A microRNA-21-responsive doxorubicin-releasing sticky-flare for synergistic anticancer with silencing of microRNA and chemotherapy

A sticky-flare gold nanoparticle probe(AuNP-probe) is designed by the combination of locked nucleic acid functionalized silencing of microRNA technology for intracellular microRNA-21(miRNA-21) sensitively detecting, fluorescence imaging,localizing and silencing. The limit of detection is as low as 0.01 n M. Overexpressed miRNA-21 in cancer cells serves as endogenous drug release stimuli to trigger the release of probe-loaded doxorubicin(Dox), which soon translocates into cell nuclei. This multifunctional Dox-loaded AuNP-probe(Dox-AuNP-probe) could induce cancer cell apoptosis effectively through the synergistic effect of gene silencing and chemotherapy. This Dox-AuNP-probe exhibits superior drug potency compared to free Dox molecules, with a cell inhibition rate of 57%(but only 20% for Dox) to wild-type cancer cells and 30%(but 0% for Dox) to drug-resistent cancer cells after 72 h, and this strategy not only has the function of sensing, but also can effectively bypass drug resistance. In MCF-7 xenograft tumor-bearing mice, the Dox-AuNP-probes show greater inhibition for tumor tissues than miRNA-21 targeted AuNP-probes(Targeting-AuNP-probe) or free Dox molecules. Therefore, the Dox-AuNP-probe represents a promising nanotheranostic platform for future applications in cancer molecular imaging and therapy, especially providing a potential strategy to treat resistant cancers.     

A tumor mRNA-dependent gold nanoparticle-molecular beacon carrier for controlled drug release and intracellular imaging

We demonstrate a tumor mRNA-dependent drug carrier for controlled release of doxorubicin (Dox) and intracellular imaging based on gold nanoparticle-molecular beacon. Fluorescent Dox is released effectively and induces apoptosis in breast cancer cells but not in normal cells. Significantly, the release of Dox is correlated positively with the quantities of tumor mRNA, which is according to various stages of tumor progression, and so can decrease effectively side effects of Dox.     

Liposomes‐Camouflaged Redox‐Responsive Nanogels to Resolve the Dilemma between Extracellular Stability and Intracellular Drug Release

Liposomes have shown great promises for pharmaceutical applications, but still suffer from the poor storage stability, undesirable drug leakage, and uncontrolled drug release. Herein, liposomes‐camouflaged redox‐responsive nanogels platform (denoted as “R‐lipogels”) is prepared to integrate the desirable features of sensitive nanogels into liposomes to circumvent their intrinsic issues. The results indicate that drug‐loaded R‐lipogels with controlled size and high stability not only can achieve a very high doxorubicin (DOX)‐loading capacity (12.9%) and encapsulation efficiency (97.3%) by ammonium sulfate gradient method and very low premature leakage at physiological condition, but also can quickly release DOX in the reducing microenvironment of tumor cells, resulting in effective growth inhibition of tumor cells. In summary, the strategy given here provides a facile approach to develop liposomes–nanogels hybrid system with combined beneficial features of stealthy liposomes and responsive nanogels, which potentially resolves the dilemma between systemic stability and intracellular rapid drug release.     

Gadolinium-based cancer therapeutic liposomes for chemotherapeutics and diagnostics

Gadolinium (Gd)-based cancer therapeutic liposomes can be used for chemotherapeutics and diagnostics. In this study, dual functional liposomes co-encapsulating doxorubicin (Dox) and Gd were prepared by Dox-transition metal complexation. Preparation conditions were optimized to obtain liposomes containing high concentrations of Dox and Gd. The optimized liposomes Gd250 co-encapsulated 3.6 mM of Dox and 1.9 mM of Gd. The magnetic resonance (MR) properties of Gd250 liposomes were determined using a 4.7 T MR system. Cellular uptake of Dox was determined using a flow cytometer and a confocal microscopy and that of Gd was measured using an inductively coupled plasma-atomic emission spectrometer. Although encapsulated Gd exhibited lower relaxivity than MRbester?, which is widely used for clinical diagnosis, because of limited diffusion across the liposome membrane, Gd250 liposomes showed much higher cellular uptake than that of MRbester?. In Gd250 liposomes, Gd was highly accumulated in B16F10 cells, which could provide improved contrast sensitivity for molecular imaging. Additionally, in Gd250 liposomes, Dox was highly internalized, which could enhance its cancer therapeutic effects. Consequently, we suggest that dual functional liposomes can be used as therapeutic and diagnostic carriers.     

