Microfluidic behaviour of perfluoropolyether fluids in poly(dimethylsiloxane) micro-channels

Two different perfluoropolyether-based fluids, namely the unfunctionalized GALDEN SV90® and the dihydroxy derivative FOMBLIN Z-DOL® 2000 were employed as liquid samples in a poly(dimethylsiloxane) (PDMS) microfluidic setup, fabricated by soft-lithography techniques. The results of our investigation were compared with the behaviour of the low viscosity and high-fragility polyurethane structural adhesive (NOA72®), that is well known as an excellent material for the fabrication of sub-micrometer structures by soft-lithography techniques, and whose structural elastic properties inside restricted geometric systems have been recently investigated

Modification of micro-channel filling flow by poly(dimethylsiloxane) surface functionalization with fluorine—Substituted aminonaphthols

Microfluidics based on the capillarity-induced filling of elastomeric channels by a suitable liquid or solution represents a useful route for realizing portable diagnostic devices designed without additional mechanical or electrical micropumps. In this study, an elastomeric mold made of poly(dimethylsiloxane) (PDMS), containing relief patterns placed in intimate contact with a silicon substrate, is utilized to create a continuous network of rectangular micro-channels for the motion of water fluid. The immobilization on activated PDMS surface of suitable functional molecules such as hydrophilic and hydrophobic fluorine-containing aminonaphthols, obtained through a straightforward and versatile synthetic procedure, allowed us to modulate PDMS surface properties depending on the structural characteristics of the employed derivative. In this context, the incorporation of fluorine groups is important for improving biocompatibility of the resulting device, providing surfaces that could be chemically and biologically inert as well as resistant to surface adhesion phenomena. The functionalization from liquid phase of PDMS replicas, involving a covalent derivatization via silanization reaction of the above mentioned compounds to an oxidized PDMS surface, resulted in a successful modification of microfluidic motion of water in rectangular capillaries, moreover contact angle values evidence also how wettability of PDMS films could be modulated, with the fluorinated aminonaphthols fuctionalized PDMS exhibiting higher contact angles. (C) 2009 Elsevier B.V. All rights reserved

Synthesis of Poly(acrylic acid) Nanogels and Application in Loading and Release of an Oligothiophene Fluorophore and Its Bovine Serum Albumin Conjugate

Nanometer-sized poly(acrylic acid) (PAA) hydrogels were synthesized by emulsion polymerization of methyl acrylate and subsequent acid hydrolysis, and their pH-dependent swelling behaviour was studied by dynamic light scattering. To determine the suitability of PAA nanogels as pH-sensitive carriers for biomedical applications, loading and release of an oligothiophene fluorophore and its albumin conjugate onto the PAA nanogels were investigated as a function of pH by absorption and photoluminescence measurements. it was observed that loading and release processes of both the oligothiophene and its conjugate could be controlled by changing pH of their solutions

Smart surfaces for pH controlled cell staining

In this work, novel smart surfaces for in situ cell staining were realized by covalent attachment of pH-responsive microgels on platforms dedicated to microfluidics for lab-on-chip. The poly(methacrylic acid) microgels were firstly synthesized in solution and then covalently immobilized on a glass surface. As they preserve their pH-sensitive nature after the covalent immobilization, microgels were loaded with an oligothiophene-conjugated anti-human CD4 monoclonal antibody, and finally incubated with a Jurkat T-cell suspension. The physiological pH of the extracellular environment induced the pH-triggered release of the labeled anti-CD4 antibodies and the selective staining of the CD4-positive subpopulations within the Jurkat cell suspension. The realization of this type of smart surface for the encapsulation of specific monoclonal antibodies and their release in an on-demand way should have an enormous potential in developing fully integrated platforms for cell analysis

Surfactant-free synthesis of pure anatase TiO2 nanorods suitable for dye-sensitized solar cells

