2,2'-Biphenol-based Ultrathin Microporous Nanofilms for Highly Efficient Molecular Sieving Separation.

Organic solvent nanofiltration (OSN) is an emerging membrane separation technology, which urgently requires robust, easily processed, OSN membranes possessing high permeance and small solutes-selectivity to facilitate enhanced industrial uptake. Herein, we describe the use of two 2,2'-biphenol (BIPOL) derivatives to fabricate hyper-crosslinked, microporous polymer nanofilms through IP. Ultra-thin, defect-free polyesteramide/polyester nanofilms (≈5 nm) could be obtained readily due to the relatively large molecular size and ionized nature of the BIPOL monomers retarding the rate of the IP. The enhanced microporosity arises from the hyper-crosslinked network structure and monomer rigidity. Specifically, the amino-BIPOL/PAN membrane exhibits extraordinary permselectivity performances with molecular weight cut-off as low as 233 Da and MeOH permeance of ≈13 LMH/bar. Precise separation of small dye mixtures with similar M.W. based on both their charge and molecular size are achieved.

Fabrication of a Novel Nanofiltration Membrane with Enhanced Performance via Interfacial Polymerization through the Incorporation of a New Zwitterionic Diamine Monomer.

It is known that the polyamide (PA) barrier layer's inherent microstructure and surface physicochemical properties of thin film composite nanofiltration membrane are crucial for its separation performance. Herein, we designed and synthesized a new zwitterionic aromatic diamine monomer 3-(4-(2-((4-aminophenyl)amino)ethyl)morpholino-4-ium)propane-1-sulfonate (PPD-MEPS) through a three steps reaction, and this hydrophilic molecule was incorporated into the active layer to tailor the poly(piperazine-amide)-based nanofiltration membranes with significantly improved water permeability and antifouling properties. As a p-phenylenediamine (PPD) derivative, PPD-MEPS possesses two active amine units, which can react with trimesoyl chloride in the organic phase during the interfacial polymerization reaction process. Thus, the super-hydrophilic zwitterions were not only on the membrane surface but also across the whole PA layer to facilitate water molecule transportation. The successful augmentation of zwitterions into the PA layer was well illustrated by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) results and X-ray photoelectron spectroscopy analysis. With increasing loading content of PPD-MEPS in PIP aqueous solution, the as-fabricated nanofiltration membranes (NFMs) exhibited higher hydrophilicity, increased active layer thickness, and molecular weight cut off. When the zwitterionic monomer reached 60% to PIP for NFM-4, the water permeability went up to 9.82 L m-2 h-1 bar-1, increasing by 45%; meanwhile, the Na2SO4/NaCl selectivity increased from 2.54 to 4.03. In addition, the fouling experiments illustrated that the fouling resistance of the zwitterion-modified NFMs to bovine serum albumin was significantly improved.

Phosphatase-triggered cell-selective release of a Pt(iv)-backboned prodrug-like polymer for an improved therapeutic index.

We describe here the synthesis and cell-selective delivery of a cationic Pt(iv)-backboned prodrug-like polymer P(DSP-DAEP). P(DSP-DAEP) features excellent aqueous solubility, unusually high (44.5%) drug loading, can be rapidly reduced to release the active cisplatin, and is more potent than its small molecular Pt(iv) precursor DSP. P(DSP-DAEP) can be formulated with an oppositely charged methoxyl poly(ethylene glycol)-block-poly(l-phosphotyrosine) (mPEG-b-PpY) to afford a polyion micelle (Pt-PIC) by taking advantage of polyelectrolyte coacervation. Preliminary in vitro cellular uptake and cytotoxicity assays indicate that Pt-PIC exhibits receptor (surface alkaline phosphatase)-dependent uptake and cytotoxicity. Overall, our results suggest a new approach to the improved therapeutic index of platinum-based anticancer drugs via cell-selective delivery.

Targeted delivery of a guanidine-pendant Pt(iv)-backboned poly-prodrug by an anisamide-functionalized polypeptide.

