Simultaneous and multiplex detection of exosomal microRNAs based on the asymmetric Au@Au@Ag probes with enhanced Raman signal

We report a one-step electrochemical deposition technique to prepare three-dimensional (3D) Ag hierarchical micro/nanostructured film consisting of well-crystallized Ag nanosheets grown on an indium tin oxide (ITO) conductive substrate. The Ag hierarchical micro/nanostructures were fabricated in the mixed solution of AgNO3 and sodium citrate in a constant current system at room temperature. Through reduction of Ag[Formula: see text] electrodeposited on the surface of ITO substrate, nanoparticles were grown to form nanosheets which further combined into 3D sphere-like microstructures. The 3D Ag micro/nanostructures have many sharp edges and nanoscale gaps which can give rise to good Raman-enhanced effect. Due to localized surface plasmon resonance (LSPR) effects, these special Ag micro/nanostructures exhibited good Raman-enhanced performance. Using Rhodamine 6G (R6G) molecules as probe molecule, we studied the influence of excitation wavelength on Raman enhancement. The results showed that the 532[Formula: see text]nm excitation wavelength is the best to obtain the strongest Raman signal and to reduce the influence of other impurity peaks. Using the as-synthesized Ag hierarchical micro/nanostructures, we can detect the 10[Formula: see text][Formula: see text]mol/L R6G aqueous solution, exhibiting great Raman-enhanced effect.

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Rapid uropathogen identification using surface enhanced Raman spectroscopy active filters

Scientific Reports ◽

10.1038/s41598-021-88026-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Simon D. Dryden ◽

Salzitsa Anastasova ◽

Giovanni Satta ◽

Alex J. Thompson ◽

Daniel R. Leff ◽

...

Keyword(s):

Raman Spectroscopy ◽

Bacterial Infections ◽

Surface Enhanced Raman Spectroscopy ◽

Active Filters ◽

Raman Signal ◽

Rapid Diagnostics ◽

Bacterial Classification ◽

Surface Enhanced ◽

Surface Enhanced Raman

AbstractUrinary tract infection is one of the most common bacterial infections leading to increased morbidity, mortality and societal costs. Current diagnostics exacerbate this problem due to an inability to provide timely pathogen identification. Surface enhanced Raman spectroscopy (SERS) has the potential to overcome these issues by providing immediate bacterial classification. To date, achieving accurate classification has required technically complicated processes to capture pathogens, which has precluded the integration of SERS into rapid diagnostics. This work demonstrates that gold-coated membrane filters capture and aggregate bacteria, separating them from urine, while also providing Raman signal enhancement. An optimal gold coating thickness of 50 nm was demonstrated, and the diagnostic performance of the SERS-active filters was assessed using phantom urine infection samples at clinically relevant concentrations (105 CFU/ml). Infected and uninfected (control) samples were identified with an accuracy of 91.1%. Amongst infected samples only, classification of three bacteria (Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae) was achieved at a rate of 91.6%.

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Evaluation of Immuno-Rolling Circle Amplification for Multiplex Detection and Profiling of Antigen-Specific Antibody Isotypes

Analytical Chemistry ◽

10.1021/acs.analchem.1c00172 ◽

2021 ◽

Vol 93 (15) ◽

pp. 6169-6177

Author(s):

Sara Horta ◽

Felix Neumann ◽

Shu-hao Yeh ◽

Christoffer Mattsson Langseth ◽

Kadri Kangro ◽

...

Keyword(s):

Specific Antibody ◽

Rolling Circle Amplification ◽

Multiplex Detection ◽

Rolling Circle ◽

Antibody Isotypes

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Enhancement of Raman signal by the use of BaTiO3 microspheres

2020 International Conference Laser Optics (ICLO) ◽

10.1109/iclo48556.2020.9285882 ◽

2020 ◽

Author(s):

I. S. Ruzankina ◽

G. Ferrini

Keyword(s):

Raman Signal

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Graphene, an Interesting Nanocarbon Allotrope for Biosensing Applications: Advances, Insights, and Prospects

Biomedical Engineering and Computational Biology ◽

10.1177/1179597220983821 ◽

2021 ◽

Vol 12 ◽

pp. 117959722098382

Author(s):

Farid Menaa ◽

Yazdian Fatemeh ◽

Sandeep K Vashist ◽

Haroon Iqbal ◽

Olga N Sharts ◽

...

Keyword(s):

Cost Effective ◽

Genetic Alterations ◽

Multiplex Detection ◽

Quantitative Characterization ◽

Disease Biomarkers ◽

Qualitative And Quantitative ◽

Sensing Systems ◽

Doped Graphene ◽

Bioanalytical Applications

Graphene, a relatively new two-dimensional (2D) nanomaterial, possesses unique structure (e.g. lighter, harder, and more flexible than steel) and tunable physicochemical (e.g. electronical, optical) properties with potentially wide eco-friendly and cost-effective usage in biosensing. Furthermore, graphene-related nanomaterials (e.g. graphene oxide, doped graphene, carbon nanotubes) have inculcated tremendous interest among scientists and industrials for the development of innovative biosensing platforms, such as arrays, sequencers and other nanooptical/biophotonic sensing systems (e.g. FET, FRET, CRET, GERS). Indeed, combinatorial functionalization approaches are constantly improving the overall properties of graphene, such as its sensitivity, stability, specificity, selectivity, and response for potential bioanalytical applications. These include real-time multiplex detection, tracking, qualitative, and quantitative characterization of molecules (i.e. analytes [H2O2, urea, nitrite, ATP or NADH]; ions [Hg2+, Pb2+, or Cu2+]; biomolecules (DNA, iRNA, peptides, proteins, vitamins or glucose; disease biomarkers such as genetic alterations in BRCA1, p53) and cells (cancer cells, stem cells, bacteria, or viruses). However, there is still a paucity of comparative reports that critically evaluate the relative toxicity of carbon nanoallotropes in humans. This manuscript comprehensively reviews the biosensing applications of graphene and its derivatives (i.e. GO and rGO). Prospects and challenges are also introduced.

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