Detection Of Biomolecules Research Articles

Application of ultrasensitive single molecule immunoassay technology in clinical biomarker detection

Single-molecule immunoassay technology represents an ultrasensitive immunoassay method that enables the resolution and detection of individual biomolecules at the nanoscale. This article highlights various representative techniques and clinical applications of single-molecule immunoassay technology, while also discussing the current challenges and future development directions. Through multiple optimizations at both the technical and commercial levels, single-molecule immunoassay technology exhibits unique advantages in real-time detection, disease diagnosis and treatment, and medical research. This technology is poised to contribute to the advancement of precision medicine by integrating individualized detection methods into clinical practice.

Implementation of quality by design approach for optimization of the green voltammetric analysis of a brain doping agent (Piracetam) using a novel molecular imprinted polymeric sensor

It is encouraging to note that in recent years there has been a growth of high-quality articles detailing molecular imprinted sensors for the detection of biomolecules, illicit narcotics, and explosives, paving the way for the technology’s usage in forensic and medical diagnostics.Thus in this work, a molecularly imprinted polymeric sensor was fabricated, for the first time, for the sensitive and selective determination of a brain doping agent; Piracetam, using a pencil-graphite electrode. This sensor was created by the simple anodic electro-polymerization of o-phenylenediamine (o-PD) with Piracetam as the template. Then the sensor was activated by removing the template using a suitable solvent mixture. Because of Piracetam’s lack of electro-activity, [Fe (CN)6]3−/4− has been used as an electrochemical probe that produces analytically relevant voltammetric signals by competing for the binding sites. Based on UV-spectrophotometric measurements, Job’s approach confirmed the expected stoichiometric ratio between Piracetamand the chosen monomer. X-ray photoelectron spectroscopy and cyclic voltammetry techniques were used for the characterization of the fabricated sensors. Different factors affecting the electro-polymerization conditions as; the effect of scan rate, number of cycles, pH of electro-polymerization, and the incubation time for rebinding were studied and optimized using fractional factorial design, in which the predicted model fits well to the experimental data as proved by ANOVA results. The developed voltammetric platform was applied for the in-line quantification of Piracetam in its pure solutions, pharmaceutical dosage form, and spiked human plasma with high accuracy and selectivity without the interference of the co-formulated drug; Citicoline sodium and excipients. The proposed molecular imprinted sensor was very sensitive with a linearity range (1.00 × 10−13 − 1.00 × 10−12 M), with LOD down to 4.38 × 10−15 M. This method was statistically compared with the reported method, and no statistically significant difference was found. The proposed method was assessed for greenness quantitatively and qualitatively using the Green Analytical Procedure Index (GAPI) and Analytical GREEnness metric (AGREE) as new greenness assessment tools.

The Tunable Parameters of Graphene-Based Biosensors.

Graphene-based surface plasmon resonance (SPR) biosensors have emerged as a promising technology for the highly sensitive and accurate detection of biomolecules. This study presents a comprehensive theoretical analysis of graphene-based SPR biosensors, focusing on configurations with single and bimetallic metallic layers. In this study, we investigated the impact of various metallic substrates, including gold and silver, and the number of graphene layers on key performance metrics: sensitivity of detection, detection accuracy, and quality factor. Our findings reveal that configurations with graphene first supported on gold exhibit superior performance, with sensitivity of detection enhancements up to 30% for ten graphene layers. In contrast, silver-supported configurations, while demonstrating high sensitivity, face challenges in maintaining detection accuracy. Additionally, reducing the thickness of metallic layers by 30% optimizes light coupling and enhances sensor performance. These insights highlight the significant potential of graphene-based SPR biosensors in achieving high sensitivity of detection and reliability, paving the way for their application in diverse biosensing technologies. Our findings pretend to motivate future research focusing on optimizing metallic layer thickness, improving the stability of silver-supported configurations, and experimentally validating the theoretical findings to further advance the development of high-performance SPR biosensors.

Carbon Nanocomposites-based Electrochemical Sensors and Biosensors for Biomedical Diagnostics.

