Hydrophobic Mn-Doped Solid-State Red-Emitting Carbon Nanodots with AIE Effect and Their Hydrogel Composites for Color-Changing Anticounterfeiting

Early Diagnosis of Tumorigenesis via Ratiometric Carbon Dots with Deep-Red Emissive Fluorescence Based on NAD+ Dependence

The early diagnosis of tumorigenesis is crucial for clinical treatment, but the resolution and sensitivity of conventional short-wavelength biomarkers are not ideal because of the complicated interference in living tissue. Herein, a nicotinamide adenine dinucleotide (NAD+)-responsive probe with deep-red emissive ratiometric fluorescence was synthetized as a promising target for energy metabolism patterns during tumorigenesis. Interestingly, the solvents H3PO4 and 2,2'-dithiodibenzoic acid enhanced the red emission (640 and 680 nm) of o-phenylenediamine-based carbon dots (CDs), leading to the formation of a nanoscale graphite-like skeleton covered with -P=O, -CONH-, -COOH and -NH2 on their surfaces. Meanwhile, this method exhibited high sensitivity to the discriminating target NAD+, with a detection limit of 63 μM due to the inner filter effect and fluorescence resonance energy transfer process between NAD+ and CDs, which is superior to the reported capillary electrophoresis and liquid chromatographic detection methods (the reported detection limit was about 0.2 mM) in complex biological samples and even cancer cells. Encouragingly, NAD+ significantly promoted nucleus-targeting fluorescence and cell migration compared to GSH and pH stimulation, which were gradually eliminated in human hepatocellular carcinoma (HepG2) cells after 2-deoxy-d-Glucose inhibited the glycolytic phenotype. The proposed method holds great potential for the temporal and spatial resolution of NAD+-dependent tumor diagnosis in complex living systems.

Preparation and Application of a Sulfur-Doped Fluorescent Carbon Dots with Aggregation-Induced Emission Character

As a new type of zero-dimensional nanomaterial, carbon dots are widely applied in various fields. However, most of the carbon dots have aggregation fluorescence quenching properties, which limited their practical applications. In this study, a novel sulfur-doped carbon dots (S-CDs) was prepared by solvothermal method. The properties of the S-CDs in ethanol solution and in solid state were investigated respectively. The results showed that the S-CDs have an excited wavelength dependent emission of blue fluorescence in ethanol solution, and have orange fluorescence emission in solid state and composite films, indicating the prepared S-CDs has aggregation-induced emission (AIE) performance. The main reason was that the presence of S-S bonds and the intramolecular rotation of aromatic rings were limited in solid state, resulting in its emission of orange fluorescence. Furthermore, the S-CDs could be applied to identify fingerprints, anti-counterfeiting.

Dielectric Design of High Dielectric Constant Poly(Urea-Urethane) Elastomer for Low-Voltage High-Mobility Intrinsically Stretchable All-Solution-Processed Organic Transistors

Stretchable organic transistors for skin-like biomedical applications require low-voltage operation to accommodate limited power supply and safe concerns. However, most of the currently reported stretchable organic transistors operate at relatively high voltages. Decreasing their operational voltage while keeping the high mobility still remains a key challenge. Here, the study presents a new dielectric design to achieve high-dielectric constant poly(urea-urethane) (PUU) elastomer, by incorporating a flexible small-molecular diamine crosslinking agent 4-aminophenyl disulfide (APDS) into the main chain of (poly (propylene glycol), tolylene 2,4-diiso-cyanate terminated) (PPG-TDI). Compared with commercial elastomers, the PUU elastomer as dielectric of the stretchable organic transistors shows the outstanding advantages including lower surface roughness (0.33 nm), higher adhesion (45.18 nN), higher dielectric constant (13.5), as well as higher stretchability (896%). The PUU dielectric enables the intrinsically stretchable, all-solution-processed organic transistor to operate at a low operational voltage down to -10 V, while preserving a substantial mobility of 1.39 cm2 V-1 s-1. Impressively, the transistor also demonstrates excellent electrical stability under repeated switching of 10 000 cycles, and remarkable mechanical robustness when stretched up to 100%. The work opens up a new molecular engineering strategy to successfully realize low-voltage high-mobility stretchable all-solution-processed organic transistors.