Label-free fiber optic optrode for the detection of class C beta-lactamases expressed by drug resistant bacteria

This paper reports the experimental assessment of an automated optical assay based on label free optical fiber optrodes for the fast detection of class C beta-lactamases (AmpC BLs), actually considered as one of the most important sources of resistance to beta-lactams antibiotics expressed by resistant bacteria. Reflection-type long period fiber gratings (RT-LPG) have been used as highly sensitive label free optrodes, while a higher affine boronic acid based ligand was here selected to enhance the overall assay performances compared to those obtained in our first demonstration. In order to prove the feasibility analysis towards a fully automated optical assay, an engineered system was developed to simultaneously manipulate and interrogate multiple fiber optic optrodes in the different phases of the assay. The automated system tested in AmpC solutions at increasing concentrations demonstrated a limit of detection (LOD) of 6 nM, three times better when compared with the results obtained in our previous work. Moreover, the real effectiveness of the proposed optical assay has been also confirmed in complex matrices as the case of lysates of Escherichia coli overexpressing AmpC. (C) 2017 Optical Society of Americ

Production of biodegradable superabsorbent aerogels using a supercritical CO2 assisted drying

Superabsorbent polymers (SAPs) are organic materials possessing high capacity to absorb and retain large volumes of water, saline and physiological solutions (at least 10–20 times their weight). The most commonly used SAPs are acrylated-based polymers that are not biodegradable or recyclable. To overcome these limits, carboxymethylcellulose (CMC) with hydroxyethylcellulose (HEC) hydrogels were synthetized in this work and dried using a supercritical assisted process at 200 bar and 45 °C. The solvent exchange procedure influenced the final aerogel morphology and, thus, the aerogel swelling ratio (SR). A solvent exchange starting from 50 % v/v ethanol, preserved the native gel nanofibrous morphology, producing a SR up to 20 times larger than the ones reported in the literature using the same process, corresponding to a water uptake larger than 500 times the weight of the dried aerogel

Reflection-type long period grating biosensor for the detection of drug resistant bacteria: The Opto-bacteria Project

We report on the development of a multilayer coated reflection-type long period fiber grating (LPG) biosensor, useful for the detection of antibiotic resistance bacteria. A standard LPG is first transformed in a more practical probe working in reflection mode, then it is coated by a primary layer of aPS and a secondary layer of PMMA in order to increase its surrounding refractive index sensitivity and at the same time provide the necessary conditions for a correct biofunctionalization. Standard linkage chemistry has been applied to anchor the bioreceptors on the probe surface. We show some preliminary results demonstrating the capability of our LPG biosensor to successfully monitor all the biological steps of the biomolecular experiments, including β-lactamase binding detection tests. © 2014 SPIE

Reflection-type long period grating biosensor for detection of drug resistant bacteria: The OptoBacteria project

In this paper, we report the experimental results on the fabrication and validation of a multilayer coated reflection-type long period fiber grating (LPG) biosensor, useful for the detection of antibiotic resistance bacteria. A standard LPG is first transformed in a practical probe working in reflection mode, then it is coated by two layers: atactic polystyrene (aPS) and (methyl methacrylate-co-methacrylic acid) (PMMA-co-MA). This multilayer strategy allow, at same time, to increase the surrounding refractive index sensitivity of the standard LPG and create the necessary conditions for a correct bio-functionalization. Standard linkage chemistry has been applied to anchor the bioreceptors on the probe surface. The experimental results demonstrate the capability of our LPG biosensor to successfully monitor all the biological steps of the biomolecular experiments, with β-lactamase AmpC binding detection tests obtained using two different ligands characterized by two different β-lactamase affinities

Long period fiber grating biosensor for the detection of drug resistant bacteria: The 'OPTObacteria' project

We report on the development of a multilayer coated reflection-type long period fiber grating (LPG) biosensor, useful for the detection of antibiotic resistance bacteria. A standard LPG is first transformed in a more practical probe working in reflection mode, then it is coated by a primary layer of aPS and a secondary layer of PMMA in order to increase its surrounding refractive index sensitivity and at the same time provide the necessary conditions for a correct bio-functionalization. Standard linkage chemistry has been applied to anchor the bioreceptors on the probe surface. We show some preliminary results demonstrating the capability of our LPG biosensor to successfully monitor all the biological steps of the biomolecular experiments, including \u3b2-lactamase binding detection tests. \ua9 2014 IEEE

Long period fiber grating working in reflection mode as valuable biosensing platform for the detection of drug resistant bacteria

We report here on a reflection-type long period fiber grating (RT-LPG) biosensor for the fast detection of class C (AmpC) \u3b2-lactamases (BLs), actually considered as one of the most important source of resistance to \u3b2-lactam antibiotics expressed by resistant bacteria. A standard LPG working in transmission configuration is first transformed in a more practical probe working in reflection mode and successively coated with a primary high refractive index (HRI) overlay of atactic polystyrene (aPS) in order to increase its surrounding refractive index sensitivity (SRI) in biological solutions. The aPS-coated RT-LPG is then coated by a secondary layer of poly(methylmethacrylate)-co-methacrylic acid (PMMA-co-MA) in order to provide the necessary surface functionalities to promote a stable covalent bioreceptors immobilization. The BLs detection has been performed by using the 3-aminophenylboronic acid (3-APBA) as biorecognition element, due to its excellent inhibition properties against class C BLs and specificity. Results here provided demonstrate that the proposed label free biosensor is capable of reliable detection of purified AmpC BLs in phosphate buffer solutions (PBS) with concentrations as low as one hundred nM, with a lowest limit of detection (LOD) of the order of a few tens of nM. The real effectiveness of the proposed biosensor has been also confirmed in lysate samples, which contain Escherichia coli bacteria overexpressing AmpC BLs

FOS-based thermo-hygrometers in the ATLAS Inner Detector

We present the main steps of FOS (based on LPG and FBG) installation in the CERN-ATLAS experiment for temperature and humidity measurements, from laboratory calibrations and data acquisition chain development, to their installation and operation

Fiber optic sensors in the ATLAS Inner Detector

A prototype system of Fiber Optic Sensors (FOS) for the accurate measurement of temperature and relative humidity, has been installed inside the Inner Detector volume of the ATLAS experiment at the LHC. The goal is to evaluate the behavior of the technology against radiation effects, and possibly to assess its suitability for future collider experiments, starting from HL-LHC. It follows the description of the work that has led to the choice of the sensors, their testing and calibration in the laboratory, their successive installation and operation in ATLAS, and the development of the data acquisition chain. The first results on performance are reported

Fiber optic sensors in the ATLAS Inner Detector

A prototype system of Fiber Optic Sensors (FOS) for the accurate measurement of temperature and relative humidity, has been installed inside the Inner Detector volume of the ATLAS experiment at the LHC. The goal is to evaluate the behavior of the technology against radiation effects, and possibly to assess its suitability for future collider experiments, starting from HL-LHC. It follows the description of the work that has led to the choice of the sensors, their testing and calibration in the laboratory, their successive installation and operation in ATLAS, and the development of the data acquisition chain. The first results on performance are reported