Synthesis of Bis(indolyl)methanes Using Hyper-Cross-Linked Polyaromatic Spheres Decorated with Bromomethyl Groups as Efficient and Recyclable Catalysts

Highly uniform and hyper-cross-linked polyphenanthrene and polypyrene microspheres were synthesized by Friedel–Crafts bromomethylation of phenanthrene (Phn) and pyrene (Py) in the presence of zinc bromide as a catalyst, followed by self-polymerization of bromomethylated Phn and Py. The resultant 3-D carbon microspheres consisting of micro-, meso-, and macropores bear peripheral unreacted bromomethyl groups, which are directly utilized as catalysts to efficiently promote the electrophilic substitution reaction of indoles with aldehydes to yield a variety of bis­(indolyl)­methanes. The important features of this catalysis are easy catalyst synthesis, high product yields, environmental benignity, short reaction time, broad substrate scope, use of nontoxic solvents, and recyclability

Hyper-Cross-Linked Polypyrene Spheres Functionalized with 3‑Aminophenylboronic Acid for the Electrochemical Detection of Diols

A sensor for the determination of diols using 3-aminophenylboronic acid (APBA)-functionalized hyper-cross-linked polypyrene (PPy) (APBA@PPy) is presented. The uniform (∼1 μm in diameter) and highly porous (628 m² g^–1 in specific surface area) PPy spheres are fabricated via a one-pot protocol that consists of ZnBr₂-catalyzed alkylation of pyrene, a subsequent cross-linking reaction, and concomitant self-assembly. The PPy spheres formed within a few minutes at mild conditions are featured by an excellent structural integrity and inertness to organic solvents. Thus, the APBA@PPy composites (∼1 μm in diameter; 458 m² g^–1 in specific surface area) are prepared simply by substituting unreacted bromomethyl groups on the surface of PPy spheres for APBA. The APBA@PPy composites are successfully applied for the electrochemical sensing of d-glucose and dopamine. A dye displacement assay is also performed using alizarin red dye conjugated to boronic acid in glucose buffer solution

Easy Synthesis of Hierarchical Carbon Spheres with Superior Capacitive Performance in Supercapacitors

An easy template-free approach to the fabrication of pure carbon microspheres has been achieved via direct pyrolysis of as-prepared polyaromatic hydrocarbons including polynaphthalene and polypyrene. The polyaromatics were synthesized from aromatic hydrocarbons (AHCs) using anhydrous zinc chloride as the Friedel–Crafts catalyst and chloromethyl methyl ether as a cross-linker. The experimental results show that the methylene bridges between phenyl rings generate a hierarchical porous polyaromatic precursor to form three-dimensionally (3D) interconnected micro-, meso-, and macroporous networks during carbonization. These hierarchical porous carbon aggregates of spherical carbon spheres exhibit faster ion transport/diffusion behavior and increased surface area usage in electric double-layer capacitors. Furthermore, micropores are present in the 3D interconnected network inside the cross-linked AHC-based carbon microspheres, thus imparting an exceptionally large, electrochemically accessible surface area for charge accumulation

Fabrication of Microspheres via Solvent Volatization Induced Aggregation of Self-Assembled Nanomicellar Structures and Their Use as a pH-Dependent Drug Release System

A series of oleamide derivatives, (C₁₈H₃₄NO)₂(CH₂)_<i>n</i> [<i>n</i> = 2 (<b>1a</b>), 3 (<b>1b</b>), 4 (<b>1c</b>), or 6 (<b>1d</b>); C₁₈H₃₄NO = oleic amide fragment] and (C₁₈H₃₄NO)­(CH₂)₆NH₂ (<b>2</b>), have been synthesized and their self-assembly is investigated in ethanol/water media. Self-assembly of <b>1a</b> and <b>1b</b> in ethanol/water (1/0.1 <i>v</i>/<i>v</i>) solution (5 mg mL^–1) yields microspheres (MSs) with the average diameter ∼10 μm via a gradual temperature reduction and solvent volatilization process. Under the same self-assembly conditions, microrods (average diameter ∼6 μm and several tens of micrometers in length), micronecklace-like, and shape-irregular microparticles are formed from the self-assembly of <b>1c</b>, <b>1d</b>, and <b>2</b>, respectively. The kinetics of evolution for their self-assemblies by dynamic light scattering technique and in situ observation by optical microscopy reveals that the microstructures formation is from a well-behaved aggregation of nanoscale micelles induced by solvent volatilization. The FT–IR and temperature–dependent ¹H–NMR spectra demonstrate the hydrogen bonding force and π–π stacking, which drove the self-assembly of all oleamide derivatives in ethanol/water. Among the fabricated microstructures, the MSs from <b>1a</b> exhibit the best dispersity, which thus have been used as a scaffold for the in vitro release of doxorubicin. The results demonstrate a pH-sensitive release process, enhanced release specifically at low pH 5.2

