Thermally responsive phospholipid preparations for fluid steering and separation in microfluidics

Xing-wei, WU; Langan, Ted J.; Durney, Brandon C.; Holland, Lisa

doi:10.1002/elps.201200173

Cited by 16 publications

(24 citation statements)

References 17 publications

(24 reference statements)

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“…This approach, previously reported with the enzyme neuraminidase,[24] was possible because nanogel is a fluid with a thermally switchable viscosity. [28, 30] The nanogel was introduced into the capillary as a low viscosity fluid at 19 °C and then held in place by transforming it into a high viscosity material at temperatures ranging from 25 to 35 °C. The surface was passivated with a semi-permanent phospholipid coating, which suppressed the electroosmotic flow.…”

Section: Resultsmentioning

confidence: 99%

Capillary electrophoresis with stationary nanogel zones of galactosidase and Erythrina cristagalli lectin for the determination of β(1–3)-linked galactose in glycans

Holland

Gattu

Crihfield

et al. 2017

Journal of Chromatography A

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A thermally responsive nanogel is used to create stationary zones of enzyme and lectin in a separation capillary. Once patterned in the capillary, analyte is driven through the zone, where it is converted to a specific product if an enzyme is used or captured if a lectin is used. These stationary zones are easily expelled after the analysis and then re-patterned in the capillary. The nanogel is compatible with enzymes and lectins and improves the stability of galactosidase, enabling more cost-effective use of biological reagents that provide insight into glycan structure. A feature of using stationary zones is that the reaction time can be controlled by the length of the zone, the applied field controlling the analyte mobility, or the use of electrophoretic mixing by switching the polarity of the applied voltage while the analyte is located in the zone. The temperature, applied voltage, and length of the stationary zone, which are factors that enhance the performance of the enzyme, are characterized. The combined use of enzymes and lectins in capillary electrophoresis is a new strategy to advance rapid and automated analyses of glycans using nanoliter volumes of enzymes and lectins. The applicability of this use of stationary zones of enzyme and lectin in capillary electrophoresis is demonstrated with the identification of β(1-3)-linked galactose in N-glycan.

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Section: Resultsmentioning

confidence: 99%

Capillary electrophoresis with stationary nanogel zones of galactosidase and Erythrina cristagalli lectin for the determination of β(1–3)-linked galactose in glycans

Holland

Gattu

Crihfield

et al. 2017

Journal of Chromatography A

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“…When the relative amount of long chain lipid increases, the aggregates are transformed from a bilayer disk conformation with a small diameter, to disks with larger diameters and 'ribbons' [19,20]. The temperature also impacts the transformation from nanodisks to nanoribbons and a substantial change in apparent viscosity is observed over a temperature range specific to the preparation [34][35][36]. The morphologies adopted by the matrix were dependent on the ratio of long-to-short chain lipid as well as the temperature of the preparation.…”

Section: The Effect Of Temperature and Composition Factors That Impamentioning

confidence: 99%

Reversible phospholipid nanogels for deoxyribonucleic acid fragment size determinations up to 1500 base pairs and integrated sample stacking

