•A new amphiphilic bifunctional pullulan derivative (named as PDP) was prepared.•PDP exhibited good blood compatibility and low cytotoxicity.•PDP formed cationic core-shell nanomicelles, loading drugs and genes simultaneously.•PDP/DOX/p53 micelles exhibited higher antitumor efficacy in vitro and in vivo.•PDP holds great promise in combined drug/gene treatment for efficient cancer therapy.The greatest crux in the combination of chemotherapy and gene therapy is the construction of a feasible and biocompatible carrier for loading the therapeutic drug and gene simultaneously. Here, a new amphiphilic bifunctional pullulan derivative (named as PDP) synthesized by grafting lipophilic desoxycholic acid and low-molecular weight (1 kDa) branched polyethylenimine onto the backbone of pullulan was evaluated as a nano-carrier for the co-delivery of drug and gene for potential cancer therapy. PDP exhibited good blood compatibility and low cytotoxicity in the hemolysis and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, respectively. By self-assembly process, the amphiphilic PDP polymer formed cationic core-shell nanomicelles in aqueous solution with an average diameter of 160.8 nm and a zeta potential of approximate 28 mV. The PDP micelles had relative higher drug encapsulation efficiency (84.05%) and loading capacity (7.64%) for doxorubicin (DOX), an effective anti-tumor drug, demonstrating sustained drug release profile and good DNA-binding ability. The flow cytometry and confocal laser scanning microscopy showed that PDP/DOX micelles could be successfully internalized by MCF-7 cells, and presenting higher cytotoxicity against MCF-7 cells than that of free DOX. Furthermore, PDP micelles could efficiently transport tumor suppressor gene p53 into MCF-7 cells, and the expressed exogenous p53 protein induced MCF-7 cells to die. More excitedly, in comparison with single DOX or p53 delivery, the co-delivery of DOX and gene p53 using PDP micelles displayed higher cytotoxicity, induced higher apoptosis rate of tumor cells and blocked more effectively the migration of cancer cells in vitro. In tumor-bearing mice, co-delivery of DOX and p53 also exhibited enhanced antitumor efficacy as compared with single delivery of DOX or p53 alone. In summary, these results demonstrated that it is highly promising to use cationic PDP micelles for effectively co-delivering functional gene and chemotherapeutic agent, and thus improving antitumor efficacy and systemic toxicity.

Activatable photosensitizers that can be activated by cancer-associated stimuli have drawn increasing attention for simultaneous fluorescence imaging and photodynamic ablation of cancer cells. Here, we developed a cancer-cell specific photosensitizer nano-delivery system by synthesizing protoporphyrin IX (PpIX)-conjugated pullulan (P) with reducible disulfide bonds. The amphiphilic P-s-s-PpIX conjugate self-assembled in aqueous condition to form core-shell structured nanoparticles (P-s-s-PpIX NPs) with average size of 166 nm, showing reduction-controllable stability. In in vitro, the photoactivity of P-s-s-PpIX NPs in an aqueous environment was significantly suppressed by the self-quenching effect, which kept P-s-s-PpIX NPs in a photo-inactive and quenched state. But in the presence of GSH, P-s-s-PpIX NPs quickly dissociated by reductive breakage of disulfide linkers, followed by the significant recovery of fluorescent emission and singlet oxygen generation. In MCF-7 cells, compared to non-reducible P-PpIX NPs with stable amide linkages, P-s-s-PpIX NPs displayed higher cytotoxicity and induced higher apoptosis rate of tumor cells with light irradiation treatment. As a result, the P-s-s-PpIX NPs may serve as an effective smart nanomedicine platform for specific light-up and reduction-triggered cancer imaging and photodynamic therapy with the prominently reduced damage to normal tissues and cells.Download high-res image (118KB)Download full-size image

The first Golgi-localized cyclooxygenase-2 (COX-2)-specific near-infrared (NIR) fluorescent probe, Niblue-C6-IMC, able to detect cancer cells, was designed. Importantly, Niblue-C6-IMC preferentially labeled the tumors in a mouse tumor model with deep tissue penetration capacity. It may be a promising molecular tool for guiding tumor resection during surgery.

We report a highly selective and sensitive fluorescent probe (FP) for detecting fluoride ions, for the first time, lighting up the fluoride ions in mitochondria with a strong green fluorescence. FP could be easily prepared as fluoride paper test strips to detect fluoride ions in aqueous solutions with a detection limit as low as 19 ppb.