We describe here a novel targeting polyion complex (Tg-PIC) system for the delivery and intracellular release of cisplatin. Briefly, a guanidinium-pendant Pt(iv)-backboned poly-prodrug termed P(DSP-Gu) is prepared with excellent aqueous solubility, high drug-loading and high potency. To enable prolonged circulation and selective cellular internalization, P(DSP-Gu) is complexed with anisamide-end-capped poly(ethylene glycol)-block-poly(l-phosphotyrosine)-block-poly(l-leucine) (AA-PEG-PpY-PLeu) to yield Tg-PIC via electrostatic coacervation. Tg-PIC is stabilized by hydrogen bonding between phosphate and guanidinium, the PEG corona, and the helical poly(l-leucine) segment forming the hydrophobic core. The anisamide group, a high affinity ligand recognizing the sigma (σ) receptors that are overexpressed on many human malignancies including prostate cancer, is incorporated at the surface of the Tg-PIC for active targeting and efficient internalization. In vitro, the Tg-PICs show targeted and efficient internalization into sigma receptor-positive PC3 cells, and can release toxic Pt(ii) species due to the degradation of P(DSP-Gu) under the intracellular reducing conditions. In vivo, the Tg-PICs exhibit superior antitumor efficacy with reduced toxicity. Thus, the system holds considerable promise towards more effective and safe nanomedicine.

Advanced supramolecular polymers constructed by orthogonal self-assembly.

Large aggregates, constructed by linking together monomer building blocks via non-covalent interactions with polymer properties, are regarded as supramolecular polymers. Many kinds of non-covalent interactions, such as metal-ligand coordination, hydrogen bonding, π-π stacking, ionic interaction, and host-guest interaction etc., can be involved in the binding interactions of monomer building blocks, as well as in the modification of the side chain for the construction of variable supramolecular polymers. In this tutorial review, we summarized the reported supramolecular polymers fully- or partially-created from the combination of multiple non-covalent binding interactions, mainly of two kinds, in the orthogonal way.

Formation of polypseudorotaxane networks by cross-linking the quadruple hydrogen bonded linear supramolecular polymers via bisparaquat molecules.

The creation of novel crown ether-paraquat polypseudorotaxane networks, constructed by bisparaquat monomers threading into the cavity of the crown ether units of linear supramolecular polymers that are formed based on the quadruple hydrogen bonded unit ureidopyrimidinone (Upy) in the concentrated solution, is described.

New light on the ring-chain equilibrium of a hydrogen-bonded supramolecular polymer based on a photochromic dithienylethene unit and its energy-transfer properties as a storage material.

A novel, bifunctional, quadruple hydrogen-bonding ureido-pyrimidinone (UPy) unit bridged by photochromic dithienylethene (1) has been synthesized, which affords linear assemblies in solution and undergoes concentration-dependent ring-opening polymerization. The two UPy functional groups of 1 can dimerize intramolecularly to form a cyclic monomer with the two thienyl rings fixed in a parallel conformation, which prohibits its photocyclization. We exploited the photochemical reactivity and resonance difference of the linker of the bis-UPy derivative as well as using the more typical (1)H NMR, DOSY, and Ubbelohde viscometry methods to investigate for the first time the ring-chain polymerization mechanism. Moreover, we fabricated a mixed polymer film with a fluorescent dye noncovalently endcapping the linear photochromic assemblies through quadruple hydrogen bonds, which showed nondestructive fluorescent read-out ability for data storage by fluorescence resonance energy transfer (FRET) from the fluorescent dye to the closed form of the diarylethene.

New linear supramolecular polymers that are driven by the combination of quadruple hydrogen bonding and crown ether-paraquat recognition.

Novel linear supramolecular polymers, based on the combination of two classical binding interactions: the quadruple hydrogen bonding ureidopyrimidinone units and crown ether-paraquat host-guest recognition motifs, have been constructed from two heteroditopic monomers.

Novel organic dyes for efficient dye-sensitized solar cells.

Two novel metal-free organic dyes containing thienothiophene and thiophene segments have been synthesized. Nano-crystalline TiO2 dye-sensitized solar cells were fabricated using these dyes as light-harvesting sensitizers, and a high solar energy-to-electricity conversion efficiency of 6.23% was achieved.