Sensitive Imaging Research Articles

Dense Perovskite Thick Film Enabled by Saturated Solution Filling for Sensitive X-ray Detection and Imaging.

Thick polycrystalline perovskite films synthesized by using solution processes show great potential in X-ray detection applications. However, due to the evaporation of the solvent, many pinholes and defects appear in the thick films, which deteriorate their optoelectronic properties and diminish their X-ray detection performance. Therefore, the preparation of large area and dense perovskite thick films is desired. Herein, we propose an effective strategy of filling the pores with a saturated precursor solution. By adding the saturated perovskite solution to the polycrystalline perovskite thick film, the original perovskite film will not be destroyed because of the solution-solute equilibrium relationship. Instead, it promotes in situ crystal growth within the thick film during the annealing process. The loosely packed grains in the original thick perovskite film are connected, and the pores and defects are partially filled and fixed. Finally, a much denser perovskite thick film with improved optoelectronic properties has been obtained. The optimized thick film exhibits an X-ray sensitivity of 1616.01 μC Gyair-1 cm-2 under an electric field of 44.44 V mm-1 and a low detection limit of 28.64 nGyair s-1 under an electric field of 22.22 V mm-1. These values exceed the 323.86 μC Gyair-1 cm-2 and 40.52 nGyair s-1 of the pristine perovskite thick film measured under the same conditions. The optimized thick film also shows promising working stability and X-ray imaging capability.

Comparative evaluation of imaging methods for prognosis assessment in esophageal squamous cell carcinoma: focus on diffusion-weighted magnetic resonance imaging, computed tomography and esophagography.

To identify the most sensitive imaging examination method to evaluate the prognosis of esophageal squamous cell carcinoma (ESCC). Thirty patients with esophageal squamous cell carcinoma (ESCC) participated in the study and underwent chemoradiotherapy (CRT). They were divided into two groups based on their survival status: the survival group and non-survival group. The diagnostic tests were utilized to determine the most effective imaging examination method for assessing the prognosis. 1. There were no significant differences in tumor length shown on esophagography or computed tomography (CT) or the maximal esophageal wall thickness shown on CT at the specified time points between the two groups. 2. The tumor length on diffusion-weighted imaging (DWI) in the survival group was significantly lower than in the non-survival group at the end of the sixth week of treatment (P=0.001). The area under the ROC curve was 0.840 (P=0.002), and the diagnostic efficiency was moderately accurate. 3. The apparent diffusion coefficient (ADC) values of the survival group were significantly higher than those in the non-survival group at the end of the fourth week and sixth week of treatment (both P<0.001). Areas under the curve were 0.866 and 0.970, with P values of 0.001 and <0.001 and good diagnostic accuracy. Cox regression analyses indicated the ADC at the end of the sixth week of treatment was an independent risk factor. Compared with esophagography and CT, DW-MRI has certain advantages in predicting the prognosis of ESCC.

Value of PET/CT Scanning in Detection of Osseous and Marrow Metastatic Lesions in Cancer Patients

Abstract Background Early diagnosis of cancer remains to be of paramount importance to maximize a patient’s long-term survival and reduce various neurological, hematological, and orthopedic complications that may arise. Skeletal metastasis (SM) is a frequently encountered and important complication of cancer which can lead to intolerable pain. Objectives The goal of the study was to illustrate the value of combined 18F-FDG PET/CT over isolated CT for detection of osseous metastases in cancer patients. Patients and Methods The study included 75 patients. 18F-PET/CT scans were performed. In this study, a lesion-based analysis was performed in detailed retrograde manner. Statistical analysis including specificity, Sensitivity, negative predictive value (NPV) and positive predictive value (PPV) of each of these modalities were calculated. A final diagnosis of metastasis was confirmed by biopsy. Results Combined PET-CT examination is highly sensitive imaging modality in detection of early bone marrow metastatic lesions which are not yet evident on conventional CT study. Conclusion Combined 18-F FDG PET/CT significantly improves the sensitivity and specificity of isolated CT for the detection of osseous and bone marrow metastases. Thus, it adds a significant value that can detect lesions and consequently start a treatment course and improve the overall outcome of the disease process.