A non-aqueous, solvothermal method was applied to the synthesis of TiO(2) nanorods in pure anatase crystal phase using Ti(IV)-isopropoxide. The use of benzyl alcohol as both solvent and reactant was investigated in combination with the addition of acetic acid to the reaction mixture. Various values of the AcOH : Ti(OiPr)(4) molar ratio were realized in the synthesis and tested in order to obtain a significant dimensional and morphological control over the resulting TiO(2) nanostructures, as well as to devise a simple and scalable synthetic protocol. On the basis of the experimental results, a substantially modified version of the well-established "benzyl alcohol route' was then designed and developed. X-ray diffractometry and transmission electron microscopy revealed that monodisperse anatase nanorods having a length of about 13-17 nm and a diameter of 5 nm can be obtained when AcOH and Ti(OiPr)(4) are reacted in comparable proportions. Investigation of the characteristic parameters of dye-sensitized solar cells fabricated using the synthesized nanorods as photoanode revealed a power conversion efficiency of about 7.5% corresponding to an improvement of 28% with respect to a commercial spheroidal nanotitania (P25) based reference device

Sub-nanomolar detection of biogenic amines by SERS effect induced by hairy Janus silver nanoparticles

Surface enhanced Raman scattering (SERS) is largely used as a transduction method for analytes detection in liquid and vapor phase. In particular, SERS effect was promoted by a plethora of different metal and semiconducting nanoparticles (NPs) and silver and gold nanoparticles appear particularly suitable for this application. Nevertheless, silver nanoparticles intrinsic propensity to aggregate in large clusters reduces the possibility to use naked nanoparticles in SERS applications, for this reason they are usually functionalized with organic molecules. This approach inhibits the aggregation process but, on the other hand, reduces the surficial area of the NPs able to interact with the analyte molecules. In the present work, we propose a simple method to obtain surficial anisotropic Janus silver nanoparticles: octadecylamine was used to stabilize the nanoparticles and to promote the deposition of the silver nanoparticles on a solid substrate. The AgNPs/octadecylamine nanostructures showed the typical “hairy” Janus morphology and a strong SERS effect was observed when two biogenic amines, i. e. 2-phenylethylamine and tyramine, were fluxed on the solid film. SERS phenomenon was studied as a function both of the chemical structure of the fluxed amine and of the distance between the aromatic moiety and the nanoparticle allowing to propose the AgNPs/octadecylamine Janus nanoparticles as an active layer for the detection of phenylethylamine and tyramine in picomolar concentration

Novel Preparation Method of TiO2-Nanorod-Based Photoelectrodes for Dye-Sensitized Solar Cells with Improved Light-Harvesting Efficiency

We present a novel, facile, and cost-effective method to prepare highly transparent mesoporous films made by anatase TiO2 nanorods that have been synthesized by a single-step solvothermal process. Such nanorods have been conveniently used as prepared-without completely removing the residual organics-to obtain suitable screen-printable paste by means of the use of proper polymeric binders. This method has been successfully implemented to fabricate highly efficient nanorod-based photoelectrodes for dye-sensitized solar cells. They showed an increment of the overall quantum conversion efficiency comprised between 34% and 58% with respect to cells based oil commercial P25 titanium dioxide nanoparticles. In particular, a maximum photocurrent density and solar conversion efficiency of 16.9 mA/cm(2) and 7.9% have been obtained, respectively

Selective reactions on the tips of colloidal semiconductor nanorods

A strategy to access several types of Au-tipped dumbbell-like nanocrystal heterostructures is presented, which involves the selective oxidation of either PbSe or CdTe sacrificial domains, initially grown on CdSe and CdS nanorods, with a Au(III) : surfactant complex. The formation of gold patches is supported by TEM, XRD and elemental analysis. This approach has allowed us to grow Au domains onto specific locations of anisotropically shaped nanocrystals for which direct metal deposition is unfeasible, as for the case of CdS nanorods. We believe that this strategy may be of general utility to create other types of complex colloidal nanoheterostructures, provided that a suitable sacrificial material can be grown on top of the starting nanocrystal seeds

