Biomineralization of a rare earth ion (Gd) is first employed to assemble bovine serum albumin (BSA) into sub-50 nm nanoparticles (Gd@BSA) for theranostic applications, via a straightforward and reproducible strategy. Combination of Gd ions with BSA under mild conditions results in the formation of the Gd@BSA nanosystem, which has been used as the scaffold material to encapsulate a photosensitiser (Ce6) with high efficiency up to 20 wt%. Beyond playing an important role in the assembled process, the incorporation of Gd affords the potential MRI and fluorescence imaging capability of Gd@BSA-Ce6 nanoparticles. In vivo MRI allowed real-time imaging in tumor-bearing mice and showed advantages in terms of circulation time, compared with commercially used Gd–DTPA. Gd@BSA-Ce6 nanoparticles exhibited enhanced tumor-specific distribution, through enhanced permeability and retention effect, and complete cure of tumor-bearing mice after intravenous injection. The nanoparticles did not produce systemic toxicity as revealed by biodistribution and histology toxicity analyses. The results demonstrate the great potential of Gd@BSA-Ce6 nanoparticles as theranostic agents due to their excellent imaging and tumor-growth-inhibition properties.

Dendrimer catiomers like dendrigraft poly-L-lysine (DGL) have been very popular vectors for gene delivery recently; however, they generally suffer from serious cytotoxicity for high density of positive charge. PEGylated DGL engineered using the PEG cleavable mechanism (DGL(R)-SS-mPEG) was first developed as a non-viral gene vector for cancer intervention. Cleavable PEGylation of the DGL catiomer in tumor relevant glutathione (GSH) conditions enables us to dramatically decrease the cytotoxicity as well as to promote the intracellular release and expression of the genetic payload. Like DGL, DGL(R)-SS-mPEG is capable of efficiently complexing with plasmid DNA (pDNA) to afford homogeneous compact nano-complexes. Those gene carrying nanostructures could be stably dispersed in the regular serum medium without GSH, but with fast PEG dis-assembly if subject to 10 mM GSH. Compared with the non-cleavable counterpart, PEG-cleavable dendrigraft poly-L-lysine exhibited significantly higher enhanced green fluorescence protein (EGFP) expression against 293T cells. By using small interfering RNA (siRNA-VEGF) as the therapeutic gene payload, the complex nanoparticles demonstrated the pronounced inhibition effect on cell growth in vitro and tumor growth in vivo. The promising results revealed a universal strategy to balance disadvantages and advantages of dendrimer catiomers for future non-viral gene delivery vector.

Supramolecular polymer micelles (SMPMs) engineered by the host–guest interaction of α-cyclodextrin (α-CD) and poly(ε-capralactone) (PCL) homopolymer have been recently reported as robust drug delivery systems. The incorporation of supramolecular chemistry affords significantly obvious advantages of convenience in fabrication and controllability in properties, in contrast to conventional micelles. This work aims to design and develop novel SMPMs assembled by the anticancer drug camptothecin carrying PCL (CPT-PCL) and α-CD. The prodrug strategy developed not only can introduce the steric effect to facilitate the supramolecular nano-assembly but also can provide the capability to prevent the premature release as well as to regulate the drug release by enzymes. The CPT drug and PCL polymer were chemically bonded through an ester bond linkage hydrolyzable in the presence of lipase. The resultant SMPMs were spherical with a hydrodynamic size of around 220 nm and a fixed drug ratio dependent on the molecular weight of PCL employed. The enzyme-induced drug release behavior and cytotoxicity of CPT-carrying SMPMs were further evaluated, and the results revealed the promising application of these micelles for controlled drug delivery.

