Peptide Brush Polymers for Efficient Delivery of a Gene Editing Protein to Stem Cells

The scarcity of effective means to deliver functional proteins to living cells is a central problem in biotechnology and medicine. Herein, we report the efficient delivery of an active DNA‐modifying enzyme to human stem cells through high‐density cell penetrating peptide brush polymers. Cre recombinase is mixed with a fluorophore‐tagged polymer carrier and then applied directly to induced pluripotent stem cells or HEK293T cells. This results in efficient delivery of Cre protein as measured by activation of a genomically integrated Cre‐mediated recombination reporter. We observed that brush polymer formulations utilizing cell penetrating peptides promoted Cre delivery but oligopeptides alone or oligopeptides displayed on nanoparticles did not. Overall, we report the efficient delivery of a genome‐modifying enzyme to stem cells that may be generalizable to other, difficult‐to‐transduce cell types.     

Plasma‐Activated Substrate with a Tropoelastin Anchor for the Maintenance and Delivery of Multipotent Adult Progenitor Cells

Conventional wound therapy utilizes wound coverage to prevent infection, trauma, and fluid and thermal loss. However, this approach is often inadequate for large and/or chronic wounds, which require active intervention via therapeutic cells to promote healing. To address this need, a patch which delivers multipotent adult progenitor cells (MAPCs) is developed. Medical‐grade polyurethane (PU) films are modified using plasma immersion ion implantation (PIII), which creates a radical‐rich layer capable of rapidly and covalently attaching biomolecules. It is demonstrated that a short treatment duration of 400 s maximizes surface activation and wettability, minimizes reduction in gas permeability, and preserves the hydrolytic resistance of the PU film. The reactivity of PIII‐treated PU is utilized to immobilize the extracellular matrix protein tropoelastin in a functional conformation that stably withstands medical‐grade ethylene oxide sterilization. The PIII‐treated tropoelastin‐functionalized patch significantly promotes MAPC adhesion and proliferation over standard PU, while fully maintaining cell phenotype. Topical application of the MAPC‐seeded patch transfers cells to a human skin model, while undelivered MAPCs repopulate the patch surface for subsequent cell transfer. The potential of this new wound patch as a reservoir for the sustained delivery of therapeutic MAPCs and cell‐secreted factors for large and/or non‐healing wounds is indicated in the findings.     

Hexayne Amphiphiles and Bolaamphiphiles

Oligoynes with two or more conjugated carbon–carbon triple bonds are useful precursors for carbon-rich nanomaterials. However, their range of applications has so far been severely limited by the challenging syntheses, particularly in the case of oligoynes with functional groups. Here, we report a universal synthetic approach towards both symmetric and unsymmetric, functionalized hexaynes through the use of a modified Eglinton–Galbraith coupling and a sacrificial building block. We demonstrate the versatility of this approach by preparing hexaynes functionalized with phosphonic acid, carboxylic acid, ammonium, or thiol head groups, which serve as neutral, cationogenic, or anionogenic interfacially active groups. We show that these hexaynes are carbon-rich amphiphiles or bolaamphiphiles that self-assemble at liquid–liquid interfaces, on solid surfaces, as well as in aqueous media.     

Determination of cobalt by catalytic-adsorptive differential pulse voltammetry

A novel method is described for the determination of cobalt(II) by differential pulse voltammetry, based on accumulation of a cobalt complex, [CoSCNNO]⁺, on a hanging mercury drop electrode, followed by measurement of the catalytic current of the adsorbed complex. The effects of various experimental parameters on the catalytic current were investigated. The current was found to be linear for 0.3 nM to 100 nM Co, with a detection limit of 70 pM (4.1 ng l⁻¹) and a relative standard deviation of 1.6% for 50 nM Co (n = 25). The developed method showed considerable selectivity against nickel and zinc. A possible mechanism of the reduction process is proposed.     

Isolation and identification of surface-bound acetone enolate on Ni(111)

A surface-bound acetone enolate species has been synthesized on Ni(111) between 260 and 340 K by two different routes catalyzed by surface Ni and O atoms: deprotonation of acetone and deacetylation of acetylacetone. The reaction pathways and surface species have been identified using reflection absorption infrared spectroscopy (RAIRS) in combination with isotopic substitution and density functional theory (DFT) calculations. Acetone enolate exhibits characteristic vibrational absorption bands at 1260, 1353, and 1545 cm-1 arising from mixed modes that involve CC stretching, CH3 bending, and CO stretching. This work conclusively proves the existence of stable acetone enolate species on a metal single-crystal surface and provides its first detailed characterization.     

Predicting the whiteness index of cotton fabric with a least squares model

Cellulose - The textile bleaching process that involves hot hydrogen peroxide (H2O2) solution is commonly practised in cotton fabric manufacture. The purpose of the bleaching process is to remove...     

Energy transfer through heterogeneous dyes‐substituted fluorene‐containing alternating copolymers and their dual‐emission properties in the films

We report synthesis of the modified fluorene polymers tethered to the heterogeneous types of the fluorescent dyes at the cardo carbon for obtaining the dual‐emissive solid materials. A series of the alternating fluorene copolymers modified with pyrene or 9,10‐diphenylanthracene and BODIPY at the cardo carbon based on the red‐emissive donor–acceptor structure were prepared, and their characteristics were examined. From the measurements of the optical properties, the energy transfer efficiencies were evaluated. In summary, variable energy transfer efficiencies were observed between the side chains and from the side chain to the main chain. It was indicated that the energy transfer efficiencies were strongly depended on the types of the energy donor and the detection conditions as such in the solution or film. Furthermore, it was found that the cardo fluorene units can contribute to the suppression of the energy transfer in the condensed state. Finally, the dual‐emissive polymers were obtained in the film states. This is the first example, to the best of our knowledge, not only to offer systematic information on the energy transfer between the dye molecules and the polymer main‐chains via the cardo structure but also to demonstrate the polymer‐based optical materials with the dual‐emission properties. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2026–2035     

Characterization of Capsicum annuum Recombinant α- and β-Tubulin

There are several conditions which might modulate polymerization to produce polymers having normal lattice structure. In the absence of 1 mM MgCl₂ the assembly was reduced by 36% in Capsicum annuum tubulin (CAnm tubulin). There was no significant difference in the final assembly formation in the presence of 5% to 10% glycerol. However, nucleation rate was slow and apparent study state was achieved lately in the presence of 10% glycerol. Taxol at 100 μM concentration increased 23% tubulin assembly. One millimolar CaCl₂, ≥1% dimethyl sulfoxide (DMSO) and physiologically low temperature reduced CAnm tubulin assembly. A value of 0.089 mg/ml was obtained as critical concentration for polymerization. Benomyl significantly reduced the number of cysteine residues accessible to 5,5’-dithiobis-(2-nitrobenzoic acid); there were 4.77?±?0.21 and 3.49?±?0.35 residues accessible per tubulin dimer in the presence of 50 and 100 μM benomyl respectively.