A long-standing challenge in nanozyme catalysis is low activity at physiological pH, especially for oxidase- and peroxidase-mimicking nanozymes. We herein communicate that Mn(II) can promote ...catalysis at neutral pH for carbon dots (C-dots) as a photo-oxidase nanozyme. The C-dots produce singlet oxygen upon light irradiation to oxidize Mn(II) to Mn(III), which is confirmed by a suite of spectroscopic evidence. The in situ produced Mn(III) acts as a mediator, analogous to mediators in electrochemistry to enhance electron transfer. None of the other divalent metal ions show such an effect, allowing the selective detection of Mn(II) down to 5 nM. EDTA further enhances the activity by stabilizing the highly active Mn(III), producing an intense blue color by oxidizing 3,3′,5,5′-tetramethylbenzidine (TMB) in just 10 s. Finally, this reaction was used to evaluate antioxidants. With this method, more analytical and biomedical applications of nanozymes can be exploited at neutral pH, and it may inspire other strategies to overcome the pH limitation in nanozyme catalysis.
Materials for photosensitized oxygen activation are extremely important for a suite of photodynamic applications in biomedical, analytical, and energy sectors. Carbon-based photosensitizers are ...attractive for their low cost and high stability, but most of them such as fullerene and graphene quantum dots suffer from low efficiency, and the rational design of carbon-based photosensitizers remains a challenge. Given the similar chemical origin of phosphorescence and photosensitization, we herein synthesized a series of nitrogen-doped carbon dots (C-dots) and confirmed that their photo-oxidation activity correlated with their phosphorescence quantum yields, providing a direction for the rational designing of such materials. Compared to other carbon nanomaterials and molecular photosensitizers, these C-dots have the highest activity, and they can finish oxidation reactions in a few seconds. The excellent photosensitized oxygen activation makes these water-soluble C-dots a promising oxidase-mimicking nanozyme for photodynamic antimicrobial chemotherapy and other applications.
This paper investigates the problems of impulsive stabilization and impulsive synchronization of discrete-time delayed neural networks (DDNNs). Two types of DDNNs with stabilizing impulses are ...studied. By introducing the time-varying Lyapunov functional to capture the dynamical characteristics of discrete-time impulsive delayed neural networks (DIDNNs) and by using a convex combination technique, new exponential stability criteria are derived in terms of linear matrix inequalities. The stability criteria for DIDNNs are independent of the size of time delay but rely on the lengths of impulsive intervals. With the newly obtained stability results, sufficient conditions on the existence of linear-state feedback impulsive controllers are derived. Moreover, a novel impulsive synchronization scheme for two identical DDNNs is proposed. The novel impulsive synchronization scheme allows synchronizing two identical DDNNs with unknown delays. Simulation results are given to validate the effectiveness of the proposed criteria of impulsive stabilization and impulsive synchronization of DDNNs. Finally, an application of the obtained impulsive synchronization result for two identical chaotic DDNNs to a secure communication scheme is presented.
Composting is an efficient way to convert organic waste into fertilizers. However, waste materials often contain large amounts of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) ...that can reduce the efficacy of antibiotic treatments when transmitted to humans. Because conventional composting often fails to remove these compounds, we evaluated if hyperthermophilic composting with elevated temperature is more efficient at removing ARGs and MGEs and explored the underlying mechanisms of ARG removal of the two composting methods. We found that hyperthermophilic composting removed ARGs and MGEs more efficiently than conventional composting (89% and 49%, respectively). Furthermore, the half-lives of ARGs and MGEs were lower in hyperthermophilic compositing compared to conventional composting (67% and 58%, respectively). More-efficient removal of ARGs and MGEs was associated with a higher reduction in bacterial abundance and diversity of potential ARG hosts. Partial least-squares path modeling suggested that reduction of MGEs played a key role in ARG removal in hyperthermophilic composting, while ARG reduction was mainly driven by changes in bacterial community composition under conventional composting. Together these results suggest that hyperthermophilic composting can significantly enhance the removal of ARGs and MGEs and that the mechanisms of ARG and MGE removal can depend on composting temperature.
