Nanoparticles uncapped

The biological impact of starch capped copper nanoparticles on mouse embryonic fibroblast (3T3L1) cells in vitro) was also evaluated by various parameters. More than 85 % of the 3T3Llcells were found to be viable, even after 20 hours time exposure which implies minimum impact on cell viability and morphology. The study demonstrates dose dependent cytotoxic potential of SCuNPs, that is non cytotoxic in the nanogram dose and moderately cytotoxic in the microgram doses (Fig. 10). Comparison of SCuNPs with Cu ions and uncapped copper nanoparticles (UCuNPs) revealed that, ions are more cytotoxic than SCuNPs. This observation supports the theory of slow release of ions from starch coated nanoparticles. 

Fig. 3 TGA curves of (a) 14 nm TOPO-capped MnO nanoparticles and (b) 3 nm uncapped NiO nanoparticles. The experiments were carried out in a nitrogen atmosphere at a heating rate of 10 °C min-1.

Figure 1. (a,b) TEM images of uncapped ZnO nanorods obtained after 3 and 12 h of reaction. The inset in (a) shows how a small ZnO nanoparticle attached to the side wall of an uncapped ZnO nanorod. The inset in (b) is a TEM image of uncapped ZnO nanorods obtained after 18 h of reaction. The arrow indicates the existence of small nanocrystal along with the nanorods. Several such nanocrystals can be seen in the image. (c,d) TEM images of PVP-capped ZnO nanorods obtained after 3 and 12 h of reaction. Note the absence of nanocrystals sticking to the nanorods. 

Fig. 10 Optical absorption and photoluminescence PL) spectra of the uncapped and PVP-capped ZnO nanoparticles. Reprinted with permission from [221]. Copyright 2000 American Physical Society...

Figure 35 Scheme for the entrapment of Rhodamine B, 133, in a pore of a MCM-41 nanoparticle, 134, through capping the pore by complexation of /3-CD on azobenzene derivatives attached to the nanoparticle surface, 135 (Steps 1 and 2). The Rhodamine B is subsequently released by uncapping the pore through photoisomerization of the azobenzene unit from the to Z form and decomplexation of /3-CD from 136 (Step 3). 

Hydrolyzable salts of metal ions are used for synthesis of corresponding oxides in colloidal form by their forced hydrolysis under hydrothermal conditions [322] or in high-boiling solvents (polyols) [323], Hydrolysis in nonaqueous solutions has been applied also to metal alkoxides [324] and diketonates [325], offering a convenient route to the uncapped nanoparticles. Synthesis of oxide nanocrystals has been directed to nonaqueous approaches [326-328] mostly inspired by the success of the synthesis of high quality semiconductor nanocrystals in nonaqueous media [329]. The quality of the nanocrystals yielded by these nonaqueous solution methods is generally better than that of the nanocrystals synthesized in aqueous solutions. 

Fig. 9.17 Emission spectrum 254 nm) and excitation spectrum (kem- 591 nm) of LaP04 O.5H2O nanocrystals doped with 10 % Eu uncapped nanowires (blue), TBP-capped nanoparticles (black), and nanowires (red) (Reprinted with the permission from Ref. [39]. Copyright 2009 American Chemical Society)...

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