Preparation of pH‐stimuli‐responsive PEG–TGA/TGH‐capped CdTe QDs and their application in cell labeling

Facile production of smart superhydrophobic nanocomposite for wood coating towards long-lasting glow-in-the-dark photoluminescence

A smart photoluminescent nanocomposite surface coating was prepared for simple industrial production of long-persisting phosphorescence and superhydrophobic wood. The photoluminescent nanocomposite coatings were capable of continuing to emit light in the dark for prolonged time periods that could reach 1.5 h. Lanthanide-doped aluminium strontium oxide (LASO) nanoparticles at different ratios were immobilized in polystyrene (PS) and developed as a nanocomposite coating for wood substrates. To produce transparency in the prepared nanocomposite coating, LASO was efficiently dispersed in the form of nanoscaled particles to ensure homogeneous dispersion without agglomeration in the PS matrix. The coated wood showed an absorption band at 374 nm and two emission bands at 434 nm and 518 nm. The luminescence spectra showed both long-persisting phosphorescence as well as photochromic fluorescence relying on the LASO ratio. The improved superhydrophobicity and resistance to scratching of the coated wood could be attributed to the LASO NPs incorporated in the polystyrene matrix. Compared with the uncoated wood substrate, the coated LASO-PS nanocomposite film also displayed photostability and high durability. The current study demonstrated the potential high-scale manufacturing of smart wood for some applications such as safety directional signs in buildings, household products, and smart windows.

Plasmid DNA Mono-Ion Complex for in Vivo Sustainable Gene Expression

To cleave biocompatible poly(ethylene glycol) (PEG) from the mono-ion complex (MIC) for sustainable cellular uptake in vivo, ω-amide-pentylimidazolium end-modified PEG with an ester bond, that is, APe-Im-E-PEG, has been synthesized. The hydrolysis of the resulting APe-Im-E-PEG proceeded during the incubation for 2 weeks under physiological conditions, which was confirmed by gel filtration chromatography. APe-Im-E-PEG formed the MIC with plasmid DNA (pDNA), assessed by agarose gel retardation assay. Furthermore, dynamic light scattering measurement and transmission electron microscopy observations have estimated that the particle size of the resulting MIC was approximately 30 nm, with a rather flexible structure. The APe-Im-E-PEG/pDNA MIC incubated for 2 weeks exhibited hemolytic activity at endosomal pH, presumably because the pH-sensitive carboxyl groups revealed after the hydrolysis of an ester bond of APe-Im-E-PEG. The APe-Im-E-PEG/pDNA MIC enhanced the gene expression 2 weeks after transfection in vivo by intramuscular administration in mice. Consequently, in vivo sustainable gene expression has been achieved by the molecular design of APe-Im-E-PEG for cellular uptake and endosomal escape proceeded by temporal hydrolysis of the ester bond.

The effect of PEG functionalization on the in vivo behavior and toxicity of CdTe quantum dots

CdTe quantum dots (QDs) are considered a potential toxic substance because they contain metal ions. However, most toxicology data are derived from in vitro studies or limited in vivo analysis and may not reflect in vivo responses and biodistribution. Proper modification is one of the most widely used routes to reduce the toxicity of QDs. Herein, we demonstrated the role of polyethylene glycol (PEG) in decreasing the toxicity of QDs by studying the animal survival, clinical biochemistry, organ histology, biodistribution and oxidative stress in thioglycolic acid (TGA)- and mercapto-acetohydrazide (TGH)-stabilized CdTe QD (TGA/TGH-CdTe QD)-treated groups. Via the histology, transmission electron microscopy (TEM) and biodistribution results, it was found that the QDs mainly accumulated in the liver and kidney at 7 days post-injection, and obvious tissue damage was also observed in the bare TGA/TGH-CdTe QD group. Based on the evaluation of oxidative stress in the liver and kidney, the indicators exhibited an obvious variation with a high dose of TGA/TGH-CdTe QDs. In contrast, the QD aggregation decreased in the liver and kidney with no clear physiological index variation after PEG functionalization. Thus, PEG plays an important role in decreasing the toxicity of the CdTe QDs, and both the accumulation of cadmium and oxidative stress variation instead of an isolation factor are responsible for the in vivo toxicity of these QDs.

CdTe quantum dots (QDs) are considered a potential toxic substance because they contain metal ions.

Cleavable PEGylation: a strategy for overcoming the "PEG dilemma" in efficient drug delivery

To prolong the circulation time of drug, PEGylation has been widely used via the enhanced permeability and retention (EPR) effect, thereby providing new hope for better treatment. However, PEGylation also brings the "PEG dilemma", which is difficult for the cellular absorption of drugs and subsequent endosomal escape. As a result, the activity of drugs is inevitably lost after PEG modification. To achieve successful drug delivery for effective treatment, the crucial issue associated with the use of PEG-lipids, that is, “PEG dilemma” must be addressed. In this paper, we introduced the development and application of nanocarriers with cleavable PEGylation, and discussed various strategies for overcoming the PEG dilemma. Compared to the traditional ones, the vehicle systems with different environmental-sensitive PEG-lipids were discussed, which cleavage can be achieved in response to the intracellular as well as the tumor microenvironment. This smart cleavable PEGylation provides us an efficient strategy to overcome “PEG dilemma”, thereby may be a good candidate for the cancer treatment in future.

Preparation of core/shell CdTe@hMSN for enhanced tumor vasculature-specific drug delivery

Due to excellent optical properties, CdTe quantum dots (QDs) exhibit great potential in cancer imaging. However, CdTe QDs can be quickly cleared out before reaching the desired location because of their ultra-small size. The structure and optical properties of CdTe QDs are also easily affected by the surrounding solution, which leads to their compromised applications in vivo. Here, CdTe QDs were incorporated into hollow mesoporous silica nanoparticles (hMSN) to form CdTe@hMSN nano-platforms. The as-synthesized system maintained the excellent emission properties of CdTe QDs; meanwhile, relatively high drug loading efficiency was also observed for doxorubicin (DOX). With the target for vascular endothelial growth factor (VEGF), the formed CdTe@hMSN(DOX)–VEGF Abs showed feasibility of tumor-oriented drug delivery and CdTe@hMSN conjugate accumulation. The high accumulation and enhanced targeted drug delivery of CdTe@hMSN conjugates in tumor nodules confirmed that CdTe@hMSN conjugates can serve as promising candidates for cancer detection and treatment.

Due to excellent optical properties and high cargo holding capacity, CdTe@hMSN exhibit great potential in cancer imaging and drug delivery.