Targeted tumour theranostics in mice via carbon quantum dots structurally mimicking large amino acids

Mannose-Derived Carbon Dots Amplify Microwave Ablation-Induced Antitumor Immune Responses by Capturing and Transferring "Danger Signals" to Dendritic Cells

Hepatocellular carcinoma recurrence and metastasis after microwave ablation (MWA) are challenges in the clinic. This study showed that mannose-derived carbon dots (Man-CDs) could effectively capture several "danger signals" (DS) after MWA treatment and then deliver DS specifically to dendritic cells (DCs). This improved delivery of DS to DCs enhanced the processing and presentation of tumor-associated antigens by DCs. The results demonstrated that intratumoral injection of Man-CDs after MWA therapy elicited a potent tumor-specific immune response and finally led to the effective suppression of both primary and distant tumors. MWA + Man-CD treatment could efficiently reject tumor cell rechallenge in vivo. This study demonstrated that Man-CD nanoparticles are effective adjuvants that can improve MWA therapy by eliciting a tumor-specific immune response.

Transformable Honeycomb-Like Nanoassemblies of Carbon Dots for Regulated Multisite Delivery and Enhanced Antitumor Chemoimmunotherapy

Tumor fibrotic stroma forms complex barriers for therapeutic nanomedicine. Although nanoparticle vehicles are promising in overcoming biological barriers for drug delivery, fibrosis causes hypoxia, immunosuppression and limited immunocytes infiltration, and thus reduces antitumor efficacy of nanosystems. Herein, we report the development of cancer-associated fibroblasts (CAFs) responsive honeycomb-like nanoassemblies of carbon dots (CDs) to spatially program the delivery of multiple therapeutics for enhanced antitumor chemoimmunotherapy. Doxorubicin (DOX) and immunotherapeutic enhancer (Fe ions) are immobilized on the surface of CDs, whereas tumor microenvironment modifier (losartan, LOS) is encapsulated within the mesopores. The drugs-loaded nanoassemblies disassociate into individual CDs to release LOS to mitigate stroma and hypoxia in response to CAFs. The individual CDs carrying DOX and Fe ion efficiently penetrate deep into tumor to trigger intensified immune responses. Our in vitro and in vivo studies show that the nanoassemblies exhibit effective T cells infiltration, tumor growth inhibition and lung metastasis prevention, thereby providing a therapeutic platform for desmoplasia solid tumor.

Multi-scale optoacoustic molecular imaging of brain diseases

The ability to non-invasively visualize endogenous chromophores and exogenous probes and sensors across the entire rodent brain with the high spatial and temporal resolution has empowered optoacoustic imaging modalities with unprecedented capacities for interrogating the brain under physiological and diseased conditions. This has rapidly transformed optoacoustic microscopy (OAM) and multi-spectral optoacoustic tomography (MSOT) into emerging research tools to study animal models of brain diseases. In this review, we describe the principles of optoacoustic imaging and showcase recent technical advances that enable high-resolution real-time brain observations in preclinical models. In addition, advanced molecular probe designs allow for efficient visualization of pathophysiological processes playing a central role in a variety of neurodegenerative diseases, brain tumors, and stroke. We describe outstanding challenges in optoacoustic imaging methodologies and propose a future outlook.

Near-infrared Zn-doped Cu2S quantum dots: an ultrasmall theranostic agent for tumor cell imaging and chemodynamic therapy

Theranostic agents that integrated chemodynamic therapy (CDT) and imaging functions have great potential application in personalized cancer therapy. However, most theranostic agents were fabricated by chemically coupling two or more independent functional units with diagnostic or therapeutic capabilities, and therefore have a large size. To date, one-step synthesis of unmodified ultrasmall quantum dots (QDs) integrating CDT and fluorescence imaging capabilities remains a challenge. Herein, we reported a simple one-step synthesis method of ultrasmall (2.46 nm) Zn-doped Cu₂S (Zn:Cu₂S) QDs with inherent properties of both high CDT activity and near-infrared fluorescence imaging capability. The fluorescence of Cu₂S QDs was significantly enhanced approximately tenfold after Zn doping due to the compensation of defects. In vitro and in vivo experiments demonstrated that the Zn:Cu₂S QDs could specifically and significantly inhibit the cancer cell growth (inhibition rate exceeded 65%) without damaging the normal cells. Furthermore, the CDT mechanism study suggested that a Fenton-like reaction occurred after the Zn:Cu₂S QDs entered the tumor cells, inducing apoptosis via the mitochondrial signaling pathway, and activating the production of reactive oxygen species (ROS) and autophagy to selectively eliminate tumor cells to achieve CDT. This work proposed a simple one-step synthesis of unmodified ultrasmall QDs with fluorescence imaging and CDT, which provides a promising strategy for QDs to act as multi-functional theranostic agents.

Rapid and Green Fabrication of Carbon Dots for Cellular Imaging and Anti-Counterfeiting Applications

Carbon dots (CDs) with plenty of favorable properties have been extensively investigated in diverse areas including bioimaging, biomedicine, sensor, energy storage, anti-counterfeiting, photocatalysis, and optoelectronic devices. Herein, a simple, rapid, and green sonochemical-assisted method for fabricating nitrogen-doped CDs has been developed. In this approach, the nitrogen-doped CDs can be obtained through irradiation by intensive ultrasonic waves from ultrasonic probes in 30 min. The achieved CDs exhibit excellent water dispersibility, which can be ascribed to their high functionalization. Importantly, the CDs also demonstrate remarkable fluorescent properties, high photostability, and low cytotoxicity, which can be utilized for multicolor cellular imaging and anti-counterfeiting applications. As far as we know, the sonochemical-assisted method for rapidly synthesizing nitrogen-doped CDs from gelatin has never been reported before. Significantly, the sonochemical-assisted approach to rapidly fabricate CDs is versatile for the facile construction of fluorescent CDs, and the obtained CDs can be potentially used in various areas including bioimaging and anti-counterfeiting.

