Search results for " Immobilization"
showing 10 items of 30 documents
Development of enzymatically-active bacterial cellulose membranes through stable immobilization of an engineered beta-galactosidase
2018
Enzymatically-active bacterial cellulose (BC) was prepared by non-covalent immobilization of a hybrid enzyme composed by a β-galactosidase from Thermotoga maritima (TmLac) and a carbohydrate binding module (CBM2) from Pyrococcus furiosus. TmLac-CBM2 protein was bound to BC, with higher affinity at pH 6.5 than at pH 8.5 and with high specificity compared to the non-engineered enzyme. Both hydrated (HBC) and freeze-dried (DBC) bacterial cellulose showed equivalent enzyme binding efficiencies. Initial reaction rate of HBC-bound enzyme was higher than DBC-bound and both of them were lower than the free enzyme. However, enzyme performance was similar in all three cases for the hydrolysis of 5% l…
Plasma modified PLA electrospun membranes for actinorhodin production intensification in Streptomyces coelicolor immobilized-cell cultivations
2017
Most of industrially relevant bioproducts are produced by submerged cultivations of actinomycetes. The immobilization of these Gram-positive filamentous bacteria on suitable porous supports may prevent mycelial cell-cell aggregation and pellet formation which usually negatively affect actinomycete submerged cultivations, thus, resulting in an improved biosynthetic capability. In this work, electrospun polylactic acid (PLA) membranes, subjected or not to O2-plasma treatment (PLA-plasma), were used as support for immobilized-cell submerged cultivations of Streptomyces coelicolor M145. This strain produces different bioactive compounds, including the blue-pigmented actinorhodin (ACT) and red-p…
Enhancement of antibiotic productions by plasma modified PLA electrospun membranes in Streptomyces coelicolor immobilized-cell cultivations
2017
This study, encouraging the use of PLA membranes for actinomycetes cultivations, could unveil functional insights associated with antibiotic production and S. coelicolor cellimmobilization
FUNCTIONAL EFFECT OF SHORT-TERM IMMOBILIZATION: KINEMATIC CHANGES AND RECOVERY ON REACHING-TO-GRASP
2012
Abstract Although previous investigations agree in showing significant cortical modifications related to short-term limb immobilization, little is known about the functional changes induced by non-use. To address this issue, we studied the kinematic effect of 10 h of hand immobilization. In order to prevent any movement, right handed healthy participants wore on their dominant hand a soft bandage. They were requested to perform the same reaching-to-grasping task immediately after immobilization, 1 day before (baseline 1) and in other two following days without non-use (baseline 2 and baseline 3). While no differences were found among baseline conditions, an increase of the total duration of…
Affinity Sensors for the Diagnosis of COVID-19
2021
The coronavirus disease 2019 (COVID-19) outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was proclaimed a global pandemic in March 2020. Reducing the dissemination rate, in particular by tracking the infected people and their contacts, is the main instrument against infection spreading. Therefore, the creation and implementation of fast, reliable and responsive methods suitable for the diagnosis of COVID-19 are required. These needs can be fulfilled using affinity sensors, which differ in applied detection methods and markers that are generating analytical signals. Recently, nucleic acid hybridization, antigen-antibody interaction, and change of reactive oxyge…
Tips on ligand immobilization and kinetic study using surface plasmon resonance.
2016
Surface plasmon resonance (SPR) technique offers a robust label-free approach applicable in various investigations including binding affinity, specificity and kinetics of biological macromolecules (e.g., peptides, proteins and nucleotidase) and small molecules. SPR provides extremely important data on the kinetics and affinity of substances examined, through which bio-specific interaction(s) can be established by the analysis of adsorption of analyte onto the immobilized ligand(s) on a sensor-based analytical system. Due to SPR wide applications in biomedical laboratories, the aim of this editorial is to highlight the importance of SPR in affinity kinetics and ligand immobilization.
Heterogeneous vs Homogeneous Palladium Catalysts for Cross-Coupling Reactions
2012
A large number of immobilized-Pd-catalysts for cross-coupling reactions have been introduced in the last decade. Are the observed catalyzed reactions truly heterogeneous or are they homogeneous due to leached palladium? This account critically addresses the leaching issue by selectively referring to some of the newly developed catalytic systems in an attempt to evaluate said systems based on uniform criteria. The report is concluded by identifying the relevant chemical and structural challenges in the field.
Multiplexed Sub-Cellular Scale Microarrays from direct DNA Nanolithography
2014
The multiplexed, high-throughput fabrication of microarrays is of vital importance for many applications in life sciences, including drug screening, medical diagnostics and cell biology. In single cell investigations, features smaller than 10 μm are needed for functional manipulation of sub-cellular structures. Several top-down methodologies like electron beam lithography and microcontact printing can be employed for indirect surface patterning at this scale, however those approaches often require clean rooms and multiplexing of several different biomolecules on the same surface is limited [1]. To overcome these obstacles, we combined Dip-pen nanolithography (DPN) and DNA-directed immobiliz…
Grafting of Hindered Phenol Groups onto Ethylene/α-Olefin Copolymer by Nitroxide Radical Coupling
2017
The covalent immobilization of hindered phenol groups, with potential antioxidant activity, onto an ethylene/α-olefin (EOC) copolymer was carried out by the nitroxide radical coupling (NRC) reaction performed in the melt with a peroxide and the 3,5-di-tert-butyl-4-hydroxybenzoyl-2,2,6,6-tetramethylpiperidine-1-oxyl radical (BHB-T). Functionalized EOC (EOC-g-(BHB-T)) was exposed to photo- and thermo-oxidation. By comparison with some model compounds bearing the (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) moiety or the hindered phenol unit, it was observed that the grafted BHB-T could effectively help the stabilization of the polymer matrix both under photo- and thermo-oxidation. In addit…
Configurable low-cost plotter device for fabrication of multi-color sub-cellular scale microarrays.
2014
We report on the construction and operation of a low-cost plotter for fabrication of microarrays for multiplexed single-cell analyses. The printing head consists of polymeric pyramidal pens mounted on a rotation stage installed on an aluminium frame. This construction enables printing of microarrays onto glass substrates mounted on a tilt stage, controlled by a Lab-View operated user interface. The plotter can be assembled by typical academic workshops from components of less than 15 000 Euro. The functionality of the instrument is demonstrated by printing DNA microarrays on the area of 0.5 squared centimeters using up to three different oligonucleotides. Typical feature sizes are 5 μm diam…