Protein release from biodegradable dextran nanogels

The use of drugs with intracellular targets will strongly depend on the availability of delivery systems that are able to deliver them to specific intracellular sites at an optimal rate. Biodegradable dextran nanogels were prepared using liposomes as a nanoscaled reactor.1,2 These nanogels were obtained by UV polymerization of dextran hydroxyethylmethacrylate (dex-HEMA) containing 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC) liposomes. We found the encapsulation efficiency of bovine serum albumin (BSA) and lysozyme in the dextran nanogels to be about 50%. Specifically, the release of BSA and lysozyme from the dextran nanogels was clearly governed by the cross-link density of the tiny gels. Depending on the size of the encapsulated protein, the cross-link density of the dextran network, and the presence or absence of a lipid coating, proteins were released from the nanogels over days to weeks. Interestingly, when sufficiently diluted, dextran nanogels did not aggregate in human serum, which is of major importance when one considers intravenous administration of such nanogels. Also, reconstitution of lyophilized dextran nanogels seemed perfectly possible, which is also an important finding since dextran nanogels will have to be stored in dry form. Because dextran nanogels can be taken up by cells, they are promising materials for controlled intracellular release of proteins.     

Novel nanogels as drug delivery systems for poorly soluble anticancer drugs

Two types of novel nanogels were prepared using shell cross-linking of Pluronic F127 micelles with polyethylenimine (PEI) (F127/PEI nanogel), and penetrating network of poly(butylcyanoacrylate) (PBCA) in Pluronic F127 micelles (F127/PBCA nanogel). Poorly soluble anticancer drug, paclitaxel (PTX) and 10-hydroxycamptothecin (HCPT), were used as model drugs and incorporated into nanogels. The results obtained from FT-IR spectroscopy confirmed that the drugs were molecularly dispersed in the nanogels. DLS measurements demonstrated that the nanogel size distribution was narrow with average diameter less than 200 nm. TEM images indicated that the nanogels were spherical in shape and had smooth surfaces. The drug-loaded nanogels showed sustained release profiles compared with the free drugs as revealed by in vitro release experiments. Cytotoxicity tests showed that the cytotoxicity of drug-loaded nanogels against cancer cell in vitro was much higher than that of the free drug. The data demonstrate that these novel nanogels improved stability towards dilution, increased solubility and showed better cellular uptake by cells compared with free drug.     

Cyclodextrin Polymers as Delivery Systems for Targeted Anti-Cancer Chemotherapy

In the few last years, nanosystems have emerged as a potential therapeutic approach to improve the efficacy and selectivity of many drugs. Cyclodextrins (CyDs) and their nanoparticles have been widely investigated as drug delivery systems. The covalent functionalization of CyD polymer nanoparticles with targeting molecules can improve the therapeutic potential of this family of nanosystems. In this study, we investigated cross-linked γ- and β-cyclodextrin polymers as carriers for doxorubicin (ox) and oxaliplatin (Oxa). We also functionalized γ-CyD polymer bearing COOH functionalities with arginine-glycine-aspartic or arginine moieties for targeting the integrin receptors of cancer cells. We tested the Dox and Oxa anti-proliferative activity in the presence of the precursor polymer with COOH functionalities and its derivatives in A549 (lung, carcinoma) and HepG2 (liver, carcinoma) cell lines. We found that CyD polymers can significantly improve the antiproliferative activity of Dox in HepG2 cell lines only, whereas the cytotoxic activity of Oxa resulted as enhanced in both cell lines. The peptide or amino acid functionalized CyD polymers, loaded with Dox, did not show any additional effect compared to the precursor polymer. Finally, studies of Dox uptake showed that the higher antiproliferative activity of complexes correlates with the higher accumulation of Dox inside the cells. The results show that CyD polymers could be used as carriers for repositioning classical anticancer drugs such as Dox or Oxa to increase their antitumor activity.     

