coronal protein signatures and biological impact of silver nanoparticles synthesized with different natural polymers as capping agents.

Biopolymer-capped particles, sodium alginate-, gelatin- and reconstituted silk fibroin-capped nanosilver (AgNPs), were synthesized with an intention to study, simultaneously, their and haemocompatibility, one of the major safety factors in biomedical applications. Solid state characterization showed formation of spherical nanoparticles with 5 to 30 nm primary sizes (transmission electron microscopy) and X-ray photoelectron spectroscopy analysis of particles confirmed silver bonding with the biopolymer moieties. The degree of aggregation of the biopolymer-capped AgNPs in the synthesis medium (ultrapure water) is relatively low, with comparable hydrodynamic size with those of the control citrate-stabilized NPs, and remained relatively unchanged even after 6 weeks.

Understanding the performance of a paper-based UV exposure sensor: The photodegradation mechanism of brilliant blue FCF in the presence of TiO photocatalysts in both the solid state and solution.

Rationale: The decolouration of brilliant blue FCF by the action of titanium dioxide (TiO ) under ultraviolet (UV) exposure has been recently reported as the basis of a paper-based sensor for monitoring UV sun exposure. The mechanism of brilliant blue FCF photodegradation in the presence of the photocatalyst and the resulting photoproducts are thus far unknown.

Methods: The UV-initiated photodegradation of brilliant blue FCF in the presence of TiO for both the aqueous and the solid state was investigated.

Micropatterning of porous silicon Bragg reflectors with poly(ethylene glycol) to fabricate cell microarrays: Towards single cell sensing.

The work presented here describes the development of an optical label-free biosensor based on a porous silicon (PSi) Bragg reflector to study heterogeneity in single cells. Photolithographic patterning of a poly(ethylene glycol) (PEG) hydrogel with a photoinitiator was employed on RGD peptide-modified PSi to create micropatterns with cell adhesive and cell repellent areas. Macrophage J774 cells were incubated to form cell microarrays and single cell arrays.

Reversible Thermoresponsive Plasmonic Core-Satellite Nanostructures That Exhibit Both Expansion and Contraction (UCST and LCST).

The assembly of sophisticated gold nanoparticle constructs where thermoresponsive core-satellite nanostructures are created and the satellites are close enough to the core for strong surface plasmon resonance coupling to occur, has begun to be developed. The linker between the core and the satellites being a thermoresponsive polymer means that a dispersion of these nanostructures will show temperature-dependent optical properties as the distance between the core and the satellites changes. Unlike previous related thermoresponsive core-satellite systems that undergo a single thermoresponsive transition, herein a polymer system with dual thermoresponsive transitions (block copolymer with both lower critical solution temperature and upper critical solution temperature) is employed as a linker that modulates the gap distance between the "core" and "satellites" in response to the temperature.

Thermoresponsive plasmonic core-satellite nanostructures with reversible, temperature sensitive optical properties.

Herein is described a facile method for the assembly of plasmonic gold nanoparticles into smart plasmonic core-satellite nanostructures that allow for the dynamic and reversible tuning of the localised surface plasmon resonance using temperature. This smart system takes advantage of the thermoresponsive polymer linker that modulates the gap distance between the core and satellites in response to the temperature, resulting in the tuning of the surface plasmon coupling and resultant optical shift. It permits optical shifts over a wide wavelength range and reversible control of the optical properties by altering the temperature, which may allow these systems to become candidates for temperature sensitive nanosensors.

Can single molecule localization microscopy be used to map closely spaced RGD nanodomains?

Cells sense and respond to nanoscale variations in the distribution of ligands to adhesion receptors. This makes single molecule localization microscopy (SMLM) an attractive tool to map the distribution of ligands on nanopatterned surfaces. We explore the use of SMLM spatial cluster analysis to detect nanodomains of the cell adhesion-stimulating tripeptide arginine-glycine-aspartic acid (RGD).

Simple Method for Tuning the Optical Properties of Thermoresponsive Plasmonic Nanogels.

We report a straightforward way for forming and tuning the optical properties of thermally responsive plasmonic nanogels. Upon functionalization, a small red shift (2-3 nm) of the pNIPAM@AuNPs was observed due to changes in the refractive index surrounding the AuNP. By adding thermoresponsive poly--isopropylacrylamide (pNIPAM) into the pNIPAM@AuNP, its optical response was significantly increased.

A versatile method for the preparation of carbon-rhodium hybrid catalysts on graphene and carbon black.

Strategies for combining the selectivity and efficiency of homogeneous organometallic catalysts with the versatility of heterogeneous catalysts are urgently needed. Herein a direct and modular methodology is presented that provides rapid access to well-defined carbon-rhodium hybrid catalysts. A pre-synthesized Rh(i) complex containing a carbene-triazole ligand was found to be stable for direct immobilization onto unactivated graphene, carbon black and glassy carbon electrodes.

Reversible gating of smart plasmonic molecular traps using thermoresponsive polymers for single-molecule detection.

