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An effective wound management strategy needs accurate assessment of wound status throughout the whole healing process. This can be achieved by examining molecular biomarkers including proteins, DNAs, and RNAs. However, existing methods for quantifying these biomarkers such as immunohistochemistry and quantitative polymerase chain reaction are usually laborious, resource‐intensive, and disruptive. This article reports the development and utilization of mRNA nanosensors (i.e., NanoFlare) that are topically applied on cutaneous wounds to reveal the healing status through targeted and semi‐quantitative examination of the mRNA biomarkers in skin cells. In 2D and 3D in vitro models, the efficacy and efficiency of these nanosensors are demonstrated in revealing the dynamic changes of mRNA biomarkers for different stages of wound development. In mouse models, this platform permits the tracking and identification of wound healing stages and a normal and diabetic wound healing process by wound healing index in real time. [ABSTRACT FROM AUTHOR]

Abstract An effective wound management strategy needs accurate assessment of wound status throughout the whole healing process. This can be achieved by examining molecular biomarkers including proteins, DNAs, and RNAs. However, existing methods for quantifying these biomarkers such as immunohistochemistry and quantitative polymerase chain reaction are usually laborious, resource‐intensive, and disruptive. This article reports the development and utilization of mRNA nanosensors (i.e., NanoFlare) that are topically applied on cutaneous wounds to reveal the healing status through targeted and semi‐quantitative examination of the mRNA biomarkers in skin cells. In 2D and 3D in vitro models, the efficacy and efficiency of these nanosensors are demonstrated in revealing the dynamic changes of mRNA biomarkers for different stages of wound development. In mouse models, this platform permits the tracking and identification of wound healing stages and a normal and diabetic wound healing process by wound healing index in real time.

Nanoflares and the shock formation of magnetohydrodynamic waves in the solar chromosphere have been considered as key physical mechanisms of the heating of the chromosphere and corona. To investigate candidates of their signature in the mm-wavelength, a tiny active region located on the solar disk was observed with the Atacama Large millimeter and sub-millimeter Array (ALMA) at 3 mm, coordinated with observatories on orbit including Hinode SOT spectro-polarimeter in the Cycle 4 solar campaign (19 March 2017). ALMA’s spatial resolution was moderate, far from the best performance, but it provided stable conditions that are suitable to investigate temporal variations in the mm-wavelength. We determined that the noise level is less than 20 K (σ) over 1 hour in the 20-s cadence time series of synthesized ALMA images. The time variations with amplitudes above the noise level were observed throughout the field of view, but variations exceeding 200 K, corresponding to energy input to the chromosphere on the order of 1020-22 erg, were localized in two locations. One location was on the polarity inversion line, where tiny concentrated magnetic patches exist in weak field and a tiny magnetic flux may be emergent. The other location was at the outer edge of a bipolar magnetic region, which was under development with a successive series of magnetic flux emergence. This observation suggests that nanoflare-class energy inputs in the chromosphere can occur associated with emerging flux activities.

Exosomal miRNAs can reflect tumor progression and metastasis, and are effective biomarkers for cancer diagnosis. However, the accuracy of exosomal miRNA-based cancer diagnosis is limited by the low sensitivity and complicated RNA extraction of traditional approaches. Herein, a novel biosensor is developed for in situ, extraction-free, and highly sensitive analysis of exosomal miRNAs via nanoflare combined with catalyzed hairpin assembly (CHA) amplification. Without cumbersome and costly miRNA extraction or transfection agents, nanoflare can directly enter the exosomes to bind target miRNAs and generate a fluorescence signal that can be amplified by the CHA reaction to achieve the in situ and highly sensitive detection of exosomal miRNAs. Under the optimal conditions, the detection limit of 5 aM is obtained for three exosomal miRNAs, which is an order of magnitude lower than quantitative real time polymerase chain reaction (qRT-PCR). In combination with the linear discriminant analysis algorithm, five exosomes are distinguished with 100% accuracy. Importantly, five cancers including breast, lung, liver, cervical, and colon cancer from 64 patients are distinguished with 99% accuracy by testing exosomal miRNAs in clinical plasma. This simple, accurate, and sensitive biosensor holds the potential to be expanded into clinical non-invasive cancer diagnostic tests. [Display omitted] • Nanoflare&CHA enables in situ and sensitive detection of exosomal miRNAs. • The LOD is 5 aM of exosomal miRNA, which is an order of magnitude lower than qRT-PCR. • A clinical cohort of 64 patients were successfully predicted with 99% accuracy. [ABSTRACT FROM AUTHOR]

