Cisplatin-loaded polymeric nanoparticles: characterization and potential exploitation for the treatment of non-small cell lung carcinoma.

Cisplatin-loaded poly(l-glutamic acid)-g-methoxy poly(ethylene glycol 5K) nanoparticles (CDDP-NPs) were characterized and exploited for the treatment of non-small cell lung carcinoma (NSCLC). In vitro metabolism experiments showed that a glutamic acid 5-mPEG ester [CH3O(CH2CH2O)nGlu] was generated when the poly(l-glutamic acid)-g-methoxy poly(ethylene glycol 5K) (PLG-g-mPEG5K) was incubated with HeLa cells. This suggests that the poly(glutamic acid) backbone of the PLG-g-mPEG5K is biodegradable. Furthermore, the size of the CDDP-NPs in an aqueous solution was affected by varying the pH (5.0-8.0) and their degradation rate was dependent on temperature. The CDDP-NPs could also bind to the model nucleotide 2'-deoxyguanosine 5'-monophosphate, indicating a biological activity similar to cisplatin. The CDDP-NPs showed a significantly lower peak renal platinum concentration after a single systemic administration when compared to free cisplatin. In vivo experiments with a Lewis lung carcinoma (LLC) model showed that the CDDP-NPs suppressed the growth of tumors. In addition, LLC tumor-bearing mice treated with the CDDP-NPs (5mg/kg cisplatin eq.) showed much longer survival rates (median survival time: 51days) as compared with mice treated with free cisplatin (median survival time: 18days), due to the acceptable antitumor efficacy and low systemic toxicity of CDDP-NPs. These results suggest that the CDDP-NPs may be successfully applied to the treatment of NSCLC.

[Synthesis and fluorescence of KznF3 : Ce3+, Tb3+ nanoparticles].

Phosphors of KZnF3 : Ce3+, KZnF3 : Tb3+ and KZnF3 : Ce3+, Tb3+ nanoparticles were synthesized in a cetyltrimethylammonium bromide (CTAB)/2-octanol/water microemulsion system. X-ray diffraction (XRD) pattern was used to identify the formation of KZnF3 phase without detectable impurity. Environment scanning electron microscopy (ESEM) image showed that the average sizes of the KZnF3 : Ce3+ , Tb3+ nanocrystals were 30 nm in diameter. Photoluminescence characteristics of the rare earth ions doped nanoparticles were investigated and compared with that of the sample prepared by solid state reaction at a high temperature. The emission peak of the KZnF3 : Ce3+ nanoparticles showed an obvious red shift as compared to that of polycrystalline powder. In a co-doped system of KZnF3 nanoparticles, the emission band of Ce3+ even could hardly be observed and the luminescence intensity of Tb3+ was increased much compared with that Tb-doped singly. This showed that the emission of the Tb3+ was sensitized by Ce3+. The experimental results indicated that there was an effective energy transfer from Ce3+ to Tb3+ in KZnF3 nanoparticles.

Fabrication and spectroscopic broadening properties for 1.5 microm amplification of Er(3+)-doped BaF2 nanoparticles.

We show the potential application of Er(3+)-doped BaF2 nanoparticles prepared from microemulsion technology for 1.5 microm amplification in telecommunication. Nanoparticles with different sizes of about 8, 10, and 20.5 nm were prepared. The XRD patterns showed the excursion of diffraction peaks. When the particle size is smaller or the diffraction angle is larger, this kind of excursion will be more serious. The emission bands of Er3+ at 1.54 microm for the three particle sizes at were as follows: 8 nm particles--145 nm, 10 nm particles--124 nm, and 20.5 nm particles--82 nm (full width at half maximum, FWHM), or 173, 153, 97 nm (deltalambda(eff)), respectively. In all the three cases, the emission spectra were flat from 1.53 to 1.56 microm.

[Study on stimulated emission of Eu2+ in crystal KMgF3 : Eu2+].

The line emission peak of Eu2+ ion in crystal KMgF3 is at 360 nm. The probability of stimulated emission on 4f7 (6 P7/2 )-->4f7 (8 S7/2 ) transition was predicted with a four-level decay model of Eu2+ 6P7/2 excited states proposed by the authors. Optic gain and net gain coefficient (g=11. 4+/-3. 2)cm(-1) of 360 nm emission in crystal KMgF3 : Eu2+ were measured by ASE method, and the predication was proved by experiment. The net gain coefficient can be increased by annealing or doping crystal KMgF3 : Eu2+ with Gd3+ or Ce+.

Spontaneous ring-like self-assembly of BaF2 nanoparticles.

Self-assembly of BaF2 nanoparticles was described. BaF2 nanoparticles were prepared by microemulsion technology. The self-assembly of the particles is spontaneous without coating reagent on the surface or external force being applied during the procedure of sample preparation. XRD examination and ICP data showed the phase purity of the final product; FTIR spectroscopy confirmed that there was no organic species leaved in the product. By depositing one drop of colloid solution containing BaF2 particles on the TEM grid directly, we can get the ring-like self-assembly with larger particles dispersing peripherally to form a ring and smaller particles inside this ring forming circles.

[Concentration dependence of luminescence under different excitation wavelength in Y2O2S:Sm3+ phosphor].

The concentration dependence of luminescence under different excitations in Y2O2S:Sm3+ phosphor has been studied. The optimum activator concentration was found to be a function of the number of excited activator ions as well as the excitation wavelength. The concentration dependence curve of Y2O2S:Sm3+ phosphor under 413 nm excitation was different from the curve obtained with 263 nm excitation. For excitation radiation having longer wavelength (413 nm), the concentration quenching of Y2O2S:Sm3+ phosphor occurred at about 2%, which is ten times the result with shorter wavelength (263 nm) excitation (-0.2%). Fitting the concentration dependence curve and the result shows that the cross-relaxation caused by the dipole-quadrupole interaction of neighboring Sm3+ ions results in the concentration quenching.

Growth and vibrational spectra of doped KMgF3 single crystal.

The different ions doped KMgF(3) single crystals are prepared by the vertical Bridgman method. The near-infrared absorption spectra for different parts of all as-growth crystals indicate that there is the best transparency in middle part. The correlation between the vibronic frequencies of Eu(2+) and the site displacement of Cu(+) co-doped ions is firstly studied, which indicates that Cu(+) ions replace the site of the Mg(2+) ions. The co-doped Eu(2+) counteracts the charge misfit causing by the replacement of Mg(2+) with Cu(+). The overlapping of the emission spectra of the Eu(2+) and the excitation spectra of the Cu(+) results in the energy transfer from Eu(2+) to Cu(+).