Engineering microscale two-dimensional gold nanoparticle cluster arrays for advanced Raman sensing: An AFM study

Domenici, Fabio; Fasolato, Claudia; Mazzi, E.; Angelis, L. De; Brasili, Francesco; Mura, Francesco; Postorino, P.; Bordi, F.

doi:10.1016/j.colsurfa.2016.03.043

Cited by 20 publications

(18 citation statements)

References 25 publications

(54 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The approach adopted in this work to obtain a SERS enhancement independent on the pH of the solution relies in the self-assembly of the 4MBA-AuNPs in micrometric clusters onto glass slides, as shown in Figure S1B. Such aggregates show a stable plasmonic absorption band in the red spectral region (Fasolato et al, 2014; Domenici et al, 2016). The related SERS enhancement is therefore not affected by a different coupling between plasmonic modes upon aggregation, but only by dimensional scale effects of the cluster size which can be overcome by a normalization procedure respect to the intensity of selected pH-independent bands, as discussed below.…”

Section: Resultsmentioning

confidence: 99%

Exploring the Potentiality of a SERS-Active pH Nano-Biosensor

et al. 2019

View full text Add to dashboard Cite

The merging of the molecular specificity of Raman spectroscopy with the extraordinary optical properties of metallic nanoarchitectures is at the heart of Surface Enhanced Raman Spectroscopy (SERS), which in the last few decades proved its worth as powerful analytical tool with detection limits pushed to the single molecule recognition. Within this frame, SERS-based nanosensors for localized pH measurements have been developed and employed for a wide range of applications. Nevertheless, to improve the performances of such nanosensors, many key issues concerning their assembling, calibration and stability, that could significantly impact on the outcome of the pH measurements, need to be clarified. Here, we report on the detailed characterization of a case study SERS-active pH nanosensor, based on the conjugation of gold nanoparticles with the pH-sensitive molecular probe 4-mercaptobenzoic acid (4MBA). We analyzed and optimized all the aspects of the synthesis procedure and of the operating conditions to preserve the sensor stability and provide the highest responsiveness to pH. Exploiting the dependence of the SERS spectrum on the protonation degree of the carboxylic group at the edge of the 4MBA molecules, we derived a calibration curve for the nanosensor. The extrapolated working point, i.e., the pH value corresponding to the highest sensitivity, falls at pH 5.6, which corresponds to the pKa value of the molecule confined at the nanoparticle surface. A shift of the pKa of 4MBA, observed on the molecules confined at the nanostructured interface respect to the bulk counterpart, unveils the opportunity to assembly a SERS-based pH nanosensor with the ability to select its working point in the sensitivity region of interest, by acting on the nanostructured surface on which the molecular probe is confined. As a proof-of-concept, the nanosensor was successfully employed to measure the extracellular pH of normal and cancer cells, demonstrating the capability to discriminate between them.

show abstract

Section: Resultsmentioning

confidence: 99%

Exploring the Potentiality of a SERS-Active pH Nano-Biosensor

et al. 2019

View full text Add to dashboard Cite

show abstract

“…On top of this, AuNPs provide further antibacterial mechanisms, arising from their versatile optical and photothermal properties [13]. These are determined by the excitation of collective electronic oscillations at the metal surface, namely the localised surface plasmons, whose resonance frequency can be tailored by the nanoparticles size, shape and spatial organisation, as well as by the dielectric properties of the surrounding media [18][19][20]. The efficient conversion of the absorbed light into heat allows for designing photothermal vectors capable to burst bacteria [21].…”

Section: Introductionmentioning

confidence: 99%

Assembling patchy plasmonic nanoparticles with aggregation-dependent antibacterial activity

Brasili

Capocefalo

Palmieri

et al. 2020

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

We realise an antibacterial nanomaterial based on the self-limited assembly of patchy plasmonic colloids, obtained by adsorption of lysozyme to gold nanoparticles. The possibility of selecting the size of the assemblies within several hundred nanometres allows for tuning their optical response in a wide range of frequencies from visible to near infrared. We also demonstrate an aggregation-dependent modulation of the catalytic activity, which results in an enhancement of the antibacterial performances for assemblies of the proper size. The gained overall control on structure, optical properties and biological activity of such nanomaterial paves the way for the development of novel antibacterial nanozymes with promising applications in treating multi drug resistant bacteria.

show abstract

“…Recently, many nanostructure shapes have been fabricated for use as SERS substrates including nanorods [14][15][16], nanostars [17,18], nanoantennas [19], and nanospheres [20]; these have been successfully machined by existing lithography-based technologies. Furthermore, hierarchical substrates have also been fabricated by a combination of lithography [21][22][23][24][25] and selfassembly. Matricardi et al [21] used the template-assisted assembly of gold nanospheres with patterned PDMS molds featuring square array geometries with lattice parameters of 400 to 1600 nm and hole diameters of 230 to 960 nm.…”

Section: Introductionmentioning

confidence: 99%

“…Then 4-acetamidothiophenol at 10 −4 mol/L was detected using this substrate. Domenici et al [22] used electron beam lithography and self-assembly methods to fabricate gold clusters of micrometer size and regular spacing. Subsequently, the detection resolution of 4-acetamidothiophenol was 0.05 g/L using the substrate.…”

Section: Introductionmentioning

confidence: 99%

Label-free highly sensitive probe detection with novel hierarchical SERS substrates fabricated by nanoindentation and chemical reaction methods

Zhang¹,

Jia²,

Yan³

et al. 2019

Beilstein J. Nanotechnol.

View full text Add to dashboard Cite

Nanostructures have been widely employed in surface-enhanced Raman scattering (SERS) substrates. Recently, in order to obtain a higher enhancement factor at a lower detection limit, hierarchical structures, including nanostructures and nanoparticles, appear to be viable SERS substrate candidates. Here we describe a novel method integrating the nanoindentation process and chemical redox reaction to machine a hierarchical SERS substrate. The micro/nanostructures are first formed on a Cu(110) plane and then Ag nanoparticles are generated on the structured copper surface. The effect of the indentation process parameters and the corrosion time in the AgNO 3 solution on the Raman intensities of the SERS substrate with hierarchical structures are experimentally studied. The intensity and distribution of the electric field of single and multiple Ag nanoparticles on the surface of a plane and with multiple micro/nanostructures are studied with COMSOL software. The feasibility of the hierarchical SERS substrate is verified using R6G molecules. Finally, the enhancement factor using malachite green molecules was found to reach 5.089 × 10 9 , which demonstrates

show abstract

Engineering microscale two-dimensional gold nanoparticle cluster arrays for advanced Raman sensing: An AFM study

Cited by 20 publications

References 25 publications

Exploring the Potentiality of a SERS-Active pH Nano-Biosensor

Exploring the Potentiality of a SERS-Active pH Nano-Biosensor

Assembling patchy plasmonic nanoparticles with aggregation-dependent antibacterial activity

Label-free highly sensitive probe detection with novel hierarchical SERS substrates fabricated by nanoindentation and chemical reaction methods

Contact Info

Product

Resources

About