Detection of emergent biomolecules or biomarkers remains crucial for early diagnosis in advancing healthcare monitoring and biomedicine. The possibility for rapid detection, real-time monitoring, high sensitivity, low detection limit, good selectivity, and low cost is central, among other significant issues for advancing point-of-care diagnosis. Carbon-based nanocomposites have been employed as sensing materials for various biomarkers due to their high surface-to-volume ratio, high electrical conductivity, chemical stability, and biocompatibility. The carbon nanomaterials, such as carbon nanotubes (CNTs), graphene (GR), carbon quantum dots (CQDs), carbon fibres (CFs), and their nanocomposites have broadly integrated with numerous sensing electrode materials for the detection of biomarkers under various experimental settings. The present review includes the recent advances in the development of carbon nanomaterials-based electrochemical sensors and biosensors for biomedical applications. The preparation, electrode preparation, effective utilization of carbon-derived nanomaterials, and their sensing performances towards numerous biomarkers have been highlighted. The state-of-the-merit, challenges, and prospects for designing carbon nanocomposites-based electrochemical sensor/biosensor platforms for biomedical diagnostics have also been described.

SERS and SE-FTIR platforms from plasmonic bismuth thin films for label-free multiplexed biomolecules detection

SERS and SE-FTIR platforms from plasmonic bismuth thin films for label-free multiplexed biomolecules detection

An Ultrasensitive Electrochemical Immunosensor for in Situ Detection of GABA in Plant Leaves

AbstractGamma‐aminobutyric acid (GABA) is involved in the signal transduction and metabolism of various substances in plants. Its in vivo detection in plants is of great importance for understanding its physiological role. In this study, an ultrasensitive electrochemical immunosensor is developed for in vivo detecting GABA in plants based on screen printed electrode (SPE) electrode. Gold nanoparticles (Au NP) was electrodeposited on the SPE to improve the conductivity of the electrode. Nanocomposite of ferrocene‐Carboxylated graphene oxide‐carboxylated multi‐walled carbon nanotubes (Fc‐GO‐MWCNT) was fabricated on the electrode to improve the electrochemical properties of the sensor, and Fc was used to generate electrochemical signals. Then polydopamine (PDA) was electropolymerized on the electrode to improve the electrochemical activity of the sensor and increase the loading amount of GABA antibody. The as‐prepared immunosensor shows the widest detection range of 10 fM to 10 mM, and lowest detection limit of 1.9 fM (S/N=3) for GABA. This immunosensor was applied for in vivo detecting GABA in the cucumber leaves under salt stress. Our sensor is the first electrochemical immunosensor for in vivo detecting GABA in plant. It proposes a new strategy for the development of immunosensor for in vivo detection of biomolecules in plants.

Bioinspired superwettable electrode towards sensitive detection of myocardial infarction-specific miRNA

The development of a reliable and sensitive method for the detection of myocardial infarction (MI)-specific miRNAs is of great significance in the diagnosis and management of MI. Electrochemical biosensors have emerged as a promising tool for the detection of biomolecules due to their high sensitivity, selectivity, simplicity of operation, and miniaturization. In order to further improve the sensitivity and selectivity of DNA electrochemical biosensors and meet the requirements of microRNA detection in biological samples, we fabricated a patterned superwettable gold electrode (PS-Au electrode) by mimicking the superwettable micropatterns of the desert beetle. Combining this bioinspired electrode with a DSN-assisted target recycling amplification strategy, we achieved ultrasensitive detection of myocardial infarction-specific miRNA-483 ranging from 10 aM to 100 fM with a low detection limit of 5.32 aM for miRNA-483. The electrochemical biosensor based on PS-Au electrode and DSN-assisted target recycling amplification (PSE-DTRA-EB) has good stability and specificity. Our study provides a new method for the ultrasensitive detection of MI-specific miRNAs, which may have important clinical applications in the diagnosis and prognosis of MI.

Detection of biomolecules from nano to atto-gram through plasmonic Elisa via tuning the catalyst

A simple and affordable plasmonic ELISA platform is demonstrated using silver nanocrystals as chromogens, and nanocatalysts in the place of enzyme. Apart from ultralow detection limitup to 10 molecules of human Immunoglobulin G (2.5 × 10−18 g/1.68 × 10−19 M), we exhibit very broad dynamic range covering 11-log which goes up to 100 × 10−9 g/6.72 × 10−9 M. To achieve this broad dynamic range and highly controlled standard deviation, nanocatalysts were tuned in terms of shape, size, metallic ratio, surface modification and other parameters. A comparative study is also done between traditional chromogen to independently developed new silver chromogen, and among different catalysts. Our results indicate plasmonic ELISA with small size nanocatalysts may become a very powerful detection strategy for biomolecules.