Hybrid nanogels with physical and chemical cross-linking structures as nanocarriers

Polymerizable nanogels were prepared by self-assembly of cholesteryl group-bearing pullulan (CHP) with methacryloyl groups (CHPMA). The CHPMA nanogel was polymerized with 2-methacryloyloxyethyl phosphorylcholine (MPC) by radical polymerization in dilute aqueous solution. The solution properties of the polymers in water were investigated by TEM, SEC-MALS, and fluorescence quenching technique. Monodispersed hybrid nanogels of CHPMA-MPC (CM nanogels) (25-30 nm in radius of gyration) were obtained by using CHPMA nanogel as a seed-nanogel. CM nanogels have a dual cross-linking structure that is physically cross-linked with the cholesteryl groups and chemically cross-linked with the MPC polymer chains. CM nanogels trap heat-denatured carbonic anhydrase B (CAB) and prevent their aggregations. The nanogels maintained the ability of trapping and releasing enzymes by host-guest interaction of cholesteryl group and cyclodextrin.     

Infrared Responsive Choline Phosphate Lipids for Synergistic Cancer Therapy

Choline phosphate lipids have been designed and developed as new-generation zwitterionic nanocarriers with excellent biocompatibility and bioorthogonality to provide a more programmable performance for cancer therapy. However, there is a lack of spatiotemporal and reversible control for drug release at target tumor cells, which can lead to severe adverse effects to normal tissue and discounted treatment outcome. Here, light-inducible Lip-cRGDfk/ICG/Dox liposomes were developed for synergistic cancer therapy. ICG can effectively convert light energy into selective heating in a local environment upon laser irradiation, thus inducing thermal ablation of tumor cells, and further reversibly trigger the spatiotemporal release of anticancer drugs (Dox) at tumor cells due to the conformation transformation of CP lipids to synergistically kill tumor cells. That Lip-cRGDfk/ICG/Dox exhibited a significant improvement for breast cancer therapy in vitro and in vivo is also demonstrated, thus it can serve as an efficient platform to noninvasively and spatiotemporally control the activation of cytotoxicity at tumor cells for precision cancer therapy.     

Theranostic hyaluronic acid prodrug micelles with aggregation-induced emission characteristics for targeted drug delivery

Theranostic hyaluronic acid (HA) prodrug micelles with pH-responsive drug release and aggregation-induced emission (AIE) properties were prepared by chemical graft of biomimetic phosphorylcholine (PC), anticancer drug doxorubicin (DOX) and AIE fluorogen tetraphenylene (TPE) to the HA backbone. DOX was conjugated to the HA backbone by a hydrazone bond which can be hydrolyzed under acidic environment and result in pH-triggered smart release of DOX. The TPE units with typical AIE characteristics were applied for real time drug tracking in cancer cells. The HA-based prodrugs could self-assemble into micelles in aqueous solution as confirmed by the dynamic light scattering (DLS) and transmission electron microscopy (TEM). The intracellular distribution of HA prodrug micelles could be clearly observed by fluorescence microscopy based on the strong fluorescence of TPE. Moreover, after treated with the micelles, stronger fluorescence of TPE in CD44 overexpressed MDA-MB-231 cancer cells was observed, compared to the CD44 negative cell line, NIH3T3 cells, suggesting efficient cell uptake of HA prodrug micelles by receptor-mediated endocytosis. The cell viability results indicated that the prodrug micelles could inhibit the proliferation of the cancer cells effectively. Such pH-triggered theranostic drug delivery system with AIE features can provide a new platform for targeted and image-guided cancer therapy.     

