Fluorescence color change of supramolecular polymer networks controlled by crown ether-cation recognition

We report a fluorescent supramolecular polymer networks (SPNs) system based on crown ether-cation recognition. The polymer side chains bear ammonium cations, which can be recognized by host molecules with a B15C5 unit and a quinoline group at each end. The quinoline group makes the host molecule exhibit blue fluorescence. After the formation of SPNs, the recognition of the crown ether-cation transforms the blue fluorescence into yellow fluorescence. The accompanying fluorescence color change during the formation of SPNs makes it with potential applications in the fields of display, printing, information storage, and bioimaging.

Bioresponsive and multifunctional cyclodextrin-based non-viral nanocomplexes in cancer therapy: Building foundations for gene and drug delivery, immunotherapy and bioimaging

The interest towards application of nanomaterials in field of cancer therapy is that the drawbacks of conventional therapies including chemoresistance, radio-resistance and lack of specific targeting of tumor cells can be solved by nanotechnology. Cyclodextrins (CDs) are amphiphilic cyclic oligosaccharides that can be present in three forms of α-, β- and γ-CDs, and they can be synthesized from natural sources. The application of CDs in cancer shows an increasing trend due to benefits of these nanocomplexes in improving solubility and bioavailability of current bioactives and therapeutics for cancer. CDs are widely utilized in delivery of drugs and genes in cancer therapy, and by targeted delivery of these therapeutics into target site, they improve anti-proliferative and anti-cancer potential. The blood circulation time and tumor site accumulation of therapeutics can be improved using CD-based nanostructures. More importantly, the stimuli-responsive types of CDs including pH-, redox- and light-sensitive types can accelerate release of bioactive compound at tumor site. Interestingly, the CDs are able to mediate photothermal and photodynamic impact in impairing tumorigenesis in cancer, enhancing cell death and improving response to chemotherapy. In improving the targeting ability of CDs, their surface functionalization with ligands has been conducted. Moreover, CDs can be modified with green products such as chitosan and fucoidan, and they can be embedded in green-based nanostructures to suppress tumorigenesis. The internalization of CDs into tumor cells can occur through endocytosis and this can be clethrin-, caveolae- or receptor-mediated endocytosis. Furthermore, CDs are promising candidates in bioimaging, cancer cell and organelle imaging as well as isolating tumor cells. The main benefits of using CDs in cancer therapy including sustained and low release of drugs and genes, targeted delivery, bioresponsive release of cargo, ease of surface functionalization and complexation with other nanostructures. The application of CDs in overcoming drug resistance requires more investigation.

Supramolecular self-assemblies based on water-soluble pillar[6]arene and drug-drug conjugates for the combination of chemotherapy

Although some co-drug delivery systems have been reported to treat cancer, how to optimal design these nano-systems with enhanced therapeutic efficacy is still a major challenge. As for the nitrogen mustard drugs chlorambucil (Cb), the overexpressed glutathione (GSH) in cancer tissue is responsible for their detoxification and reduced bioavailability. In this paper, chlorambucil-oxoplatin (Cb-Pt) was prepared to fabricate water-soluble pillar[6]arene (WP[6]) based supramolecular drug-drug self-assemblies (SDSAs). Remarkably, after the transcytosis by cancer cells, SDSAs was reduced by GSH to re lease Cb and higher toxic cisplatin, accompanying with the declining GSH level and ascending ROS level. Moreover, in vitro and in vivo experiments demonstrated that SDSAs with oxidative stress amplification strategy exhibited excellent therapeutic effect. This strategy might be useful for the synergistic co-drug based chemotherapy field.

Targeting drug delivery system for platinum(Ⅳ)-Based antitumor complexes

Classical platinum(II) anticancer agents are widely-used chemotherapeutic drugs in the clinic against a range of cancers. However, severe systemic toxicity and drug resistance have become the main obstacles which limit their application and effectiveness. Because divalent cisplatin analogues are easily destroyed in vivo, their bioavailability is low and no selective to tumor tissues. The platinum(IV) prodrugs are attractive compounds for cancer treatment because they have great advantages, e.g., higher stability in biological media, aqueous solubility and no cross-resistance with cisplatin, which may become the next generation of platinum anticancer drugs. In addition, platinum(IV) drugs could be taken orally, which could be more acceptable to cancer patients, breaking the current situation that platinum(II) drugs can only be given by injection. The coupling of platinum(IV) complexes with tumor targeting groups avoids the disadvantages such as instability in blood, irreversible binding to plasma proteins, rapid renal clearance, and non-specific distribution in normal tissues. Because of the above advantages, the combination of platinum complexes and tumor targeting groups has become the hottest field in the research and development of new platinum drugs. These approaches can be roughly categorized into two groups: active and passive targeted strategies. This review concentrates on various targeting and delivery strategies for platinum(IV) complexes to improve the efficacy and reduce the side effects of platinum-based anticancer drugs. We have made a summary of the related articles on platinum(IV) targeted delivery in recent years. We believe the results of the studies described in this review will provide new ideas and strategies for the development of platinum drugs.