Construction of a Spatial-Confined Self-Stacking Catalytic Circuit for Rapid and Sensitive Imaging of Piwi-Interacting RNA in Living Cells.

Piwi-interacting RNAs (piRNAs) are small noncoding RNAs that repress transposable elements to maintain genome integrity. The canonical catalytic hairpin assembly (CHA) circuit relies on random collisions of free-diffused reactant probes, which substantially slow down reaction efficiency and kinetics. Herein, we demonstrate the construction of a spatial-confined self-stacking catalytic circuit for rapid and sensitive imaging of piRNA in living cells based on intramolecular and intermolecular hybridization-accelerated CHA. We rationally design a 3WJ probe that not only accelerates the reaction kinetics by increasing the local concentration of reactant probes but also eliminates background signal leakage caused by cross-entanglement of preassembled probes. This strategy achieves high sensitivity and good specificity with shortened assay time. It can quantify intracellular piRNA expression at a single-cell level, discriminate piRNA expression in tissues of breast cancer patients and healthy persons, and in situ image piRNA in living cells, offering a new approach for early diagnosis and postoperative monitoring.

Role of Multi-Detector Computed Tomography (MDCT) in Assessment of Biliary Neoplasms

Abstract Background Biliary neoplasms are commonly encountered in the day-to-day radiological practice and can be benign or malignant. Multidetector CT (MDCT) is a noninvasive imaging modality for evaluation of patients with biliary obstruction, to localize the cause of obstruction, detect the presence of mass lesion, and define its extension and identify remote metastasis. Objective To find out the role of MDCT scan in the evaluation of biliary neoplasms with respect to nature, cause and level of obstruction. Methods During the period from January 2022 to August 2022, the present study included 30 patients with clinically suspected biliary obstruction and previously radiological or laboratory diagnosed cases of biliary malignancy after fulfilling the inclusion and exclusion criteria and taking written /verbal informed consent. 16 patients were males and 14 were females, their ages ranged between 36– 85 years with mean age of 64years old. Results The mean age of participants was 63.73±11.11 years old; and slight male predominance (53.3%). in correlation to histopathological findings, MDCT was 95.2% sensitive in detection of cholangiocarcinoma (20/21*100). It was 100% sensitive in detection of combined cholangiocarcinoma &amp; HCC (1/1*100). Also it was 85.75 sensitive in detection of gall bladder carcinoma (6/7*100). While it was false positive in detection a case of HCC. The sensitivity of MDCT to detect biliary neoplasm is 96.4% (27/28*100) with specificity of 0% (0/2*100), the positive predictive value is 93.1% (27/29*100) while the negative predictive value is 0% (0/1%). We found significant association between MDCT Final outcome with resectability (P-value 0.002) and between resectability and TNM Staging (P-value &amp;lt;0.0001) Conclusion Multidetector computed tomography MDCT can be considered a noninvasive fast with high sensitivity imaging tool in the assessment of patients with biliary neoplasms. The MDCT is satisfactory for staging of biliary neoplasms and for accurate preoperative assessment of the tumor extent.

Tenfold Increase: Acute Pediatric Mastoiditis Before, During, and After COVID-19 Restrictions.

