Supramolecular Aggregation of Carbon Nanodots.

Supramolecular aggregation has provided the archetype concept to understand the variants in an emerging systems property. Herein, we have achieved the supramolecular assembly of carbon nanodots (CDs) for the first time and employ supramolecular aggregation to understand their alteration in photophysical properties. In detail, we have employed the CDs as a block to construct the supramolecular assembly of aggregates in the CDs' antisolvent of ethanol. The CD-based aggregates exhibit complex and organized morphologies with another long-wavelength excitation-dependent emission band. The experimental results and density functional theoretical calculations reveal that the supramolecular assembly of CDs can decrease the energy gap between the ground and excited states, contributing to the new long-wavelength excitation-dependent emission. The supramolecular aggregation can be employed as one universal strategy to manipulate and understand the luminescence of CDs. These findings cast new light to build the emerging systems and understand the light emission of CDs through supramolecular chemistry.

In Situ Confining Citric Acid-Derived Carbon Dots for Full-Color Room-Temperature Phosphorescence.

Room-temperature phosphorescence has received much attention owing to its potential applications in information encryption and bioelectronics. However, the preparation of full-color single-component-derived phosphorescent materials remains a challenge. Herein, a facile in situ confining strategy is proposed to achieve full-color phosphorescent carbon dots (CDs) through rapid microwave-assisted carbonization of citric acid in NaOH. By tuning the mass ratio of citric acid and NaOH, the obtained CDs exhibit tunable phosphorescence wavelengths ranging from 483 to 635 nm and alterable lifetimes from 58 to 389 ms with a synthesis yield of up to 83.7% (>30 g per synthesis). Theoretical calculations and experimental results confirm that the formation of high-density ionic bonds between cations and CDs leads to efficient afterglow emission via the dissociation of CD arrangement, and the evolution of the aggregation state of CDs results in redshifted phosphorescence. These findings provide a strategy for the synthesis of new insights into achieving and manipulating room-temperature phosphorescent CDs, and prospect their applications in labeling and information encryption.

Identification of an m6A-related lncRNA prognostic signature in colorectal cancer.

Data sets of colorectal cancer (CRC) were obtained from The Cancer Genome Atlas (TCGA), three N6-methyladenosine (m6A) subtypes were identified using 21 m6A-related long noncoding RNAs (lncRNAs) and differential m6A subtypes of different CRC tumors were determined in this study to evaluate the m6A expression and the prognosis of patients with CRC. Subsequently, eight key lncRNAs were identified based on co-expression with 21 m6A-related genes in CRC tumors using the single-factor Cox and least absolute shrinkage and selection operator. Finally, an m6A-related lncRNA risk score model of CRC tumor was established using multifactor Cox regression based on the eight important lncRNAs and found to have a better performance in evaluating the prognosis of patients in the TCGA-CRC data set. TCGA-CRC tumor samples were divided based on the risk scores: high and low. Then, the clinical characteristics, tumor mutation load, and tumor immune cell infiltration difference between the high- and low-risk-score groups were explored, and the predictive ability of the risk score was assessed for immunotherapeutic benefits. We found that the risk score model can determine the overall survival, be a relatively independent prognostic indicator, and better evaluate the immunotherapeutic benefits for patients with CRC. This study provides data support for accurate immunotherapy in CRC.

Broadband Negative Photoconductive Response in Carbon Nanodots.

