Signal Amplification Technique Research Articles

Total losses and dispersion effects management and upgrading fiber reach in ultra-high optical transmission system based on hybrid amplification system

Abstract This work demonstrated the total losses and dispersion effects management and upgrading the fiber reach in ultra-high optical transmission system based on hybrid amplification system. Based on the requirements of the system, a number of trade-offs must be made between the numerous interconnected performance characteristics of each component in the design of a high quality transmission link. The transmission distance is the greatest distance that an optical signal has to travel. It affects the choice of optical component, fiber type, and signal amplification techniques. Fiber amplifiers or signal regeneration may be required to compensate for signal loss over greater distances. Reviewing these crucial aspects helps when selecting the best optical components and system layout. This ensures the optical link performs as expected. Hybrid amplification system unit (EDFA/Raman/EDFA), (EDFA/Raman), (BFA/PDFA) and (Raman/EDFA) is employed in the transmission system to strength the signal and upgrade the system performance operation efficiency. Space division multiplexing scheme is also employed with the propagation scheme in order to upgrade and control of the total losses and dispersion effects. The optimum total losses/dispersion/repeater spacing are studied with the variations of the total number of links per fiber core channel.

Functional Interface for Glycoprotein Sensing: Focusing on Biosensors.

Glycosylated proteins or glycoproteins make up a large family of glycoconjugates, and they participate in a variety of fundamental biological events. Glycoproteins have become important biomarkers in the diagnosis and treatment of a number of tumors. Biosensors are quite suitable for glycoprotein detection. The design and fabrication of a functional sensing interface play a crucial role in the biosensor construction to target glycoproteins. The functional interface, particularly receptors, typically determines the key characteristics of a biosensor, such as selectivity and sensitivity. Antibody, peptide, aptamer, boronic acid derivative, lectin, and molecularly imprinted polymer are all capable receptors for glycoprotein recognition, and each of these will be discussed. Most glycoproteins exist in low abundance, thus rendering signal amplification techniques indispensable. Nucleic acid-mediated and nanomaterial-mediated signal amplification for the detection of glycoproteins will be focused on herein. This review aims to highlight these different functional interfaces for glycoprotein sensing.

Augmented Fluorescence Signaling on a Single BaTiO3 Microbead Optical Booster toward High-Sensitive Biosensing.

In this work, we report a new generation of single microbead bioassay that employs a single BaTiO3 microbead as an optical booster for target biomarker enrichment and optical enhancement toward protein and nucleic acid analysis. The single BaTiO3 microbead can not only concentrate the target molecules by nearly 104-fold but also act as an optical booster to prominently enhance the target-induced fluorescence signal by the whispering gallery mode for improving the excitation efficiency and the microlens effect for promoting the signal collecting efficiency, respectively. Compared with using a conventional single microbead, this optical booster exhibits nearly 2 orders of magnitude higher sensitivity without the assistance of any signal amplification techniques or costly instruments. Moreover, this single microbead optical booster is capable of detecting different kinds of protein and nucleic acid biomarkers in a simple mix-and-read manner, holding great potential for early clinical diagnosis.

Metal Ion‐Mediated Optical Biosensors with Signal Amplification: Recent Advances

AbstractSignal amplification is critical for the detection of meaningful trace targets in the field of biomedicine, food analysis, and environmental protection. A growing number of signal amplification techniques for biosensors involving metal ions have been reported in recent years, due to the merits of simplicity, low cost, and high efficiency. This review summarizes the recent advancement and outlines the signaling methods (i. e. metal‐responsive probes, metal‐catalyzed reactions, regulating catalysis, and atom spectrometry) that metal ions play in biosensing as well as their applications. Besides, the potential and challenges to be addressed in the field are discussed.

Coherent phonon signal amplification technique based on a numerical differentiation method

Coherent optical phonon (COP) and coherent acoustic phonon (CAP) play vital roles in probing ultrafast dynamics across various materials and systems. Their applications range from metamaterial diagnosis to manipulating ferroelectric polarization and self-trapping of carriers in perovskites. However, the inherently small signals associated with COP and CAP pose challenges in extracting valuable information. In this paper, we address this challenge by presenting a numerical differential method for signal amplification and deduction of phonon dephasing time. In addition, application of this method has been demonstrated in a superlattice system, establishing the validity and effectiveness of this technique.

