Hydrothermal synthesis of monodisperse Ag2Se nanoparticles in the presence of PVP and KI and their application as oligonucleotide labels

Abstract

Monodispersed silver selenide (Ag 2 Se) nanoparticles have been prepared successfully by a hydrothermal reaction of AgNO 3 with Na 2 SeSO 3 in the presence of poly(vinyl pyrrolidone) (PVP) and KI at 180 C for 20 h. TEM revealed that the nanoparticles are much like husked rice with lengths of about 60-80 nm and widths of about 30-40 nm. KI was dispersed in a PVP solution first, then an appropriate amount of AgNO 3 solution was slowly added until the molar ratio of Ag + to I À reached 1 : 1. The formed complex ions of [Ag m I n ] (nÀm)À and AgI in the procedure are more stable owing to the protection effect of PVP, or these could be considered as complexes of PVP-[Ag m I n ] (nÀm)À and PVP-AgI. These complexes functioned as the precursors; the formation rate of Ag 2 Se crystal cores in the hydrothermal reaction could be well controlled. The final shape and size of the product were affected by the amount of PVP and the molar ratio of I À to Ag + , and higher PVP content was beneficial to the formation of the husked rice-like shape. The Ag 2 Se nanoparticles can be used for the detection of DNA hybridization. A specific DNA sequence related to the PEP promoter gene in transgenic plants was determined with a detection range from 1.0 Â 10 À12 to 1.0 Â 10 À8 mol L À1 and a detection limit of 2.3 Â 10 À13 mol L À1 (3s). The method had good selectivity and was successfully used to distinguish between a three-base mismatched ssDNA sequence, a non-complementary sequence and a complementary sequence. Experimental ReagentsSelenium powder, Na 2 SO 3 , AgNO 3 , KI, cetyltrimethyl ammonium bromide (CTAB), poly(vinyl pyrrolidone) (PVP, molecular

Preparation and characterization of monodispersed PbSe nanocubes

“…However, these reagents are very toxic and flammable. Recently, Chen et al [22] used Na 2 SeSO 3 solution as Se source to prepare monodispersed Ag 2 Se nanoparticles and Gao et al [23] also used Na 2 SeSO 3 solution to synthesize CdSe. It is therefore expected that Na 2 SeSO 3 can also be used to synthesize PbSe nanocrystals.…”

Low-Temperature Thermoelectric Properties of β-Ag2Se Synthesized by Hydrothermal Reaction

“…3 Recently, several groups have reported wet chemical synthesis (including hydrothermal preparation) of the compound. [9][10][11][12] However, characterizations of TE properties, especially at low temperature, are relatively rare for b-Ag 2 Se samples prepared by chemical routes.…”

Influence of Precursor Concentration and Temperature on the Formation of Nanosilver in Chemical Reduction Method

“…Bryaskova et al (2011) mentioned in their paper that the peak shifting was related to the formation of coordination bonds between silver atoms and oxygen or nitrogen atoms from PVP units. Basically, the characteristic peaks of PVP were detected in the S1T8 spectrum, indicating that the PVP molecules were adsorbed on the NSPs surface (Liu et al 2008). Table 2 summarizes the value of saturation magnetization (Ms), coercivity (Hc) and remanence (Mr) for all the sample.…”

“…A sharp peak of amide carbonyl group (-N-C=O) appeared at 1616 cm -1 was red-shifted from 1648 cm -1 peak in the PVP spectrum. According to Liu et al (2008) and Zhang et al (1996), the reduction of wavenumber for the C=O band might due to the weakening of bond via partial donation of oxygen to the silver. In the fingerprint region, a sharp and medium absorption band was detected at 1382 cm -1 which might be attributed to the nitrate ions as reported by Janardhanan et al (2009).…”