Enhancement Factor Research Articles

Aberrant ecotropic viral integration site-1 (EVI-1) and myocyte enhancer factor 2C gene (MEF2C) in adult acute myeloid leukemia are associated with adverse t (9:22) & 11q23 rearrangements.

Acute myeloid leukemia (AML) shows multiple chromosomal translocations & point mutations which can be used to refine risk-adapted therapy in AML patients. Ecotropic viral integration site-1 (EVI-1) & myocyte enhancer factor 2C gene (MEF2C) are key regulatory transcription factors in hematopoiesis and leukemogenesis & both drive immune escape. This prospective study involved 80 adult de novo AML patients recruited from Oncology Center, Mansoura University, between March 2019 and July 2021. The MEF2C and EVI1 expression were measured using a Taqman probe-based qPCR assay. The results revealed that EVI1 and MEF2C expression were significantly elevated in AML patients as compared to control subjects (p = 0.001. 0.007 respectively). Aberrant expressions of EVI1 and MEF2C showed a significant negative correlation with hemoglobin levels (p = 0.034, 0.025 respectively), & bone marrow blasts (p = 0.007, 0.002 respectively). 11q23 translocation was significantly associated with EVI1 and MEF2C (p = 0.004 and 0.02 respectively). Also, t (9;22) was significantly associated with EVI1 and MEF2C (p = 0.01 and 0.03 respectively), higher expression of EVI1 and MEF2C were significantly associated with inferior outcome after induction therapy (p = 0.001 and 0.018 respectively) and shorter overall survival (p = 0.001, 0.014 respectively). In conclusion, EVI1 & MEF2C were significantly expressed in AML cases. EVI1 & MEF2C overexpression were significantly associated with 11q23 rearrangements and t (9;22) and were indicators for poor outcome in adult AML patients; These results could be a step towards personalized therapy in those patients.

Nano-Architected Titania/Gold@GO Nanosheets for Sonocatalytic Degradation of Azo Dyes in Textile Wastewater

Environmental pollution, a huge issue on a global scale, poses serious risks to both human health and the natural environment. There is an urgent need for effective and reliable detection and degradation methods that focus on the evolution of environmental and trace contaminants. Photochemical methods such as surface-enhanced Raman scattering (SERS) and sono-catalytic degradation can be used to accelerate the detection and degradation of toxic dyes. In the present work, a titania/gold/graphene oxide nanocomposite (ATG) was investigated as a potential dual substrate for SERS sensing and sono-catalytic degradation of pollutants. The nanosize distribution (6-12nm) of ATG was determined by a solvothermal route. X-ray diffraction pattern illustrates the anatase phase of the titanium dioxide. Sonocatalytic degradation was envisaged using Raman spectroscopy. The effectiveness of ATG as a sono-catalytic substrate and SERS sensor was first evaluated using commercial dyes, such as malachite green and bismarck brown. Furthermore, research has been conducted on the harmful elements in actual textile effluents (TE). The N=N and C-N bands found in the SERS spectra of TE are useful indicators of the presence of carcinogenic azo-dye impurities. The enhancement factor was achieved to be 5.77×1012with the limit of detection (LOD) as 6.0×10−12M. Additionally, the sono-catalysis of ATG was evaluated for the elimination of these dye pollutants in TE. Following sono-catalysis by ATG, a high degradation rate constant of approximately 8.44 ×10-3/min was noted in TE with 89% of degradation efficiency. The enhanced SERS detection and sono-catalytic degradation of synthetic dyes and actual effluent stem from the combined action of’ plasmonic characteristics of Au NPs, anatase TiO2, and GO's via π-π stacking nature of GO.

High-performance grating-like SERS substrate based on machine learning for ultrasensitive detection of Zexie-Baizhu Decoction

Rapid, universal and accurate identification of chemical composition changes in multi-component traditional Chinese medicine (TCM) decoction is a necessary condition for elucidating the effectiveness and mechanism of pharmacodynamic substances in TCM. In this paper, SERS technology, combined with grating-like SERS substrate and machine learning method, was used to establish an efficient and sensitive method for the detection of TCM decoction. Firstly, the grating-like substrate prepared by magnetron sputtering technology was served as a reliable SERS sensor for the identification of TCM decoction. The enhancement factor (EF) of 4-ATP probe molecules was as high as 1.90×107 and the limit of detection (LOD) was as low as 1×10-10 M. Then, SERS technology combined with support vector machine (SVM), decision tree (DT), Naive Bayes (NB) and other machine learning algorithms were used to classify and identify the three TCM decoctions, and the classification accuracy rate was as high as 97.78%. In summary, it is expected that the proposed method combining SERS and machine learning method will have a high development in the practical application of multi-component analytes in TCM.

