The construction and clinical application of a surface-enhanced Raman scattering (SERS) platform for the early diagnosis of lung cancer could improve the survival rate of patients and would be of ...great significance. Nevertheless, a sensitive and reusable method for the detection of aldehydes, as biomarkers of lung cancer, in exhaled breath is still an enormous challenge. Aldehydes generally have a low cross section in Raman scattering and have a weak specific affinity to plasmonic nanoparticle surfaces, meaning that sensing them at low concentrations is incredibly difficult. Herein, an ultrasensitive SERS strategy, that can be recycled for further use, for the detection of lung cancer biomarkers in the form of aldehydes was realized by fabrication of a multifunctional Ag NPs@ZIF-67/g-C
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solid phase extraction (SPE) membrane. Based on the change in the vibrational fingerprints of 4-ATP before and after reaction with the aldehydes, the SPE membrane was successfully used for the ultrasensitive detection of aldehydes with a detection limit of 1.35 nM. The excellent SERS performance was attributed to the synergistic effect of the densely and closely distributed Ag NPs (providing SERS "hot spots"), ZIF-67 (concentrating the analyte molecules) and g-C
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(forming a membrane to prolong the contact time between the aldehydes and the substrate). In addition, recycling of the SPE membrane was achieved by utilizing the self-cleaning ability of the Ag NPs@ZIF-67/g-C
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membrane originating from the photocatalytic properties of g-C
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. The proposed SERS membrane was easy to operate, rapid and portable, thus providing a potential tool for a point-of-care test in clinical and diagnostic practice.
An ultrasensitive and portable SERS platform was developed for detecting aldehydes as lung cancer biomarkers based on a multifunctional SPE membrane.
A disposable surface-enhanced Raman scattering (SERS) substrate was prepared by successively spraying silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) onto commercial filter paper using an ...inexpensive consumer sprayer. The strong surface enhancement of AgNPs and chemical stability of AuNPs can be advantageously combined. The substrate exhibited excellent SERS activity for malachite green (MG), methylene blue (MB), and crystal violet (CV) under 785-nm excitation, with limits of detection (LODs) of 4.3 × 10
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, 2.0 × 10
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, and 8.1 × 10
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M, respectively. The substrate exhibited long-term stability, and it can be stored under ambient conditions for 4 weeks with a relative standard deviation of less than 3% among peak intensities. The substrate also showed good reproducibility with a relative standard deviation of 7.1% among different substrate peak intensities. The substrates enable on-site determination of residual fishery drugs and distinguish MG, MB, and CV mixtures in spiked fish within 5 min, and the average recoveries in fish scales and fish meat were better 90.1% and 76.9%, respectively. The method exhibited rapidity, simplicity, and high sensitivity and is expected to be used for the screening of additives in food.
We describe the preparation of a cotton swab for use in surface enhanced Raman scattering (SERS) by assembling silver nanoparticles (Ag-NPs) on common cotton. The flexibility of such cotton swabs ...allows for a close contact with sample surfaces by swabbing. This can considerably improve the sample collection efficiency. These cotton swabs exhibit excellent SERS activity as shown by the detection of rhodamine 6G at 0.81 pM concentration. The reproducibility of the intensity of SERS peaks is within 10 %. The applicability is demonstrated by in-situ detection of the fungicide carbaryl on a cucumber with an irregular surface. This combination of superior SERS activity, high reproducibility, accessibility in irregularly-shaped matrices and low-cost production indicates that such swabs offer a large potential in analytical SERS.
Graphical Abstract
A cost-effective surface enhanced Raman scattering (SERS) cotton swab is developed by assembling silver nanoparticles on common cotton. The SERS cotton swab can be used for in-situ sensitive detection of pesticide residue.
Hydrogen sulfide (H2S) has emerged as an important gasotransmitter in diverse physiological processes, although many aspects of its roles remain unclear, partly owing to a lack of robust analytical ...methods. Herein we report a novel surface‐enhanced Raman scattering (SERS) nanosensor, 4‐acetamidobenzenesulfonyl azide‐functionalized gold nanoparticles (AuNPs/4‐AA), for detecting the endogenous H2S in living cells. The detection is accomplished with SERS spectrum changes of AuNPs/4‐AA resulting from the reaction of H2S with 4‐AA on AuNPs. The SERS nanosensor exhibits high selectivity toward H2S. Furthermore, AuNPs/4‐AA responds to H2S within 1 min with a 0.1 μM level of sensitivity. In particular, our SERS method can be utilized to monitor the endogenous H2S generated in living glioma cells, demonstrating its great promise in studies of pathophysiological pathways involving H2S.
