A high-sensitive sensor with HEPES-enhanced electrochemiluminescence of benzo[3]uril for Fe3+ and its application in human serum

A resonance energy transfer electrochemiluminescence sensor based on the synergistic effect of luminol@β-cyclodextrin and Ni-MOF@Pt NPs for the oxytetracycline detection

The electrochemiluminescence (ECL) sensor for detecting oxytetracycline (OTC) was constructed by sequentially modifying luminol@β-cyclodextrin (β-CD) and Ni-MOF@Pt NPs on the electrode surface. In this platform, luminol serves as a luminescent reagent, and Pt NPs serve as co-reaction accelerators of the system. β-CD and Ni-MOF are used as carriers to carry luminol and Pt NPs respectively, and the luminescence intensity was further improved by increasing the carrying capacit. In addition, the OTC quenching strategy is adopted, and the constructed sensor is based on the energy transfer of luminol. Under optimal conditions, this sensor exhibited the linear detection range of OTC was found to be between 2.0 × 10-12 M to 2.0 × 10-7 M, with a detection limit of 6.7 × 10-13 M (S/N = 3). The sensor showed good high selectivity and ultra-sensitivity, and obtained satisfactory results when detecting honey and milk samples.

Photoluminescent and Electrochemiluminescent Detection of Fe3+ Using Cyclometalated Iridium Complexes via Fe3+-Catalyzed Hydrolysis

Ferric ion (Fe3+) is a biologically abundant and important metal ion. We developed several cyclometalated iridium complex-based molecular sensors (1, ppy-1, 1-phen, 1 a, and 1_OMe) for the detection of Fe3+ using an acetal moiety as the reaction site. The acetal moiety in iridium complexes undergoes Fe3+-catalyzed hydrolysis and subsequent formation of a formyl group, resulting in turn-off photoluminescent and electrochemiluminescent responses. Sensor 1 showed excellent selectivity toward Fe3+ over other biologically important metal ions. Furthermore, we compared the performance of the sensors based on the structural differences of the iridium complexes, and revealed a relationship between the structure and chemical properties through electrochemical experiments and computational calculations.

An ultrasensitive solid-state electrochemiluminescence sensor based on Ni-MOF@Ru(bpy)32+ and Au NPs@TiO2 for determination of permethrin

The novel TiO2 and Ni-MOF materials were synthesized and utilized for the detection of permethrin (PET). A highly sensitive solid-state electrochemiluminescence (ECL) sensor was developed based on Ni-MOF@Ru(bpy)32+ and Au NPs@TiO2. In this sensing platform, Ru(bpy)32+-Tripropyl Amine (TPrA) was used as a luminescent signal, Ni-MOF acted as a carrier to carry more luminescent reagents Ru(bpy)32+. Au NPs acted as promoters facilitated electron transport and TiO2 could further enhance the luminescence intensity of the system by synergistical interaction with Au NPs. The possible mechanisms of signal amplification were investigated. The ECL intensity decreased significantly with increasing PET concentration, enabling the determination of PET amount through the observation of the change in ECL signal intensity (ΔI). Under optimal experimental conditions, the linear range of PET concentration from 1.0 × 10-11 mol L-1 to 1.0 × 10-6 mol L-1, with a detection limit of 3.3 × 10-12 mol L-1 (3S/N). This method was successfully applied to determine PET in various vegetable samples.

Ag+-doped boron quantum dots with enhanced stability and fluorescence enabling versatile practicality in visual detection, sensing, imaging and photocatalytic degradation

In this work, a metal-doping strategy was put forward to construct metal-doped borophene and the corresponding zero-dimensional boron. Through theoretical calculations, Ag⁺ acts as the optimal metal ions to prepare Ag⁺-doped borophene derived boron quantum dots (Ag-BQDs). As predicted theoretically, doping of Ag⁺ endows borophene with enhanced stability of electronic structures. The newly emerging Ag-BQDs were experimentally acquired from ultrasonic-assisted liquid-phase exfoliation of bulk boron and solvothermal treatments. According to theoretical and experimental studies, the improved stability and fluorescence (FL) of Ag-BQDs are due to the formation of strong B-Ag bonding to competitively suppress B-O bonding. The function enables the maximal protection of borophene electronic structures from oxidization, destruction and reconfiguration. Because of Ag-BQDs with relatively higher colloidal and FL stability over BQDs, potential applications of Ag-BQDs were further explored in promising fields toward FL visualization in aqueous solutions and on filter paper, employed as a chemosensor of Fe³⁺ for FL sensing and visual detection at the solid/liquid phases, utilized for multiple FL bio-imaging at the levels of fresh plants, live animals and live cells of fresh plants, and applied to photocatalytic degradation of organic dyes and anticancer drug. Experimental results demonstrate excellent performances of Ag-BQDs in multiple applications, including versatile FL sensing and visual detection, unique multi-channel FL bio-imaging and visible-light-driven photodegradation of organic pollutants, toxic and harmful substances. This work can promote the development of metal-ion-doped low- dimensional nanomaterials with improved stability and FL properties for significant applications.

A potential-resolved electrochemiluminescence resonance energy transfer strategy for the simultaneous detection of neuron-specific enolase and the cytokeratin 19 fragment

An electrochemiluminescence resonance energy transfer (ECL-RET) immunosensor was developed based on the potential-resolved technology for the simultaneous detection of neuron-specific enolase (NSE) and the cytokeratin 19 fragment (CYFRA21-1). The absorption spectrum of gold nanorods (AuNRs) perfectly overlapped with the ECL spectra of SnS2@Pt and Ru(bpy)32+/Zn-MOF, so they exhibited an excellent ECL-RET effect with high efficiency. Zn-MOF possesses a large surface area, which allows for the loading of Ru(bpy)32+. This results in a signal probe of Ru(bpy)32+/Zn-MOF/Ab1 showing a strong ECL emission. Simultaneously, owing to the excellent electronic conductivity of PtNPs, they can increase the electron transfer rate between S2O82- and tin disulfide nanoflowers (SnS2NFs). Hence, the ECL signal of SnS2NFs can be enhanced. Under the optimal conditions, the linear range for NSE is 0.2 pg mL-1-20 ng mL-1 with a detection limit of 79 fg mL-1. The linear range for CYFRA21-1 is 1.25 pg mL-1-12.5 ng mL-1 with a detection limit of 0.43 pg mL-1. The proposed immunosensor can be used for the sensitive simultaneous detection of NSE and CYFRA21-1 in human serum and has promise for clinical diagnostics.