NIR‐Induced Disintegration of CuS‐Loaded Nanogels for Improved Tumor Penetration and Enhanced Anticancer Therapy

Nanocarrier‐based cancer therapy suffers from poor tumor penetration and unsatisfied therapeutical efficacy, as its vascular extravasation efficiency is often compromised by the intrinsic physiological heterogeneity in tumor tissues. In this work, novel near infrared (NIR)‐responsive CuS‐loaded nanogels are prepared to deliver anticarcinogen into the tumor. These hybrid polymeric nanogels possess high photothermal conversion efficiency, and are able to load a large amount of antitumor drug (e.g., doxorubicin [DOX]). More importantly, the thermal heat could induce self‐destruction of the big‐size framework of hybrid nanogels into small nanoparticles, which greatly facilitates tumor penetration to release DOX deep inside the tumor, as validated by photoacoustic (PA) imaging which exhibits 26.3 times enhancement at the interior region compared to signals of groups without laser irradiation. Such structural alteration, combined with strong photothermal and chemotherapy effects, leads to remarkable inhibition of tumor growth in mice. As a result, this NIR‐induced disintegration of CuS‐loaded nanogels provides a novel drug delivery strategy and might open a new window for clinical cancer treatment.     

Photodegradable polyurethane self-assembled nanoparticles for photocontrollable release

Light-responsive drug delivery systems are particularly appealing that are capable of releasing active molecules at the appropriate site and rate. We synthesized a series of photodegradable polymers that can form nanoparticles for drug encapsulation. These particles in aqueous solutions are stable in buffers with different pHs or at evaluated temperatures, while light can trigger the crash of particles and the release of encapsulated substances. The release efficiency can reach up to 90% based on Nile red fluorescence intensity upon 15 min light irradiation. Nanoparticle uptake by phagocytic cells and light-triggered release in cells were observed by fluorescence emission of the hydrolyzed fluorescein diacetate upon photoinduced degradation of these nanoparticles. No significant toxicity of these nanoparticles was found at the concentrations up to 1000 μg/mL before or after light irradiation. Further encapsulation and triggered release of a bioactive model drug (Tagalsin G) was evaluated for RAW 264.7 cells. Tagalsin G encapsulated in nanoparticles did not show cytotoxity to cells, while light triggered the release of Tagalsin G increasing cell death dramatically from 9% to 67%. Our model studies show a new promising strategy to trigger drug release in cells.     

Facile Synthesis of Resveratrol Nanogels with Enhanced Fluorescent Emission

Herein, a kind of fluorescent resveratrol nanogels via one‐pot thiol‐ene Michael addition polymerization of resveratrol triacrylate, 1,6‐hexanedithiol, and methoxyl poly(ethylene glycol) acrylate is prepared. The resultant nanogels can be well‐dispersed in water with a hydrodynamic radius of around 68 nm, and the nanogels are stable in both water and organic solvents. Moreover, the resveratrol nanogels exhibit elevated fluorescence intensity compared to free resveratrol, and the quantum yield of resveratrol nanogels is estimated to be 5.8 times as that of free resveratrol dispersed in water. Fluorescence image results also demonstrate that the resveratrol nanogels can be used for cell imaging in MCF‐7 human breast cancer cells. Therefore, the resveratrol nanogels are expected to be used as a trackable drug delivery system.     

