Supramolecular organic frameworks improve the safety of clinically used porphyrin photodynamic agents and maintain their antitumor efficacy.

Despite that photodynamic therapy (PDT) has been applied for the treatment of cancer and skin diseases for more than two decades, all clinically used photodynamic agents (PDAs) suffer the drawback of skin phototoxicity of PDAs, which requires patients to avoid exposure to natural light for weeks after treatment, but has so far lacked effective suppression methods. Here, we report that three-dimensional diamondoid supramolecular organic frameworks (SOFs), that possess well-defined 2.1-nm porosity, can be used to suppress the skin phototoxicity of Photofrin, HiPorfin and Talaporfin, three porphyrin-based PDAs which clinically receive the most wide applications by injecting SOF after PDT, via an adsorption and retention mechanism. Fluorescence and dynamic light scattering experiments confirm that the SOFs have strong interaction with PDAs, and can adsorb PDAs at a micromolar concentration, whereas dialysis experiments support that the adsorption leads to an important retention effect. In vitro and in vivo experiments reveal that SOFs have high biocompatibility. Studies with healthy and tumor-bearing mouse models demonstrate that, when the PDAs are administrated at a dose comparable with the clinical one, SOF can remarkably suppress sunlight-induced skin phototoxicity, whereas the PDT efficacy of mice treated with SOF post-PDT is maintained. This work provides an efficient strategy for the improvement of the safety of clinically used PDAs.

A pH-responsive complex based on supramolecular organic framework for drug-resistant breast cancer therapy.

Chemotherapy is one of the main ways to treat breast cancer clinically. However, the multidrug resistance to anti-tumor drugs limits their clinical use. To overcome these drawbacks, development of drug delivery systems (DDSs) has attracted more and more attention in cancer therapy. At present, the preparation and purification process are complicated for many reported DDSs, while clinic calls for new DDSs that are more convenient for preparation. Here, a new pH-responsive supramolecular organic framework drug delivery complex loading doxorubicin (DOX) is fabricated. Anti-tumor activity of the system in vitro was investigated by cell cytotoxicity, uptake assay, and cell apoptosis analysis. The anti-tumor activity in vivo was investigated by inspecting nude mice body weight, tumor volume, and weight, also a preliminary mechanism probe was conducted by HE and TUNEL staining. The DOX@SOF displayed high stability, good biocompatibility, and pH regulated drug release. At acid condition, the hydrazone bonds would be broken, which result in the dissociation of SOF, and then the drugs would be released from the system. Furthermore, DOX@SOF enhanced cellular internalization. Both in vitro and in vivo experiments reflected that DOX@SOF could enhance the anti-tumor activity of DOX for the MCF-7/ADR tumor cells and tumors. This study provides a highly efficient strategy to prepare stimulus-responsive supramolecular drug delivery complex for treatment of drug-resistant cancer, the results presented inspiring scientific interests in exploring new drug delivery strategy and reversing multi-drug resistance for clinical chemotherapy.

A pH-responsive complex based on supramolecular organic framework for drug-resistant breast cancer therapy.

Chemotherapy is one of the main ways to treat breast cancer clinically. However, the multidrug resistance to anti-tumor drugs limits their clinical use. To overcome these drawbacks, the development of drug delivery systems (DDSs) has attracted more and more attention in cancer therapy. At present, the preparation and purification process are complicated for many reported DDSs, while the clinic calls for new DDSs that are more convenient for preparation. Here a new pH-responsive supramolecular organic framework drug delivery complex loading doxorubicin (DOX) is fabricated. Anti-tumor activity of the system in vitro was investigated by cell cytotoxicity, uptake assay, and cell apoptosis analysis. The anti-tumor activity in vivo was investigated by inspecting nude mice body weight, tumor volume and weight, also a preliminary mechanism probe was conducted by HE and TUNEL staining. The DOX@SOF displayed high stability, good biocompatibility and pH-regulated drug release. At acid condition, the hydrazone bonds would be broken, which result in the dissociation of SOF, and then the drugs would be released from the system. Furthermore, DOX@SOF enhanced cellular internalization. Both in vitro and in vivo experiments reflected that DOX@SOF could enhance the anti-tumor activity of DOX. for the MCF-7/ADR tumor cells and tumors. This study provides a highly efficient strategy to prepare a stimulus-responsive supramolecular drug delivery complex for the treatment of drug-resistant cancer, the results presented inspiring scientific interests in exploring new drug delivery strategies and reversing multi-drug resistance for clinical chemotherapy.

