Bio)Sensor Approach in the Evaluation of Polyphenols in Vegetal Matrices

Polyphenols are compounds widely distributed in the plant kingdom and have attracted much attention, because of their health benefits and important properties such as radical scavenging, metal chelating agents, inhibitors of lipoprotein oxidation, anti-inflammatory and anti-allergic activities. Due to their important role in the diet and in therapy, it is important to estimate their content in the different matrices of interest. Besides classical analytical methods, new emerging technologies have also appeared in the last decade aiming for simple and eventually cheap detection of polyphenols. This review focused on the recent applications of biosensing-based technologies for polyphenol estimation in vegetal matrices, using different transduction principles. These analytical tools are generally fast, giving responses in the order of a few seconds/minutes, and also very sensitive and generally selective (mainly depending on the enzyme used). Direct measurements in most of the investigated matrices were possible, both in aqueous and organic phases

Self-powered microneedle-based biosensors for pain-free high-accuracy measurement of glycaemia in interstitial fluid

In this work a novel self-powered microneedle-based transdermal biosensor for pain-free high-accuracy real-time measurement of glycaemia in interstitial fluid (ISF) is reported. The proposed transdermal biosensor makes use of an array of silicon-dioxide hollow microneedles that are about one order of magnitude both smaller (borehole down to 4 µm) and more densely-packed (up to 1×106 needles/cm2) than state-of-the-art microneedles used for biosensing so far. This allows self-powered (i.e. pump-free) uptake of ISF to be carried out with high efficacy and reliability in a few seconds (uptake rate up to 1 µl/s) by exploiting capillarity in the microneedles. By coupling the microneedles operating under capillary-action with an enzymatic glucose biosensor integrated on the back-side of the needle-chip, glucose measurements are performed with high accuracy (±20% of the actual glucose level for 96% of measures) and reproducibility (coefficient of variation 8.56%) in real-time (30 s) over the range 0–630 mg/dl, thus significantly improving microneedle-based biosensor performance with respect to the state-of-the-art

Real-time kinetic binding studies at attomolar concentrations in solution phase using a single-stage opto-biosensing platform based upon infrared surface plasmons

Here we present a new generic opto-bio-sensing platform combining immobilised aptamers on an infrared plasmonic sensing device generated by nano-structured thin film that demonstrates amongst the highest index spectral sensitivities of any optical fibre sensor yielding on average 3.4 × 104 nm/RIU in the aqueous index regime (with a figure of merit of 330) This offers a single stage, solution phase, atto-molar detection capability, whilst delivering real-time data for kinetic studies in water-based chemistry. The sensing platform is based upon optical fibre and has the potential to be multiplexed and used in remote sensing applications. As an example of the highly versatile capabilities of aptamer based detection using our platform, purified thrombin is detected down to 50 attomolar concentration using a volume of 1mm3 of solution without the use of any form of enhancement technique. Moreover, the device can detect nanomolar levels of thrombin in a flow cell, in the presence of 4.5% w/v albumin solution. These results are important, covering all concentrations in the human thrombin generation curve, including the problematic initial phase. Finally, selectivity is confirmed using complementary and non-complementary DNA sequences that yield performances similar to those obtained with thrombin

Clinical features and therapeutic management of patients admitted to Italian acute hospital psychiatric units: the PERSEO (psychiatric emergency study and epidemiology) survey

