Preparation and characterization of m PEG grafted chitosan micelles as 5-fluorouracil carriers for effective anti-tumor activity

The objective of this study was to investigate the potential of methoxy polyethylene glycol（m PEG）grafted chitosan（m PEG-g-CS） to be used as a drug carrier. m PEG-g-CS was successfully synthesized by one-step method with formaldehyde. The substitution degree of m PEG on chitosan was calculated by elemental analysis and was found to be（3.23 0.25）%. m PEG-g-CS self-assembled micelles were prepared by ultrasonic method with the controlled size of 178.5–195.1 nm and spherical morphology. Stable dispersion of the micelles was formed with the zeta potential of 2.3–30.2 m V. 5-Fluorouracil（5-FU）, an anticancer chemotherapy drug, was used as a model drug to evaluate the efficiency of the new drug delivery carrier. The loading efficiency of 5-FU was（4.01 0.03）%, and the drug-loaded m PEG-g-CS self-assembled micelle showed a controlled-release effect. In summary, the m PEG-g-CS self-assembled micelle is proved to be a promising carrier with controlled particle size and controlled-release effect. Therefore, it has great potential for the application as 5-FU carriers for effective anti-tumor activity.

Nanoparticle structure transformation of mPEG grafted chitosan with rigid backbone induced by a-cyclodextrin

This paper presented an interesting nanoparticle-based drug delivery system with morphology transition behavior depending on the content of exposed PEG chain on the particle surface, which is adjustable by addition of different amount of cyclodextrin(α-CD). The effect of α-CD inclusion to the self-assembly behavior of methoxy polyethylene glycol(mPEG) grafted chitosan(CS) was studied. The results showed that the mPEG grafted chitosan(mPEG-g-CS) forms self-assembled nanoparticles with either micelle or hollow sphere morphology depending on the ratio of α-CD to mPEG, as characterized by atomic force microscopy(AFM), transmission electron microscopy(TEM), and X-ray diffraction(XRD). Their sizes and zeta potential increased from 257.6 nmto 768.2 nm and from +4.5 mV to +11.6 mV, respectively, with the increasing amount of α-CD. The correlation between zeta potential and particle size of α-CD/mPEG-g-CS nanoparticles indicated varied PEG density on surface of nanoparticles. Based on the above experimental observations, a likely mechanism for the morphological transition of the rod-coil graft copolymer mPEG-g-CS was proposed.

MUC1 vaccines usingβ-cyclodextrin grafted chitosan(CS-g-CD)as carrier via host-guest interaction elicit robust immune responses

We construct MUC1 vaccines usingβ-cyclodextrin grafted chitosan(CS-g-CD)as carrier via host-guest interaction.These vaccines based on non-covalent assembling can provoke robust immune responses,including high level of specific antibodies and cytokines.The induced antibodies can specifically recognize tumor cells and mediate cytotoxicity against tumor cells.These results indicate that CS-g-CD with strong immunostimulatory activities can be a straightforward platform for peptide-based vaccine construction.