Viral gene detection based on multifunctional microspheres and AgNPs coated substrate interface area SERS scheme

Surface-enhanced Raman spectroscopy (SERS) has emerged as an effective method for detecting viral genes in aqueous solutions. However, SERS has a low efficiency and poor reproducibility in multi-component aqueous solutions. Thus, developing a SERS scheme with stable hotspots generation, significant enhancement effects, and efficient viral gene enrichment remains a challenge. This study sought to proposes an enhanced hotspot generation scheme combining multifunctional microspheres and SERS substrates, which can achieve stable enhancement in the interface area. Multifunctional microspheres can be used to selectively enrich target biomolecules in aqueous solutions. Furthermore, simulation results show that these microspheres can synergistically form a stable enhancement area with SERS substrates. Finally, this scheme was used for immunocapture and Raman detection of hemagglutinin 7 (H7) and neuraminidase 9 (N9) specific gene in an aqueous solution containing multiple types of influenza viral genes. The relationship between the characteristic peaks and concentrations was analysed using two-dimensional correlation analysis. Spectral data analysis revealed an exceedingly high linear correlation between the selected characteristic peak intensity and concentrations. The calculation results show that the SERS enhancement factor of the proposed scheme for the H7 and N9 specific gene are 9.23×107 and 1.59×108, respectively. Notably, the detection limit of this scheme was 1 pM. Therefore, this scheme holds the promise to realize the detection of viral genes in heterogeneous, complex, and dynamic aqueous biological samples.

Linear Vibronic Coupling Approach for Surface-Enhanced Raman Scattering: Quantifying the Charge-Transfer Enhancement Mechanism.

The outstanding amplification observed in surface-enhanced Raman scattering (SERS) is due to several enhancement mechanisms, and standing out among them are the plasmonic (PL) and charge-transfer (CT) mechanisms. The theoretical estimation of the enhancement factors of the CT mechanism is challenging because the excited-state coupling between bright plasmons and dark CT states must be properly introduced into the model to obtain reliable intensities. In this work, we aim at simulating electrochemical SERS spectra, considering models of pyridine on silver clusters subjected to an external electric field E⃗ that represents the effect of an electrode potential Vel. The method adopts quantum dynamical propagations of nuclear wavepackets on the coupled PL and CT states described with linear vibronic coupling models parametrized for each E⃗ through a fragment-based maximum-overlap diabatization. By presenting results at different values of E⃗, we show that indeed there is a relation between the population transferred to the CT states and the total scattered intensity. The tuning and detuning processes of the CT states with the bright PLs as a function of the electric field are in good agreement with those observed in experiments. Finally, our estimations for the CT enhancement factors predict values in the order of 105 to 106, meaning that when the CT and PL states are both in resonance with the excitation wavelength, the CT and PL enhancements are comparable, and vibrational bands whose intensity is amplified by different mechanisms can be observed together, in agreement with what was measured by typical experiments on silver electrodes.

Hierarchically porous coralloid ZnO@Ag microspheres as SERS substrate for highly sensitive malachite green detection

The improper management and unreasonable use of malachite green (MG) in aquatic transportation and large-scale aquaculture pose a significant threat to human health. It is crucial to develop a rapid and reliable approach for detecting MG. In this study, hierarchically porous coralloid ZnO@Ag (C–ZnO@Ag) microspheres were developed as a surface-enhanced Raman scattering (SERS) substrate to detect MG content in water. The hierarchical and porous structure supporting plenty of Ag nanoparticles provides numerous “hot spots” to excite the strong enhanced local electromagnetic field for enlarging the Raman signals of analytes. Moreover, C–ZnO@Ag generates an additional pathway to improve the charge transfer between the substrate and analytes. The manifold mechanisms resulted in the Raman enhancement factor as high as 1.61 × 107 when R6G was selected as the probe. The MG solution at an ultralow concentration of 10−9 M can be successfully identified using the C–ZnO@Ag substrate, which is much lower than the maximum MG residual concentration in water set by the European Union. Therefore, the C–ZnO@Ag substrate has promising opportunities to be applied in rapid SERS-based detection of toxic organic residues.

