ANALYST
·
2021
·Vol. 146
·期 9
·3016-3024
·
IF 4.616
Tian Lu,Liping Wang,Yuhong Xia,Yang Jin,Liying Zhang,Shuhu Du
Carcinoembryonic antigens (CEAs) are known as one of the most common tumor markers. Their facile and affordable detection is critical for early diagnosis of malignant tumors, especially in resource-constrained settings. Here, we report a novel multimer-based surface-enhanced Raman scattering (SERS) aptasensor for a specific CEA assay. The aptasensor is fabricated through aptamer-assisted self-assembly of silver-coated gold nanoparticles (Au@Ag NPs), and the self-assembled multimeric structure possesses abundant hot-spots to provide high SERS response. When CEA is introduced, the specific recognition of CEA by aptamers will lead to the disassembly of Au@Ag multimers due to the lack of a bridging aptamer between Au@Ag NPs. As a result, the number of hot-spots in the multimeric system is decreased, and the intensity at 1585 cm−1 of the SERS reporter (4-mercaptobenzoic acid, 4-MBA) on the surface of NPs will also be decreased. The Raman intensity is proportional to the logarithm of the concentration of CEA. The detection sensitivity can be down to the pg mL−1 level. The analytical method only needs a droplet of 2 μL of sample, and the detection time is less than 20 min. The multimer-based SERS aptasensor can be applied in sensitive and inexpensive detection of CEA in serum samples.
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ANALYTICAL CHEMISTRY
·
2021
·
IF 6.986
Muhammad Usman Amin,Ruiyuan Zhang,Lingwei Li,Hongjun You,Jixiang Fang
To achieve ultrasensitive detection of trace targets through solution-based surface-enhanced Raman spectroscopy (SERS), direct adsorption of the target molecules on a SERS-active surface is vital. In this work, cetyltrimethylammonium bromide (CTAB)-capped gold nano-bipyramids (Au BPs) with different aspect ratios (ARs) are prepared and the surface is successfully modified by a simple ligand exchange method. Cysteamine-capped gold nano-bipyramids (cyst-Au BPs) are obtained by means of replacement of CTAB by cysteamine using Au–S covalent bonding and applied in the solution-based SERS detection of different pigment molecules, which always have weak affinity to the gold surface. The hydrogen bonding between the pigment molecule and cysteamine causes the aggregation of Au BPs to generate local electromagnetic field enhancement. The influence of the AR and concentration of Au BPs on SERS properties is investigated. The SERS detection of weak-affinity molecules to an extremely low limit shows that the cyst-Au BPs are highly sensitive compared to CTAB-capped Au BPs. The limit of detection (LOD) of allura red as low as 0.1 ppb and that of sunset yellow as low as 1 ppb show that the proposed strategy has many advantages due to its simplicity and fast and rapid detection for the sensitivity analysis of weak-affinity molecules.
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CELLULOSE
·
2020
·Vol. 28
·期 2
·921-936
·
IF 4.21
Yang Jing,Xu Jiangtao,Bian Xueyan,Pu Yi,Chiu Ka lam,Miao Dagang,Jiang Shouxiang
Surface-enhanced Raman scattering (SERS) is gaining prominence as a rapid and effective detection method. However, this technique is still challenged by reusability and sampling issues, especially on irregular surfaces. To address these obstacles, a flexible SERS substrate is designed in this study by using reduced graphene oxide (rGO) as the active material and cotton fabric as the substrate material. The cotton fabric is first modified with a silicane coupling agent before coating with rGO to enhance the adhesion between the rGO and cotton fabric, which would allow reusability of the substrate. The resultant SERS substrate shows a better performance with an enhancement factor of 8 × 10 3 and a calculated sensitivity of 4.5 × 10 −6 M, as well as excellent signal reproducibility with a relative standard deviation (RSD) of 4.72% and stability with RSD value of 5.47%. Meanwhile, the SERS substrate also demonstrates enhanced reusability, and retains strong Raman signals of the dye molecules even after 40 cycles of detection and washing process. The exceptional SERS performance, enhanced reusability, stability and signal reproducibility, along with other intrinsic advantages, such as low cost, ease of availability, and excellent flexibility, render the obtained SERS substrate in this study a promising product for detection in practical applications.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2020