•Tocopheryl pullulan-based (PUTC) self-assembling nanomicelles were fabricated.•These micelles showed low CMC and dispersed uniformly with regular spherical shape.•High entrapment efficiency and in vitro sustained release of HCPT in PUTC micelles•HCPT–PUTC micelles accumulated in cell nuclei and showed higher anticancer activity.•Blank PUTC micelles were biocompatible and showed low cytotoxicity to normal cells.Amphiphilic α-tocopherol pullulan polymers (PUTC1, PUTC2, and PUTC3) with different degrees of substitution were synthesized as new carriers for anticancer drugs. The polymers easily self-assembled into nanomicelles through dialysis method. The critical micelle concentrations (CMCs) were 38.0, 8.0, and 4.3 mg/L for PUTC1, PUTC2, and PUTC3, respectively. 10-Hydroxycamptothecin (HCPT) used as a model drug was successfully loaded into the PUTC nanomicelles. Transmission electron microscopy images demonstrated that HCPT-loaded PUTC nanomicelles were almost spherical and had sizes ranging within 171.5–257.8 nm that increased with increased HCPT-loading content, as determined by dynamic laser scattering. The highest encapsulation efficiency of HCPT in PUTC nanomicelles reached 98.3%. The in vitro release of HCPT from PUTC micelles demonstrated sustained release for over 80 h. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assays showed that blank PUTC micelles were nontoxic to normal cells and that the HCPT-loaded PUTC2 nanomicelles showed higher cytotoxicity than the free drug, which was attributed to the enhanced cellular uptake of drug-loaded nanomicelles. Biodistribution experiments showed that PUTC micelles provided an excellent approach to rapid drug transport into cell nuclei. Moreover, the cellular uptake of micelles was found to be an energy-dependent and actin polymerization-associated endocytic process by endocytosis inhibition experiments. These results suggested that PUTC nanomicelles had considerable potential as a drug carrier for drug intracellular delivery in cancer therapy.

•New gene delivery vector, folate–PEI–modified pullulan (P–PEI–FA), was synthesized.•It can efficiently wrap pDNA/siRNA at optimal N/P, help pDNA against degradation.•P–PEI–FA/pDNA showed lower cytotoxicity, displayed high gene transfection efficiency.•P–PEI–FA/siRNA at N/P ratio of 12.5 demonstrated enhanced gene silencing effect.•P–PEI–FA can assist DNA or siRNA targeting to FR-overexpressing cells.Folate receptor (FR)-mediated gene/short interfering RNA (siRNA) targeting shows advantage for the delivery of gene/siRNA into specific FR-overexpressing cancer cells. In this study, the non-targeted gene vector P–PEI was synthesized by grafting low-molecular-weight (1 kDa) branched polyethyleneimine (PEI) to succinylated pullulan, and the targeted gene vector P–PEI–FA was synthesized by coupling the carboxyl of folate (FA) to the amino of PEI. Gel electrophoresis retardation assay demonstrated that both P–PEI and P–PEI–FA can efficiently wrap pDNA and siRNA with electrostatic interaction at N/P ratios higher than 1.56 and can protect pDNA from degradation by DNase I and serum. Compared with PEI/pDNA, P–PEI/pDNA and P–PEI–FA/pDNA showed lower cytotoxicity against different cells. Under serum-containing conditions, compared with Lipofamine 2000/DNA and Lipofamine2000/siRNA, P–PEI–FA/DNA at N/P ratio of 6.25 displayed higher gene transfection efficiency, whereas P–PEI–FA/siRNA at N/P ratio of 12.5 demonstrated better enhanced gene silencing effect. P–PEI–FA/siRNA can also deliver FAM-labeled siRNA to endosomes and escape. Moreover, the gene transfection and silencing effects of P–PEI–FA were higher than those of P–PEI, and were dependent on the dose of FA in FR+ HeLa cells. Thus, P–PEI-FA can assist DNA or siRNA targeting to FR-overexpressing cells, and the uptake pathway of P–PEI–FA/siRNA was FR-mediated endocytosis. These results indicate that P–PEI–FA is a potential candidate for safe and targeted gene delivery applications.

The first Golgi-localized cyclooxygenase-2 (COX-2)-specific near-infrared (NIR) fluorescent probe, Niblue-C6-IMC, able to detect cancer cells, was designed. Importantly, Niblue-C6-IMC preferentially labeled the tumors in a mouse tumor model with deep tissue penetration capacity. It may be a promising molecular tool for guiding tumor resection during surgery.

We report a highly selective and sensitive fluorescent probe (FP) for detecting fluoride ions, for the first time, lighting up the fluoride ions in mitochondria with a strong green fluorescence. FP could be easily prepared as fluoride paper test strips to detect fluoride ions in aqueous solutions with a detection limit as low as 19 ppb.