Single-molecule surface-enhanced Raman spectroscopy (SERS) has attracted increasing interest for chemical and biochemical sensing. Many conventional substrates have a broad distribution of SERS enhancements, which compromise reproducibility and result in slow response times for single-molecule detection. Here we report a smart plasmonic sensor that can reversibly trap a single molecule at hotspots for rapid single-molecule detection.

Heat-treated stainless steel felt as scalable anode material for bioelectrochemical systems.

This work reports a simple and scalable method to convert stainless steel (SS) felt into an effective anode for bioelectrochemical systems (BESs) by means of heat treatment. X-ray photoelectron spectroscopy and cyclic voltammetry elucidated that the heat treatment generated an iron oxide rich layer on the SS felt surface. The iron oxide layer dramatically enhanced the electroactive biofilm formation on SS felt surface in BESs.

Polymersomes prepared from thermoresponsive fluorescent protein-polymer bioconjugates: capture of and report on drug and protein payloads.

Polymersomes provide a good platform for targeted drug delivery and the creation of complex (bio)catalytically active systems for research in synthetic biology. To realize these applications requires both spatial control over the encapsulation components in these polymersomes and a means to report where the components are in the polymersomes. To address these twin challenges, we synthesized the protein-polymer bioconjugate PNIPAM-b-amilFP497 composed of thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) and a green-fluorescent protein variant (amilFP497).

Synthesis and high-throughput processing of polymeric hydrogels for 3D cell culture.

3D cell cultures have drawn a large amount of interest in the scientific community with their ability to closely mimic physiological conditions. Hydrogels have been used extensively in the development of extracellular matrix (ECM) mimics for 3D cell culture. Compounds such as collagen and fibrin are commonly used to synthesize natural ECM mimics; however they suffer from batch-to-batch variation.

Flame oxidation of stainless steel felt enhances anodic biofilm formation and current output in bioelectrochemical systems.

Stainless steel (SS) can be an attractive material to create large electrodes for microbial bioelectrochemical systems (BESs), due to its low cost and high conductivity. However, poor biocompatibility limits its successful application today. Here we report a simple and effective method to make SS electrodes biocompatible by means of flame oxidation.

Chemical patterning on preformed porous silicon photonic crystals: towards multiplex detection of protease activity at precise positions†Electronic supplementary information (ESI) available: SEM images, XPS result and more optical reflectivity data. See DOI: 10.1039/c4tb00281dClick here for additional data file.

Porous silicon (PSi) rugate filters modified with alkyne-terminated monolayers were chemically patterned using a combination of photolithography of photoresist and click chemistry. Two chemical functionalities were obtained by conjugating, click reactions, ethylene glycol moieties containing two different terminal groups to discrete areas towards the exterior of a PSi rugate filter. The patterning of biological species to the functionalized surface was demonstrated through the conjugation of fluorescein isothiocyanate labelled bovine serum albumin (FITC-BSA).

Stimuli-responsive functionalized mesoporous silica nanoparticles for drug release in response to various biological stimuli.

A silica-based mesoporous nanosphere (MSN) controlled-release drug delivery system has been synthesized and characterized. The system uses l-cysteine derivatized gold nanoparticles (AuNPs), bound to the MSNs using Cu as a bridging ion. The AuNPs serve as removable caps that hinder the release of drug molecules inside the amino functionalized MSN mesoporous framework.

Light-induced organic monolayer modification of iodinated carbon electrodes.

We report the modification of carbon electrodes formed from pyrolyzed photoresist films (PPF) via plasma iodination followed by the organic monolayer modification of these surfaces. The iodinated surfaces were characterized using cyclic voltammetry, atomic force microscopy, and X-ray photoelectron spectroscopy to enable the optimization of the iodination while preserving the stability and smoothness of the carbon surface. Subsequently, the C-I surface was further modified with molecules that possess an alkene or alkyne at one end through light activation with low energy (visible range λ 514 nm).

High-order multiblock copolymers via iterative Cu(0)-mediated radical polymerizations (SET-LRP): toward biological precision.

We report a new approach for the facile synthesis of high-order multiblock copolymers comprising very short blocks. The approach entails sequential addition of different monomers via an iterative single electron transfer-living radical polymerization technique, allowing nearly perfect control of the copolymer microstructure. It is possible to synthesize high-order multiblock copolymers with unprecedented control, i.

Post-functionalization of ATRP polymers using both thiol/ene and thiol/disulfide exchange chemistry.

In this communication, we report on a new route to the functionalization of ATRP polymers exploiting their halide end-groups, which were converted successfully into reactive disulfide end-groups, using sodium methanethiosulfonate. The resultant disulfide-terminated polymers could then be reacted with different functional thiols to yield functional polymers exploiting either thiol/disulfide exchange chemistry or thiol/ene "click" reactions.

High fidelity vinyl terminated polymers by combining RAFT and cobalt catalytic chain transfer (CCT) polymerization methods.

In this work, we combine reversible addition fragmentation transfer polymerization (RAFT) with cobalt catalytic chain transfer (CCT) to obtain omega-unsaturated polymers with relatively low polydispersity values.