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Cellulose is attracting increasing interest as a sustainable technological material, owing to its unique combination of properties, such as abundance in nature, biodegradability, nontoxicity, cost effectiveness, and good mechanical properties. Here, we developed composite thin films based on carboxymethylcellulose (CMC) reinforced with TEMPO-oxidized cellulose nanocrystals (TOCNCs). The strength and stiffness of the CMC/TOCNC nanocomposite film increased by ∼400% and ∼20%, respectively, compared to pure TOCNC films, while preserving the deformation capability of pure CMC films, the latter being less stiff, but more ductile than pure TOCNC films. We demonstrated the tunability of the CMC/TOCNC self-assembly, through Fe3+ complexation, resulting in transparent cross-linked nanocomposite films with enhanced strength (163.5 ± 51.3 MPa) and stiffness (Young's modulus of 14.5 ± 4.0 GPa), with no significant loss in strain at failure (2.8 ± 1.1%). Finally, as applications of newly developed films require durability in realistic operating conditions, which do not involve static forces only, we tested our films against loading–unloading cycles, demonstrating robust and stable performance. By enabling a deeper understanding of the fabrication process and mechanical properties of cellulose-based nanocomposite films, this work expands their potential applications across a broad range of fields, from environment-related processes, such as decontamination, to the biomedical field. [ABSTRACT FROM AUTHOR]

Bifunctional hydroxyl/thiol-functionalized fourth-generation polyamidoamine dendrimer (G4-PAMAM)-encapsulated Au nanoparticle (NP) was synthesized and immobilized on a mixed self-assembled monolayer (SAM)modified gold surface. This modified surface was resistant to nonspecific adsorption of proteins having a wide range of molecular weight and isoelectric points. Part of the dendrimer thiol groups were converted to hydrazide functionalities providing an activated surface available to subsequently immobilize the receptor for developing a sensor surface to immunoaffinity reaction. Herein, the surface plasmon resonance (SPR) detection of insulin was obtained by means of a competitive immunoassay principle. The resulting Au NP dendrimer-modified surface provided an assay with high stability, significantly enhanced sensitivity, and a detection limit for analyzing insulin of 0.5 pM. The SPR detection of insulin was amplified due to the changes in the dielectric properties of the matrixes, occurring upon the biorecognition processes on the sensor surface, through the coupling of the localized plasmon of the NPs with the surface plasmon wave. The developed sensor chip was used to analyze insulin in human serum samples from healthy and diabetic patients. The results showed good correlation to the reference method. The specificity and the improved sensitivity of this biosensing platform could have significant implications for the detection of a wide range of molecules and biomarkers in complex biological media. 10.1021/ac101319k

Au nanoparticles (NPs) are functionalized with thioaniline electropolymerizable groups and (mercaptophenyl)boronic acid. The antibiotic substrates neomycin (NE), kanamycin (KA), and streptomycin (ST) include vicinal diol functionalities and, thus, bind to the boronic acid ligands. The electropolymerization of the functionalized Au NPs in the presence of NE, KA, or ST onto Au surfaces yields bisaniline-cross-linked Au NP composites that, after removal of the ligated antibiotics, provide molecularly imprinted matrixes which reveal high sensitivities toward the sensing of the imprinted antibiotic analytes (detection limits for analyzing NE, KA, and ST correspond to 2.00 [+ or -] 0.21 pM, 1.00 [+ or -] 0.10 pM, and 200 [+ or -] 30 fM, respectively). The antibiotics are sensed by surface plasmon resonance (SPR) spectroscopy, where the coupling between the localized plasmon of the NPs and the surface plasmon wave associated with the Au surface is implemented to amplify the SPR responses. The imprinted Au NP composites are, then, used to analyze the antibiotics in milk samples. 10.1021/ac902944k

An integrated platinum nanoparticles (NPs)/glucose oxidase (GOx) composite film associated with a Au electrode is used to follow the biocatalytic activities of the enzyme. The film is assembled on a Au electrode by the electropolymerization of thioaniline-functionalized Pt NPs and thioaniline-modified GOx. The resulting enzyme/Pt NPs-functionalized electrode stimulates the [O.sub.2] oxidation of glucose to gluconic acid and [H.sub.2][O.sub.2]. The modified electrode is then implemented to follow the activity of the enzyme by the electrochemical monitoring of the generated [H.sub.2][O.sub.2]. The effect of the composition of the Pt NPs/GOx cross-linked nanostructures and the optimal conditions for the preparation of the electrodes are discussed.

Microperoxidase-11 (MP-11) was first soft landed onto the gold surface of a screen-printed electrode. Intact protein deposition was verified by time-of-flight secondary ion mass spectrometry. The coupling of soft landing with electrochemical techniques allowed unique information to be obtained about the deposition features. A full characterization of the direct electron-transfer properties was performed by modeling data obtained from cyclic voltammetry experiments; calculated values of kinetic electron-transfer constant, formal redox potential, and reorganization energy allow us to hypothesize the mechanism involved in soft landing immobilization and demonstrate the different conformation of the enzyme deposited from two different charged species. The strong interaction between MP- 11 and the gold surface and longterm stability of the functionalized electrode characterizes the peculiar features of this procedure, which enhance its power with respect to the existing immobilization procedure and ensure its suitability for those practical applications that could benefit from an unmediated bridgeless bioeletrochemical electron transfer (e.g., biosensor transducers or electrode elements in biofuel cells).

The electropolymerization of thioaniline-functionalized Au nanoparticles (NPs) is performed in the presence of the imprint molecules, picric acid, N,N'-dimethyl-4,4'-bipyridinium, and N,N'-dimethylbipyridinium-4,4'-ethylene dichloride to assemble Au NP composites on Au surfaces. The results provide insight into several routes to control the electrostimulated functions of the Au NP 'sponges' and improve the binding capacity of the Au NP composites.

A bis-aniline-cross-linked Au nanoparticle (NP) composite is electrochemically prepared on a rough Pt film supported on Au electrode, where the electrochemical oxidation of the bis-aniline units to the quinoid state has released protons to the electrolyte solution. The extent of the pH change is controlled by the number of electropolymerization cycles applied to prepare the Au NP composite and these changes are used to reversibly activate and deactivate a C-quadruplex (i-motif)-bridged [Mg.sup.2+]-dependent DNAzyme.