Sensor Elements Research Articles

A Universal Method for Fingerprinting Multiplexed Bacteria: Evolving Pruned Sensor Arrays via Machine Learning-Driven Combinatorial Group-Specificity Strategy.

Array-based sensing technology holds immense potential for discerning the intricacies of biological systems. Nevertheless, developing a universal strategy for simultaneous identification of diverse types of multianalytes and meeting the diagnostic needs of a range of multiclassified clinical diseases poses substantial challenges. Herein, we introduce a combination method for constructing sensor arrays by assembling two types of group-specific elements. Such a method enables the rapid generation of a library of 100 sensing units, each with dual bacterial targeting capabilities. By employing a three-step screening strategy optimized by machine learning algorithms, various optimal five-element arrays were rapidly obtained for diverse clinical infectious models. Moreover, the pruned arrays successfully identified disparate mixing ratios and quantitative detection of clinically prevalent bacterial strains. Optimized through nine multiclassification algorithms, the top-performing multilayer perceptron (MLP) model demonstrated impressive recognition capabilities, achieving 100% accuracy for diagnosing clinical urinary tract infection (UTI) and 99.4% accuracy for clinical sepsis detection in the test models we collected. Such a combinatorial library construction and screening process should be standard and provides insights into successfully generating powerful high-recognition sensor elements and configuring them into highly discriminative mini-sensor arrays.

Microstructured Liquid Metal-Based Embedded-Type Sensor Array for Curved Pressure Mapping.

Human hands can envelop the surface of an object and recognize its shape through touch. However, existing stretchable haptic sensors exhibit limited flexibility and stability to detect pressure during deformation, while also solely achieving recognition of planar objects. Inspired by the structure of skin tissue, an embedded construction-enabled liquid metal-based e-skin composed of a liquid metal microstructured electrode (LM-ME) array is fabricated for curved pressure mapping. The embedded LM-ME-based sensor elements are fabricated by using femtosecond laser-induced micro/nanostructures and water/hydrogel assisted patterning method, which enables high sensitivity (7.42kPa-1 in the range of 0-0.1kPa) and high stability through an interlinked support isolation structure for the sensor units. The sensor array with a high interfacial toughness of 1328Jm-2 can maintain pressure sensation under bending and stretching conditions. Additionally, the embedded construction and laser-induced bumps effectively reduce crosstalk from 58 to 7.8% compared to conventional flexible sensors with shared surfaces. The stretchable and mechanically stable sensor arrays possess shape-adaptability that enables pressure mapping on non-flat surfaces, which has great potential for object recognition in robotic skins and human-computer interaction.

Method to Generate Chlorine Dioxide Gas In Situ for Sterilization of Automated Incubators.

Pharmaceutical preclinical tests using cell cultures are nowadays commonly automated. Incubator microbial contaminations impact such tests. Chlorine dioxide (ClO2) is widely used in aqueous solutions. However, a gaseous form, such as chlorine dioxide gas (gClO2), can effectively access unreachable spaces, such as closed cell culture incubators. Steam sterilization requires a temperature rise to at least 121 °C, thus limiting the possibility of automation elements for sensors and actuators. gClO2 sterilization is an ambient-temperature sterilization method. This article aims to demonstrate that gClO2 generated from solid powder tablets is efficient for sterilizing incubators and can be automated. We selected (i) Bacillus subtilis strain, (ii) Saccharomyces cerevisiae, and (iii) T7 phages as representatives for (i) bacteria, (ii) fungi, and (iii) viruses for each domain to evaluate the sterilization efficiency. This study demonstrated that gClO2 can be generated inside the incubator from a solid powder tablet without specific equipment and can effectively fight biological proxies in 15 min. After 30 sterilization cycles, the actuators and sensors mounted inside the incubator were still operating. Our proposed sterilization method seems to be generally applicable for automated in situ sterilization of incubators and medical robots.

