber containing an eight-sensor array coated with glutathione-coated gold nanoparticles (GSH-AuNP) and a second set of antibodies to capture the beads with analyte proteins. In this first application of the immunoarray to four-protein multiplexed measurements, ultralow detection limits of 10-40 fg mL(-1) in 5 μL serum were achieved for simultaneous detection in 30 min. Mass detection limits were 2.5-10 zmol, as few as 1500 molecules. Accuracy and diagnostic utility of the arrays were demonstrated by correlation of levels of the four biomarker proteins in serum from head and neck cancer patients with results from standard ELISA. This approach may lead to rapid, low-cost estimates of projected risk for severity of oral mucositis in cancer patients to enable improved therapeutic management.

Mathematical Modeling of Oscillating Water Columns Wave-Structure Interaction in Ocean Energy Plants

Oscillating Water Column (OWC)-based power take-off systems are one of the potential solutions to the current energy problems arising from the use of nuclear fission and the consumption of fossil fuels. This kind of energy converter turns wave energy into electric power by means of three different stages: firstly wave energy is transformed into pneumatic energy in the OWC chamber, and then a turbine turns it into mechanical energy and finally the turbogenerator module attached to the turbine creates electric power from the rotational mechanical energy. To date, capture chambers have been the least studied part. In this context, this paper presents an analytical model describing the dynamic behavior of the capture chamber, encompassing the wave motion and its interaction with the OWC structure and turbogenerator module. The model is tested for the case of the Mutriku wave power plant by means of experimental results. For this purpose, representative case studies are selected from wave and pressure drop input-output data. The results show an excellent matching rate between the values predicted by the model and the experimental measured data with a small bounded error in all cases, so that the validity of the proposed model is proven.

Automation Highlights from the Literature

Automation Highlights from the Literature

Development of a fluorescence-based sensor for rapid diagnosis of cyanide exposure.

Although commonly known as a highly toxic chemical, cyanide is also an essential reagent for many industrial processes in areas such as mining, electroplating, and synthetic fiber production. The “heavy” use of cyanide in these industries, along with its necessary transportation, increases the possibility of human exposure. Because the onset of cyanide toxicity is fast, a rapid, sensitive, and accurate method for the diagnosis of cyanide exposure is necessary. Therefore, a field sensor for the diagnosis of cyanide exposure was developed based on the reaction of naphthalene dialdehyde, taurine, and cyanide, yielding a fluorescent β-isoindole. An integrated cyanide capture “apparatus”, consisting of sample and cyanide capture chambers, allowed rapid separation of cyanide from blood samples. Rabbit whole blood was added to the sample chamber, acidified, and the HCN gas evolved was actively transferred through a stainless steel channel to the capture chamber containing a basic solution of naphthalene dialdehyde (NDA) and taurine. The overall analysis time (including the addition of the sample) was <3 min, the linear range was 3.13–200 μM, and the limit of detection was 0.78 μM. None of the potential interferents investigated (NaHS, NH4OH, NaSCN, and human serum albumin) produced a signal that could be interpreted as a false positive or a false negative for cyanide exposure. Most importantly, the sensor was 100% accurate in diagnosing cyanide poisoning for acutely exposed rabbits.

The Mark II Bromilow Kinnear humane soft trap: a major upgrade

The Bromilow soft trap was originally created to counter the propensity of black-flanked rock-wallabies (Petrogale lateralis lateralis, hence black-flanked) to harm themselves in wire traps. It achieved that goal commendably and has proven to be durable and versatile as it is also suitable for trapping other medium-sized mammals. Major improvements have been incorporated without altering the basic design thus enabling existing traps to be readily upgraded. The traps are now 15% lighter, and easier to set with a new more reliable trigger. The shroud has been discarded, and it now folds more compactly for transport and storage. The capture chamber is constructed of new materials designed to enable an animal to be extracted more readily. These modifications are described in detail along with illustrations. For anyone intending on building a new trap, free professional-grade architectural drawings of the framework and components are available via the web (see text).