Photosensitive cross-linked block copolymers with controllable release

We intend to form photosensitive block copolymer micelles for controllable release of encapsulated substances. Here, we designed and synthesized a new photocleavable cross-linker (2-nitrophenyl ethylene glycol dimethacrylate) for methyl methacrylate (MMA) atom transfer radical polymerization. Four different ratios (0:1, 1:26, 1:16, 1:8.8) of the photocleavable cross-linker to MMA monomer were used and four block copolymers (P0, P1, P2, P3) were synthesized with PEO-Br as the macroinitiator. Gel permeation chromatography and (1) H NMR studies showed that linear polymer molecules could be cross-linked by the photocleavable linker. The fluorescence studies of the encapsulated Nile Red (NR) showed that there were lower critical micelle concentrations for the polymer P1, P2 and P3 than polymer P0. And dynamic light scattering and SEM confirmed the formation of polymer micelles. Photolysis experiments demonstrated that NR encapsulated in the polymer micelles could be released upon UV irradiation (365 nm, 11 mW cm(-2)) due to the breakage of the photocleavable linker and the generation of more hydrophilic acid moieties, which destabilized polymer micelles. Our study shows a new strategy for the possibility of photocontrollable drug release for hydrophobic drugs.     

Reducible polyethylenimine hydrogels with disulfide crosslinkers prepared by michael addition chemistry as drug delivery carriers: Synthesis,properties, and in vitro release

Degradable hydrogels crosslinked with disulfide bonds were prepared by Michael addition between amine groups of branched polyethylenimine and carbon–carbon double bonds of N,N′‐bis(acryloyl)cystamine. The influences of the chemical composition of the resulted hydrogels on their properties were examined in terms of morphology, surface area, swelling kinetics, and degradation. The hydrogels were uniformly crosslinked and degraded into water‐soluble polymers in the presence of the reducing agent of dithiothreitol, which improved the control over the release of encapsulated drug. The degradation of hydrogels can trigger the release of encapsulated molecules, as well as facilitate the removal of empty vehicles. Results obtained from in vitro drug release suggested that the disulfide crosslinked hydrogels exhibited an accelerated release of encapsulated drug in dithiothreitol‐containing PBS buffer solution. Moreover, the drug release rate decreased gradually with increasing crosslinking density. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4074–4082, 2009     

ROS-responsive selenium-containing polyphosphoester nanogels for activated anticancer drug release

Nowadays, the stability and on-demand release of drug carriers are still to be solved. To meet the demand of these issues, we developed a reactive oxygen species (ROS) responsive selenium-containing polyphosphoesters nanogel (PSeP) by a facile one-step ring-opening polymerization of the novel monomer 4-selenoctane-1,8-diyl bis(propylphosphatelane) (Se-COP) with polyethylene glycol (mPEG) employed as the macroinitiator. Their structure was confirmed by NMR, FT-IR and GPC. The crosslinked core-shell structure imparted the nanogels with excellent dimensional stability according to the dynamic light scattering (DLS) and transmission electron microscopy (TEM). Moreover, the selenide groups endowed the nanogels with rich ROS responsiveness when subjected to the stimuli of H₂O₂, thus the drug-loaded PSeP nanogels displayed swollen behaviors leading to an activated doxorubicin hydrochloride (DOX · HCl) release. The release mechanisms fitted by the Ritger-Peppas power-law model also proved the swollen release process. MTT assays exhibited that the PSeP nanogels were nontoxic up to a tested concentration of 50 μg mL^?1 by A549 and HEK293, and the DOX-loaded PSeP had a high anti-cancer behaviour against A549 cancer cells. Additionally, these nanogels possessed enhanced intracellular drug release by CLSM. Therefore, these results highlighted that the selenium-containing polyphosphoesters nanogels could be a potential platform for the ROS-sensitive drug delivery.     

Synthesis and swelling behavior of temperature responsive κ-carrageenan nanogels

Crosslinked κ-carrageenan hydrogel nanoparticles (nanogels) with an average size smaller than 100 nm were prepared using reverse microemulsions combined with thermally induced gelation. The size of the nanogels varied with biopolymer concentration at a constant water/surfactant concentration ratio. The nanogels were found to be thermo-sensitive in a temperature range acceptable for living cells (37-45°C) undergoing reversible volume transitions in response to thermal stimuli. This opens the possibility to explore the application of these nanogels in smart therapeutics such as thermo-sensitive drug carriers. As such, the sustained release of methylene blue from the nanogels was evaluated in in vitro conditions as proof of concept experiments and the release rate was found to be controlled with temperature.     

