Jain Shikha, Nehra Monika, Kumar Rajesh, Dilbaghi Neeraj, Kim Ki-Hyun, Kumar Sandeep
Department of Bio and Nano Technology, Guru Jambheshwar University of Science and Technology, Hisar, Haryana, 125001, India.
Department of Mechanical Engineering, University Institute of Engineering and Technology, Panjab University, Chandigarh, 160014, India.
Mikrochim Acta. 2024 May 11;191(6):324. doi: 10.1007/s00604-024-06382-5.
A robust "on-off" fluorescent aptasensor was developed using nanohybrids of molybdenum sulfide (MoS) quantum dot (QD)-doped zinc metal-organic frameworks (Zn-MOF) for selective and sensitive detection of cadmium ions (Cd) in water. This nanohybrid (MoS@Zn-MOF), synthesized via "bottle around the ship" methodology, exhibited a high-intensity fluorescence emission centered at 430 nm (λ) (blue) on excitation at 320 nm (λ). Further, the conjugation of this fluorophore to phosphate-modified cadmium aptamer (Cd-2-2) was achieved through carbodiimide reaction. The hybridization of prepared sensing probe (MoS@Zn-MOF/Cd-2-2 aptamer) was done with dabcyl-conjugated complementary DNA (cDNA), acting as energy donor-acceptor pair in the fluorescence resonance energy transfer (FRET) system. This hybridization causes the fluorescence quenching of the nanohybrid. In the presence of Cd, the aptamer from the fabricated nano-biosensing probe binds to these ions, resulting in release of dabcyl-cDNA oligomer. This release of dabcyl-cDNA oligomer from the sensing probes restores the fluorescence of the nanohybrid. Under optimized conditions (sensing probe/dabcyl-cDNA ratio 1/7, pH 7.4, and temp 28 °C), the sensing probe showed a fast response time of 1 min. The fluorescence intensity of the nanohybrid can be utilized to determine the concentration of Cd. The proposed aptasensor achieved highly sensitive detection of Cd with a limit of detection (LOD) of 0.24 ppb over the range of 1 × 10 to 1 × 10 M along with minimal effects of interferences (e.g., Hg, Pb, and Zn) and good reproducibility. The designed aptasensor based on MoS@Zn-MOF nanofluorophore offers a highly sensitive and selective approach for rapid screening of metal ions in aqueous environments.
利用硫化钼（MoS）量子点（QD）掺杂的锌金属有机框架（Zn-MOF）的纳米杂化物，开发了一种用于选择性和灵敏检测水中镉离子（Cd）的稳健的“开-关”荧光适配体传感器。这种通过“船中瓶”方法合成的纳米杂化物（MoS@Zn-MOF）在320nm（λ）激发下，呈现出以430nm（λ）（蓝色）为中心的高强度荧光发射。此外，通过碳二亚胺反应实现了该荧光团与磷酸化修饰的镉适配体（Cd-2-2）的共轭。制备的传感探针（MoS@Zn-MOF/Cd-2-2适配体）与作为荧光共振能量转移（FRET）系统中能量供体-受体对的达比酰共轭互补DNA（cDNA）进行杂交。这种杂交导致纳米杂化物的荧光猝灭。在存在Cd的情况下，制备的纳米生物传感探针中的适配体与这些离子结合，导致达比酰-cDNA寡聚物释放。传感探针中达比酰-cDNA寡聚物的这种释放恢复了纳米杂化物的荧光。在优化条件下（传感探针/达比酰-cDNA比例1/7、pH 7.4和温度28°C），传感探针显示出1分钟的快速响应时间。纳米杂化物的荧光强度可用于确定Cd的浓度。所提出的适配体传感器实现了对Cd的高灵敏检测，在1×10至1×10 M范围内的检测限（LOD）为0.24 ppb，同时干扰（如Hg、Pb和Zn）的影响最小且重现性良好。基于MoS@Zn-MOF纳米荧光团设计的适配体传感器为快速筛选水环境中的金属离子提供了一种高灵敏且选择性的方法。