Hydrothermally in-situ grown MoS2 films over different conducting substrates as electrochemical-SERS biosensors

Detection of organic pollutants and biomolecules at very low concentrations is a great challenge for protecting the environment and diagnosis of human health. Noble metal nanomaterials have been employed as active surface-enhanced Raman spectroscopy (SERS) substrates for such detection but suffer with high cost. The two-dimensional (2D) transition-metal dichalcogenides (TMDs) can be used as cost-effective alternative SERS substrates for the detection of organic impurities and biomolecules. Here, we report the hydrothermally synthesized in-situ grown MoS2 films over conducting carbon paper (CCP) and fluorine-doped tin oxide (FTO) coated glass and used them as SERS substrates for the detection of Rhodamine 6G (R6G), vitamin B12 and bilirubin. We observe that hydrothermally in-situ grown MoS2 film over FTO coated glass (MoS2-FTO) shows a better SERS detection limit for studied analytes compared to the in-situ grown MoS2 film over conducting carbon paper (MoS2-CCP). We observe the detection of R6G, vitamin B12, and bilirubin with maximum enhancement factors of 2.42 × 106, 4.18 × 102, and 2.78 × 106, respectively, using MoS2-FTO as SERS substrate. Furthermore, we demonstrate the electrochemical-SERS (EC-SERS) activity of prepared SERS substrates. The MoS2-FTO shows a better EC-SERS signal as compared to MoS2-CCP due to the high conductivity (maximum charge transfer at oxidation potential), strong chemical adsorption, change of orientation, and density of the molecules on the surface of the substrate.

Combined matrix-assisted laser desorption/ionisation-mass spectrometry imaging with liquid chromatography-tandem mass spectrometry for observing spatial distribution of lipids in whole Caenorhabditis elegans.

Matrix-assisted laser desorption/ionisation-mass spectrometry imaging (MALDI-MSI) is a powerful label-free technique for biomolecule detection (e.g., lipids), within tissue sections across various biological species. However, despite its utility in many applications, the nematode Caenorhabditis elegans is not routinely used in combination with MALDI-MSI. The lack of studies exploring spatial distribution of biomolecules in nematodes is likely due to challenges with sample preparation. This study developed a sample preparation method for whole intact nematodes, evaluated using cryosectioning of nematodes embedded in a 10% gelatine solution to obtain longitudinal cross sections. The slices were then subjected to MALDI-MSI, using a RapifleX Tissuetyper in positive and negative polarities. Samples were also prepared for liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis using an Exploris 480 coupled to a HPLC Vanquish system to confirm the MALDI-MSI results. An optimised embedding method was developed for longitudinal cross-sectioning of individual worms. To obtain longitudinal cross sections, nematodes were frozen at -80°C so that all worms were rod shaped. Then, the samples were defrosted and transferred to a 10% gelatine matrix in a cryomold; the worms aligned, and the whole cryomold submerged in liquid nitrogen. Using MALDI-MSI, we were able to observe the distribution of lipids within C. elegans, with clear differences in their spatial distribution at a resolution of 5μm. To confirm the lipids from MALDI-MSI, age-matched nematodes were subjected to LC-MS/MS. Here, 520 lipids were identified using LC-MS/MS, indicating overlap with MALDI-MSI data. This optimised sample preparation technique enabled (un)targeted analysis of spatially distributed lipids within individual nematodes. The possibility to detect other biomolecules using this method thus laid the basis for prospective preclinical and toxicological studies on C. elegans.

