Plasmonic Nanosensors Research Articles

A stable and specific hydrogel-based plasmonic nanosensor for histamine detection

Plasmonic nanosensors have garnered increasing attention due to their naked-eye visibility and facile preparation. However, the inadequate stability and specificity significantly challenged their widespread application. Here, we hypothesized that capping with double-charged acids and loading in the hydrogel should bring gold nanoparticles (AuNPs) more stability and specificity for sensing small molecules. In the plasmonic nanosensor, aspartic acid-capped AuNPs (Asp-AuNPs) served as both the sensing material and colorant. Compared with conventional AuNPs, Asp-AuNPs exhibited a lower Zeta potential and enhanced selectivity for histamine. Moreover, Asp-AuNPs rapidly responded to histamine in less than 2 min, even after seven weeks of storage. The isothermal titration calorimetry analysis further supported the affinity of Asp-AuNPs for histamine. Using the alginate hydrogels as a matrix for Asp-AuNPs, the hydrogel-based plasmonic nanosensor could detect histamine on the surface of and in the atmosphere around expired fish. In summary, we have developed a novel, durable, and stable hydrogel-based plasmonic nanosensor for contact and contactless freshness detection.

A miniaturized microfluidic nanoplasmonic sensor with cavity reflection enhancement for ultrasensitive molecular interaction analysis

Molecular binding kinetics quantification is pivotal in the design of antibodies, small-molecule drugs, and early diagnosis of complex disease. This study presents a portable microfluidic system, featuring a nanoplasmonic sensor with cavity reflection enhancement (NSCRE), designed for the ultrasensitive detection and analysis of molecular interactions. This device comprises liquid flow paths, generic fiber spectrometers, a versatile NSCRE sensor chip, and a novel data analysis system. Furthermore, a neural network data processing system is developed based on a deep learning model to decrease significant data fluctuations caused by air segments. This “all-in-one” platform, integrating multifunctional, easy-to-use, and renewable NSCRE biosensors, boasts detection capabilities for both slow and rapid kinetics. It can automatically monitor interactions between molecules across a broad range of molecular weights (0.259–150 kDa), allowing for real-time, ultra-sensitive, and highly selective analysis. In addition, the platform with CRE effect facilitates a 7.2-fold increase in reflection intensity signals compared to that of a sensor without CRE. The immunoglobulin G detection with a limit of detection of 73 pM based on this device, showing a 50-fold increase in sensitivity compared to previously reported values. The miniaturized automatic detection system paves a new path for the use of molecular interaction analysis in life science research, drug discovery, early diagnosis, and other fields.

Pollen-based natural nanostructures to realize nanoplasmonic biochips for single-molecule detection

In this work, a paradigm change in the development of the plasmonic-based bio/chemical sensing approaches is presented. The proposed idea is to use natural nanostructures instead of those fabricated by electron-beam lithography (EBL) tools. This sensing approach produces several advantages, such as high performances without an optimization step and a simple, low-cost, and eco-friendly production process with respect to other methods, which are still time-consuming with low scalability. In particular, pollen's nanostructures covered by gold nanofilms are used to realize gold nanogratings (GNG), similar to those made via EBL, to excite hybrid plasmonic phenomena. Bulk and binding sensitivities are evaluated and compared to nanoplasmonic sensors, particularly those achieved via an EBL-based chip. As proof of principle, an estrogen receptor (ERα) is immobilized on the plasmonic nanostructured surfaces of both EBL-based and pollen-based chips and interrogated by the same custom 3D-printed holder through a transmission-based experimental setup, exploiting polymer optical fibers (POFs). The experimental results demonstrate that the proposed pollen-based nanoplasmonic biosensor shows performance very similar to an EBL-based nanoplasmonic biosensor, indicating the equivalence between the two nanoplasmonic biosensors. The biosensor exhibited a detection limit better than 1 aM for the estradiol, demonstrating the capabilities of the proposed sensing approach towards single-molecule detection.

Plasmonic nanosensors for environmental pollutants sensing: recent advances and perspectives

Plasmonic nanosensors for environmental pollutants sensing: recent advances and perspectives

Self-Assembled Plasmonic Structural Color Colorimetric Sensor for Smartphone-Based Point-Of-Care Ammonia Detection in Water.

