A novel fluorescence-electrochemiluminescence dual-mode sensing platform for high-precision BRAF gene detection.

In this study, we innovatively synthesized bipyridine ruthenium cluster nanosheets (RuMOFNCs), a novel metal-organic framework material that exhibits both fluorescence and electrochemiluminescence. Gold nanoparticles (AuNPs) were anchored onto RuMOFNCs via bipyridine chelation, enhancing optical signals and creating sites for attaching biologically functional probes. We employed tetraferrocene-modified DNA probes, linked via gold-sulfur (Au-S) bonds, to construct a dual-mode fluorescence-electrochemiluminescence biosensor. This sensor, exploiting exonuclease III (Exo III)-mediated cyclic amplification, inhibits the electron transfer from RuMOFNC to tetraferrocene, resulting in amplified fluorescence and electrochemiluminescence signals. The sensor demonstrates exceptional sensitivity for detecting the BRAF gene, with fluorescence and electrochemiluminescence detection limits of 10.3 aM (range: 0.1 fM to 1 nM) and 3.1 aM (range: 1 aM to 10 pM), respectively. These capabilities are attributed to RuMOFNCs' luminescence properties, tetraferrocene's quenching effect, and the specificity of base pairing. This study's findings hold substantial promise for biomedical research and clinical diagnostics, particularly in precision medicine and early disease detection.

A novel fluorescent sensor with an overtone peak reference for highly sensitive detection of mercury (II) ions and hydrogen sulfide: Mechanisms and applications in environmental monitoring and bioanalysis.

The present study introduces a novel fluorescent sensor with an overtone peak reference designed for the detection of mercury (Ⅱ) ions (Hg2+) and hydrogen sulfide (H2S). The study proposes two novel response mechanisms that hinges on the synergistic effect of cation exchange dissociation (CED) and photo-induced electron transfer (PET). This sensor exhibits a remarkable detection limit of 2.9 nM for Hg2+. Additionally, the sensor reacts with H2S to generate nickel sulfide (NiS) semiconductor nanoparticles, which amplify the fluorescence signal and enable a detection limit of 3.1 nM for H2S. The detection limit for H2S is further improved to 29.1 pM through the surface functionalization of the nanomaterial with pyridine groups (increasing reactivity) and chelation of gold nanoparticles (AuNPs), which enhances the sensor's specificity. This improvement is primarily due to the surface plasmon resonance (SPR) of AuNPs and their affinity for H2S. The single-emission strategy can yield skewed results due to environmental changes, whereas the overtone peak reference strategy enhances result accuracy and reliability by detecting environmental interference through reference emission peaks. In another observation, the low-toxicity dihydropyrene-bipyridine nanorods (TPP-BPY) has been successfully utilized for both endogenous and exogenous H2S detection in vivo using a mouse model. The successful development of TPP-BPY is expected to provide an effective tool for studying the role of H2S in biomedical systems.

A fluorescence-electrochemiluminescence dual-mode sensor based on a "switch" system for highly selective and sensitive K-ras gene detection.

Herein, an fluorescence (FL)-electrochemiluminescence (ECL) dual-mode biosensor is constructed based on the dual-signal "turn-on" strategy of functionalized metal-organic frameworks nanosheets (RuMOFNSs)-tetraferrocene for K-ras gene detection, and the mechanism of bursting through front-line orbital theory is explained for the first time. Amino-functionalized tetraferrocene-labeled probe DNA molecules are linked to RuMOFNSs by covalent amide bonds, acting as FL and ECL intensity switches. The target DNA, complementary to the probe DNA, triggers cyclic amplification of the target by nucleic acid exonuclease III (Exo III), repelling tetraferrocene reporter groups away from RuMOFNSs and inhibiting the electron transfer process and photoinduced electron transfer (PET) effect. These phenomena induce a double turn-on of FL and ECL signals with a high signal-to-noise ratio. The developed FL-ECL dual-mode sensing platform provides sensitive detection of the K-ras gene with detection limits of 0.01 fM (the detection range is 1 fM to 1 nM) and 0.003 fM (the detection range is 0.01 fM to 10 pM), respectively. In addition, the proposed dual-mode sensor can be easily extended to detect other disease-related biomarkers by changing the specific target and probe base sequences, depicting potential applications in bioanalysis and early disease diagnosis.

An autonomous driven DNA walker-based electrochemical aptasensor for on-site detection of Ochratoxin A.

Herein, an autonomous driven DNA walker-based aptasensor is proposed for the detection of Ochratoxin A (OTA). A nanoscale metal-organic framework (MOF) is synthesized and used to load Mn2+, a cofactor for DNAzyme. The DNA walker and Mn2+@MOF are assembled on the Au surface, integrating the DNA walker and metal auxiliary ions. The proposed sensor avoids the addition of metal auxiliary ions of DNAzyme from the external environment, which achieves the fully autonomous driving of DNA walker and facilitates the on-site detection of OTA. In addition, the substrate strands are modified with a newly synthesized tetraferrocene signal marker, further achieving signal amplification. The sensor demonstrates a sensitivity of 0.289 pg/mL and is successfully applied to real food sample analysis.