Durney

Bachert

Sloane

et al. 2015

Analytica Chimica Acta

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Phospholipid additives are a cost-effective medium to separate deoxyribonucleic acid (DNA) fragments and possess a thermally-responsive viscosity. This provides a mechanism to easily create and replace a highly viscous nanogel in a narrow bore capillary with only a 10°C change in temperature. Preparations composed of dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) self-assemble, forming structures such as nanodisks and wormlike micelles. Factors that influence the morphology of a particular DMPC-DHPC preparation include the concentration of lipid in solution, the temperature, and the ratio of DMPC and DHPC. It has previously been established that an aqueous solution containing 10% phospholipid with a ratio of [DMPC]/[DHPC]=2.5 separates DNA fragments with nearly single base resolution for DNA fragments up to 500 base pairs in length, but beyond this size the resolution decreases dramatically. A new DMPC-DHPC medium is developed to effectively separate and size DNA fragments up to 1500 base pairs by decreasing the total lipid concentration to 2.5%. A 2.5% phospholipid nanogel generates a resolution of 1% of the DNA fragment size up to 1500 base pairs. This increase in the upper size limit is accomplished using commercially available phospholipids at an even lower material cost than is achieved with the 10% preparation. The separation additive is used to evaluate size markers ranging between 200 and 1500 base pairs in order to distinguish invasive strains of Streptococcus pyogenes and Aspergillus species by harnessing differences in gene sequences of collagen-like proteins in these organisms. For the first time, a reversible stacking gel is integrated in a capillary sieving separation by utilizing the thermally-responsive viscosity of these self-assembled phospholipid preparations. A discontinuous matrix is created that is composed of a cartridge of highly viscous phospholipid assimilated into a separation matrix of low viscosity. DNA sample stacking is facilitated with longer injection times without sacrificing separation efficiency.

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“…These materials are introduced into the capillary at a temperature that generates low viscosity and then converted into a highly viscous separation additive in the capillary by changing the separation temperature. For phospholipid nanogels, the viscosity increases by 2 orders of magnitude when the temperature is increased from 19°C to 30°C and the shear rate is changed (79). This thermal response provides a means to easily fill or expel the sieving material at 19°C.…”

Section: CLmentioning

confidence: 99%

Aspergillus Collagen-Like Genes ( acl ): Identification, Sequence Polymorphism, and Assessment for PCR-Based Pathogen Detection

Tuntevski

Durney

Snyder

et al. 2013

Appl Environ Microbiol

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fThe genus Aspergillus is a burden to public health due to its ubiquitous presence in the environment, its production of allergens, and wide demographic susceptibility among cystic fibrosis, asthmatic, and immunosuppressed patients. Current methods of detection of Aspergillus colonization and infection rely on lengthy morphological characterization or nonstandardized serological assays that are restricted to identifying a fungal etiology. Collagen-like genes have been shown to exhibit species-specific conservation across the noncollagenous regions as well as strain-specific polymorphism in the collagen-like regions. Here we assess the conserved region of the Aspergillus collagen-like (acl) genes and explore the application of PCR amplicon size-based discrimination among the five most common etiologic species of the Aspergillus genus, including Aspergillus fumigatus, A. flavus, A. nidulans, A. niger, and A. terreus. Genetic polymorphism and phylogenetic analysis of the aclF1 gene were additionally examined among the available strains. Furthermore, the applicability of the PCR-based assay to identification of these five species in cultures derived from sputum and bronchoalveolar fluid from 19 clinical samples was explored. Application of capillary electrophoresis on nanogels was additionally demonstrated to improve the discrimination between Aspergillus species. Overall, this study demonstrated that Aspergillus acl genes could be used as PCR targets to discriminate between clinically relevant Aspergillus species. Future studies aim to utilize the detection of Aspergillus acl genes in PCR and microfluidic applications to determine the sensitivity and specificity for the identification of Aspergillus colonization and invasive aspergillosis in immunocompromised subjects.

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Thermally responsive phospholipid preparations for fluid steering and separation in microfluidics

Cited by 16 publications

References 17 publications

Capillary electrophoresis with stationary nanogel zones of galactosidase and Erythrina cristagalli lectin for the determination of β(1–3)-linked galactose in glycans

Capillary electrophoresis with stationary nanogel zones of galactosidase and Erythrina cristagalli lectin for the determination of β(1–3)-linked galactose in glycans

Reversible phospholipid nanogels for deoxyribonucleic acid fragment size determinations up to 1500 base pairs and integrated sample stacking

Aspergillus Collagen-Like Genes ( acl ): Identification, Sequence Polymorphism, and Assessment for PCR-Based Pathogen Detection

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