Acute mastoiditis (AM) is a relatively rare complication arising from acute otitis media, a common condition among children. The COVID-19 pandemic has significantly impacted AM cases. We noted a surge in pediatric AM cases in Germany after COVID-19 restrictions were lifted in 2022. This study assesses AM incidence and the clinical course in children before, during, and after the pandemic. The study also explores complication rates and microbial changes. Participants: We included children (0-18 yr) diagnosed with AM who underwent mastoidectomy at a tertiary-care university hospital from January 2012 to June 2023.Objectives: We aimed to evaluate AM incidence during pre-COVID, COVID, and post-COVID periods; assess complications; and analyze the microbial spectrum.Data Analysis: Incidence and complication rates were compared between periods, along with the microbial spectrum. Population: 75 children were included (median age, 3.3 yr).Incidence: Significant increases in AM cases occurred in the post-COVID period compared to pre-COVID and COVID periods. No significant difference was observed between pre-COVID and COVID periods.Complications: Complication rates increased notably in the post-COVID period compared to pre-COVID and COVID periods with respect to more sensitive imaging methods being used in the post-COVID period. No significant difference was observed between pre-COVID and COVID periods.Spectrum of Pathogens: No significant differences were found in pathogen distribution between periods. Streptococcus pyogenes and Streptococcus pneumoniae were common throughout. The study highlights a substantial rise in AM cases and complications after COVID-19 restrictions were lifted in Germany. This underscores the importance of monitoring infectious diseases and their complications during health crises. Additionally, the study highlights the importance of contrast-enhanced imaging. Further research is needed to explore the mechanisms behind this trend. The study reveals a significant increase in pediatric AM cases and complications following the COVID-19 pandemic in Germany. Adequate computed tomographic or magnetic resonance imaging, including contrast enhancement, is shown to be a very important parameter beside clinical symptoms in deciding for the right therapy. Thus, surgical treatment became more important. Continuous monitoring and adaptive healthcare strategies during health crises are vital for optimal patient care. Further research is warranted to understand the reasons behind these trends and to inform future pandemic preparedness efforts.

Characterizing the consistency of motion of spermatozoa through nanoscale motion tracing

To demonstrate nanoscale motion tracing of spermatozoa and present analysis of the motion traces to characterize the consistency of motion of spermatozoa as a complement to progressive motility analysis. Anonymized sperm samples were videographed under a quantitative phase microscope, followed by generating and analyzing superresolution motion traces of individual spermatozoa. Not applicable. Centrifuged human sperm samples. Not applicable. Precision of motion trace of individual sperms, presence of a helical pattern in the motion trace, mean and standard deviations of helical periods and radii of sperm motion traces, speed of progression. Spatially sensitive quantitative phase imaging with a superresolution computational technique MUltiple SIgnal Classification ALgorithm allowed achieving motion precision of 340 nm using ×10, 0.25 numerical aperture lens whereas the diffraction-limited resolution at this setting was 1,320 nm. The motion traces thus derived facilitated new kinematic features of sperm, namely the statistics of helix period and radii per sperm. Through the analysis, 47 sperms with a speed >25 μm/s were randomly selected from the same healthy donor semen sample, it is seen that the kinematic features did not correlate with the speed of the sperms. In addition, it is noted that spermatozoa may experience changes in the periodicity and radius of the helical path over time. Further, some very fast sperms (e.g., >70 μm/s) may demonstrate irregular motion and need further investigation. Presented computational analysis can be used directly for sperm samples from both fertility patients with normal and abnormal sperm cell conditions. We note that MUltiple SIgnal Classification ALgorithm is an image analysis technique that may vaguely fall under the machine learning category, but the conventional metrics for reporting found in Enhancing the QUAlity and Transparency Of health Research network do not apply. Alternative suitable metrics are reported, and bias is avoided through random selection of regions for analysis. Detailed methods are included for reproducibility. Kinematic features derived from nanoscale motion traces of spermatozoa contain information complementary to the speed of the sperms, allowing further distinction among the progressively motile sperms. Some highly progressive spermatozoa may have irregular motion patterns, and whether irregularity of motion indicates poor quality regarding artificial insemination needs further investigation. The presented technique can be generalized for sperm analysis for a variety of fertility conditions.

High-Fidelity Detection of Large-Scale Atom Arrays in an Optical Lattice.

