Highly selective and sensitive nucleic acid detection based on polysaccharide-functionalized silver nanoparticles.

Polysaccharide-functionalized silver nanoparticles (Oc-AgNPs) with a mean diameter of 15 nm were utilized as a novel and effective fluorescence-sensing platform for nucleic acid detection. Tests on the oligonucleotide sequences associated with the human immunodeficiency virus as a model system showed that the Oc-AgNPs effectively absorbed and quenched dye-labeled single-stranded DNA through strong hydrogen bonding interactions and slight electrostatic attractive interactions. The proposed system efficiently differentiated between complementary and mismatched nucleic acid sequences with high selectivity and good reproducibility at room temperature.

Effect of extraction media on preliminary characterizations and antioxidant activities of Phellinus linteus polysaccharides.

Three partially purified polysaccharides were extracted from Phellinus linteus mycelia using hot water, 1% (NH4)2C2O4, and 1.25M NaOH/0.05% NaBH4, and the extracts were named PL-W, PL-A, and, PL-N respectively.

Structural characteristics and antioxidant activities of different families of 4-acetamido-TEMPO-oxidised curdlan.

Regioselective oxidation was applied to commercial curdlan for the preparation of its water-soluble derivatives with improved antioxidant activities, using a 4-acetamido-2,2, 6,6-tetramethylpiperidine-1-oxyl radical/NaClO/NaClO2 system at pH 4.8 and 40°C. The structural features, molecular properties, and chain conformations of the oxidised curdlans were determined using Fourier transform (FT) infrared and FT Raman spectroscopy, carbon nuclear magnetic resonance, X-ray diffraction, and size-exclusion chromatography with multi-angle laser-light scattering analyses.

Green synthesis of silver nanoparticles using 4-acetamido-TEMPO-oxidized curdlan.

A facile, simple, and eco-friendly method using 4-acetamido-2,2,6,6-tetramethypiperidine-1-oxyl radical-oxidized curdlan (Oc) as both reducing and stabilizing agents was developed for the fabrication of silver nanoparticles (AgNPs) from silver nitrate (AgNO₃). The structure, morphology, and particle size of the as-prepared AgNPs were investigated by ultraviolet-visible spectroscopy, transmission electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction, and dynamic laser light scattering. The well-dispersed AgNPs were sphere like with a mean diameter of 15 nm.