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The efficacy of immunotherapy can be undermined by the development of an immune response against a drug/antibody mediated by anti-drug antibodies (ADAs) in treated patients. We present the first label-free EGOFET immunosensor that integrates a biological drug, Nivolumab (Opdivo©), as a specific recognition moiety to quantitatively and selectively detect ADAs against the drug. The limit of detection is 100 fM. This demonstration is a prelude to the detection of ADAs in a clinical setting in the treatment of different pathologies, and it also enables rapid screening of biological drugs for immunogenicity.

Monoatomic nanosheets can form 2-dimensional channels with tunable chemical properties, for ion storage and filtering applications. Here, we demonstrate transport of K + , Na + , and Li + cations and F - and Cl - anions on the centimeter scale in graphene oxide membranes (GOMs), triggered by an electric bias. Besides ion transport, the GOM channels foster also the aggregation of the selected ions in salt crystals, whose composition is not the same as that of the pristine salt present in solution, highlighting the difference between the chemical environment in the 2D channels and in bulk solutions., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

It is well known that amphiphilic cationic β-cyclodextrins (amβCDs) form nanovesicles able to release their cargo in aqueous solution upon applying different stimuli. In addition they can be selectively positioned onto substrates by unconventional soft lithography. This makes them a powerful tool for designing environments where different cues can be externally supplied to the cells helping to achieve good control of their fate. Lithographically controlled wetting (LCW) of amβCD nanovesicles loaded with fluorescein isothiocyanate (FITC), amβCD/FITC, has been used here to fabricate geometrically functionalized surfaces, thus achieving multiscale control of the cell environment. The amβCD functionalization was strongly influenced by the surface energy of the underlying substrates that, according to their hydrophobicity, orient the amβCD in a different way, thus "offering" different portions to the cells. The structure of the pattern was characterized both over large scales exploiting the FITC fluorescence and at the nanoscale by atomic force microscopy. Cell guidance and aCD/FITC cell internalization were demonstrated in human neuroblastoma SHSY5Y cells., Competing Interests: The authors declare no conflicts of interest., (This journal is © The Royal Society of Chemistry.)

The controlled release of cell differentiating agents is crucial in many aspects of regenerative medicine. Here we propose the use of hybrid calcite single crystals as micro-carriers for the controlled and localized release of retinoic acid, which is entrapped within the crystalline lattice. The release of retinoic acid occurs only in the proximity of stem cells, upon dissolution of the calcite hybrid crystals that are dispersed in the fibrin scaffold. These hybrid crystals provide a sustained dosage of the entrapped agent. The environment provided by this composite scaffold enables differentiation towards neuronal cells that form a three-dimensional neuronal network.

Scanning tunnelling microscopy (STM) studies have found stripe-like domains on gold nanoparticles (NPs) coated with certain binary mixtures of ligand molecules. The majority of these NPs' properties have been investigated for particles in solvents. Yet, most STM studies are for NPs in a dry state. Images of the same particles in air and liquid have not been obtained yet. In this work, a judicious choice of ligand molecules led to NPs with close-to-ideal STM imaging conditions in air and in 1-phenyloctane (PO). Large datasets under both conditions were acquired and rapidly evaluated through power spectral density (PSD) analysis. The result is a quantitative comparison of stripe-like domains in air and PO on the same NPs. PSD analysis determines a characteristic length-scale for these domains of ~1.0 nm in air and in PO showing persistence of striped domains in these two media. A length scale of ~0.7 nm for homoligand NPs was found.

