ABSTRACT
The method of optogenetics is a new light-control ccll technology which has developed rapidly in the field of neuro- science in the past decade. This technique is also called "a new technology destined to win the Nobel Prize in the 21st century". The bioengineering technology integrates many disciplines of optics, genetics, computer science, genetic engineering, cell biology, clectrophysiology and more. This new multi-disciplinary cross-disciplinary new technology has greatly promoted the development of neuroscience, extending to animal behavior, clinical medicine, molecular biology, cell biology and many other fields. Animal behavior research is about the study of the function, mechanism, development and evolution of animal behavior, which plays an important role in the development of neuro- science. This article describes the specific process and characteristics of optogenetics, and its application in animal behavior research, aiming at a brief review of the latest research progress in optogenetics technology.
ABSTRACT
Photo-sensitive reactive oxygen species (ROS) responsive liposomes loaded with 1,4,8,11,15, 18,22,25-octabutoxypalladium phthalocyanine[PdPC(OBu)8] and doxorubicin hydrochloride (DOX) (LPD) were prepared by (NH4)2SO4-gradient method. LPD was characterized with transmission electron microscopy (TEM), dynamic light scattering particle size, zeta potentials, photo-sensitive ROS-responsive DOX release behaviors and the serum stability in vitro. LPD cytotoxicity, DOX uptake and singlet oxygen production in MCF-7 cells were evaluated. The results showed that the particle size of LPD was (169.3 ±1.2) nm, PDI of LPD was 0.198 ±0.003 and zeta potentials of LPD was (-39.8 ±0.8) mV. The accumulated release of DOX reached 95.5% in 5 min under 730 nm laser irradiation (300 mW·cm-2). The DOX uptake of liposome was increased and 1O2 was generated. The half inhibition concentration (IC50) of DOX in LPD with irradiation group was decreased by 85.7% and no irradiation group was decreased by 67.9% compared with free DOX group in MCF-7 cells. Therefore, photo-sensitive ROS-responsive liposomes would be a promising drug delivery system for tumor therapy.
ABSTRACT
This study was aimed to build a new photo-sensitive co-delivery liposomes which combine photodynamic therapy with chemotherapy to reverse drug resistance of breast cancer. Photodynamic photosen-sitizer chlorin e6 trimethyl ester (Ce6tM) and chemotherapeutic drug doxorubicin hydrochloride (DOX) were loaded into the liposomes (liposomes loaded with Ce6tM and DOX, CDL) by thin-film hydration extrusion and ammonium sulfate active loading methods. CDL was characterized with cryo-transmission electron microscopy (Cryo-TEM), dynamic light scattering particle size, zeta potentials and photo-sensitive DOX release behaviors in vitro. CDL cytotoxicity, singlet oxygen production, DOX accumulation, intracellular ATP level and cell cycle analysis in MCF7/ADR cells were evaluated. Finally, the tissue distribution of DOX and antitumor effects of CDL in BALB/c-nu nude mice bearing MCF7/ADR tumor were investigated. The results showed that the particle size of obtained CDL was 90.7 ± 1.1 nm and distributed uniformly. CDL possessed outstanding properties of photo-sensitive drug release profile. The accumulated release of DOX reached (96.52 ± 0.11)% in 2 min under 671 nm laser irradiation (2 W·cm-2). Interestingly, DOX in CDL could maintain rapid release after 671 nm laser irradiation with low power and short time (15 s, 0.25 W·cm-2). This phenomenon was caused by oxidation of unsaturated phospholipids in CDL under 671 nm laser irradiation and had nothing to do with the slightly elevated temperature. Photo-sensitive drug release behavior contributed to increased DOX accumulation in MCF7/ADR cells. The half inhibition concentration (IC50) of DOX in CDL laser group in MCF7/ADR cells was decreased by 601.9-fold compared with no laser group, which could be related to increased accumulation of DOX, decreased ATP levels and cell cycle arrest in MCF7/ADR cells. With the help of CDL, DOX accumulation in tumor was increased and in cardiac toxicity was reduced in vivo. CDL laser group showed a good anti-tumor effect. The tumor inhibition rate was (94.7 ± 6.2)%. These results suggest that CDL has a promising potential in reversing drug resistance of breast cancer.