Ultrasensitive Detectors Research Articles

An AI-assisted microfluidic paper-based multiplexed surface-enhanced raman scattering (SERS) biosensor with electrophoretic removal and electrical modulation for accurate acute myocardial infarction (AMI) diagnosis and prognosis

SERS detects single molecules with exceptional sensitivity. To counter the issue of selectivity faced by point-of-care, herein, an externally applied electric field that allows electrical modulation and electromigrates unbound SERS tags without multiple washing steps is successfully developed and demonstrated to improve the biosensor's selectivity and sensitivity in multiplexed detection of cTnI, HDL, and LDL in human serum at a low LoD. Ultra-sensitive detectors can detect signals from non-specifically absorbed species, and these species can cover up overlapping analyte peaks, amplifying the effect of non-specific binding. Even though antifouling molecules can prevent non-specific adsorption at the sensor interface, this approach does not completely eliminate it. Our significant findings show that an electrically regulated device can electromigrate non-specifically bound species without cross-reacting with endogenous albumin proteins. Stability, repeatability, and reproducibility were good, with an RSD of 10%. Artificial intelligence was employed to interpret and analyze high-dimensional fingerprint SERS spectra using feature selection and dimensionality reduction for accurate acute myocardial infarction diagnosis and prognosis. These machine learning methods allow quantification of cTnI, HDL, and LDL biomarkers with low RMSE. Machine learning classifiers showed strong AUROC values of 0.950 ± 0.111 and 0.884 ± 0.139 for early and recurrent AMI detection, respectively. A high negative predictive value (NPV) of ≥99% indicates an effective early AMI rule-out. In short, this work demonstrated that a simple, low-cost, electrophoretic modulated biosensor with machine learning can diagnose, rule out, and predict recurring AMI.

Sagnac-witnessed laser deflection is an ultra-sensitive acoustic detector.

Laser-deflection-based acoustic sensing is known for high bandwidth but low sensitivity. By embedding the sensing laser within a Sagnac interferometer and incorporating split-beam detection-originally developed for optical trapping microscopy-we demonstrate sensitive acoustic detection in air with a 2 MHz bandwidth. In a direct comparison, our method far-exceeds performance metrics of a state-of-the-art, commercially-available, high-bandwidth microphone. In upcoming large-volume-bubble-chamber searches for dark matter, our method could replace traditional acoustic sensors confined to the chamber's exterior where signals are weakest.

An Ultrasensitive Molecular Detector for Direct Sensing of Spin Currents at Room Temperature.

The experimental analysis of pure spin currents at interfaces is one major goal in the field of magnonics and spintronics. Complementary to the established Spin-Hall effect using the spin-to-charge conversion in heavy metals for information processing, we present a novel approach based on spin pumping detection by an interfacial, resonantly excited molecular paramagnet adsorbed to the surface of the spin current generating magnet. Here, we show that the sensitivity of this electron paramagnetic resonance (EPR) detector can be enhanced by orders of magnitude through intramolecular transfer of spin polarization at room temperature. Our proof-of-principle sample consists of octahedral-shaped ferrimagnetic Fe3O4 nanoparticles covered by oleic acid (OA) which has two paramagnetic centers, S1 and S2. S1 arises from the chemisorption of OA and is located directly at the interface to Fe3O4. S2 originates from radical formation at the center of the molecule close to the double bond of oleic acid and is not influenced by chemisorption. Using ferromagnetic resonance (FMR) excitation of the Fe3O4 nanoparticles to pump spins into S1, a population inversion of the spin-split levels of S2 is formed, vastly enhancing the detection sensitivity on the atomic scale.

LiAlO2:Gd-Based Versatile and Ultrasensitive Detector for Gamma and Neutrons by Thermal and Optical Stimulation.