Membrane piezoelectric MDS-actuator with a flat double spiral of interacting electrodes

A schematic diagram and mathematical model of functioning of a new piezoelectric membrane (MDS) actuator with double spiral (DS) electrodes on the upper and/or lower surfaces of a thin piezoelectric layer with axisymmetric and periodic (with a small period) in radial coordinate mutual reversed electric polarization are presented. The polarization of the layer was realized as a result of connecting the polarizing electric voltage of the appropriate value to the outputs of the double spirals of the electrodes. The electrodes of each (upper and lower) double spiral of the MDS-actuator are made in the form of electrodeposited ribbon coatings on the surfaces of the piezoelectric layer in close proximity to each other (due to the small spiral pitch) to create high values of electric field strength along the lines of force in localized areas of the piezoelectric layer between them when an alternating or constant control electric voltage is connected to the electrodes, in particular, with positive and negative values of the electrical potentials. Importantly, the electric field force lines and, as a consequence, the polarization of the piezoelectric layer of the MDS actuator are oriented mainly along (i.e. towards or against) the radial coordinate of the membrane, in contrast to many conventional actuator schemes. The results of numerical modeling for a circular elastic membrane with piezoelectric actuators installed on its upper and lower surfaces confirmed the effectiveness of the proposed piezoelectric MDS-actuator when it functions according to the “bimorph” scheme, including the use of the proposed new structural element (section) – a piezoelectric “compression ring” MDS at various geometric and control parameters. The effect of a significant increase in the membrane deflection with installed piezoelectric MDS-actuators compared to the use of traditional homogeneous plate piezoelectric actuators of bimorph type for different conditions of the membrane fixation, in particular, stationary (rigid) fixation of its center is revealed. For a hybrid piezoelectric MDS-actuator including independent concentric round and circular (i.e. “compression ring”) sections, the non-monotonic nature and numerical analysis of the nonlinear dependence of the largest deflection at the center of a hinge-immobile membrane fixed at the edge on the ratio of the radii of its round and circular MDS sections were revealed. The cases in which the effect of the “compression ring” is manifested, i.e. when the maximum deflection of a membrane with the “compression ring” exceeds the best possible value of the deflection of this membrane without its use in the traditional “bimorph” scheme, are identified. The new piezoelectric MDS-actuator can be used in micromechanics, controlled optics, sensor technology, acoustics, in particular, in the manufacture of piezoelectric acoustic or sensor elements of membrane type, electromechanical transducers for vibration energy collection.

Fabrication and characterization of inkjet-printed interdigitated electrodes for non-faradaic electrochemical detection of uromodulin in urine

This work describes the simulation, design, and fabrication of an inkjet-printed impedance biosensor for uromodulin which is a urine biomarker for kidney disease. The interdigitated electrodes (IDE) were fabricated through inkjet printing of silver ink on polyethylene terephthalate (PET) substrate and subsequently passivated with SU-8 for non-faradaic measurements. We functionalized the passivated IDE with biotin-streptavidin complex and uromodulin antibody to detect uromodulin (6.75 μg/ml-100 μg/ml). The measured impedance due to uromodulin immobilized from artificial urine samples showed a 27.4 % change in impedance magnitude per μg/ml of uromodulin at 150 Hz (log scale). The limit of detection achieved is 25 ng/ml. The sensor demonstrated specificity to uromodulin when measured against albumin, which is another protein biomarker present in the urine. These results highlight the possibility of implementing non-faradaic impedance measurements using a passivated IDE as the sensor element. It also promotes the sensor fabrication method of inkjet printing. The sensor concept shows the implementation potential of IDE as a single-use-sensor for point-of-care applications.

Ontology of Addressed Fiber Bragg Structures as a New Type of Sensor Elements

Ontology of Addressed Fiber Bragg Structures as a New Type of Sensor Elements

Unconventional coil shape design of eddy current sensors and the effect of shape parameters on the micro/nano-scale metal film thickness measurement performance

Abstract The thickness of metal film is a critical parameter, especially in micro/nano-manufacturing, where high-precision measurement is essential. The eddy current method, a non-destructive testing technique, is well-suited for in-situ measurement of micro/nano-scale metal film thickness due to its superior performance. However, enhancing the measurement capabilities of eddy current sensors remains a significant challenge. In practical applications, thickness sensitivity and spatial resolution are two key performance indicators of eddy current sensors, and improving both simultaneously is difficult. While the sensitive element (coil) of an eddy current sensor has a substantial impact on thickness sensitivity, its effect on spatial resolution has received less attention.
This study establishes an eddy current coil model based on electromagnetic field theory, defining both thickness sensitivity and spatial resolution in the context of micro/nano-scale metal film thickness measurement. Two unconventional coil shapes are introduced, contrasting with the traditional cylindrical design, to investigate the influence of coil shape parameters, specifically the spatial distribution of the coil turns, on the key performance indicators. Simulation results are corroborated through experimental validation. Based on a series of calculations and analyses, an optimization method for coil shape parameters is proposed using a defined comparison factor that balances both thickness sensitivity and spatial resolution, which offers a promising approach for improving coil shape design.

