An acid-triggered BODIPY-based photosensitizer for enhanced photodynamic antibacterial efficacy.

Photodynamic inactivation of bacteria has emerged as a promising antibacterial strategy due to its high antibacterial activity and low bacterial resistance. Herein, an acid-triggered photodynamic antibacterial nanoplatform (IBPAAs) was constructed by co-assembly of an acid-triggered photosensitizer BODIPY (I-NBDP) and the POEGMA-b-PDEAEMA block copolymer for enhancing the antibacterial efficacy and biofilm-dissipation capability. IBPAAs could have great biocompatibility and stability by the formation of self-assemblies, and it could be cleaved to release the I-NBDP photosensitizer under a dual-step acidic response due to the protonation of the diethylamino groups on both I-NBDP and the POEGMA-b-PDEAEMA block copolymer. On the one hand, the photoinduced electron transfer (PET) of I-NBDP in IBPAAs under neutral conditions could be attenuated, resulting in an increase of its 1O2 yield, effectively improving its photodynamic antibacterial efficacy. On the other hand, the protonation of IBPAAs made it easier to target negatively charged bacterial surfaces, further enhancing its photodynamic antibacterial activity. The antibacterial experiments in vitro showed that the IBPAAs assemblies had great photodynamic antibacterial efficacy and biofilm dissipation capability, and it could effectively relieve bacterial infection of wounds and accelerate wound healing in vivo. Therefore, this acid-triggered strategy is expected to provide a new path for enhanced photodynamic antibacterial therapy.

Synergistic effect of the anti-PD-1 antibody with blood stable and reduction sensitive curcumin micelles on colon cancer.

Curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) is a potent anticancer drug with versatile biological activities, while the clinical translation of curcumin is severely limited due to its hydrophobicity, rapid elimination, and metabolism in the blood circulation. Herein, we aim to unravel the potential of curcumin as a synergistic agent with immunotherapy in the treatment of cancers. In an effort to minimize premature release and improve the systemic bioavailability, a superior blood stable and reduction sensitive curcumin micellar formulation, of which the release can be triggered by cancer cells, is rationally designed. We have synthesized a telodendrimer (mPEG-PLA-(LA)4) capable of forming reversible disulfide crosslinked micelles (DCMs). The curcumin loaded DCMs (Cur/DCMs) are spherical with a uniform size of 24.6 nm. The in vitro release profile demonstrates that curcumin releases significantly slower from DCMs than that from non-crosslinked micelles (NCMs), while the release can be accelerated with the increasing concentration of reducing agent glutathione (GSH). Intravenous administration of Cur/DCMs stably retains curcumin in the bloodstream and efficiently improves the systemic bioavailability. Furthermore, Cur/DCMs exhibit synergistic anticancer efficacy when combined with the anti-PD-1 antibody in an MC-38 colon cancer xenograft model. Our results potentiate the integration of blood stable curcumin nanoformulation and immunotherapy for cancer treatment.

Drug-interactive mPEG-b-PLA-Phe(Boc) micelles enhance the tolerance and anti-tumor efficacy of docetaxel.

Docetaxel (DTX) is one of the most promising chemotherapeutic agents for a variety of solid tumors. However, the clinical efficacy of the marketed formulation, Taxotere®, is limited due to its poor aqueous solubility, side effects caused by the emulsifier, and low selective DTX distribution in vivo. Here a facile, well-defined, and easy-to-scale up DTX-loaded N-(tert-butoxycarbonyl)-L-phenylalanine end-capped methoxy-poly(ethylene glycol)-block-poly(D,L-lactide) (mPEG-b-PLA-Phe(Boc)) micelles (DTX-PMs) were prepared in an effort to develop a less toxic and more efficacious docetaxel formulation. The physicochemical properties, pharmacokinetics, biodistribution, and in vivo anti-tumor efficacy were evaluated in comparison to the marketed DTX formulation Taxotere®. DTX was successfully encapsulated in the hydrophobic micellar core with a high encapsulation efficiency (> 95%) and a high drug loading capacity (4.81 ± 0.08%). DTX-PMs exhibited outstanding stability in the aqueous environment due to the strong interactions between the terminal amino acid residues and docetaxel. The pharmacokinetic study in Sprague-Dawley rats revealed higher DTX concentrations in both whole blood and plasma for the group treated with DTX-PMs than that treated with Taxotere® due to the improved stability of the micellar formulation. In human non-small cell lung cancer (A549) tumor-bearing Balb/c nude mice, DTX-PMs significantly improved DTX accumulation and stalled DTX elimination in tumors than in bone marrow. Furthermore, only by half of the DTX dosage, our DTX/mPEG-b-PLA-Phe(Boc) micelles can achieve similar therapeutic effects as Taxotere®. Altogether, DTX-PMs hold great promise as a simple and effective drug delivery system for cancer chemotherapy.

