Noble metal nanostructures in optical biosensors: Basics, and their introduction to anti-doping detection

Chemometrics-aided surface-enhanced Raman spectrometric detection and quantification of GH and TE hormones in blood

Growth hormone (GH) and testosterone (TE) levels in blood are crucial indicators of human health and performance in clean sports. Deviations from normal levels can signal serious health issues, such as fertility problems, cancer, or pituitary tumors. Existing detection methods for these hormones are often costly, time-consuming, and lack portability. In this study, we explored the potential of Surface-Enhanced Raman Spectroscopy (SERS) in distinguishing blood samples from Sprague Dawley (SD) rats injected with exogenous GH, TE and both hormones from those not injected. Then, used artificial neural network (ANN) models trained, and validated in predicting levels of these hormones in blood. Blood samples from SD rats injected with GH, TE, both hormones, and non-injected rats were analyzed using the SERS method upon 785 nm laser excitation. The recorded Raman spectra from blood of GH and TE injected and non-injected rats displayed hormone-specific band intensity variations. Additionally, Principal Component Analysis (PCA) showed temporal changes in band intensities post-injection, suggesting hormone-induced biochemical alterations. In particular, Raman bands centered around 1378 cm⁻¹ for all groups, 658 cm⁻¹ for GH, and 798 cm⁻¹ for GH and TE displayed significant intensity variations. The ANN models, trained using PCA scores from blood samples with varied hormone concentrations, achieved high predictive accuracy with coefficients of determination (R² > 87.71%) and low root mean square error (RMSE < 0.6436). Elevated hormone levels were initially observed in injected rats, gradually declining over time, with results aligning closely to those obtained via ELISA kits. This work showed that the SERS method can provide rapid (~2 minutes), hormone-independent detection with minimal sample preparation. This approach demonstrated the SERS method's potential for rapid, reliable hormone detection and with customized calibration may be applied in sports doping control, clinical diagnostics, and broader biomedical research.

The Application of Machine Learning in Doping Detection

Detecting doping agents in sports poses a significant challenge due to the continuous emergence of new prohibited substances and methods. Traditional detection methods primarily rely on targeted analysis, which is often labor-intensive and is susceptible to errors. In response, machine learning offers a transformative approach to enhancing doping screening and detection. With its powerful data analysis capabilities, machine learning enables the rapid identification of patterns and features in complex compound data, increasing both the efficiency and the accuracy of detection. Moreover, when integrated with nontargeted metabolomics, machine learning can predict unknown metabolites, aiding the discovery of long-lasting biomarkers of doping. It also excels in classifying novel compounds, thereby reducing false-negative rates. As instrumental analysis and machine learning technologies continue to advance, the development of rapid, scalable, and highly efficient doping detection methods becomes increasingly feasible, supporting the pursuit of fairness and integrity in sports competitions.

Ultrasensitive SERS Detection of Five β-Blockers Achieved Using Chemometrics with a Two-Dimensional Substrate Formed by Large-Sized Ag@SiO2 Nanoparticles

We report on a surface-enhanced Raman scattering (SERS) platform for the detection of five beta-blockers (β-blockers): atenolol, esmolol, labetalol, sotalol, and propranolol. Key to this platform was a two-dimensional substrate formed by self-assembling large Ag@SiO2 nanoparticles (Ag@SiO2 NPs) on a silicon wafer. The close arrangement of these large nanoparticles on the surface generated a strong and uniform electromagnetic field, which enhanced SERS signal intensity for the detection of small amounts of the target molecules. The intensities of characteristic peaks of the five β-blocker drugs increased linearly with the increase of their concentrations in the range of 10-5 to 10-8 mol/L. The detection limits were 10-10 mol/L for propranolol, 10-9 mol/L for atenolol, labetalol, and sotalol, and 10-8 mol/L for esmolol. Determination of these five β-blocker drugs added to human urine samples, using a portable Raman spectroscopy instrument, showed quantitative recovery (93-101%). Principal component analysis (PCA) and hierarchical cluster analysis (HCA) of SERS spectral data improved the differentiation among these five β-blockers. This study highlights the potential of the developed SERS platform for rapid, on-site detection of illicit drugs and for antidoping screening.