Fluorescence imaging in the second near‐infrared window (NIR‐II) is a new technique that permits visualization of deep anatomical features with unprecedented spatial resolution. Although attractive, ...effectively suppressing the interference signal of the background is still an enormous challenge for obtaining target‐specific NIR‐II imaging in the complex and dynamic physiological environment. Herein, dual‐pathological‐parameter cooperatively activatable NIR‐II fluorescence nanoprobes (HISSNPs) are developed whereby hyaluronic acid chains and disulfide bonds act as the “double locks” to lock the fluorescence‐quenched aggregation state of the NIR‐II fluorescence dyes for performing ultrahigh specific imaging of tumors in vivo. The fluorescence can be lit up only when the “double locks” are opened by reacting with the “dual smart keys” (overexpressed hyaluronidase and thiols in tumor) simultaneously. In vivo NIR‐II imaging shows that they reduce nonspecific activitation and achieve ultralow background fluorescence, which is 10.6‐fold lower than single‐parameter activatable probes (HINPs) in the liver at 15 h postinjection. Consequently, these “dual lock‐and‐key”‐controlled HISSNPs exhibit fivefold higher tumor‐to‐normal tissue ratio than “single lock‐and‐key”‐controlled HINPs at 24 h postinjection, attractively realizing ultrahigh specificity of tumor imaging. This is thought to be the first attempt at implementing ultralow background interference with the participation of multiple pathological parameters in NIR‐II fluorescence imaging.
Dual‐pathological‐parameter cooperatively activatable nanoprobes, using a “dual lock‐and‐key” strategy, are constructed to adjust their aggregation degree for ultrahigh specific fluorescence imaging in the second near‐infrared window (NIR‐II). These nanoprobes based on self‐assembled NIR‐II dye‐pendent hyaluronans require the simultaneous presence of dual pathogens (hyaluronidase/thiols) to activate NIR‐II fluorescence. Thus, they significantly suppress the background signal, causing the ultrahigh specificity of tumor imaging.
The role of circular RNAs (circRNAs) in coronary artery disease (CAD) remains elusive. The aim of the present study was to profile circRNAs expression in CAD patients and assess diagnostics ...biomarkers for CAD.
The circRNA profiles of 24 CAD patients and 7 controls were assessed by microarray. The expression levels of candidate circRNAs were further verified by qRT-PCR in large cohorts. Logistic regression analysis and receiver operating characteristic were conducted to assess the diagnostic value. Gain-of-function approach was used to determine the functional significance of validated circRNA in THP-1-derived macrophages.
A total of 624 circRNAs and 171 circRNAs were significantly upregulated and downregulated, respectively, in CAD patients relative to controls. Hsa_circ_0001879 and hsa_circ_0004104 were validated to be significantly upregulated in large cohorts. The receiver operating characteristics analysis of hsa_circ_0001879 and hsa_circ_0004104 in CAD patients and controls showed that the area under curve was 0.703 (95% confidence interval: 0.656–0.750; p < 0.001) and 0.700 (95% confidence interval: 0.646–0.755; p < 0.001), respectively. The combination of hsa_circ_0001879 and hsa_circ_0004104, together with CAD risk factors, had the better performance to discriminate CAD patients from healthy controls. Overexpression of hsa_circ_0004104 resulted in dysregulation of atherosclerosis-related genes in THP-1-derived macrophages.
We offered a transcriptome-wide overview of aberrantly expressed circRNAs in CAD patients and identified two novel circRNA biomarkers to diagnose CAD. Upregulation of hsa_circ_0004104 might contribute to the pathogenesis of CAD.
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•We offered a transcriptome-wide overview of aberrantly expressed circRNAs in CAD patients.•hsa_circ_0001879 and hsa_circ_0004104 were identified as novel circRNA biomarkers for diagnosing CAD.•Hsa_circ_0004104 might contribute to the pathogenesis of atherosclerosis and CAD by regulating atherosclerosis related genes expression.