Evolution of flow structure and heat transfer enhancement mechanism in impinging jets excited by piezoelectric fan

While jet impingement is recognized for significantly enhancing local convective heat transfer, there remains a considerable challenge in further improving its heat transfer performance and uniformity to meet the growing demand for efficient heat transfer. To address this challenge, this study proposes a method that integrates a piezoelectric fan into a continuous jet, taking advantage of the piezoelectric fan's vibration to deliver pulsating excitation to jet impingement while preserving its continuity. An experimental study is performed to identify the roles of piezo-fan integration on improving convective heat transfer from a continuous circular jet onto a flat target surface. The tests are performed under Rej=2,500∼7,500 (circular jet), s/d = 2∼28 (non-dimensional fan-to-jet distance) and L/d = 2∼8 (non-dimensional jet-to-target distance). In addition, few numerical simulations regarding the flow fields are also made to illustrate the mutual interaction mechanism between piezo-fan and continuous jet. The findings reveal that, in the longitudinal configuration, the average values of heat transfer enhancement factor (χ) and heat transfer uniformity factor (ξ) are approximately 13% and 0.5% higher, respectively, compared to the transverse configuration. In the longitudinal arrangement, the significance of the piezoelectric fan amplifies as the circular nozzle gradually distances itself from the target surface. This fan assumes a pivotal role in augmenting both the uniformity and efficiency of heat transfer associated with the circular jet. Conversely, when the piezoelectric fan moves beyond a specific s/d value (s/d = 10), the interaction between intermittent flow and the wall-jet experiences complete cessation. Despite the existence of a fountain effect resulting from the interaction between the piezoelectric fan and the circular jet in the longitudinal configuration, its discernible impact on overall heat transfer attenuation is minimal. The insights gained from this study will be valuable in improving active strategies for jet impingement and promoting the development of piezoelectric functional devices.

Silver Dendrite‐Coated Silicon Pyramid Substrate as Surface‐Enhanced Raman Scattering Probe for Detecting Glucose

Raman spectroscopy offers a rapid and nondestructive method for qualitatively and quantitatively analyzing the molecular structure of substances. Herein, a facile and cost‐effective approach for the preparation of three‐dimensional (3D) surface‐enhanced Raman scattering (SERS) substrates is proposed, in which pyramid structures are fabricated using silicon anisotropic wet etching and silver dendrites are decorated on these silicon pyramid (PSi) substrates by immersing them in a mixture of hydrofluoric acid and silver nitrate for several minutes. The 3D SERS substrates, based on PSi coated with Ag dendrites, reveal high‐performance SERS enhancement (with an analytical enhancement factor reaching 3.54 × 1010) and can detect rhodamine 6G (R6G) in the presence of chemical enhancer (lithium chloride) at low concentrations down to 10−11 m. For glucose detection, 2‐thienylboronic acid is employed to faciliate glucose attachment to the substrate surface, achieving a detection limit as low as 10−6 m. The substrate exhibits good repeatability with a relative standard deviation of 11.223%, as well as reusability and long‐term stability for detection. The results also highlight the excellent sensitivity of the PSi‐based SERS substrate, which is expected to be instrumental in biochemical analysis and holds significant potential for developing noninvasive glucose sensor for diabetic patients using saliva samples.

Silicon nitride (Si3N4) leads to enhanced performance of silica-silver based plasmonic sensor for colorectal cancer detection under optimum radiation damping

Silicon Nitride (Si3N4) possesses large refractive index and transparent behaviour in a broad spectral range from ultraviolet to infrared. These properties of Si3N4 facilitate an efficient light-matter interaction leading to enhanced light confinement. In this work, we have investigated Si3N4-based plasmonic sensor for pathogenic colorectal tissues detection at a wavelength of 1000 nm. The sensor structure consists of fused silica prism and Ag–Si3N4 heterojunction. The figure-of-merit (FOM) of the sensor is optimized by judiciously coordinating the thickness of Ag layer (dM) and Si3N4 layer (dA) under optimum radiation damping (ORD). An optimized FOM as high as 6011 RIU−1 (at dM = 47.3 nm) has been achieved corresponding to dA = 8.6 nm under ORD. At ORD, the corresponding power loss ratio (PLR) is as high as 2.773, and the normalized electric field enhancement factor (FEF) is about 1.06. The magnitude of combined performance factor (CPF), which is the product of FOM, PLR and FEF, of the proposed sensor is as large as 17668.61 RIU−1. The proposed application of Si3N4 in plasmonic sensor in combination with ORD condition leads to substantially enhanced sensing performance and has been explored for the first time to the best of our knowledge.