Considering the low-level dose detection requirement for neutron and γ radiation in cancer therapy, synthesis and exploratory studies have been performed on a newly developed phosphor LiAlO2:Gd. Our results reveal that the presence of both Li and Gd makes it sensitive to both gamma and thermal neutrons. The applicability of LiAlO2:Gd for beta, gamma, and neutrons in both thermally stimulated and optically stimulated modes has been verified by extensive experiments followed by kinetic parametric evaluation with theoretical calculations. The current work confirms that LiAlO2:Gd is a highly sensitive phosphor with a minimum detectable dose of 5.7 μSv for gamma and 92 μSv for themral neutrons. The phosphor is found to show very high sensitivity at low energy and dose. Its ability for detection and discrimination of both gamma and thermal neutrons makes it a potential material to be used in medical dosimetry.

Transition Edge Sensors with Sub-eV Resolution And Cryogenic Targets (TESSERACT) at the underground laboratory of Modane (LSM)

The future TESSERACT experiment will search for individual galactic DM particles below the proton mass through interactions with advanced, ultra-sensitive detectors. Currently TESSERACT is in a design phase aiming to produce fully defined detector technologies that will explore DM masses down to 10 MeV. It is designed to be sensitive to DM candidates interacting with the detector target material in producing both nuclear recoil DM (NRDM) and electron recoil (ERDM). To do so, multiple target materials will be used with varying detection strategies to ensure the capability to both actively reject the so-called low-energy excess and discriminate nuclear recoils against electron recoils. In addition to maximizing sensitivity to a variety of DM interactions, this provides an independent handle on instrumental backgrounds. Nowadays, the TESSERACT project encompasses two US-based technologies, namely HeRALD using superfluid helium as a target material, and SPICE using polar crystals (Al2O3 and SiO2) and scintillating crystals such as GaAs. In these proceedings, we discuss the recent proposal to host the future TESSERACT experiment at the Modane Underground Laboratory (LSM) and add a third French-based cryogenic semiconducting (Ge, Si) detector technology to the TESSERACT payload.

Ultracoherent Nanomechanical Resonators Based on Density Phononic Crystal Engineering

Micromechanical and nanomechanical systems with exceptionally low dissipation rates are enabling the next-generation technologies of ultrasensitive detectors and quantum information systems. New techniques and methods for lowering the dissipation rate have in recent years been discovered and allowed for the engineering of mechanical oscillators with phononic modes that are extremely well isolated from the environment and thus possess quality factors close to and beyond 1×109. A powerful strategy for isolating and controlling a single phononic mode is based on phononic crystal engineering. Here we propose a new method for phononic crystal engineering of nanomechanical oscillators that is based on a periodic variation of the material density. To circumvent the introduction of additional bending losses resulting from the variation of material density, the added mass constitutes an array of nanopillars in which the losses will be diluted. Using this novel technique for phononic crystal engineering, we design and fabricate corrugated mechanical oscillators with quality factors approaching 1×109 in a room temperature environment. The flexibility space of these new phononic crystals is large and further advancement can be attained through optimized phononic crystal patterning and strain engineering via topology optimization. This will allow for the engineering of mechanical membranes with quality factors beyond 1×109 at room temperature. Such extremely low mechanical dissipation rates will enable the development of radically new technologies such as quantum-limited atomic force microscopy at room temperature, ultrasensitive detectors of dark matter, spontaneous waveform collapses, gravity, and high-efficiency quantum information transducers. Published by the American Physical Society 2024

Integrated chromosomal instability and tumor microbiome redefined prognosis-related subtypes of pancreatic cancer

