Design and construction of a distributed sensor NET for biotelemetric monitoring of brain energetic metabolism using microsensors and biosensors

Neurochemical pathways involved in brain physiology or disease pathogenesis are mostly unknown either in physiological conditions or in neurodegenerative diseases. Nowadays the most frequent usage for biotelemetry is in medicine, in cardiac care units or step-down units in hospitals, even if virtually any physiological signal could be transmitted (FCC, 2000; Leuher, 1983; Zhou et al., 2002). In this chapter we present a wireless device connected with microsensors and biosensors capable to detect real-time variations in concentrations of important compounds present in central nervous system (CNS) and implicated in brain energetic metabolism (Bazzu et al., 2009; Calia et al., 2009)

Region-Specific Dissociation between Cortical Noradrenaline Levels and the Sleep/ Wake Cycle

The activity of the noradrenergic system of the locus coeruleus (LC) is high in wake and low in sleep. LC promotes arousal and EEG activation, as well as attention, working memory, and cognitive flexibility. These functions rely on prefrontal cortex and are impaired by sleep deprivation, but the extent to which LC activity changes during wake remains unclear. Moreover, it is unknown whether noradrenergic neurons can sustain elevated firing during extended wake. Recent studies show that relative to LC neurons targeting primary motor cortex (M1), those projecting to medial prefrontal cortex (mPFC) have higher spontaneous firing rates and are more excitable. These results suggest that noradrenaline (NA) levels should be higher in mPFC than M1, and that during prolonged wake LC cells targeting mPFC may fatigue more

Chemically modified β-cyclodextrins useful in developing biosensors of agricultural and food relevance

β-cyclodextrin (β-CD), a natural, non-toxic cycloeptaamilose macrocycle, is a useful biomatrix for immobilizing enzymes on a biosensor surface because of the affinity of its cavity for hydrophobic guest molecules (e.g., aminoacids). In this work β-CD has been successfully modified with different poly-carboxylic acids (PCAs) including 1,2,3,4-butanetetracarboxylic acid. Time activation, pH, pressure and stoichiometry were optimized in order to achieve selected substitutions on the macrocycle hydroxy groups. The modified β-CDs, prepared under mild conditions, are completely water-soluble and could be grafted on a biosensor surface

Direct monitoring of ethanol in the brain

Introduction In the past few decades, ethanol has assumed the role of the most widespread psychotropic agent in Western society because of its availability to the youth and adults and also because it is generally considered legal in many societies. It is known that the alcohol can have significant relapses on the central nervous system; hence, there is a need for monitoring the toxicokinetics and the effects of ethanol on the brain with the most appropriate techniques. Among the techniques that aim to measure ethanol concentration in the brain, microdialysis has been the most widely used, but because of its invasiveness, associated with low temporal resolution, and the necessity of using connecting tubes to carry out the experiments, it is not particularly suitable for clinical trials. Recently, electrochemical biosensors, also minimally invasive, have been developed, which offer the possibility of monitoring the real-time variations of ethanol concentrations in the brain of animal models due to the very small dimensions of the transducer electrode. Recently, non-invasive methods have been used for the direct monitoring of alcohol in the brain, which use spectroscopic techniques such as magnetic resonance spectroscopy and magnetic resonance imaging or positron emission tomography, which are principally used to monitor ethanol metabolites. The aim of this review is to discuss all the techniques used to monitor brain ethanol and highlight their strengths and weaknesses. Conclusion Microdialysis and biosensors are primarily used in preclinical studies; both are very reliable techniques, but for invasiveness, they can only be used in animal models. Alternatively, spectroscopic techniques are suitable for both preclinical and clinical studies, and are not exclusive for animal models.</br

Temporal changes of conjugated linoleic acid in milk from Sarda ewes with different milk fat secretion ability

Individual milk samples were weekly collected from 48 ewes during eight weeks. Ewes were at the second month of lactation and they were fed the same dietary regimen. The animals were grouped according to the amount of daily milk fat yield: A) 38-57g/d, B) 58-63g/d, C) 64-73g/d, D) 75-110g/d. Milk from group D showed a higher content of FA from C4 to C10 and a lower content of monounsaturated FA (MUFA) and conjugated linoleic acids (CLA) than Group A (+12%, -11%, and -18%, for C4 to C10, MUFA and CLA, respectively), while Group B and C showed intermediate values. CLA content increased with days of lactation in a similar way for all groups. The mean correlation among all records within each individual lactation was 0.45 for CLA content. Six milk FA pair ratios representing a proxy for SCD activity were also evaluated: group A showed higher values of FA ratios than Group D (+26% on average for all FA pairs). In conclusion, increasing ability of daily milk fat yield was associated with lower milk content of MUFA and CLA and higher content of FA from C4 to C10

Synthesis and study of polyhydroxylated phenol derivatives with potential cosmetic and phytoiatric applications

Tyrosinase (polyphenol oxidase, E.C. 1.14.18.1) and laccase (phenol oxidase, E.C. 1.10.3.2) are multifunctional copper-containing enzymes, that are keys in melanin biosynthesis, melanisation in animals and browning in plants. Our study is aimed to prepare new monomer and dimer phenol derivatives as potential inhibitors of melanin production starting from natural hydroxylated aromatic units