Online Quality Control of Powder Bed Fusion with High-Resolution Eddy Current Testing Inductive Sensor Arrays.

This paper presents the development of a novel eddy current array (ECA) system for real-time, layer-by-layer quality control in powder bed fusion (PBF) additive manufacturing. The system is integrated into the recoater of a PBF machine to provide spatially resolved electrical conductivity imaging of the manufactured part. The system features an array of 40 inductive sensors spaced at 1 mm pitch and is capable of performing a full array readout every 0.192 mm at 100 mm/s recoater speed. Array scalability was achieved through the careful selection of the electromagnetic configuration, miniaturized and seamlessly integrated sensor elements, and the use of advanced mixed signal processing techniques. Experimental validation was performed on stainless steel 316L parts, successfully detecting metallic structures and confirming system performance in both laboratory and real-time PBF environments. The prototype achieved a signal-to-noise ratio (SNR) of 26.5 dB, discriminating metal from air and thus demonstrating its potential for improving PBF part design, process optimization, and defect detection.

Near-field metasurface sensor for an early-stage breast cancer detection

In this paper, a novel and highly sensitive metasurface sensor for microwave breast tumor detection is proposed. The proposed sensor array comprises 8 × 8 small-size sensor elements that are capable of reacting to changes in both electric and magnetic fields. This allows the sensor to detect even minor variations in the surrounding medium, resulting in improved sensitivity. Additionally, designing a sensor array improves sensitivity by covering all areas of the breast tissues with multiple small sensor elements. Numerical studies have been conducted to assess the sensor sensitivity using realistic healthy and non-healthy breast models with diagnosed tumors placed at different locations within healthy breast models in the CST simulation environment at varying stand-off distances. An experiment was conducted to validate the sensor’s concept. It involved testing a metasurface sensor with phantoms resembling both healthy female breast tissues and those with a 10 mm tumor. The results from simulations and experiments demonstrate that the metasurface sensor is capable of detecting breast tumors at different distances. For safety compliance, specific absorption rate (SAR) values were obtained through both simulation and experimentation. The simulated SAR values were calculated to be 0.357 W/kg and 0.216 W/kg at 1 g and 10 g, respectively, using 17 dBm for safety. The measured SAR values were 0.101 W/kg and 0.1 W/kg at 1 g and 10 g, respectively.

СУЧАСНІ ТЕНДЕНЦІЇ У КОНСТРУЮВАННІ ЧУТЛИВИХ ШАРІВ ДЛЯ ОПТИЧНИХ СЕНСОРІВ ТОКСИЧНИХ РЕЧОВИН

The main trends in the creation of sensitive elements of gas sensors for the detection of toxic substances in polluted areas, in industrial premises and the atmosphere are analyzed. An important aspect of the application of gas sensors is the monitoring of the quality of food products, especially of animal origin, since the consumption of spoiled products can be a great danger to human health. The principles of operation and new directions in the field of gas sensor technologies based on thin films of polymers and their nanostructures and composites with semiconductor materials of various types are outlined. Modern trends in the creation of detectors of harmful substances involve the use of new sensor media based on nanostructured components of various nature and the formation of thin film structures, using new, advanced nanotechnological approaches. It is promising to use new compositions of indicator substances (copolymers and layered structures based on poly-3,4-ethylenedioxythiophene, polyanisidine, pentacene, carbon and silicon nanoclusters), and new technological methods of their formation ("in situ" polymerization, layered assembly, electropolymerization and etc.), which do not require the use of complex, expensive equipment. The principles of construction of multifunctional gas sensors are presented. The construction of a gas sensor is proposed, the information signal of which is determined by the selective absorption of the optical medium interacting with the gas. To obtain spectral characteristics, optocouples are used, which consist of controlled sources of optical radiation and photosensitive elements. The key issue for the successful implementation of all improvements in gas sensors and nanosensors at the current stage will remain the search for substances and structures that are highly sensitive to the action of toxic gases, including components of explosive and poisonous substances, and can selectively react to their presence by changing optical and/or electrical properties.

Spiral Annealing of Magnetic Microwires.

