Dual-Ligand Europium-Organic Gels as a Highly Efficient Anodic Annihilation Electrochemiluminescence Emitter for Ultrasensitive Detection of MicroRNA.

In this study, a novel europium dual-ligand metal-organic gel (Eu-D-MOGs) with high-efficient anodic annihilation electrochemiluminescence (ECL) was synthesized as an ECL emitter to construct a biosensor for ultrasensitive detection of microRNA-221 (miR-221). Impressively, compared to the ECL signal of europium single-ligand metal-organic gels (Eu-S-MOGs), the ECL signal of Eu-D-MOGs was significantly improved since the two organic ligands could jointly replace the H2O and coordinate with Eu3+, which could remarkably reduce the nonradiative vibrational energy transfer caused by the coordination between H2O and Eu3+ with a high coordination demand. In addition, Eu-D-MOGs could be electrochemically oxidized to Eu-D-MOGs•+ at 1.45 V and reduced to Eu-D-MOGs•- at 0.65 V to achieve effective annihilation of ECL, which overcame the side reaction brought by the remaining emitters at negative potential. This benefited from the annihilation ECL performance of the central ion Eu3+ caused by its redox in the electrochemical process. Furthermore, the annihilation ECL signal of Eu3+ could be improved by sensitizing Eu3+ via the antenna effect. In addition, combined with the improved rolling circle amplification-assisted strand displacement amplification strategy (RCA-SDA), a sensitive biosensor was constructed for the sensitive detection of miR-221 with a low detection limit of 5.12 aM and could be successfully applied for the detection of miR-221 in the lysate of cancer cells. This strategy offered a unique approach to synthesizing metal-organic gels as ECL emitters without a coreactant for the construction of ECL biosensing platforms in biomarker detection and disease diagnosis.

[Values of (99m)TcO(-)(4)thyroid imaging plus ultrasonography in the differential diagnoses of thyroid nodules].

OBJECTIVE: To evaluate the diagnostic values of (99m)TcO(-)(4) thyroid imaging plus ultrasonography in the differentiation of benign and malignant thyroid nodules. METHODS: (99m)TcO(-)(4) thyroid imaging and ultrasonography were performed for 114 patients with 125 thyroid nodules. And the examination results were compared with the post-operative pathological findings. RESULTS: (1) Among 125 thyroid nodules, there were thyroid adenoma (n = 64, 51.2%), thyroid cancer (n = 30, 24.0%) and other thyroid diseases (n = 31, 24.8%). On thyroid images, 73.6% of them were of cold nodules. And among these cold nodules, 25.0% were of thyroid cancer. Among the ultrasonic results, 125 nodules were predominantly of solid nodules and mixed solid and cystic nodules while the malignant rate of solid nodules was the highest. (2) The malignant rate of solid cool or cold nodules was greater than those of mixed solid and cystic cool or cold nodules (P < 0.005). (3)In solid cool or cold nodules with a diameter of ≥ 2.0 cm, thyroid cancer accounted for 62.5%. CONCLUSION: The combination of (99m)TcO(-)(4) thyroid imaging and ultrasonography may help to evaluate the (99m)TcO(-)(4) uptaking functions of thyroid nodules so that it plays an important role in the differentiation of benign and malignant thyroid nodules.