Tunable dual-emitting shell-crosslinked nano-objects as single-component ratiometric pH-sensing materials.
Tunable dual-emitting shell-crosslinked nano-objects as single-component ratiometric pH-sensing materials.
复制标题
可调双发射壳链接的纳米对象作为单组分比率pH-sensing材料。
DOI：
10.1039/c1jm11854d
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发表时间：
2011
影响因子：
--
通讯作者：
Wooley KL
中科院分区：
文献类型：
--
作者：
Lee NS;Sun G;Lin LY;Neumann WL;Freskos JN;Karwa A;Shieh JJ;Dorshow RB;Wooley KL
能够感知环境 pH 值变化的双发射光子纳米物体是基于由两亲性嵌段共聚物组装而成的壳交联胶束而设计的，并与 pH 值不敏感的发色团交联。发色交联剂是四官能化的吡嗪分子，其带有一组末端脂肪胺基团和一组苯胺基胺基团，其表现出对纳米物体的聚丙烯酸壳域的形态依赖性反应性。苯胺基胺基团与纳米物体壳反应的程度会影响低色移（蓝移）。 496 nm 处的荧光强度与 560 nm 处的荧光强度之比取决于溶液的 pH 值。在此，我们报告了对棒状或球形纳米物体的 pH 敏感双发射光物理性质的观察，其壳域为酰胺化反应的发生提供了两个不同的平台——通过添加碳二亚胺或预先安装活化酯基团形成活化酯。我们证明，交联反应的物理操作（形态或颗粒尺寸的变化）或化学操作（活化酯的安装顺序）可导致双发射超过大约 100 倍的微调。生理相关 pH 范围内为 60 nm。具有聚对羟基苯乙烯核的棒状壳交联纳米结构随着pH值的增加而表现出蓝移，而具有聚苯乙烯核和聚环氧乙烷冠的球形壳交联纳米结构随着pH值的降低而表现出蓝移。
Dual-emitting photonic nano-objects that can sense changes in the environmental pH are designed based on shell-crosslinked micelles assembled from amphiphilic block copolymers and crosslinked with pH-insensitive chromophores. The chromophoric crosslinkers are tetra-functionalized pyrazine molecules that bear a set of terminal aliphatic amine groups and a set of anilino amine groups, which demonstrate morphology-dependent reactivities towards the poly(acrylic acid) shell domain of the nano-objects. The extent to which the anilino amine groups react with the nano-object shell is shown to affect the hypsochromic shift (blue-shift). The ratio of fluorescence intensity at 496 nm over that of 560 nm is dependent upon the solution pH. We report, herein, observations on the pH-sensitive dual-emission photophysical properties of rod-shaped or spherical nano-objects, whose shell domains offer two distinct platforms for amidation reactions to occur—through formation of activated esters upon addition of carbodiimide or pre-installation of activated ester groups. We demonstrate that physical manipulations (changes in morphology or particle dimensions) or chemical manipulations of the crosslinking reaction (the order of installation of activated esters) lead to fine tuning of dual-emission over ca. 60 nm in a physiologically relevant pH range. Rod-shaped shell-crosslinked nanostructures with poly(p-hydroxystyrene) core show blue-shift as a function of increasing pH while spherical shell-crosslinked nanostructures with polystyrene core and poly(ethylene oxide) corona exhibit blue-shift as a function of decreasing pH.