A preprocessing technique named "spiral annealing" was applied for the first time to magnetic microwires. In this process, the sample was arranged in a flat spiral shape during annealing, and subsequent measurements were conducted on the unbent sample with the induced stress distribution along and transverse to the sample. The research utilized both magnetic and magneto-optical methods. The anisotropy field magnitude in both the volume and surface of the microwire was measured, and for the first time, a direct correlation between the anisotropy field and the curvature of a spirally annealed microwire was established. Additionally, a connection between the type of surface domain structure and the degree of spiral curvature was identified. The preservation of the distribution of spiral annealing-induced magnetic properties both along and across the microwire is a key effect influencing the technological application of the microwire. The range of induced curvature within which a specific helical magnetic structure can exist was also determined. This insight links the conditions of spiral annealing to the selection of microwires as active elements in magnetic sensors.

Size-tunable transmembrane nanopores assembled from decomposable molecular templates

Transmembrane nanopores, as key elements in molecular transport and single-molecule sensors, are assembled naturally from multiple monomers in the presence of lipid bilayers. The nanopore size, especially the precise diameter of the inner space, determines its sensing targets and further biological application. In this paper, we introduce a template molecule-aided assembly strategy for constructing size-tunable transmembrane nanopores. Inspired by the barrel-like structure, similar to many transmembrane proteins, cyclodextrin molecules of different sizes are utilized as templates and modulators to assemble the α-helical barreled peptide of polysaccharide transporters (Wza). The functional nanopores assembled by this strategy possess high biological and chemical activity and can be inserted into lipid bilayers, forming stable single channels for single-molecule sensing. After enzyme digestion, the cyclodextrins on protein nanopores can be degraded, and the remaining nontemplate transmembrane protein nanopores can also preserve the integrity of their structure and function. The template molecule-aided assembly strategy employed a simple and convenient method for fully artificially synthesizing transmembrane protein nanopores; the pore size is completely dependent on the size of the template molecule and controllable, ranging from 1.1 to 1.8 nm. Furthermore, by chemically synthesized peptides and modifications, the pore function is easily modulated and does not involve the cumbersome genetic mutations of other biological techniques.

Multicolorimetric Sensor Array Based on Silver Metallization of Gold Nanorods for Discriminating Dopaminergic Agents.

Dopaminergic agents are compounds that modulate dopamine-related activity in the brain and peripheral nerves within the pathways on both sides of the blood-brain barrier. Atypical levels of them can precipitate a multitude of neurological disorders, whose timely diagnosis signifies not only stopping the advancement of the illness but also surmounting it. A silver metallized gold nanorod (AuNRs) conditional sensor array, designed to detect dopaminergic agents for assessing nervous system disorders, yielded significant results in simultaneous detection and discrimination of Benserazide (Benz), Levodopa (L-DOPA), and Carbidopa (Carb). The array was composed of two different concentrations of silver ions as sensor elements (SEs), which generated unique signatures indicative of the presence of reductive target analytes, triggered by the incongruent formation of the Au@Ag core-shell, causing visual and fingerprint colorimetric patterns. Generating diverse responses is the key to the functionality of array-based sensing, which facilitated achieving spectral and color variation originating from the blue shift of AuNRs longitudinal localized surface plasmon resonance (LLSPR) in the extinction spectrum. Also, employing a smartphone camera enables clear visual discrimination across an extensive concentration span. Pattern recognition through linear discriminant analysis (LDA) underscored the robust discrimination accuracies of this sensor, along with quantification by means of partial least-squares regression (PLSR), affirming its potential for practical applications. Notably, the array demonstrated high sensitivity in detecting varied concentrations of target analytes, even in commercial drug samples. The sensor responses exhibited a linear correlation with the concentrations of Benz, L-DOPA, and Carb ranging from 1.59 to 100.0, 5.26 to 100.0, and 5.32 to 100.0 μmol L-1, respectively, and the minimum detectable concentrations for Benz, L-DOPA, and Carb were measured at 0.53, 1.75, and 1.77 μmol L-1, respectively. The implemented machine-learning-empowered array-based sensor represents advancements in dopaminergic agent tracing and naked eye detection.

