To improve the anti-tumor activity of hydrophobic drug curcumin, we prepared curcumin-loaded PLGA nanoparticles （PLGA-Cur NPs） through a modified spontaneous emulsification solvent diffusion （modified-SESD） method...To improve the anti-tumor activity of hydrophobic drug curcumin, we prepared curcumin-loaded PLGA nanoparticles （PLGA-Cur NPs） through a modified spontaneous emulsification solvent diffusion （modified-SESD） method. The influence of main preparation parameters was investigated, such as the volume ratio of binary organic solvents and the concentration of surfactant. Results indicated that the synthesized regular spherical PLGA NPs with the average diameter of 189.7 nm exhibited relatively higher yield （58.9%）, drug loading （11.0% （w/w）） and encapsulation efficiency （33.5%）, and also a controllable drug release profile. In order to evaluate the in vitro cytotoxicity of the prepared NPs, MTT assay was conducted, and results showed that the NPs could effectively inhibit HL60 and HepG2 cells with lower IC50 values compared with free curcumin. Furthermore, confocal microscopy together with flow cytometry analysis proved the enhanced apoptosis-inducing ability of PLGA-Cur NPs. Polymeric NP formulations are potential to be used for hydrophobic drug delivery systems in cancer therapy.展开更多
Development of electrochemical DNA hybridization biosensors based on carbon paste electrode （CPE） and gold nanoparticle modified carbon paste electrode （NGMCPE） as transducers and ethyl green （EG） as a new elect...Development of electrochemical DNA hybridization biosensors based on carbon paste electrode （CPE） and gold nanoparticle modified carbon paste electrode （NGMCPE） as transducers and ethyl green （EG） as a new electroac- tive label is described. Electrochemical impedance spectroscopy and cyclic voltammetry techniques were applied for the investigation and comparison of bare CPE and NGMCPE surfaces. Our voltammetric and spectroscopic studies showed gold nanoparticles are enable to facilitate electron transfer between the accumulated label on DNA probe modified electrode and electrode surface and enhance the electrical signals and lead to an improved detection limit. The immobilization of a 15-mer single strand oligonucleotide probe on the working electrodes and hybridiza- tion event between the probe and its complementary sequence as a target were investigated by differential pulse voltammetry （DPV） responses of the EG accumulated on the electrodes. The effects of some experimental variables on the performance of the biosensors were investigated and optimum conditions were suggested. The selectivity of the biosensors was studied using some non-complementary oligonucleotides. Finally the detection limits were calculated as 1.35×10^-10 mol/L and 5.16×10^-11 mol/L on the CPE and NEGCPE, respectively. In addition, the bio-sensors exhibited a good selectivity, reproducibility and stability for the determination of DNA sequences.展开更多
A magnetic bar carbon paste electrode （MBCPE） modified with Fe3O4 magnetic nanoparticles （Fe3O4NPs） and 2‐（3,4‐dihydroxyphenyl） benzothiazole （DPB） for the electrochemical determina‐tion of hydrazine was de...A magnetic bar carbon paste electrode （MBCPE） modified with Fe3O4 magnetic nanoparticles （Fe3O4NPs） and 2‐（3,4‐dihydroxyphenyl） benzothiazole （DPB） for the electrochemical determina‐tion of hydrazine was developed. The DPB was firstly self‐assembled on the Fe3O4NPs, and the re‐sulting Fe3O4NPs/DPB composite was then absorbed on the designed MBCPE. The MBCPE was used to attract the magnetic nanoparticles to the electrode surface. Owing to its high conductivity and large effective surface area, the novel electrode had a very large current response for the electrocat‐alytic oxidation of hydrazine. The modified electrode was characterized by voltammetry, scanning electron microscopy, electrochemical impedance spectroscopy, infrared spectroscopy, and UV‐visible spectroscopy. Voltammetric methods were used to study the electrochemical behaviour of hydrazine on MBCPE/Fe3O4NPs/DPB in phosphate buffer solution （pH = 7.0）. The MBCPE/Fe3O4NPs/DPB, acting as an electrochemical sensor, exhibited very high electrocatalytic activity for the oxidation of hydrazine. The presence of DPB was found to reduce the oxidation potential of hydrazine and increase the catalytic current. The dependence of the electrocatalytic current on the hydrazine concentration exhibited two linear ranges, 0.1–0.4 μmol/L and 0.7–12.0 μmol/L, with a detection limit of 18.0 nmol/L. Additionally, the simultaneous determination of hydrazine and phe‐nol was investigated using the MBCPE/Fe3O4NPs/DPB electrode. Voltammetric experiments showed a linear range of 100–470 μmol/L and a detection limit of 24.3 μmol/L for phenol, and the proposed electrode was applied to the determination of hydrazine and phenol in water samples.展开更多
An antireflection （AR） coating is fabricated by applying an optimal spin-coating method and a pH-modified SiO2 nanoparticle solution on a cover glass. Because the pH value of the solution will affect the aggregation...An antireflection （AR） coating is fabricated by applying an optimal spin-coating method and a pH-modified SiO2 nanoparticle solution on a cover glass. Because the pH value of the solution will affect the aggregation and dispersion of the SiO2 particles, the transmittance of the AR-treated cover glass will be enhanced under optimal fabricated conditions. The experimental results show that an AR coating fabricated by an SiO2 nano- particle solution of pH 11 enhances the transmittance approximately by 3% and 5% under normal and oblique incident conditions, respectively. Furthermore, the AR-treated cover glass exhibits hydrophobicity and shows a 65% enhancement at a contact angle to bare glass.展开更多
基金This work was supported by the National Natural Science Foundation of China （Grant Nos. 51272236 and 51002139）, the Science Foundation ofZhejiang Sci-Tech University （Grant Nos. 13042158- Y, 0716687-Y and 0816833-Y）, and the Zhejiang Provincial Top Key Discipline of Biology.