BackgroundPancreatic cancer is a common malignancy with poor prognosis and limited treatment. Here we aimed to investigate the role of host chromosomal instability (CIN) and tumor microbiome in the prognosis of pancreatic cancer patients. MethodsOne hundred formalin-fixed paraffin-embedded (FFPE) pancreatic cancer samples were collected. DNA extracted from FFPE samples were analyzed by low-coverage whole-genome sequencing (WGS) via a customized bioinformatics workflow named ultrasensitive chromosomal aneuploidy detector. ResultsSamples are tested according to the procedure of ultrasensitive chromosomal aneuploidy detector (UCAD). We excluded 2 samples with failed quality control, 1 patient lost to follow-up and 6 dead in the perioperative period. The final 91 patients were admitted for the following analyses. Thirteen (14.3%) patients with higher CIN score had worse overall survival (OS) than those with lower CIN score. The top 20 microbes in pancreatic cancer samples included 15 species of bacteria and 5 species of viruses. Patients with high human herpesvirus (HHV)-7 and HHV-5 DNA reads exhibited worse OS. Furthermore, we classified 91 patients into 3 subtypes. Patients with higher CIN score (n =13) had the worst prognosis (median OS 6.9 mon); patients with lower CIN score but with HHV-7/5 DNA load (n = 24) had worse prognosis (median OS 10.6 mon); while patients with lower CIN score and HHV-7/5 DNA negative (n = 54) had the best prognosis (median OS 21.1 mon). ConclusionsHigh CIN and HHV-7/5 DNA load were associated with worse survival of pancreatic cancer. The novel molecular subtypes of pancreatic cancer based on CIN and microbiome had prognostic value.

Challenges for dark matter direct search with SiPMs

Liquid xenon and liquid argon detectors are leading the direct dark matter search and are expected to be the candidate technology for the forthcoming generation of ultra-sensitive large-mass detectors. At present, scintillation light detection in those experiments is based on ultra-pure low-noise photo-multipliers. To overcome the issues in terms of the extreme radio-purity, costs, and technological feasibility of the future dark matter experiments, the novel silicon photomultiplier (SiPM)-based photodetector modules seem to be promising candidates, capable of replacing the present light detection technology. However, the intrinsic features of SiPMs may limit the present expectations. In particular, interfering phenomena, especially related to the optical correlated noise, can degrade the energy and pulse shape resolutions. As a consequence, the projected sensitivity of the future detectors has to be reconsidered accordingly.

An ultra-sensitive colloidal quantum dot infrared photodiode exceeding 100 000% external quantum efficiency via photomultiplication.

In this study, we present ultrasensitive infrared photodiodes based on PbS colloidal quantum dots (CQDs) using a double photomultiplication strategy that utilizes the accumulation of both electron and hole carriers. While electron accumulation was induced by ZnO trap states that were created by treatment in a humid atmosphere, hole accumulation was achieved using a long-chain ligand that increased the barrier to hole collection. Interestingly, we obtained the highest responsivity in photo-multiplicative devices with the long ligands, which contradicts the conventional belief that shorter ligands are more effective for optoelectronic devices. Using these two charge accumulation effects, we achieved an ultrasensitive detector with a responsivity above 7.84 × 102 A W-1 and an external quantum efficiency above 105% in the infrared region. We believe that the photomultiplication effect has great potential for surveillance systems, bioimaging, remote sensing, and quantum communication.

EVs‐on‐a‐Bubble: Self‐Aggregated Click Bubbles Streamline Isolation and Amplified Profiling of Circulating Extracellular Vesicles

AbstractTumor‐derived circulating extracellular vesicles (EVs) provide a non‐invasive solution for cancer diagnostics, but hampered by challenges in EVs isolation and profiling. Herein, this work shows that bioorthogonal microbubbles (click bubbles) combine a panel of fluorescent aptamers for streamlined isolation and profiling of oncologic EVs in a single assay. This click bubble‐driven aptasensor (cBAS) features self‐aggregation, self‐separation and self‐enhancing in fluorescence. The facile protein phase transition renders bubble surface polyvalent with rich clickable motifs, enabling fast enrichment of EVs. Moreover, the buoyancy allows click bubbles to self‐float to the droplet apex for self‐aggregated fluorescence enhancement via a bubble lensing effect, thus achieving a sensitive profiling of EVs without requiring additional signal amplification or ultrasensitive detectors. By using cBAS to profile EVs surface proteins from a cohort (n = 45) across three cancer types, a machine learning algorithm enables cancer diagnosis and classification with an overall accuracy of 91%. This EVs‐on‐a‐bubble assay is fast, sensitive, self‐powered, and provides a promising tool to facilitate EVs‐based cancer diagnosis in clinical settings.

