47 research outputs found
Hybrid 1D Plasmonic/Photonic Crystals are Responsive to Escherichia Coli
Photonic crystal-based biosensors hold great promise as valid and low-cost
devices for real-time monitoring of a variety of biotargets. Given the high
processability and easiness of read-out even for unskilled operators, these
systems can be highly appealing for the detection of bacterial contaminants in
food and water. Here, we propose a novel hybrid plasmonic/photonic device that
is responsive to Escherichia coli, which is one of the most hazardous
pathogenic bacterium. Our system consists of a thin layer of silver, a metal
that exhibits both a plasmonic behavior and a well-known biocidal activity, on
top of a solution processed 1D photonic crystal. We attribute the
bio-responsivity to the modification of the dielectric properties of the silver
film upon bacterial contamination, an effect that likely stems from the
formation of polarization charges at the Ag/bacterium interface within a sort
of bio-doping mechanism. Interestingly, this triggers a blue-shift in the
photonic response. This work demonstrates that our hybrid plasmonic/photonic
device can be a low-cost and portable platform for the detection of common
contaminants in food and water
Biohybrid Electrospun Membrane for the Filtration of Ketoprofen Drug from Water
A current challenge in materials science and biotechnology is to express a specific and controlled functionality on the large interfacial area of a nanostructured material to create smart biohybrid systems for targeted applications. Here, we report on a biohybrid system featuring poly(vinyl alcohol) as the supporting synthetic polymer and bovine serum albumin as the biofunctional element. The optimal processing conditions to produce these self-standing composite membranes are determined, and the composition and distribution of the bioactive agent within the polymeric matrices are analyzed. A post-processing cross-linking using glutaraldehyde enables this functional membrane to be used as a chemical filter in aqueous environments. By demonstrating that our mats can remove large amounts of ketoprofen from water, we show that the combination of a BSA-induced biofunctionality with a nanostructured fibrous material allows for the development of an efficient biohybrid filtering device for the large and widely used family of nonsteroidal anti-inflammatory drugs (NSAIDs). The crystal structure of the complex between BSA and ketoprofen is determined for the first time and confirms the interaction between the two species
Ultrafast photochromism and bacteriochromism in one dimensional hybrid plasmonic photonic structures
Hybrid plasmonic photonic structures combine the plasmonic response with the
photonic band gap, holding promise for utilization as optical switches and
sensors. Here, we demonstrate the active modulation of the optical response in
such structures with two different external stimuli, e.g. laser pulses and
bacteria. First, we report the fabrication of a miniaturized (5 x 5 mm) indium
tin oxide (ITO) grating employing femtosecond laser micromachining, and we show
the possibility to modulate the photonic band gap in the visible via ultrafast
photoexcitation in the infrared part of the spectrum. Note that the
demonstrated time response in the picosecond range of the spectral modulation
have an industrial relevance. Moreover, we manufacture one-dimensional photonic
crystals consisting of a solution-processed dielectric Bragg stack exposing a
top-layer of bio-active silver. We assign the bacterial responsivity of the
system to polarization charges at the Ag/bacterium interface, giving rise to an
overall blue shift of the photonic band gap.Comment: 7 pages, 4 figure
Hierarchical TiN-Supported TsFDH Nanobiocatalyst for CO2 Reduction to Formate
AbstractThe electrochemical reduction of CO2 to valueâadded products like formate represents a promising technology for the valorization of carbon dioxide. We propose a proofâofâconcept bioelectrochemical system (BES) for the reduction of CO2 to formate. For the first time, our device employs a nanostructured titanium nitride (TiN) support for the immobilization of a formate dehydrogenase (FDH) enzyme. The hierarchical TiN nanostructured support exhibits high surface area and wide pore size distribution, achieving high catalytic loading, and is characterized by higher conductivity than other oxideâbased supports employed for FDHs immobilization. We select the oxygenâtolerant FDH from Thiobacillus sp. KNK65MA (TsFDH) as enzymatic catalyst, which selectively reduces CO2 to formate. We identify an optimal TiN morphology for the enzyme immobilisation through enzymatic assay, reaching a catalyst loading of 59â
ÎŒgâcmâ2 of specificallyâadsorbed TsFDH and achieving a complete saturation of the anchoring sites available on the surface. We evaluate the electrochemical CO2 reduction performance of the TiN/TsFDH system, achieving a remarkable HCOOâ Faradaic efficiency up to 76â%, a maximum formate yield of 44.1â
ÎŒmolâmgâ1FDHâhâ1 and high stability. Our results show the technological feasibility of BES devices employing novel, nanostructured TiNâbased supports, representing an important step in the optimization of these devices
Insight into GEBR\u201032a: Chiral Resolution, Absolute Configuration and Enantiopreference in PDE4D Inhibition
Alzheimer\u2019s disease is the most common type of dementia, affecting millions of people worldwide. One of its main consequences is memory loss, which is related to downstream effectors of cyclic adenosine monophosphate (cAMP). A well\u2010established strategy to avoid cAMP degradation is the inhibition of phosphodiesterase (PDE). In recent years, GEBR\u201032a has been shown to possess selective inhibitory properties against PDE type 4 family members, resulting in an improvement in spatial memory processes without the typical side effects that are usually correlated with this mechanism of action. In this work, we performed the HPLC chiral resolution and absolute configuration assignment of GEBR\u201032a. We developed an efficient analytical and semipreparative chromatographic method exploiting an amylose\u2010based stationary phase, we studied the chiroptical properties of both enantiomers and we assigned their absolute configuration by 1H\u2010NMR (nuclear magnetic resonance). Lastly, we measured the IC50 values of both enantiomers against both the PDE4D catalytic domain and the long PDE4D3 isoform. Results strongly support the notion that GEBR\u201032a inhibits the PDE4D enzyme by interacting with both the catalytic pocket and the regulatory domains
Silane-Mediated Expansion of Domains in Si-Doped Îș-Ga2O3 Epitaxy and its Impact on the In-Plane Electronic Conduction
Unintentionally doped (001)-oriented orthorhombic Îș-Ga2O3 epitaxial films on c-plane sapphire substrates are characterized by the presence of â 10 nm wide columnar rotational domains that can severely inhibit in-plane electronic conduction. Comparing the in- and out-of-plane resistance on well-defined sample geometries, it is experimentally proved that the in-plane resistivity is at least ten times higher than the out-of-plane one. The introduction of silane during metal-organic vapor phase epitaxial growth not only allows for n-type Si extrinsic doping, but also results in the increase of more than one order of magnitude in the domain size (up to â 300 nm) and mobility (highest ” â 10 cm2Vâ1sâ1, with corresponding lowest Ï â 0.2 Ωcm). To qualitatively compare the mean domain dimension in Îș-Ga2O3 epitaxial films, non-destructive experimental procedures are provided based on X-ray diffraction and Raman spectroscopy. The results of this study pave the way to significantly improved in-plane conduction in Îș-Ga2O3 and its possible breakthrough in new generation electronics. The set of cross-linked experimental techniques and corresponding interpretation here proposed can apply to a wide range of material systems that suffer/benefit from domain-related functional properties
Cinque anni di Media Inaf: report 2015-2019
In questo report, inizialmente realizzato in occasione della presentazione dei prodotti di Terza missione per la VQR 2015-2019, sono illustrate la linea editoriale della testata Media Inaf, le principali attivitĂ redazionali e i risultati conseguiti nel quinquennio di riferimento. Per i risultati quantitativi, in particolare, sono esplicitati e descritti gli indicatori utilizzati