Synthesis and characterisation of carbon nanofiber-wrapped polyaniline and polypyrrole sensory films in polyester resin for strain sensing

ABSTRACT Nanomaterials hold promise as flexible sensor elements due to their enhanced flexibility and efficiency compared to conventional sensors. This study explores Carbon Nanofibers (CNF) in strain-sensing applications, synthesised with Polyaniline (PANI) and Polypyrrole (PPy) via a chemical oxidative technique. These composites form sensory layers on flexible Polyester resin substrates using a layer-by-layer technique. Characterisation through Fourier-Transform Infrared (FTIR) Spectroscopy and Powder X-ray Diffraction (PXRD) reveals strong interactions within CNF/PANI/Polyester and CNF/PPy/Polyester configurations, with heightened crystallinity in CNF/PANI, indicating enhanced electrical conductivity. Stress-strain analysis shows a significant 25% elongation with a corresponding 15% change in resistance across all samples. Calculated gauge factors exhibit substantial improvements: Polyester/PPy (12.96), Polyester/PANI (13.54), Polyester/CNF wrapped PPy (58.62), and Polyester/CNF wrapped PANI (95.8). Notably, CNF-wrapped PPy and CNF-wrapped PANI demonstrate superior gauge factors compared to conventional strain sensors, with Polyester/CNF-wrapped PANI displaying the highest sensitivity at 95.8%. This research underscores the potential of CNF-based composites, particularly CNF-wrapped PANI within a Polyester matrix, for advanced strain-sensing applications.

(Invited) Nanohybrid Carbon Nanotube and P3HT Composite Semiconductor Materials for Solution Processed Optoelectronics

Carbon nanotube networks have demonstrated promise for enabling printable transistors which can be utilized as switching elements within active matrices. Such active matrices have been utilized for controlling pixels and interrogating sensor elements. A new promising technology for imaging, called an active pixel matrix, aims to integrate both the underlying transistor and sensor element within a single device, namely a phototransistor. Carbon nanotubes are poised to enable printable active pixel matrices for sensing applications, however, due to minimal absorption a secondary material needs to be added as a photo synthesizer. Additionally, the material must be sufficiently electrically coupled with the carbon nanotube network to allow for efficient carrier extraction. Our lab has previously developed techniques for crystallizing P3HT directly onto carbon nanotubes using solution-phase soft epitaxy. In this work, the solution phased technique has been adapted to functional carbon nanotube networks already deposited onto a surface.I will present the performance of a device that consists of a solution-processed carbon nanotube network, which acts as the carrier extraction layer, and a surface crystalized P3HT, which acts as the absorption element. First, I will detail the fabrication scheme and soft-epitaxial method of polymer crystallization. Next, I will overview how the P3HT crystallization affects the electronic performance of the devices, including the photo response. The device exhibits high responsivity, with a maximum responsivity value of 3 x 105. Additionally, the device exhibits a wide spectral response within the visible range, due to the exciton generation at the P3HT/CNT interface. I will also present the transient response of the device, which provides insight into the role of carrier injection/trapped states within the material.Lastly, I will discuss the potential applications for an active matrix of phototransistors, including neuromorphic computing. In these specific applications, the semiconductor can be utilized as the functional material within an Organic Electrochemical Transistor (OECT), where it exhibits behavior associated with mixed ionic/electronic conduction (MEIC). I will benchmark the performance, and discuss various methods to fabricated charge trapped switches, a key memory/computational element for future neuromorphic architectures.

Edible and Biodegradable Wearable Capacitive Pressure Sensors: A Paradigm Shift toward Sustainable Electronics with Bio‐Based Materials

AbstractThis study presents a significant advancement in sustainable electronics, introducing an innovative capacitive‐type wearable pressure sensor crafted entirely from edible and biodegradable biomaterials. The sensor's constituents, encompassing the substrate, electrode, and dielectric elements, are obtained using edible and renewable sources, specifically cellulose and pectin. Leveraging their non‐metallic properties, these materials facilitate natural biodegradation, effectively reducing the environmental impact of electronic waste. Employing green chemistry principles during material preparation ensures the exclusion of critical raw materials. The resulting sensors showcase a versatile pressure detection range, from subtle pressures of 100 Pa to a maximum threshold of 100 kPa. Demonstrating a sensitivity of 0.0294 kPa−1in the subtle pressure regime, the sensors exhibit a low detection limit of 10 Pa and a fast response time of 118 ms. The sensors exhibited notable repeatability and robustness, enduring over 10 000 loading‐unloading cycles without succumbing to fatigue. Applied in real‐time human motion detection, the sensors prove their potential applicability. In a biodegradability assessment, all sensor elements exhibit rapid degradation by various fungi, marking a significant stride toward a high‐performance, edible, and wearable capacitive pressure sensor that can be deposited as biowaste at the end of its lifecycle.