The structure of small gold nanoclusters (around 2.5 nm) deposited on different silica-on-silicon (SiOx/Si) substrates is investigated using several characterization techniques (AFM, XRD, EXAFS and GISAXS). The grain morphology and the surface roughness of the deposited gold cluster layers are determined by AFM. The in-plane GISAXS intensity is modelled in order to obtain information about the cluster size and the characteristic length scale of the surface roughness. The surface morphology of the deposited clusters depends on whether the native defect-rich (n-SiOx/Si) or the defect-poor substrate obtained by thermal treatment (t-SiO2/Si) is used. Gold clusters show a stronger tendency to aggregate when deposited on n-SiOx/Si, resulting in films characterized by a larger grain dimension (around 20 nm) and by a higher surface roughness (up to 5 nm). The more noticeable cluster aggregation on n-SiOx/Si substrates is explained in terms of metal-support interaction mediated by the defects located on the surface of the native silica substrate. Evidence of metal-support interaction is provided by EXAFS, demonstrating the existence of an Au-O distance for clusters deposited on n-SiOx/Si that is not found on t-SiO2/Si.

There is a quest for electronic biosensors operated in water for biomedical applications and environmental monitoring. Water is an aggressive medium for standard electronics materials and devices due to its strong polarizability and electrochemical activity. Thick dielectric encapsulation provides necessary stability while it damps the sensitivity of the device to sensing events occurring in the aqueous environment. Organic electronics provides materials that exhibit stable electronic conduction in direct contact with water combined with other desirable properties like mechanical softness, biocompatibility and processability onto flexible substrates. In this review, we introduce an emerging class of organic transistors, in which the current across the organic film is gated by the electric field of the Debye-Helmholtz layer. We discuss the device physics, the sensing mechanism and the relevant electrochemical processes. Applications of water-gated transistors range from the sensing of biologically relevant molecules like DNA, proteins or hormones to non-invasive recording and stimulation of electrical activity of neurons. Materials chemistry is crucial to control properties of electrically active films and to allow the introduction of specific chemical functionalities and receptors at sensing interfaces of the device.

Electronic transducers of neuronal cellular activity are important devices in neuroscience and neurology. Organic field-effect transistors (OFETs) offer tailored surface chemistry, mechanical flexibility, and high sensitivity to electrostatic potential changes at device interfaces. These properties make them attractive for interfacing electronics with neural cells and performing extracellular recordings and stimulation of neuronal network activity. In this work we operate pentacene ultra-thin film (9 nm thick) transistors with a liquid gate both as transducers and electrical stimulators of neuronal network activity. These devices are highly sensitive to small potential changes in cell medium and exhibit sufficient stability under standard cell culture conditions for nine days. We show that murine neural stem cells can be adhered on top of functional devices without the need for an additional layer of cell-adhesive molecules, and then differentiated into neuronal networks. OFET response is monitored during the different phases of the neuronal differentiation process up to nine days. Only when stem cells are differentiated into neurons, it is possible to measure electrical signals in the OFET current following the stimulation. Due to the large sensing area of our device, which accommodates from hundreds to thousands of interconnected neurons, the OFET electrical signals arise from the collective electrophysiological response of the neuronal population. The maximum extracellular potential change in the cleft region adjacent to the transistor surface amounts to 350 μV. This demonstrates that pentacene ultra-thin film OFETs enable good cellular adhesion and efficient coupling of the ionic currents at the biological-organic semiconductor interface with the OFET current.

Alkanethiol Self-Assembly Monolayers (SAMs) were investigated by means of BiModal Atomic Force Microscopy. Morphological and mechanical properties show a parabolic trend vs. the chain length n, which is ascribed to the disorder at the SAMs/Au interface. This explains the trend of charge injection across SAMs in organic field effect transistors., (This journal is © The Royal Society of Chemistry 2011)

Single molecule magnets (SMM) are a class of molecules exhibiting magnetic properties similar to those observed in conventional bulk magnets, but of molecular origin. SMMs have been proposed as potential candidates for several technological applications that require highly controlled thin films and patterns. Here we present an overview of the most important approaches for thin film growth and micro(nano)-patterning of SMM, giving special attention to Mn(12) based molecules. We present both conventional approaches to thin film growth (Langmuir-Blodgett, chemical approach, dip and dry, laser evaporation), patterning (micro-contact printing, deposition on patterned surface, moulding of homogeneous films) and new methods specifically developed for SMM (lithographically controlled wetting, lithographically controlled de-mixing).