Sonication-Assisted Production of Fosetyl-Al Nanocrystals: Investigation of Human Toxicity and In Vitro Antibacterial Efficacy against Xylella Fastidiosa

none10Recently, there is a growing demand in sustainable phytopathogens control research. Nanotechnology provides several tools such as new pesticides formulations, antibacterial nanomaterials and smart delivery systems. Metal nano-oxides and different biopolymers have been exploited in order to develop nanopesticides which can offer a targeted solution minimizing side effects on environment and human health. This work proposed a nanotechnological approach to obtain a new formulation of systemic fungicide fosetyl-Al employing ultrasonication assisted production of water dispersible nanocrystals. Moreover, chitosan was applicated as a coating agent aiming a synergistic antimicrobial effect between biopolymer and fungicide. Fosetyl-Al nanocrystals have been characterized by morphological and physical-chemical analysis. Nanotoxicological investigation was carried out on human keratinocytes cells through cells viability test and ultrastructural analysis. In vitro planktonic growth, biofilm production and agar dilution assays have been conducted on twoXylella fastidiosasubspecies. Fosetyl-Al nanocrystals resulted very stable over time and less toxic respect to conventional formulation. Finally, chitosan-based fosetyl-Al nanocrystals showed an interesting antibacterial activity againstXylella fastidiosasubsp.paucaandXylella fastidiosasubsp.fastidiosa.Regione Puglia, Deliberazione della Giunta Regionale n. 1410 del 12/06/2015 “Linee guida per il parco della ricerca e sperimentazione finalizzata alla prevenzione e al contenimento del complesso del disseccamento rapido dell’olivo (CODIRO)” Project FATA- “Trattamenti fitoterapici innovativi a base di vettori di chitosano” MIPAAFT, Project Oli.Di.X.I.It-“OLIvicoltura e Difesa da Xylella fastidiosa e da Insetti vettori in Italia”, D.M. 23773 del 6/09/2017.openFrancesca Baldassarre; Giuseppe Tatulli; Viviana Vergaro; Stefania Mariano; Valeria Scala; Concetta Nobile; Nicoletta Pucci; Luciana Dini; Stefania Loreti; Giuseppe CiccarellaBaldassarre, Francesca; Tatulli, Giuseppe; Vergaro, Viviana; Mariano, Stefania; Scala, Valeria; Nobile, Concetta; Pucci, Nicoletta; Dini, Luciana; Loreti, Stefania; Ciccarella, Giusepp

Low-Intensity Light-Responsive Anticancer Activity of Platinum(II) Complex Nanocolloids on 2D and 3D In Vitro Cancer Cell Model

none8This study aimed to evaluate the therapeutic efficacy of low-intensity visible light responsive nanocolloids of a Pt-based drug using a 2D and three-dimensional (3D) in vitro cancer cell model. Biocompatible and biodegradable polymeric nanocolloids, obtained using the ultrasonication method coupled with Layer by Layer technology, were characterized in terms of size (100 ± 20 nm), physical stability, drug loading (78%), and photoactivation through spectroscopy studies. The in vitro biological effects were assessed in terms of efficacy, apoptosis induction, and DNA-Pt adducts formation. Biological experiments were performed both in dark and under visible light irradiation conditions, exploiting the complex photochemical properties. The light-stimuli responsive nanoformulation gave a significant enhancement in drug bioactivity. This allowed us to achieve satisfying results by using nanomolar drug concentration (50 nM), which was ineffective in darkness condition. Furthermore, our nanocolloids were validated in 3D in vitro spheroids using confocal microscopy and cytofluorimetric assay to compare their behavior on culture in 2D monolayers. The obtained results confirmed that these nanocolloids are promising tools for delivering Pt-based drugs.This study was supported by “Tecnopolo di Nanotecnologia e Fotonica per la Medicina di Precisione” (TECNOMED)-FISR/MIUR-CNR: delibera CIPE n.3449 del 7/08/2017, CUP: B83B17000010001; “Tecnopolo per la Medicina di precisione” (TecnoMed Puglia) - Regione Puglia: DGR n.2117 del 21/11/2018, CUP: B84I18000540002.openViviana Vergaro; Francesca Baldassarre; Federica De Castro; Danilo Migoni; Maria Michela Dell’Anna; Piero Mastrorilli; Francesco Paolo Fanizzi; Giuseppe CiccarellaVergaro, Viviana; Baldassarre, Francesca; DE CASTRO, Federica; Danilo, Migoni; Michela Dell’Anna, Maria; Mastrorilli, Piero; Fanizzi, Francesco Paolo; Ciccarella, Giusepp