Self-Assembly of Morphology-Tunable Architectures from Tetraarylmethane Derivatives for Targeted Drug Delivery

Tetraarylmethane compounds consisting of two pyrogallol and two aniline units, namely, Ar₂CAr′₂ {Ar = 3,4,5-C₆H₂(OH)₃ and Ar′ = 3,5-R₂-4-C₆H₂NH₂ [R = Me (<b>1</b>), <i>i</i>Pr (<b>2</b>)]} exhibit excellent self-assembly behavior. Compound <b>1</b> yields size-tunable hollow nanospheres (HNSs) with a narrow size distribution, and <b>2</b> yields various morphologies ranging from microtubules to microrods <i>via</i> self-assembly induced by hydrogen bonding and π–π stacking interactions. On the basis of the experimental results, a plausible mechanism for morphology tunability was proposed. As a means of utilizing the self-assembled HNSs for targeting controlled drug delivery, folic acid (FA) and rhodamine 6G (Rh6G) were grafted onto compound <b>1</b> to yield the FA–Rh6G–<b>1</b> complex. The HNSs fabricated with FA–Rh6G–<b>1</b> showed low cytotoxicity against human embryonic kidney 293T cells and CT26 colon carcinoma cells and good doxorubicin (DOX) loading capacity (9.6 wt %). The FA receptor-mediated endocytosis of FA–Rh6G–<b>1</b> HNSs examined by using a confocal laser scanning microscope and a flow cytometer revealed that the uptake of FA–Rh6G–<b>1</b> HNSs into CT26 cells was induced by FA receptor-mediated endocytosis. <i>In vitro</i> drug delivery tests showed that the DOX molecules were released from the resulting HNSs in a sustainable and pH-dependent manner, demonstrating a potential application for HNSs in targeted drug delivery for cancer therapy

A Hyper-cross-linked Polynaphthalene Semiconductor with Excellent Visible-Light Photocatalytic Performance in the Degradation of Organic Dyes

Hyper-cross-linked polynaphthalene nanoparticles (PNNs) capable of catalyzing the degradation of organic pollutants upon exposure to visible light have been developed. The nascent and metal-free PNNs with a porous structure, high specific surface area, and narrow bandgap are chemically and thermally stable in the catalytic system, which make it promising as a kind of excellent photocatalytic material compared to conventional photocatalysts. The photocatalytic activity of the as-obtained PNNs exhibits remarkable photocatalytic performance for the degradation of rhodamine B (RhB) and methyl blue (MB) under the irradiation of visible light. The easy preparation, high catalytic activity, and recyclability of the PNNs open new opportunities in the visible-light-promoted degradation of organic pollutants

Efficient, Solvent-Free, Multicomponent Method for Organic-Base-Catalyzed Synthesis of β‑Phosphonomalonates

An efficient, one-pot, di-<i>n</i>-butylamine-catalyzed, three-component synthesis of β-phosphonomalonates has been developed. A wide range of substrates, including aromatic and fused aromatic aldehydes, were condensed with enolizable C–H activated compounds and dialkylphosphites to give the desired products in excellent yields. This method provides an eco-friendly alternative approach to rapid construction of a diversity-oriented library of β-phosphonomalonates

Phospholipid End-Capped Bioreducible Polyurea Micelles as a Potential Platform for Intracellular Drug Delivery of Doxorubicin in Tumor Cells