Rapid, selective, and sensitive: The endogenous H2S in living cells can be detected rapidly, selectively, and sensitively using a surface‐enhanced Raman scattering (SERS) nanosensor, 4‐acetamidobenzenesulfonyl azide‐functionalized gold nanoparticles (AuNPs/4‐AA). Based on the rapid and specific reaction between H2S and 4‐AA, combined with the sensitive fingerprinting capability of SERS, the nanosensor can monitor the endogenous H2S generated in a variety of pathophysiological pathways.
The increasing pollution of aquatic environments by antibiotics makes it necessary to develop efficient enrichment and sensitive detection methods for environmental antibiotics monitoring. In this ...work, silver nanoparticles and carbon nanotube-intercalated graphene oxide laminar membranes (Ag NPs/CNT-GO membranes) were successfully prepared for enrichment and surface-enhanced Raman scattering (SERS) detection of antibiotics. The prepared Ag NPs/CNT-GO membranes exhibited a high enrichment ability because of the π–π stacking and electrostatic interactions of GO toward antibiotic molecules, which enhanced the sensitivity of SERS measurements and enabled the antibiotics to be determined at sub-nM concentrations. In addition, the nanochannels created by the intercalation of CNTs into GO layers resulted in an 8-fold enhancement in the water permeance of Ag NPs/CNT-GO membranes compared to that of pure GO membranes. More importantly, the Ag NPs/CNT-GO membranes exhibited high reproducibility and long-term stability. The spot-to-spot variation in SERS intensity was less than 15%, and the SERS performance was maintained for at least 70 days. The Ag NPs/CNT-GO membranes were also used for SERS detection of antibiotics in real samples; the results showed that the characteristic peaks of antibiotics were obviously recognizable. Thus, the sensitive SERS detection of antibiotics based on Ag NPs/CNT-GO offers great potential for practical applications in environmental analysis.
A novel facile method of fabricating disposable and highly reproducible surface-enhanced Raman spectroscopy (SERS) arrays using screen printing was explored. The screen printing ink containing silver ...nanoparticles was prepared and printed on supporting materials by a screen printing process to fabricate SERS arrays (6 × 10 printed spots) in large batches. The fabrication conditions, SERS performance and application of these arrays were systematically investigated, and a detection limit of 1.6 × 10(-13) M for rhodamine 6G could be achieved. Moreover, the screen printed SERS arrays exhibited high reproducibility and stability, the spot-to-spot SERS signals showed that the intensity variation was less than 10% and SERS performance could be maintained over 12 weeks. Portable high-throughput analysis of biological samples was accomplished using these disposable screen printed SERS arrays.
A disposable Ag–graphene sensor was developed for rapid and sensitive in-situ detection of polar antibiotics in water using electrophoretic preconcentration (EP) and surface-enhanced Raman ...spectroscopy (SERS). The Ag–graphene sensor was fabricated by depositing Ag–graphene nanocomposites synthesized through a facile one-pot method on the disposable screen-printed electrodes (SPEs) and characterized by transmission electron microscopy (TEM) and atomic force microscopy (AFM). SERS properties and detection applicability of the developed sensor were systematically investigated. It is shown that the polar antibiotics can be selectively adsorbed on the oppositely charged sensors after applying different potentials during the EP procedure, and the SERS signals of antibiotics with an effective amplification can be achieved with proper time of preconcentration. Moreover, the Ag–graphene sensor could facilitate the molecule adsorption through weak π–π interactions between graphene and antibiotics, further improving the sensitivity of SERS detection. Under the optimum EP conditions, the representative SERS spectra of a mixed solution containing four different antibiotics can be obtained within 10min, and each antibiotic is easily distinguished by its characteristic peaks with a sub-nM detection level. The results demonstrate that the proposed disposable Ag–graphene sensor based on EP–SERS can be used for rapid and sensitive in-situ detection of polar antibiotics in aqueous samples without a pre-separation step.
