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Insulin aggregation and amyloid fibril formation accelerated by the presence of the PVP-coated nanoparticles
S218
Abstracts
d Health Department, Mashhad University of Medical Scienses, Mashhad, Iran E-mail addresses: [email protected] (N. Sobhani), [email protected] (A. Sazgarnia), [email protected] (N. Naghavi), [email protected] (O. Rajabi), [email protected] (S. Akhlaghi)
Introduction: Photodynamic therapy (PDT) is a therapeutic method using a photosensitizer that is activated by proper wavelength of light and molecular oxygen. Effective delivery of photosensitizer to target tumor cells that causes minimal damage to healthy cells is an important requirement in photodynamic therapy of cancer. Protoporphyrin IX (PpIX) induced endogenously by 5aminolevulinic acid can be used as a photosensitizer to destroy photodynamically tumor cells. In this study biocompatible gold nanoparticles were used as a vehicle to deliver 5-aminolevulinic acid (5ALA) in intratumoral injection for selective and efficient in vivo photodynamic therapy of CT26 tumor model. Accumulation time in equivalent concentration of 5ALA and 5ALA-AU was compared with each other. Results: PpIX accumulation achieved the peak level at 3 and 5 h after intratumoral injection of 5ALA-AU and 5ALA, respectively and was completely eliminated within 24 h. Conclusions: It seems that 5ALA conjugated gold nanoparticles are not efficient on decrease of incubation time of 5ALA. Keywords: Photodynamic therapy, Protoporphyrin IX, Gold nanoparticle, 5-ALA, Intratumoral injection
doi:10.1016/j.clinbiochem.2011.08.968
Poster – [A-10-677-1] In vivo evaluation of biochemical efficacy of prepared insulin-loaded nanoliposomes for oral delivery Amir Gharib, Zohreh Faezizadeh Department of Laboratory Sciences, Islamic Azad University, Brojerd, Iran E-mail addresses: [email protected] (A. Gharib), [email protected] (Z. Faezizadeh) Introduction: The oral insulin delivery is the most favorite route for insulin adminstration. The aim of this study was to generate a new chitosan coated insulin nanoliposomes and then, the physiological efficacy of insulin-loaded nanoliposomes was determined after oral administration in diabetic rabbits. Methods: Nanoliposomes encapsulated insulin with negative surface charge prepared by reverse phase evaporation method. For prepared nanoliposomes lecithin, cholesterol, cetyl-diphosphate and β-cyclodexterin were used. Then, nanoliposomes were coated by means of incubation with the chitosan solution. The encapsulation efficiency of prepared nanoliposomes was measured by spectrophotometry technique after dissolution of the nanoparticles. The hypoglycemic efficacies of chitosan-coated insulin nanoliposomes were investigated by monitoring the blood glucose level after oral administration to diabetic rabbits. Results: Insulin entrapment efficacy for preparation of new formulated nanoliposomes were significantly (p < 0.05) higher than those of another formulations, respectively. The in vivo result clearly indicated that the insulin-loaded nanoliposomes could effectively reduce the blood glucose level in diabetic rabbits from 250 ± 0.75 mg/dl to 125 ± 0.98 mg/dl at 4 h. Conclusion: The results clearly suggest that prepared nanoliposomes may be considered as a good candidate for oral insulin delivery.