How to in situ detect intracellular telomerase activity with high sensitivity still faces many challenges. This paper constructs a new fluorescence biosensing platform for the sensitive detection of intracellular telomerase activity via the combination of nanoflare and hybridization chain reaction (HCR)-based signal amplification on a single patchy gold/carbon nanosphere (PG/CNS), which has two or more distinct parts and allows hybridized-DNA (HS-DNA/Primer-DNA/Flare-DNA) and H1/H2-DNA (a pair of cross complementary DNA hairpins) to bind onto their surfaces via Au–S bond and electrostatic interaction, respectively. In the presence of telomerase, Primer-DNA (telomerase primer) extends at its 3′ end to produce a telomeric repeated sequence, resulting in the release of Flare-DNA followed by the recovery of the fluorescence. Subsequently, the released Flare-DNA further initiates cross hybridization of H1 and H2 DNA from mimic-HCR system to amplify the fluorescence signal. The in vivo confocal microscopy studies demonstrate that resulting sensor can enter into the cancer cells such as A549 cells, and lead to the increase in luminescence, which is stronger than the sensor without the HCR-based signal amplification system. A linear relationship between the fluorescence intensity and the amount of A549 cells is observed, and the limit of detection of the sensor reaches about 280 A549 cells. Image 1 • Fluorescence biosensor for detecting telomerase using PG/CNSs with Janus structure. • The oligonucleotides on the surface of PG/CNSs are highly resistant to DNase I. • The sensor can in situ detect intracellular telomerase activity with high sensitivity. • The detection limit of sensor reaches about 280 A549 cells. [ABSTRACT FROM AUTHOR]

Nanoflares are the small impulsive sudden energy releases, due to the explosion of solar background. Thus, determination of their energies and distributions is important . Recent observations and simulation models have shown that the frequency of their energies follows power-law. According to Parker hypothesis, if these exponents are greater than critical value 2, the contributions of nanoflares to the heating of solar corona is more significan. Here, the extreme ultra-violet (EUV) emission radiances of corona observed by STEREO/EUVI taken on 11 and 12 Jun 2007 are analyzed. To simulate the EUV irradiance, a simple nanoflare model with three key parameters (the flare rate, the flare duration time, and the exponent of the power- law) is applied. Based on genetic algorithm, the lengths of data points are reduced. The resultant light curves are fed to the Support Vector Machine (SVM) classifier. The produced light curves of quiet and active regions of the solar corona are classified and the set of power- law exponent, the flare duration time and the flare rate parameters are obtained. The flare duration time is estimated about 80 minutes. The power-low exponents range about 2.5-2.7.

