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Objective: To construct a nanodelivery system surface-modified with RD2 peptide (polypeptide sequence PTLHTHNRRRRR) for brain tissue penetration and β-amyloid (Aβ) binding. Epigallocatechin-3-gallate (EGCG) was selected for encapsulation in the targeted delivery system and its therapeutic potential for Alzheimer's disease (AD) was investigated., Methods: EGCG-load nanoparticles (NP/EGCG), NP/EGCG with RD2 peptide surface modification (RD2-NP/EGCG), as well as RD2 peptide-modified blank nanoparticles (RD2-NP) were prepared and characterized. Thioflavin T assay was done to assess the ability of RD2-NP to bind with Aβ and ex vivo imaging was conducted to evaluate the distribution of RD2-NP in brain lesion sites. The AD mice model was established by injecting oligomeric Aβ 42 in the bilateral hippocampi of ICR mice. Then AD mice were administered intravenously through the tail vein with normal saline, EGCG solution, NP/EGCG or RD2-NP/EGCG for 28 d, respectively, and the Morris water maze tests were performed to assess the spatial memory of mice. Subsequently, RT-PCR method was used to determine the mRNA levels of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in the hippocampus of the mice, and the morphological changes of hippocampal neurons were observed with Nissl staining. Additionally, the pathological changes of heart, liver, spleen, lung, and kidney were characterized by hematoxylin-eosin (HE) staining., Results: The particle diameter of the prepared RD2-NP/EGCG was (204.83±2.80) nm and the zeta potential was -23.88 mV. The encapsulation efficiency and drug loading capacity were 94.39% and 5.90%, respectively. The RD2 peptide modification has no significant effect on the physiochemical properties of the nanoparticles. RD2-NP had good Aβ binding ability, and it could be concentrated in hippocampus and cerebral cortex, the most common Aβ deposition sites. The four-week RD2-NP/EGCG treatment significantly decreased the expression of the pro-inflammatory cytokine TNF-α and IL-1β, restored neuronal losses and hippocampal damage, and ameliorated spatial memory impairment in AD model mice. Moreover, treatment with the RD2-NP/EGCG did not present organ toxicity., Conclusion: Surface modified RD2 peptide nanodelivery system can efficiently deliver drugs to AD lesions and improve the therapeutic effect of EGCG on AD., (Copyright© by Editorial Board of Journal of Sichuan University (Medical Sciences).)

Background: Characterization of early breast cancer circulating tumor cells (CTCs) may provide valuable information on tumor metastasis. Methods: We used immunomagnetic nanospheres to capture CTCs from the peripheral blood of eight early breast cancer patients and then performed single‐cell RNA sequencing using our proposed bead‐dd‐seq method. Results: CTCs displayed obvious tumor cell characteristics, such as the activation of oxidative stress, proliferation, and promotion of metastasis. CTCs were clustered into two subtypes significantly correlated with the lymph node metastasis status of patients. CTCs in subtype 1 showed a strong metastatic ability because these CTCs have the phenotype of partial epithelial‐mesenchymal transition and enriched transcripts, indicating breast cancer responsiveness and proliferation. Furthermore, DNA damage repair pathways were significantly upregulated in subtype 1. We performed in vitro and in vivo investigations, and found that cellular oxidative stress and further DNA damage existed in CTCs. The activated DNA damage repair pathway in CTCs favors resistance to cisplatin. A checkpoint kinase 1 inhibitor sensitized CTCs to cisplatin in mouse models of breast cancer metastasis. Conclusion: The present study dissects the molecular characteristics of CTCs from early‐stage breast cancer, providing novel insight into the understanding of CTC behavior in breast cancer metastasis. [ABSTRACT FROM AUTHOR]

SiO2 encapsulated quantum dots (QDs@SiO2) have been widely adopted for fabricating high-performance phosphor-converted light-emitting diodes (QCLEDs). However, the impact of SiO2 thickness on the optical properties of QDs in QCLEDs remains largely unexplored. In this work, we studied the combined effects of light scattering, heat accumulation, and concentration quenching of QD@SiO2 on optical performance of QCLEDs. QDs@SiO2 nanoparticles with SiO2 thickness of 10–60 nm were developed to perform the experimental tests and optical and thermal simulations. Our study reveals that at low power density, QD@SiO2 with 20–30-nm SiO2 shell display optimal efficiency owning to suppressed self-absorption quenching and enhanced light scattering. However, because of heat accumulation inside QDs@SiO2 at high power density, thin SiO2 shell (10–15 nm) is more favorable to reduce thermal quenching and maintain luminous efficiency of QCLEDs. This study provides guidance for the development of appropriate QDs@SiO2 structure to meet application requirements of different QCLED devices. [ABSTRACT FROM AUTHOR]

Abstract: Up-conversion nanoparticles (UCNPs), which can convert a longer wavelength radiation to a shorter wavelength radiation, have great potential use as bio-labels in biological detection. However, these NPs usually cannot be used directly unless their surface is further modified. Herein, we developed a novel and straightforward method for the synthesis of monodisperse NaYF4:Yb,Er/Polymer UCNPs. The resultant UCNPs exhibited a pure hexagonal phase, strong UC fluorescent intensity, and a uniform size of about 40nm, which were characterized by XRD, luminescence spectroscopy and TEM, respectively. FT-IR spectra revealed that these NPs were coated with a layer of hydrophilic polymers (including PVP, PEG, PAA and PEI), thus the NPs could be dispersed in water easily. More importantly, the PAA and PEI coated NPs were functionalized by –COOH and –NH2 groups, respectively, which were expected to be used for further bio-conjugation. [Copyright &y& Elsevier]