Synthesis of photoactivable Pt(IV) prodrug loaded on NaYF4 based upconversion nanoparticles functionalized with 2-deoxy-D-glucose and its evaluation for targeted cancer therapy

21-30Nano-formulation based on Tm, Yb doped NaYF4 upconversion nanoparticles (UCNPs) functionalized with 2-deoxy-D-glucose have been synthesized to load the photoactivable Pt(IV) prodrug, cis-[PtI2(NH3)2(OCOCH2CH2COOH)2]. The Pt(IV) prodrug has been synthesized by oxidation of cis-[PtI2(NH3)2] to [PtI2(OH)2(NH3)2] and its further treatment with succinic anhydride. It is loaded through ester bond formation between the carboxyl groups of Pt(IV) prodrug with hydroxyl groups of 2-deoxy-D-glucose (2-DG) coated on UCNPs. The cytotoxicity of formulation after exposing to 385 nm UV light and in absence of light is evaluated against MCF-7 cell lines by MTT assay. The results have revealed enhanced cytotoxicity of UV exposed nano-formulation. Additionally, the clonogenic assay has exhibited the decrease in plating efficiency as inferred from decreased surviving fraction around 20% only for UV activated formulation as compared to formulation in dark, as well as merely Pt(IV) prodrug. These results are indicative that more internalization of the formulation inside the cancer cells was achieved due to the presence of 2-DG rendering more efficiency to kill cancer cells

One pot synthesis of luminescent Mn doped ZnSe nanoparticles and its silica based water dispersible formulation for targeted delivery of doxorubicin

The manganese doped zinc selenide nanoparticles (ZnSe:Mn NPs) were synthesized by thermolysis method using oleic acid and oleylamine as a capping agent, 1-octadecene as solvent. Coating of mesoporous silica was done on ZnSe:Mn (ZnSe:Mn@mSilica) which was further functionalized with amine functional groups by treating with (3-aminopropyl)trimethoxysilane. Further pegylation was done to achieve water dispersibility by conjugating carboxyl groups of poly(ethylene glycol) diacid with the amine groups. These pegylated NPs were subsequently treated with ethylenediamine followed by acrylic acid. Conjugation of tris-(hydroxymethyl-aminomethan) was performed by Michael-type addition reaction to afford ZnSe:Mn@mSilica-PEG-Tris-OH. These TRIS functionalized NPs exhibited broad emission ranging from 590-620 nm that is an indicative for their suitability in diagnosis and monitoring progress of cancer treatment. To explore the usefulness of increased surface area because of mesoporosity, doxorubicin was loaded on ZnSe:Mn@mSilica-PEG-Tris-OH NPs through silyl ether linkage and evaluated for cytotoxicity against WEHI-164 mouse fibrosarcoma and RAJI human hematopoietic origin cancer cell lines. A decrease in 12 % of cell viability of WEHI-164 cells while 30% decrease in RAJI cell lines (IC50 ≈ 45 nM) were observed.  This shows that our formulation has more cytotoxic in RAJI cancer cell lines than that of WEHI-164 cancer cells. These results revealed that the formulation has potential for the application in drug delivery and diagnosis in chemotherapeutics

One pot synthesis of luminescent Mn doped ZnSe nanoparticles and their silica based water dispersible formulation for targeted delivery of doxorubicin

348-355The manganese doped zinc selenide nanoparticles (ZnSe:Mn NPs) have been synthesized by thermolysis method using oleic acid and oleylamine as capping agents, and 1-octadecene as solvent. Coating of mesoporous silica is done on ZnSe:Mn (ZnSe:Mn@mSilica) which is further functionalized with amine functional groups by treating with (3-aminopropyl)trimethoxysilane. Further pegylation is done to achieve water dispersibility by conjugating carboxyl groups of poly(ethylene glycol) diacid with the amine groups. These pegylated NPs are subsequently treated with ethylenediamine followed by acrylic acid. Conjugation of tris-(hydroxymethyl-aminomethane) is performed by Michael-type addition reaction to afford ZnSe:Mn@mSilica-PEG-Tris-OH. These tris functionalized NPs have exhibited broad emission ranging from 590-620 nm that is an indicative for their suitability in diagnosis and monitoring progress of cancer treatment. To explore the usefulness of increased surface area because of mesoporosity, doxorubicin is loaded on ZnSe:Mn@mSilica-PEG-Tris-OH NPs through silyl ether linkage and evaluated for cytotoxicity against WEHI-164 mouse fibrosarcoma and RAJI human hematopoietic origin cancer cell lines. A decrease in 12% of cell viability of WEHI-164 cells while 30% decrease in RAJI cell lines (IC50 ≈ 45 nM) are observed. This shows that our formulation has more cytotoxic in RAJI cancer cell lines than that of WEHI-164 cancer cells. These results reveal that the formulation has potential for the application in drug delivery and diagnosis in chemotherapeutics