Background: One of the most challenging tasks of modern biology concerns the real-time tracking and quantification of mRNA expression in living cells. On this matter, a novel platform called SmartFlare TM has taken advantage of fluorophore-linked nanoconstructs for targeting RNA transcripts. Although fluorescence emission does not account for the spatial mRNA distribution, NanoFlare technology has grown a range of theranostic applications starting from detecting biomarkers related to diseases, such as cancer, neurodegenerative pathologies or embryonic developmental disorders., Aim: To investigate the potential of SmartFlare TM in determining time-dependent mRNA expression of prominin 1 ( CD133 ) and octamer-binding transcription factor 4 ( OCT4 ) in single living cells through differentiation., Methods: Brain fragments from the striatum of aborted human fetuses aged 8 wk postconception were processed to obtain neurospheres. For the in vitro differentiation, neurospheres were gently dissociated with Accutase solution. Single cells were resuspended in a basic medium enriched with fetal bovine serum, plated on poly-L-lysine-coated glass coverslips, and grown in a lapse of time from 1 to 4 wk. Live cell mRNA detection was performed using SmartFlare TM probes (CD133, Oct4, Actin, and Scramble). All the samples were incubated at 37 °C for 24 h. For nuclear staining, Hoechst 33342 was added. SmartFlare TM CD133- and OCT4-specific fluorescence signal was assessed using a semiquantitative visual approach, taking into account the fluorescence intensity and the number of labeled cells., Results: In agreement with previous PCR experiments, a unique expression trend was observed for CD133 and OCT4 genes until 7 d in vitro (DIV). Fluorescence resulted in a mixture of diffuse cytoplasmic and spotted-like pattern, also detectable in the contacting neural branches. From 15 to 30 DIV, only few cells showed a scattered fluorescent pattern, in line with the differentiation progression and coherent with mRNA downregulation of these stemness-related genes., Conclusion: SmartFlare TM appears to be a reliable, easy-to-handle tool for investigating CD133 and OCT4 expression in a neural stem cell model, preserving cell biological properties in anticipation of downstream experiments., Competing Interests: Conflict-of-interest statement: The authors declare that they have no conflict of interest., (©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.)

Drug-induced nephrotoxicity represents an important cause of acute kidney injury with associated patient morbidity and mortality and is often responsible for termination of drug development, after extensive resource allocation. We have developed a human kidney tubuloid system that phenocopies, in 3D culture, kidney proximal tubules, a primary injury site of most nephrotoxicants. Traditional end point assays are often performed on 2D cultures of cells that have lost their differentiated phenotype. Herein, we pair a tubuloid system with Nanoflare (NF) mRNA nanosensors to achieve a facile, real-time assessment of drug nephrotoxicity. Using kidney injury molecule-1 (KIM-1) mRNA as a model injury biomarker, we verify NF specificity in engineered and adenovirus-transfected cells and confirm their efficacy to report tubular cell injury by aristolochic acid and cisplatin. The system also facilitates nephrotoxicity screening as demonstrated with 10 representative anticancer moieties. 5-Fluorouracil and paclitaxel induce acute tubular injury, as reflected by an NF signal increase.

Accurate tumor margin demarcation in situ remains a paramount challenge. Herein, a NanoFlare (also known as spherical-nucleic-acid technology) based strategy is reported for in situ tumor margin delineation by transforming and amplifying the pathophysiological redox signals of tumor microenvironment. The NanoFlare designed (named AuNS-ASON) is based on gold nanostar (AuNS) coated with a dense shell of disulfide bridge-inserted and cyanine dyes-labeled antisense oligonucleotides (ASON) targeting survivin mRNA. The unique anisotropic ASON-spike nanostructure endows the AuNS-ASON with universal cellular internalization of tumor cells, while the disulfide bridge inserted confers response specificity toward redox activation. In vitro experiments demonstrate that the AuNS-ASON can discriminate tumor cells rapidly with activated fluorescence signals (>100-fold) in 2 h, and further achieve synergistic gene/photothermal tumor cells ablation upon near-infrared laser irradiation. Remarkably, in situ tumor margin delineation with high accuracy and outstanding spatial resolution (<100 µm) in mice bearing different tumors is obtained based on the AuNS-ASON, providing intraoperative guidance for tumor resection. Moreover, the AuNS-ASON can enable efficient neoadjuvant gene/photothermal therapy before surgery to reduce tumor extent and increase resectability. The concept of NanoFlare-based microenvironment signal transformation and amplification could be used as a general strategy to guide the design of activatable nanoprobes for cancer theranostics., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)