Shell Click-Crosslinked (SCC) Nanoparticles: A New Methodology for Synthesis and Orthogonal Functionalization
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- 作者：Maisie J. Joralemon ; Rachel K. O'Reilly ; Craig J. Hawker ; and Karen L. Wooley
- 刊名：Journal of the American Chemical Society
- 出版年：2005
- 出版时间：December 7, 2005
- 年：2005
- 卷：127
- 期：48
- 页码：16892 - 16899
- 全文大小：253K
- 年卷期：v.127,no.48(December 7, 2005)
- ISSN：1520-5126
文摘
A new methodology for the preparation of well-defined core-shell nanoparticles was developed,based upon the employment of a multifunctional crosslinker to coincidently stabilize supramolecular polymerassemblies and imbed into the shell unique chemical functionalities. Amphiphilic diblock copolymers ofpoly(acrylic acid)80-b-poly(styrene)90 that had been assembled into micelles and partially functionalizedthroughout the corona with alkynyl groups were utilized as Click-readied nanoscaffolds for the formation ofshell Click-crosslinked nanoparticles (SCCs). Divergently grown dendrimers of the zero, first, second, andthird generations having increasing numbers of azide terminating groups ((N3)2-[G-0], (N3)4-[G-1], (N3)8-[G-2], and (N3)16-[G-3], respectively) were investigated as crosslinkers via Click reactions with the alkynylgroups to form covalent linkages throughout the block copolymer micelle corona, thus forming a crosslinkedshell. The crosslinking reactions were characterized by 1H NMR and IR spectroscopies, differential scanningcalorimetry (DSC), and dynamic light scattering (DLS) measurements. Only the first generation dendrimer((N3)4-[G-1]) possessed a sufficient balance of polyvalency and water solubility to achieve crosslinking andestablish a robust nanostructure. The resulting SCC was further characterized with atomic force microscopy(AFM), transmission electron microscopy (TEM), and analytical ultracentrifugation (AU). The dendriticcrosslinker is important as it also allows for the incorporation of excess functionality that can undergocomplementary reactions. Within the shell of this SCC the remaining azide termini of the dendrimercrosslinker were then consumed in a secondary Click reaction with an alkynyl-functionalized fluorescein toyield a fluorescently labeled SCC that was characterized with DLS, AFM, TEM, AU, UV-vis, and fluorescentmeasurements as a function of pH.