·
IF 3.232
Zhengdong Shen,Qinzhen Fan,Qian Yu,Rui Wang,Huan Wang,Xianming Kong
This work aims to isolate and detect pesticide (carbendazim) residue in real food samples: orange juice and kale leaves. The combination of on-chip thin layer chromatography (TLC) and surface enhanced Raman scattering (SERS) spectroscopy was used for the separating and detecting of carbendazim (MBC) from the complex food sample. In order to achieve on-site detection of MBC from real food sample, the portable Raman spectrometer was coupled with TLC-SERS. The porous stationary phase composed of diatomite biosilica is beneficial for SERS enhancement and eluent migration. The experiments exhibited that the diatomite chip was suitable for TLC separation and has not shown SERS background and provided excellent separation efficiency, 10 −8 M silver colloids were appropriate for the SERS measurement on TLC chip. The food sample was directly spotted onto the diatomite chip for TLC separation without any pretreatment. The separation and detection process were finished in less than 5 min, the mixture of pyrimethanil , pymetrozine and MBC could be distinguished simultaneously by TLC-SERS at one diatomite chip. The MBC in orange juice and kale were successfully detected, and a limit of detection (LOD) less than 2 ppm could be achieved.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2020
·
IF 7.1
Ying Liu,Shuai Yue,Ya-Ning Wang,Yue Wang,Zhang-Run Xu
A multicolor and surface-enhanced Raman scattering (SERS) dual-mode pH sensing method based on microparticles was proposed, which combined the advantages of high sensitivity of SERS and convenience of colorimetric visualization. Polyethylene glycol diacrylate microgels were fabricated using a T-channel microfluidic chip, and the polyaniline-coated gold nanorods were encapsulated in the microgels. Based on the nano-in-micro particles, pH monitoring within the range of 1.0–12.0 was achieved through multicolor and SERS dual-mode sensing. The protonation and deprotonation of polyaniline led to changes in Raman signal intensity and color of microparticles. The pH changes during cell culture were successfully monitored by SERS quantification and microscopic images of the microparticles. And the microparticles exhibit excellent stability, reversibility, biocompatibility, anti-interference ability and signal enhancement ability. The pH sensing method has a wide pH detection range and is especially suitable for pH monitoring in microsystems and micro-environments.
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CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Yi Li,Lu Yu,Jiansheng Li,Lianjun Wang,Rui Lu
The preparation of surface-enhanced Raman scattering (SERS) substrate with both structural stability and SERS activity under extreme pH conditions faces several problems, including tedious preparation, time consuming processes, high cost, and the need for professional equipment and personnel. Herein, a facile preparation protocol for a large-scale nanoarray film substrate was developed for multi-purpose SERS sensing. Through a simple self-assembly process under specific conditions, well-ordered, highly sensitive, structurally tunable, acid-alkali resistant and disposable “polyamide@Ag” coralloid nanoarrays were fabricated. Due to the dense distribution of AgNPs on the top and side surfaces of the nanoarrays and optimized geometric construction, a large number of controllable Raman “hotspots” formed in the space, resulting in excellent Raman signal uniformity and SERS performance for Rhodamine 6G. To evaluate the potential application of this flexible substrate, it was implemented in the label-free trace determination of folic acid with a limit of detection as low as 5.24 × 10 −12 M. Importantly, the as-prepared polyamide@Ag nanoarrays exhibited high structural stability over a wide pH range from 1.25 to 12.00, which is beneficial for the detection of non-pH-neutral samples. The results demonstrated that this hybrid substrate has broad application prospects in fields as diverse as biosensing and environmental monitoring.
