8 research outputs found
Fluorescence Biosensing in Nanopores
Hydrated nanopores offer a unique environment for studying biological molecules under controlled conditions and fabricating sensors using fluorescence. Silica nanopores for example are non-toxic, biologically and optically compatible with protein, and can be easily synthesized to entrap protein and exclude potentially interfering macromolecules, while transmitting analytes of interest. A well known problem when polymerizing orthosilicates to fabricate silica sol-gel nanopores is the release of alcohol, which denatures proteins. We will describe how using the fluorescence of PRODAN (6-propionyl-2-(N,N-dimethylamino)naphthalene) to monitor methanol generated during polymerization has helped define a protocol with enhanced biocompatibility. The improved biocompatibility of sol-gel nanopores synthesized using tetramethyl orthosilicate (TMOS) has been demonstrated by preserving the unstable native trimer form of allophycocyanin (APC) for up to 500 Hrs without the need to covalently binding the subunits together. This has enabled the observation of native APC trimer by means of its fluorescence in a pore down to the single molecule level. In this paper we demonstrate how PRODAN and another polarity sensitive dye, 9-diethylamino-5H-benzo[alpha]phenoxazine-5-one, Nile red (NR) report on pore polarity and successfully extend protein encapsulation to nanochannels of alumina (Al2O3). Improved biocompatibility of nanopores has potential impact in nanomedicine where the ability to study single biomolecules is a primary goal as it underpins our understanding of disease pathology and therapeutics at the most fundamental level. In sensing also the advantages of nanopore isolation of metabolite-specific protein for detecting non-fluorescent metabolites has been demonstrated. Similar approaches can in principle be developed for both single-molecules and lab-on-a-chip sensors
Extremely rapid isotropic irradiation of nanoparticles with ions generated in situ by a nuclear reaction
Mass production of nanoparticles containing well-controlled structural defects is a challenge. Here the authors demonstrate the feasibility of homogeneous ion irradiation generated in a nuclear reactor, for the preparation of fluorescent nanodiamonds and silicon carbide nanoparticles
Devices based on InGaN/GaN multiple quantum well for scintillator and detector applications
International audienc
Tailoring and Optimization of LuAG:Ce Epitaxial Film Scintillation Properties by Mg Co-Doping
Luminescence and scintillation properties of Lu3Al5O12 nanoceramics sintered by SPS method
Improved biocompatibility of protein encapsulation in sol-gel materials
By using the fluorescent dye 6-propionyl-2-(N,N-dimethylamino) naphthalene (PRODAN) to monitor methanol generated during tetramethyl orthosilicate polymerization we have optimised the encapsulation of protein in silica sol-gel monoliths with respect to completion of hydrolysis and distillation in order to remove methanol such that protein can be added without denaturation. A minimum of 24 h at +4 °C was found to be required before hydrolysis is complete and 3-5 min of vacuum distillation at 50 °C and 300 mbar needed to remove methanol before the gel is formed. The biocompatibility of a tetramethyl orthosilicate sol-gel monolith was demonstrated by preserving the trimer protein allophycocyanin (APC) in its native form for up to 500 h. This obviates the previously essential requirement of covalently binding the trimer together in order to prevent dissociation into monomers and has enabled observation of native APC trimer in a sol-gel pore for the first time down to the single molecule level using combined fluorescence spectroscopy and confocal microscopy. The higher stability afforded by the protocol we describe could impact on the application of sol-gel materials to single-molecule studies of wider bearing such as protein folding and aggregation