Pathogen detection and analysis is critical for medicine, food safety, agriculture, public health and biosecurity. Many current microbial detection approaches are based on century-old culturing methods which, while reliable, are slow, provide relatively little information about the pathogens and are not adaptable to high throughput operations. Optical biodetection represents a potential alternative. Most ELISA and chromatography systems are based on optical methods that are also used for analysis of molecular interactions, such as DNA hybridization and protein-protein interactions (e.g. microarrays or SPR biosensors). Various optical biosensor platforms have been developed that have many of the characteristics essential for modern pathogen molecular analysis including sensitivity, speed of analysis, multi-channel capability, relative simplicity and low cost. Here we provide several examples of the use of optical biosensor technology for pathogen detection and analysis including high throughput DNA microarray analysis, SPR-based rapid direct detection of bacterial toxins, CCD-based fluorescent activity analysis of microbial toxins and a simple ECL-based CCD detection system. However, while effective for molecular analysis, most of these technologies are not as sensitive as traditional culturing methods for detecting microorganisms. There is a need to combine optical biosensors with traditional methods to speed culture-based detection and to provide more information regarding the pathogens.
We present a biosensing platform that uses spatial electroluminescent (EL) illumination combined with charge-coupled
device (CCD)-based detection for fluorescence measurements. The resulting EL-CCD detector platform was used to
monitor different protease activities with substrates labeled for fluorescence resonance energy transfer (FRET)-based
assays. The first uses a commercial FITC/DABCYL-SNAP-25 peptide substrate to monitor the activity of the light
chain derivative (LcA) of botulinum neurotoxin A, achieving a limit of detection (LOD) of 1.25 nM (62 ng/ml). The
second protease activity assay measured trypsin proteolysis using peptide substrates immobilized onto semiconductor
quantum dot (QD) nanoparticles with a LOD of 6.2 nM trypsin (140 ng/ml). The specific ovomucoid inhibition of
trypsin activity was also monitored. The highlighted studies clearly demonstrate the utility of the EL-CCD detector
platform for monitoring fluorescent-based protease activity assays with potential healthcare applications, including
point-of-care diagnostics.
We present a dual-channel surface plasmon resonance (SPR) biosensor and demonstrate its applicability to detection of foodborne pathogens such as Staphylococcal enterotoxin B (SEB). Experimental results indicate that the SPR biosensor can detect SEB at very low concentrations: 5 ng/ml in pure samples directly, 0.5 ng/ml in both pure samples and in milk using a sandwich assay.
Conference Committee Involvement (11)
Optics and Biophotonics in Low-Resource Settings XI
25 January 2025 | San Francisco, California, United States
Optics and Biophotonics in Low-Resource Settings X
27 January 2024 | San Francisco, California, United States
Optics and Biophotonics in Low-Resource Settings IX
28 January 2023 | San Francisco, California, United States
Optics and Biophotonics in Low-Resource Settings VIII
22 January 2022 | San Francisco, California, United States
Optics and Biophotonics in Low-Resource Settings VII
6 March 2021 | Online Only, California, United States
Optics and Biophotonics in Low-Resource Settings VI
1 February 2020 | San Francisco, California, United States
Optics and Biophotonics in Low-Resource Settings V
2 February 2019 | San Francisco, California, United States
Optics and Biophotonics in Low-Resource Settings IV
27 January 2018 | San Francisco, California, United States
Optics and Biophotonics in Low-Resource Settings III
28 January 2017 | San Francisco, California, United States
Optics and Biophotonics in Low-Resource Settings II
13 February 2016 | San Francisco, California, United States
Optics and Biophotonics in Low-Resource Settings
7 February 2015 | San Francisco, California, United States
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