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FOOD CHEMISTRY
·
2020
·
IF 6.306
Long Wu,Weimin Zhang,Chen Liu,Mohamed F. Foda,Yongheng Zhu
In this work, based on the strawberry-like SiO 2 /Ag nanocomposites (SANC) immersed filter paper, a newly surface-enhanced Raman scattering (SERS) substrate was constructed for the detection of acrylamide (AAm) in food products. To construct filter paper-based SANC (F-SANC) SERS substrates, SiO 2 nanoparticles (SNP) were firstly synthesized and acted as carriers. After that, the in-situ preparation of silver nanoparticles (Ag NP) on SNP surface was carried out to form the strawberry-like three-dimensional (3D) structure of SANC. Finally, SANC were entangled into the filter paper to produce nanoarchitecture, thus providing enhanced plasmon resonance between SANC with strong SERS signal. Under the optimized conditions, the method exhibited good performance toward AAm with a vast linear response from 0.1 nM to 50 μM (R = 0.9935), limit of detection (LOD) of 0.02 nM (S/N = 3), and the recoveries of 80.5%~105.6% for practical samples. This strategy showed good robustness in the rapid and sensitive detection of AAm, which could be a promising strategy in food analysis and verification.
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Small
·
2020
·Vol. 16
·期 32
·2002801
·
IF 11.459
Ruipeng Chen,Xin Du,Yujun Cui,Xieyuan Zhang,Qinyu Ge,Jian Dong,Xiangwei Zhao
There is a great demand for the development of detection assays for inflammation infection diagnosis with high throughput and ultrasensitivity. Herein, a vertical flow assay system with functionalized nanoporous anodic aluminum oxide (AAO) as sensing membrane, and encoded core–shell surface enhanced Raman scattering (SERS) nanotags as labels for multiple inflammatory biomarkers detection is presented. A 2 × 2 test array on the porous AAO is developed and modified with multiple capture antibodies to capture inflammatory biomarkers from samples. Due to the high surface area to volume ratio of the AAO membrane, and its influence on plasmonic coupling, the electromagnetic field of the encoded core–shell SERS nanotags is enhanced. Detection limits of 53.4, 4.72, 48.3, and 7.53 fg mL −1 are realized for C reactive protein, interleukin-6, serum amyloid A, and procalcitonin, respectively, with a linear dynamic range spanning at least five orders of magnitude. In addition, the proposed method also shows acceptable accuracy and repeatability for the detection of clinical samples. Therefore, this approach is expected to be a powerful point of care testing tool for disease diagnosis in facility limited areas.
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TALANTA
·
2019
·
IF 4.916
Xiang-Nan He,Ya-Ning Wang,Yue Wang,Zhang-Run Xu
Sialic acid (SA) is a special monosaccharide widely distributed at the termini of sugar chains on the cell surface, and its expression level is closely connected with various biological and pathological processes. Therefore, accurate quantitative detection of SA on cancer cell surface is of great significance for clinical diagnosis and therapy. Here, we developed a whole-surface accessible method of accurate SERS quantification of SA level on a single cell, in which silver nanoparticles functionalized with 4-mercaptophenylboric acid and 4-mercaptobenzenitrile was used as the background-free SERS probe. The cyano group on the nanoprobe showed a unique Raman shift at 2232 cm −1 , where most of the biological samples have no Raman response. Meanwhile, the boronic acid group had high specificity to SA molecules at physiological pH. The expression level of SA can be accurately quantitated on the basis of the C N Raman signal. The average number of expressed SA molecules on the surface of a single HeLa cell was 4.6 × 10 7 . And SERS imaging of a single cell was achieved at 2232 cm −1 without biological interference. We evaluated SA expression level on the surface of different cancer cells and dynamically monitored SA expression under the influence of drugs. The proposed approach is accurate as well as sensitive for background-free quantification of SA on cell surface, which is promising for revealing the relationship between tumors and cell surface glycosylation .