Benchtop Fabricated Nano-Roughened Microstructured Electrodes for Electrochemical and Surface-Enhanced Raman Scattering Sensing.

Tailoring a material's surface with hierarchical structures from the micro- to the nanoscale is key for fabricating highly sensitive detection platforms. To achieve this, the fabrication method should be simple, inexpensive, and yield materials with a high density of surface features. Here, using benchtop fabrication techniques, gold surfaces with hierarchically structured roughness are generated for sensing applications. Hierarchical gold electrodes are prepared on pre-stressed polystyrene substrates via electroless deposition and amperometric pulsing. Electrodes fabricated using 1mm H[AuCl₄] and roughened with 80 pulses revealed the highest electroactive surface area. These electrodes are used for enzyme-free detection of glucose in the presence of bovine serum albumin and achieved a limit of detection of 0.36mm, below glucose concentrations in human blood. The surfaces nanoroughened with 100 pulses also showed excellent surface-enhanced Raman scattering (SERS) response for the detection of rhodamine 6G, with an enhancement factor of ≈2×106 compared to detection in solution, and for the detection of a self-assembled monolayer of thiophenol, with an enhancement factor of ≈30 compared to the response from microstructured gold surfaces. It is envisioned that the simplicity and low fabrication cost of these gold-roughened structures will expedite the development of electrochemical and SERS sensing devices.

Acid-based deep eutectic solvents followed by GFAAS for the speciation of As(III), As(V), total inorganic arsenic and total arsenic in rice samples

In the present study, an efficacious, safe, inexpensive and eco-friendly microextraction was provided by deep eutectic solvents based on dispersive liquid–liquid microextraction (DLLME − DES) followed by GFAAS. A series of DESs were synthesised using l-menthol as hydrogen bond acceptor (HBA) and carboxylic acids with 4, 6, 8 and 10 carbon atoms as hydrogen bond donors (HBD). The synthesised DESs were used as extractants of arsenic ions. Under optimised conditions, good linearity with coefficient of determination (r 2) 0.992 and an acceptable linear range of 0.3–100 µg kg−1 was obtained. The limit of detection was 0.1 µg kg−1 (S/N = 3) for arsenite (As(III)) ions, and a high enrichment factor (EF = 200) was obtained. The enhancement factor and extraction recovery (ER%) of the method were 340 and 60%, respectively. RSDs including inter- and intra-day ranged from 3.2% to 5.8% in three examined concentrations. After a specific digestion, the capability of the synthesised DES in the extraction of As(III) from rice was tested. Total inorganic arsenic was separated similarly after reduction of arsenate (As(V)) to As(III), and As(V) concentration was calculated by difference. Using a second digestion method, total arsenic concentration (sum of organic and inorganic arsenic) in the samples was determined.

MEF2C contributes to axonal branching by regulating Kif2c transcription.

Neurons are post-mitotic cells, with microtubules playing crucial roles in axonal transport and growth. Kinesin family member 2c (KIF2C), a member of the Kinesin-13 family, possesses the ability to depolymerize microtubules and is involved in remodelling the microtubule lattice. Myocyte enhancer factor 2c (MEF2C) was initially identified as a regulator of muscle differentiation but has recently been associated with neurological abnormalities such as severe cognitive impairment, stereotyping, epilepsy and brain malformations when mutated or deleted. However, further investigation is required to determine which target genes MEF2C acts upon to influence neuronal function as a transcription regulator. Our data demonstrate that knockdown of both Mef2c and Kif2c significantly impacts spinal motor neuron development and behaviour in zebrafish. Luciferase reporter assays and chromosome immunoprecipitation assays, along with down/upregulated expression analysis, revealed that MFE2C functions as a novel transcription regulator for the Kif2c gene. Additionally, the knockdown of either Mef2c or Kif2c expression in E18 cortical neurons substantially reduces the number of primary neurites and axonal branches during neuronal development in vitro without affecting neurite length. Finally, depletion of Kif2c eliminated the effects of overexpression of Mef2c on the neurite branching. Based on these findings, we provided novel evidence demonstrating that MEF2C regulates the transcription of the Kif2c gene thereby influencing the axonal branching.

Rapid hydrolysis of NO2 at High Ionic Strengths of Deliquesced Aerosol Particles.