A facile nickel nanocluster-based fluorescent ‘‘turn-off” sensor to detect tetracycline antibiotics

Developing an effective method for monitoring of tetracycline (TC) concentrations is extremely crucial due to its adverse effects on both ecosystems and human health. In this study, we developed a novel glutathione-protected nickel nanoclusters (GSHNiNCs) fluorescent (FL) sensing platform to detect TC. The GSHNi NCs were synthesized by a facile one-pot route with GSH as a stabilizer and ascorbic acid (AA) as reducing agent. The experimental results confirmed that the FL of GSHNiNCs was quenched in the presence of TC based on both of the inner-filter effect (IFE) and photoinduced electron transfer (PET) mechanisms to achieve high sensitivity. Under the optimal conditions, excellent linear relationships existed between the FL intensities of GSHNiNCs and the logarithmic TC concentrations in the range of 0.5–120.0 and 120.0–300.0 μM. Even in the absence of surface modification or any complex signal amplification techniques, the proposed FL sensing platform for TC detection showed a low limit of detection of 58 nM (3σ/k). Thus, this approach provides considerable simplicity, low-cost, timesaving and flexibility for the construction of a TC sensor. Most remarkably, we could selectively analyze TC in milk samples without the need for tedious or time-consuming pretreatment processes. This work expands the FL analysis platform for TC detection, and facilitates the design and development of NiNC-based FL sensors for the monitoring of antibiotics.

Exploring T7 RNA polymerase-assisted CRISPR/Cas13a amplification for the detection of BNP via electrochemiluminescence sensing platform

Brain natriuretic peptide (BNP) is considered to be an important biomarker of heart failure (HF) attracting attention. However, its low concentration and short half-life in blood lead to a low-sensitivity detection of BNP, which is a challenge that has to be overcome. In this work, we propose a highly specific, highly sensitive T7 RNA polymerase-assisted clustered regularly interspaced short palindromic repeats (CRISPR)/Cas13a system to detect BNP via an electrochemiluminescence (ECL) sensing platform and incorporate exonuclease III (Exo III)-hairpin and dumbbell-shaped hybridization chain reaction (HCR) technologies. In this detection scheme, the ECL sensing platform possesses low background signal and high sensitivity. Firstly, the T7 promoter-initiated T7 RNA polymerase acts as a signal amplification technique to generate large amounts of RNAs that can activate CRISPR/Cas13a activity. Secondly, CRISPR/Cas13a is able to trans-cleave the surrounding trigger strand to produce DNA1. Thirdly, DNA1 is involved in the co-amplification reaction of Exo III and hairpin DNA, which subsequently triggers a dumbbell-shaped HCR technology. Eventually, a large number of Ru (II) molecules are inserted into the interstitial space of the dumbbell-shaped HCR to generate a strong ECL signal. The CRISPR/Cas13a possesses outstanding specificity for a single base and increased sensitivity. The tightly conformed dumbbell-shaped HCR provides higher sensitivity than the traditional linear HCR amplification technique. Ultimately, the clever combination of several amplification reactions enables the limit of detection (LOD) as low as 3.2 fg/mL. It showed promise for clinical sample testing, with recovery rates ranging from 98.4% to 103% in 5% human serum samples. This detection method offered a valuable tool for early HF detection, emphasizing the synergy of amplification strategies and specificity conferred by CRISPR/Cas13a technology.

Recent advances in design strategies of aptamer‐based liquid biopsy

AbstractLiquid biopsy represents a groundbreaking technology enabling the detection, analysis, and monitoring of circulating targets in body fluids, such as blood, to acquire crucial molecular insights into tumorigenesis and progression mechanisms. Offering non‐invasiveness and real‐time capabilities, liquid biopsy facilitates the tracking of tumor evolutionary dynamics and exploration of tumor heterogeneity, thereby holding immense value for tumor diagnosis, personalized treatment, and prognostication. Therefore, an effective analysis of circulating targets in body fluids is essential. However, the complexity of biological systems poses notable challenges to achieving high sensitivity and accuracy in liquid biopsy. Aptamers possess inherent advantages of high specificity and affinity, with the added benefit of modifiability and design flexibility to enhance their performance under different practical conditions, rendering them ideal recognition elements for liquid biopsy. This review provides a comprehensive summary of design strategies for aptamer applications in liquid biopsy, including advanced aptamer screening strategies, aptamer‐based recognition designs, and signal amplification techniques. Ultimately, we present an outlook into the future prospects and directions of aptamer applications in the liquid biopsy.