Monitoring chemical levels is crucial for safeguarding both the environment and public health. Elevated levels of ammonia, for instance, can harm both humans and aquatic ecosystems, often indicating contamination from agriculture, industry, or sewage. Developing portable, high-resolution, and affordable methods for in situ monitoring of ammonia is thus imperative. Plasmonic sensors offer a promising solution, detecting ammonia by correlating changes in their optical response to the target analyte's concentration. While they are highly sensitive and can be fabricated in a variety of portable and user-friendly formats, some still require reagents or expensive optical equipment, which hinder their widespread adoption. Here, we present a self-assembled nanoplasmonic colorimetric sensor capable of directly detecting ammonia concentrations in aqueous matrices. The proposed sensor exploits the plasmonic resonance of the nanostructures to transduce changes in the chemical environment into alterations in color, offering a label-free method for real-time analysis. The sensor is fabricated using a self-assembling technique compatible with low-cost mass production based on aluminum and aluminum oxide, ensuring affordability and avoiding the use of other toxic chemicals. We developed a model to predict ammonia concentrations based on visible color change of the sensor, achieving a detection limit of 8.5 ppm. Furthermore, to address the need for on-site detection, we integrated smartphone technology for real-time color change analysis, eliminating the need for expensive, bulky optical instruments. Indeed, our approach offers a cost-effective, portable, and user-friendly solution for ammonia detection in water without the need for chemical reagents or spectrometers, making it ideal for field applications. Interestingly, this platform extends its applicability beyond ammonia detection, enabling the monitoring of various chemicals using a smartphone, without the need for any additional costly equipment.

Simulation study of a highly sensitive I-shaped Plasmonic nanosensor for sensing of biomolecules

This paper presents the design and simulation of an I-shaped metal insulator metal waveguide-based nanosensor for biosensing applications. The device’s sensing property is investigated using the three-dimensional finite element method. In the proposed design a I-shaped cavity is coupled to the main waveguide that serves as a resonator to generate the resonance peaks. The refractive index of the material to be sensed is filled inside the I-shaped cavity. This sensor operates in the near and mid-infrared wavelength ranges. The device can identify a variety of biomolecules, including cancer cells and bacterial samples. The simulation results reveal that device shows different resonance dips for different refractive indexes of cancer cells. The device can obtain sensitivity of 1550 nm RIU−1 and 1250 nm RIU−1 among refractive index of normal and cancerous cell for basal and hella cancer cells, respectively. Instead of all these biomolecules, the nanosensor shows different resonance dips in the transmittance spectrum for DNA, RNA, and ribonucleoprotein. Furthermore, the sensor has demonstrated potential applicability as an HB concentration detector and for sensing other blood components. Moreover, we improved the structure characteristics by varying the length and centre area of the cavity, demonstrating that modifying the device parameters can boost sensitivity. After making structural adjustments to the device, the maximum sensitivity of 3000 nm RIU−1 is achieved for some bacterial samples.

Formation of silver nanocrystals in Ag-Si composite films obtained by ion beam sputtering

Nanostructured composite films based on Ag-Si containing silver nanoparticles are used as a material for SERS (Surfaceenhanced Raman spectroscopy) substrates, plasmonic back reflector, nanoplasmonic sensors, nonlinear optics devices, memristor structures, etc. Due to the widespread use of nanocomposite films based on Ag-Si, there is a need to develop simple and affordable methods for their production compatible with semiconductor technology. Therefore, this work is devoted to the production of an Ag80Si20 nanocomposite film with a high silver content (80 at.%) by ion-beam sputtering with simultaneous control of the morphology, structure, phase composition and electrical properties of the manufactured sample. As a result of complex studies using X-ray diffraction, ultra-soft X-ray emission spectroscopy, SEM and AFMmicroscopy, it was found that the film is a nanocomposite material based on silver nanoparticles with an average size of ~15÷30 nm. At the same time, some silver nanoparticles are in direct contact, while some Ag nanoparticles are isolated from each other by a shell of silicon dioxide SiO2 and amorphous silicon a-Si. Such a nanogranulated structure of the Ag80Si20 film causes the presence in the test sample of the effect of switching from a high-resistance state (880 Ohm) to a lowresistance state (~1 Ohm) under the action of a voltage of ~ 0.2 V. As a result of the formation of conductive filaments (CF) of Ag atoms in the dielectric layer between the silver granules

Nanoplasmonic sensor optimization via digital imaging analysis and antibody evolution