On-line protein capture on magnetic beads for ultrasensitive microfluidic immunoassays of cancer biomarkers

Accurate, sensitive, multiplexed detection of biomarker proteins holds significant promise for personalized cancer diagnostics. Here we describe the incorporation of a novel on-line chamber to capture cancer biomarker proteins on magnetic beads derivatized with 300,000 enzyme labels and 40,000 antibodies into a modular microfluidic immunoarray. Capture and detection chambers are produced from PDMS on machined molds and do not require lithography. Protein analytes are captured from serum or other biological samples in the stirred capture chamber on the beads held in place magnetically. The beads are subsequently washed free of sample components, and wash solutions sent to waste. Removal of the magnet and valve switching sends the magnetic bead–protein bioconjugates into a detection chamber where they are captured on 8 antibody-decorated gold nanoparticle-film sensors and detected amperometrically. Most steps in the immunoassay including protein capture, washing and measurement are incorporated into the device. In simultaneous assays, the microfluidic system gave ultralow detection limits of 5fgmL−1 for interleukin-6 (IL-6) and 7fgmL−1 for IL-8 in serum. Accuracy was demonstrated by measuring IL-6 and IL-8 in conditioned media from oral cancer cell lines and showing good correlations with standard ELISAs. The on-line capture chamber facilitates rapid, sensitive, repetitive protein separation and measurement in 30min in a semi-automated system adaptable to multiplexed protein detection.

Rotationally controlled magneto-hydrodynamic particle handling for bead-based microfluidic assays

This work presents a novel magnetic actuation scheme for advanced particle handling on our previously introduced, centrifugal microfluidic platform for array-based analysis of individual cells and beads. The conceptually simple actuation is based on the reciprocating motion of an elastomeric membrane featuring an integrated permanent magnet and a stationary magnet aligned along the orbit of a disc-based chamber. This compression chamber is placed at the downstream end of the particle capture chamber to induce centripetally directed, hydrodynamic lift forces on particles trapped in V-shaped geometrical barriers. Towards high frequencies of rotation, the on-disc magnet ceases to follow the rapidly oscillating magnetic field, so that the magnetic actuator is disabled during the initial, sedimentation-based filling of the trap array. At reduced spin speeds, the residence time of the magnetic actuator is sufficient to displace the magnetic actuator, resulting in a flow through the V-cup array that re-distributes, and eventually fully depletes, the previously trapped beads from the array. The same magnetic deflection scheme is also demonstrated to accelerate mixing, e.g. for upstream sample preparation.

Complementary Control of Oscillating Water Column-Based Wave Energy Conversion Plants to Improve the Instantaneous Power Output

In this paper, an oscillating water column-based wave energy conversion plant is modeled and controlled by means of two complementary control strategies in order to improve the conversion of wave energy into electric power. This wave power generation system consists of a capture chamber, a Wells turbine, and an induction generator. The improvement relays on the implementation of a control scheme that combines two different control methods: a rotational speed control and an airflow control implemented by means of a throttle valve in series with the turbine. The use of rotational speed control provides a fast way to react to the abrupt and short changes in the turbine speed, ensuring that the average power of the generator is adequately adjusted according to the incident wave power level. Besides, a throttle-valve is used to control the flow through the turbine so as to increase the amount of energy produced, particularly at the higher incident wave power levels. These two control strategies complement each other, maximizing and improving the quality of supply by controlling and smoothing the generated power for different scenarios of wave oscillations, variations of wave grouping, and changes in the sea state.

Enantiomeric selectivity in behavioural and electrophysiological responses of Aedes aegypti and Culex quinquefasciatus mosquitoes

