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An Aqueous Two-Phase System for the Concentration and Extraction of Proteins from the Interface for Detection Using the Lateral-Flow Immunoassay.
PLoS One. 2015; 10(11):e0142654.Plos

Abstract

The paper-based immunoassay for point-of-care diagnostics is widely used due to its low cost and portability over traditional lab-based assays. Lateral-flow immunoassay (LFA) is the most well-established paper-based assay since it is rapid and easy to use. However, the disadvantage of LFA is its lack of sensitivity in some cases where a large sample volume is required, limiting its use as a diagnostic tool. To improve the sensitivity of LFA, we previously reported on the concentration of analytes into one of the two bulk phases of an aqueous two-phase system (ATPS) prior to detection. In this study, we preserved the advantages of LFA while significantly improving upon our previous proof-of-concept studies by employing a novel approach of concentrating gold nanoparticles, a common LFA colorimetric indicator. By conjugating specific antibodies and polymers to the surfaces of the particles, these gold nanoprobes (GNPs) were able to capture target proteins in the sample and subsequently be concentrated within 10 min at the interface of an ATPS solution comprised of polyethylene glycol, potassium phosphate, and phosphate-buffered saline. These GNPs were then extracted and applied directly to LFA. By combining this prior ATPS interface extraction with LFA, the detection limit of LFA for a model protein was improved by 100-fold from 1 ng/μL to 0.01 ng/μL. Additionally, we examined the behavior of the ATPS system in fetal bovine serum and synthetic urine to more closely approach real-world applications. Despite using more complex matrices, ATPS interface extraction still improved the detection limit by 100-fold within 15 to 25 min, demonstrating the system's potential to be applied to patient samples.

Authors+Show Affiliations

Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, United States of America.Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, United States of America.Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, United States of America.Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, United States of America. Division of Advanced Prosthodontics & Weintraub Center for Reconstructive Biotechnology, UCLA School of Dentistry, Los Angeles, California, United States of America.Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, United States of America.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

26556593

Citation

Chiu, Ricky Y T., et al. "An Aqueous Two-Phase System for the Concentration and Extraction of Proteins From the Interface for Detection Using the Lateral-Flow Immunoassay." PloS One, vol. 10, no. 11, 2015, pp. e0142654.
Chiu RY, Thach AV, Wu CM, et al. An Aqueous Two-Phase System for the Concentration and Extraction of Proteins from the Interface for Detection Using the Lateral-Flow Immunoassay. PLoS ONE. 2015;10(11):e0142654.
Chiu, R. Y., Thach, A. V., Wu, C. M., Wu, B. M., & Kamei, D. T. (2015). An Aqueous Two-Phase System for the Concentration and Extraction of Proteins from the Interface for Detection Using the Lateral-Flow Immunoassay. PloS One, 10(11), e0142654. https://doi.org/10.1371/journal.pone.0142654
Chiu RY, et al. An Aqueous Two-Phase System for the Concentration and Extraction of Proteins From the Interface for Detection Using the Lateral-Flow Immunoassay. PLoS ONE. 2015;10(11):e0142654. PubMed PMID: 26556593.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - An Aqueous Two-Phase System for the Concentration and Extraction of Proteins from the Interface for Detection Using the Lateral-Flow Immunoassay. AU - Chiu,Ricky Y T, AU - Thach,Alison V, AU - Wu,Chloe M, AU - Wu,Benjamin M, AU - Kamei,Daniel T, Y1 - 2015/11/10/ PY - 2015/01/16/received PY - 2015/10/26/accepted PY - 2015/11/12/entrez PY - 2015/11/12/pubmed PY - 2016/6/17/medline SP - e0142654 EP - e0142654 JF - PloS one JO - PLoS ONE VL - 10 IS - 11 N2 - The paper-based immunoassay for point-of-care diagnostics is widely used due to its low cost and portability over traditional lab-based assays. Lateral-flow immunoassay (LFA) is the most well-established paper-based assay since it is rapid and easy to use. However, the disadvantage of LFA is its lack of sensitivity in some cases where a large sample volume is required, limiting its use as a diagnostic tool. To improve the sensitivity of LFA, we previously reported on the concentration of analytes into one of the two bulk phases of an aqueous two-phase system (ATPS) prior to detection. In this study, we preserved the advantages of LFA while significantly improving upon our previous proof-of-concept studies by employing a novel approach of concentrating gold nanoparticles, a common LFA colorimetric indicator. By conjugating specific antibodies and polymers to the surfaces of the particles, these gold nanoprobes (GNPs) were able to capture target proteins in the sample and subsequently be concentrated within 10 min at the interface of an ATPS solution comprised of polyethylene glycol, potassium phosphate, and phosphate-buffered saline. These GNPs were then extracted and applied directly to LFA. By combining this prior ATPS interface extraction with LFA, the detection limit of LFA for a model protein was improved by 100-fold from 1 ng/μL to 0.01 ng/μL. Additionally, we examined the behavior of the ATPS system in fetal bovine serum and synthetic urine to more closely approach real-world applications. Despite using more complex matrices, ATPS interface extraction still improved the detection limit by 100-fold within 15 to 25 min, demonstrating the system's potential to be applied to patient samples. SN - 1932-6203 UR - https://www.unboundmedicine.com/medline/citation/26556593/An_Aqueous_Two_Phase_System_for_the_Concentration_and_Extraction_of_Proteins_from_the_Interface_for_Detection_Using_the_Lateral_Flow_Immunoassay_ L2 - http://dx.plos.org/10.1371/journal.pone.0142654 DB - PRIME DP - Unbound Medicine ER -