Cancer-targeted and glutathione-responsive micellar carriers for controlled delivery of cabazitaxel.

Novel type of multifunctional polymeric micelles (PMs) designated as HM-PMss/CTX micelles were developed in the present study for tumor-targeted and glutathione (GSH)-responsive delivery of cabazitaxel (CTX). The surface of the vehicles was modified with piloting molecules (HM-3 peptide), which targets α v ß 3 integrin overexpressed on cancer cells, and the micelle core was cross-linked by GSH-disintegrable disulfide linkages for controlled drug release. HM-PMss/CTX micelles were prepared using a mixture of two functionalized amphiphilic block copolymers and found to physically encapsulate CTX with excellent entrapment efficiency (93.94 ± 4.19%), drug-loading capacity (8.39 ± 2.28%), and a narrow size distribution. In vitro release profiles showed that CTX remained stably entrapped in the micelles in a release medium without GSH or with GSH of low concentration, while undergoing a rapid release in a highly reductive environment. Cellular uptake experiments showed that the conjugation of the targeting peptide, containing an arginine-glycine-aspartate sequence, enhanced the cellular uptake of HM-PMss/CTX micelles via α v ß 3 integrin-mediated endocytosis. In vitro cell viability measurements revealed that blank micelles were biocompatible, while HM-PMss/CTX micelles, owing to their tumor-targeting ability and GSH sensitivity, effectively inhibited the proliferation of MDA-MB-231 breast cancer cells. These results indicate that HM-PMss/CTX micelles could be a promising platform for future intelligent drug delivery in cancer therapy.

Synthesis, characterization, and in vitro evaluation of TRAIL-modified, cabazitaxel -loaded polymeric micelles for achieving synergistic anticancer therapy.

Combination therapy of two or more drugs has gradually become of outmost importance in cancer treatment. Cabazitaxel (CTX) is a taxoid drug and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of TNF superfamily. In this study, we prepared TRAIL-modified and CTX-loaded polymer micelle (TRAIL-M-CTX). This nanoparticle was self-assembled from biodegradable amphiphilic copolymers, monomethoxyl poly(ethylene glycol)-b-poly(DL-lactide) (mPEG-PLA) and COOH-PEG-PLA, via a nanoprecipitation method and were modified with the TRAIL protein, resulting in a particle size of 39.75 ± 0.17 nm in diameter and a drug encapsulation efficiency of 95.52 ± 1.69%. The successful coupling was confirmed by 1H NMR, FTIR spectroscopy, and DLS article size measurement. Pharmacodynamic analysis in two human cancer cell lines with different TRAIL sensitivities showed that TRAIL-M-CTX has a significantly better anticancer efficacy than the individual CTX and TRAIL protein. Importantly, TRAIL-M-CTX showed synergistic effects against TRAIL-insensitive cells (MCF-7). A study of cellular uptake implied that the modified micelles were internalized into MCF-7 cells more effectively than unmodified micelles, owing to the coupled TRAIL protein. A cell cycle assay of MCF-7 cells revealed that TRAIL-M-CTX significantly increased the sub-G1 population compared with CTX or TRIAL, thus, facilitating cancer cell apoptosis. These results suggest that TRAIL-M-CTX micelles have potential as a cancer chemotherapy formulation.

Design and evaluation of mPEG-PLA micelles functionalized with drug-interactive domains as improved drug carriers for docetaxel delivery.