Nitrogen dioxide (NO2) hydrolysis in deliquesced aerosol particles forms nitrous acid and nitrate and thus impacts air quality, climate, and the nitrogen cycle. Traditionally, it is considered to proceed far too slowly in the atmosphere. However, the significance of this process is highly uncertain because kinetic studies have only been made in dilute aqueous solutions but not under high ionic strength conditions of the aerosol particles. Here, we use laboratory experiments, air quality models, and field measurements to examine the effect of the ionic strength on the reaction kinetics of NO2 hydrolysis. We find that high ionic strengths (I) enhance the reaction rate constants (kI) by more than an order of magnitude compared to that at infinite dilution (kI=0), yielding log10(kI/kI=0) = 0.04I or rate enhancement factor = 100.04I. A state-of-the-art air quality model shows that the enhanced NO2 hydrolysis reduces the negative bias in the simulated concentrations of nitrous acid by 28% on average when compared to field observations over the North China Plain. Rapid NO2 hydrolysis also enhances the levels of nitrous acid in other polluted regions such as North India and further promotes atmospheric oxidation capacity. This study highlights the need to evaluate various reaction kinetics of atmospheric aerosols with high ionic strengths.

Investigations on Optical Absorption and the Pyro-phototronic Effect with Selectively Patterned Black Silicon for Advanced Photodetection.

A novel property existing in the stain-etching technique that eliminates the need for expensive etchant masks in the texturization process of silicon wafers was identified. Through the combination of grayscale lithography and stain-etching methodologies, selective patterning of silicon with AR-P 3510 T, a positive-photoresist mask, was carried out. The etch area ratio was varied in nine different patterns of various feature sizes ranging from 400 to 1500 μm. The optical characteristics of the patterned substrates were determined from diffuse reflectance spectroscopy analysis, and the results were supported with finite-difference time-domain simulations. Complimenting the improvement in optical properties, the electrical losses in microwell-patterned photodetector devices have been reduced with an electro-optic optimum value of the surface enhancement factor, γ. The photodetecting efficiency of a selectively patterned microwell photodetector device exceeded the planar and black silicon photodetector devices with a considerable improvement in the pyro-phototronic effect. This work suggests an alternative for black silicon optoelectronic devices providing a new route to fabricate selectively patterned substrates with an achieved detectivity 16- and 20-fold higher than black and planar silicon photodetector devices, respectively.

Electrochemical synthesis of 2D-silver nanodendrites functionalized with cyclodextrin for SERS-based detection of herbicide MCPA

Surface enhanced Raman spectroscopy (SERS) is a powerful analytical technique that has found application in the trace detection of a wide range of contaminants. In this paper, we report on the fabrication of 2D silver nanodendrites, on silicon chips, synthesized by electrochemical reduction of AgNO3 at microelectrodes. The formation of nanodendrites is tentatively explained in terms of electromigration and diffusion of silver ions. Electrochemical characterization suggests that the nanodendrites do not stay electrically connected to the microelectrode. The substrates show SERS activity with an enhancement factor on the order of 106. Density functional theory simulations were carried out to investigate the suitability of the fabricated substrate for pesticide monitoring. These substrates can be functionalized with cyclodextrin macro molecules to help with the detection of molecules with low affinity with silver surfaces. A proof of concept is demonstrated with the detection of the herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA).

Facile interfacial synthesis of gold micronails with adjustable length and roughness and their superior SERS properties for the detection of p-aminothiophenol

Au hierarchical architectures with special morphology and structures are strongly desired in varied applications. Herein, a simple synthesis method was developed for the one-step preparation of Au micronails (MNs) at the planar liquid-liquid interface under mild conditions. The well-defined Au MNs were grown and constructed at CHCl3–H2O interface at room temperature using aniline in CHCl3 as reducing agent and HAuCl4 in H2O as precursor and no surfactant or seed is required. The intriguing Au MNs with rough surface consist of big heads and thin rods, just like iron nails in outline. Furthermore, through simple changing the reagent concentrations, the length and surface roughness of Au MNs can be adjusted conveniently. The effects of a series of factors on the morphology and structure of the products are studied in detail. With p-aminothiophenol as a molecular probe, the as-obtained Au MNs all exhibit dramatically improved surface enhanced Raman scattering sensitivity and high reproducibility, the enhancement factor and limit of detection of Au MNs are 5.4 × 105 and 1.0 × 10−10, respectively.

