Step-Growth Cyclo-Oligomerization for the Preparation of Di- and Tetrafunctionalized Pillar[5]arenes

The preparation of complex functionalized pillar­[<i>n</i>]­arenes (PA­[<i>n</i>]­s) is challenging by one-pot cocyclization or selective deprotection method. We developed a step-growth cyclo-oligomerization method to synthesize functionalized PA[5]­s. Dimers, trimers, and tetramers were synthesized and characterized. With this new method, we were able to prepare three di- and tetrafunctionalized PA[5]­s. By using a multistep synthetic strategy, the chance to form constitutional isomers and other by-products was reduced. Therefore, complex tetrafunctionalized PA[5]­s were prepared with improved yield

Step-Growth Cyclo-Oligomerization for the Preparation of Di- and Tetrafunctionalized Pillar[5]arenes

The preparation of complex functionalized pillar­[<i>n</i>]­arenes (PA­[<i>n</i>]­s) is challenging by one-pot cocyclization or selective deprotection method. We developed a step-growth cyclo-oligomerization method to synthesize functionalized PA[5]­s. Dimers, trimers, and tetramers were synthesized and characterized. With this new method, we were able to prepare three di- and tetrafunctionalized PA[5]­s. By using a multistep synthetic strategy, the chance to form constitutional isomers and other by-products was reduced. Therefore, complex tetrafunctionalized PA[5]­s were prepared with improved yield

Acyclic Cucurbit[<i>n</i>]uril Molecular Containers Selectively Solubilize Single-Walled Carbon Nanotubes in Water

Making single-walled carbon nanotubes (SWNTs) soluble in water is a challenging first step to use their remarkable electronic and optical properties in a variety of applications. We report that acyclic cucurbit­[<i>n</i>]­uril molecular containers <b>1</b> and <b>2</b> selectively solubilize small-diameter and low chiral angle SWNTs. The selectivity is tunable by increasing the concentration of the molecular containers or by adjusting the ionic strength of the solution. Even at a concentration 1000 times lower than typically required for surfactants, the molecular containers render SWNTs soluble in water. Molecular mechanics simulations suggest that these C-shaped acyclic molecules complex the SWNTs such that a large portion of nanotube sidewalls are exposed to the external environment. These “naked” nanotubes fluoresce upon patching the exposed surface with sodium dodecylbenzene sulfonate

Improved Solubility and Bioactivity of Camptothecin Family Antitumor Drugs with Supramolecular Encapsulation by Water-Soluble Pillar[6]arene

Water-soluble pillar[6]­arene (WP6) was used to solubilize camptothecin family antitumor drugs. In the presence of WP6, the solubility of camptothecin (CPT) and 10-hydroxycamptothecin (HCPT) was enhanced by 380 and 40 times, respectively. The solubility enhancement is proved to be the result of the host–guest encapsulation by WP6. WP6 has a low cytotoxicity against normal MC 3T3-E1 cells, whereas the bioactivity of CPT and HCPT is substantially improved as a result of the solubility enhancement

Influence of primer concentrations.

<p>Emulsion PCR amplification was carried out for 35 cycles; the number of templates was 0.01 pmol/ml; the concentration of Taq DNA polymerase was 0.125 U/µl; and the annealing temperature was 65°C.</p

Simulation diagrams of emulsion PCR amplification of a random DNA library.

<p>Different compartment contained different templates marked with different colors, and some compartment are empty.</p

Conventional PCR amplification of a DNA random library versus emulsion PCR.

<p>PAGE electropherograms of PCR reaction mixtures for amplification of a random DNA library with conventional PCR (A) and emulsion PCR (C). Microfluidic chip electrophoresis electropherograms of PCR reaction mixtures for amplification of a random DNA library with conventional PCR (B) and emulsion PCR (D). Dynamics of product and by-product concentrations in conventional PCR and emusion PCR (E). Conventional PCR amplification was performed with cycles ranging from 10 to 32; the template concentration was 0.01 pmol/ml; the primer concentration was 0.4 µmol/L; and the concentration of Taq DNA polymerase was 0.05 U/µl. Emulsion PCR amplification was performed with cycles ranging from 10 to 40; the template concentration was 0.01 pmol/ml; the primer concentration was 0.4 µmol/L; and the concentration of Taq DNA polymerase was 0.125 U/µl.</p

Influence of the annealing temperature.

<p>The concentration of the dsDNA products and by-products was obtained from microfluidic chip electrophoresis. Emulsion PCR amplification was carried out for 35 cycles; the number of template was 0.01 pmol/ml; the primer concentration was 0.4 µmol/L; and the concentration of Taq DNA polymerase was 0.125 U/µl.</p

Reductively Responsive Hydrogel Nanoparticles with Uniform Size, Shape, and Tunable Composition for Systemic siRNA Delivery <i>in Vivo</i>

To achieve the great potential of siRNA based gene therapy, safe and efficient systemic delivery <i>in vivo</i> is essential. Here we report reductively responsive hydrogel nanoparticles with highly uniform size and shape for systemic siRNA delivery <i>in vivo</i>. “Blank” hydrogel nanoparticles with high aspect ratio were prepared using continuous particle fabrication based on PRINT (particle replication in nonwetting templates). Subsequently, siRNA was conjugated to “blank” nanoparticles via a disulfide linker with a high loading ratio of up to 18 wt %, followed by surface modification to enhance transfection. This fabrication process could be easily scaled up to prepare large quantity of hydrogel nanoparticles. By controlling hydrogel composition, surface modification, and siRNA loading ratio, siRNA conjugated nanoparticles were highly tunable to achieve high transfection efficiency <i>in vitro</i>. FVII-siRNA conjugated nanoparticles were further stabilized with surface coating for <i>in vivo</i> siRNA delivery to liver hepatocytes, and successful gene silencing was demonstrated at both mRNA and protein levels

Influence of DNA polymerase concentrations.

<p>Emulsion PCR amplification was carried out for 35 cycles; the number of templates was 0.01 pmol/ml; the primer concentration was 0.4 µmol/L; and the annealing temperature was 65°C.</p