Hybrid Nanospheres Formed by Intermixed Double-Hydrophilic Block Copolymer Poly(ethylene oxide)-block-poly(2-ethyloxazoline) with High Content of Metallacarboranes

作者：Dordovic Vladimir; Uchman Mariusz; Prochazka Karel; Zhigunov Alexander; Plestil Josef; Nykanen Antti; Ruokolainen Janne; Matejicek Pavel^*

来源：Macromolecules, 2013, 46(17): 6881-6890.

DOI：10.1021/ma4013626

In search for biocompatible hydrophilic polymers suitable for preparation of delivery systems of boron cluster compounds with high loading capacity, we studied the interaction of metallacarborane sodium [3-cobalt(III) bis(1,2-dicarbollide)] with poly(2-ethyloxazoline) (PEOX) and with a double-hydrophilic block copolymer poly(ethylene oxide)-block-poly(2-ethyloxazoline) (PEO-PEOX) in aqueous solutions by a combination of scattering, microscopy, spectroscopy, and thermochemistry techniques. The paper is a contribution to our long-time study of novel hybrid nanostructures based on hydrophilic polymer-metallacarborane complexes. PEOX homopolymer interacts with metallacarborane, resulting in a water-soluble, negatively charged complex. In the case of diblock copolymer PEO-PEOX, both blocks interact with metallacarborane via dihydrogen bonds and participate in the formation of hybrid gel-like nanostructures in 0.1 M NaCl aqueous solutions, which are unique as compared to other boron cluster-containing polymeric systems. The stable spherical nanoparticles with high metallacarborane content do not adopt core/shell structure, which has been observed for other PEO-containing double hydrophilic block copolymers [Macromolecules 2009, 42, 4829], but the nanospheres are homogeneous. They contain intermixed PEO and PEOX blocks, which are cross-linked by metallacarborane molecules. The size of the nanospheres depends on a preparation protocol, while their inner structure does not. Besides the detailed study on PEO-PEOX/metallacarborane system, a high application potential of PEO-PEOX complexes with several metallacarborane-based drugs is also shown. The study clearly demonstrates that PEOX is suitable polymer for designing novel hybrid nanostructures.

• 出版日期2013-9-10