The Evolution of Illicit-Drug Detection: From Conventional Approaches to Cutting-Edge Immunosensors-A Comprehensive Review

The increasing use of illicit drugs has become a major global concern. Illicit drugs interact with the brain and the body altering an individual's mood and behavior. As the substance-of-abuse (SOA) crisis continues to spread across the world, in order to reduce trafficking and unlawful activity, it is important to use point-of-care devices like biosensors. Currently, there are certain conventional detection methods, which include gas chromatography (GC), mass spectrometry (MS), surface ionization, surface-enhanced Raman spectroscopy (SERS), surface plasmon resonance (SPR), electrochemiluminescence (ECL), high-performance liquid chromatography (HPLC), etc., for the detection of abused drugs. These methods have the advantage of high accuracy and sensitivity but are generally laborious, expensive, and require trained operators, along with high sample requirements, and they are not suitable for on-site drug detection scenarios. As a result, there is an urgent need for point-of-care technologies for a variety of drugs that can replace conventional techniques, such as a biosensor, specifically an immunosensor. An immunosensor is an analytical device that integrates an antibody-based recognition element with a transducer to detect specific molecules (antigens). In an immunosensor, the highly selective antigen-antibody interaction is used to identify and quantify the target analyte. The binding event between the antibody and antigen is converted by the transducer into a measurable signal, such as electrical, optical, or electrochemical, which corresponds to the presence and concentration of the analyte in the sample. This paper provides a comprehensive overview of various illicit drugs, the conventional methods employed for their detection, and the advantages of immunosensors over conventional techniques. It highlights the critical need for on-site detection and explores emerging point-of-care testing methods. The paper also outlines future research goals in this field, emphasizing the potential of advanced technologies to enhance the accuracy, efficiency, and convenience of drug detection.

Nanomaterial-Based Sensors for Coumarin Detection

Sensors are widely used owing to their advantages including excellent sensing performance, user-friendliness, portability, rapid response, high sensitivity, and specificity. Sensor technologies have been expanded rapidly in recent years to offer many applications in medicine, pharmaceuticals, the environment, food safety, and national security. Various nanomaterial-based sensors have been developed for their exciting features, such as a powerful absorption band in the visible region, excellent electrical conductivity, and good mechanical properties. Natural and synthetic coumarin derivatives are attracting attention in the development of functional polymers and polymeric networks for their unique biological, optical, and photochemical properties. They are the most abundant organic molecules in medicine because of their biological and pharmacological impacts. Furthermore, coumarin derivatives can modulate signaling pathways that affect various cellular processes. This review covers the discovery of coumarins and their derivatives, the integration of nanomaterial-based sensors, and recent advances in nanomaterial-based sensing for coumarins. This review also explains how sensors work, their types, their pros and cons, and sensor studies for coumarin detection in recent years.

Localized surface plasmon resonance sensing of Trenbolone acetate dopant using silver nanoparticles

In this work, localized surface plasmon resonance (LSPR) sensing as applicable in the detection of Trenbolone acetate dopant is demonstrated. We show that the LSPR of the Trenbolone acetate/silver nanoparticle (Tren Ac/AgNPs) complex is sensitive to changes in the adsorbent concentration. The results show an average redshift of + 18 nm in the LSPR peak with variations in intensity and broadening behavior of the LSPR band of the Tren Ac/AgNPs complex. AgNPs were synthesized using laser ablation in liquid (LAL) technique with water as the solvent. UV-Vis spectroscopy was used for absorbance measurements and particle size and morphology were monitored using scanning electron microscopy (SEM). The aggregation behavior of the Tren Ac/AgNPs complex was monitored using energy-dispersive X-ray spectroscopy (EDS). Molecular Electrostatic Potential (MEP) and the HOMO-LUMO orbitals of the optimized Trenbolone acetate structure were obtained using Density Function Theory (DFT). The molecule was optimized at the B3LYP level of theory using the 6-311 basis set carried out using the Gaussian 09 software package. The results showed that O2- is Trenbolone acetate's active site that would interact with Ag+ to form a complex that would influence the plasmon behavior. The results presented in this work demonstrate the feasibility of LSPR for anabolic androgenic steroid detection.