Due to the broadband response and low selectivity of external light, negative photoconductivity (NPC) effect holds great potential applications in photoelectric devices. Herein, different photoresponsive carbon nanodots (CDs) are prepared from diverse precursors and the broadband response from the NPC CDs are utilized to achieve the optoelectronic logic gates and optical imaging for the first time. In detail, the mcu-CDs which are prepared by the microwave-assisted polymerization of citric acid and urea possess the large specific surface area and abundant hydrophilic groups as sites for the adsorption of H2O molecules and thereby present a high conductivity in dark. Meanwhile, the low affinity of mcu-CDs to H2O molecules permits the light-induced desorption of H2O molecules by heat effect and thus endow the mcu-CDs with a low conductivity under illumination. The easy absorption and desorption of H2O molecules contribute to the extraordinary NPC of mcu-CDs. With the broadband NPC response in CDs, the optoelectronic logic gates and flexible optical imaging system are established, achieving the applications of "NOR" or "NAND" logic operations and high-quality optical images. These findings unveil the unique optoelectronic properties of CDs, and have the potential to advance the applications of CDs in optoelectronic devices.

Photooxidation triggered ultralong afterglow in carbon nanodots.

It remains a challenge to obtain biocompatible afterglow materials with long emission wavelengths, durable lifetimes, and good water solubility. Herein we develop a photooxidation strategy to construct near-infrared afterglow carbon nanodots with an extra-long lifetime of up to 5.9 h, comparable to that of the well-known rare-earth or organic long-persistent luminescent materials. Intriguingly, size-dependent afterglow lifetime evolution from 3.4 to 5.9 h has been observed from the carbon nanodots systems in aqueous solution. With structural/ultrafast dynamics analysis and density functional theory simulations, we reveal that the persistent luminescence in carbon nanodots is activated by a photooxidation-induced dioxetane intermediate, which can slowly release and convert energy into luminous emission via the steric hindrance effect of nanoparticles. With the persistent near-infrared luminescence, tissue penetration depth of 20 mm can be achieved. Thanks to the high signal-to-background ratio, biological safety and cancer-specific targeting ability of carbon nanodots, ultralong-afterglow guided surgery has been successfully performed on mice model to remove tumor tissues accurately, demonstrating potential clinical applications. These results may facilitate the development of long-lasting luminescent materials for precision tumor resection.

Chemiluminescent carbon nanodots for dynamic and guided antibacteria.

Advanced antibacterial technologies are needed to counter the rapid emergence of drug-resistant bacteria. Image-guided therapy is one of the most promising strategies for efficiently and accurately curing bacterial infections. Herein, a chemiluminescence (CL)-dynamic/guided antibacteria (CDGA) with multiple reactive oxygen species (ROS) generation capacity and chemiexcited near-infrared emission has been designed for the precise theranostics of bacterial infection by employing near-infrared emissive carbon nanodots (CDs) and peroxalate as CL fuels. Mechanistically, hydrogen peroxide generated in the bacterial microenvironment can trigger the chemically initiated electron exchange between CDs and energy-riched intermediate originated from the oxidized peroxalate, enabling bacterial induced inflammation imaging. Meanwhile, type I/II photochemical ROS production and type III ultrafast charge transfer from CDs under the self-illumination can inhibit the bacteria proliferation efficiently. The potential clinical utility of CDGA is further demonstrated in bacteria infected mice trauma model. The self-illuminating CDGA exhibits an excellent in vivo imaging quality in early detecting wound infections and internal inflammation caused by bacteria, and further are proven as efficient broad-spectrum antibacterial nanomedicines without drug-resistance, whose sterilizing rate is up to 99.99%.

Recent progress of carbon dots in targeted bioimaging and cancer therapy.

Carbon dots (CDs), as one new class of carbon nanomaterials with various structure and extraordinary physicochemical properties, have attracted tremendous interest for their potential applications in tumor theranostics, especially in targeted bioimaging and therapy. In these areas, CDs and its derivatives have been employed as highly efficient imaging agent for photoluminescence bioimaging of tumors cells. With unique structure, optical and/or dose attention properties, CDs have been harnessed in various nanotheranostic strategies for diverse tumors through integrating with other functional nanoparticles or utilizing their inherent physical properties. Up to now, CDs have been approved as novel biomaterials by their excellent performances in precise targeted bioimaging and therapy for tumors. Herein, the latest progress in the development of CDs in targeted bioimaging and tumor therapy are reviewed. Meanwhile, the challenges and future prospects of the application of CDs in promising nanotheranostic strategies are discussed and proposed.