<p>Abstract</p> <p>Background</p> <p>The PERSEO study (psychiatric emergency study and epidemiology) is a naturalistic, observational clinical survey in Italian acute hospital psychiatric units, called SPDCs (Servizio Psichiatrico Diagnosi e Cura; in English, the psychiatric service for diagnosis and management). The aims of this paper are: (i) to describe the epidemiological and clinical characteristics of patients, including sociodemographic features, risk factors, life habits and psychiatric diagnoses; and (ii) to assess the clinical management, subjective wellbeing and attitudes toward medications.</p> <p>Methods</p> <p>A total of 62 SPDCs distributed throughout Italy participated in the study and 2521 patients were enrolled over the 5-month study period.</p> <p>Results</p> <p>Almost half of patients (46%) showed an aggressive behaviour at admission to ward, but they engaged more commonly in verbal aggression (38%), than in aggression toward other people (20%). A total of 78% of patients had a psychiatric diagnosis at admission, most frequently schizophrenia (36%), followed by depression (16%) and personality disorders (14%), and no relevant changes in the diagnoses pattern were observed during hospital stay. Benzodiazepines were the most commonly prescribed drugs, regardless of diagnosis, at all time points. Overall, up to 83% of patients were treated with neuroleptic drugs and up to 27% received more than one neuroleptic either during hospital stay or at discharge. Atypical and conventional antipsychotics were equally prescribed for schizophrenia (59 vs 65% during stay and 59 vs 60% at discharge), while atypical drugs were preferred in schizoaffective psychoses (72 vs 49% during stay and 70 vs 46% at discharge) and depression (41 vs 32% during stay and 44 vs 25% at discharge). Atypical neuroleptics were slightly preferred to conventional ones at hospital discharge (52 vs 44%). Polypharmacy was in general widely used. Patient attitudes toward medications were on average positive and self-reported compliance increased during hospital stay.</p> <p>Conclusion</p> <p>Results confirm the widespread use of antipsychotics and the increasing trend in atypical drugs prescription, in both psychiatric in- and outpatients.</p

Protein-templated copper nanoclusters for fluorimetric determination of human serum albumin

Copper nanoclusters (CuNCs) are attractive for their unique optical properties, providing sensitive fluorescent detection of several kinds of targets even in complex matrices. Their ability in growing on suitable protein and nucleic acid templates make CuNCs efficient optical reporters to be exploited in bioanalysis. In this work, we report the specific and sensitive determination of human serum albumin (HSA) in human serum (HS) and urine via CuNCs fluorescence. HSA is the most abundant protein in plasma, and plays a key role in the early diagnosis of serious pathological conditions such as albuminuria and albuminemia. Recently, HSA has become clinically central also as a biomarker to assess severity, progression, and prognosis of various cancers. We report the controlled and reproducible growth of CuNCs directly on the target analyte, HSA, which results in a fine dose-dependent fluorescent emission at 405 nm. The protocol is optimized in water, and then applied to serum and urine specimens, without matrix pretreatment. The method linearly responds within the whole concentration of clinical interest, with a sensitivity of 1.8 ± 0.1 × 10-3 g L-1 and 0.62 ± 0.03 × 10-3 g L-1 in serum and urine, respectively, and excellent reproducibility (CVav% ca. 3% for both). The assay is designed to have a single protocol working for both matrices, with recovery of 95% (HS) and 96% (urine). The stability of the fluorescence after CuNCs formation was tested over 3 days, displaying good results (yet higher in urine than in serum)

A Piezoelectric Biosensor as a Direct Affinity Sensor

It is well - known that the resonant frequency of an oscillating piezoelectric crystal can be affected by a change in mass at the crystal surface. 1 This method can be used as sensor for protein adsorption studies and for direct immunosensing. Up to now these studies have been performed by measuring the frequency in dry state, i.e. with the "dip and dry" technique which is rather cumbersome and time consuming. Recently we obtained some results with piezoelectric crystals used directly in liquid solutions. We will discuss a real-time monitoring of (i) adsorption of the human immunoglobulin Ig G (h -Ig G); (ii) the affinity reaction between covalently immobilized antigen (the pesticide 2,4 -D) and specific monoclonal antibodies (Mab anti- 2,4-D) from two different clones (clone F6C 10 and clone E2G2); and, (iii) immunoreactions between immobilized antigen and antibodies performing a competitive assay. All experiments show how the reaction under study is linked to a mass increase which can be monitored continuously in real time. Direct antigen - antibody interaction can, thus, be studied without any kind of label. A microprocessor controlled piezoelectric detector as sensor was employed to monitor in real time protein adsorption and immunoreactions using piezoelectric quartz crystals (AT-cut) with basic resonant frequency of 10 MHz. The adsorbed protein was an immunoglobulin (h -Ig G); in the immunosensing a covalent immobilized molecule (the pesticide 2,4 -D) formed the receptor for the immobilized ligand sample (Mab anti- 2,4- D) in a competitive assay

Detection of pesticide in Drinking water using real-time Biospecific Interaction Analysis (BIA)

Analytical Letters issn 0003271