Recent advances in quantum simulation based on neutral atoms have largely benefited from high-resolution, single-atom sensitive imaging techniques. A variety of approaches have been developed to achieve such local detection of atoms in optical lattices or optical tweezers. For alkaline-earth and alkaline-earth-like atoms, the presence of narrow optical transitions opens up the possibility of performing novel types of Sisyphus cooling, where the cooling mechanism originates from the capability to spatially resolve the differential optical level shifts in the trap potential. Up to now, it has been an open question whether high-fidelity imaging could be achieved in a "repulsive Sisyphus" configuration, where the trap depth of the ground state exceeds that of the excited state involved in cooling. Here, we demonstrate high-fidelity (99.971(1)%) and high-survival (99.80(5)%) imaging of strontium atoms using repulsive Sisyphus cooling. We use an optical lattice as a pinning potential for atoms in a large-scale tweezer array with up to 399 tweezers and show repeated, high-fidelity lattice-tweezer-lattice transfers. We furthermore demonstrate loading the lattice with approximately 10 000 atoms directly from the MOT and scalable imaging over >10 000 lattice sites with a combined survival probability and classification fidelity better than 99.2%. Our lattice thus serves as a locally addressable and sortable reservoir for continuous refilling of optical tweezer arrays in the future.

Millimeter-Wave Band Electro-Optical Imaging System Using Polarization CMOS Image Sensor and Amplified Optical Local Oscillator Source.

In this study, we developed and demonstrated a millimeter-wave electric field imaging system using an electro-optic crystal and a highly sensitive polarization measurement technique using a polarization image sensor, which was fabricated using a 0.35-µm standard CMOS process. The polarization image sensor was equipped with differential amplifiers that amplified the difference between the 0° and 90° pixels. With the amplifier, the signal-to-noise ratio at low incident light levels was improved. Also, an optical modulator and a semiconductor optical amplifier were used to generate an optical local oscillator (LO) signal with a high modulation accuracy and sufficient optical intensity. By combining the amplified LO signal and a highly sensitive polarization imaging system, we successfully performed millimeter-wave electric field imaging with a spatial resolution of 30×60 µm at a rate of 1 FPS, corresponding to 2400 pixels/s.

New breast cancer biomarkers from diffusion magnetic resonance imaging based on the Diffusion Tensor using multivariate curve resolution (MCR) models

Currently, magnetic resonance imaging is the most sensitive imaging technique for detecting cancerous processes in early stages. As for breast cancer, due to the tubular structure of the tissue, being formed by ducts, anisotropic diffusion should be considered instead of the general isotropic diffusion. Anisotropic diffusion is studied by applying a technique called Diffusion Tensor Imaging (DTI), where the diffusion gradient is applied by changing the magnetic field in several spatial directions.To date, the application of Multivariate Curve Resolution (MCR) models in diffusion sequences has demonstrated its ability to develop cancer biomarkers of easy clinical interpretation in the case of isotropic tissues, such as the prostate. But so far, it has never been applied in the case of anisotropic tissues, as the breast.Therefore, the main objective of this work is to obtain easy-to-interpret imaging biomarkers useful for early breast cancer diagnosis from diffusion magnetic resonance imaging based on the Diffusion Tensor using multivariate curve resolution (MCR) models. A classification model to identify healthy and tumor affected pixels is also proposed.

Deep JWST/NIRCam imaging of Supernova 1987A

Abstract JWST/NIRCam obtained high angular-resolution (0.05–0.1”), deep near-infrared 1–5 $\mu$m imaging of Supernova (SN) 1987A taken 35 years after the explosion. In the NIRCam images, we identify: 1) faint H2 crescents, which are emissions located between the ejecta and the equatorial ring, 2) a bar, which is a substructure of the ejecta, and 3) the bright 3–5 $\mu$m continuum emission exterior to the equatorial ring. The emission of the remnant in the NIRCam 1–2.3 $\mu$m images is mostly due to line emission, which is mostly emitted in the ejecta and in the hot spots within the equatorial ring. In contrast, the NIRCam 3–5 $\mu$m images are dominated by continuum emission. In the ejecta, the continuum is due to dust, obscuring the centre of the ejecta. In contrast, in the ring and exterior to the ring, synchrotron emission contributes a substantial fraction to the continuum. Dust emission contributes to the continuum at outer spots and diffuse emission exterior to the ring, but little within the ring. This shows that dust cooling and destruction time scales are shorter than the synchrotron cooling time scale, and the time scale of hydrogen recombination in the ring is even longer than the synchrotron cooling time scale. With the advent of high sensitivity and high angular resolution images provided by JWST/NIRCam, our observations of SN 1987A demonstrate that NIRCam opens up a window to study particle-acceleration and shock physics in unprecedented details, probed by near-infrared synchrotron emission, building a precise picture of how a SN evolves.

