These findings indicate that this novel nano-delivery system can be used to carry A to the brain. novel targeted nano-vaccine delivery system can be used as a carrier for A. This system will further research of peptide vaccines for AD. test. A two-sided probability SL 0101-1 level of 0.05 was defined as statistically significant. All calculations were made using statistical software (SPSS 11.0). RESULTS Characterization of Nanoparticles by TEM and Photon Correlation Spectroscopy All nanoparticles analyzed by TEM were well-separated, roughly spherical structures with uniform SL 0101-1 particle size distribution as shown in Fig.?1. The average diameter was 15.23??10.97?nm as measured by photon correlation spectroscopy (PCS). Open in a separate window Fig. 1 Nanoparticles analyzed by TEM AE of Nanoparticles Loaded with IF-A The AE for IF-A with the nanoparticles was determined SL 0101-1 as shown in Fig.?2. The AE was 78.4%, favorable for a vaccine. Open in a separate window Fig.?2 AE for IF-A with the nanoparticles Serum and Brain IgG Against A42 We evaluated the immunogenicity of NP-IF-A and KLH-IF-A by ELISA. Animals immunized with NP-IF-A and KLH-IF-A had significantly more IgG against A42 in serum than controls, especially after the fourth immunization (Fig.?3). Although the IgG titer against A42 in animals immunized with NP-IF-A was higher than that of those immunized with KLH-IF-A, the result was not a statistically significant difference. There was a lower titer of IgG against A42 in the brain than in plasma after the last immunization (Fig.?4). Open in a separate window Fig.?3 IgG against A42 in animals immunized with NP-IF-A and KLH-IF-A and controls Open in a separate window Fig.?4 Titer of IgG against A42 in the Il1a brain and in plasma after the last immunization Brain Uptake of the NP-IF-A We labeled IF-A with FITC and evaluated the brain uptake efficiency of the NP-IF-A. We compared the IF-A amount in the brain with that in blood and the IF-A amount in the brain in the experimental group with that in the control group by fluorescence spectrophotometry and fluorescent microscopy. The uptake efficiencies of IF-A in the experimental group and the control group were 80.6% and 20.7%, respectively. There was a significant difference between the two groups, evaluated by fluorescent spectrophotometer ( em p /em ? ?0.01) (Figs.?5 and ?and66). Open in a separate window Fig.?5 Uptake efficiencies of IF-A in the experimental group and SL 0101-1 the control group Open in a separate window Fig.?6 Uptake efficiencies of IF-A in the experimental group and the control group DISCUSSION Chitosan has been used as a safe excipient in drug formulations for over two decades (10). Its lack of toxicity and allergenicity and its biocompatibility, biodegradability, and bioactivity make SL 0101-1 it a very attractive substance for diverse applications in pharmaceutical and medical fields. It has been used for both systemic and local delivery of drugs and vaccines (11,12). Glutaraldehyde is somewhat toxic, but glutaraldehyde-crosslinked chitosan microspheres have been extensively investigated for drug delivery (13C15), and different crosslinking methods (i.e., sulphuric acid and heat treatment) should be explored. Different preparation methods, types of chitosan, and different crosslinking methods result in nanoparticle size differences (16). Particle size measurements depend on the detection method (17). The discrepancy in the sizes of nanoparticles based on PCS and TEM may be due to the fact that the dynamic light scattering method gives the hydrodynamic diameter rather than the actual diameter of nanoparticles. A comparison of the particle sizes determined using other techniques would be valuable. A vaccine can promote humoral immunity and production of antibodies against A, reducing the A burden and behavioral impairment in AD models (18,19). Several researchers have reported that chitosan has the ability to regulate the functions of cellular immunity (20C22) and macrophages (23,24). However, there have been no analyses of the effect of chitosan on humoral immunity. In.