Bioreducible polymeric nanocarriers bearing disulfide bonds have been widely used for intracellular therapeutic delivery, since they are quickly sliced or reduced in the reductive milieu of cytosol. Incorporation of hydrophobic phospholipid analogues to polymers improves the biocompatibility by reducing the protein adsorption and platelet adhesion on the cell membranes. In this study, we have developed a series of bioreducible polyureas (PUs) bearing disulfide linkages in their backbone and phospholipid moieties in their chain ends. The reducible PUs exhibit interesting self-assembly behavior and controlled release profiles at intracellular mimic conditions. The self-assembled hybrid nanocarriers with an average diameter of about 110 nm efficiently encapsulated the model anticancer drug doxorubicin (Dox). The <i>in vitro</i> Dox release profile demonstrated a good glutathione (GSH)-responsive release of Dox at 10 mM GSH. An <i>in vitro</i> cell viability assay was also performed with various cell lines. The antitumor activity tests using HCT15 and HCT116 cancer cells showed that Dox-loaded nanocarriers bearing disulfide linkages induced significantly higher cytotoxicity in cancer cells than those without disulfide linkages. Hence, the PU nanocarriers bearing disulfide linkers and α,ω-phospholipid moieties have a promising potential to trigger the drug into the intracellular compartment of cancer cells

Dual Stimuli-Responsive Poly(<i>N</i>‑isopropylacrylamide)‑<i>b</i>‑​poly(l‑histidine) Chimeric Materials for the Controlled Delivery of Doxorubicin into Liver Carcinoma

A series of dual stimuli responsive synthetic polymer bioconjugate chimeric materials, poly­(<i>N</i>-isopropylacrylamide)₅₅-<i>block</i>-poly­(l-histidine)_<i>n</i> [p­(NIPAM)₅₅-<i>b</i>-p­(His)_<i>n</i>] (<i>n</i> = 50, 75, 100, 125), have been synthesized by employing reversible addition–fragmentation chain transfer polymerization of NIPAM, followed by ring–opening polymerization of α-amino acid <i>N</i>-carboxyanhydrides. The dual stimuli responsive properties of the resulting biocompatiable and membrenolytic p­(NIPAM)₅₅-<i>b</i>-p­(His)_<i>n</i> polymers are investigated for their use as a stimuli responsive drug carrier for tumor targeting. Highly uniform self-assembled micelles (∼55 nm) fabricated by p­(NIPAM)₅₅-<i>b</i>-p­(His)_<i>n</i> polymers display sharp thermal and pH responses in aqueous media. An anticancer drug, doxorubicin (Dox), is effectively encapsulated in the micelles and the controlled Dox release is investigated in different temperature and pH conditions. Antitumor effect of the released Dox is also assessed using the HepG2 human hepatocellular carcinoma cell lines. Dox molecules released from the [p­(NIPAM)₅₅-<i>b</i>-p­(His)_<i>n</i>] micelles remain biologically active and have stimuli responsive capability to kill cancer cells. The self-assembling ability of these hybrid materials into uniform micelles and their efficiency to encapsulate Dox makes them a promising drug carrier to cancer cells. The new chimeric materials thus display tunable properties that can make them useful for a molecular switching device and controlled drug delivery applications needing responses to temperature and pH for the improvement of cancer chemotherapy

Dual Stimuli-Responsive Vesicular Nanospheres Fabricated by Lipopolymer Hybrids for Tumor-Targeted Photodynamic Therapy

Smart delivery system of photosensitizer chlorin e6 (Ce6) has been developed for targeted photodynamic therapy (PDT). Simple self-assemblies of the mixtures comprising soybean lecithin derived phosphatidylcholine (PC), phosphatidylethanolamine-poly­(l-histidine)₄₀ (PE–p­(His)₄₀), and folic acid (FA) conjugated phosphatidylethanolamine-poly­(<i>N</i>-isopropylacrylamide)₄₀ (PE–p­(NIPAM)₄₀–FA) in different ratios yield smart nanospheres characterized by (i) stable and uniform particle size (∼100 nm), (ii) positive surface charge, (iii) high hydrophobic drug (Ce6) loading efficiency up to 45%, (iv) covalently linked targeting moiety, (v) low cytotoxicity, and (vi) smartness showing p­(His) block oriented pH and p­(NIPAM) oriented temperature responsiveness. The Ce6-encapsulated vesicular nanospheres (Ce6@VNS) were used to confirm the efficiency of cellular uptake, intracellular distribution, and phototoxicity against KB tumor cells compared to free Ce6 at different temperature and pH conditions. The Ce6@VNS system showed significant photodynamic therapeutic efficiency on KB cells than free Ce6. A receptor-mediated inhibition study proved the site-specific delivery of Ce6 in targeted tumor cells