Polymeric micelles are very attractive drug delivery systems for hydrophobic agents, owing to their readily tailorable chemical structure and ease for scale-up preparation. However, the intrinsic poor stability of drug-loaded micelles presents one of the major challenges for most micellar systems in the translation to clinical applications. In this study, a simple, well-defined, and easy-to-scale up 9-Fluorenylmethoxycarbonyl (Fmoc) and tert-butoxycarbonyl (Boc) containing lysine dendronized mPEG-PLA (mPEG-PLA-Lys(FB)2) micellar formulation was designed and prepared for docetaxel (DTX) delivery, in an effort to improve the stability of the micelles, and its physicochemical properties, pharmacokinetics, and anti-tumor efficacy against SKOV-3 ovarian cancer were evaluated. MPEG-PLA-Lys(FB)2 was synthesized via a three-step synthetic route, and it actively interacted with DTX in aqueous media to form stable micelles with small particle sizes (~17-19 nm) and narrow size distribution (PI < 0.1), which can be lyophilized and easily reconstituted in saline without significant change in particle size distribution. In vitro drug-release study demonstrated that mPEG-PLA-Lys(FB)2 micelles achieved delayed and sustained release manner of DTX in comparison with mPEG-PLA micelles. Further in vivo xenograft tumor model in nude mice DTX/mPEG-PLA-Lys(FB)2 micelles demonstrated significantly higher inhibitory effect on tumor growth than the marketed formulation Taxotere. Thus, our system may hold promise as a simple and effective delivery system for DTX with a potential for translation into clinical study.

Curcumin-Loaded Blood-Stable Polymeric Micelles for Enhancing Therapeutic Effect on Erythroleukemia.

Curcumin has high potential in suppressing many types of cancer and overcoming multidrug resistance in a multifaceted manner by targeting diverse molecular targets. However, the rather low systemic bioavailability resulted from its poor solubility in water and fast metabolism/excretion in vivo has hampered its applications in cancer therapy. To increase the aqueous solubility of curcumin while retaining the stability in blood circulation, here we report curcumin-loaded copolymer micelles with excellent in vitro and in vivo stability and antitumor efficacy. The two copolymers used for comparison were methoxy-poly(ethylene glycol)-block-poly(ε-caprolactone) (mPEG-PCL) and N-(tert-butoxycarbonyl)-l-phenylalanine end-capped mPEG-PCL (mPEG-PCL-Phe(Boc)). In vitro cytotoxicity evaluation against human pancreatic SW1990 cell line showed that the delivery of curcumin in mPEG-PCL-Phe(Boc) micelles to cancer cells was efficient and dosage-dependent. The pharmacokinetics in ICR mice indicated that intravenous (i.v.) administration of curcumin/mPEG-PCL-Phe(Boc) micelles could retain curcumin in plasma much better than curcumin/mPEG-PCL micelles. Biodistribution results in Sprague-Dawley rats also showed higher uptake and slower elimination of curcumin into liver, lung, kidney, and brain, and lower uptake into heart and spleen of mPEG-PCL-Phe(Boc) micelles, as compared with mPEG-PCL micelles. Further in vivo efficacy evaluation in multidrug-resistant human erythroleukemia K562/ADR xenograft model revealed that i.v. administration of curcumin-loaded mPEG-PCL-Phe(Boc) micelles significantly delayed tumor growth, which was attributed to the improved stability of curcumin in the bloodstream and increased systemic bioavailability. The mPEG-PCL-Phe(Boc) micellar system is promising in overcoming the key challenge of curcumin's to promote its applications in cancer therapy.

A novel cabazitaxel-loaded polymeric micelle system with superior in vitro stability and long blood circulation time.

Cabazitaxel (CTX) is a second-generation semisynthetic taxane that demonstrates antitumor activity superior to docetaxel. However, the low aqueous solubility of CTX has hampered its use as a therapeutic agent. In this work, CTX-loaded N-t-butoxycarbonyl-L-phenylalanine end-capped monomethyl poly (ethylene glycol)-block-poly (D,L-lactide) (mPEG-PLA-Phe(Boc)/CTX) micelles were prepared to improve the solubility of CTX while retaining its superior stability before accessing the tumor site. The mPEG-PLA-Phe(Boc)/CTX micelles showed excellent stability in vitro compared with mPEG-PLA/CTX micelles. When stored at 25 °C, the mPEG-PLA/CTX micelles tended to aggregate within 1 h, whereas the mPEG-PLA-Phe(Boc)/CTX micelles were uniformly transparent even after three weeks. Dilution of mPEG-PLA/CTX micelles widened their size distribution and decreased the encapsulation efficiency, while significant change was not found in mPEG-PLA-Phe(Boc)/CTX micelles, even when diluted 1000-fold. Pharmacokinetic results in Sprague-Dawley rats indicated that, compared with Jevtana(®), intravenous administration of mPEG-PLA-Phe(Boc)/CTX micelles stably retained the CTX in plasma with 26.03-fold larger of the area under the time-concentration curve, 2.13-fold longer of the half-life, and 9.99-fold higher of the maximum concentration. In conclusion, mPEG-PLA-Phe(Boc) micelle may be a potential nanocarrier not only to improve the solubility of CTX but also to prolong the blood circulation time, which results in improved biological activity.

