Interfacing semiconductor nanocrystals and coordination compounds for the multimodal detection of biological targets

半导体纳米晶体是一种开发得非常充分的材料，在光电子学、能量转换和催化等领域的应用日益突出。与此同时，无机配位化合物作为治疗和诊断试剂在生物医学领域也得到了广泛的应用。在配位化学中，合理选择配体，使金属中心周围的配位球发生变化，可以形成能够结合和/或与生物相关分子相互作用的加合物。分子配位化合物与半导体纳米晶体的结合导致混合材料的形成，其中纳米晶体的固有特性可以受到配位化合物的存在的影响，并且进一步通过后者与生物靶标的结合和/或相互作用来影响。半导体金属卤化物钙钛矿纳米晶体（化学计量ABX3）最近已经成为大量研究的来源，部分原因是它们具有高光致发光量子产率和窄带发射，加上低成本和相对容易的合成。最近，这些纳米晶体表面覆盖配体的关键修饰导致了这些材料性质的快速和重大进展。该团队的研究旨在利用钙钛矿纳米晶体表面基团的模块化，与定制的生物活性配位化合物形成界面。由此产生的混合材料将用作具有挑战性的生物目标的多模态传感器。主要模式涉及光电化学响应，其中输入（可见光激发）和输出（电化学响应）信号是去耦的，从而导致检测的显着限制。传统的光致发光将作为一种补充方式进行探索，其中表面配位化合物（有或没有目标结合）之间的能量转移等机制将提供另一种检测途径。通过这项工作获得的经验教训有望促进对半导体纳米晶体界面能量迁移过程的基本理解，为这些系统作为生物传感器的未来设计提供信息，也可作为能量转换和催化的平台材料。

Semiconductor nanocrystals are well-explored materials that have risen to prominence in applications ranging from optoelectronics, energy conversion, and catalysis. Concomitantly, inorganic coordination compounds have been extensively exploited as both therapeutic and diagnostic agents in biomedicine. In coordination chemistry, variation of the coordination sphere around a metal center with judiciously selected ligands can lead to the formation of adducts that are capable of binding and/or interacting with biologically relevant molecules. A marriage of molecular coordination compounds with semiconductor nanocrystals leads to the formation of hybrid materials where the intrinsic properties of the nanocrystals can be influenced by the presence of the coordination compounds, and further still through the binding and/or interaction of the latter with a biological target. Semiconductor metal halide perovskite nanocrystals (with the stoichiometry ABX3) have been the source of a tremendous number of investigations recently, owing in part to their high photoluminescence quantum yields and narrow-band emission coupled with low cost and relatively facile syntheses. Most recently, critical modifications of the surface capping ligands of these nanocrystals has led to rapid and significant advances regarding the properties of these materials. This team research aims to leverage the modularity of the surface groups on perovskite nanocrystals to form an interface with custom-built biologically active coordination compounds. The resulting hybrid materials will be used as multimodal sensors for challenging biological targets. The primary modality involves photoelectrochemical response where the input (visible light excitation) and output (electrochemical response) signals are decoupled giving rise to a significant limit of detection. Conventional photoluminescence will be explored as a complementary modality, where mechanisms such as energy transfer between the surface coordination compound (with or without target binding) will offer an alternative pathway of detection. The lessons learned through this work are expected to advance the fundamental understanding of energy migration processes at the interface of semiconductor nanocrystals informing the future design of these systems as biosensors, but also as platform materials for energy conversion and catalysis.