An electrochemiluminescence ratiometric self-calibrated biosensor for carcinoembryonic antigen detection

Potential-resolved ratiometric electrochemiluminescence detection for prostate-specific antigen based on CdS nanocrystals modified on carbon nanotubes and luminol functionalized nanocomposites

A ratiometric electrochemiluminescence (ECL) aptamer-based sensing platform was fabricated for prostate-specific antigen (PSA) determination. Activated CdS nanocrystals/multi-walled carbon nanotubes (CdS/MCNTs) and luminol-Pt/PAMAM nanocomposites (L-Pt/PAMAM NCs) were synthesized and used as cathodic and anodic ECL emitters, respectively. Amino group-modified aptamers were assembled on carboxylated magnetic beads, followed by hybridization with probe DNA functionalized L-Pt/PAMAM NCs. In the presence of PSA, the aptamer would bind specifically to the target PSA, thereby releasing L-Pt/PAMAM NCs. After magnetic separation, the separated L-Pt/PAMAM NCs would hybridize with capture DNA on CdS/MCNTs coated on glassy carbon electrode. This binding would lead to a decrease in cathodic ECL signal of CdS/MCNTs, due to the efficient energy transfer from CdS/MCNTs to L-Pt/PAMAM NCs. Meanwhile, L-Pt/PAMAM brought the anodic ECL signal from luminol. With the increase of PSA concentration, the ECL emission from luminol increased and the ECL emission from CdS/MCNTs decreased. The ratio of ECL intensity of luminol at 0.55 V and CdS/MCNTs at - 1.25 V could be used to quantify the concentration of PSA. This method enables sensitive and reliable detection of PSA over a wide range from 0.05 to 200 ng mL-1, and the detection limit is 0.02 ng mL-1.

Dual-binding domain electrochemiluminescence biosensing platform with self-checking function for sensitive detection of synthetic cathinone in e-cigarettes

Current single signal electrochemiluminescence (ECL) sensors are susceptible to false positive or false negative phenomena due to experimental conditions. Therefore, sensors with "self-checking" function are attracting democratic attention. In quick succession, a highly sensitive single-cathode dual ECL signal aptasensor with self-checking function to improve the shortcomings mentioned above was designed. This aptasensor used In-based metal-organic framework (MIL-68) as load and stabilizer to effectively attenuate the aggregation-induced quenching (ACQ) effect of porphyrin derivatives (Sn-TCPP) while improve ECL stability. The introduction of cooperative-binding split-aptamers" (CBSAs) aptamers increased the specificity of the aptasensor and its unique double-binding domains detection accelerated the detection efficiency. When analyzing 3,4-methylenedioxypyrovalerone (MDPV), we could calculate two concentrations based on the strength of ECL 1 and ECL 2. If the concentrations are the same, the result would be obtained; if not, it should be retested. Depending on the above operation, the results achieve self-check. It was found that the designed aptasensor could quantify the concentration of MDPV between 1.0 × 10^-12 g/L and 1.0 × 10^-6 g/L with the limit of detection (LOD) of 1.4 × 10^-13 g/L and 2.0 × 10^-13 g/L, respectively (3 σ/slope). This study not only improves the detection technology of MDPV, but also explores the dual-signal detection of porphyrin for the first time and enriches the definition of self-checking sensor.

Geochronology, Whole-Rock Geochemistry, and Sr–Nd–Hf Isotopes of Granitoids in the Tongshanling Ore Field, South China: Insights into Cu and W Metallogenic Specificity

The Qin-Hang Metallogenic Belt (QHMB), an important metallogenic belt in South China, hosts Cu and W–Sn polymetallic deposits. The Tongshanling ore field in the QHMB is characterized by the coexistence of Cu- and W-bearing polymetallic deposits, which are related to granodiorite and granite porphyry. This study examined whole-rock geochemistry, geochronology, and Sr–Nd–Hf isotopes to determine the genetic relationship between diverse ore-related granitoids (i.e., granodiorite and granite porphyry) and Cu–W metallogeny in the Tongshanling ore field. Zircon LA-ICP-MS U–Pb dating shows that the granodiorite and granite porphyry in the Tongshanling ore field were emplaced at 163.7 ± 0.4 Ma to 154.7 ± 0.6 Ma and 161.1 ± 0.3 Ma, respectively. Geochemically, the granodiorites are classified as oxidized I-type, while the highly evolved granite porphyry is reduced A-type. The Lu–Hf isotopic composition of the granodiorites is characterized by εHf(t) values ranging from –10.49 to –4.99 (average = –7.17), with corresponding TDMC ages ranging from 1524 to 1877 Ma (average = 1682 Ma). In contrast, the granite porphyry has higher εHf(t) values (–3.60 to –1.58, average = –2.78) and younger TDMC (1310–1438 Ma, average = 1387 Ma). The εNd(t) values of granodiorite are −8.06 to −7.37 and the two-stage model ages (TDM2) are 1543–1598 Ma, while the granite porphyry has higher εNd(t) values (−3.0 to −3.4) and younger TDM2 ages (1195–1223 Ma). The results show that the granodiorite and granite porphyry were formed from partial melting of different Mesoproterozoic basement rocks under varying degrees of crust–mantle interaction. Granite porphyry underwent well-recorded fractional crystallization. Compared to the Cu-forming granodiorite, the W-forming granite porphyry has a higher differentiation index, higher crystallization temperatures of zircon (average = 708 °C versus 631 °C), and lower oxygen fugacity (median ΔFMQ = –2.21 versus –1.77).

A spatially resolved ratiometric electrochemiluminescence immunosensor for myoglobin detection using Au@Ag2S as signal amplification tags

A spatially resolved ratiometric ECL immunosensor for myoglobin detection was developed via resonance energy transfer for signal amplification.

A ratiometric electrochemiluminescence sensing platform for robust ascorbic acid analysis based on a molecularly imprinted polymer modified bipolar electrode

Herein, a novel molecularly imprinted polymer (MIP) modified spatial-resolved "on-off" ratiometric electrochemiluminescence (ECL) sensing platform based on a closed bipolar electrode (BPE) has been reported for highly accurate and selective detection of ascorbic acid (AA). AA-imprinted MIP was decorated on the anode of the BPE, and Ru (bpy)₃²⁺ in the anode electrolyte served as anode-emitter, while ZnIn₂S₄ as the other ECL emitter was coated on the cathode. Rebinding of AA at anode promoted ECL response of ZnIn₂S₄ (440 nm) at cathode. Meanwhile, the ECL response at 605 nm decreased, arising from the hindered reaction of Ru (bpy)₃²⁺ on the anode surface. Therefore, an "on-off" BPE-ECL sensing platform was fabricated and showed distinguished performance in repeatability and selectivity thanks to the ratio correction effect and the specific recognition from MIP. The linear range for AA detection is from 50 nM to 3 μM with a low detection limit of 20 nM (S/N = 3). The assay deviation of the ratio responses largely declined by about 15 and 5 times compared with the ones from single pole in the aspect of repeatability and long-term stability, respectively. This work provides a reliable and stable sensing pattern for practical application, which also furnishes a strategy for designing simple and low-cost ECL sensing devices.