Preparation, characterization, in vivo pharmacokinetics, and biodistribution of polymeric micellar dimethoxycurcumin for tumor targeting.

Dimethoxycurcumin (DMC) is an analog of curcumin with superior efficacy in various disease models. Currently, drug delivery system research on DMC is very limited, and it has become a huge challenge to realize further developments and clinical applications. In the present study, a kind of amphiphilic block copolymer, N-t-butoxycarbonyl-phenylalanine terminated monomethoxyl poly (ethylene glycol)-b-poly (ε-caprolactone), or mPEG-PCL-Phe(Boc), was prepared from monomethoxyl poly (ethylene glycol)-b-poly (ε-caprolactone) (mPEG-PCL) with its hydroxyl terminal chemically converted into N-t-butoxycarbonyl-phenylalanine (Boc-Phe). This copolymer was determined to have a fairly low critical micelle concentration (2.56×10(-3) mg/mL) and passive targeting potential to tumor tissue, and thus was applied to develop a polymeric micellar formulation of DMC for the first time. The DMC-loaded micelles prepared by thin-film hydration method had typical shell-core structure, with an average particle size of 17.9±0.4 nm and a polydispersity index of 0.045±0.011. The drug loading capacity and entrapment efficiency were 9.94%±0.15% and 97.22%±0.18%, respectively, indicating a high-affinity interaction between DMC and the copolymer. At a concentration of 2 mg/mL, the reconstituted micelle solution could be maintained for at least 10 days at room temperature, and displayed a low initial burst release followed by a sustained release in vitro. Pharmacokinetic study in rats revealed that in vivo drug exposure of DMC was significantly increased and prolonged by intravenously administering DMC-loaded micelles when compared with the same dose of free DMC dissolved in dimethyl sulfoxide. Furthermore, in vivo distribution results from tumor-bearing nude mice demonstrated that this micellar formulation significantly changed the biodistribution profile of DMC and increased drug accumulation in tumors. Therefore, the polymeric micellar formulation of DMC, based on the amphiphilic block copolymer, mPEG-PCL-Phe(Boc), could provide a desirable method for delivering DMC, especially for applications in cancer therapy.

Accelerated Recovery of Endothelium Function after Stent Implantation with the Use of a Novel Systemic Nanoparticle Curcumin.

Curcumin was reported to exhibit a wide range of pharmacological effects including antioxidant, anti-inflammatory, and antiproliferative activities and significantly prevent smooth muscle cells migration. In the present study, a novel kind of curcumin loaded nanoparticles (Cur-NP) has been prepared and characterized with the aim of inhibiting inflammation formation and accelerating the healing process of the stented arteries. Cur-NP was administrated intravenously after stent implantation twice a week and detailed tissue responses were evaluated. The results demonstrated that intravenous administration of Cur-NP after stent implantation accelerated endothelial cells restoration and endothelium function recovery and may potentially be an effective therapeutic alternative to reduce adverse events for currently available drug eluting stents.

Anti-CD133 antibody immobilized on the surface of stents enhances endothelialization.

Drug eluting stents successfully reduce restenosis at the cost of delayed reendothelialization. In recent years, a novel concept to enhance reendothelialization using anti-CD34 antibody coated stents which capture circulating progenitor cells (EPCs) has been developed with conflicting clinical results. CD133 is a glycoprotein expressed on circulating hematopoietic and putative endothelial-regenerating cells and may be superior to CD34 for EPCs capture stents. In the present study, anti-CD133 antibody has been successfully immobilized to the biodegradable polymeric coating material by covalent conjugation. We explore whether anti-CD133 antibody coated stents (CD133 stents) might accelerate reendothelialization in comparison with bare metal stents (BMS) through the superior ability to capture EPCs. The in vitro cell culture results indicate that anti-CD133 antibody functionalized polymer film significantly promotes CD133 positive cells attachment and growth compared with the unfunctionalized polymer film. In the semi-in vivo arteriovenous shunt model CD133 stents demonstrate much quicker specific capturing of EPCs from the blood stream than BMS within 6 hours. In a porcine coronary artery injury model CD133 stents show more effective reendothelialization in short term compared with BMS, while no significant difference in endothelial function recovery was observed between these two groups within 6-month followup.

