Detection of Protein Analytes via Nanoparticle-Based Bio Bar Code Technology

Abstract

We describe a new format for the recently introduced bio bar code technology, which improves the dose response over 10,000-fold and thereby makes this technique analytically useful. Unlike other ultrasensitive protein detection methods, such as immuno-PCR or immuno-RCA, the bio bar code technique does not employ any enzymes to achieve detection limits in the attomolar range. By sandwiching a target between a magnetic bead and an amplifier nanoparticle, a multiplicity of bar code oligonucleotides are released for each captured target analyte. These surrogate bar code targets are then hybridized to microarrays and detected with silver-amplified gold nanoparticle probes. Using PSA detection as a model, we demonstrate a linear dose response over at least 4 orders of magnitude in both target concentration and concomitant signal and a 1000-fold improvement in detection limit compared to the best ELISA system.

Detection of HIV-1 P24 Gag in Plasma by a Nanoparticle-Based Bio-Barcode-Amplification Method

“…Fluorescence data were recorded in real-time with an ABI Prism 7900 sequence-detection system (Applied Biosystems, Inc., Foster City, CA, USA). For barcode-DNA identification by a chip-based scanometric method, another portion was hybridized to chip-immobilized DNA complementary to the 5′ half of the barcode-DNA sequence to capture the barcode-DNA sequence and dT20 oligonucleotidefunctionalized 15 nm gold nanoparticles were used to label the other 3′ half of the sequence in a sandwich-assay format [22,23]. Chips with hybridized nanoparticle probes were then subjected to silver amplification.…”

“…Technological advances in nanotechnology provide the opportunity to overcome many shortcomings of other diagnostic approaches [22][23][24][25]. The nanoparticle-based bio-barcodeamplification method offers an innovative approach to protein detection.…”

“…This method offers several advantages over existing protein-detection methods [22,23,25]. Unlike the conventional ELISA assay, the target-binding portion of the bio-barcode assay is performed in solution (as opposed to on the flat surface of an ELISA plate).…”

Nanoparticle-based bio-barcode assay redefines “undetectable” PSA and biochemical recurrence after radical prostatectomy

“…The bio-barcode assay (Scheme 1) is an emerging diagnostic tool, based on advances in nanotechnology, used for the enzymefree ultrasensitive detection of various protein and nucleic acid targets (15)(16)(17)(18). In the case of proteins, the bio-barcode assay can be between one and six orders of magnitude more sensitive than conventional ELISA-based assays, depending on target and sample complexity (15)(16)(17)(18).…”

“…In the case of proteins, the bio-barcode assay can be between one and six orders of magnitude more sensitive than conventional ELISA-based assays, depending on target and sample complexity (15)(16)(17)(18). This increase in sensitivity offers the opportunity to monitor existing biomarkers at levels not possible with conventional assays.…”