Dually cross-linked supramolecular hydrogels for sensor applications

所提交的项目涉及基于具有超分子主体/客体结构的（水）凝胶的传感器的研究。作为感兴趣的和相关的分析物，特殊的生物标志物（精胺，亚精胺），掺杂物质（N-甲基己胺）和杀菌剂（苯醚甲环唑）进行了鉴定。多年来，（水）凝胶被确立为活性材料。借助于换能器，可以利用作为对刺激的反应的体积变化来产生传感器信号。合适的主体/客体（HG）结构的引入提供了关于所检查的分析物实现高选择性。在所提出的项目理念中，通过将客体分子包含到主体分子中来形成物理相互作用，从而产生交联。由此，主体分子形成拓扑空腔。穿透该空腔并与主体相互作用的分子被概括为客体分子。这两种物质之间形成的相互作用是纯物理的，不是共价的，因此是可逆的。在具有HG交联的“智能”水凝胶中，可能的可结合客体分子的带宽将用于引发凝胶的物质特异性反应。为了实现这一点，也能够与宿主相互作用的外源分子将被递送到HG系统（HG 1）。与主体分子的空腔的非常特殊的相互作用导致另一个HG复合物（HG 2）的竞争形成，导致原始客体从主体空腔排斥。由于这种交换，交联断裂并在水凝胶在（水性）环境中的溶胀中屈服。除了由于在凝胶中包含溶剂而引起的主要溶胀之外，双重交联的水凝胶通过交联度的额外降低而溶胀。虽然几个分子可以充当客体物种，如果它们适合主体空腔，但可能的主体分子的选择更加有限。该项目中特别感兴趣的是环糊精（a-CD和b-CD）以及支柱芳烃（P[5]a和P[6]a）。为了正确检测分析物，主体/客体对的结合常数应低于主体/分析物（HA）对。另一方面，结合常数不能太小，因为这样就不会观察到分析物添加的影响。100是结合常数的合适比值（HA / HG）。在微传感器中，“智能”水凝胶（化学-机械换能器）的溶胀变化将最终由传感器信号中的压阻Si压力传感器（机械-电换能器）产生。

The submitted project deals with the investigation of sensors based on (hydro-)gels having supramolecular host/guest structures incorporated. As interesting and relevant analytes special biomarker (spermine, spermidine), doping substances (N-methyl hexane amine) and fungicides (difenoconazole) were identified. (Hydro-)gels are established as active materials since some years. With the aid of a transducer the volume change as reaction to a stimulus can be utilized to generate a sensor signal. The incorporation of suitable host/guest (HG) structures offer to achieve a high selectivity regarding the examined analyte. In the presented project idea the cross-linking yields from the formation of physical interactions by inclusion of the guest molecule into the host molecule. Hereby, the host molecule forms a topological cavity. Molecules that penetrate this cavity and interact with the host are summarized as guest molecules. The kind of interaction being formed between the two species is purely physical and not covalent and hence, reversible. In “intelligent” hydrogels with HG cross-linking the band width of possible bindable guest molecules will be used to initiate a substance specific reaction of the gel. To achieve this a foreign molecule that is also able to interact with the host will be delivered to the HG system (HG1). The very particular interaction with the cavity of the host molecule lead to a competing formation of another HG complex (HG2) resulting in a repulsion of the original guest from the host cavity. Due to this exchange the cross-link breaks and yields in a swelling of the hydrogel in an (aqueous) environment. In addition to the primary swelling due to inclusion of solvent in the gel dually cross-linked hydrogels swells by additional decrease of the degree of cross-linking. While several molecules can act as guest species if they fit into the host cavity the choice of possible host molecules is more limited. Of particular interest within this project are cyclodextrins (a-CD and b-CD) as well as the pillar arenes (P[5]a and P[6]a). For a proper detection of the analyte the host/guest pair shall have a lower binding constant than the host/analyte (HA) pair. On the other side the binding constant must not be too small since then no effect with analyte addition will be observed. 100 is expected to be a proper ratio of the binding constants (HA / HG). In a micro sensor the swelling change of an “intelligent” hydrogel (chemo-mechanical transducer) will finally result by a piezo-resistive Si pressure sensor (mechano-electric transducer) in a sensor signal.