Identification of a Prognostic Colorectal Cancer Model Including LncRNA FOXP4-AS1 and LncRNA BBOX1-AS1 Based on Bioinformatics Analysis.

Background: Knowledge about the prognostic role of long noncoding RNA (lncRNA) in colorectal cancer (CRC) is limited. Therefore, we constructed a lncRNA-related prognostic model based on data from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA). Materials and Methods: CRC transcriptome and clinical data were downloaded from the GSE20916 dataset and the TCGA database, respectively. R software was used for data processing and analysis. The differential lncRNA expression within the two datasets was first screened, and then intersections were measured. Cox regression and the Kaplan-Meier method were used to evaluate the effects of various factors on prognosis. The area under the curve (AUC) of the receiver operating characteristic curve and a nomogram based on multivariate Cox analysis were used to estimate the prognostic value of the lncRNA-related model. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were applied to elucidate the significantly involved biological functions and pathways. Results: A total of 11 lncRNAs were crossed. The univariate Cox analysis screened out two lncRNAs, which were analyzed in the multivariate Cox analysis. A nomogram based on the two lncRNAs and other clinicopathological risk factors was constructed. The AUC of the nomogram was 0.56 at 3 years and 0.71 at 5 years. The 3-year nomogram model was compared with the ideal model, which showed that some indices of the 3-year model were consistent with the ideal model, suggesting that our model was highly accurate. The GO and KEGG enrichment analyses showed that positive regulation of secretion by cells, positive regulation of secretion, positive regulation of exocytosis, endocytosis, and the calcium signaling pathway were differentially enriched in the two-lncRNA-associated phenotype. Conclusions: A two-lncRNA prognostic model of CRC was constructed by bioinformatics analysis. The model had moderate prediction accuracy. LncRNA BBOX1-AS1 and lncRNA FOXP4-AS1 were identified as prognostic biomarkers.

Meter-scale chemiluminescent carbon nanodot films for temperature imaging.

Chemiluminescence (CL), as one class of luminescence driven by chemical reaction, exhibits obvious temperature-dependence in its light emission process. Herein, temperature-dependent CL emission of carbon nanodots (CDs) in the chemical reaction of peroxalate and hydrogen peroxide is demonstrated and temperature imaging based on the temperature-dependent CL has been established for the first time. In detail, the temperature-dependent CL emission of CDs in the chemical reaction of peroxalate and hydrogen peroxide is observed, and the linear relationship between the CL intensity and temperature is demonstrated in both the CL solution and film, enabling their applications in temperature sensing and imaging capabilities. The increase of the CL emission with temperature can be attributed to the accelerated electron exchange between the CDs and intermediate generated in the peroxalate system. Meter-scale chemiluminescent CD films have been constructed. The CL sensor based on the films presents a high spatial resolution of 0.4 mm and an outstanding sensitivity of 0.08 °C-1, which is amongst the best values for the thermographic luminophores. With the unique temperature response and flexible properties, non-planar, meter-scale and sensitive palm temperature imaging has been achieved. These findings present new opportunities for designing CL-based temperature probes and thermography.

Near-Infrared Chemiluminescent Carbon Nanodots and Their Application in Reactive Oxygen Species Bioimaging.

