Rapid and Quantitative Detection of Prostate Specific Antigen with a Quantum Dot Nanobeads-Based Immunochromatography Test Strip

Abstract

Convenient and fast testing using an immunochromatography test strip (ICTS) enables rapid yes/no decisions regarding a disease to be made. However, the fundamental limitations of an ICTS, such as a lack of quantitative and sensitive analysis, severely hampers its application in reliable medical testing for the early detection of cancer. Herein, we overcame these limitations by integrating an ICTS with quantum dot nanobeads (QD nanobeads), which were fabricated by encapsulating QDs within modified poly(tert-butyl acrylate-co-ethyl acrylate-co-methacrylic acid) and served as a robust signal-generating reagent for the ICTS. Prostate specific antigen (PSA) was used as a model analyte to demonstrate the performance of the QD nanobeads-based ICTS platform. Under optimized conditions, the concentration of PSA could be determined within 15 min with high sensitivity and specificity using only 40 μL of sample. The detection limit was enhanced by ∼12-fold compared with that of an ICTS that used QDs encapsulated by commercial 11mercaptoundecanoic acid (QDs@MUA) as the signal-generating reagent. At the same time, the possible clinical utility of this approach was demonstrated by measurements recorded from PSA-positive patient specimens. Our data suggest that the QD nanobeads-based ICTS platform is not only rapid and low-cost but also highly sensitive and specific for use in quantitative pointof-care diagnostics; thus, it holds promise for becoming a part of routine medical testing for the early cancer of detection.

Current and Emerging Technologies for Rapid Detection of Pathogens

“…Furthermore, the fluorescent materials enable lateral flow assay to detect the target quantitatively. Compared with colloid gold, which can only provide qualitative or semiquantitative results, quantitative detection can offer more information [42,51,52]. In particular, quantum dots show unique fluorescence properties, such as high and stable fluorescence signal [53][54][55].…”

An On-Site, Ultra-Sensitive, Quantitative Sensing Method for the Determination of Total Aflatoxin in Peanut and Rice Based on Quantum Dot Nanobeads Strip

“…In order to address these problems, doping or encapsulating the beads as a signal amplification label to gain both good chemical and colloidal stability was effective. For example, Li et al, fabricated a test strip, utilizing quantum dot nanobeads (QDNBs) as probes for prostate specific antigen analysis, finding a LOD (limit of detection) of 12-fold lower than the result obtained by single QDs as fluorescent labels [26]. Although there were similar reporters for ZEA or AFB 1 determination in agro-products [22,27], there remained great challenge for AFT sensing via the encapsulated or doped QD nanobeads.…”

An on-site, ultra-sensitive, quantitative sensing method for the determination of total aflatoxin in peanut and rice based on quantum dot nanobeads strip

“…However, the single QD could not be sensitive due to its longstanding issue of chemical and colloidal instability in physiological environments after the phase-transfer procedure [25,26].In order to address these problems, doping or encapsulating the beads as a signal amplification labelto gain both good chemical and colloidal stability was effective. For example, Li et al fabricated a test strip, utilizingquantum dot nanobeads (QDNBs) as probes for prostate specific antigen analysis, finding a LOD (limit of detection) of 12-fold lower than the result obtained by single QDs as fluorescent labels [27].Although there were similar reporters for ZEA or AFB 1 determination in agro-products [23,28], there remained great challenge for the AFT sensing via the encapsulated or doped QD nanobeads. The reason could be the inevitable matrix effect from complicated agro-product samples which would significantly arouse the background noise and then reduce the sensitivity.…”