Comparison of liposome amplification and fluorophor detection in flow-injection immunoanalyses

Lee, Myoyong; Durst, Richard A.; Wong, Rosie B.

doi:10.1016/s0003-2670(97)00448-0

Cited by 20 publications

(9 citation statements)

References 10 publications

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“…While the use of liposomes as model membranes and in drug and gene delivery applications is well appreciated, their encapsulation properties can also be applied to the creation of highly sensitive bioanalytical devices. A 1000-fold signal amplification can be achieved using liposomes filled with fluorescent material as probes. , Signal amplification can also be carried out with nonfluorescent liposomes by dendritic amplification, where networks of specifically linked liposomes are bound to surfaces. These networks can be detected by Faradaic impedance spectroscopy or by microgravimetry, with detection limits as low as 10 -13 M. , Other biosensing applications rely on the release of electrochemical indicators from the core of liposomes − or colorimetric transitions of polydiacetylene amphiphiles in the bilayer .…”

Section: Introductionmentioning

confidence: 99%

Sequence-Specific Binding of DNA to Liposomes Containing Di-Alkyl Peptide Nucleic Acid (PNA) Amphiphiles

Marques

Schneider

2005

Langmuir

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We present a method to covalently attach peptide nucleic acid (PNA) to liposomes by conjugation of PNA peptide to charged amino acids and synthetic di-alkyl lipids ("PNA amphiphile," PNAA) followed by co-extrusion with disteroylphosphatidylcholine (DSPC) and cholesterol. Attachment of four Glu residues and two ethylene oxide spacers to the PNAA was required to confer proper hydration for extrusion and presentation for DNA hybridization. The extent of DNA oligomer binding to 10-mer PNAA liposomes was assessed using capillary zone electrophoresis. Nearly all PNAs on the liposome surface are complexed with a stoichiometric amount of complementary DNA 10-mers after 3-h incubation in pH 8.0 Tris buffer. No binding to PNAA liposomes was observed using DNA 10-mers with a single mismatch. Longer DNA showed a greatly attenuated binding efficiency, likely because of electrostatic repulsion between the PNAA liposome double layer and the DNA backbone. Langmuir isotherms of PNAA:DSPC:chol monolayers indicate miscibility of these components at the compositions used for liposome preparation. PNAA liposomes preserve the high sequence-selectivity of PNAs and emerge as a useful sequence tag for highly sensitive bioanalytical devices.

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Section: Introductionmentioning

confidence: 99%

Sequence-Specific Binding of DNA to Liposomes Containing Di-Alkyl Peptide Nucleic Acid (PNA) Amphiphiles

Marques

Schneider

2005

Langmuir

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“…The least expensive and perhaps the simplest signal amplification scheme has been achieved with liposomes. Liposomes are phospholipid vesicles that entrap hundreds of thousands of marker molecules to provide a large signal amplification and enhanced sensitivity, three orders of magnitude greater than single fluorophore detection [17].…”

Section: Introductionmentioning

confidence: 99%

A microfluidic biosensor based on nucleic acid sequence recognition

Kwakye

Baeumner

2003

Analytical and Bioanalytical Chemistry

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The development of a generic semi-disposable microfluidic biosensor for the highly sensitive detection of pathogens via their nucleic acid sequences is presented in this paper. Disposable microchannels with defined areas for capture and detection of target pathogen RNA sequence were created in polydimethylsiloxane (PDMS) and mounted onto a reusable polymethylmethacrylate (PMMA) stand. Two different DNA probes complementary to unique sequences on the target pathogen RNA serve as the biorecognition elements. For signal generation and amplification, one probe is coupled to dye encapsulated liposomes while the second probe is coupled to superparamagnetic beads for target immobilization. The probes hybridize to target RNA and the liposome-target-bead complex is subsequently captured on a magnet. The amount of liposomes captured correlates directly to the concentration of target sequence and is quantified using a fluorescence microscope. Dengue fever virus serotype 3 sequences and probes were used as a model analyte system to test the sensor. Probe binding and target capture conditions were optimized for sensitivity resulting in a detection limit of as little as 10 amol microL(-1) (10 pmol L(-1)). Future biosensors will be designed to incorporate a mixer and substitute the fluorescence detection with an electrochemical detection technique to provide a truly portable microbiosensor system.

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“…In this method, the sample and each of the reagents were applied to the protein G microcolumn independently. This format has not previously been reported in work with antibodies that have been adsorbed to protein G or protein A supports; however, it has been used with antibodies that have been covalently immobilized to silica or other materials [8–11,45,47–51]. An important advantage of the sequential injection method is that the label and target/sample never come into contact with each other, which minimizes or eliminates any matrix effects the sample may have on the final response due to the label [10,51].…”

Section: Resultsmentioning

confidence: 99%

Use of protein G microcolumns in chromatographic immunoassays: A comparison of competitive binding formats

Pfaunmiller

Anguizola

Milanuk

et al. 2016

Journal of Chromatography B

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Affinity microcolumns containing protein G were used as general platforms for creating chromatographic-based competitive binding immunoassays. Human serum albumin (HSA) was used as a model target for this work and HSA tagged with a near infrared fluorescent dye was utilized as the label. The protein G microcolumns were evaluated for use in several assay formats, including both solution-based and column-based competitive binding immunoassays and simultaneous or sequential injection formats. All of these methods were characterized by using the same amounts of labeled HSA and anti-HSA antibodies per sample, as chosen for the analysis of a protein target in the low-to-mid ng/mL range. The results were used to compare these formats in terms of their response, precision, limits of detection, and analysis time. All these methods gave detection limits in the range of 8–19 ng/mL and precisions ranging from ± 5% to ± 10% when using an injection flow rate of 0.10 mL/min. The column-based sequential injection immunoassay provided the best limit of detection and the greatest change in response at low target concentrations, while the solution-based simultaneous injection method had the broadest linear and dynamic ranges. These results provided valuable guidelines that can be employed to develop and extend the use of protein G microcolumns and these competitive binding formats to other protein biomarkers or biological agents of clinical or pharmaceutical interest.

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Comparison of liposome amplification and fluorophor detection in flow-injection immunoanalyses

Cited by 20 publications

References 10 publications

Sequence-Specific Binding of DNA to Liposomes Containing Di-Alkyl Peptide Nucleic Acid (PNA) Amphiphiles

Sequence-Specific Binding of DNA to Liposomes Containing Di-Alkyl Peptide Nucleic Acid (PNA) Amphiphiles

A microfluidic biosensor based on nucleic acid sequence recognition

Use of protein G microcolumns in chromatographic immunoassays: A comparison of competitive binding formats

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