Molecular schizophrenics as sensors and actuators

‘Sensornets’ are large-scale distributed sensing networks comprised of many small sensing devices equipped with memory, processors, and short-range wireless communications capabilities.1 These devices, assembled from building blocks known as ‘Motes’ can gather and share sensor data from multiple locations through in-built wireless communications capabilities. The vision of incorporating chemical and biological sensing dimensions into these platforms is very appealing, and the potential applications in areas critical to society are truly revolutionary.2 For example, the environment; sensors monitoring air and water quality will be able to provide early warning of pollution events arising at industrial plants, landfill sites, reservoirs, and water distribution systems at remote locations. The crucial missing part in this scenario is the gateway through which these worlds will communicate; how can the digital world sense and respond to changes in the real world? Unfortunately, it would appear from the lack of field deployable devices in commercial production that attempts to integrate molecular sensor science into portable devices have failed to bear the fruits promised; this problem is what we call ‘the chemo-/ bio-sensing paradox’.3 In this work, we shall discuss how sensors and sensing systems are likely to develop in the coming years, with a particular focus on the critical importance of new concepts in fundamental materials science to the realisation of these futuristic chemo-/bio-sensing systems. This work focuses on the fundamental challenges, such as the ability to control the characteristics and behaviour of polymers and fluids, and processes occurring at solid-liquid interfaces. We will highlight the key role that stimuli-responsive materials can play in producing new “adaptive” materials capable of exhibiting dramatic changes in properties by external stimuli, such as, photon irradiation.4 In particular, the photochromic processes of spirobenzopyran, figure 1. These materials have the potential to revolutionise the way we design chemical and biological sensing systems

A multiswitchable poly(terthiophene) bearing a spiropyran functionality: understanding photo and electrochemical control

An electroactive nitrospiropyran-substituted polyterthiophene, 2-(3,3′′-dimethylindoline-6′-nitrobenzospiropyranyl)ethyl 4,4′′-didecyloxy-2,2′:5′,2′′-terthiophene-3′-acetate, has been synthesized for the first time. The spiropyran, incorporated into the polymer backbone by covalent attachment to the alkoxyterthiophene monomer units, leads to multiple coloured states as a result of both electrochemical isomerization of the spiropyran moiety to merocyanine forms as well as electrochemical oxidation of the polyterthiophene backbone and the merocyanine substituents. While electrochemical polymerization of the terthiophene monomer could occurs without the apparent oxidation of the spiropyran, the subsequent electrochemistry is complex and clearly involves this substituent. In order to understand this complex behaviour, the first detailed electrochemical study of the oxidation of the precursor spiropyran, 1-(2-hydroxyethyl)-3,3-dimethylindoline-6’-nitrobenzospiropyran, was undertaken, showing that, in solution, an irreversible electrochemical oxidation of the spiropyran occurs leading to reversible redox behaviour of at least two merocyanine isomers. With these insights, an extensive electrochemical and spectroelectrochemical study of the nitrospiropyran-substituted polyterthiophene films reveals an initial irreversible electrochemical oxidative ring opening of the spiropyran to oxidized merocyanine. Subsequent reduction and cyclic voltammetry of the resulting nitromerocyanine-substituted polyterthiophene film gives rise to the formation of both merocyanine π-dimers or oligomers and π-radical cation dimers, between polymer chains. Although merocyanine formation is not electrochemically reversible, the spiropyran can be photochemically regenerated, at least in part, through irradiation with visible light. SEM and AFM images support the conclusion that the bulky spiropyran substituent is electrochemically isomerizes to the planar merocyanine moiety affording a smoother polymer film. The conductivity of the freestanding polymer film was found to be 0.4 S cm-1

Strengthening Community Schools Through University Partnerships

Given the mounting call for academic achievement gains in America’s public schools— particularly urban schools labeled “failing”—the need for community engagement to tackle a host of underlying social challenges warrants the resources of the nation’s colleges and universities (Harkavy & Hartley, 2009). Because colleges and universities are often underutilized anchors of resources in communities, coordinated alignment of K-12 and higher education goals can create a seamless pipeline of educational attainment for communities challenged to produce high academic achievement. Higher education’s engagement with community schools further helps to address the whole child and their families in K-12 education by expanding the opportunities for the students and community to access necessary support services. Drawing upon experiences of Indiana University Purdue University Indianapolis (IUPUI) and collaboration with its adjacent neighborhoods, this article illustrates the transformative and relevant impact of university and community engagement, as well as new pedagogical approaches to teaching, learning, and training. This article reflects upon the experiences of IUPUI and nearby George Washington Community High School as it can uniquely serve as a roadmap for other school community/university partnerships that are interested in embarking upon a similar education reform path

“Signal Corps Intelligence Agency Activities” on Page 18 in the “Quadrennial Report of the Chief Signal Officer, US Army, May 1951-April 1955.”

