Department of Electronic Engineering, Gachon University, 1342 Seongnam-Daero, Seongnam, Gyeonggi-Do 13120, Republic of Korea.
Department of Chemical and Biological Engineering, Gachon University, 1342 Seongnam-Daero, Seongnam, Gyeonggi-Do 13120, Republic of Korea.
Spectrochim Acta A Mol Biomol Spectrosc. 2022 Dec 5;282:121685. doi: 10.1016/j.saa.2022.121685. Epub 2022 Jul 26.
The fluorometric turn-off-on biosensor was developed for the ultra-sensitive detection of mercury (Hg) and cysteine (Cys) utilizing the highly fluorescent carbon dots (CDs). Herein, the sophisticated low-temperature reflux-mediated reaction was adopted using precursors namely citric acid (CA) and polyphenolic kaempferol (KMP) by using dimethylformamide (DMF) as a solvent. The resulting CDs (i.e., CKCDs) were in the highly negative charged groups (-OH) presented with a bright-orange fluorescence. These CKCDs were functionalized with 4-vinylaniline (4-VA) by employing EDC/NHS coupling reaction, which switched its photoluminescence (PL) towards the strong-blue colored emission and termed as V-CKCDs. The functionalized V-CKCDs can be capable enough to detect mercury via the strong electrostatic interactions between positively charged Hg cations and negatively charged anions (-OH groups). Hence, an adequate fluorescence quenching was observed in V-CKCDs with the lowest concentrations of Hg around 0.5 μM. Significantly, after adding the complex of V-CKCDs-Hg to the Cys, the fluorescence enhancement was observed. This might be attributed from the strong interactions between Hg in the fluorescence sensing system and thiol (-SH) moieties from the Cys. The developed V-CKCDs are highly sensitive for detecting Hg and Cys, which showed detection limits of 10.6 and 42. 48 nM, respectively. Also, the in vivo studies were investigated in zebrafish larvae using V-CKCDs for the detection of Hg and Cys. The V-CKCDs were investigated in the real water samples and human serum to detect Hg and Cys, respectively.
荧光猝灭-荧光开启生物传感器是利用高荧光碳点（CDs）为汞（Hg）和半胱氨酸（Cys）的超灵敏检测而开发的。在此，采用了复杂的低温回流介导反应，使用前体柠檬酸（CA）和多酚山柰酚（KMP），以二甲基甲酰胺（DMF）为溶剂。所得的 CDs（即 CKCDs）带有高度带负电荷的基团（-OH），呈现出亮橙色荧光。这些 CKCDs 与 4-乙烯基苯胺（4-VA）通过 EDC/NHS 偶联反应进行功能化，使其光致发光（PL）转向强蓝色发射，并称为 V-CKCDs。功能化的 V-CKCDs 能够通过带正电荷的 Hg 阳离子和带负电荷的阴离子（-OH 基团）之间的强静电相互作用来检测汞。因此，在 V-CKCDs 中观察到最低浓度约为 0.5 μM 的 Hg 时，会出现足够的荧光猝灭。重要的是，在将 V-CKCDs-Hg 复合物添加到 Cys 后，观察到荧光增强。这可能归因于荧光传感系统中的 Hg 与 Cys 中的巯基（-SH）部分之间的强相互作用。所开发的 V-CKCDs 对 Hg 和 Cys 的检测非常敏感，检测限分别为 10.6 和 42.48 nM。此外，还使用 V-CKCDs 在斑马鱼幼虫中进行了体内研究，以检测 Hg 和 Cys。V-CKCDs 用于检测实际水样和人血清中的 Hg 和 Cys。