Synthetic ePTFE grafts coated with an anti-CD133 antibody-functionalized heparin/collagen multilayer with rapid in vivo endothelialization properties.

An anti-CD133 antibody multilayer functionalized by heparin/collagen on an expanded polytetrafluoroethylene (ePTFE) graft was developed to accelerate early endothelialization. The surface modification of ePTFE grafts demonstrated that the multilayer is stable in static incubation and shaking conditions and that the anti-CD133 antibodies were successfully cross-linked onto the surface. Blood compatibility tests revealed that the coimmobilized heparin/collagen films in the presence or absence of anti-CD133 antibodies prolonged the blood coagulation time and that there was less platelet activation and aggregation, whereas the hemolysis rate was comparable with the bare ePTFE grafts. Cellular proliferation was not inhibited, as the heparin/collagen synthetic vascular grafts coated with CD133 antibody showed little cytotoxicity. The endothelial cells adhered well to the modified ePTFE grafts during a cell adhesion assay. A porcine carotid artery transplantation model was used to evaluate the modified ePTFE grafts in vivo. The results of histopathological staining and scanning electron microscopy indicated that the anti-CD133 antibody was able to accelerate the attachment of vascular endothelial cells onto the ePTFE grafts, resulting in early rapid endothelialization. The success of the anti-CD133 antibody-functionalized heparin/collagen multilayer will provide an effective selection system for the surface modification of synthetic vascular grafts and improve their use in clinical applications.

Anti-inflammatory effects of arsenic trioxide eluting stents in a porcine coronary model.

Previous research from our group has demonstrated arsenic trioxide eluting stents significantly reduced neointimal area and thickness compared with bare metal stents. In the present study, the anti-inflammatory effects of arsenic trioxide in vitro and arsenic trioxide eluting stents in a porcine coronary model have been explored. Sixty-five pigs underwent placement of 139 oversized stents in the coronary arteries with histologic analysis, endothelial function analysis, and immunohistochemical and western blot analyses. Arsenic trioxide eluting stents effectively inhibited local inflammatory reactions, while no significant difference in endothelialization and endothelial function between arsenic trioxide eluting stents and bare metal stents was observed. Arsenic trioxide eluting stents favorably modulate neointimal formation due to less augmentation of early inflammatory reactions, and quick endothelialization of the stent surface, which might contribute to long-term safety and efficacy of drug eluting stents.

Heparin-immobilized polymers as non-inflammatory and non-thrombogenic coating materials for arsenic trioxide eluting stents.

We have synthesized heparin-immobilized copolymers of L-lactide (LA) and 5-methyl-5-benzyloxycarbonate-1,3-dioxan-2-one (MBC) as non-inflammatory and non-thrombogenic biodegradable coating materials. These copolymers were used in fabricating arsenic trioxide (As(2)O(3))-eluting stents to reduce the late-stage adverse events, such as thrombosis, localized hypersensitivity and inflammation, that occur when applying stents to treat coronary artery diseases. Heparinized copolymers effectively reduced platelet adhesion and protein adsorption while increasing the plasma recalcification time and thromboplastin time in vitro. Histological analysis of the polymer-coated stents in a porcine coronary artery injury model indicated that one heparinized copolymer (Hep-Co90, LA:MBC=90:10), with the highest LA content of 90% and the lowest degradation rate, induced the least foreign body reactions and inflammation, which were as small as those induced by bare metal stents. Consequently, Hep-Co90 was used as the stent coating material for local As(2)O(3) delivery. Histomorphometric evaluations suggested no significant difference between bare metal stents and As(2)O(3)-eluting stents at 1 and 3 months post-implantation. At 6 months, the lumen area in the porcine coronary arteries treated with As(2)O(3)-eluting stents is 32.4% higher than those treated with bare metal stents while the neointimal area, neointimal thickness and stenosis rate decreased by 25.8%, 32.5% and 31.2%, respectively. The As(2)O(3)-eluting stent using Hep-Co90 as the drug carrier and stent coating material presented in this study represents a novel promising device in preventing in-stent restenosis.