Flexible Organic Framework-Based Anthracycline Prodrugs for Enhanced Tumor Growth Inhibition.

A water-soluble flexible organic framework FOF-hz of low cytotoxicity has been synthesized from a pyridinium-derived tetracationic tetraaldehyde and a citric acid-derived tritopic acylhydrazine (1:2) through the formation of a hydrazone bond. Dynamic light-scattering experiments reveal that FOF-hz has a hydrodynamic diameter of 79 nm at 0.1 mM concentration of the tetrahedral precursor. Dialysis experiments show that the free acylhydrazine units of FOF-hz can react with the C-13 ketone units of anthracycle drugs, including doxorubicin (DOX), daunorubicin, epirubicin, and pirarubicin, at pH = 3.0 to conjugate the drugs in 78-85% yields. The resulting FOF-prodrugs exhibit remarkable acid-responsive deconjugation of the conjugated active agents. Laser confocal scanning microscopy and flow cytometric analysis support that FOF-hz displays enhanced permeability and retention effect, which helps to overcome the multidrug resistance of MCF-7/ADR tumor cells and leads to enhanced cytotoxicity for MCF-7/ADR cells. In vivo studies reveal a considerable improvement of the efficacy of the prodrug FOF-DOX for the inhibition of the growth of the MCF-7/ADR tumor.

A Woven Supramolecular Metal-Organic Framework Comprising a Ruthenium Bis(terpyridine) Complex and Cucurbit[8]uril: Enhanced Catalytic Activity toward Alcohol Oxidation.

The self-assembly of a diamondoid woven supramolecular metal-organic framework wSMOF-1 has been achieved from intertwined [Ru(tpy)2 ]2+ (tpy=2,2',6',2''-terpyridine) complex M1 and cucurbit[8]uril (CB[8]) in water, where the intermolecular dimers formed by the appended aromatic arms of M1 are encapsulated in CB[8]. wSMOF-1 exhibits ordered pore periodicity in both water and the solid state, as confirmed by a combination of 1 H NMR spectroscopy, UV-vis absorption, isothermal titration calorimetry, dynamic light scattering, small angle X-ray scattering and selected area electron diffraction experiments. The woven framework has a pore aperture of 2.1 nm, which allows for the free access of both secondary and primary alcohols and tert-butyl hydroperoxide (TBHP). Compared with the control molecule [Ru(tpy)2 ]Cl2 , the [Ru(tpy)2 ]2+ unit of wSMOF-1 exhibits a remarkably higher heterogeneous catalysis activity for the oxidation of alcohols by TBHP in n-hexane. For the oxidation of 1-phenylethan-1-ol, the yield of acetophenone was increased from 10 % to 95 %.

Water-Soluble Flexible Organic Frameworks That Include and Deliver Proteins.

Four water-soluble hydrazone-based three-dimensional (3D) flexible organic frameworks FOF-1-4 have been synthesized from a semirigid tetracationic tetraaldehyde and four flexible dihydrazides. 1H NMR spectroscopy indicated the quantitative formation of FOF-1-4 in D2O, while dynamic light scattering experiments revealed that, depending on the concentration, these porous frameworks display hydrodynamic diameters ranging from 50 to 120 nm. The porosity of the frameworks is confirmed by ethanol vapor adsorption experiments of the solid samples as well as the high loading capacity for a 2.3 nm porphyrin guest in water. The new water-soluble frameworks exhibit low cytotoxicity and form inherent pores with diameters of 5.3 or 6.7 nm, allowing rapid inclusion of proteins such as bovine serum albumin and green and orange fluorescent proteins, and efficient delivery of the proteins into normal and cancer cells. Flow cytometric analysis reveals percentages of the delivered cells up to 99.8%.

A tristable [2]rotaxane that is doubly gated by foldamer and azobenzene kinetic barriers.