Reactive oxygen species (ROS) are generated in the body and related to many pathophysiological processes. Hence, detection of ROS is indispensable in understanding, diagnosis, and treatment of many diseases. Here, near-infrared (NIR) chemiluminescent (CL) carbon nanodots (CDs) are fabricated for the first time and their CL quantum yield can reach 9.98 × 10-3 einstein mol-1, which is the highest value ever reported for CDs until now. Nanointegration of NIR CDs and peroxalate (P-CDs) through the bridging effect of amphiphilic triblock copolymer can serve as turn-on probes for the detection and imaging of hydrogen peroxide (H2O2). Considering high efficiency and large penetration depth of NIR photons, the P-CDs are employed in bioimaging H2O2 in vitro and in vivo, and the detection limit can reach 5 × 10-9 m, among the best reported of CDs-based sensors. Moreover, imaging of inflammatory H2O2 in a mouse model of peritonitis is achieved by employing the P-CDs as sensors. The results may provide a clue for the diagnosis and treatment of inflammation or cancers employing CL CDs as sensors.

Bright and Multicolor Chemiluminescent Carbon Nanodots for Advanced Information Encryption.

The various luminescent properties of carbon nanodots (CDs) reveal fascinating applications in several areas. Here, bright and multicolor chemiluminescence (CL) is realized from CDs, whose CL quantum yield can be optimized by adjusting the energy level alignment between the CDs and 1,2-dioxetanedione intermediate generated from the reaction of peroxalate and hydrogen peroxide. A CL quantum yield of 9.32 × 10-3 Einsteins mol-1, maximal luminance of 3.28 cd m-2, and lifetime of 186.4 s are achieved in red CDs, all of which are the best values ever reported for CDs. As a proof-of-concept prototype, a high-quality information encryption strategy is established via CD based CL imaging techniques by virtue of the high brightness and multicolor CL.

miR-133a-3p Targets SUMO-Specific Protease 1 to Inhibit Cell Proliferation and Cell Cycle Progress in Colorectal Cancer.

Dysregulation of SUMO-specific protease 1 (SENP1) expression has been reported in several kinds of cancer, including human colorectal and prostate cancers, proposing SENP1 as an oncogene with a critical role in cancer progression. miR-133a-3p has been reported as a tumor suppressor in several malignant neoplasias. However, the precise molecular mechanisms underlying its role in colorectal cancer remain largely unknown. The aim of this work was to investigate the relationship between miR-133a-3p and SENP1 in colorectal cancer cells. We found that miR-133a-3p expression was downregulated in colorectal cancer tissues. In silico analyses indicated that SENP1 is one of the target genes of miR-133a-3p. Overexpression of miR-133a-3p mimics was able to inhibit cell growth with G1 arrest of colorectal cancer cells. Overexpression of miR-133a-3p antisense promoted cell growth of colorectal cancer cells. The luciferase reporter experiments showed that miR-133a-3p regulated the expression of SENP1 by combining with its 3'-UTR and resulted in downregulation of SENP1 and upregulation of CDK inhibitors such as p16, p19, p21, and p27. These results suggest that the miR-133a-3p-SENP1 axis might play a role in cell proliferation and cell cycle regulation of colorectal cancer cells.

Carbon Nanodots as Dual-Mode Nanosensors for Selective Detection of Hydrogen Peroxide.

Hydrogen peroxide (H2O2) is an important product of oxidase-based enzymatic reactions, such as glucose/glucose oxidase (GOD) reaction. Therefore, the probing of generated H2O2 for achieving the detection of various carbohydrates and their oxidases is very significative. Herein, we report one kind of dual-emission carbon nanodots (CDs) that can serve as novel dual-mode nanosensors with both fluorometric and colorimetric output for the selective detection of H2O2. The dual-model nanosensors are established only by the undecorated dual-emission CDs, where significant fluorometric and colorimetric changes are observed with the addition of different concentrations of H2O2 in the CD solution, which benefit to the achievement of the naked-eye detection for H2O2. The mechanism of the nanosensors can be attributed to the fact that the external chemical stimuli like hydroxyl radicals from H2O2 bring about the change of surface properties and the aggregation of CDs, which dominate the emission and absorption of CDs. The constructed dual-mode nanosensors exhibit good biocompatibility and high selectivity toward H2O2 with a linear detection range spanning from 0.05 to 0.5 M and allow the detection of H2O2 as low as 14 mM.