Plasmonic Fluorescence Sensors in Diagnosis of Infectious Diseases

The increasing demand for rapid, cost-effective, and reliable diagnostic tools in personalized and point-of-care medicine is driving scientists to enhance existing technology platforms and develop new methods for detecting and measuring clinically significant biomarkers. Humanity is confronted with growing risks from emerging and recurring infectious diseases, including the influenza virus, dengue virus (DENV), human immunodeficiency virus (HIV), Ebola virus, tuberculosis, cholera, and, most notably, SARS coronavirus-2 (SARS-CoV-2; COVID-19), among others. Timely diagnosis of infections and effective disease control have always been of paramount importance. Plasmonic-based biosensing holds the potential to address the threat posed by infectious diseases by enabling prompt disease monitoring. In recent years, numerous plasmonic platforms have risen to the challenge of offering on-site strategies to complement traditional diagnostic methods like polymerase chain reaction (PCR) and enzyme-linked immunosorbent assays (ELISA). Disease detection can be accomplished through the utilization of diverse plasmonic phenomena, such as propagating surface plasmon resonance (SPR), localized SPR (LSPR), surface-enhanced Raman scattering (SERS), surface-enhanced fluorescence (SEF), surface-enhanced infrared absorption spectroscopy, and plasmonic fluorescence sensors. This review focuses on diagnostic methods employing plasmonic fluorescence sensors, highlighting their pivotal role in swift disease detection with remarkable sensitivity. It underscores the necessity for continued research to expand the scope and capabilities of plasmonic fluorescence sensors in the field of diagnostics.

How new nanotechnologies are changing the opioid analysis scenery? A comparison with classical analytical methods

Opioids such as heroin, fentanyl, raw opium, and morphine have become a serious threat to the world population in the recent past, due to their increasing use and abuse. The detection of these drugs in biological samples is usually carried out by spectroscopic and/or chromatographic techniques, but the need for quick, sensitive, selective, and low-cost new analytical tools has pushed the development of new methods based on selective nanosensors, able to meet these requirements. Modern sensors, which utilize "next-generation" technologies like nanotechnology, have revolutionized drug detection methods, due to easiness of use, their low cost, and their high sensitivity and reliability, allowing the detection of opioids at trace levels in raw, pharmaceutical, and biological samples (e.g. blood, urine, saliva, and other biological fluids). The peculiar characteristics of these sensors not only have allowed on-site analyses (in the field, at the crime scene, etc.) but also they are nowadays replacing the gold standard analytical methods in the laboratory, even if a proper method validation is still required. This paper reviews advances in the field of nanotechnology and nanosensors for the detection of commonly abused opioids both prescribed (i.e. codeine and morphine) and illegal narcotics (i.e. heroin and fentanyl analogues).

A Review of Recent Progress in Drug Doping and Gene Doping Control Analysis

The illicit utilization of performance-enhancing substances, commonly referred to as doping, not only infringes upon the principles of fair competition within athletic pursuits but also poses significant health hazards to athletes. Doping control analysis has emerged as a conventional approach to ensuring equity and integrity in sports. Over the past few decades, extensive advancements have been made in doping control analysis methods, catering to the escalating need for qualitative and quantitative analysis of numerous banned substances exhibiting diverse chemical and biological characteristics. Progress in science, technology, and instrumentation has facilitated the proliferation of varied techniques for detecting doping. In this comprehensive review, we present a succinct overview of recent research developments within the last ten years pertaining to these doping detection methodologies. We undertake a comparative analysis, evaluating the merits and limitations of each technique, and offer insights into the prospective future advancements in doping detection methods. It is noteworthy that the continual design and synthesis of novel synthetic doping agents have compelled researchers to constantly refine and innovate doping detection methods in order to address the ever-expanding range of covertly employed doping agents. Overall, we remain in a passive position for doping detection and are always on the road to doping control.

MoS2-ZnO Nanocomposite Mediated Immunosensor for Non-Invasive Electrochemical Detection of IL8 Oral Tumor Biomarker

In order to support biomolecule attachment, an effective electrochemical transducer matrix for biosensing devices needs to have many specialized properties, including quick electron transfer, stability, high surface area, biocompatibility, and the presence of particular functional groups. Enzyme-linked immunosorbent assays, gel electrophoresis, mass spectrometry, fluorescence spectroscopy, and surface-enhanced Raman spectroscopy are common techniques used to assess biomarkers. Even though these techniques provide precise and trustworthy results, they cannot replace clinical applications because of factors such as detection time, sample amount, sensitivity, equipment expense, and the need for highly skilled individuals. For the very sensitive and targeted electrochemical detection of the salivary oral cancer biomarker IL8, we have created a flower-structured molybdenum disulfide-decorated zinc oxide composite on GCE (interleu-kin-8). This immunosensor shows very fast detection; the limit of detection (LOD) for interleukin-8 (IL8) detection in a 0.1 M phosphate buffer solution (PBS) was discovered to be 11.6 fM, while the MoS₂/ZnO nanocomposite modified glassy carbon electrode (GCE) demonstrated a high catalytic current linearly from 500 pg to 4500 pg mL^-1 interleukin-8 (IL8). Therefore, the proposed biosensor exhibits excellent stability, high accuracy sensitivity, repeatability, and reproducibility and shows the acceptable fabrication of the electrochemical biosensors to detect the ACh in real sample analysis.