Mesoporous γ‐Iron Oxide Nanoparticles for Magnetically Triggered Release of Doxorubicin and Hyperthermia Treatment

Mesoporous iron‐oxide nanoparticles (mNPs) were prepared by using a modified nanocasting approach with mesoporous carbon as a hard template. mNPs were first loaded with doxorubicin (Dox), an anticancer drug, and then coated with the thermosensitive polymer Pluronic F108 to prevent the leakage of Dox molecules from the pores that would otherwise occur under physiological conditions. The Dox‐loaded, Pluronic F108‐coated system (Dox@F108‐mNPs) was stable at room temperature and physiological pH and released its Dox cargo slowly under acidic conditions or in a sudden burst with magnetic heating. No significant toxicity was observed in vitro when Dox@F108‐mNPs were incubated with noncancerous cells, a result consistent with the minimal internalization of the particles that occurs with normal cells. On the other hand, the drug‐loaded particles significantly reduced the viability of cervical cancer cells (HeLa, IC₅₀=0.70 μm ), wild‐type ovarian cancer cells (A2780, IC₅₀=0.50 μm ) and Dox‐resistant ovarian cancer cells (A2780/AD, IC₅₀=0.53 μm ). In addition, the treatment of HeLa cells with both Dox@F108‐mNPs and subsequent alternating magnetic‐field‐induced hyperthermia was significantly more effective at reducing cell viability than either Dox or Dox@F108‐mNP treatment alone. Thus, Dox@F108‐mNPs constitute a novel soft/hard hybrid nanocarrier system that is highly stable under physiological conditions, temperature‐responsive, and has chemo‐ and thermotherapeutic modes of action.     

Biomimetic Mineralization of Protein Nanogels for Enzyme Protection

Protein nanogels have found a wide variety of applications, ranging from biocatalysis to drug/protein delivery. However, in practical applications, proteins in nanogels may suffer from enzymic hydrolysis and denaturation. Inspired by the structure and functionalities of the fowl eggshells, biomimetic mineralization of protein nanogels was studied in this research. Protein nanogels with embedded porcine pancreas lipase (PPL) in the cross-linked nanostructures were synthesized through the thiol–disulfide reaction between thiol-functionalized PPL and poly(N-isopropylacrylamide) with pendant pyridyl disulfide groups. The nanogels were further reacted with reduced bovine serum albumin (BSA) and BSA molecules were coated on the nanogels. Mineralization of BSA leads to the synthesis of biomineralized shells on the nanogels. With the growth of CaCO₃ on the shells, the nanogels aggregate into suprastructures. Thermogravimetric analysis, XRD, dynamic light scattering, and TEM were employed to study the mechanism of the biomineralization process and analyze the structures of the mineralized nanogels. The biomineralized shells can effectively protect the PPL molecules from hydrolysis by trypsin; meanwhile, the nanosized channels on the mineralized shells allow the transport of small-molecule substrates across the shells. Bioactivity measurements indicate that PPL in the nanogels maintains more than 80 % bioactivity after biomineralization.     

聚多巴胺-阿霉素纳米颗粒对癌细胞的化疗-光热治疗协同作用

通过在水相中加入乙醇和氨水, 将单分子多巴胺聚合成具有良好光热转换能力的聚多巴胺纳米颗粒(PDA), 并利用π-π作用与共价键作用, 将抗癌药物阿霉素(Dox)负载到聚多巴胺纳米颗粒的表面, 制备了聚多巴胺纳米颗粒负载阿霉素(PDA-Dox), 研究了PDA-Dox的药物缓释性能. 结果发现, PDA-Dox能够在酸性环境下增加药物释放. 细胞实验显示, PDA-Dox配合激光照射, 能够通过化疗和光热治疗高效地杀死癌细胞.