Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0267964 (PAA)
 2,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report on the use of block copolymer micelles of polystyrene-b-poly(acrylic acid) (PS-b-PAA) as matrixes for incorporating dibenzyl diselenide. We found that the water-insoluble diselenide, after being incorporated into the micelles, demonstrates glutathione peroxidase (GPx) activity in water. Surprisingly, the mimicking system can be adjusted to show higher GPx activity by increasing the ionic strength of the solution simply upon addition of NaCl. Moreover, dibenzyl diselenide incorporated into the micelles is quite stable and maintains its GPx activity even after exposure to the atmosphere.
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PMID:Block copolymer micelles as matrixes for incorporating diselenide compounds: a model system for a water-soluble glutathione peroxidase mimic fine-tuned by ionic strength. 1676 72

Silver nano-shells (SNSs) were synthesized via a two-step seeds-mediated method. Polymer cores were composed of ultrafine gold nanoparticles (NPs) modified chitosan-poly(acrylic acid) nanoparticles (CS-PAA NPs). Then, deposition of silver upon gold nucleus leads to the seed enlargement and finally forms silver shell on the surface of CS-PAA NPs to get SNSs. Transmission electron microscope (TEM) showed SNSs had a discrete silver shell plus some pores and gaps, which could acted as "hot spots" and provided the great potential of these SNSs to be used as SERS substrates with wavelength ranging from visible to infrared region (700-1000 nm) by tuning shell coverage of silver. SERS experiments with dibenzyl disulphide (DBDS) as the indicator showed that the resulting SNSs allowed the production of highly consistent enhancement of the Raman signals down to nM concentrations of DBDS. Considering the excellent biocompatibility of polymer core and their small size, these SNSs are highly desirable candidates as the enhancers for high performance SERS analysis and as SERS optical labels in biomedical imaging.
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PMID:Facile synthesis of polymer core@silver shell hybrid nanoparticles with super surface enhanced Raman scattering capability. 2326 32

Lanthanide-doped upconversion nanocrystals (UCNs) have attracted much attention in recent years based on their promising and controllable optical properties, which allow for the absorption of near-infrared (NIR) light and can subsequently convert it into multiplexed emissions that span over a broad range of regions from the UV to the visible to the NIR. This article presents detailed experimental procedures for high-temperature co-precipitation synthesis of core-shell UCNs that incorporate different lanthanide ions into nanocrystals for efficiently converting deep-tissue penetrable NIR excitation (808 nm) into a strong blue emission at 480 nm. By controlling the surface modification with biocompatible polymer (polyacrylic acid, PAA), the as-prepared UCNs acquires great solubility in buffer solutions. The hydrophilic nanocrystals are further functionalized with specific ligands (dibenzyl cyclooctyne, DBCO) for localization on the cell membrane. Upon NIR light (808 nm) irradiation, the upconverted blue emission can effectively activate the light-gated channel protein on the cell membrane and specifically regulate the cation (e.g., Ca2+) influx in the cytoplasm. This protocol provides a feasible methodology for the synthesis of core-shell lanthanide-doped UCNs and subsequent biocompatible surface modification for further cellular applications.
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PMID:Synthesis of Core-shell Lanthanide-doped Upconversion Nanocrystals for Cellular Applications. 2915 87