Nanomaterials for optical biosensors in forensic analysis

Biosensors are compact analytical devices capable of transducing a biological interaction event into a measurable signal outcome in real-time. They can provide sensitive and affordable analysis of samples without the need for additional laboratory equipment or complex preparation steps. Biosensors may be beneficial for forensic analysis as they can facilitate large-scale high-throughput, sensitive screening of forensic samples to detect target molecules that are of high evidential value. Nanomaterials are gaining attention as desirable components of biosensors that can enhance detection and signal efficiency. Biosensors that incorporate nanomaterials within their design have been widely reported and developed for medical purposes but are yet to find routine employment within forensic science despite their proven potential. In this article, key examples of the use of nanomaterials within optical biosensors designed for forensic analysis are outlined. Their design and mechanism of detection are both considered throughout, discussing how nanomaterials can enhance the detection of the target analyte. The critical evaluation of the optical biosensors detailed within this review article should help to guide future optical biosensor design via the incorporation of nanomaterials, for not only forensic analysis but alternative analytical fields where such biosensors may prove a valuable addition to current workflows.

Green chemistry and coronavirus

The novel coronavirus pandemic has rapidly spread around the world since December 2019. Various techniques have been applied in identification of SARS-CoV-2 or COVID-19 infection including computed tomography imaging, whole genome sequencing, and molecular methods such as reverse transcription polymerase chain reaction (RT-PCR). This review article discusses the diagnostic methods currently being deployed for the SARS-CoV-2 identification including optical biosensors and point-of-care diagnostics that are on the horizon. These innovative technologies may provide a more accurate, sensitive and rapid diagnosis of SARS-CoV-2 to manage the present novel coronavirus outbreak, and could be beneficial in preventing any future epidemics. Furthermore, the use of green synthesized nanomaterials in the optical biosensor devices could leads to sustainable and environmentally-friendly approaches for addressing this crisis.

Rapid and selective detection of recombinant human erythropoietin in human blood plasma by a sensitive optical sensor

Recombinant human erythropoietin (rHuEPO) is an important hormone drug that is used to treat several medical conditions. It is also frequently abused by athletes as a performance enhancing agent at sporting events. The time window of the rHuEPO in blood is short. Therefore, the rapid detection of rHuEPO use/abuse at points of care and in sports requires a selective analytical method and a sensitive sensor. Herein, we present a highly selective method for the rapid detection of rHuEPO in human blood plasma by a sensitive optical sensor. rHuEPO is selectively extracted from human blood plasma by a target-specific extractor chip and converted into a biothiol by reducing its disulfide bond structure. The formed biothiol reacts with a water soluble (E)-1-((6-methoxybenzo[d]thiazole-2-yl)diazenyl)naphthalene-2,6-diolHg(ii) (BAN-Hg) optical sensor and causes its rapid decomposition. This leads to a rapid change in the sensor color from blue to pink that can be observed by the naked eye. The optical sensor was used to quantify rHuEPO in the concentration range 1 × 10-8 M to 1 × 10-12 M by UV-Vis spectroscopy. For the screening of blood plasma, an EPO-specific extractor chip was synthesized and used to selectively extract the protein from the biological matrix prior to its conversion into biothiol and quantification by the optical sensor. Since many proteins have a disulfide bond structure, the new method has strong potential for their rapid sensitive and selective detection by the BAN-Hg sensor and UV-Vis spectroscopy.

Designing caps for colloidal Au nanoparticles

The plasmonic property of a nanostructure is highly dependent on its morphology, but there are few methods for appending a domain as the "functional group" or modifier. As a means of modulating plasmonic properties, we create and modulate Au hats on Au nanoparticles, including mortarboards, beret hats, helmets, crowns, antler hats and antenna hats. The structural control arises from the active surface growth as a result of dynamic competition between ligand absorption and metal deposition. It allows the continuous tuning of hat morphologies, from the facet-controlled growth of mortarboards, to the spreading-favored growth of beret hats and helmets, and to the vertical growth of pillars in crowns, antler hats and antenna hats. Among these plasmonic nanostructures, the mortarboards show excellent SERS enhancement of 8.1 × 105, which is among the best in colloidal nanostructures; and the antler hats show the photothermal conversion efficiency of 66.2%, which compares favorably with the literature reports.