Presented in this article is the preparation of a new theranostic vesicle which exhibits excellent in vitro and in vivo T1 magnetic resonance (MR) imaging contrast effect and good anticancer drug delivery ability. The theranostic vesicle has been easily prepared based on an amphiphilic biocompatible and biodegradable dibock copolymer, poly(ethylene glycol)-block-poly(l-lactic-co-glycolic acid) (PEG-b-PLGA) and bovine serum albumin-gadolinium (BSA-Gd) complexes. Dynamic light scattering (DLS), transmission electron microscopy (TEM), UV–vis spectroscopy, and inductively coupled plasma atomic emission spectroscopy (ICP-AES) measurements confirmed the formation and physiological stability of BSA-Gd@PEG-b-PLGA vesicles. Furthermore, the in vitro and in vivo MR imaging experiments revealed their excellent T1-weighted MR imaging function. Red blood cell hemolysis and cytotoxicity experiments confirmed their good blood compatibility and low cytotoxicity. Doxorubicin (DOX) loading and release experiments indicated a more retarded release rate of DOX in those theranostic vesicles than sole PEG-b-PLGA nanoparticles without BSA. Overall, this new biocompatible and biodegradable vesicle shows promising potential in theranostic applications.

PKKKRKV (Pro-Lys-Lys-Lys-Arg-Lys-Val, PV7), a seven amino acid peptide, has emerged as one of the primary nuclear localization signals that can be targeted into cell nucleus via the nuclear import machinery. Taking advantage of chemical diversity and biological activities of this short peptide sequence, in this study, Pluronic F127 nanomicelles engineered with nuclear localized functionality were successfully developed for intracellular drug delivery. These nanomicelles with the size ~ 100 nm were self-assembled from F127 polymer that was flanked with two PV7 sequences at its both terminal ends. Hydrophobic anticancer drug doxorubicin (DOX) with inherent fluorescence was chosen as the model drug, which was found to be efficiently encapsulated into nanomicelles with the encapsulation efficiency at 72.68%. In comparison with the non-functionalized namomicelles, the microscopic observation reveals that PV7 functionalized nanomicelles display a higher cellular uptake, especially into the nucleus of HepG2 cells, due to the nuclear localization signal effects. Both cytotoxicity and apoptosis studies show that the DOX-loaded nanomicelles were more potent than drug nanomicelles without nuclear targeting functionality. It was thus concluded that PV7 functionalized nanomicelles could be a potentially alternative vehicle for nuclear targeting drug delivery.Highlights► A new nuclear targeted drug delivery system based on micelles is developed. ► This micellar system features a core-shell structure with the size peaked at 100 nm. ► PV7, a short peptide sequence, is adopted as a nuclear targeting ligand. ► PV7 functionalized drug loaded micelles are more potent in killing tumor cells.

Engineered PEG-detachable catiomers were developed as non-viral gene vectors to detach the PEG layers responsive to the intracellular reducing environment. These catiomers were found to exhibit high DNA binding ability and reduced cytotoxicity, as evidenced in agarose gel electrophoresis and MTT assays. The size of the mPEG-SS-PLL/DNA complexes was around 100 nm with a regular spherical shape, as observed under transmission electron microscopy (TEM). The complexes were stably dispersed in an aqueous medium with 10% serum. However, fast aggregation was observed in the presence of 10 mM glutathione (GSH) due to detachment of the PEG segment via disulfide cleavage. These complexes showed high transfection efficiency in 293T and Hela cells under optimized conditions. The experimental results indicated that the mPEG-SS-PLL catiomers may have promising potential as a non-viral gene vector.

Engineered PEG-detachable catiomers were developed as non-viral gene vectors to detach the PEG layers responsive to the intracellular reducing environment. These catiomers were found to exhibit high DNA binding ability and reduced cytotoxicity, as evidenced in agarose gel electrophoresis and MTT assays. The size of the mPEG-SS-PLL/DNA complexes was around 100 nm with a regular spherical shape, as observed under transmission electron microscopy (TEM). The complexes were stably dispersed in an aqueous medium with 10% serum. However, fast aggregation was observed in the presence of 10 mM glutathione (GSH) due to detachment of the PEG segment via disulfide cleavage. These complexes showed high transfection efficiency in 293T and Hela cells under optimized conditions. The experimental results indicated that the mPEG-SS-PLL catiomers may have promising potential as a non-viral gene vector.

