A Tröger's base-linked aluminium phthalocyanine polymer for discriminative electrochemical sensing of the antibiotic isoniazid.

Isoniazid is a first-line drug used to treat tuberculosis. However, its excessive use can lead to serious adverse effects. Thus, strict monitoring of the isoniazid levels in medications and human systems is required. In this study, a new polymer (AlPc-TB POP) containing a metal phthalocyanine and Tröger's base was synthesized and explored as an electrocatalyst for the oxidation of isoniazid. The results indicated that the polymer is an excellent electron-transfer medium for isoniazid oxidation. The AlPc-TB POP-based sensor quantified isoniazid in the linear range of 0.1-130 µM, with a detection limit of 0.0185 µM. The response of the developed sensor to isoniazid was reproducible and stable. Furthermore, this method can accurately determine isoniazid levels by ignoring the influence of common interfering species in tablets and biological samples. This study contributes to the development of nitrogen-rich porous organic polymers and offers a novel strategy for addressing challenges in disease therapeutic efficacy and public safety monitoring.

Conductive phthalocyanine-based porous organic polymer as sensing platform for rapid determination of vanillin.

Vanillin (Van) is widely utilized in processed foods and medicines for its appealing scent and multiple therapeutic benefits. However, its overconsumption poses a risk to public health, making its quantification essential for ensuring food and medicine safety and quality. This study introduces a stable and conductive phthalocyanine-based porous organic polymer (NiPc-CC POP), synthesized through a straightforward electrophilic substitution of nickel tetra-amine phthalocyanine (NiTAPc) with cyanuric chloride (CC). Appropriate characterization techniques were employed to determine the morphologies and structures of the synthesized materials. Furthermore, the NiPc-CC POP was applied to devise a sensitive Van detection method. Leveraging the high electrocatalytic activity of NiPc-CC POP toward Van oxidation, a linear response of 0.15-32 µmol L-1 was achieved, along with an exceptional detection limit of 0.10 µmol L-1. The sensor demonstrated high selectivity and stability. Samples of human serum and tablets spiked with Van were analyzed, yielding satisfactory recoveries. Consequently, this work contributes to the advancement of sensitive detection platforms for Van at minimal concentrations.

3D C-Co-N-anchored MWCNTs derived from metal-organic frameworks as high-performance electrochemical sensing platforms for the sensitive detection of adrenaline.

Metal-organic frameworks (MOFs) are composed of metal ions and organic ligands with high specific surface areas, controllable porous structures and abundant metal active sites, showing their extraordinary potential in electrochemical sensors. Here, a 3D conductive network structure (C-Co-N@MWCNTs) is designed by anchoring zeolite imidazole frameworks (ZIF-67) onto multi-walled carbon nanotubes (MWCNTs) and carbonizing them. The C-Co-N@MWCNTs exhibit excellent electron conductivity, a porous structure and considerable electrochemical active sites, which can effectively demonstrate high sensitivity and selectivity in the detection of adrenaline (Ad). The Ad sensor exhibited a low detection limit of 6.7 nmol L-1 (S/N = 3) and a wide linear range of 0.02 µmol L-1-1.0 mmol L-1. The developed sensor also displayed high selectivity, good reproducibility and repeatability. The C-Co-N@MWCNTs electrode was further employed in the detection of Ad in a real sample of human serum, suggesting that it is a promising candidate for electrochemical sensing of Ad.

A Sensitive Photoelectrochemical Sensor for Levodopa Detection Using Benzothiadiazole-Based Conjugated Microporous Polymer-Coated Graphene Heterostructures.

Since the 1960s, levodopa (LDA) has been the standard drug for treating of Parkinson's disease. In this study, a novel benzothiadiazole-based conjugated microporous polymer-coated graphene heterostructure (CMP-rGO) was synthesized and used to construct a sensitive photoelectrochemical (PEC) sensor capable of detecting LDA. Under optimal experimental conditions, the intensity of the photocurrent produced by the sensor was linear from 0.005 to 40 µM, and the limit of detection of the sensor was 0.0027 µM. The sensor showed good repeatability, stability, and selectivity for LDA detection. Finally, the constructed sensor was used to detect LDA in levodopa tablets, human serum samples, and urine samples and satisfactory results were obtained. Therefore, the PEC sensor provides a novel platform for the detection of LDA in real samples and broadens the applications of conjugated microporous polymers in PEC sensing.

Photoelectrochemical detection for 3,3',4,4'-tetrachlorobiphenyl in fish based on synergistic effects by Schottky junction and sensitization.

In this study, a novel signal amplification strategy on photoelectrochemical (PEC) aptasensor was designed for high-sensitivity and -selectivity detection of 3,3',4,4'-tetrachlorobiphenyl (PCB77) on the basis of Schottky junction and sensitization. First, the Schottky barrier not only provided an electron-transfer irreversible passage from CuO to Au Nanoparticles (NPs) but also generated excellent local surface plasmon resonance between CuO and Au NPs, thus improving the efficiency of charge separation and light absorption. Second, to further improve the response of the PEC aptasensor under the action of the sensitization, the complementary-DNA-functionalized CdS quantum dots were introduced onto the surface of CuO/Au NPs via hybridization of the target aptamer. The PEC aptasensor exhibited a low detection limit of 17.3 pg L-1, and a wide linear response was shown at a range of 0.2-220 ng L-1 depending on the variation of photocurrent before and after incubation.

Integration of Multiple Redox Centers into Porous Coordination Networks for Ratiometric Sensing of Dissolved Oxygen.

