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The development of intelligent drug delivery system that can efficiently deliver drug to targeted site and release the cargo in a controlled manner is of great significance for cancer chemotherapy. In the present study, dual redox/pH-sensitive amphiphilic copolymer, cholesterol modified poly (β-amino esters)-grafted disulfide poly (ethylene glycol) methyl ether (PAE(-ss-mPEG)-g-Chol), is successfully synthesized via Michael-type step polymerization using disulfide linkage-containing PEG segment. PEGylated lipid is introduced to fabricate the doxorubicin (DOX)-loaded hybrid polymer-lipid nanoparticles (NPs) with (DOX-HDPLNPs) or without (DOX-HPLNPs) disulfides to receive stable NPs with enhanced loading capacity and improved cellular uptake ability as well as serum stability. The HDPLNPs show not only pH-sensitivity because of poly(β-amino esters) (PAE) residues in main chain but also the redox-responsivity due to the disulfides on the side chains with PEG segments. As expected, the DOX-HDPLNPs exhibited the extended blood circulation time and higher serum stability in normal physiological environment, but once deposited in the tumor microenvironment (e.g. low pH value and high GSH concentration), they underwent a dramatic size transition and charge reversal. These features not only can facilitate the NPs accumulation through the enhanced permeability and retention (EPR) effect and endocytosis by tumor cells but also realize the drug controlled release and more efficient tumor inhibition. The in vitro and in vivo results demonstrate that the DOX-HDPLNPs possess the highest therapeutic efficacy with high cellular uptake and negligible cytotoxicity compared to the controls and free drug. Therefore, the HDPLNPs have good potential as smart delivery platforms for hydrophobic anticancer drug delivery due to high uptake by tumor cells and redox/pH-triggered drug release.

Self-assembly of the corresponding europium and terbium salts with designed chiral ligand (S)-5-((2-carboxy-5-oxopyrrolidin-1-yl)methyl)isophthalic acid (H3L) generated two novel 3D coordination polymers {[Eu(L)]·0.5CH3CN}n (1) and {[Tb(L)]·0.5CH3CN}n (2). Single-crystal X-ray diffraction analyses reveal that 1 and 2 are isostructural metal-organic frameworks built from four-stranded helixes. Complexes 1 and 2 are intriguing homochiral porous architectures with 6,6-connected (48∙66∙8)(413∙62) topology, whose homochirality was further confirmed by their solid-state circular dichroism spectra. Thermal analyses disclose that the desolvated frameworks of 1 and 2 can maintain their structural stability below 370 ​°C. Solid-state photoluminescence studies show that 1 and 2 exhibit strong characteristic Eu(III) and Tb(III) emissions with long lifetimes of 1.31 and 1.35 ​ms, respectively. In addition, 1 and 2 also exhibit significant second harmonic generation activities with their intensities of about 0.29 and 0.31 times larger than that of potassium dihydrogenphosphate, respectively. Very importantly, the excellent thermostabilities and strong red and green emissions of 1 and 2 are of great significance for further exploration of their applications in optical devices.

Utilizing chiral terpyridine derivative ligand (S)-2-((4-([2,2′:6′,2″-terpyridin]-4′-yl)benzyl)amino)propanoic acid (HL) and corresponding Ln(NO3)3, five new isostructural homochiral lanthanide metal–organic frameworks [{[Ln2(HL)2(NO3)4(H2O)4]·NO3·Cl·7H2O}n [Ln = Nd (1), Pr (2), Sm (3), Eu (4), Tb (5)] comprised of left- and right-handed helical chains were solvothermally synthesized. Various means such as IR spectroscopy, elemental analysis, powder X-ray diffraction, and thermal analysis were used to characterize the compounds, wherein compounds 1 and 2 were crystallographically characterized. In the structure of representative 1, zwitterionic ligands HL bridge Nd3+ ions through the monodentate coordination of their carboxylates and the tridentate chelation of their terpyridyls, leading to the formation of left- and right-handed helical chains. The adjacent left- and right-handed helical chains are further connected into a 2D helical layer through interchain hydrogen-bonding interactions, and these layers stack up through interlayer π⋯π interactions to form an interesting three-dimensional homochiral cationic architecture with one-dimensional triangular channels wherein guests anions and water are trapped. The compounds were systematically studied with respect to their solid-state optical properties, including CD spectra, and nonlinear optical and luminescent properties, and the results showed that the sensitization effect of HL ligand on the emission of Tb3+ and Eu3+ was better than that of Sm3+.