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CELLULOSE
·
2019
·Vol. 27
·期 3
·1483-1495
·
IF 3.917
Xian Li,You Ruiyun,Lu Dechan,Wu Changji,Feng Shangyuan,Lu Yudong
In this study, we developed a simple, inexpensive and easily fabricable paper-based SERS substrate with high sensitivity and reproducibility. The filter paper has natural pleats and small pores that allow the metal nanoparticles to be deposited and arranged on the paper to form large area SERS ‘active sites’. Silver nanoparticles can be embedded and grown on cellulose nanocrystals framework through the in situ reduction to form cellulose nanocrystal–silver (CNC–Ag) composites, which are coated on the filter paper to form composite paper-based substrates. The CNC–Ag composites further filled the pores on the surface of the filter paper and improved the adhesive rate of metal nanoparticles, thus the reproducibility of the SERS sensor has been improved. At the same time, because it has the agglomerating effect on samples, the hydrophobic dodecyl mercaptan covered on paper-based substrates can improve detection limit of analyte. Furthermore, we demonstrate that paper-based SERS substrates can efficiently detect two substances, including phenylethanolamine A and metronidazole. The limits of detection for phenylethanolamine A and metronidazole were found to as low as 5 × 10 −9 M and 2 × 10 −7 M, respectively. The paper-based SERS substrates offer great potential for label-free and on-site detection of trace substances.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2019
·
IF 5.589
Weie Wang,Qinqin Sang,Ming Yang,Juan Du,Libin Yang,Xin Jiang,Xiaoxia Han,Bing Zhao
Herein, a surface-enhanced Raman scattering (SERS) strategy based on semiconducting substrate was exploited for detection of several antibiotic residues both in ultrapure water system and in actual water system. The as-prepared Ag-TiO 2 (Ag synchronously deposited and doped TiO 2 ) nanoparticle SERS-active substrate can achieve high sensitive SERS detection for difloxacin hydrochloride, ciprofloxacin, enrofloxacin, danofloxacin and enoxacin (five widely used quinolone antibiotics) in actual water samples, and the detection limits are as low as 4.36 × 10 −12 , 7.08 × 10 −11 , 3.94 × 10 −11 , 3.16 × 10 −11 and 3.15 × 10 −10 mol/L, respectively. These detection limits are far below the maximum of residue limit (3.01 × 10 −7 mol/L) stipulated by the European Union. And, the desirable quantitative relationships can be obtained in a wide concentration range. The recoveries of five antibiotic residues from spiked actual water samples are found to be more than 80.8% with the relative standard deviations between 2.1% and 4.7%. Even, the proposed SERS method can accurately distinguish every antibiotic species from a mixed antibiotic residue sample with multiple antibiotics. And, Ag-TiO 2 nanoparticles can also serve as an efficient photocatalyst for photocatalytic degradation of these antibiotic residues, which provides a multi-functional platform for synchronous determination and degradation of antibiotic residues in real environment.
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Foods
·
2022
·Vol. 11
·期 21
·3407
·
IF 5.561
Hao Wang,Lu Chen,Min Li,Yongxin She,Chao Zhu,Mengmeng Yan
Avoiding interference and realizing the precise detection of mycotoxins in complex food samples is still an urgent problem for surface-enhanced Raman spectroscopy (SERS) analysis technology. Herein, a highly sensitive and specific aptasensor was developed for the anti-interference detection of Ochratoxin A (OTA). In this aptasensor, 4-[(Trimethylsilyl) ethynyl] aniline was employed as an anti-interference Raman reporter to prove a sharp Raman peak (1998 cm−1) in silent region, which could avoid the interference of food bio-molecules in 600–1800 cm−1. 4-TEAE and OTA-aptamer were assembled on Au NPs to serve as anti-interference SERS probes. Meanwhile, Fe3O4NPs, linked with complementary aptamer (cApts), were applied as capture probes. The specific binding of OTA to aptamer hindered the complementary binding of aptamer and cApt, which inhibited the binding of SERS probes and capture probes. Hence, the Raman responses at 1998 cm−1were negatively correlated with the OTA level. Under the optimum condition, the aptasensor presented a linear response for OTA detection in the range of 0.1–40 nM, with low detection limits of 30 pM. In addition, the aptasensor was successfully applied to quantify OTA in soybean, grape and milk samples. Accordingly, this anti-interference aptasensor could perform specific, sensitive and precise detection of OTA in real samples, and proved a reliable reference strategy for other small-molecules detection in food samples.Keywords:SERS;4-TEAE;aptamer;silent region;OTA;anti-interference
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