This is a brief organizational history of a small special-purpose intelligence agency focused on signal equipment used by foreign armies and on the organization and activities of analogous organizations to the US Army Signal Corps in foreign armies. In addition, the Signal Corps Intelligence Agency had been tasked with producing intelligence concerning the Soviet-Bloc civilian power and communications networks. In the 1950s, the Chief Signal Officer was the head of the US Army Signal Corps which was one of the US Army Technical Services. The Technical Services were bureaus which supplied the army with weapons and equipment, organized and trained special-purpose military units, provided the army with technical services, and managed the careers of officers commissioned in the corresponding branches. The Signal Corps provided communications and photographic services to the army

“Signal Corps Intelligence Agency Activities” on Page 18 in the “Quadrennial Report of the Chief Signal Officer, US Army, May 1951-April 1955.”

This is a brief organizational history of a small special-purpose intelligence agency focused on signal equipment used by foreign armies and on the organization and activities of analogous organizations to the US Army Signal Corps in foreign armies. In addition, the Signal Corps Intelligence Agency had been tasked with producing intelligence concerning the Soviet-Bloc civilian power and communications networks. In the 1950s, the Chief Signal Officer was the head of the US Army Signal Corps which was one of the US Army Technical Services. The Technical Services were bureaus which supplied the army with weapons and equipment, organized and trained special-purpose military units, provided the army with technical services, and managed the careers of officers commissioned in the corresponding branches. The Signal Corps provided communications and photographic services to the army

A merocyanine-based conductive polymer

We report the first example of a conducting polymer with a merocyanine incorporated into the polymer backbone by electropolymerisation of a spiropyran moiety covalently linked between two alkoxythiophene units. Utilising the known metal coordination capabilities of merocyanines, introduction of cobalt ions into the electropolymerisation led to an enhancement of the conductivity, morphology and optical properties of the polymer films

In vitro growth and differentiation of primary myoblasts on thiophene based conducting polymers

Polythiophenes are attractive candidate polymers for use in synthetic cell scaffolds as they are amenable to modification of functional groups as a means by which to increase biocompatibility. In the current study we analysed the physical properties and response of primary myoblasts to three thiophene polymers synthesized from either a basic bithiophene monomer or from one of two different thiophene monomers with alkoxy functional groups. In addition, the effect of the dopants pTS- and ClO4 - was investigated. In general, it was found that pTS- doped polymers were significantly smoother and tended to be more hydrophilic than their ClO 4 - doped counterparts, demonstrating that the choice of dopant significantly affects the polythiophene physical properties. These properties had a significant effect on the response of primary myoblasts to the polymer surfaces; LDH activity measured from cells harvested at 24 and 48 h post-seeding revealed significant differences between numbers of cells attaching to the different thiophene polymers, whilst all of the polymers equally supported cell doubling over the 48 h period. Differences in morphology were also observed, with reduced cell spreading observed on polymers with alkoxy groups. In addition, significant differences were seen in the polymers\u27 ability to support myoblast fusion. In general pTS- doped polymers were better able to support fusion than their ClO4 - doped counterparts. These studies demonstrate that modification of thiophene polymers can be used to promote specific cellular response (e.g. proliferation over differentiation) without the use of biological agents. 2013 The Royal Society of Chemistry

Physicochemical study of spiropyran-terthiophene derivatives: photochemistry and thermodynamics

The photochemistry and thermodynamics of two terthiophene (TTh) derivatives bearing benzospiropyran (BSP) moieties, 1-(3,3’’-dimethylindoline-6’-nitrobenzospiropyranyl)-2-ethyl 4,4’’-didecyloxy-2,2’:5’,2’’-terthiophene-3’-acetate (BSP-2) and 1-(3,3’’-dimethylindoline-6’-nitrobenzospiropyranyl)-2-10 ethyl 4,4’’-didecyloxy-2,2’:5’,2’’-terthiophene-3’-carboxylate (BSP-3), differing only by a single methylene spacer unit, have been studied. The kinetics of photogeneration of the equivalent merocyanine (MC) isomers (MC-2 and MC-3, respectively), the isomerisation properties of MC-2 and MC-3, and the thermodynamic parameters have been studied in cetonitrile, and compared to the parent, non-TThfunctionalised, benzospiropyran derivative, BSP-1. Despite the close structural similarity of BSP-2 and 15 BSP-3, their physicochemical properties were found to differ significantly; examples include activation energies (Ea(MC-2) = 75.05 KJ mol-1, Ea(MC-3) = 100.39 kJ mol-1) and entropies of activation (S‡ MC-2 = - 43.38 J K-1 mol-1, S‡ MC-3 = 37.78 J K-1 mol-1) for the thermal relaxation from MC to BSP, with the MC-3 value much closer to the unmodified MC-1 value (46.48 J K -1 mol-1) for this latter quantity. The thermal relaxation kinetics and solvatochromic behaviour of the derivatives in a range of solvents of 20 differing polarity (ethanol, dichloromethane, acetone, toluene and diethyl ether) are also presented. Differences in the estimated values of these thermodynamic and kinetic parameters are discussed with reference to the molecular structure of the derivatives