Ultrasensitive detection of L-phenylalanine on DC magnetron sputtered bismuth thin films using label-free SERS method

Quantitative imbalances in monomers such as amino acids, nucleotides etc. act as biomarkers for various health conditions like cancer, Alzheimer’s, genetic disorders etc. Different atmospheric annealed bismuth (Bi) thin films deposited by DC magnetron sputtering were compared to select a better Surface Enhanced Raman Spectroscopy (SERS) platform. The tailored morphology favoured confining of localized surface plasmon resonance (LSPR) between close-packed Bi nanoparticles. The Multiple SPRs (Mult. SPRs) from interband plasmonic transitions are majorly present in the ultraviolet (UV)-near-visible region making the film a promising UV- SERS platform. The varied annealing’s have tuned the SPR and are supported by the colour changes of Bi films. The Raman modes confirmed the chemical stability the films. XPS etching revealed the metallic state of the optimized Bi-D-PDV2 film. The preliminary SERS applications on Rhodamine 6 G (RH6G) selected a Bi-D-PDV2 film with an enhancement factor (EF) of ∼4 ×105. This optimized film used for L-phenylalanine (Phe) detection, resulted in enhanced sensitivity of ∼2 ×106 EF with a sub-micromolar (0.1 μM) limit of detection (LOD). The ultra-sensitive responses in the sub-μM level from the optimized Bi thin film for standard as well as biomolecule is reported for the first time to the best extent of knowledge. The potential responses from the optimized film gives promising response for its use in ultra-sensitive bio detections even down to single molecular level in future.

Extraordinary Enhancement of Nonlinear Optical Interaction in NbOBr2 Microcavities.

2D materials are burgeoning as promising candidates for investigating nonlinear optical effects due to high nonlinear susceptibilities, broadband optical response, and tunable nonlinearity. However, most 2D materials suffer from poor nonlinear conversion efficiencies, resulting from reduced light-matter interactions and lack of phase matching at atomic thicknesses. Herein, a new 2D nonlinear material, niobium oxide dibromide (NbOBr2) is reported, featuring strong and anisotropic optical nonlinearities with scalable nonlinear intensity. Furthermore, Fabry-Pérot (F-P) microcavities are constructed by coupling NbOBr2 with air holes in silicon. Remarkable enhancement factors of ≈630 times in second harmonic generation (SHG) and 210 times in third harmonic generation (THG) are achieved on cavity at the resonance wavelength of 1500nm. Notably, the cavity enhancement effect exhibits strong anisotropic feature tunable with pump wavelength, owing to the robust optical birefringence of NbOBr2. The ratio of the enhancement factor along the b- and c-axis of NbOBr2 reaches 2.43 and 5.27 for SHG and THG at 1500nm pump, respectively, which leads to an extraordinarily high SHG anisotropic ratio of 17.82 and a 10° rotation of THG polarization. The research presents a feasible and practical strategy for developing high-efficiency and low-power-pumped on-chip nonlinear optical devices with tunable anisotropy.

Eliminating sensing blind spots of field-enhanced Rydberg atomic antenna via an asymmetric parallel-plate resonator

Due to its large electric dipole moment, the Rydberg atom exhibits a strong response to weak electric fields, hence it is regarded as a highly promising atomic antenna. However, to enhance the reception sensitivity, split-ring resonators are needed normally, which will brings sensing blind spots. Thus it is not conducive to the application of full-coverage space communication. Here we propose that an atomic antenna with an asymmetric parallel-plate resonator, can not only enhance the received signal, but also eliminate sensing blind spots (pattern roundness can reach 7.8 dB while the split-ring resonator can be up to 39 dB). We analyze the influence of structural parameters on the field enhancement factor and directionality, and further discuss the limitation of the sensitivity by using thermal resistor noise theory. This work is expected to pave the way for the development of field-enhanced Rydberg atomic antennas that communicate without a blind spot.

Rapid detection of melamine by DNA Walker mediated SERS sensing technique based on signal amplification function.

A new method is proposed for detecting typical melamine dopants in food using surface-enhanced Raman scattering (SERS) biosensing technology. Melamine specific aptamer was used as the identification probe, and gold magnets (AuNPs@MNPs) and small gold nanoparticles (AuNPs@MBA) were used as the basis for Raman detection. The Raman signal of the detection system can directly detect melamine quantitatively. Under optimized conditions, the detection of melamine was carried out in the low concentration range of 0.001-500mg/kg, the enhancement factor (EF) was 2.3 × 107, and the detection limit was 0.001mg/kg. The method is sensitive and rapid, and can be used for the rapid detection of melamine in the field environment.