文摘To improve the anti-tumor activity of hydrophobic drug curcumin, we prepared curcumin-loaded PLGA nanoparticles （PLGA-Cur NPs） through a modified spontaneous emulsification solvent diffusion （modified-SESD） method. The influence of main preparation parameters was investigated, such as the volume ratio of binary organic solvents and the concentration of surfactant. Results indicated that the synthesized regular spherical PLGA NPs with the average diameter of 189.7 nm exhibited relatively higher yield （58.9%）, drug loading （11.0% （w/w）） and encapsulation efficiency （33.5%）, and also a controllable drug release profile. In order to evaluate the in vitro cytotoxicity of the prepared NPs, MTT assay was conducted, and results showed that the NPs could effectively inhibit HL60 and HepG2 cells with lower IC50 values compared with free curcumin. Furthermore, confocal microscopy together with flow cytometry analysis proved the enhanced apoptosis-inducing ability of PLGA-Cur NPs. Polymeric NP formulations are potential to be used for hydrophobic drug delivery systems in cancer therapy.
文摘Development of electrochemical DNA hybridization biosensors based on carbon paste electrode （CPE） and gold nanoparticle modified carbon paste electrode （NGMCPE） as transducers and ethyl green （EG） as a new electroac- tive label is described. Electrochemical impedance spectroscopy and cyclic voltammetry techniques were applied for the investigation and comparison of bare CPE and NGMCPE surfaces. Our voltammetric and spectroscopic studies showed gold nanoparticles are enable to facilitate electron transfer between the accumulated label on DNA probe modified electrode and electrode surface and enhance the electrical signals and lead to an improved detection limit. The immobilization of a 15-mer single strand oligonucleotide probe on the working electrodes and hybridiza- tion event between the probe and its complementary sequence as a target were investigated by differential pulse voltammetry （DPV） responses of the EG accumulated on the electrodes. The effects of some experimental variables on the performance of the biosensors were investigated and optimum conditions were suggested. The selectivity of the biosensors was studied using some non-complementary oligonucleotides. Finally the detection limits were calculated as 1.35×10^-10 mol/L and 5.16×10^-11 mol/L on the CPE and NEGCPE, respectively. In addition, the bio-sensors exhibited a good selectivity, reproducibility and stability for the determination of DNA sequences.
文摘A magnetic bar carbon paste electrode （MBCPE） modified with Fe3O4 magnetic nanoparticles （Fe3O4NPs） and 2‐（3,4‐dihydroxyphenyl） benzothiazole （DPB） for the electrochemical determina‐tion of hydrazine was developed. The DPB was firstly self‐assembled on the Fe3O4NPs, and the re‐sulting Fe3O4NPs/DPB composite was then absorbed on the designed MBCPE. The MBCPE was used to attract the magnetic nanoparticles to the electrode surface. Owing to its high conductivity and large effective surface area, the novel electrode had a very large current response for the electrocat‐alytic oxidation of hydrazine. The modified electrode was characterized by voltammetry, scanning electron microscopy, electrochemical impedance spectroscopy, infrared spectroscopy, and UV‐visible spectroscopy. Voltammetric methods were used to study the electrochemical behaviour of hydrazine on MBCPE/Fe3O4NPs/DPB in phosphate buffer solution （pH = 7.0）. The MBCPE/Fe3O4NPs/DPB, acting as an electrochemical sensor, exhibited very high electrocatalytic activity for the oxidation of hydrazine. The presence of DPB was found to reduce the oxidation potential of hydrazine and increase the catalytic current. The dependence of the electrocatalytic current on the hydrazine concentration exhibited two linear ranges, 0.1–0.4 μmol/L and 0.7–12.0 μmol/L, with a detection limit of 18.0 nmol/L. Additionally, the simultaneous determination of hydrazine and phe‐nol was investigated using the MBCPE/Fe3O4NPs/DPB electrode. Voltammetric experiments showed a linear range of 100–470 μmol/L and a detection limit of 24.3 μmol/L for phenol, and the proposed electrode was applied to the determination of hydrazine and phenol in water samples.
基金financially supporting this research under Contract No. NSC 102-2221-E-155-076-MY3
文摘An antireflection （AR） coating is fabricated by applying an optimal spin-coating method and a pH-modified SiO2 nanoparticle solution on a cover glass. Because the pH value of the solution will affect the aggregation and dispersion of the SiO2 particles, the transmittance of the AR-treated cover glass will be enhanced under optimal fabricated conditions. The experimental results show that an AR coating fabricated by an SiO2 nano- particle solution of pH 11 enhances the transmittance approximately by 3% and 5% under normal and oblique incident conditions, respectively. Furthermore, the AR-treated cover glass exhibits hydrophobicity and shows a 65% enhancement at a contact angle to bare glass.