A novel photoelectrochemical phage sensor based on WO3/Bi2S3 for Escherichia coli detection

To achieve rapid detection of Escherichia coli, a photoelectrochemical phage sensor was constructed. WO3 and Bi2S3 composite nanomaterials were used as photosensitive materials, and Au nanoparticles were linked to T4 phage and modified on the electrode surface to achieve high sensitivity detection. Bi2S3 was modified on the surface of the WO3 electrode by successive ionic layer adsorption and reaction to form the heterojunction to reduce the complexation of electron-hole pairs. The sensor constructed with T4 phage as the recognition element has excellent recognition specificity and a lower detection limit, which compensates for the inability of other recognition elements to distinguish between live and dead bacteria. Various signal amplification techniques are flexibly combined to improve the photocurrent response before and after analyte identification, thereby improving the sensitivity of the sensor.

Exosomes as Powerful Biomarkers in Cancer: Recent Advances in Isolation and Detection Techniques.

Exosomes, small extracellular vesicles derived from cells, are known to carry important bioactive molecules such as proteins, nucleic acids, and lipids. These bioactive components play crucial roles in cell signaling, immune response, and tumor metastasis, making exosomes potential diagnostic biomarkers for various diseases. However, current methods for detecting tumor exosomes face scientific challenges including low sensitivity, poor specificity, complicated procedures, and high costs. It is essential to surmount these obstacles to enhance the precision and dependability of diagnostics that rely on exosomes. Merging DNA signal amplification techniques with the signal boosting capabilities of nanomaterials presents an encouraging strategy to overcome these constraints and improve exosome detection. This article highlights the use of DNA signal amplification technology and nanomaterials' signal enhancement effect to improve the detection of exosomes. This review seeks to offer valuable perspectives for the enhancement of amplification methods applied in practical cancer diagnosis and prognosis by providing an overview of how these novel technologies are utilized in exosome-based diagnostic procedures.

An eco-friendly and ultrasensitive micro-orifice resistance assay for the detection of Listeria monocytogenes based on calcium carbonate signal probes harvested from discarded eggshells

The development of eco-friendly analytical methods for the detection of foodborne pathogens is of great importance for protecting human health and alleviating environmental pressure. Here, we demonstrate that a material (CaCO3 microparticles) prepared from discarded eggshells can be used as signal probes for micro-orifice resistance assay (MORA) and can be combined with ligation-mediated branching hybridization chain reaction (LB-HCR)-based signal-amplification technique (e-LMORA) for high sensitivity detection of Listeria monocytogenes. This strategy used LB-HCR-induced aggregation of streptavidin-modified CaCO3 microparticles, which were recognized by the particle counter for quantitative analysis of the target DNA. Compared with traditional MORA using polystyrene microspheres as signal probes, CaCO3 microparticles prepared from waste eggshells are more environmentally friendly. The combination of DNA-recognition probe, signal probes, and enzyme-free signal-amplification strategy not only reduces the cost synergistically, but also enables the biosensor to attain high sensitivity (limit of detection = 21 CFU/mL) due to its efficient signal amplification.

Developing Porous Microneedles Patch for the Detection of Wound Infections

AbstractWound infections caused by invasive pathogens become an increasing global challenge health. Porous microneedles (MNs) present distinctive advantages for non‐invasive and in situ detection of wound infections, enabling the extraction of interstitial fluid, skin sweat, saliva and other biological samples. Consequently, porous MNs find widespread acceptance in medical detection, drug delivery, and monitoring physiological indicators. Based on these advantages, the emerging clinical applications and classifications of MNs is first introduced, covering mechanical strength, methods for antibody probe modification onto porous MNs, and signal amplification techniques for biomarkers analysis. At the same time, the specific applications of immunology and electrochemistry on porous MNs, introducing methods to enhance the detection signal of target molecules, such as rolling circle amplification, gold/silver nanoparticles, fluorescence amplification origami microneedle and so on is try to summarized. The improvement of detection sensitivity is realized by integrating various signal amplification strategies and diverse detection methods. Meanwhile, it is briefly illustrated applications in wound detections. Finally, challenges and future prospects of using porous MNs for detection in practical applications is discussed.

