10 research outputs found
About the sterilization of chitosan hydrogel nanoparticles
In the last years, nanostructured biomaterials have raised a great interest as platforms for delivery of drugs, genes, imaging agents and for tissue engineering applications. In particular, hydrogel nanoparticles (HNP) associate the distinctive features of hydrogels (high water uptake capacity, biocompatibility) with the advantages of being possible to tailor its physicochemical properties at nano-scale to increase solubility, immunocompatibility and cellular uptake. In order to be safe, HNP for biomedical applications, such as injectable or ophthalmic formulations, must be sterile. Literature is very scarce with respect to sterilization effects on nanostructured systems, and even more in what concerns HNP. This work aims to evaluate
the effect and effectiveness of different sterilization methods on chitosan (CS) hydrogel nanoparticles. In addition to conventional methods (steam autoclave and gamma irradiation), a recent ozone-based method of sterilization was also tested. A model chitosan-tripolyphosphate (TPP) hydrogel nanoparticles (CS-HNP), with a broad spectrum of possible applications was produced and sterilized in the absence and in the presence of protective sugars (glucose and mannitol). Properties like size, zeta potential, absorbance, morphology,
chemical structure and cytotoxicity were evaluated. It was found that the CS-HNP degrade by autoclaving and that sugars have no protective effect. Concerning gamma irradiation, the formation of agglomerates was observed, compromising the suspension stability. However, the nanoparticles resistance increases considerably in the presence of the sugars. Ozone sterilization did not lead to significant physical adverse effects, however, slight toxicity signs were observed, contrarily to gamma irradiation where no detectable changes on cells were found. Ozonation in the presence of sugars avoided cytotoxicity. Nevertheless, some chemical alterations were observed in the nanoparticles.info:eu-repo/semantics/publishedVersio
UV-Vis.
<p>Spectra of: A) Irradiated CS-HNP sample—the inset shows the sediment formation after irradiation, B) Irradiated CS-HNP in presence of Glucose 5%, C) Irradiated Glucose 5% solutions, D) CS-HNP in presence of Mannitol 5%, E) Irradiated Mannitol 5% solutions.</p
Zetasizer GI.
<p>Data for the irradiated CS-HNP suspensions: A- Average particle size, B- PDI and C- Zeta potential. Error bars correspond to standard deviations.</p
Zetasizer.
<p>Data for the autoclaved (100°C) CS-HNP suspensions: A- Particle counts, B- Average size distribution, C- PDI. Error bars correspond to standard deviations. (n ≥ 3).</p
CS-HNP physico-chemical characteristics over time.
<p>CS-HNP physico-chemical characteristics over time.</p
Zetasizer data for the ozonated CS-HNP suspensions.
<p>A- Average particle size B- PDI, C- Zeta potential. Samples containing glucose and mannitol were only exposed to 8P and 10P. Error bars correspond to standard deviations.</p
Sterility and cytotoxicity tests results.
<p>Sterility and cytotoxicity tests results.</p