TEA CO<SUB>2</SUB> laser-induced reaction of CH<SUB>3</SUB>NO<SUB>2</SUB> with CF<SUB>2</SUB>HCl: a mechanistic study

Dissociation of nitromethane has been observed when a mixture of CF2HCl and CH3NO2 is irradiated using pulsed TEA CO2 laser at 9R (24) line (1081 cm-1), which is strongly absorbed by CF2HCl but not by CH3NO2. Under low laser fluence conditions, only nitromethane dissociates, whereas at high fluence CF2HCl also undergoes dissociation, showing that dissociation occurs via the vibrational energy transfer processes from the TEA CO2 laser-excited CF2HCl to CH3NO2. Time-resolved infrared fluorescence from vibrationally excited CF2HCl and CH3NO2 molecules as well as UV absorption of CF2 radicals are carried out to elucidate the dynamics of excitation/dissociation and the chemical reactions of the dissociation products

Lyman-&#945; photodissociation of CH<SUB>3</SUB>CFCl<SUB>2</SUB> (HCFC-141b): quantum yield and translational energy of hydrogen atoms

The collision-free, room temperature gas-phase photodissociation dynamics of CH3CFCl2 (HCFC-141b) was studied using Lyman-&#945; laser radiation (121.6 nm) by the laser photolysis/laser-induced fluorescence 'pump/probe' technique. Lyman-&#945; radiation was used both to photodissociate the parent molecule and to detect the nascent H atom products via (2p 2P &#8594; 1s 2S) laser-induced fluorescence. Absolute H atom quantum yield, &#934;H = (0.39 &#177; 0.09) was determined by calibration method in which CH4 photolysis at 121.6 nm was used as a reference source of well-defined H atom concentrations. The line shapes of the measured H atom Doppler profiles indicate a Gaussian velocity distribution suggesting the presence of indirect H atom formation pathways in the Lyman-&#945; photodissociation of CH3CFCl2. The average kinetic energy of H atoms calculated from Doppler profiles was found to be E T(lab) = (50 &#177; 3) kJ/mol. The nearly statistical translational energy together with the observed Maxwell-Boltzmann velocity distribution indicates that for CH3CFCl2 the H atom forming dissociation process comes closer to the statistical limit

Multiphoton dissociation/ionisation of dimethyl sulphide (CH<SUB>3</SUB>SCH<SUB>3</SUB>) at 355 and 532 nm

Multiphoton dissociation/ionization has been studied for CH3SCH3 at 355 and 532 nm using a time-of-flight mass spectrometer. The major ion signals observed at 355 nm are C+, CH3 +, HCS+, CH2+, CH3S+ and CH3SCH3 +. Power dependence studies at 355 nm show a (2+1) REMPI process for the formation of parent ion. Peaks atm/e = 46, 47 and 61 show two-photon laser power dependence whereasm/e = 15 and 45 peaks show four-photon dependence. However, in 532 nm photo-ionisation, no parent ion signal is observed. A peak atm/e = 35 corresponding to SH3 + has been observed. SH3 + has been suggested to originate from CH3SCH2 + via a cyclic transition state. Photoionisation results of CH3SCH3 have been compared with those of CH3SSCH3, at these two wavelengths

Synthesis of photoactivable Pt(IV) prodrug loaded on NaYF4 based upconversion nanoparticles functionalized with 2-deoxy-D-glucose and its evaluation for targeted cancer therapy

Nano-formulation based on Tm, Yb doped NaYF4 upconversion nanoparticles (UCNPs) functionalized with 2-deoxy-D-glucose have been synthesized to load the photoactivable Pt(IV) prodrug, cis-[PtI2(NH3)2(OCOCH2CH2COOH)2]. The Pt(IV) prodrug has been synthesized by oxidation of cis-[PtI2(NH3)2] to [PtI2(OH)2(NH3)2] and its further treatment with succinic anhydride. It is loaded through ester bond formation between the carboxyl groups of Pt(IV) prodrug with hydroxyl groups of 2-deoxy-D-glucose (2-DG) coated on UCNPs. The cytotoxicity of formulation after exposing to 385 nm UV light and in absence of light is evaluated against MCF-7 cell lines by MTT assay. The results have revealed enhanced cytotoxicity of UV exposed nano-formulation. Additionally, the clonogenic assay has exhibited the decrease in plating efficiency as inferred from decreased surviving fraction around 20% only for UV activated formulation as compared to formulation in dark, as well as merely Pt(IV) prodrug. These results are indicative that more internalization of the formulation inside the cancer cells was achieved due to the presence of 2-DG rendering more efficiency to kill cancer cells