Microbursts of the UV atmospheric emission in the auroral zone

In this paper we present data on the UV-microburst (300–400 nm flashes with a duration less than 1 s) measurements in the auroral zone. Measurements were performed during the period 09.2021–04.2022 by the highly sensitive imaging photometer installed at the Verkhnetulomsky observatory of the Polar Geophysical Institute. It is shown that microbursts are grouped in a series with a duration from 10 s to 10 min. They were observed in relatively quiet geomagnetic conditions (KP < 3) at the southern boundary of the auroral oval in the evening magnetic local time (MLT) sector. UV-microbursts are observed in different observational conditions (clouds, transparent clouds and clear sky) and spatially represent various patterns: uniform diffuse illumination, local spots. Joint analyses of the optical measurements and satellite data on charged particle fluxes demonstrates that an auroral oval, characterized by a plasma, is placed to the north of the observatory. At the same time increased flux of electrons with energy more than 100 keV is observed at the same L-shell and MLT sector. The possible origin of the UV-microbursts is a precipitation of energetic electrons from a poleward boundary of the outer radiation belt in a form of relativistic electron microbursts is discussed.

Near-infrared AIEgens for sulfatase imaging in breast cancer in vivo.

Aggregation-induced emission luminogens (AIEgens) enable highly sensitive and in situ visualization of sulfatase to benefit the early diagnosis of breast cancer (BC), but current sulfatase AIEgens always emit visible light (<650 nm). Herein, a near-infrared (NIR) AIEgen QMT-SFA is developed for sulfatase imaging in vivo. Hydrophilic QMT-SFA is cleaved by sulfatase to yield hydrophobic QMT-OH, which subsequently aggregates into nanoparticles to turn the AIE fluorescence "on", enabling sensitive sulfatase imaging in 4T1 cells and mouse models.

Confocal Surface-Enhanced Raman Imaging of the Intestinal Barrier Crossing Behavior of Model Nanoplastics in Daphnia Magna.

Nanoplastics (nP) pose hazards to aquatic animals once they are ingested. Significant knowledge gaps exist regarding the nP translocation across the animal intestine, which is the first barrier between the ingested nP and the animal body. We examined the intestinal barrier crossing behavior of nP in an aquatic animal model (Daphnia magna) and determined the translocation mechanism with the help of model "core-shell" polystyrene nanoplastics (nPS) and confocal surface-enhanced Raman spectroscopy (SERS). The Raman reporter (4-mercaptobenzoic acid)-tagged gold "core" of the model nPS enables sensitive and reliable particle imaging by confocal SERS. This method detected SERS signals of model nPS concentration as low as 4.1 × 109 particles/L (equivalent to 0.27 μg/L PS "shell" concentration). The translocation was observed with the help of multilayer stacked Raman maps of SERS signals of the model nPS. With a higher concentration or longer exposure time of the model nPS, uptake and translocation of the plastic particles increased. In addition, we demonstrated that clathrin-dependent endocytosis and macropinocytosis were two major mechanisms underlying the translocation. This study contributes to a mechanistic understanding of nP translocation by using the pioneering model nPS and an analytical toolkit, which undergird further investigations into nP behavior and health effects in aquatic species.

In vitro and in vivo evaluation of biohybrid tissue-engineered vascular grafts with transformative 1H/19F MRI traceable scaffolds