Lysosomes Initiating and DNAzyme-Assisted Intracellular Signal Amplification Strategy for Quantification of Alpha-Fetoprotein in a Single Cell.

Cellular trace proteins are critical for maintaining normal cell functions, with their quantitative analysis in individual cells aiding our understanding of the role of cell proteins in biological processes. This study proposes a strategy for the quantitative analysis of alpha-fetoprotein in single cells, utilizing a lysosome microenvironment initiation and a DNAzyme-assisted intracellular signal amplification technique based on electrophoretic separation. A nanoprobe targeting lysosomes was prepared, facilitating the intracellular signal amplification of alpha-fetoprotein. Following intracellular signal amplification, the levels of alpha-fetoprotein (AFP) in 20 HepG2 hepatoma cells and 20 normal HL-7702 hepatocytes were individually evaluated using microchip electrophoresis with laser-induced fluorescence detection (MCE-LIF). Results demonstrated overexpression of alpha-fetoprotein in hepatocellular carcinoma cells. This strategy represents a novel technique for single-cell protein analysis and holds significant potential as a powerful tool for such analyses.

Near-infrared electrochemiluminescence of defect-rich molybdenum disulfide quantum dots for sensitive bioanalysis

Developing high-efficiency near-infrared (NIR) electrochemiluminescence (ECL) active transition metal dichalcogenides quantum dots (TMDs QDs) for spectroscopic multiplex analysis and biological imaging poses a significant challenge in versatile bioanalysis. In this work, we report a facile one-step hydrothermal method for the synthesis of defect-rich molybdenum disulfide quantum dots (MoS2 QDs). Because of the defect effect on the nanocrystalline surface, the MoS2 QDs exhibit enhanced fluorescence (quantum yield is 7.7%) in comparison with those from top-down physical approaches. Moreover, the defect-rich MoS2 QDs exhibit remarkable ECL performance using K2S2O8 as a coreactant, with a maximum emission at ∼810 nm. The ECL mechanisms of potential-dependent emission from MoS2 QDs were elucidated based on electrochemistry, photoluminescence, and spooling ECL spectroscopy. Leveraging the good biocompatibility and defect-induced ECL enhancement of MoS2 QDs, a sandwich ECL immunosensor was developed for carcinoembryonic antigen (CEA) detection. Without any signal amplification techniques, the proposed biosensor demonstrated a detection limit of 0.005 ng/mL CEA with a linear range from 0.005 ng/mL to 400 ng/mL, and a good selectivity and potential for real human serum analysis. The defect engineering of MoS2 QDs in this study provides guidance for regulating their optical properties and exploring new bioanalysis applications.

Hybridization chain reaction assisted terahertz metamaterial biosensor for highly sensitive detection of microRNAs

MicroRNA (miRNA) is closely related to the occurrence and development of cancer. Accurate determination of the miRNA concentration is of great significance for early cancer diagnosis. However, due to the short sequence and low concentration of miRNA, it is still a challenge to achieve low-concentration detection. In this work, we proposed a method for the highly sensitive detection of miRNA-21 using a terahertz (THz) metamaterial sensor combined with a Hybridization chain reaction (HCR). First, a capture hairpin probe was combined with gold nanoparticles (AuNPs), which were then modified to the surface of the sensor for specific binding of miRNA-21. Then the signal amplification technique of HCR is used to amplify the trace amount of miRNA, and the super-long dendritic DNA macromolecules are formed on the surface of the sensor. This changes the dielectric environment of the sensor surface, and the resonance frequency of the sensor is shifted. The method has good specificity and sensitivity, and the concentration of miRNA-21 in the range of 100 aM to 10 nM shows excellent linear relationship with frequency shift. Most importantly, it paves the way for low-cost, easy-to-operate and marker-free miRNA detection.

The Application of Hybridization Chain Reaction in the Detection of Foodborne Pathogens.