Recent progress on developing of plasmon biosensing of tumor biomarkers: Efficient method towards early stage recognition of cancer

Cancer is the second most extended disease with an improved death rate over the past several time. Due to the restrictions of cancer analysis methods, the patient's real survival rate is unknown. Therefore, early stage diagnosis of cancer is crucial for its strong detection. Bio-analysis based on biomarkers may help to overcome the problem Biosensors with high sensitivity and specificity, low-cost, high analysis speed and minimum limit of detection are practical alternatives for laboratory tests. Surface plasmon resonance (SPR) is reaching a maturity level sufficient for their application in detection and determination cancer biomarkers in clinical samples. This review discusses main concepts and performance characteristics of SPR biosensor. Mainly, it focuses on newly emerged enhanced SPR biosensors towards high-throughput and ultrasensitive screening of cancer biomarkers such as PSA, α-fetoprotein, CEA, CA125, CA 15-3, HER2, ctDNA, ALCAM, hCG, VEGF, TNF, Interleukin, IFN-γ, CD24, CD44, Ferritin, COLIV using labeling processes with focusing on the future application in biomedical research and clinical diagnosis. This article reviews current status of the field, showcasing a series of early successes in the application of SPR for clinical bioanalysis of cancer related biomolecules and detailing a series of considerations regarding sensing schemes, exposing issues with analysis in biofluids, while providing an outlook of the challenges currently associated with plasmonic materials, bioreceptor selection, microfluidics, and validation of a clinical bioassay for applying SPR biosensors to clinical samples. Research opportunities are proposed to further advance the field and transition SPR biosensors from research proof-of-concept stage to actual clinical usage.

Cocaine by-product detection with metal oxide semiconductor sensor arrays

A range of n-type and p-type metal oxide semiconductor gas sensors based on SnO₂ and Cr₂O₃ materials have been modified with zeolites H-ZSM-5, Na-A and H–Y to create a gas sensor array able to successfully detect a cocaine by-product, methyl benzoate, which is commonly targeted by detection dogs. Exposure to vapours was carried out with eleven sensors. Upon data analysis, four of these that offered promising qualities for detection were subsequently selected to understand whether machine learning methods would enable successful and accurate classification of gases. The capability of discrimination of the four sensor array was assessed against nine different vapours of interest; methyl benzoate, ethane, ethanol, nitrogen dioxide, ammonia, acetone, propane, butane, and toluene. When using the polykernel function (C = 200) in the Weka software – and just five seconds into the gas injection – the model was 94.1% accurate in successfully classifying the data. Although further work is necessary to bring the sensors to a standard of detection that is competitive with that of dogs, these results are very encouraging because they show the potential of metal oxide semiconductor sensors to rapidly detect a cocaine by-product in an inexpensive way.

Metal oxide semiconductor gas sensors based on SnO₂ and Cr₂O₃ were modified with zeolites H-ZSM-5, Na-A and H–Y to create a gas sensor array to detect cocaine by-product, methyl benzoate. SVMs were later used with a 4 sensor array to classify 9 gases of interest.

Biogenic Metal Nanoparticles: A New Approach to Detect Life on Mars?

Metal nanoparticles (MNPs) have been extensively studied. They can be produced via different methods (physical, chemical, or biogenic), but biogenic synthesis has become more relevant, mainly for being referred by many as eco-friendly and more advantageous than others. Biogenic MNPs have been largely used in a wide variety of applications, from industry, to agriculture, to health sectors, among others. Even though they are increasingly researched and used, there is still space for exploring further applications and increasing their functionality and our understanding of their synthesis process. Here, we provide an overview of MNPs and biogenic MNPs, and we analyze the potential application of their formation process to astrobiology and the detection of life on Mars and other worlds. According to current knowledge, we suggest that they can be used as potential biosignatures in extra-terrestrial samples. We present the advantages and disadvantages of this approach, suggest further research, and propose its potential use for the search for life in future space exploration.