Keywords: Chitosan, Insulin, Nanoliposome, Entrapment efficacy doi:10.1016/j.clinbiochem.2011.08.969
E. Poster — [A-10-719-1] Insulin aggregation and amyloid fibril formation accelerated by the presence of the PVP-coated nanoparticles Ostadi Hassana, Shariat Sajjada, Morshedi Dinab, Nemat-Gorgani Mohsena a Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran b National Institute of Genetic Engineering and Biotechnology (NIGEB), Shahrak-e-Pajoohesh, 15th Km, Tehran-Karaj Highway, Tehran, Iran E-mail addresses: [email protected] (O. Hassan), [email protected] (S. Sajjad), [email protected] (M. Dina), [email protected] (N.-G. Mohsen) Introduction: Amyloid fibrils are highly ordered aggregated states of peptides and proteins, and appear in a variety of diseases. Nanoparticles may significantly alter the rate of protein aggregation and fibrillation as well as offering therapeutic opportunities for their treatment. Their potential to induce protein fibrillation is a function of both the nanoparticle surface charge and its large surface to volume ratio. The mechanism proposed in studies of nanoparticle–protein fibrillation suggests that nanoscale surfaces can act as platforms for protein association. For proteins directly or indirectly bound to nanoparticles, this association can induce some changes in protein structure, and as with low pH or high temperature, proteins may unfold and produce structures more likely to form fibrils and aggregates. Material and method in the present study: We investigated the effect of PVP-coated nanoparticles having a nominal size of 50 nm on the aggregation and fibrillation of insulin. The conditions employed for amyloid formation were pH 7.2 and 37 °C with agitation at a fixed speed. Results: The formation of amyloid fibrils and amorphous aggregates, and the effects of PVP-coated nanoparticles were verified through some specific methods of amyloid detection such as atomic force electron microscopy, Congo red binding, thioflavine-T fluorescence, and circular dichroism. Our results suggested that the process is accelerated by the presence of the nanoparticles. Conclusion: The present study may open interesting directions for work on fibrillation-related diseases and for the discovery of agents (e.g. nanoparticles) which may interfere with such processes. Keywords: Insulin, PVP-coated nanoparticles, Amyloid formation, Aggregation, Amyloid diseases doi:10.1016/j.clinbiochem.2011.08.970
Poster – [A-10-721-1] Assessment of the effects of biochemical factors on extracellular biosynthesis of silver nanoparticles by the mycelia extracts of some fungal strains Parastoo Pourali, Majid Baseri Salehi, Sima Afsharnezhad, Javad Behravan, Hassan Alavi, Hosseini B.B. Ashraf Section of Microbiology, Department of Biology, Faculty of Science, Fars Science and Research Branch, Islamic Azad University, Shiraz, Iran E-mail address: [email protected] (P. Pourali) Introduction: In this study, the extracellular biosynthesis of silver nanoparticles was examined and characterized from extracellular components of some fungal strains that were isolated from the soil. After that the effect of biochemical parameters was examined on nanoparticles production.
Abstracts
d Health Department, Mashhad University of Medical Scienses, Mashhad, Iran E-mail addresses: [email protected] (N. Sobhani), [email protected] (A. Sazgarnia), [email protected] (N. Naghavi), [email protected] (O. Rajabi), [email protected] (S. Akhlaghi)
Introduction: Photodynamic therapy (PDT) is a therapeutic method using a photosensitizer that is activated by proper wavelength of light and molecular oxygen. Effective delivery of photosensitizer to target tumor cells that causes minimal damage to healthy cells is an important requirement in photodynamic therapy of cancer. Protoporphyrin IX (PpIX) induced endogenously by 5aminolevulinic acid can be used as a photosensitizer to destroy photodynamically tumor cells. In this study biocompatible gold nanoparticles were used as a vehicle to deliver 5-aminolevulinic acid (5ALA) in intratumoral injection for selective and efficient in vivo photodynamic therapy of CT26 tumor model. Accumulation time in equivalent concentration of 5ALA and 5ALA-AU was compared with each other. Results: PpIX accumulation achieved the peak level at 3 and 5 h after intratumoral injection of 5ALA-AU and 5ALA, respectively and was completely eliminated within 24 h. Conclusions: It seems that 5ALA conjugated gold nanoparticles are not efficient on decrease of incubation time of 5ALA. Keywords: Photodynamic therapy, Protoporphyrin IX, Gold nanoparticle, 5-ALA, Intratumoral injection
doi:10.1016/j.clinbiochem.2011.08.968
Poster – [A-10-677-1] In vivo evaluation of biochemical efficacy of prepared insulin-loaded nanoliposomes for oral delivery Amir Gharib, Zohreh Faezizadeh Department of Laboratory Sciences, Islamic Azad University, Brojerd, Iran E-mail addresses: [email protected] (A. Gharib), [email protected] (Z. Faezizadeh) Introduction: The oral insulin delivery is the most favorite route for insulin adminstration. The aim of this study was to generate a new chitosan coated insulin nanoliposomes and then, the physiological efficacy of insulin-loaded nanoliposomes was determined after oral administration in diabetic rabbits. Methods: Nanoliposomes encapsulated insulin with negative surface charge prepared by reverse phase evaporation method. For prepared nanoliposomes lecithin, cholesterol, cetyl-diphosphate and β-cyclodexterin were used. Then, nanoliposomes were coated by means of incubation with the chitosan solution. The encapsulation efficiency of prepared nanoliposomes was measured by spectrophotometry technique after dissolution of the nanoparticles. The hypoglycemic efficacies of chitosan-coated insulin nanoliposomes were investigated by monitoring the blood glucose level after oral administration to diabetic rabbits. Results: Insulin entrapment efficacy for preparation of new formulated nanoliposomes were significantly (p < 0.05) higher than those of another formulations, respectively. The in vivo result clearly indicated that the insulin-loaded nanoliposomes could effectively reduce the blood glucose level in diabetic rabbits from 250 ± 0.75 mg/dl to 125 ± 0.98 mg/dl at 4 h. Conclusion: The results clearly suggest that prepared nanoliposomes may be considered as a good candidate for oral insulin delivery.