A hydrogen bonded foldamer unit and an azobenzene unit have been incorporated into the linear component of a tristable [2]rotaxane to give rise to a doubly gated switching system tuned by the folding-defolding of the foldamer unit and the photo-initiated trans-cis isomerization of the azobenzene unit.

Guest-Induced Arylamide Polymer Helicity: Twist-Sense Bias and Solvent-Dependent Helicity Inversion.

A benzene/naphthalene alternately incorporated amide polymer was synthesized and characterized. (1) H NMR spectroscopy, fluorescence, and circular dichroism (CD) experiments indicated that, in chloroform, the polymer could be induced by the chiral l-aspartic acid dianion or one of its derivatives to form a helical tubular conformation with twist-sense bias. CD titration studies showed that the l-aspartic acid dianion (8 equiv.) could lead to a maximum Cotton effect. It was also revealed that the twist-sense bias obeyed the majority rule, and 70 % enantiomeric excess could realize the maximum helicity bias. Adding acetonitrile to the solution of chloroform caused inversion of the guest-induced helicity bias of the polymer.

Bipyridinium Polymers That Dock Tetrathiafulvalene Guests in Water Driven by Donor-Acceptor and Ion Pair Interactions.

Two water-soluble para-xylylene-connected 4,4'-bipyridinium (BIPY(2+) ) polymers have been prepared. UV-Vis absorption, (1) H NMR spectroscopy, and cyclic voltammetry experiments support that in water the BIPY(2+) units in the polymers form stable 1:1 charge-transfer complexes with tetrathiafulvalene (TTF) guests that bear two or four carboxylate groups. These charge-transfer complexes are stabilized by the donor-acceptor interaction between electron-rich TTF and electron-deficient BIPY(2+) units and electrostatic attraction between the dicationic BIPY(2+) units and the anionic carboxylate groups attached to the TTF core. On the basis of UV-Vis experiments, a lower limit to the apparent association constant of the TTF⋅BIPY(2+) complexes of the mixtures, 1.8×10(6) m(-1) , has been estimated in water. Control experiments reveal substantially reduced binding ability of the neutral TTF di- and tetracarboxylic acids to the BIPY(2+) molecules and polymers. Moreover, the stability of the charge-transfer complexes formed by the BIPY(2+) units of the polymers are considerably higher than that of the complexes formed between two monomeric BIPY(2+) controls and the dicarboxylate-TTF donor; this has been attributed to the mutually strengthened electron-deficient nature of the BIPY(2+) units of the polymers due to the electron-withdrawing effect of the BIPY(2+) units.

Synthesis and anticancer activities of a novel class of mono- and di-metallic Pt(II)(salicylaldiminato)(DMSO or Picolino)Cl complexes.

A series of novel Pt(ii) complexes [cis- and trans-Pt(ii)(salicylaldimine)(DMSO)Cl (), trans-Pt(ii)(salicylaldimine)(4-picoline)Cl (), Pt(ii)(salicylaldimine)Cl (), trans- and cis/trans-Pt2(ii)(salicylaldimine)(DMSO)2Cl2 (), trans-Pt2(ii)(salicylaldimine)(4-picoline)2Cl2 () was synthesized and characterized. The structures of -cis, -trans and were determined using a single crystal X-ray analysis. This class of Pt(ii) complexes has been studied for their in vitro cytotoxicity in multiple human cancer cell lines, including breast (MCF-7), liver (HepG2), lung (A549), colon (HCT116) and cervical (Hela) cancers. -trans, and -trans showed significant cytotoxicity to these cancer cells comparable to cisplatin. A time- and dose-dependent MTT assay revealed that these complexes can suppress cell viability and cell proliferation. Mechanistically these complexes induced pro-apoptotic gene expression such as BAX, PUMA and NOXA and thereby enhanced apoptosis. Moreover, PARP cleavage in a dose-dependent manner indicated their cytotoxic effect against cancer cells. Apoptosis of cancer cells occurred through apoptotic pathways as explained by the cytometry analysis. The DNA unwinding properties of these active Pt(ii) complexes were studied by gel electrophoresis using pBR322 plasmid DNA as a target. Changes in the morphology of cancer cells were also observed upon the addition of -trans, and -trans.