In this paper, logic gates with electrochemiluminescence (ECL) signal as outputs were constructed based on the use of the thymine (T)-rich (S1) or cytosine (C)-rich (S2) oligonucleotides for the selective analysis of mercury ions (Hg2+) or silver ions (Ag+), respectively. Firstly, Ru-silica (Ru(bpy)32+-doped silica) labeled S1 and S2 were absorbed onto multiwalled carbon nanotubes (MCNTs) to form MCNTs/Ru-silica labeled S1/Ru-silica labeled S2 complex, which result in the quenching of the ECL of Ru-silica via the energy-transfer and electron-transfer process. Upon the MCNTs/S1/S2 interaction and coordination chemistry of Hg2+ bridge thymine bases and Ag+ specifically bridge cytosine bases, OR, INHIBIT, and NOR logic gates were designed to operate the ECL of Ru-silica nanoparticles. The ECL signal changed according to different input combinations, and the combinatorial logic gates (OR and INHIBIT) provided a beneficial approach for multiplex analysis. The proposed logic gates may have a great potential in further DNA circuits and advanced sensors for the identification of multiple targets in complex chemical environments.

A novel water-soluble polyfluorene derivative, poly[(9,9-bis(3′-((N,N-dimethylamino)N-ethylammonium)propyl)-2,7-fluorene)-alt-2,7-(9,9-p-divinylbenzene)]dibromide (P-2) was synthesized by the palladium-catalyzed Suzuki coupling reaction and it’s quaternized ammonium polyelectrolyte derivatives was obtained through a postpolymerization treatment on the terminal amino groups. The electrochemical and optical properties of the copolymers was fully investigated. The results showed that the new polyfluorene derivative had high electronic conductivity and strong fluorescence, therefore it had good potential to be used in chemical and biological sensors, as shown in optical sensing of bovine albumin (BSA) in this study.Graphical abstractA novel water-soluble polyfluorene derivative (P-2) was synthesized. P-2 showed good fluorescence performance which is beneficial to the application of P-2 for fluorescence sensor, we established a novel fluorescence probe-P-2 as a probe to determine BSA. The method has high sensitivity and simplicity of operation.Highlights► A novel water-soluble polyfluorene derivative (P-2) was synthesized. ► P-2 is more suitable for biosensory systems in aqueous solution. ► Strong fluorescence enhanced sensitivity to oppositely charged quenchers BSA. ► Simplicity of operation, a novel luminescence probe.

A novel chemiluminescence sensor for determination deltamethrin was firstly reported based on CdTe quantum dots and deltamethrin imprinted polymers by layer-by-layer assembly modified on the surface of slide glass, whose shape was the same as the bottom of 96 well micro-plate. The binding characteristic of the imprinted polymers to deltamethrin was evaluated by equilibrium binding experiments and the morphology was studied by scanning electronic microscope. Scatchard analysis was carried out to estimate the binding parameters of the imprinted polymers. The water-soluble TGA-capped CdTe quantum dots were prepared. NaHTe was used as the Te precursor for CdTe quantum dots synthesis. Under the optimum conditions, the chemiluminescence intensity had a linear relationship against the concentration of deltamethrin over the range of 0.053–46.5 μg mL−1 with a lower detection limit of 0.018 μg mL−1. The regression equation was ΔI = 2225 + 107c (c: μg mL−1) with a correlation coefficient of 0.9973. The relative standard deviation was 4.7%. The presented method was applied successfully to the determination of deltamethrin in real samples with satisfactory results.

A novel fluorescent nanosensor for Sb3+ determination was reported based on thioglycolic acid (TGA)-capped CdTe quantum dot (QD) nanoparticles. It was the first antimony ion sensor using QD nanoparticles in a receptor-fluorophore system. The water-soluable TGA-capped CdTe QDs were prepared through a hydrothermal route, NaHTe was used as the Te precursor for CdTe QDs synthesis. Bovine serum albumin (BSA) conjugated to TGA-capped CdTe via an amide link interacting with carboxyl of the TGA-capped CdTe. When antimony ion enters the BSA, the lone pair electrons of the nitrogen and oxygen atom become involved in the coordination, switching off the QD emission and a dramatic quenching of the fluorescence intensity results, allowing the detection of low concentrations of antimony ions. Using the operating principle, the antimony ion sensor based on QD nanoparticles showed a very good linearity in the range 0.10–22.0 μg L−1, with the detection limit lower than 2.94 × 10−8 g L−1 and the relative standard deviation (RSD) 2.54% (n = 6). In a study of interferences, the antimony-sensitive TGA-QD-BSA sensor showed good selectivity. Therefore, a simple, fast, sensitive, and highly selective assay for antimony has been built. The presented method has been applied successfully to the determination of antimony in real water samples (n = 6) with satisfactory results.