Localized surface plasmon resonance (LSPR) biosensors have emerged as powerful analytical tools for detecting biomolecules like proteins, DNA, and RNA across biomedical research and diagnostics, owing to their exquisite sensitivity. While optimizing nanostructures, surface functionalization, and optics have enhanced sensor performance, LSPR imaging facilitates multi-parametric quantitative analysis by acquiring supplementary spatial, chromatic, and luminance data, improving detection precision and sensitivity. Here, we introduce an innovative integrated multi-molecular dynamics (MD) simulation approach to optimize surface functionalization, circumventing limitations of singular MD methods that may ignore system complexities. Exemplifying this strategy through affinity maturation of a SARS-CoV-2 spike protein-targeting human neutralizing antibody (hNAb), we employed a comprehensive MD simulation suite to engineer an hNAb variant (MT2) exhibiting significantly augmented binding affinity (KD = 9.2 nM) compared to wild-type (20.6 nM). Consequently, MT2 enabled more sensitive SARS-CoV-2 pseudovirion detection, limits of detection (LOD) is 2524 vp/mL (wild-type LOD = 4039 vp/mL). Furthermore, our multi-parametric hue-based analysis, leveraging chromatic variations in microscopic images, optimized the LSPR optical system, demonstrating heightened sensitivity in detecting pseudovirions (765 vp/mL) and spike protein (64.25 ng/mL).

A novel biomimetic nanoplasmonic sensor for rapid and accurate evaluation of checkpoint inhibitor immunotherapy

Immune checkpoint inhibitors (ICIs) emerged as promising immunotherapies for cancer treatment, harnessing the patient’s immune system to fight and eliminate tumor cells. However, despite their potential and proven efficacies, checkpoint inhibitors still face important challenges such as the tumor heterogeneity and resistance mechanisms, and the complex in vitro testing, which limits their widespread applicability and implementation to treat cancer. To address these challenges, we propose a novel analytical technique utilizing biomimetic label-free nanoplasmonic biosensors for rapid and reliable screening and evaluation of checkpoint inhibitors. We have designed and fabricated a low-density nanostructured plasmonic sensor based on gold nanodisks that enables the direct formation of a functional supported lipid bilayer, which acts as an artificial cell membrane for tumor ligand immobilization. With this biomimetic scaffold, our biosensing approach provides real-time, highly sensitive analysis of immune checkpoint pathways and direct assessment of the blocking effects of monoclonal antibodies in less than 20 min/test. We demonstrate the accuracy of our biomimetic sensor for the study of the programmed cell death protein 1 (PD1) checkpoint pathway, achieving a limit of detection of 6.7 ng/mL for direct PD1/PD-L1 interaction monitoring. Besides, we have performed dose–response inhibition curves for an anti-PD1 monoclonal antibody, obtaining a half maximal inhibitory concentration (IC50) of 0.43 nM, within the same range than those obtained with conventional techniques. Our biomimetic sensor platform combines the potential of plasmonic technologies for rapid label-free analysis with the reliability of cell-based assay in terms of ligand mobility. The biosensor is integrated in a compact user-friendly device for the straightforward implementation in biomedical and pharmaceutical laboratories.Graphical

Advances in Nanoplasmonic Biosensors: Optimizing Performance for Exosome Detection Applications.

The development of sensitive and specific exosome detection tools is essential because they are believed to provide specific information that is important for early detection, screening, diagnosis, and monitoring of cancer. Among the many detection tools, surface-plasmon resonance (SPR) biosensors are analytical devices that offer advantages in sensitivity and detection speed, thereby making the sample-analysis process faster and more accurate. In addition, the penetration depth of the SPR biosensor, which is <300 nm, is comparable to the size of the exosome, making the SPR biosensor ideal for use in exosome research. On the other hand, another type of nanoplasmonic sensor, namely a localized surface-plasmon resonance (LSPR) biosensor, has a shorter penetration depth of around 6 nm. Structural optimization through the addition of supporting layers and gap control between particles is needed to strengthen the surface-plasmon field. This paper summarizes the progress of the development of SPR and LSPR biosensors for detecting exosomes. Techniques in signal amplification from two sensors will be discussed. There are three main parts to this paper. The first two parts will focus on reviewing the working principles of each sensor and introducing several methods that can be used to isolate exosomes. This article will close by explaining the various sensor systems that have been developed and the optimizations carried out to obtain sensors with better performance. To illustrate the performance improvements in each sensor system discussed, the parameters highlighted include the detection limit, dynamic range, and sensitivity.