Construction of β-cyclodextrin-based supramolecular hyperbranched polymers self-assemblies using AB2-type macromonomer and their application in the drug delivery field

Despite some efforts have been made in the research of supramolecular hyperbranched polymers (SHPs) self-assemblies, the study which has not been consideration to date is the influence of incoming stimuli-responsive polymer chain on their self-assembly property undergo outer stimuli. The introduction of stimuli-responsive segments which could maintain their hydrophilic property are expected to affect the self-assembly behaviour of SHPs and expand their further biomedical application. In this paper, AB₂-type macromolecular monomer, LA-(CD-PDMA)₂, which consisted one lithocholic acid (LA) and two β-cyclodextrin terminated poly(2-(dimethylamino)ethyl methacrylate) segments (CD-PDMA) was synthesized. LA-(CD-PDMA)₂ based SHP were obtained based on the host-guest inclusion interactions of CD/LA moietes and with PDMA as pH-responsive hydrophilic chains. As a control to study the influence of incoming PDMA chains, both LA-(CD-PDMA)₂ based SHPs-1 and LA-CD₂ based SHPs-2 self-assemblies were comparatively investiged through 2D ¹H NMR ROESY, transmission electron microscopy (TEM) and dynamic light scattering (DLS). The results suggested that except for the higher drug loading efficiency LA-(CD-PDMA)₂ based SHPs-1 pocessing, the release rates of SHPs-1 increased notably at pH 5.0 than that of pH 7.4 due to the repulsion and stretch of protonated PDMA chains while the release rates of SHPs-2 showed no obvious difference. Finally, basic cell experiments demonstrated that the SHPs based self-assemblies can be internalized into cancer cells, indicating their potential application in the drug delivery field.

RAFT polymerization to form stimuli-responsive polymers

Stimuli-responsive polymers respond to a variety of external stimuli, which include optical, electrical, thermal, mechanical, redox, pH, chemical, environmental and biological signals. This paper is concerned with the process of forming such polymers by RAFT polymerization.

Drug induced self-assembly of triblock copolymers into polymersomes for the synergistic dual-drug delivery of platinum drugs and paclitaxel

Co-delivery of two drugs in one nanoparticle is increasingly used to overcome, for example, multi-drug resistance in cancer therapy and therefore suitable drug carriers need to be developed.

Photosensitizer cross-linked nano-micelle platform for multimodal imaging guided synergistic photothermal/photodynamic therapy

The multifunctional nano-micelle platform holds great promise to enhance the accuracy and efficiency of cancer diagnosis and therapy. In this work, an amphiphilic poly[(poly(ethylene glycol) methyl ether methacrylate)-co-(3-aminopropyl methacrylate)]-block-poly(methyl methacrylate) (P(PEGMA-co-APMA)-b-PMMA) block copolymer was synthesized by successive RAFT polymerizations and subsequent chemical modification. Then the multifunctional micelles with high solubility in physiological environments were developed by a self-assembly and crosslinking processes. The photosensitizer segment, 5,10,15,20-tetrakis (4-carboxyphenyl) porphyrin (TCPP), serves as a tetra-functional cross-linker, photodynamic agent, fluorescence indicator, as well as magnetic resonance (MR) contrast agent after labelling with manganese ions (Mn(2+)), while IR825 simultaneously locating in the interior of the fabricated micelles contributed to the photoacoustic (PA) imaging ability and the photothermal effect. The prepared nanoparticles show great stability in a physiological environment with uniform morphology and diameters of around 80 nm as disclosed by stability investigation, TEM and DLS analysis. IR825@P(PEGMA-co-APMA)-b-PMMA@TCPP/Mn nanoparticles displayed high in vivo tumor uptake with a long blood circulation half-life (∼3.64 h) by the EPR effect after intravenous (i.v.) injection, as revealed by fluorescence, MR and PA imaging models. In vivo anti-tumor effects were achieved via a combined photothermal and photodynamic therapy without noticeable dark toxicity, and this strategy was able to induce a remarkably improved synergistic therapeutic effect to both superficial and deep regions of tumors under mild conditions compared with either single photothermal or photodynamic mechanisms.

Poly[platinum(iv)-alt-PEI]/Akt1 shRNA complexes for enhanced anticancer therapy

Co-delivery of Akt1 shRNA and platinum(iv) prodrug using DP/Akt1 shRNA complexes for synergetic cancer inhibition.