Dispersion-enhancing surface treatment of AuNPs for a reduced probe loading and detection limit using t-SPR detection

COVID-19 has shown that a highly specific and rapid diagnostic system is a necessity. A spectral imaging-based surface plasmon resonance (SPRi) platform with an integrated microfluidic biosensor to detect oligonucleotide sequences has been proposed to be a promising alternative for infectious diseas...

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Bibliographic Details
Published in:Analyst (London) 2021-09, Vol.146 (18), p.5584-5591
Main Authors: Yeung, Wing Kiu, Lo, Shu-Cheng, Wang, Sheng-Hann, Wei, Pei-Kuen, Cheng, Ji-Yen
Format: Article
Language:English
Subjects:
Biosensors
Coronaviruses
COVID-19
Density
Diagnostic systems
Gold
Infectious diseases
Medical imaging
Microfluidics
Mutation
Nanoparticles
Polyethylene glycol
Spectra
Surface treatment
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Summary:COVID-19 has shown that a highly specific and rapid diagnostic system is a necessity. A spectral imaging-based surface plasmon resonance (SPRi) platform with an integrated microfluidic biosensor to detect oligonucleotide sequences has been proposed to be a promising alternative for infectious diseases due to its safe and straightforward use. Approaches to reduce the DNA probe loading onto gold nanoparticles with various types of polyethylene glycol (PEG) were explored. Here, we demonstrated the stability of functionalised gold nanoparticles with unmodified PEG whilst lowering the probe loading density. The system was evaluated by performing the detection of a mimicking COVID-19 target sequence, single point-mutation sequence and fully mismatch sequence. Highly specific binding of the mimicking COVID-19 target sequence was observed and analysed by the spectral imaging SPR approach. Our work has demonstrated the potential of a controlled probe density using unmodified PEG as an especially promising functionalisation strategy in SPR spectral imaging assays. A nanoplasmonic platform for oligonucleotide detection is developed. Functionalized unmodified PEG-Au was used as an SPR signal amplifier. The SPR sensor exhibited high sensitivity with a detection limit of 100 aM. The platform was able to detect a single mismatch sequence.
ISSN:0003-2654
1364-5528
DOI:10.1039/d1an00973g