A P+ pocket doped 4H–SiC Schottky barrier FET as highly sensitive label-free biosensor

In this paper, a 4H–SiC Schottky barrier field-effect transistor with a P+ doping Pocket based on dielectric modulation effect for label-free detection of biomolecules has been proposed. Upon optimization of the length and position of P+ doping pocket, the sensitivity of the biosensor achieves the maximum when it is located within the channel 1 nm away from the Schottky contact with a length of 5 nm. Simulations have been performed for different dielectric constants and biomolecules with different charge densities by Sentaurus TCAD. The results show that the new structure has an on-current sensitivity of 1.03 × 108, a maximum transconductance sensitivity of 6.24 × 107, a threshold voltage sensitivity of 65 mV, and an Ion/Ioff ratio sensitivity of 1.8 × 104 for neutral biomolecules with K = 12. In addition, the fill factor of the cavity and linearity of the proposed structure are considered in this paper. Further, the on-current sensitivity of our proposed structure is gauged against state of the art, which demonstrate a high sensitivity of our proposed biosensors. The smaller size and prominent sensitivity characteristics of the biosensor proposed in this paper have made it widely used in the field of biomedical detection that requires high integration and efficient detection.

Review on Synthesis of 2-(2-Hydroxyaryl) Benzothiazoles (HBT) for Excited-State Intra-molecular Proton Transfer (ESIPT)-Based Detection of Ions and Biomolecules.

In this review, we present a systematic and comprehensive summary of the recent developments in the synthetic strategies of 2-(2-hydroxyarylsubstituted)-benzothiazole (HBT) framework along with incorporation of various substituents on phenolic and benzothiazole rings which affect the emission process. The literature, spanning the years 2015-2024, on excited-state intramolecular proton transfer (ESIPT)-based studies of HBT derivatives comprising the effects of solvent polarity, substituents, and extended conjugation on fluorophores has been searched. ESIPT, intramolecular charge transfer, and aggregation-induced emissions enable these fluorescent probes to specifically interact with analytes, thereby altering their luminescence characteristics to achieve analyte detection. These fluorescent probes exhibit large Stokes shifts, high quantum yields, and excellent color transitions. Finally, the applications of HBTs as ESIPT-based fluorescent probes for the detection of cations, anions, and biomolecules have been summarized. We anticipate that this review will provide a comprehensive overview of the current state of research in this field and encourage researchers to develop novel ESIPT-based fluorophores with new applications.

Wide-energy programmable microwave plasma-ionization for high-coverage mass spectrometry analysis

Although numerous ambient ionization mass spectroscopy technologies have been developed over the past 20 years to address diverse analytical circumstances, a single-ion source technique that can handle all analyte types is still lacking. Here, a wide-energy programmable microwave plasma-ionization mass spectrometry (WPMPI-MS) system is presented, through which MS analysis can achieve high coverage of substances with various characteristics by digitally regulating the microwave energy. In addition, ionization energy can be rapidly scanned using programmable waveforms, enabling the simultaneous detection of biomolecules, heavy metals, non-polar molecules, etc., in seconds. WPMPI-MS performs well in analyzing real samples, rapidly analyzing nine toxicological standards in one drop of serum, and demonstrating good quantification and liquid chromatography coupling capability. The WPMPI-MS has also been used to detect soil extracts, solid pharmaceuticals, and landfill leachate, further demonstrating its robust analytical capabilities for real samples. The prospective uses of the technology in biological and chemical analysis are extensive, and it is anticipated to emerge as a viable alternative to commercially available ion sources.

Beta-Barrel Nanopores as Diagnostic Sensors: An Engineering Perspective.

Biological nanopores are ultrasensitive and highly attractive platforms for disease diagnostics, including the sequencing of viral and microbial genes and the detection of biomarkers and pathogens. To utilize biological nanopores as diagnostic sensors, they have been engineered through various methods resulting in the accurate and highly sensitive detection of biomarkers and disease-related biomolecules. Among diverse biological nanopores, the β-barrel-containing nanopores have advantages in nanopore engineering because of their robust structure, making them well-suited for modifications. In this review, we highlight the engineering approaches for β-barrel-containing nanopores used in single-molecule sensing for applications in early diagnosis and prognosis. In the highlighted studies, β-barrel nanopores can be modified by genetic mutation to change the structure; alter charge distributions; or add enzymes, aptamers, and protein probes to enhance sensitivity and accuracy. Furthermore, this review discusses challenges and future perspectives for advancing nanopore-based diagnostic sensors.

Gold nanoparticles-based biosensors: pioneering solutions for bacterial and viral pathogen detection-a comprehensive review.