Biohybrid tissue-engineered vascular grafts (TEVGs) promise long-term durability due to their ability to adapt to hosts' needs. However, the latter calls for sensitive non-invasive imaging approaches to longitudinally monitor their functionality, integrity, and positioning. Here, we present an imaging approach comprising the labeling of non-degradable and degradable TEVGs' components for their in vitro and in vivo monitoring by hybrid 1H/19F MRI. TEVGs (inner diameter 1.5 mm) consisted of biodegradable poly(lactic-co-glycolic acid) (PLGA) fibers passively incorporating superparamagnetic iron oxide nanoparticles (SPIONs), non-degradable polyvinylidene fluoride scaffolds labeled with highly fluorinated thermoplastic polyurethane (19F-TPU) fibers, a smooth muscle cells containing fibrin blend, and endothelial cells. 1H/19F MRI of TEVGs in bioreactors, and after subcutaneous and infrarenal implantation in rats, revealed that PLGA degradation could be faithfully monitored by the decreasing SPIONs signal. The 19F signal of 19F-TPU remained constant over weeks. PLGA degradation was compensated by cells’ collagen and α-smooth-muscle-actin deposition. Interestingly, only TEVGs implanted on the abdominal aorta contained elastin. XTT and histology proved that our imaging markers did not influence extracellular matrix deposition and host immune reaction. This concept of non-invasive longitudinal assessment of cardiovascular implants using 1H/19F MRI might be applicable to various biohybrid tissue-engineered implants, facilitating their clinical translation.

Use of PSMA PET/CT to detect prostate cancer metastatic to a preexisting thyroid nodule

Prostate cancer (PCa) seldom metastasizes to the thyroid gland, and only a limited number of cases are documented in the literature. The application of a relatively recent and highly sensitive imaging technique, prostate-specific membrane antigen (PSMA) positron emission tomography—computed tomography (PET/CT), has enhanced the identification of metastatic disease. Nevertheless, as PSMA is expressed in various tissue types, the clinical importance of a PSMA-avid thyroid lesion remains largely uncertain. A minor, yet noteworthy, percentage of these lesions are ultimately determined to be malignant. Here we describe the case of a 70-year-old man with a past medical history of Lynch syndrome who presented to an outpatient oncologic clinic for management of very high risk localized PCa. He developed metastatic recurrence and his disease progressed through several lines of therapy, including immunotherapy and targeted treatments. He was found to have a new, intense PSMA uptake in an existing, previously benign thyroid nodule. Sonographic evaluation revealed changing morphology despite grossly stable size. Repeat biopsy confirmed the unusual finding of PCa metastasis to a known thyroid nodule. The shift in PSMA avidity played a pivotal role in discerning this metastatic deposit. There is a potential risk that such lesions may be inadequately acknowledged. The impact of the patient’s Lynch syndrome on this presentation remains uncertain.

Intrarenal pH-Responsive Self-Assembly of Luminescent Gold Nanoparticles for Diagnosis of Early Kidney Injury.

Metabolic acidosis-induced kidney injury (MAKI) is asymptomatic and lack of clinical biomarkers in early stage, but rapidly progresses to severe renal fibrosis and ultimately results in end-stage kidney failure. Therefore, developing rapid and noninvasive strategies direct responsive to renal tubular acidic microenvironment rather than delayed biomarkers are essential for timely renoprotective interventions. Herein, we develop pH-responsive luminescent gold nanoparticles (p-AuNPs) in the second near-infrared emission co-coated with 2,3-dimethylaleic anhydride conjugated β-mercaptoethylamine and cationic 2-diethylaminoethanethiol hydrochloride, which showed sensitive pH-induced charge reversal and intrarenal self-assembly for highly sensitive and long-time (~24 h) imaging of different stages of MAKI. By integrating advantages of pH-induced intrarenal self-assembly and enhanced interactions between pH-triggered positively charged p-AuNPs and renal tubular cells, the early- and late-stage MAKI could be differentiated rapidly within 10 min post-injection (p.i.) with contrast index (CI) of 3.5 and 4.3, respectively. The corresponding maximum CI could reach 5.1 and 9.2 at 12 h p.i., respectively. Furthermore, p-AuNPs were demonstrated to effectively real-time monitor progressive recovery of kidney injury in MAKI mice after therapy, and also exhibit outstanding capabilities for drug screening. This pH-responsive strategy showed great promise for feedback on kidney dysfunction progression, opening new possibilities for early-stage diagnosis of pH-related diseases.