Snowmass2021 cosmic frontier white paper: Ultraheavy particle dark matter

We outline the unique opportunities and challenges in the search for “ultraheavy” dark matter candidates with masses between roughly 10 TeV and the Planck scale m_{\rm pl} ≈ 10^{16} TeV. This mass range presents a wide and relatively unexplored dark matter parameter space, with a rich space of possible models and cosmic histories. We emphasize that both current detectors and new, targeted search techniques, via both direct and indirect detection, are poised to contribute to searches for ultraheavy particle dark matter in the coming decade. We highlight the need for new developments in this space, including new analyses of current and imminent direct and indirect experiments targeting ultraheavy dark matter and development of new, ultra-sensitive detector technologies like next-generation liquid noble detectors, neutrino experiments, and specialized quantum sensing techniques.

Ultrasensitive and Robust CsPbBr3 Single-Crystal X-ray Detectors Based on Interface Engineering.

Halide lead perovskites have shown great development in recent years for ionizing radiation detection. However, the bias-induced interfacial electrochemical reaction between the perovskite and electrode severely deteriorates detector performance. We report that BCP strongly interacts with Al and constructs a stable Al-BCP chelating interface, resulting in the suppression of a detrimental electrochemical reaction. The fabricated Au/Al/BCP/C60/CsPbBr3/Au detector shows a low dark current of 3 nA with a stable baseline at an extremely high bias of 100 V (∼100 V mm-1). The superior high-bias stability enables a high sensitivity of 7.3 × 104 μC Gyair-1 cm-2 at 100 V. Meanwhile, a low detection limit of 15 nGyair s-1 at 40 V is achieved due to the reduced noise. The outstanding performance of our device exceeds that of most advanced detectors based on CsPbBr3 single crystals. Besides, X-ray imaging with 1 mm spatial resolution is well demonstrated at a low dose rate of 200 nGyair s-1. The interfacial chelating strategy overcomes the technical limitation of bias-induced instability of perovskite radiation detectors and can be anticipated to operate under an extremely high electrical field.

Ultra-sensitive terahertz introduced harmonic emission towards terahertz detection

The sixth-generation (6G) technology has garnered significant interest from researchers due to its improved spectral and energy efficiency. However, a major challenge lies in the strong attenuation of terahertz waves in the air, necessitating the development of ultra-sensitive detectors. In recent years, there has been gradual progress in the development of harmonic signal detection methods, offering a new solution for terahertz wave detection with a low detection threshold and high sensitivity. In our study, we proposed a highly sensitive detection approach involving a 1040 nm femtosecond laser and broadband terahertz waves incident on SnSe2 nanosheets with a few layers, obtained through mechanical exfoliation. Utilizing confocal microscopy, the distinct harmonic wave can be observed, with the intensity of the harmonic signal varying based on the polarization angle difference between the laser and terahertz waves. Our estimation suggests that this detection sensitivity could be around ten times higher than that of existing detectors. This approach, which involves THz-induced harmonic generation without the need for high voltage or intense THz/laser exposure, holds immense potential for weak signal detection applications and carries significant importance for the advancement of 6G technology.