Gold Nanoparticles (AuNPs) have gained significant attention in biosensor development due to their unique physical, chemical, and optical properties. When incorporated into biosensors, AuNPs offer several advantages, including a high surface area-to-volume ratio, excellent biocompatibility, ease of functionalization, and tunable optical properties. These properties make them ideal for the detection of various biomolecules, including proteins, nucleic acids, and bacterial and viral biomarkers. Traditional methods for detecting bacteria and viruses, such as RT-PCR and ELISA, often suffer from complexities, time consumption, and labor intensiveness. Consequently, researchers are continuously exploring novel devices to address these limitations and effectively detect a diverse array of infectious pathogenic microorganisms. In light of these challenges, nanotechnology has been instrumental in refining the architecture and performance of biosensors. By leveraging advancements in nanomaterials and strategies of biosensor fabrication the sensitivity and specificity of biosensors can be enhanced, enabling more precise detection of pathogenic bacteria and viruses. This review explores the versatility of AuNPs in detecting a variety of biomolecules, including proteins, nucleic acids, and bacterial and viral biomarkers. Furthermore, it evaluates recent advancements in AuNPs-based biosensors for the detection of pathogens, utilizing techniques such as optical biosensors, lateral flow immunoassays, colorimetric immunosensors, electrochemical biosensors, and fluorescence nanobiosensors. Additionally, the study discusses the existing challenges in the field and proposes future directions to improve AuNPs-based biosensors, with a focus on enhancing sensitivity, selectivity, and their utility in clinical and diagnostic applications.

Surface-Enhanced Raman Spectroscopy (SERS)-Based Sensors for Deoxyribonucleic Acid (DNA) Detection.

Surface-enhanced Raman spectroscopy (SERS) has emerged as a powerful technique for the detection and analysis of biomolecules due to its high sensitivity and selectivity. In recent years, SERS-based sensors have received significant attention for the detection of deoxyribonucleic acid (DNA) molecules, offering promising applications in fields such as medical diagnostics, forensic analysis, and environmental monitoring. This paper provides a concise overview of the principles, advancements, and potential of SERS-based sensors for DNA detection. First, the fundamental principles of SERS are introduced, highlighting its ability to enhance the Raman scattering signal by several orders of magnitude through the interaction between target molecules with metallic nanostructures. Then, the fabrication technologies of SERS substrates tailored for DNA detection are reviewed. The performances of SERS substrates previously reported for DNA detection are compared and analyzed in terms of the limit of detection (LOD) and enhancement factor (EF) in detail, with respect to the technical parameters of Raman spectroscopy (e.g., laser wavelength and power). Additionally, strategies for functionalizing the sensor surfaces with DNA-specific capture probes or aptamers are outlined. The collected data can be of help in selecting and optimizing the most suitable fabrication technology considering nucleotide sensing applications with Raman spectroscopy.

Conductive Polymer-Based Hydrogels for Wearable Electrochemical Biosensors.

Hydrogels are gaining popularity for use in wearable electronics owing to their inherent biomimetic characteristics, flexible physicochemical properties, and excellent biocompatibility. Among various hydrogels, conductive polymer-based hydrogels (CP HGs) have emerged as excellent candidates for future wearable sensor designs. These hydrogels can attain desired properties through various tuning strategies extending from molecular design to microstructural configuration. However, significant challenges remain, such as the limited strain-sensing range, significant hysteresis of sensing signals, dehydration-induced functional failure, and surface/interfacial malfunction during manufacturing/processing. This review summarizes the recent developments in polymer-hydrogel-based wearable electrochemical biosensors over the past five years. Initially serving as carriers for biomolecules, polymer-hydrogel-based sensors have advanced to encompass a wider range of applications, including the development of non-enzymatic sensors facilitated by the integration of nanomaterials such as metals, metal oxides, and carbon-based materials. Beyond the numerous existing reports that primarily focus on biomolecule detection, we extend the scope to include the fabrication of nanocomposite conductive polymer hydrogels and explore their varied conductivity mechanisms in electrochemical sensing applications. This comprehensive evaluation is instrumental in determining the readiness of these polymer hydrogels for point-of-care translation and state-of-the-art applications in wearable electrochemical sensing technology.