Liquid-metal-based microfluidic nanoplasmonic platform for point-of-care naked-eye antibody detection

Despite high sensitivity of nanoparticle-on-mirror cavities, a crucial branch of plasmonic nanomaterials, complex preparation and readout processes limit their extensive application in biosensing. Alternatively, liquid metals (LMs) combining fluidity and excellent plasmonic characteristics have become potential candidates for constructing plasmonic nanostructures. Herein, we propose a microfluidic-integration strategy to construct LM-based immunoassay platform, enabling LM-based nanoplasmonic sensors to be used for point-of-care (POC) clinical biomarker detection. Flowable LM is introduced onto protein-coated Au nanoparticle monolayer to form a “mirror-on-nanoparticle” nanostructure, simplifying the fabrication process in the conventional nanoparticle-on-mirror cavities. When antibodies were captured by antigens coated on the Au nanoparticle monolayer, devices respond both thickness and refractive index change of biomolecular layers, outputting naked-eye readable signals with high sensitivity (limit of detection: ∼ 604 fM) and a broad dynamic range (6 orders). This new assay, which generates quantitative results in 30 min, allows for high-throughput, smartphone-based detection of SARS-CoV-2 antibodies against multiple variants in clinical serum or blood samples. These results establish an advanced avenue for POC testing with LM materials, and demonstrate its potential to facilitate diagnostics, surveillance and prevalence studies for various infectious diseases.

Plasmonic nanosensor and pressure-induced transparency based on coupled resonator in a nanoscale system.

Plasmonic nanosensors and the dynamic control of light fields are of the utmost significance in the field of micro- and nano-optics. Here, our study successfully demonstrates a plasmonic nanosensor in a compact coupled resonator system and obtains the pressure-induced transparency phenomenon for the first time to our knowledge. The proposed structure consists of a groove and slot cavity coupled in the metal-insulator-metal waveguide, whose mechanical and optical characteristics are investigated in detail using the finite element method. Simulation results show that we construct a quantitative relationship among the resonator deformation quantity, the applied pressure variation, and the resonant wavelength offset by combining the mechanical and optical properties of the proposed system. The physical features contribute to highly efficient plasmonic nanosensors for refractive index and optical pressure sensing with sensitivity of 1800 nm/RIU and 7.4 nm/MPa, respectively. Furthermore, the light waves are coupled to each other in the resonators, which are detuned due to the presence of pressure, resulting in the pressure-induced transparency phenomenon. It is noteworthy to emphasize that, unlike previously published works, our numerical results take structural deformation-induced changes in optical properties into account, making them trustworthy and practical. The proposed structure introduces a novel, to the best of our knowledge, approach for the dynamic control of light fields and has special properties that can be utilized for the realization of various integrated components.

Ultrathin Parylene C-based sensitivity-gain nanoplasmonic sensor integrated on VCSEL for Aβ42 detection

As Alzheimer's disease prevalence continues to rise, there is an increasing demand for efficient on-chip biosensors capable of early biomarker detection. This study presents a novel biosensor chip leveraging vertical cavity surface emitting laser (VCSEL) technology, with Parylene C serving as the antibody coupling layer and utilizing a streamlined one-step antibody modification method. Integration of Parylene C enhances chip sensitivity from 34.28 μW/RIU to 40.32 μW/RIU. Moreover, post-testing removal of Parylene C enables chip reusability without significant alteration of results. The sensor demonstrates effective detection of Aβ42, an Alzheimer's biomarker, exhibiting a linear range of 1–200 ng/mL and a detection limit of 0.26 ng/mL. These findings underscore the reusability and reliability of the ultrathin Parylene C-based VCSEL biosensor chip, highlighting its potential for point-of-care Alzheimer's disease diagnosis.

High Dynamic Range Probing of Single-Molecule Mechanical Force Transitions at Cell-Matrix Adhesion Bonds by a Plasmonic Tension Nanosensor.