Biomineralization of a rare earth ion (Gd) is first employed to assemble bovine serum albumin (BSA) into sub-50 nm nanoparticles (Gd@BSA) for theranostic applications, via a straightforward and reproducible strategy. Combination of Gd ions with BSA under mild conditions results in the formation of the Gd@BSA nanosystem, which has been used as the scaffold material to encapsulate a photosensitiser (Ce6) with high efficiency up to 20 wt%. Beyond playing an important role in the assembled process, the incorporation of Gd affords the potential MRI and fluorescence imaging capability of Gd@BSA-Ce6 nanoparticles. In vivo MRI allowed real-time imaging in tumor-bearing mice and showed advantages in terms of circulation time, compared with commercially used Gd–DTPA. Gd@BSA-Ce6 nanoparticles exhibited enhanced tumor-specific distribution, through enhanced permeability and retention effect, and complete cure of tumor-bearing mice after intravenous injection. The nanoparticles did not produce systemic toxicity as revealed by biodistribution and histology toxicity analyses. The results demonstrate the great potential of Gd@BSA-Ce6 nanoparticles as theranostic agents due to their excellent imaging and tumor-growth-inhibition properties.

Intelligent nanoparticles are capable of prolonged blood circulation without leakage of the payload and fast drug release upon exposure to environmental stimuli, such as redox stimuli, and therefore are highly desirable for cancer therapy. In this study, polymeric micelles were designed and developed with a hydrophilic poly(ethylene glycol) (PEG) shell and a hydrophobic poly-L-phenylalanine (PPhe) core, linked by a redox cleavable bond, i.e. mPEG-SS-PPhe. The mPEG-SS-PPhe micelles were loaded with the anticancer drug doxorubicin (DOX) and shown an on-demand release profile in the presence of redox agents such as glutathione (GSH). Remarkably, the GSH-triggered micellar dissociation accelerated in vitro release of DOX 4.87 fold faster at 10 mM GSH than that without GSH at 12 h. An enhanced inhibitory effect of DOX-loaded mPEG-SS-PPhe micelles was achieved by improving the intracellular GSH levels. Confocal laser scanning microscopy and flow cytometric analyses of HeLa cells further confirmed that DOX accumulation was accelerated by elevating the extracellular GSH concentrations. In addition, mPEG-SS-PPhe micelles showed excellent biocompatibility on L929 and HeLa cell lines. These redox-sensitive polymeric micelles may provide more possibilities as promising carriers for on-demand drug release in a controlled manner.

Dendrimer catiomers like dendrigraft poly-L-lysine (DGL) have been very popular vectors for gene delivery recently; however, they generally suffer from serious cytotoxicity for high density of positive charge. PEGylated DGL engineered using the PEG cleavable mechanism (DGL(R)-SS-mPEG) was first developed as a non-viral gene vector for cancer intervention. Cleavable PEGylation of the DGL catiomer in tumor relevant glutathione (GSH) conditions enables us to dramatically decrease the cytotoxicity as well as to promote the intracellular release and expression of the genetic payload. Like DGL, DGL(R)-SS-mPEG is capable of efficiently complexing with plasmid DNA (pDNA) to afford homogeneous compact nano-complexes. Those gene carrying nanostructures could be stably dispersed in the regular serum medium without GSH, but with fast PEG dis-assembly if subject to 10 mM GSH. Compared with the non-cleavable counterpart, PEG-cleavable dendrigraft poly-L-lysine exhibited significantly higher enhanced green fluorescence protein (EGFP) expression against 293T cells. By using small interfering RNA (siRNA-VEGF) as the therapeutic gene payload, the complex nanoparticles demonstrated the pronounced inhibition effect on cell growth in vitro and tumor growth in vivo. The promising results revealed a universal strategy to balance disadvantages and advantages of dendrimer catiomers for future non-viral gene delivery vector.