Interaction of nanosecond laser pulse with tetramethyl silane (Si(CH3)4) clusters: Generation of multiply charged silicon and carbon ions

Present work reports significantly high levels of ionization, eventually leading to Coulomb explosion of Tetramethyl silane (TMS) clusters, on interaction with laser pulses of intensity ∼109 W/cm2. Tetramethyl silane clusters, prepared by supersonic expansion were photoionized at 266, 355 or 532 nm and the resultant ions were detected using time-of-flight mass spectrometer. It is observed that wavelength of irradiation and the size of the cluster are crucial parameters which drastically affect the nature of charge species generated upon photoionization of cluster. The results show that clusters absorb significantly higher energy from the laser field at longer wavelengths (532 nm) and generate multiply charged silicon and carbon ions which have large kinetic energies. Further, laser-cluster interaction at different wavelengths has been quantified and charge densities at 266, 355 and 532 nm are found to be 4x 1010, 5x 1010 and 5x 1011 charges/cm3 respectively. These unusual results have been rationalized based on dominance of secondary ionization processes at 532 nm ultimately leading to Coulomb explosion of clusters. In another set of experiments, multiply charged ions of Ar (up to +5 state) and Kr (up to +6 state) were observed when TMS doped inert gas clusters were photoionized at 532 and 355 nm. The extent of energy absorption at these two wavelengths is clearly manifested from the charge state of the atomic ions generated upon Coulomb disintegration of the doped cluster. These experiments thus demonstrate a novel method for generation of multiply charged atomic ions of inert gases at laser intensity of ∼ 109 W/cm2. The average size of the cluster exhibiting Coulomb explosion phenomena under giga watt intensity conditions has been estimated to be ∼ 6 nm. Experimental results obtained in the present work agree qualitatively with the model proposed earlier [D. Niu, H. Li, F. Liang, L. Wen, X. Luo, B. Wang, and H. Qu, J. Chem. Phys. 122, 151103(2005)] and point towards interaction of quasi-free electrons, generated during primary multiphoton ionization step, with a given wavelength in the presence of Coulombic field

Laser spectroscopic excitation function and reaction threshold studies of the H + DCI → HCI + D gas phase isotopic exchange reaction

The dynamics of the gas-phase hydrogen atom exchange reaction H + DCl → HCl + D were studied using the pulsed laser photolysis/laser induced fluorescence "pump-and-probe" method. Laser photolysis of H2S at 222 nm was used to generate nonequilibrium distributions of translationally excited hydrogen atoms at high dilution in a flowing moderator gas (Ar)/reagent (DCl) mixture. H and D atoms were detected with sub-Doppler resolution via Lyman-α laser induced fluorescence spectroscopy, which allowed the measurement of the line shapes of the moderated H atom Doppler profiles as well as the concentration of the D atoms produced in the H + DCl → HCl + D reaction. From the measured H atom Doppler profiles, the time evolution of the initially generated nascent nonequilibrium H atom speed distribution toward its room-temperature thermal equilibrium form was determined. In this way, the excitation function and the reaction threshold (E0 = 0.65 ± 0.13 eV) for the H + DCl → HCl + D reaction could be determined from the measured nonequilibrium D atom formation rates and single collision absolute reaction cross-section values of 0.12 ± 0.04 Å2 and 0.45 ± 0.11 Å2 measured at reagent collision energies of 1.0 and 1.4 eV, respectively

Structural and luminescence studies on barium sodium borosilicate glasses containing uranium oxides

Barium sodium borosilicate glasses containing different amounts of uranium oxides were prepared by conventional melt quench method and investigated for their structural aspects by <SUP>29</SUP>Si and <SUP>11</SUP>B MAS NMR technique combined with steady-state luminescence and lifetime measurements. Based on MAS NMR studies, it is confirmed that uranium ions act as network modifier up to 15 wt% and beyond which a separate uranium containing phase is formed. From the luminescence studies, it is inferred that uranyl species is in a highly distorted environment. For more than 15 wt% uranium oxide incorporation, weaker U–O–U linkages are formed at the expense stronger U–O–Si/B linkages, as suggested by the excited state lifetime value of the uranyl species as well as red shift in emission peak maximum. For glass samples containing more than 25 wt% uranium oxides, crystalline barium uranium silicate gets phase separated from glass matrix as confirmed by XRD studies