Poly(ε-caprolactone) modified organic dyes nanoparticles for noninvasive long term fluorescence imaging

Advances in organocatalyzed synthesis of organic compounds

The recent advancements in utilizing organocatalysts for the synthesis of organic compounds have been described in this review by focusing on their simplicity, effectiveness, reproducibility, and high selectivity which lead to excellent product yields. The organocatalytic methods for various derivatives, such as indoles, pyrazolones, anthrone-functionalized benzylic amines, maleimide, polyester, phthalimides, dihydropyrimidin, heteroaryls, N-aryl benzimidazoles, stilbenoids, quinazolines, quinolines, and oxazolidinones have been specifically focused. The review provides more understanding by delving into potential reaction mechanisms. We anticipate that this collection of data and findings on successful synthesis of diverse compound derivatives will serve as valuable resources and stimulating current and future research efforts in organocatalysis and industrial chemistry.

Surface state dominated and carbon core coordinated red-emitting carbon dots for the detection of Cr2O72- and cell imaging

Cr(VI) as a toxic heavy metal ion can easily enter into the body through drinking or eating and cause liver and kidney diseases as well as cancer. Considering its high biological toxicity and adverse effects on human body, it is desirable to develop a probe to monitor its level in the environment. Herein, a high-efficiency fluorescent nanoprobe based on red emissive carbon dots (R-CDs) was established through a convenient solvothermal strategy. The as-prepared CDs with excitation-independency had the fixed emission wavelength at 627 nm when the excitation wavelength was 560 nm. Further study manifested that the new surface state formed by nitrogen and sulfur doping and the increased conjugated system established through dehydration and carbonization were the main reasons for the fluorescence redshift. In this system, these R-CDs as a fluorescent probe exhibited high specificity and sensitivity to Cr₂O₇^2- with the linear range of 4-40 μΜ and the limit of detection could reach 80.00 nM. The quenching of these CDs by Cr₂O₇^2- was efficiently induced through a static quenching process. Meanwhile, the obtained CDs could enter into HeLa cells through endocytosis and exhibit bright red fluorescence in cells under a confocal laser scanning microscope. Thus, this work provided a promising probe not only for detecting Cr(VI) in natural environment but also for imaging in cells.

A universal strategy for the fabrication of single-photon and multiphoton NIR nanoparticles by loading organic dyes into water-soluble polymer nanosponges

The development of optical organic nanoparticles (NPs) is desirable and widely studied. However, most organic dyes are water-insoluble such that the derivatization and modification of these dyes are difficult. Herein, we demonstrated a simple platform for the fabrication of organic NPs designed with emissive properties by loading ten different organic dyes (molar masses of 479.1–1081.7 g/mol) into water-soluble polymer nanosponges composed of poly(styrene-alt-maleic acid) (PSMA). The result showed a substantial improvement over the loading of commercial dyes (3.7–50% loading) while preventing their spontaneous aggregation in aqueous solutions. This packaging strategy includes our newly synthesized organic dyes (> 85% loading) designed for OPVs (242), DSSCs (YI-1, YI-3, YI-8), and OLEDs (ADF-1–3, and DTDPTID) applications. These low-cytotoxicity organic NPs exhibited tunable fluorescence from visible to near-infrared (NIR) emission for cellular imaging and biological tracking in vivo. Moreover, PSMA NPs loaded with designed NIR-dyes were fabricated, and photodynamic therapy with these dye-loaded PSMA NPs for the photolysis of cancer cells was achieved when coupled with 808 nm laser excitation. Indeed, our work demonstrates a facile approach for increasing the biocompatibility and stability of organic dyes by loading them into water-soluble polymer-based carriers, providing a new perspective of organic optoelectronic materials in biomedical theranostic applications.

CdTe@CdS quantum dots for labeling and imaging of macrophages in liver frozen section below freezing point

CdTe@CdS core-shell quantum dots with different particle sizes are synthesized by aqueous method, and the coating of CdS shell layer improves the quantum yield (36%→59%) and fluorescence stability (37%→77%) of...

Generating circularly polarized luminescence from clusterization-triggered emission using solid phase molecular self-assembly

Purely-organic clusterization-triggered emission (CTE) has displayed promising abilities in bioimaging, chemical sensing, and multicolor luminescence. However, it remains absent in the field of circularly polarized luminescence (CPL) due to the difficulties in well-aligning the nonconventional luminogens. We report a case of CPL generated with CTE using the solid phase molecular self-assembly (SPMSA) of poly-L-lysine (PLL) and oleate ion (OL), that is, the macroscopic CPL supramolecular film self-assembled by the electrostatic complex of PLL/OL under mechanical pressure. Well-defined interface charge distribution, given by lamellar mesophases of OL ions, forces the PLL chains to fold regularly as a requirement of optimal electrostatic interactions. Further facilitated by hydrogen bonding, the through-space conjugation (TSC) of orderly aligned electron-rich O and N atoms leads to CTE-based CPL, which is capable of transferring energy to an acceptor via a Förster resonance energy transfer (FRET) process, making it possible to develop environmentally friendly and economic CPL from sustainable and renewable materials.

A quinacridone derivative with intensive emission in both solution and the solid state via a facile preparation for cell imaging applications

tert-Butyloxycarbonyl (TBOC) substituted quinacridone (QA) derivative TBOC-QA was synthesized via a one-step simple chemical reaction and showed intense emission in both solution and the solid state.

Robust organic nanoparticles for noninvasive long-term fluorescence imaging

Organic nanoparticles obtained from fluorophores with aggregation-caused quenching and aggregation-induced emission features for noninvasive long-term bioimaging are summarized and highlighted.