Today, with the globalization of the food trade progressing, food safety continues to warrant widespread attention. Foodborne diseases caused by contaminated food, including foodborne pathogens, seriously threaten public health and the economy. This has led to the development of more sensitive and accurate methods for detecting pathogenic bacteria. Many signal amplification techniques have been used to improve the sensitivity of foodborne pathogen detection. Among them, hybridization chain reaction (HCR), an isothermal nucleic acid hybridization signal amplification technique, has received increasing attention due to its enzyme-free and isothermal characteristics, and pathogenic bacteria detection methods using HCR for signal amplification have experienced rapid development in the last five years. In this review, we first describe the development of detection technologies for food contaminants represented by pathogens and introduce the fundamental principles, classifications, and characteristics of HCR. Furthermore, we highlight the application of various biosensors based on HCR nucleic acid amplification technology in detecting foodborne pathogens. Lastly, we summarize and offer insights into the prospects of HCR technology and its application in pathogen detection.

T4PPVB-COP composite-driven innovative electrochemiluminescence aptasensor for ultra-sensitive detection of chlorpyrifos.

Herein, an enhanced electrochemiluminescence (ECL) aptasensor driven by a complex (T4PPVB-COP@CdS QDs) with large specific surface area and high stability was constructed for highly sensitive detection of chlorpyrifos (CPF), using electrostatic interactions and signal amplification techniques. In the presence of CPF, the specific binding between the aptamer and CPF caused partial detachment of the aptamer from the sensor, thus restoring the ECL signal. Notably, gold nanoparticles functionalized with streptavidin (SA) as signal enhancers further amplified the ECL signal in specific interactions with aptamers, thereby improving the sensitivity of the assay. Based on this, the proposed ECL aptasensor demonstrated significant detection performance for CPF with a linear range of 1-107pg/mL and a LOD of 0.34pg/mL. Furthermore, the feasibility of the ECL aptasensor was validated by the detection and analysis of CPF in real samples, which also provided a broad reference value for bioanalysis.

Attomole Electrochemical Detection of MicroRNAs Based on Surface-Initiated Enzymatic Polymerization Coupled with Copper Enhancement

The sensitive and effective detection of microRNAs (miRNAs) is of great significance since miRNAs have been proven to have undeniable importance in participating in many biological processes. Herein, we present a novel, sensitive, label-free electrochemical miRNA detection method. Three signal amplification techniques are incorporated in this method, including the efficient conjugate of primer-modified polystyrene spheres (PS) with magnetic beads (MBs) triggered by target miRNA, template-free surface-initiated enzymatic polymerization (SIEP) on the primers, and the use of copper ions in square wave voltammetry (SWV) for detecting acidically depurinated primers. Cooperating with the electrochemical approach, this method was able to achieve a detection limit of 120 aM. With an attomole level of sensitivity and easiness of manipulation, this novel method is suitable for miRNA routine detection in both research and clinical aspects.

Duplex-specific nuclease assisted magnetic nanoprobe for cyclic amplified RNA detection

The recent spreading of viral diseases has led to the outbreak of pandemic and caused severe threats to public health worldwide. Though various approaches have been developed to detect viruses, there have only been a few reports on detecting viral RNA by cyclic signal amplification techniques. In search of an easy, cost-effective alternate method of gold-standard polymerase chain reaction (PCR), here, we have developed a duplex-specific nuclease (DSN)-based signal amplification method for RNA detection designing specific ssDNA-based nanoprobes. In the presence of target RNA under optimized conditions, DSN cleaves specifically the ssDNA in the DNA-RNA heteroduplex of the sensor to release the fluorophore from its quenched state while leaving the RNA strand free to react with another available nanoprobe for cyclic amplification. In this process, a single target RNA can interact with large numbers of nanoprobes, releasing amplified fluorophores from the core of the nanoprobes and increasing the fluorescence. The low detection limit of 11.5 fM has been achieved for a short-chain target RNA, indicating its potential application for the rapid RNA detection.

Retracted: Application of Isothermal Signal Amplification Technique in the Etiological Diagnosis of Gonorrhea and Drug Resistance Gene Detection.

[This retracts the article DOI: 10.1155/2022/5989889.].