An Ascorbate Bluetooth© Analyzer for Quality Control of Fresh-Cut Parsley Supply Chain

This work provides companies in the fresh-cut produce sector with an Ascorbate Bluetooth© Analyzer (ABA), a screen-printed sensor-based device for ascorbic acid (AA) detection, for quality control all along the supply chain. The amperometric detection of AA on fresh and fresh-cut parsley, under correct and incorrect storage temperature, allowed us to investigate the kinetics of AA decay in response to oxidative stress. The role of ascorbate oxidase (AOx) and ascorbate peroxidase (APx) was studied. ABA was used in situ by unskilled personnel. Treatments influenced AA decay kinetics, which were linear in fresh parsley, and non-linear in fresh-cut. Two hours at 28◦C immediately after chopping, the resilience of the fresh-cut parsley was reduced, even though the cold chain was restored. Two hours at −2◦C caused a rapid loss of AA until its complete decay after 72 h. Significant differences between treatments were observed in both the expression and activity of AOx and APx. ABA registered sudden changes of parsley AA following unpredicted variations of temperature during processing or transport. It was useful to remedy the effects of unexpected flaws in the cold chain, which can be proposed for quality preservation of different fresh-cut produce

Selective and sensitive poly-<i>ortho</i>-phenylenediamine-shielded microsensore and biosensors for in vivo neurochemical monitoring

Different methodologies are being developed, such as imaging, spectroscopy and electrochemistry, to study neurochemical dynamics in cell cultures or in intact brain [1-2]. One of these techniques involves the in-situ detection of biologically active molecules, including nitric oxide (NO) [3], glucose [4], glutamate (GLUT) [5-6] and lactate [1,7], in brain extracellular fluid (ECF), using implanted microsensors and biosensors. NO is a water-soluble free radical that readily diffuses through membranes and its actions in the CNS are largely studied

Neuroprotective effect of (R)-(-)-linalool on oxidative stress in PC12 cells

Background: Oxidative stress plays an important role in neurodegeneration, pain and inflammation. (R)-(-)- linalool (LIN) is endowed with neuroprotective, anti-nociceptive and anti-inflammatory properties. Purpose: The present study aims at investigating the hypothesis that LIN’s neuroprotective, antinociceptive and anti-inflammatory properties descend from its ability to act as antioxidant. The study challenges this hypothesis by verifying whether LIN may counteract hydrogen peroxide (H 2 O 2 )-induced oxidative stress in PC12 cells. Methods: In H 2 O 2 -exposed PC12 cells, LIN was tested on a) cell viability, measured by 3-(4,5-dimethylthiazol-2- yl)-2,5-diphenyltetrazolium bromide (MTT), b) damage of plasma membrane, measured by lactate dehydrogenase (LDH) release, c) intracellular levels of reactive-oxygen-species (ROS), d) apoptosis and e) cell cycle distribution. Results: Under H 2 O 2 -induced cell viability reduction, LIN protects PC12 cells. Likewise, LIN protects cells from oxidative damage by preventing the H 2 O 2 -dependent increase of LDH release, counteracts intracellular ROS overproduction and reduces H 2 O 2 -induced apoptosis. Finally, the results of the cell cycle analysis from cells exposed to H 2 O 2 indicate that LIN incubation reduces the number of cells induced into quiescence by H 2 O 2 in the G2/M phase. Conclusions: These findings indicate that LIN protects PC12 cells from H 2 O 2 -induced oxidative stress. This mech- anism could justify the neuroprotective, anti-nociceptive and anti-inflammatory effects of this compound and suggest LIN as a potential therapeutic agent for the management oxidative stress-mediated pain

Functionalization of Screen-Printed Sensors with a High Reactivity Carbonaceous Material for Ascorbic Acid Detection in Fresh-Cut Fruit with Low Vitamin C Content

In this study, carbon screen-printed sensors (C-SPEs) were functionalized with a high reactivity carbonaceous material (HRCM) to measure the ascorbic acid (AA) concentration in fresh-cut fruit (i.e., watermelon and apple) with a low content of vitamin C. HRCM and the functionalized working electrodes (WEs) were characterized by SEM and TEM. The increases in the electroactive area and in the diffusion of AA molecules towards the WE surface were evaluated by cyclic voltammetry (CV) and chronoamperometry. The performance of HRCM-SPEs were evaluated by CV and constant potential amperometry compared with the non-functionalized C-SPEs and MW-SPEs nanostructured with multi-walled carbon nanotubes. The results indicated that SPEs functionalized with 5 mg/mL of HRCM and 10 mg/mL of MWCNTs had the best performances. HRCM and MWCNTs increased the electroactive area by 1.2 and 1.4 times, respectively, whereas, after functionalization, the AA diffusion rate towards the electrode surface increased by an order of 10. The calibration slopes of HRCM and MWCNTs improved from 1.9 to 3.7 times, thus reducing the LOD of C-SPE from 0.55 to 0.15 and 0.28 μM, respectively. Finally, the functionalization of the SPEs proved to be indispensable for determining the AA concentration in the watermelon and apple samples