Whispering‐gallery‐mode (WGM) resonators of semiconductor microdisks have been applied for achieving low‐threshold and narrow‐linewidth microlasers, but require sophisticated top‐down processing ...technology. Organic single‐crystalline hexagonal microdisks (HMDs) of p‐distyrylbenzene (DSB) self‐assembled from solution can function as WGM microresonators with a cavity quality factor (Q) of 210. Both multiple‐ and single‐mode lasing had been achieved using DSB HMDs with an edge length of 4.3 and 1.2 μm, respectively. These organic microdisks fabricated by bottom‐up self‐assembly approach may offer potential applications as low‐threshold microlaser sources for photonic circuit integration.
Organic microlasers: Organic hexagonal microdisks were fabricated by a facile solution self‐assembly method. Whispering‐gallery‐mode (WGM) laser action was observed in these organic hexagonal microdisks (see picture). These microdisks contribute to the miniaturization of laser sources and integration of photonic devices.
In order to promote preclinical and clinical applications of photoacoustic imaging, novel photoacoustic contrast agents are highly desired for molecular imaging of diseases, especially for deep tumor ...imaging. Here, perylene‐3,4,9,10‐tetracarboxylic diiimide‐based near‐infrared‐absorptive organic nanoparticles are reported as an effi cient agent for photoacoustic imaging of deep brain tumors in living mice with enhanced permeability and retention effect.
Near-infrared (NIR) lasers are key components for applications, such as telecommunication, spectroscopy, display, and biomedical tissue imaging. Inorganic III–V semiconductor (GaAs) NIR lasers have ...achieved great successes but require expensive and sophisticated device fabrication techniques. Organic semiconductors exhibit chemically tunable optoelectronic properties together with self-assembling features that are well suitable for low-temperature solution processing. Major blocks in realizing NIR organic lasing include low stimulated emission of narrow-bandgap molecules due to fast nonradiative decay and exciton–exciton annihilation, which is considered as a main loss channel of population inversion for organic lasers under high carrier densities. Here we designed and synthesized the small organic molecule (E)-3-(4-(di-p-tolylamino)phenyl)-1-(1-hydroxynaphthalen-2-yl)prop-2-en-1-one (DPHP) with amphiphilic nature, which elaborately self-assembles into micrometer-sized hemispheres that simultaneously serves as the NIR emission medium with a photoluminescence quantum efficiency of ∼15.2%, and the high-Q (∼1.4 × 103) whispering gallery mode microcavity. Moreover, the radiative rate of DPHP hemispheres is enhanced up to ∼1.98 × 109 s–1 on account of the exciton-vibrational coupling in the solid state with the J-type molecular-coupling component, and meanwhile the exciton–exciton annihilation process is eliminated. As a result, NIR lasing with a low threshold of ∼610 nJ/cm2 is achieved in the single DPHP hemisphere at room temperature. Our demonstration is a major step toward incorporating the organic coherent light sources into the compact optoelectronic devices at NIR wavelengths.
The influence of Stokes shift in optosensing was discussed. Then, the current status of large Stokes shift-based optosensing was reviewed here.
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Stokes shift is an important feature of ...fluorescence, which reveals the energy loss between the excitation and the emission. For most fluorescent materials (e.g., organic dyes and proteins), the large overlap between the absorption and emission spectra endow them a small Stokes shift that induced reabsorption by fluorophore itself. Although the self-absorption can be effectively reduced due to the emergence of fluorescent nanomaterials, fluorescence attenuation is still observed in aggregated or concentrated nanocrystals, causing reduced sensitivity of biosensors. Therefore, increasing the Stokes shift can effectively improve the performance of nano-agents based biosensing. In this critical review, through understanding the Stokes shift from the viewpoint of self-absorption, the influence of Stokes shift on fluorescence properties are discussed. Based on the principle of changing the Stokes shift of fluorescent nanomaterials, we described the methods for constructing various optically large Stokes shift-based nanomaterials, and the application of these nanocrystals in biosensing is especially concerned in this review.
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