Department of Physical and Analytical Chemistry, Faculty of Experimental Sciences, University of Jaén, Campus de las Lagunillas, E-23071 Jaén, Spain.
LAQV, REQUIMTE, Laboratory of Applied Chemistry, Department of Chemical Sciences, Faculty of Pharmacy of Porto University, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
Spectrochim Acta A Mol Biomol Spectrosc. 2019 Apr 5;212:246-254. doi: 10.1016/j.saa.2019.01.005. Epub 2019 Jan 4.
This work focused the implementation of FRET processes between CdTe quantum dots (QDs), acting as donors, and gold nanoparticles (AuNPs), behaving as acceptors, for the determination of several bioactive thiols such as captopril, glutathione, l-cysteine, thiomalic acid and coenzyme M. The surface chemistry of the QDs and AuNPs was adjusted with adequate capping ligands, i.e. mercaptopropionic acid and cysteamine, respectively, to guarantee the establishment of strong electrostatic interaction between them and promoting the formation of stable FRET assemblies. Under these circumstances the fluorescence emission of the QDs was completely suppressed by the AuNPs. The assayed target analytes were capable of disrupting the donor-acceptor assemblies yielding a concentration-related reversion of the FRET process and restoring QDs fluorescence emission. Distinct mechanisms, involving enhancing of the QDs quantum yield (QY), AuNPs agglomeration, nanoparticles detachment, etc., could be proposed to explain the referred FRET reversion. The developed approach assured good analytical working ranges and demonstrate adequate sensitivity for the assayed compounds, anticipating great prospective for implementing rapid, simple and reliable sensing methodologies for the monitoring of pharmaceutical, food and environmental species. However, selectivity could be a hindrance in the detection of these bioactive thiols in more complex matrices such as environmental and food samples. This problem could be circumvented through the employment of multivariate chemometric methods for the analysis and processing of whole fluorometric response. Moreover, the proposed methodology shows a great analytical versatility since it is possible to easily adapt the surface chemistry, of both QDs and AuNPs, to the chemical nature of the target analyte.
本工作重点研究了 CdTe 量子点（QDs）作为供体与金纳米粒子（AuNPs）作为受体之间的 FRET 过程的实现，用于测定几种生物活性硫醇，如卡托普利、谷胱甘肽、l-半胱氨酸、硫代苹果酸和辅酶 M。通过适当的封端配体，即巯基丙酸和半胱氨酸，分别调整了 QDs 和 AuNPs 的表面化学性质，以保证它们之间建立强静电相互作用，并促进稳定的 FRET 组装体的形成。在这种情况下，AuNPs 完全抑制了 QDs 的荧光发射。所测定的目标分析物能够破坏供体-受体组装体，导致 FRET 过程的浓度相关反转，并恢复 QDs 的荧光发射。可以提出不同的机制来解释这种 FRET 反转，包括增强 QDs 的量子产率（QY）、AuNPs 的聚集、纳米粒子的脱离等。所开发的方法保证了良好的分析工作范围，并为所测定的化合物提供了足够的灵敏度，为监测药物、食品和环境物种的快速、简单和可靠的传感方法提供了广阔的前景。然而，选择性可能是在更复杂的基质（如环境和食品样品）中检测这些生物活性硫醇的一个障碍。这个问题可以通过使用多元化学计量方法来分析和处理整个荧光响应来解决。此外，所提出的方法具有很大的分析通用性，因为可以很容易地根据目标分析物的化学性质来调整 QDs 和 AuNPs 的表面化学性质。