Recent advances in measurement of metabolic clearance, metabolite profile and reaction phenotyping of low clearance compounds

ABSTRACT Introduction Low metabolic clearance is usually a highly desirable property of drug candidates in order to reduce dose and dosing frequency. However, measurement of low clearance can be challenging in drug discovery. A number of new tools have recently been developed to address the gaps in the measurement of intrinsic clearance, identification of metabolites, and reaction phenotyping of low clearance compounds. Areas covered The new methodologies of low clearance measurements are discussed, including the hepatocyte relay, HepatoPac®, HμREL®, and spheroid systems. In addition, metabolite formation rate determination and in vivo allometric scaling approaches are covered as alternative methods for low clearance measurements. With these new methods, measurement of ~ 20-fold lower limit of intrinsic clearance can be achieved. The advantages and limitations of each approach are highlighted. Expert opinion Although several novel methods have been developed in recent years to address the challenges of low clearance, these assays tend to be time and labor intensive and costly. Future innovations focusing on developing systems with high enzymatic activities, ultra-sensitive universal quantifiable detectors, and artificial intelligence will further enhance our ability to explore the low clearance space.

Sponge-inspired MXene@CeO2 detector for ultra-sensitive detection of glucose

Non-invasive sweat detectors can monitor the glucose level of diabetes in a painless way. However, most detectors need to collect enough sweat through external exercise or active stimulation, which increases the inconvenience of the user and reduces the applicable population. In this study, we propose an ultra-sensitive biomimetic glucose detector to detect the sweat produced by thermoregulation without additional exercise and stimulation. Inspired by the predator process of sponge in the sea, the sensing material of MXene (Ti3C2Tx) @CeO2 hydrogels employed the “laminae-trestle-laminae” (L-T-L) structure of sponge to adsorb and transport glucose molecules in sweat. CeO2 grafted onto the MXene surface can detect glucose by the catalytic activity of CeO2. The glucose detector with an ultra-low limit of detection (LOD = 0.004 μM), excellent sensitivity (801.27 μA⋅μM−1⋅cm−2), and a broad linear detection range (LDR = 0.01–2.5 μM) can satisfy detection requirements in human sweat after dilution. In real applications, the detector can detect glucose in the sweat of diabetic patients for five consecutive days and detect the glucose content in the daily drinks of patients. Our findings demonstrate the high potential of sponge-inspired MXene@CeO2 glucose detector for routine medical testing.

Numerical design of surface magneto-plasmon sensors of Au/Co double-layer square arrayed nanopores on the continuous gold thin film

Surface magneto-plasmon (SMP) sensors have attracted continuous attention due to their field enhanced signal-to-noise ratios, sensitivities, and detection limits. Although many progresses have been achieved in the nanodots, nanorods, or nanodiscs, few studies have been conducted on films containing arrays of nanopores or nanoholes. SMP sensors based on arrays of nanopores could be much more promising for future ultrasensitive optical detectors since they can couple the SMP enhancement with Fabry–Pérot interference of nanopores for high-performance resonator sensors that can be further tuned under a magnetic field. We, thus, propose a high-performance SMP sensor based on the magneto-optical Kerr effect (MOKE) of films containing a square array of Au–Co double-layer nanopores on the Au film substrate or SMP-MOKE sensor. The local electric field around the magneto-plasmon arrays of nanopore photonic crystals can be greatly enhanced by applying an external magnetic field due to their magneto-optical activity and excitation of high-quality surface plasmon resonances. Multi-physics coupling simulations and validation by COMSOL on the structure-dependent optical properties suggest that the proposed SMP-MOKE sensor has a high sensitivity of 711 nm/Refractive Index Units (RIUs) and a figure of merit (FOM) of the order of 105 RIU−1, which is an order of magnitude greater than the best grating-type sensors, to the best of our knowledge. Our results shall facilitate the theoretical design for the future fabrication of ultra-sensitive sensors or resonators with excellent FOM and reliability for air-quality monitoring or chemical sensing, etc.

