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Monitoring cell secretions on microfluidic chips using solid-phase extraction with mass spectrometry.

ABSTRACT: Microfluidics is an enabling technology for both cell biology and chemical analysis. We combine these attributes with a microfluidic device for on-line solid-phase extraction (SPE) and mass spectrometry (MS) analysis of secreted metabolites from living cells in culture on the chip. The device was constructed with polydimethylsiloxane (PDMS) and contains a reversibly sealed chamber for perfusing cells. A multilayer design allowed a series of valves to control an on-chip 7.5 ?L injection loop downstream of the cell chamber with operation similar to a six-port valve. The valve collects sample and then diverts it to a packed SPE bed that was connected in-line to treat samples prior to MS analysis. The valve allows samples to be collected and injected onto the SPE bed while preventing exposure of cells to added back pressure from the SPE bed and organic solvents needed to elute collected chemicals. Here, cultured murine 3T3-L1 adipocytes were loaded into the cell chamber and non-esterified fatty acids (NEFAs) that were secreted by the cells were monitored by SPE-MS at 30 min intervals. The limit of detection for a palmitoleic acid standard was 1.4 ?M. Due to the multiplexed detection capabilities of MS, a variety of NEFAs were detected. Upon stimulation with isoproterenol and forskolin, secretion of select NEFAs was elevated an average of 1.5-fold compared to basal levels. Despite the 30-min delay between sample injections, this device is a step towards a miniaturized system that allows automated monitoring and identification of a variety of molecules in the extracellular environment.

SUBMITTER: Dugan CE

PROVIDER: S-EPMC5203966 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature

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Monitoring cell secretions on microfluidic chips using solid-phase extraction with mass spectrometry.

Dugan Colleen E CE Grinias James P JP Parlee Sebastian D SD El-Azzouny Mahmoud M Evans Charles R CR Kennedy Robert T RT

Analytical and bioanalytical chemistry 20161019 1

Microfluidics is an enabling technology for both cell biology and chemical analysis. We combine these attributes with a microfluidic device for on-line solid-phase extraction (SPE) and mass spectrometry (MS) analysis of secreted metabolites from living cells in culture on the chip. The device was constructed with polydimethylsiloxane (PDMS) and contains a reversibly sealed chamber for perfusing cells. A multilayer design allowed a series of valves to control an on-chip 7.5 μL injection loop down ...[more]

PMID: 27761614

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Project description:Cell-free DNA (cfDNA) is a liquid biopsy marker that can carry signatures (i.e., mutations) associated with certain pathological conditions. Therefore, the extraction of cfDNA from a variety of clinical samples can be an effective and minimally invasive source of markers for disease detection and subsequent management. In the oncological diseases, circulating tumor DNA (ctDNA), a cfDNA sub-class, can carry clinically actionable mutations and coupled with next generation sequencing or other mutation detection methods provide a venue for effective in vitro diagnostics. However, cfDNA mutational analyses require high quality inputs. This necessitates extraction platforms that provide high recovery over the entire ctDNA size range (50 ? 150 bp) with minimal interferences (i.e., co-extraction of genomic DNA), and high reproducibility with a simple workflow. Herein, we present a novel microfluidic solid-phase extraction device (?SPE) consisting of a plastic chip that is activated with UV/O3 to generate surface-confined carboxylic acid functionalities for the ?SPE of cfDNA. The ?SPE uses an immobilization buffer (IB) consisting of polyethylene glycol and salts that induce cfDNA condensation onto the activated plastic microfluidic surface. The ?SPE consists of an array of micropillars to increase extraction bed load (scalable to loads >700 ng of cfDNA) and can be produced at low-cost using replication-based techniques. The entire ?SPE can be fabricated in a single molding step negating the need for adding additional extraction supports to the device simplifying production and keeping device and assay cost low. The ?SPE allowed for recoveries >90% of model cfDNA fragments across a range of sizes (100-700 bp) and even the ability to extract efficiently short cfDNA fragments (50 bp, >70%). In addition, the composition of the IB allowed for reducing the interference of co-extracted genomic DNA. We demonstrated the clinical utility of the ?SPE by quantifying the levels of cfDNA in healthy donors and patients with non-small-cell lung and colorectal cancers. ?SPE extracted cfDNA from plasma samples was also subjected to a ligase detection reaction (LDR) for determining the presence of mutations in the KRAS gene for colorectal and non-small cell lung cancer patients.

Dataset Information

Monitoring cell secretions on microfluidic chips using solid-phase extraction with mass spectrometry.

Publications

Monitoring cell secretions on microfluidic chips using solid-phase extraction with mass spectrometry.

Similar Datasets

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