Magnetic Particle Imaging Reveals that Iron-Labeled Extracellular Vesicles Accumulate in Brains of Mice with Metastases.

The incidence of breast cancer remains high worldwide and is associated with a significant risk of metastasis to the brain that can be fatal; this is due, in part, to the inability of therapeutics to cross the blood-brain barrier (BBB). Extracellular vesicles (EVs) have been found to cross the BBB and further have been used to deliver drugs to tumors. EVs from different cell types appear to have different patterns of accumulation and retention as well as the efficiency of bioactive cargo delivery to recipient cells in the body. Engineering EVs as delivery tools to treat brain metastases, therefore, will require an understanding of the timing of EV accumulation and their localization relative to metastatic sites. Magnetic particle imaging (MPI) is a sensitive and quantitative imaging method that directly detects superparamagnetic iron. Here, we demonstrate MPI as a novel tool to characterize EV biodistribution in metastatic disease after labeling EVs with superparamagnetic iron oxide (SPIO) nanoparticles. Iron-labeled EVs (FeEVs) were collected from iron-labeled parental primary 4T1 tumor cells and brain-seeking 4T1BR5 cells, followed by injection into the mice with orthotopic tumors or brain metastases. MPI quantification revealed that FeEVs were retained for longer in orthotopic mammary carcinomas compared to SPIOs. MPI signal due to iron could only be detected in brains of mice bearing brain metastases after injection of FeEVs, but not SPIOs, or FeEVs when mice did not have brain metastases. These findings indicate the potential use of EVs as a therapeutic delivery tool in primary and metastatic tumors.

Ultranarrow-bandgap small-molecule acceptor enables sensitive SWIR detection and dynamic upconversion imaging.

Short-wavelength infrared (SWIR) light detection plays a key role in modern technologies. Emerging solution-processed organic semiconductors are promising for cost-effective, flexible, and large-area SWIR organic photodiodes (OPDs). However, the spectral responsivity (R) and specific detectivity (D*) of SWIR OPDs are restricted by insufficient exciton dissociation and high noise current. In this work, we synthesized an SWIR small molecule with a spectral coverage of 0.3 to 1.3 micrometers peaking at 1100 nanometers. The photodiode, with optimized exciton dissociation, charge injection, and SWIR transmittance, achieves a record high R of 0.53 ampere per watt and D* of 1.71 × 1013 Jones at 1110 nanometers under zero bias. The D* at 1 to 1.2 micrometers surpasses that of the uncooled commercial InGaAs photodiode. Furthermore, large-area semitransparent all-organic upconversion devices integrating the SWIR photodiode realized static and dynamic SWIR-to-visible imaging, along with excellent upconversion efficiency and spatial resolution. This work provides alternative insights for developing sensitive organic SWIR detection.

Imaging ultra-weak UV light below 100 pW cm-2 using a 4H-SiC photodetector with an Al2O3 interfacial layer.

Weak light detection is crucial in various practical applications such as night vision systems, flame monitoring, and underwater operations. Decreasing the dark current of a photodetector can effectively mitigate noises, consequently enhancing the signal-to-noise ratio and overall weak light detection performance. Herein, we demonstrate a 4H-SiC UV photodetector capable of detecting extremely weak UV light. This device comprises a photosensitive layer of 4H-SiC, two TiN electrodes and an atomically thin Al2O3 interfacial layer between TiN and the C surface of 4H-SiC. Under 360 nm UV light illumination, the proposed Al2O3 device demonstrates an ultra-low dark current of 18 fA, possibly benefiting from the effective passivation of interfacial carriers, and a boosted photo-to-dark current ratio of 6.7 × 107. Consequently, it achieves a weak-light detection limit as low as 31.8 pW cm-2, significantly outperforming the control device lacking Al2O3. When compared to previously reported SiC photodetectors, our Al2O3 device boasts an exceptional large linear dynamic range of 172 dB. Leveraging this, we construct a photodetector array capable of clearly imaging an object under ultra-weak light illumination below the 100 pW cm-2 level. The proposed photodetector represents a significant advancement in the development of highly sensitive image sensors for weak light detection.