Nanomedicine Research Journal

69-78

Authors: Amirali Abbasi; Jaber Jahanbin Sardroodi

Objective(s): First-principles calculations have been carried out to investigate the interaction of aspirin molecule with nitrogen-doped TiO2 anatase nanoparticles using the density functional theory method in order to fully exploit the biosensing capabilities of TiO2 particles. Methods: For this purpose, we have mainly studied the adsorption of the aspirin molecule on the fivefold coordinated titanium atom site of the TiO2 nanoparticles because of the more reactivity of this site in comparison with the other sits. The complex systems consisting of the aspirin molecule positioned toward the undoped and nitrogen-doped nanoparticles have been relaxed geometrically. Results: The obtained results include structural parameters such as bond lengths and energetic of the systems. The electronic structure and its variations resulting from the adsorption process, including the density of states, molecular orbitals and the Mulliken charge transfer analysis have been discussed. We found that the adsorption of aspirin molecule on the nitrogen-doped TiO2 nanoparticles is energetically more favorable than the adsorption on the undoped ones. Conclusions: These results thus provide a theoretical basis and overall understanding on the interaction of TiO2 nanoparticles with aspirin molecule for applications in modeling of efficient nanomedicine carriers, biosensors and drug delivery purposes.

84-89

Authors: Hossein Khosravi; Armita Mahdavi; Faezeh Rahmani; Ahmad Ebadi

Objective(s): In this study we evaluate the impact of the different aspects of Gold Nano-Particles (GNPs) on the target absorptive Dose Enhancement Factor (DEF) during external targeted radiotherapy with photon beams ranging from kilovolt to megavolt energies using Monte Carlo simulation. Methods: We have simulated the interaction of photon beams with various energies of radiation using water solution containing GNPs to be located in a tumor region and used MCNP5 code for Initially, the water phantom in which a tumor dimensions of 1 × 1 × 1 cm3 was defined as the target, contained simulated GNPs. Then, themacroscopic DEF of GNPs of different sizes, including 15, 50, and 100 nm, had been calculated at the target area with a fixed concentration of 7 mg/g during external beam radiotherapy with single-energy photon beams ranging from keV to MeV. Results: The tumor DEFs in the presence of GNPs were obtained 1.69-2.66and 1.08-1.10 for keV and MeV beams, respectively. The highest DEF was achieved by photon energy of 50 keV. By increasing the size of the GNPs, the tumor dose factor raised too. Conclusions: The factors calculated for enhancing the target dose of GNPs were in good agreements with previous studies based on keV photon energies. For MeV photon energies, after a reduction in the boundary between the two areas of water and the solution containing GNPs, the dose factor was enhanced to its maximum value for 2 and 6 MeV photon beams at the depths of 2.6 and 5.6 cm, respectively.

97-106

Authors: Simin Seifirad; Hasan Karami; Shadab Shahsavari; Farzad Mirabasi; Farid Dorkoosh

Objective(s): Nanoparticles (NPs) are known for their specific accumulation in the inflamed tissues of the colon and thus allow a selective delivery to the site of inflammation with minimum adverse effects. The main objective of this work is to attain mesalamine loaded chitosan nanoparticles as a carrier for oral delivery. Methods: In this study, mesalamine loaded chitosan nanoparticles were prepared using an ionic gelation method. Experimental design Box-Behnken response surface methodology was used for the optimization of the nanoparticles. The nanoparticles size and gelation process of the polymeric nano-drug controlled release system depends on several variables including the concentration ratio of chitosan-TPP, concentration of mesalamine, concentration of chitosan solution and pH of the solution with optimum conditions of 2.3, 0.02 mg/ml, 0.1 mg/ml and 4.5, respectively. Results: The mean particle size of the synthesized nanoparticles was ranging from 53.9 to 322.8 nm using a dynamic light scattering (DLS) technique. Moreover, the morphology of the prepared nanoparticles was observed by scanning electron microscopy (SEM). Also, characterization of the chitosan-mesalamine nanoparticles was performed by FT-IR spectrophotometer for specifying the chemical structure of nanoparticles molecules and differential scanning calorimetry (DSC) for studying thermal behavior. Drug release profile and the amount of the loaded drug were also monitored by UV-Vis spectroscopy. Conclusions: Drug released showed that the release profile of mesalamine loaded nanoparticles was in a slow manner and no initial rapid release (burst effect) was illustrated.

112-121

Authors: Minoo Sadri; Aref Mohammadi; Hassan Hosseini

Objective(s): In this work, electrospun nanofibers were explored as drug delivery vehicles using tetracycline as a model drug. Nanocomposite fibers including chitosan (CS)/poly (ethylene oxide) (PEO) and antibiotic were successfully prepared using electrospinning. CS blended with PEO considering a weight ratio of (90/10), and then, nanofibrous samples were successfully electrospun from their aqueous solutions. Afterwards, tetracycline was added to these samples for producing wound dressing materials. Methods: Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used for the evaluation of morphology and biodegradability studies of CS/PEO blend nanofibrous. The kinetic and drug release mechanism of drug-loaded electrospun samples were also investigated by ultraviolet-visible spectrophotometry (UV-Vis) and the appropriate model was proposed for prediction of drug release. Results: The results have indicated that the addition of tetracycline as much as 0.4%wt brings about the best nanofiber. The results of stability study of composite nanofibrous showed that the samples containing the active ingredient of tetracycline have maintained their structure after 24 h in the vicinity of acetate buffer solution. The model of antibiotic release from the nanofiber was examined and it was found that the release mechanism can be described as Fickian diffusion model. According to this model, the kinetic degree of the drug release is around 0.41. Conclusions: The study of drug release from this nanofiber showed that the liberation level is relatively high during the early hours and over time, high amounts of the drug diffuse from the inside of nanofiber into the aqueous environment.