1-Octen-3-ol is a kairomone for many haematophagous insects including mosquitoes. Numerous studies have examined the effects of racemic 1-octen-3-ol; however, few studies have investigated the role of individual enantiomers in relation to mosquito attraction. In the present study, we investigated the behavioural and electrophysiological responses of two mosquito species, Aedes aegypti and Culex quinquefasciatus, to individual enantiomers and mixtures of 1-octen-3-ol, employing a laboratory Y-tube olfactometer and single sensillum recordings. The olfactory receptor neurons of both Ae. aegypti and Cx. quinquefasciatus had a significantly higher response to the (R)-1-octen-3-ol enantiomer compared to the (S)-1-octen-3-ol enantiomer at 10-9 g μl-1 to 10-6 g μl-1. Behaviourally, Ae. aegypti was more responsive to the (R)-1-octen-3-ol enantiomer, showing an increase in flight activity and relative attraction compared to Cx. quinquefasciatus. The (R)-1-octen-3-ol enantiomer caused an increase in activation for Cx. quinquefasciatus. However, the most notable effect was from an (R:S)-1-octen-3-ol mixture (84:16) that caused significantly more mosquitoes to sustain their flight and reach the capture chambers (demonstrated by a reduced non-sustained flight activity), suggesting that it may have a behaviourally excitatory effect. For Cx. quinquefasciatus, a reduced relative attraction response was also observed for all treatments containing the (R)-1-octen-3-ol enantiomer, either on its own or as part of a mixture, but not with the (S)-1-octen-3-ol enantiomer. This is the first time enantiomeric selectivity has been shown for Ae. aegypti using electrophysiology in vivo. The implications of these results for exploitation in mosquito traps are discussed.

Performance studies on an oscillating water column employing a Savonius rotor

A new oscillating water column (OWC) design is proposed in this study to incorporate a simpler Savonius type turbine. Conventional OWC devices employ a bi-directional turbine such as a Wells or an Impulse turbine to extract energy from the air. The disadvantages of the Wells turbine include its inability to self start and stalling. The Savonius turbine is much cheaper and is an effective option at low Reynolds numbers. In the current rectangular OWC device, unlike the circular OWC, the width of entry of the capture chamber can be increased without being influenced by the diameter at the turbine section. To improve its primary capture efficiency, the front and rear walls of the OWC are inclined to minimize reflection. The Savonius rotor characteristics are studied with respect to the change in frequency of the incoming waves. The rotor rpm is sensitive to wave period and primary conversion efficiency while changes in depth only affect the rotor rpm at lower frequencies. The Savonius rotor shows promising results and can be incorporated into large scale OWC devices to reduce costs of the turbine component of the system.

Nitrogen removal via ammonia volatilization in maturation ponds

A simple apparatus was designed to collect ammonia gas coming out from waste stabilization ponds (WSP). The apparatus has a capture chamber and an absorption system, which were optimized under laboratory conditions prior to being used to assess ammonia volatilization rates in a pilot-scale maturation pond during summer 2005. Under laboratory conditions (water temperature = 17.1 degrees C and pH = 10.1), the average ammonia volatilization rate was 2,517 g NH3-N/ha d and the apparatus absorbed 79% of volatilized ammonia. On site, the mean ammonia volatilization rate was 15 g N/ha d, which corresponds to 3% of the total nitrogen removed (531 g N/ha d) in the maturation pond studied. A net nitrogen mass balance showed that ammonia volatilization was not the most important mechanism involved in either total nitrogen or ammonia removal. Nitrogen fractions (suspended organic nitrogen, soluble organic nitrogen, ammonia, nitrite and nitrate) from the M1 influent and effluent showed that ammonia is removed by biological (mainly algal) uptake and total nitrogen removal by sedimentation of dead algal biomass.

An integrated microfluidic processor for single nucleotide polymorphism-based DNA computing

An integrated microfluidic processor is developed that performs molecular computations using single nucleotide polymorphisms (SNPs) as binary bits. A complete population of fluorescein-labeled DNA "answers" is synthesized containing three distinct polymorphic bases; the identity of each base (A or T) is used to encode the value of a binary bit (TRUE or FALSE). Computation and readout occur by hybridization to complementary capture DNA oligonucleotides bound to magnetic beads in the microfluidic device. Beads are loaded into sixteen capture chambers in the processor and suspended in place by an external magnetic field. Integrated microfluidic valves and pumps circulate the input DNA population through the bead suspensions. In this example, a program consisting of a series of capture/rinse/release steps is executed and the DNA molecules remaining at the end of the computation provide the solution to a three-variable, four-clause Boolean satisfiability problem. The improved capture kinetics, transfer efficiency, and single-base specificity enabled by microfluidics make our processor well-suited for performing larger-scale DNA computations.

