Preparation and characterization of aFGF-loaded chitosan nanoparticles with two different methods for drug delivery applications
Mir HamedHajimiri, SheidaShahverdi, FatemeAtyabi, RassoulDinarvand
Pharmaceutical department, Faculty of Pharmacy, Tehran University of Medical Science, Tehran, Iran.
Purpose
Angiogenic factors for example acidic fibroblast growth factor (aFGF) have great ability to induce angiogenesis for biomedical applications. On the other hand sustainable delivery of therapeutic as well as functional proteins such as growth factors is largely required in the regenerative medicine.1,2
Chitosan is a natural, nontoxic, biodegradable and biocompatible cationic polysaccharide which has considerable interest in tissue engineering and drug delivery systems.2
Nowadays chitosan nanoparticles (NPs) can be prepared by several processes. In this study ionic gelation and poly electrolyte complexation (PEC) methods has been investigated.3
Methods
First chitosan NPs were prepared by ionic gelation of CS with sodium tripolyphosphate (TPP) as anionic polyelectrolyte. For this purpose, CS was dissolved in acetic acid aqueous solution (1mg/ml) and adjusted to pH 5 according to the appropriate pH mentioned for the stability of aFGF. Then aFGF was loaded in a certain concentration.The TPP solution at concentration of 0.5mg/ml was added dropwise to chitosan solution. After ultracentrifugation the chitosan NPs were resuspended in DI water.
In PEC process we used heparin as a polyanion which contains sequences that bind a variety of proteins such as growth factors. Chitosan and heparin were dissolved in acetate buffer (0.1M, pH5.0). NPs were prepared by one-shot addition of heparin to chitosan. After 1 h of stirring, theaFGF was added to NPs in the same concentration. Then the solution was centrifuged and the NPs were resuspended in DI water.
Size, size distribution and zeta potential of the resulted NPs were analyzed by Zetasizer Nano ZS.
The aFGF loading efficiency of NPs was calculated from the following equation:
Results
In ionic gelation method themean particles diameter (114nm) is significantly smaller than PEC method (167nm) (P<0.01). Both methods had acceptable particle size distribution (<0.3).
The zeta potential for PEC process was negative (-14.3) while surface charge for the other method was positive (13).
The Loading efficiency was significantly higher in PEC method (p<0.05) which could be related to aFGF binding sequences on heparin.
This study demonstrated that PEC method for fabricating aFGF loaded chitosan NPs offers more efficient preparation process.
References
[1] K. A. Janes, M. J. Alonso, Journal of Applied Polymer Science, Vol. 88(2003), 2769–2776.
[2] SomnukJarudilokkul†, AnupapTongthammachat, and ViroteBoonamnuayvittaya, Korean J. Chem. Eng., 28(5)(2011), 1247-1251
[3]Yan Sun, Ajun Wan, Journal of Applied Polymer Science, Vol. 105(2007), 552–561
Fig1. Ionic gelation method
Fig2. PEC Method