Mechanical signals in animal tissues are complex and rapidly changed, and how the force transduction emerges from the single-cell adhesion bonds remains unclear. DNA-based molecular tension sensors (MTS), albeit successful in cellular force probing, were restricted by their detection range and temporal resolution. Here, we introduced a plasmonic tension nanosensor (PTNS) to make straight progress toward these shortcomings. Contrary to the fluorescence-based MTS that only has specific force response thresholds, PTNS enabled the continuous and reversible force measurement from 1.1 to 48 pN with millisecond temporal resolution. We used the PTNS to visualize the high dynamic range single-molecule force transitions at cell-matrix adhesions during adhesion formation and migration. Time-resolved force traces revealed that the lifetime and duration of stepwise force transitions of molecular clutches are strongly modulated by the traction force through filamentous actin. The force probing technique is sensitive, fast, and robust and constitutes a potential tool for single-molecule and single-cell biophysics.

Neural network enabled nanoplasmonic hydrogen sensors with 100 ppm limit of detection in humid air

Environmental humidity variations are ubiquitous and high humidity characterizes fuel cell and electrolyzer operation conditions. Since hydrogen-air mixtures are highly flammable, humidity tolerant H2 sensors are important from safety and process monitoring perspectives. Here, we report an optical nanoplasmonic hydrogen sensor operated at elevated temperature that combined with Deep Dense Neural Network or Transformer data treatment involving the entire spectral response of the sensor enables a 100 ppm H2 limit of detection in synthetic air at 80% relative humidity. This significantly exceeds the <1000 ppm US Department of Energy performance target. Furthermore, the sensors pass the ISO 26142:2010 stability requirement in 80% relative humidity in air down to 0.06% H2 and show no signs of performance loss after 140 h continuous operation. Our results thus demonstrate the potential of plasmonic hydrogen sensors for use in high humidity and how neural-network-based data treatment can significantly boost their performance.

Sulfhydryl-mediated etching suppression of gold nanostars for rapid and sensitive detection of bacterial pathogens

Human infectious diseases caused by bacterial pathogens, such as meningitis and pyaemia, threaten the public health worldwide due to their acute onset and high mortality. Sensitive and rapid detection of bacterial pathogens is urgent for the treatment of infectious diseases clinically. However, current techniques are generally time-consuming and require large-scale equipment. Plasmonic nanosensors built on metallic nanomaterials have emerged as excellent tools for biomedical diagnostics. Herein, we report an etching suppression strategy for the sensitive and rapid detection of bacterial pathogens through gold nanostars. Sulfhydryl-containing ligands suppress the iodide-mediated surface etching of gold nanostars, depending on the type, concentration, and size of sulfhydryl-containing ligands. Using mercaptophenylboronic acid (MBA) and Pseudomonas aeruginosa (P. aeruginosa)-specific aptamer as multifunctional ligands, we specifically identify bacterial pathogens through sulfhydryl-mediated etching suppression with a linear detection range from 10 to 106 CFU/mL and a limit of detection of 2 CFU/mL. This etching suppression-based strategy enables the detection of Neisseria meningitidis in the cerebrospinal fluid and P. aeruginosa in the serum within 15 min, showing great potential as a point-of-care platform for clinical diagnosis.

Metabolism-Triggered Plasmonic Nanosensor for Bacterial Detection and Antimicrobial Susceptibility Testing of Clinical Isolates.

Antimicrobial resistance (AMR) is predicted to become the leading cause of death worldwide in the coming decades. Rapid and on-site antibiotic susceptibility testing (AST) is crucial for guiding appropriate antibiotic choices to combat AMR. With this in mind, we have designed a simple and efficient plasmonic nanosensor consisting of Cu2+ and cysteine-modified AuNP (Au/Cys) that utilizes the metabolic activity of bacteria toward Cu2+ for bacterial detection and AST. When Cu2+ is present, it induces the aggregation of Au/Cys. However, in the presence of bacteria, Cu2+ is metabolized to varying extents, resulting in distinct levels of aggregation. Moreover, the metabolic activity of bacteria can be influenced by their antibiotic susceptibility, allowing us to differentiate between susceptible and resistant strains through direct color changes from the Cu2+-Au/Cys platform over approximately 3 h. These color changes can be easily detected using naked-eye observation, smartphone analysis, or absorption readout. We have validated the platform using four clinical isolates and six types of antibiotics, demonstrating a clinical sensitivity and specificity of 95.8%. Given its simplicity, low cost, high speed, and high accuracy, the plasmonic nanosensor holds great potential for point-of-care detection of antibiotic susceptibility across various settings.

