Seedless gold nanostars with seed-like advantages for biosensing applications

Phiri, Masauso Moses; Mulder, Danielle Wingrove; Vorster, Barend Christiaan

doi:10.1098/rsos.181971

Cited by 41 publications

(24 citation statements)

References 27 publications

(57 reference statements)

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“…A recently published method for the synthesis of seedless silver nitrate and ascorbic acid-assisted AuNSs by Phiri et al . [32] was followed. Briefly, 10 ml of ddH 2 O was acidified with 10 µl of 1 M HCl.…”

Section: Methodsmentioning

confidence: 99%

Facile immobilization of glucose oxidase onto gold nanostars with enhanced binding affinity and optimal function

et al. 2019

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Gold nanoparticles provide a user-friendly and efficient surface for immobilization of enzymes and proteins. In this paper, we present a novel approach for enzyme bioconjugation to gold nanostars (AuNSs). AuNSs were modified with l -cysteine (Cys) and covalently bound to N -hydroxysulfosuccinimide (sulfo-NHS) activated intermediate glucose oxidase (GOx) to fabricate a stable and sensitive AuNSs–Cys–GOx bioconjugate complex. Such a strategy has the potential for increased attachment affinity without protein adsorption onto the AuNSs surface. Good dispersity in buffer suspension was observed, as well as stability in high ionic environments. Using the AuNSs–Cys–GOx bioconjugates showed greater sensitivity in the measuring of low concentrations of glucose based on plasmonic and colorimetric detection. Such a novel approach for enzyme immobilization can lead to AuNSs–Cys–GOx bioconjugate complexes that can be used as catalytic nanodevices in nanobiosensors based on oxidases in biomedical applications.

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Section: Methodsmentioning

confidence: 99%

Facile immobilization of glucose oxidase onto gold nanostars with enhanced binding affinity and optimal function

et al. 2019

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“…Synthesis of the PVP-stabilised seedless AuNSs and subsequent GOx bioconjugation were done using recently published methods by Phiri et al [53,54]. Briefly, 10 mL of ddH 2 O was acidified with 10 µL of 1 M HCl followed by the addition of 50 µL of 100 mM ascorbic acid under mild stirring.…”

Section: Methodsmentioning

confidence: 99%

“…( C ) 1 H-NMR spectra of (I) cysteine-modified AuNSs, and GOx-modified AuNSs using cysteine and N -(3-Dimethylaminopropyl)- N ′-ethylcarbodiimide hydrochloride (EDC)/sulfo-NHS for bioconjugation. (The images were adapted and used with permission from Phiri et al [53]).…”

Section: Figures Scheme and Tablesmentioning

confidence: 99%

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Plasmonic Detection of Glucose in Serum Based on Biocatalytic Shape-Altering of Gold Nanostars

2019

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Nanoparticles have been used as signal transducers for optical readouts in biosensors. Optical approaches are cost-effective with easy readout formats for clinical diagnosis. We present a glucose biosensor based on the biocatalytic shape-altering of gold nanostars via silver deposition. Improved sensitivity was observed due to the nanostars clustering after being functionalised with glucose oxidase (GOx). The biosensor quantified glucose in the serum samples with a 1:1000 dilution factor, and colorimetrically distinguished between the concentrations. The assay demonstrated good specificity and sensitivity. The fabricated glucose biosensor is a rapid kinetic assay using a basic entry level laboratory spectrophotometric microplate reader. Such a biosensor could be very useful in resource-constrained regions without state-of-the-art laboratory equipment. Furthermore, naked eye detection of glucose makes this a suitable biosensor for technology transfer to other point-of-care devices.

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“…[ 13 ] In 2007, a seedless synthetic route was developed based on the directing and reducing capabilities of Good's buffers. [ 17 ] Along the past 5 years, nanosystems based on the superb optical properties of AuNS and related structures have been widely used, examples including photothermal therapy, [ 18–20 ] photoacoustic imaging, [ 21 ] in vivo drug delivery, [ 22,23 ] SERS probes [ 24 ] and biosensing, [ 25,26 ] cancer detection [ 27 ] and imaging, [ 19,28,29 ] among others. [ 1 ] In particular, AuNS can be an excellent tool for ultrasensitive detection of molecular species in low concentration or complex matrices, which constitutes a common need for many areas of human activity such as health, diagnosis, clinical treatment, biology, biochemistry, and environmental chemistry.…”

Section: Introductionmentioning

confidence: 99%

Porphyrin‐conjugated silver‐coated gold nanostars for ultrasensitive detection and multiplexing

Benavides

Moreno

Murgida

et al. 2020

J Raman Spectroscopy

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Here, we propose the use of silver‐coated gold nanostars as the basis for a multiplex sensing system based on surface‐enhanced Raman scattering (SERS)/surface‐enhanced resonance Raman scattering (SERRS) ultrasensitive detection of porphyrins using a 532 nm laser excitation. By modifying the synthetic parameters, we were able to shift the plasmon peak to an optimized position for SERS enhancement of 540 nm for silver‐coated gold nanostars, estimating a SERS enhancement factor around 4.6 × 105. Furthermore, we show high‐resolution transmission electron microscopy (HR‐TEM) images and electron energy‐loss (EEL) spectra of silver‐coated gold nanostars, which provide solid experimental proof on the proposed silver coating mechanism. Finally, we compare the multiplex performance of common reporters such as cyanines and malachite green with the performance of covalently bound porphyrins and show the superiority of the latter. We studied the multiplex detection capabilities of the system with three different porphyrins. By deconvoluting a mixture spectrum into individual porphyrin spectra, we were able to determine the relative concentration of porphyrins with an average error of 3.1%.

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Seedless gold nanostars with seed-like advantages for biosensing applications

Cited by 41 publications

References 27 publications

Facile immobilization of glucose oxidase onto gold nanostars with enhanced binding affinity and optimal function

Facile immobilization of glucose oxidase onto gold nanostars with enhanced binding affinity and optimal function

Plasmonic Detection of Glucose in Serum Based on Biocatalytic Shape-Altering of Gold Nanostars

Porphyrin‐conjugated silver‐coated gold nanostars for ultrasensitive detection and multiplexing

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