Search results for "Biosensing techniques"
showing 10 items of 96 documents
Multicomponent polymeric micelles based on polyaspartamide as tunable fluorescent pH-window biosensors
2010
Abstract PHEA-PEG 5000 -C 16 is a polyaspartamide polymer with appended hydrophilic PEG 5000 functions and hydrophobic n-C 16 units forming biocompatible micelles with a CAC as low as 1.8 × 10 −7 M. The protonation and acidity constants of the polymer's amino and carboxylic groups have been determined by potentiometric titrations at five different concentrations higher than CAC, finding concentration-independent values. Viscosity and polarity of the micellar core have been investigated by means of fluorescent probes, finding local values comparable to those of pure toluene and to the core of sodium dodecyl sulphate micelles, independently on the protonation degree of the polymer. The fluor…
DNA Origami-Mediated Substrate Nanopatterning of Inorganic Structures for Sensing Applications
2019
Structural DNA nanotechnology provides a viable route for building from the bottom-up using DNA as construction material. The most common DNA nanofabrication technique is called DNA origami, and it allows high-throughput synthesis of accurate and highly versatile structures with nanometer-level precision. Here, it is shown how the spatial information of DNA origami can be transferred to metallic nanostructures by combining the bottom-up DNA origami with the conventionally used top-down lithography approaches. This allows fabrication of billions of tiny nanostructures in one step onto selected substrates. The method is demonstrated using bowtie DNA origami to create metallic bowtie-shaped an…
Sea urchin coelomocytes as a novel cellular biosensor of environmental stress: a field study in the Tremiti Island Marine Protected Area, Southern Ad…
2007
The aim of the present study was to investigate on the suitability of the sea urchin as a sentinel organism for the assessment of the macro-zoobenthos health state in bio-monitoring programmes. A field study was carried out during two oceanographic campaigns using immuno-competent cells, the coelomocytes, from sea urchins living in a marine protected area. In particular, coelomocytes subpopulations ratio and heat shock protein 70 (HSC70) levels were measured in specimens of Paracentrotus lividus (Lamark, 1816) collected in two sampling sites, namely Pianosa and Caprara Islands, both belonging to the Tremiti Island Marine Protected Area (MPA) in the Southern Adriatic Sea, Italy. By density g…
Denaturing for Nanoarchitectonics: Local and Periodic UV-Laser Photodeactivation of Protein Biolayers to Create Functional Patterns for Biosensing
2022
[EN] The nanostructuration of biolayers has become a paradigm for exploiting nanoscopic light-matter phenomena for biosensing, among other biomedical purposes. In this work, we present a photopatterning method to create periodic structures of biomacromolecules based on a local and periodic mild denaturation of protein biolayers mediated by UV-laser irradiation. These nanostructures are constituted by a periodic modulation of the protein activity, so they are free of topographic and compositional changes along the pattern. Herein, we introduce the approach, explore the patterning parameters, characterize the resulting structures, and assess their overall homogeneity. This UV-based patterning…
Haptens, bioconjugates, and antibodies for penthiopyrad immunosensing
2014
4 pages, 1 table, 2 figures.
Revisited BIA-MS combination: Entire "on-a-chip" processing leading to the proteins identification at low femtomole to sub-femtomole levels
2008
International audience; We present the results of a study in which biomolecular interaction analysis (BIA, Biacore 2000) was combined with mass spectrometry (MS) using entire "on-a-chip" procedure. Most BIA-MS studies included an elution step of the analyte prior MS analysis. Here, we report a low-cost approach combining Biacore analysis with homemade chips and MS in situ identification onto the chips without elution step. First experiments have been made with rat serum albumin to determine the sensitivity and validation of the concept has been obtained with an antibody/antigen couple. Our "on-a-chip" procedure allowed complete analysis by MS-MS of the biochip leading to protein identificat…
Bacterial sensors based on biosilica immobilization for label-free OWLS detection
2013
In the last years, a new group of enzymes, the so-called silicateins, have been identified and characterized, which form the axial filaments of the spicules of the siliceous sponges, consisting of not only amorphous silica among others. These enzymes are able to catalyze the polycondensation and deposition of silica at mild conditions. Silicateins can be expressed in Escherichia coli. The recombinant proteins are expressed on the surface of the cell wall and are able to catalyze the formation of a polysilicate net around the bacterial cells providing the possibility for further attachment to the surface of SiO2 containing sensor chips. With this mild immobilization process it is now possibl…
Reversible Colorimetric Probes for Mercury Sensing
2005
The selectivity and sensitivity of two colorimetric sensors based on the ruthenium complexes N719 [bis(2,2'-bipyridyl-4,4'-dicarboxylate)ruthenium(II) bis(tetrabutylammonium) bis(thiocyanate)] and N749 [(2,2':6',2' '-terpyridine-4,4',4' '-tricarboxylate)ruthenium(II) tris(tetrabutylammonium) tris(isothiocyanate)] are described. It was found that mercury ions coordinate reversibly to the sulfur atom of the dyes' NCS groups. This interaction induces a color change in the dyes at submicromolar concentrations of mercury. Furthermore, the color change of these dyes is selective for mercury(II) when compared with other ions such as lead(II), cadmium(II), zinc(II), or iron(II). The detection limit…
BIO Bragg gratings on microfibers for label-free biosensing
2021
[EN] Discovering nanoscale phenomena to sense biorecognition events introduces new perspectives to exploit nano science and nanotechnology for bioanalytical purposes. Here we present Bio Bragg Gratings (BBGs), a novel biosensing approach that consists of diffractive structures of protein bioreceptors patterned on the surface of optical waveguides, and tailored to transduce the magnitude of biorecognition assays into the intensity of single peaks in the reflection spectrum. This work addresses the design, fabrication, and optimization of this system by both theoretical and experimental studies to explore the fundamental physicochemical parameters involved. Functional biomolecular gratings ar…
Quantification of the Raf-C1 Interaction With Solid-Supported Bilayers
2002
By use of the quartz crystal microbalance technique, the interaction of the Raf-Ras binding domain (RafRBD) and the cysteine-rich domain Raf-C1 with lipids was quantified by using solid-supported bilayers immobilized on gold electrodes deposited on 5 MHz quartz plates. Solid-supported lipid bilayers were composed of an initial octanethiol monolayer chemisorbed on gold and a physisorbed phospholipid monolayer varying in its lipid composition as the outermost layer. The integrity of bilayer preparation was monitored by impedance spectroscopy. For binding experiments, a protein construct comprising the RafRBD and Raf-C1 linked to the maltose binding protein and a His tag, termed MBP-Raf-C1, wa…