文摘
Chitosan-gold hybrid nanospheres were prepared through a direct facile approach that utilized cross-linked compositenanospheres consisting of low-molecular-weight chitosan (LWCS) and ethylenediaminetetraacetic acid (EDTA) asa precursor reaction system. EDTA was employed not only to construct the counterion interaction-based compositenanospheres with the cationic chitosan but also as the reductant for subsequent in situ gold salt reduction within theLWCS-EDTA composite nanospheres. This approach elegantly ensured that each and every nanosphere was loadedwith gold nanoparticles and no nonembedded free gold nanoparticles would exist in the dispersing medium. Moreover,becauseof the noncovalent interaction between LWCS and EDTA, the EDTA reductant can be easily removed fromthe cross-linked nanospheres, and "pure" chitosan-gold hybrid nanospheres can be obtained. The obtained chitosan-gold hybrid nanospheres were found to have a tunable size and good dispersing stability within a wide pH range. Theembedded gold nanoparticles were in the range from several to several tens of nanometers, which may be useful forsensing and imaging. Morphology studies indicated that most of the loaded gold nanoparticles were located in theinterior of the hybrid nanospheres. Taking into account the good biocompatibilities of LWCS, abundant functional(amino) groups in chitosan, and the mild preparation conditions, we find that the chitosan-gold hybrid nanospheresprepared here may have tremendous potential in advanced biomedical applications.