Enhanced Near-Infrared Emission from Carbon Dots by Surface Deprotonation

Carbon dots (CDs) with efficient excitation and emission in deep-red/near-infrared (NIR) spectral range are important for bioimaging applications. Herein, we develop a simple and effective method to significantly enhance both the absorption and emission of CDs in deep-red/NIR by suppressing nonradiative charge recombination via deprotonation of the CD surface. As compared to aqueous solutions at room temperature, NIR emission of CDs in N,N-dimethylformamide and glycerol experience a 50- and 70-fold increase at -20 °C, respectively, due to enhanced deprotonation ability and viscosity. On the basis of the adjustable NIR fluorescence intensity of CDs, multilevel data encryption in the NIR region is realized by controlling the humidity and the temperature of a CD-ink stamped paper.

Synthesis of color-tunable tannic acid-based carbon dots for multicolor/white light-emitting diodes

Multicolor luminescent carbon dots were successfully prepared by a solvothermal method using tannic acid (TA) and phthalaldehyde.

Facile synthesis of nitrogen-doped carbon dots from pork liver and its sensing of 6-thioguanine based on the inner filter effect

Nitrogen-doped carbon dots were facilely synthesized from pork liver and the fluorescence quenching determination of 6-thioguanine in human serum based on the inner filter effect was achieved with the limit of detection as low as 0.75 μM.

Yellow emission carbon dots for highly selective and sensitive OFF-ON sensing of ferric and pyrophosphate ions in living cells

A simple "OFF-ON" fluorescent system was proposed for selective and sensitive detection of ferric ion (Fe³⁺) and pyrophosphate (PPi) in living cells. The method was constructed based on the bright yellow emission of carbon dots (y-CDs), which were prepared using o-phenylenediamine (OPD) as the precursor via a facile hydrothermal treatment. The as-obtained y-CDs, with an average size of 2.6 nm, exhibited an excitation-independent emission peak at 574 nm. The fluorescence of y-CDs can be remarkably quenched by Fe³⁺ with high selectivity and sensitivity. Interestingly, the quenched fluorescence can be recovered regularly upon addition of PPi, showing a promising detection for PPi. The linear ranges for Fe³⁺ and PPi detections were 0.05-80 and 0.5-120 μM, respectively, and the corresponding limit of detections (LODs) were 22.1 and 73.9 nM. As we proved the y-CDs have negligible cytotoxicity and excellent biocompatibility, further application to the fluorescence imaging of intracellular Fe³⁺ and PPi were conducted, suggesting the prepared y-CDs can be used to monitor Fe³⁺ and PPi variation in living cells. Overall, our developed y-CDs-based OFF-ON switch fluorescent probe has the advantages of simplicity, agility, high sensitivity and selectivity, which provides a promising platform for environmental and biology applications, and paves a new avenue for monitoring the hydrolysis process of adenosine triphosphate disodium salt (ATP) by detection of PPi in organisms.

Carbon Dots: A New Type of Carbon-Based Nanomaterial with Wide Applications

Carbon dots (CDs), as a new type of carbon-based nanomaterial, have attracted broad research interest for years, because of their diverse physicochemical properties and favorable attributes like good biocompatibility, unique optical properties, low cost, ecofriendliness, abundant functional groups (e.g., amino, hydroxyl, carboxyl), high stability, and electron mobility. In this Outlook, we comprehensively summarize the classification of CDs based on the analysis of their formation mechanism, micro-/nanostructure and property features, and describe their synthetic methods and optical properties including strong absorption, photoluminescence, and phosphorescence. Furthermore, the recent significant advances in diverse applications, including optical (sensor, anticounterfeiting), energy (light-emitting diodes, catalysis, photovoltaics, supercapacitors), and promising biomedicine, are systematically highlighted. Finally, we envisage the key issues to be challenged, future research directions, and perspectives to show a full picture of CDs-based materials.

Theranostic Prospects of Graphene Quantum Dots in Breast Cancer

Breast cancer (BC) is increasing as a significant cause of mortality among women. In this context, early diagnosis and treatment strategies for BC are being developed by researchers at the cellular level using advanced nanomaterials. However, immaculate etiquette is the prerequisite for their implementation in clinical practice. Considering the stolid nature of cancer, combining diagnosis and therapy (theranostics) using graphene quantum dots (GQDs) is a prime focus and challenge for researchers. In a nutshell, GQDs is a new shining star among various fluorescent materials, which has acclaimed fame in a short duration in materials science and the biomedical field as well. From this perspective, we review various strategies in BC treatment using GQDs alone or in combination. In addition, the photophysical properties of GQDs explored in photothermal therapy, hyperthermia therapy, and photodynamic therapy are also discussed. Moreover, we also focus on the strategic use of GQDs both as drug carriers and as combinatorial-guided drug delivery motifs. This Review provides an update for the scientific community to plan and expand advanced theranostic horizons in BC using GQDs.

Recent Advances in Nanocarrier-Assisted Therapeutics Delivery Systems

Nanotechnologies have attracted increasing attention in their application in medicine, especially in the development of new drug delivery systems. With the help of nano-sized carriers, drugs can reach specific diseased areas, prolonging therapeutic efficacy while decreasing undesired side-effects. In addition, recent nanotechnological advances, such as surface stabilization and stimuli-responsive functionalization have also significantly improved the targeting capacity and therapeutic efficacy of the nanocarrier assisted drug delivery system. In this review, we evaluate recent advances in the development of different nanocarriers and their applications in therapeutics delivery.