Enhanced electrical properties and Vickers hardness of calcium bismuth niobate ceramics by W/Co substituted at B-site

Calcium bismuth niobate (CBN) ceramic, as a core element of high-temperature piezoelectric sensors, has attracted widespread attention due to its high Curie temperature within the class of Aurivillius compounds. However, CBN usually faces two shortcomings: poor piezoelectric constant and low resistivity. In this work, CBN-based ceramics with donor–acceptor ions (W/Co) co-substituted at B-site were prepared by solid-state reaction method, and structure–property relationship of ceramics was studied in detail. Co-substitution of W/Co ions effectively improved the electrical property and hardness of CBN ceramics. CaBi2Nb[Formula: see text](W[Formula: see text]Co[Formula: see text]O9 exhibits enhanced electrical and mechanical properties including high resistivity of [Formula: see text]cm at 500°C, piezoelectric constant of [Formula: see text] pC/N and hardness value of [Formula: see text][Formula: see text]GPa. These values are two orders of magnitude, over two times, and 1.36 times higher than those of pure CBN ceramic, respectively. This work provides a reference for exploring other bismuth-layered structural ceramics.

A novel framework of building operation algorithm for the block of technical diagnostics of aircraft’s automatic control system

This article presents the problem of designing an automatic control system that is stable against errors and failures of sensors on aircraft. The sensor system has a technical diagnostic block that ensures diagnosis and eliminates typical errors and failures. Based on the determination of the error vector, damage can occur by adding measurement elements corresponding to the measurement parameters to the control system. When there are errors or failures of the sensor elements, the state vector of the system changes and is determined by measurements. The difference between the measured vector components when there are errors, failures and when working normally is the basis of the working algorithm of the failure diagnosis block. The results demonstrate encouraging prospects for practical implementations.

Synthesis of nickel-containing metal-polymer nanocomposites and their use as a humidity sensor

In recent years, the synthesis of new gas-sensitive materials for resistive humidity sensors has attracted significant interest. In the present paper, nickel-containing metal-polymer nanocomposites were obtained by thermolysis of nickel itaconate (I) and its complexes with 2,2′-dipyridyl (II), 1,10-phenanthroline (III) and 4′-phenyl-2,2′:6′,2''-terpyridine (IV). The formed nanocomposites were characterized by FTIR, elemental analysis, EDX, SEM, TEM and XRD studies. The most common particle sizes are 28, 12.8, 10.7 and 12.3 nm for the thermolysis products of compounds I–IV respectively. The manufactured sensor samples have good sensitivity to air relative humidity (RH) of 3.24 %/%RH, 4.72 %/%RH, 2.18 %/%RH and 4.37 %/%RH for thermolysis products of compounds I–IV with the polymer binder polyacrylamide, respectively. The average initial resistance of the sensors is 4.54, 15.33, 20.8 and 35.75 MΩ, respectively. Due to the high porosity and moisture absorption of the film, the maximum sensitivity was about 0.003 MΩ/%RH, which indicates a fairly effective behavior of the film with respect to humidity. The response times were 27, 25, 33, 30 s, and the recovery time 47, 44, 51, 49 s, respectively, and repeating the experiment resulted in 87–92 % reproducible results. The fabricated sensors have great potential for use as a humidity sensing element in sensors that can be used for humidity monitoring.

Low gain avalanche diodes for photon science applications

Low Gain Avalanche Diodes (LGADs) are silicon sensors designed to achieve an internal gain in the order of 10 through the impact ionization process. The development of LGADs was pushed forward by their application in High Energy Physics (HEP) experiments, where they will be employed to provide measurements of the time of arrival of minimum ionizing particles with a resolution of around 30 ps. The initial technological implementation of the sensors constrains their minimum channel size to be larger than 1 mm2, in order to reduce inefficiencies due to the segmentation of the gain structure. The gain of the sensors is kept in the order of 10 to limit the sensor shot noise and their power consumption. In photon science, the gain provided by the sensor can boost the signal-to-noise ratio of the detector system, effectively reducing the x-ray energy threshold of photon counting detectors and the minimum x-ray energy where single photon resolution is achieved in charge integrating detectors. This can improve the hybrid pixel and strip detectors for soft and tender x-rays by simply changing the sensor element of the detector system. Photon science applications in the soft and tender energy range require improvements over the LGADs developed for HEP, in particular the presence of a thin entrance window to provide a satisfactory quantum efficiency and channel size with a pitch of less than 100 μm. In this review, the fundamental aspects of the LGAD technology are presented, discussing also the ongoing and future developments that are of interest for photon science applications.