► We developed Ag–graphene sensors for polar antibiotics detection using EP–SERS. ► EP technique can selectively adsorb antibiotics to the SERS enhancement regions. ► The antibiotics adsorption can be accelerated through weak π–π interactions. ► The proposed method can detect antibiotics of sub-nM level in the mixed solution. ► Rapid and sensitive antibiotics detection can be performed in aqueous.
Determination of hydrogen peroxide (H2O2) with high sensitivity and selectivity in living cells is a challenge for evaluating the diverse roles of H2O2 in the physiological and pathological ...processes. In this work, we present novel surface enhanced Raman scattering (SERS) nanosensors, 4-carboxyphenylboronic acid (4-CA) modified gold nanoparticles (Au NPs/4-CA), for sensing H2O2 in living cells. The nanosensors are based on that the H2O2-triggered oxidation reaction with the arylboronate on Au NPs would liberate the phenol, thus causing changes of the SERS spectra of the nanosensors. The results show the nanosensors feature higher selectivity for H2O2 over other reactive oxygen species, abundant competing cellular thiols and biologically relevant species, as well as excellent sensitivity with a low detection limit of 80nM, which fulfills the requirements for detection of H2O2 in a biological system. In addition, the SERS nanosensors exhibit long term stability against time and pH, and high biocompatibility. More importantly, the presented nanosensors can be successfully used for monitoring changes of H2O2 levels within living biological samples upon oxidative stress, which opens up new opportunities to study its cellular biochemistry.
•We present novel surface enhanced Raman scattering nanosensors for detection of H2O2 in living cells.•The nanosensors feature higher selectivity for H2O2 and show excellent sensitivity with a low detection limit of 80nM.•The nanosensors can be successfully used for monitoring changes of H2O2 levels within biological samples under oxidative stress.
Food-borne pathogens are one of the leading causes of food poisoning, which vigorously affect food safety and human health. Therefore, the development of early and rapid detection methods for food ...pollution evaluation is the key to food safety and quality control. Herein, a simple and inexpensive photoelectrochemical (PEC) sensor is developed for highly selective and ultrasensitive detection of Staphylococcus aureus (S. aureus). The technique is based on “signal-off” that employs Cu–C3N4–TiO2 heterostructures as photoactive materials and monolayer Cu–C3N4 nanozyme as a signal amplifier. In the presence of S. aureus, the aptamer-modified Cu–C3N4 (Cu–C3N4@Apt, a signal amplifier) and S. aureus were specifically anchored on the surface of the ligand-modified photoelectrode. The Cu–C3N4@Apt nanozyme acted as a peroxidase to catalyze the oxidation of 4-chloro-1-naphthol (4-CN) to produce insoluble precipitate on the electrode surface and resulted in a significant decrease in photocurrent. Based on the signal-amplification by the Cu–C3N4@Apt nanozyme, the constructed PEC sensor demonstrated a wide linear range between 10–108 CFU/mL for the S. aureus detection with the detection limit (LOD) as low as 3.40 CFU/mL. Furthermore, the PEC sensor was capable of determining S. aureus in spiked orange juice and milk, with the recovery of 91%–113%, indicating the reliability of the sensor for S. aureus detection in real samples. This investigation provides a feasible strategy for the design of highly selective and ultrasensitive PEC sensors to determine analytes in complex systems.
Trace-element concentrations in acid mine drainage (AMD) are primarily controlled by the mineralogy at the sediment-water interface. Results are presented for a combined geochemical and mineralogical ...survey of Dabaoshan Mine, South China. Developed sequential extraction experiments with the analysis of the main mineralogical phases by semi-quantitative XRD, differential X-ray diffraction (DXRD) and scanning electron microscopy (SEM) were conducted to identify the quantitative relationship between iron minerals and heavy metals. Results showed that schwertmannite, jarosite, goethite and ferrihydrite were the dominant Fe-oxyhydroxide minerals which were detected alternately in the surface sediment with the increasing pH from 2.50 to 6.93 along the Hengshi River. Decreasing contents of schwertmannite ranging from 35 wt % to 6.5 wt % were detected along the Hengshi River, which was corresponding to the decreasing metal contents. The easily reducible fractions exert higher affinity of metals while compared with reducible and relatively stable minerals. A qualitative analysis of heavy metals extracted from the sediments indicated that the retention ability varied: Pb > Mn > Zn > As ≈ Cu > Cr > Cd ≈ Ni. Results in this study are avail for understanding the fate and transport of heavy metals associated with iron minerals and establishing the remediation strategies of AMD systems.
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