LabMedica International
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Lab-On-A-Chip Designed to Minimize Preterm Births n the USA, a half million babies are born preterm; worldwide, the number is an estimated 15 million and complications associated with preterm birth are the number one cause of death for children under five, and those who live often face a range of health problems. There presently are no known current biomarker-based diagnostics for preterm births, and doctors typically only pay attention to women who have other clear risk factors. However with the help from a palm-sized plastic rectangle doctors are hoping to minimize the problem of premature deliveries. The chip is designed to predict, with up to 90% accuracy, a woman's risk for a future preterm birth. Scientists at Brigham Young University (Provo, UT, USA; https://byu. edu) have developed a microfluidic device that uses pH-mediated solid phase extraction (SPE) for the enrichment and elution of preterm birth (PTB) biomarkers. Furthermore, this
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SPE module was integrated with microchip electrophoresis for combined enrichment and separation of multiple analytes, including a PTB peptide biomarker (P1). The team used a reversed-phase octyl methacrylate monolith that was polymerized as the SPE medium in polyethylene glycol diacrylate modified cyclic olefin copolymer microfluidic channels. Eluent for pH-mediated SPE of PTB biomarkers on the monolith was optimized using different pH values and ionic concentrations. The scientists obtained a nearly 50-fold enrichment that was observed in single channel SPE devices for a low nanomolar solution of P1, with great elution time reproducibility. The monolith binding capacity was determined to be 400 pg (0.2 pmol). A mixture of a model peptide (FA) and a PTB biomarker (P1) was extracted, eluted, injected, and then separated by microchip electrophoresis in our integrated device with approximately 15-fold enrichment. Adam T. Woolley, PhD, a chem-
istry professor and senior author of the study, said, “Among other benefits, the device is cheap, small and fast: once fully developed, it will help make detecting biomarkers a simple, automated task. Some peg the annual costs associated with preterm birth just in the USA at close to USD 30 billion, so one clear perk of such a screening tool, is economic. More significantly, there are a lot of preterm babies who don't survive: if we could
get them to survive and thrive, it would be a huge gain to society.” The study was published on March 8, 2017, in the journal Electrophoresis. Image: Scientists loading the integrated electrokinetically driven microfluidic device with pH-mediated solid-phase extraction coupled to microchip electrophoresis for preterm birth biomarkers (Photo courtesy of Nate Edwards, Brigham Young University).
CTC Protein Expression Uses Microfluidic Western Blotting irculating tumor cells (CTCs) are rare tumor cells found in the circulatory system of certain cancer patients and the clinical and functional significance of CTCs is still under investigation. Circulating tumor cells have been isolated from the blood of breast cancer patients and, then microscale physics has been used to design a precision test for protein biomarkers, which are indicators of cancer. Scientists at the University of California (Berkeley, CA, USA; www. berkeley.edu) recruited 12 patients with advanced breast cancer and blood was drawn and processed with in five hours after collection. White blood cells were prepared by lysing the red blood cells. Single-cell resolution western blots (scWB) were used to measure a panel of proteins in single CTCs isolated from patients with primary estrogen receptor-positive (ER+) breast cancer. A commercially available microfluidic tool (Vortex Biosciences, Menlo Park, CA, USA; www.vortexbiosciences.com) was used for label-free isolation of circulating cancer cells in both the cell line spiking and cancer patient blood experiments. Flow cytometry analysis
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was performed and cells were analyzed on a Guava flow cytometer (MilliporeSigma, Billerica, MA, USA; www.merckmillipore.com). The scientists found that the precision handling and analysis revealed a capacity to assay sparingly available patient-derived CTCs, a biophysical CTC phenotype more lysis-resistant than breast cancer cell lines. A capacity to report protein expression was demonstrated on a per CTC basis and two statistically distinct glyceraldehyde 3phosphate dehydrogenase (GAPDH) subpopulations within the patient-derived CTCs. By sorting and probing the protein targets, the test is more selective than existing pathology tools. Amy E. Herr, PhD, a professor and senior author of the study said, “Microfluidic design was key in this study. We were able to integrate features needed for each measurement stage into one process. Systems integration allowed us to do every single measurement step very, very quickly while the biomarkers are still concentrated. If not performed exceptionally fast, the cell’s proteins diffuse away and become undetectable.” The study was published on March 23, 2017, in the journal Nature Communications. LabMedica International November/2017
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