The key role of 3-glycidoxypropyltrimethoxysilane sol–gel precursor in the development of wearable sensors for health monitoring

Textiles represent an attractive class of materials for realizing wearable biosensors. Electronic textiles, or smart textiles, describe the convergence of electronics and textiles into fabrics, which are able to sense, compute, communicate, and actuate. As many different electronic systems can be connected to any clothing, a wearable system becomes more versatile, and the user can change its look depending on environmental changes and individual preference. In this review, we want to explain how it is possible to develop the sensing component of a wearable sensor by sol–gel method based on the use of opportune organofunctional trialkoxysilane precursors, such as 3-glycidoxypropyltrimethoxysilane. Results show that the halochromic dyestuffs are completely entrapped in the sol–gel coatings, both through chemical and physical interactions with the textile fabric. Moreover, a certain washing fastness was observed. Sensor films show excellent reproducibility, reversibility, and short response times, with dynamic ranges from pH 4.4–6.0 (Methyl Red), pH 6.0–7.0 (Nitrazine Yellow), and pH 4.5–8.3 (Litmus), respectively.

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Synthesis,characterization, X-ray structure and preliminary in vitro antitumor activity of the nitrosyl complex fac-[RuCl3(NO)(dppf)], dppf = 1,1′-bis(diphenylphosphine)ferrocene

The reaction of RuCl₃NO · 2H₂O with stoichiometric amount of dppf, 1,1′-bis(diphenylphosphino)ferrocene, afforded the new neutral nitrosyl complex fac-[RuCl₃(NO)(dppf)] which was characterized by spectroscopical, electrochemical and X-ray crystallography techniques as well as elemental analysis. The ν_NO band in the IR spectrum is at 1860 cm⁻¹ (CH₂Cl₂ solution) and in the cyclic voltammogram an irreversible wave was observed at −1.35 V, both are characteristics of a nitrosonium (NO⁺) character for the coordinated NO. Additionally, preliminary in vitro antitumor activity against the MDA-MB-231 breast tumor cell line was carried out for the new complex. The initial results indicated an important activity for fac-[RuCl₃(NO)(dppf)] (IC₅₀ = 10 ± 3 μM ). The complex has a higher cytotoxicity than the precursor complex RuCl₃NO · 2H₂O, the free dppf ligand as well as the reference metallodrug cisplatin.     

The electrochemistry of gold in acetonitrile solutions containing thiocyanate ions

Gold dissolves anodically in acetonitrile solutions containing dissolved NaSCN, at 25°C. The reaction yields Au(I) and Au(III) complex ion species which can be cathodically electroplated. The voltammetric experiments indicate that the anodic dissolution is preceded by a partial surface saturation with the intermediate initially discharged, followed by a diffusion controlled process which depends on the SCN^? ion concentration. The electrochemical behaviour of the anodic and cathodic processes is comparable to that of gold in aqueous solutions containing Au-complex ions.     

Mechanism of the photochemical substitution of 6-membered ring monoazaaromatic compounds by methanol in neutral and HCl acidified medium

6-Membered ring monoazaaromatic compounds such as pyridine, quinoline, 4-methylquinoline, isoquinoline and 9-phenylacridine are converted to the corresponding semiquinone radicals when irradiated in methanol acidified with HCl, ether or neutral methanol. In a neutral medium the hydrogen photoabstraction occurs from an nπ^* excited state by a monophotonic process, but in methanol acidified with HCl, the photoreaction corresponds to a biphotonic process. In this case the photoreaction involves an electron transfer from methanol to a protonated upper excited triplet state of the solute (Scheme 2, path 2).     

Assessment of semi-automated catecholamine assay by HPLC: Choice of reverse phase C18 or cation-exchange columns

Summary HPLC with electrochemical detection is useful in the assay of catecholamines in biological samples. Two types of chromatographic column are currently employed by most investigators: reverse phase C-18 (RPC-18) or strong cation-exchange (SCX) columns. Our aim was to evaluate the specificity, sensitivity and reproducibility of plasma and urinary catecholamine assay by these two columns. Our study indicates that both columns give very good performance for clinical purposes but sensitivity, precision at low concentration and specificity seem to be better with ion-exchange columns which are therefore preferred at the present time.     

Comparative study between the polysaccharide-based chiralcel OJ and chiralcel OD CSPSs in chromatographic enantioseparation of imidazole analogues of fluoxetine and miconazole

The enantiomeric separation of a series of imidazole analogues of Fluoxetine and Miconazole endowed with potent antifungal activity was performed using cellulose tris(4-methylbenzoate) (Chiralcel OJ) and cellulose tris(3,5-dimethylphenylcarbamate) (Chiralcel OD) as chiral stationary phases. Binary mixtures of n-hexane and alcohol as well as pure alcohols (ethanol or 2-propanol) were used as eluents. The enantiomer elution order was monitored by chiroptical detectors based on on-line optical rotation and circular dichroism measurements. For some of the compounds studied very high enantioseparation factor values (alpha > 7) on Chiralcel OJ CSP were observed. In order to study the chiroptical characteristics of the two most biologically active compounds, chromatographic resolutions were carried out on a semipreparative scale. Assignment of the absolute configuration was empirically established by comparing the CD spectra of the separated enantiomers with those obtained from the enantiomers of Miconazole.     

Interactions with aromatic rings in chemical and biological recognition

Intermolecular interactions involving aromatic rings are key processes in both chemical and biological recognition. Their understanding is essential for rational drug design and lead optimization in medicinal chemistry. Different approaches-biological studies, molecular recognition studies with artificial receptors, crystallographic database mining, gas-phase studies, and theoretical calculations-are pursued to generate a profound understanding of the structural and energetic parameters of individual recognition modes involving aromatic rings. This review attempts to combine and summarize the knowledge gained from these investigations. The review focuses mainly on examples with biological relevance since one of its aims it to enhance the knowledge of molecular recognition forces that is essential for drug development.