Ultra-sensitive voltage-controlled skyrmion-based spintronic diode

We have designed a passive spintronic diode based on a single skyrmion stabilized in a magnetic tunnel junction and studied its dynamics induced by voltage-controlled magnetic anisotropy (VCMA) and Dzyaloshinskii–Moriya interaction (VDMI). We have demonstrated that the sensitivity (rectified output voltage over input microwave power) with realistic physical parameters and geometry can be larger than 10 kV W−1 which is one order of magnitude larger than diodes employing a uniform ferromagnetic state. Our numerical and analytical results on the VCMA and VDMI-driven resonant excitation of skyrmions beyond the linear regime reveal a frequency dependence on the amplitude and no efficient parametric resonance. Skyrmions with a smaller radius produced higher sensitivities, demonstrating the efficient scalability of skyrmion-based spintronic diodes. These results pave the way for designing passive ultra-sensitive and energy efficient skyrmion-based microwave detectors.

Observation of Magnetic State Dependent Thermoelectricity in Superconducting Spin Valves.

Superconductor-ferromagnet tunnel junctions demonstrate giant thermoelectric effects that are being exploited to engineer ultrasensitive terahertz radiation detectors. Here, we experimentally observe the recently predicted complete magnetic control over thermoelectric effects in a superconducting spin valve, including the dependence of its sign on the magnetic state of the spin valve. The description of the experimental results is improved by the introduction of an interfacial domain wall in the spin filter layer interfacing the superconductor. Surprisingly, the application of high in-plane magnetic fields induces a double sign inversion of the thermoelectric effect, which exhibits large values even at applied fields twice the superconducting critical field.

Advanced functional rGO@MoS2@PEDOT: PSS multicomponent-based nanocomposite films for rapid and ultra-sensitive TNT detection

Ultra-sensitive and highly selective detectors are attracting increasing attention to combat any undesired terrorist activities. High sensitivity and selectivity are the two major concerns for the development of the sensor for explosive detection. Herein, 2,4,6 TNT explosive sensor based on multicomponent nanocomposite film (Mc-NFs) is fabricated through an interface modulation technique. The Mc-NFs, porphyrin functionalized rGO@MoS2 @PEDOT: PSS (TPP-rGO@MoS2 @PEDOT: PSS) films, exhibit excellent selectivity and ultra-sensitivity towards TNT vapor at room temperature with outstanding sensing response (246% for 1.5 ppb), a rapid response time (3.5 s). The obtained results reveal the synergistic actions of the individual sensor components, where the rich active sites of MoS2 are playing a major role in high sensing response, π-π interactions between TPP-rGO and TNT lead to rapid adsorption/desorption of TNT vapors, and PEDOT: PSS assures the homogenous dispersion of the components in the sensor film. Further, the film exhibits excellent selectivity towards highly oxidizing TNT vapors due to strong N-type nature of the film along with the functionalization of rGO with porphyrin. The sensor has also been investigated for different concentrations of TNT vapors in the concentration range of 1.5–47ppb, showing an average rapid response time of 2 s, and recovery time of 42.5 s. The sensor has a high sensitivity of 4.09% /ppb, remarkable linearity (R-value > 0.976), good reproducibility and repeatability, low limit of detection (0.1 ppb), and good sensing stability. The prepared TPP-rGO-10%@MoS2-5%@PEDOT: PSS film has the potential to be used as an ultra-sensitive TNT detector in handheld devices.

Cryogenic sensor enabling broad-band and traceable power measurements

Recently, great progress has been made in the field of ultrasensitive microwave detectors, reaching even the threshold for utilization in circuit quantum electrodynamics. However, cryogenic sensors lack the compatibility with broad-band metrologically traceable power absorption measurements at ultralow powers, which restricts their range of applications. Here, we demonstrate such measurements using an ultralow-noise nanobolometer, which we extend by an additional direct-current (dc) heater input. The tracing of the absorbed power relies on comparing the response of the bolometer between radio frequency and dc-heating powers traced to the Josephson voltage and quantum Hall resistance. To illustrate this technique, we demonstrate two different methods of dc-substitution to calibrate the power that is delivered to the base temperature stage of a dilution refrigerator using our in situ power sensor. As an example, we demonstrate the ability to accurately measure the attenuation of a coaxial input line between the frequencies of 50MHz and 7GHz with an uncertainty down to 0.1 dB at a typical input power of -114 dBm.