Flexible nanoplasmonic sensor for multiplexed and rapid quantitative food safety analysis with a thousand-times sensitivity improvement

The accumulation of trace amounts of certain small molecules in food poses considerable human health challenges, including the potential for carcinogenesis and mutagenesis. Here, an ultrasensitive gold–platinum nanoflower-coupled metasurface plasmon resonance (MetaSPR) (APNMSPR) biosensor, based on a competitive immunoassay, was developed for the multiplexed and rapid quantitative analysis of trace small molecules in eggs, offering timely monitoring of food safety. This one-step biosensor can be integrated into either a newly designed detachable high-throughput MetaSPR chip-strip plate device or a standard 96-well plate for multiplexed small-molecule detection within a single egg. The limits of detection were 0.81, 1.12, and 1.74 ppt for florfenicol, fipronil, and enrofloxacin, respectively, demonstrating up to 1000-fold increased sensitivity and a 15-fold reduction in analysis time compared with those of traditional methods. The results obtained using the APNMSPR biosensor showed a strong correlation with those obtained using liquid chromatography–tandem mass spectrometry. The APNMSPR biosensor holds immense promise for the multiplexed, highly sensitive, and rapid quantitative analysis of small molecules for applications in food safety control, early diagnosis, and environmental monitoring.

(Invited) Plasma-Synthesized Coupled Nanoplasmonic Gold for DNA Sersing

The facilitated electrochemical properties of plasma play a critical role in enhancing the synthesis and design of functional nanomaterials for the development of novel sensors. The targeted challenge is to customize and tailor functionality at multiple scales to improve detection device performance. In the realm of optoelectronics, plasmonic sensing is considered an efficient tool for investigating molecular properties, often accompanied by Raman, FTIR or Fluorescent spectroscopy. Specifically, Raman scattering, also known as SERS (surface-enhanced Raman scattering), is commonly used to probe analytes at a reduced scale using plasmonic enhancers. This technique is especially useful for rapidly and accurately investigating biologically relevant samples, such as DNA and RNA. DNA/RNA-related investigations are crucial in modern nanomedicine due to the progress made in bionanotechnology, DNA vaccines, and functional gene engineering. DNA, in particular, is highly valued by microbiologists because it contains information about the nature of bio-species. Currently, PCR-related methods dominate the field for molecular-sensitive DNA-level studies, but it is challenging to investigate using optical techniques like SERS. Despite its promise, SERS still requires technological and analytical improvements. A sophisticated plasmonic nanomaterial provides considerably improved photon scattering due to the strongly localized field confinement effect, resulting in better performance. In this report, a nanoplasmonic sensor was designed using a plasma-driven electrochemical reduction mechanism, achieved through an atmospheric pressure He-plasma jet setup operating at kHz frequency. The reactive oxidative species donated electrons via liquid-gas electrochemistry towards the Ar-delivered Au(3+)-containing microdroplets, resulting in microscaled aggregates composed of AuNPs obtained from the nebulized ionic gold liquid precursor. Due to the strong coupling between nanoparticles, a high analytical enhancement factor of about 107 was achieved, and the substrate enabled obtaining Raman fingerprints of bacterial DNA fragments (M. luteus and S. aureus, E. coli, J. lividum) at nanovolume sample quantities. Additionally, the main DNA molecular vibrational signatures associated with nucleobase motions were extracted from the collected spectra and used to reliably classify bacterial strains using statistical principal component analysis.[1] References[1] Shvalya, V., Vasudevan, A., Modic, M., Abutoama, M., Skubic, C., Nadižar, N., ... & Cvelbar, U. (2022). Bacterial DNA Recognition by SERS Active Plasma-Coupled Nanogold. Nano Letters.

A comprehensive study on the Rod-based plasmonic structures sensing using the modified discrete dipole approximation method

Using the previously introduced modified discrete dipole approximation (DDA) method by applying the full details of the nanoparticle and its surrounding environment, the detection sensitivity of molecules by plasmonic Rod-based nanosensors, including U-shaped and Rod-shaped structures, was investigated. In the calculations, the two factors of the magnitude of the wavelength shift and the ability to distinguish molecules with similar properties were of significant interest. The results indicated that the sensitivity of Rod-based nanostructures is significantly higher than that of spherical nanoparticles. Among the plasmonic Rod-based nanosensors, the silver U-shaped structure performs better than others. The wavelength shift of the absorption spectrum of different nanosensors for a given molecule was very different, making it possible to detect very similar molecules from each other by testing different sensors.