Keywords: Chitosan, Insulin, Nanoliposome, Entrapment efficacy doi:10.1016/j.clinbiochem.2011.08.969
E. Poster — [A-10-719-1] Insulin aggregation and amyloid fibril formation accelerated by the presence of the PVP-coated nanoparticles Ostadi Hassana, Shariat Sajjada, Morshedi Dinab, Nemat-Gorgani Mohsena a Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran b National Institute of Genetic Engineering and Biotechnology (NIGEB), Shahrak-e-Pajoohesh, 15th Km, Tehran-Karaj Highway, Tehran, Iran E-mail addresses: [email protected] (O. Hassan), [email protected] (S. Sajjad), [email protected] (M. Dina), [email protected] (N.-G. Mohsen) Introduction: Amyloid fibrils are highly ordered aggregated states of peptides and proteins, and appear in a variety of diseases. Nanoparticles may significantly alter the rate of protein aggregation and fibrillation as well as offering therapeutic opportunities for their treatment. Their potential to induce protein fibrillation is a function of both the nanoparticle surface charge and its large surface to volume ratio. The mechanism proposed in studies of nanoparticle–protein fibrillation suggests that nanoscale surfaces can act as platforms for protein association. For proteins directly or indirectly bound to nanoparticles, this association can induce some changes in protein structure, and as with low pH or high temperature, proteins may unfold and produce structures more likely to form fibrils and aggregates. Material and method in the present study: We investigated the effect of PVP-coated nanoparticles having a nominal size of 50 nm on the aggregation and fibrillation of insulin. The conditions employed for amyloid formation were pH 7.2 and 37 °C with agitation at a fixed speed. Results: The formation of amyloid fibrils and amorphous aggregates, and the effects of PVP-coated nanoparticles were verified through some specific methods of amyloid detection such as atomic force electron microscopy, Congo red binding, thioflavine-T fluorescence, and circular dichroism. Our results suggested that the process is accelerated by the presence of the nanoparticles. Conclusion: The present study may open interesting directions for work on fibrillation-related diseases and for the discovery of agents (e.g. nanoparticles) which may interfere with such processes. Keywords: Insulin, PVP-coated nanoparticles, Amyloid formation, Aggregation, Amyloid diseases doi:10.1016/j.clinbiochem.2011.08.970
Poster – [A-10-721-1] Assessment of the effects of biochemical factors on extracellular biosynthesis of silver nanoparticles by the mycelia extracts of some fungal strains Parastoo Pourali, Majid Baseri Salehi, Sima Afsharnezhad, Javad Behravan, Hassan Alavi, Hosseini B.B. Ashraf Section of Microbiology, Department of Biology, Faculty of Science, Fars Science and Research Branch, Islamic Azad University, Shiraz, Iran E-mail address: [email protected] (P. Pourali) Introduction: In this study, the extracellular biosynthesis of silver nanoparticles was examined and characterized from extracellular components of some fungal strains that were isolated from the soil. After that the effect of biochemical parameters was examined on nanoparticles production.