Development of a methodology for reversible chemical modification of silicon surfaces with application in nanomechanical biosensors

Hypervalent tellurium compounds have a particular reactivity towards thiol compounds which are related to their biological properties. In this work, this property was assembled to tellurium-functionalized surfaces. These compounds were used as linkers in the immobilization process of thiolated biomolecules (such as DNA) on microcantilever surfaces. The telluride derivatives acted as reversible binding agents due to their redox properties, providing the regeneration of microcantilever surfaces and allowing their reuse for further biomolecules immobilizations, recycling the functional surface. Initially, we started from the synthesis of 4-((3-((4-methoxyphenyl) tellanyl) phenyl) amino)-4-oxobutanoic acid, a new compound, which was immobilized on a silicon surface. In nanomechanical systems, the detection involved a hybridization study of thiolated DNA sequences. Fluorescence microscopy technique was used to confirm the immobilization and removal of the telluride-DNA system and provided revealing results about the potentiality of applying redox properties to chalcogen derivatives at surfaces.

Irreversible photo-Fenton-like triggered agglomeration of ultra-small gold nanoparticles capped with crosslinkable materials

A photo-Fenton-like process can promote the agglomeration and LSPR red-shifting of ultra-small gold nanoparticles by triggering a crosslink-degradation pathway that involves the surface coating, Fe(iii)-citrate and hydrogen peroxide. Applications may range from controlled photo-deposition of active materials to asynchronous sensing technologies to light-focused microfabrication.

Photoluminescent functionalized carbon dots for CRISPR delivery: synthesis, optimization and cellular investigation

Gene therapy using clustered regularly interspaced short palindromic repeat plasmids (pCRISPR) reduces mistakes in gene editing and prevents engendering integrational mutagenesis that has been seen in available genome engineering technologies. Developing an ideal and traceable nanocarrier, which can accurately and efficiently transfer this complex into the cytosol and which facilitates the journey towards the nucleus, is a fascinating area of research. Polyethylenimine (PEI) functionalized carbon dots (CD-PEI) were fabricated by one-step microwave assisted pyrolysis with an average size around 3 nm. This CD-PEI showed good potential for intracellular delivery of genetic materials (∼70%). Also, this CD-PEI with passive surface modification with low molecular PEI (2 kDa) has a very high quantum yield, as high as 40% with low cytotoxicity. The expression rate of the pCRISPR was around 15% in the HEK-293 cell which is comparable with the pristine PEI. Furthermore, the CD-PEI demonstrated good properties, such as high quantum yield, biocompatibility and tunable emission wavelengths, suggesting the potential application of photoluminescent functionalized CDs as a suitable, traceable nanocarrier for CRISPR delivery.

Surface-Enhanced Raman Scattering Spectroscopy and Microfluidics: Towards Ultrasensitive Label-Free Sensing

Raman scattering and surface-enhanced Raman scattering (SERS) spectroscopy have demonstrated their potential as ultrasensitive detection techniques in the past decades. Specifically, and as a result of the flourishing of nanotechnology, SERS is nowadays one of the most powerful sensing techniques, not only because of the low detection limits that it can achieve, but also for the structural information that it offers and its capability of multiplexing. Similarly, microfluidics technology is having an increased presence not only in fundamental research, but also in the industry. The latter is because of the intrinsic characteristics of microfluidics, being automation, high-throughput, and miniaturization. However, despite miniaturization being an advantage, it comes together with the need to use ultrasensitive techniques for the interrogation of events happening in extremely small volumes. The combination of SERS with microfluidics can overcome bottlenecks present in both technologies. As a consequence, the integration of Raman and SERS in microfluidics is being investigated for the label-free biosensing of relevant research challenges.

Sensors Based on Bio and Biomimetic Receptors in Medical Diagnostic, Environment, and Food Analysis

Analytical chemistry is now developing mainly in two areas: automation and the creation of complexes that allow, on the one hand, for simultaneously analyzing a large number of samples without the participation of an operator, and on the other, the development of portable miniature devices for personalized medicine and the monitoring of a human habitat. The sensor devices, the great majority of which are biosensors and chemical sensors, perform the role of the latter. That last line is considered in the proposed review. Attention is paid to transducers, receptors, techniques of immobilization of the receptor layer on the transducer surface, processes of signal generation and detection, and methods for increasing sensitivity and accuracy. The features of sensors based on synthetic receptors and additional components (aptamers, molecular imprinted polymers, biomimetics) are discussed. Examples of bio- and chemical sensors' application are given. Miniaturization paths, new power supply means, and wearable and printed sensors are described. Progress in this area opens a revolutionary era in the development of methods of on-site and in-situ monitoring, that is, paving the way from the "test-tube to the smartphone".