Multistage Magnetic Particle Separator II. Classification of Ferromagnetic Particles

ABSTRACTA multistage magnetic particle separator was designed and built. The objective of multistage magnetic separation is the collection of particles in liquid suspension according to their net magnetization. The multistage separator was tested in experiments in which suspensions of an iron-carbon composite paniculate in poly(ethylene glycol) were used as feed and in which particles were collected in up to nine fractions according to magnetophoretic mobility. In these experiments particles were aligned in a cylindrical container at a common distance below the top of the container by magnetic levitation using a horizontal bipolar “elevator” electromagnet. After the electromagnet was switched off particles were further levitated by a cylindrical permanent “capture” magnet into a capture chamber directly above and in fluid contact with the container in which the particulate was aligned. After a selected period of time (1–20 min) the capture chamber containing particles that were levitated into it was sheared away from the sample chamber. This process can be repeated up to 15 times using capture chambers in a rotating plate. By changing the time period and capture magnet strength each successive capture results in the collection of particles having decreasing net magnetization based on susceptibility of the particulate material and volume of magnetic material per particle. The test material used in this study was a ferromagnetic particulate consisting of an iron-carbon microcomposite. The separation of a heterogeneous particulate suspension into nine subcategories was demonstrated.

Microchip bioprocessor for integrated nanovolume sample purification and DNA sequencing.

A microfabricated electrophoretic bioprocessor for integrated DNA sequencing sample desalting, template removal, preconcentration, and CE analysis is presented. A low-viscosity gel capture matrix, containing an acrylamide-copolymerized oligonucleotide complementary to the 20-base sequence directly 3' of the M13-40 universal forward priming site, is introduced into the 60-nL capture chamber. Unpurified DNA sequencing reaction products are electrophoretically driven through the chamber; extension products hybridize to the matrix, while contaminating buffering ions, Cl-, excess primer, and template DNA are unretained. Purification under optimized conditions is complete in only 120 s (binding temperature 50 degrees C, driving voltage 250 V). High-speed, integrated sequencing analysis is accomplished by releasing the gel-purified duplex at 67 degrees C and directly injecting onto a 15.9-cm effective length CE microchannel. Electrophoretic resolution of the sequencing products is complete in 32 min, producing a total of 560 bp with phred quality q > or = 20 (accuracy > or = 99%). This fully integrated nanoliter process decreases the purification time approximately 10-fold and the process volume approximately 100-fold while providing state-of-the-art sequencing results.

Ablation of silicate particles in high-speed continuum and transition flow with application to the collection of interplanetary dust particles

view Abstract Citations (2) References (11) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Ablation of Silicate Particles in High-Speed Continuum and Transition Flow with Application to the Collection of Interplanetary Dust Particles Rulison, Aaron J. ; Flagan, Richard C. ; Ahrens, Thomas J. ; Miller, Wayne F. Abstract The ablative deceleration of spheres in the continuum and slip regimes is studied using spherical 7.1-micron-diam soda-lime glass particles launched from vacuum at about 4500 m/sec speed through a 13-micron-thick plastic film into a capture chamber containing Xe at 0.1 or 0.2 atm pressure and 295 K temperature. The results of SEM examinations of the collected ablated particles showed that the ratio of the ablated-particle radius (Rf) to the initial radius (R0) increased with gas pressure (from Rf/R0 about 0.67 at 0.1 atm, to about 0.88 at 0.2 atm). A model was developed to describe the ablation and deceleration of spheres in high-speed continuum and slip flow. The pressure dependence predicted by the model agreed with experimental results. Publication: The Astrophysical Journal Pub Date: April 1991 DOI: 10.1086/169905 Bibcode: 1991ApJ...371..432R Keywords: Ablation; Dust Collectors; Glass; Interplanetary Dust; Silicates; Transition Flow; Continuum Flow; Electron Microscopy; Molecular Flow; Slip Flow; Spectrum Analysis; Instrumentation and Photography; INTERPLANETARY MEDIUM; LABORATORY SPECTRA full text sources ADS |