Temperature Effect Assessment on the Gate-All-Around Junctionless FET for Bio-Sensing Applications

The gate-all-around junctionless field-effect transistor (GAA JL FET)-based biosensor has recently attracted worldwide attention due to its good sensitivity to gate-all-around architecture and overall conduction mechanism. The effect of temperature usually affects the performance of transistors and sensors. Therefore, the impact of temperature on the 3D GAA JL FET-based biosensor has been investigated in this work. The dielectric modulation (DM) approach has been considered for including biomolecules. Consequently, the main proprieties of this biosensor have been investigated by ranging the temperature from 77[Formula: see text]K to 400[Formula: see text]K. The simulated results showed that the on-state current lowers as the temperature rises, but the off-state current increases. The off-current variation concerning the temperature is higher than the on-current change. Also, this type of biosensor appears to have a finer threshold voltage. Furthermore, the obtained results reveal that the current sensitivity is increased when ranging from temperature from 200[Formula: see text]K to 400[Formula: see text]K, and deteriorates for lower temperature values, like 100[Formula: see text]K and 77[Formula: see text]K. In addition, the GAA JL FET-based biosensor is more reliable for the detection of neutral biomolecules at high temperatures.

Advances in Label-Free Glucose Detection Using Self-Assembled Nanoparticles and Surface-Enhanced Raman Spectroscopy.

In the landscape of biomolecular detection, surface-enhanced Raman spectroscopy (SERS) confronts notable obstacles, particularly in the label-free detection of biomolecules, with glucose and other sugars presenting a quintessential challenge. This study heralds the development of a pioneering SERS substrate, ingeniously engineered through the self-assembly of nanoparticles of diverse sizes (Ag1@Ag2NPs). This configuration strategically induces 'hot spots' within the interstices of nanoparticles, markedly amplifying the detection signal. Rigorous experimental investigations affirm the platform's rapidity, precision, and reproducibility, and the detection limit of this detection method is calculated to be 6.62 pM. Crucially, this methodology facilitates nondestructive glucose detection in simulated samples, including phosphate-buffered saline and urine. Integrating machine learning algorithms with simulated serum samples, the approach adeptly discriminates between hypoglycemic, normoglycemic, and hyperglycemic states. Moreover, the platform's versatility extends to the detection and differentiation of monosaccharides, disaccharides, and methylated glycosides, underscoring its universality and specificity. Comparative Raman spectroscopic analysis of various carbohydrate structures elucidates the unique SERS characteristics pertinent to these molecules. This research signifies a major advance in nonchemical, label-free glucose determination with enhanced sensitivity via SERS, laying a new foundation for its application in precision medicine and advancing structural analysis in the sugar domain.

Dimeric and monomeric conformation of SARS-CoV-2 main protease: New technical approaches based on IR radiation

The main proteases Mpro are a group of highly conserved cysteine hydrolases in β-coronaviruses. They have been demonstrated to play an unavoidable role in viral replication, and consequently they have been suggested as key targets for treating coronavirus-caused infectious diseases, mainly from the COVID-19 epidemic. Since the most functional form for Mpro enzymatic activity is associated to its homodimer, compounds inhibiting dimerization should also inhibit catalytic activity. We show how PIR-SEIRA (Plasmonic Internal Reflection-Surface Enhanced InfraRed Absorption) spectroscopy can be a noteworthy technique to study proteins subtle structural variations associated to inhibitor binding. Nanoantennas arrays can selectively confine and enhance electromagnetic field via localized plasmonic resonances, thus promoting ultrasensitive detection of biomolecules in close proximity of nanoantenna arrays and enabling the effective investigation of protein monolayers. By adopting this approach, reflection measurements conducted under back illumination of nanoantennas allow to probe anchored protein monolayers, with minimum contribution of environmental buffer molecules. PIR-SEIRA spectroscopy on Mpro was carried out by ad hoc designed devices, resonating in the spectral region of Amide I and Amide II bands. We evaluated here the structure of anchored monomers and dimers in different buffered environment and in presence of a newly designed Mpro inhibitor. Experimental results show that dimerization is not associated to relevant backbone rearrangements of the protein at secondary structure level, and even if the compound inhibits the dimerization, it is not effective at breaking preformed dimers.