The application of porphyrin metal-organic frameworks (MOFs) as a ratiometric electrochemical sensing platform is still unexplored. In this paper, we report a ratiometric electrochemical sensor by the integration of multiple redox centers into porphyrin MOFs for the detection of dissolved oxygen (DO). Specifically, the ferrocene (Fc) group was integrated into the nanosized PCN-222(Fe) (PCN = porous coordination networks) via acid-base reaction to synthesize the Fc@PCN-222(Fe) composite with two redox centers of the Fc group and Fe-porphyrin. The Fc group that is insensitive to DO serves as an internal reference, and the Fe-porphyrin in PCN-222(Fe) is a DO indicator. The ratios of the cathodic currents for the two redox centers exhibit a linear relationship with DO concentrations from 2.8 to 28.9 mg mL-1 and a limit of detection of 0.3 mg mL-1. In addition, the ratiometric electrochemical sensor has high selectivity and stability for DO sensing results from the Fc@PCN-222(Fe) composite. Because there are numerous redox centers, such as methylene blue and thionine, which can be integrated into MOFs, many MOF-based ratiometric electrochemical sensors can be simply developed for high-performance biosensing.

Au Quantum Dot/Nickel Tetraminophthalocyanaine-Graphene Oxide-Based Photoelectrochemical Microsensor for Ultrasensitive Epinephrine Detection.

Owing to the importance of epinephrine as a neurotransmitter and hormone, sensitive methods are required for its detection. We have developed a sensitive photoelectrochemical (PEC) microsensor based on gold quantum dots (Au QDs) decorated on a nickel tetraminophthalocyanine-graphene oxide (NiTAPc-Gr) composite. NiTAPc was covalently attached to the surface of graphene oxide to prepare NiTAPc-Gr, which exhibits remarkable stability and PEC performance. In situ growth of Au QDs on the NiTAPc-Gr surface was achieved using chemical reduction at room temperature. The synthesized materials were characterized by Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and electrochemical impedance spectroscopy. Au QDs@NiTAPc-Gr provided a much greater photocurrent than NiTAPc-Gr, making it suitable for the ultrasensitive PEC detection of epinephrine. The proposed PEC strategy exhibited a wide linear range of 0.12-243.9 nM with a low detection limit of 17.9 pM (S/N = 3). Additionally, the fabricated PEC sensor showed excellent sensitivity, remarkable stability, and good selectivity. This simple, fast, and low-cost strategy was successfully applied to the analysis of human serum samples, indicating the potential of this method for clinical detection applications.

Novel porous iron phthalocyanine based metal-organic framework electrochemical sensor for sensitive vanillin detection.

Vanillin is widely used as a flavor enhancer and is known to have numerous other interesting properties, including antidepressant, anticancer, anti-inflammatory, and antioxidant effects. However, as excess vanillin consumption can affect liver and kidney function, simple and rapid detection methods for vanillin are required. Herein, a novel electrochemical sensor for the sensitive determination of vanillin was fabricated using an iron phthalocyanine (FePc)-based metal-organic framework (MOF). Scanning electron microscopy and transmission electron microscopy showed that the FePc MOF has a hollow porous structure and a large surface area, which impart this material with high adsorption performance. A glassy carbon electrode modified with the FePc MOF exhibited good electrocatalytic performance for the detection of vanillin. In particular, this vanillin sensor had a wide linear range of 0.22-29.14 µM with a low detection limit of 0.05 µM (S/N = 3). Moreover, the proposed sensor was successfully applied to the determination of vanillin in real samples such as vanillin tablets and human serum.

Blue-light photoelectrochemical sensor based on nickel tetra-amined phthalocyanine-graphene oxide covalent compound for ultrasensitive detection of erythromycin.

In this study, we developed a novel photoelectrochemical (PEC) sensor for the highly sensitive detection of erythromycin by functionalising graphene oxide (GO) with nickel tetra-amined phthalocyanine (NiTAPc) through covalent bonding, which resulted in the formation of NiTAPc-Gr. The fabricated sensor showed a higher PEC efficiency under blue light, exhibiting a peak wavelength of 456 nm, as compared to that of the monomer. Further, the NiTAPc-Gr/indium tin oxide (ITO) sensor exhibited a photocurrent that was 50-fold higher than that for a GO/ITO sensor under the same conditions. Under optimal conditions, the NiTAPc-Gr PEC sensor showed a linear response for erythromycin concentrations ranging from 0.40 to 120.00 µmol L-1, with the minimum limit for detection being 0.08 µmol L-1. Thus, the NiTAPc-Gr sensor exhibited superior performance and excellent PEC characteristics, high stability, and good reproducibility with respect to the sensing of erythromycin. Moreover, it is convenient to use, fast, small, and cheap to produce. Hence, it should find wide use in the analysis of erythromycin in real-world applications.

(110)-oriented ZIF-8 thin films on ITO with controllable thickness.

(110)-oriented zeolitic imidazolate framework (ZIF)-8 thin films with controllable thickness are successfully deposited on indium tin oxide (ITO) electrodes at room temperature. The method applied uses 3-aminopropyltriethoxysilane (APTES) in the form of self-assembled monolayers (SAMs), followed by a subsequent adoption of the layer-by-layer (LBL) method. The crystallographic preferential orientation (CPO) index shows that the ZIF-8 thin films are (110)-oriented. A possible mechanism for the growth of the (110)-oriented ZIF-8 thin films on 3-aminopropyltriethoxysilane modified ITO is proposed. The observed cross-sectional scanning electron microscopy (SEM) images and photoluminescent (PL) spectra of the ZIF-8 thin films indicate that the thickness of the ZIF-8 layers is proportional to the number of growth cycles. The extension of such a SAM method for the fabrication of ZIF-8 thin films as described herein should be applicable in other ZIF materials, and the as-prepared ZIF-8 thin films on ITO may be explored for photoelectrochemical applications.

Simultaneous determination of ultratrace lead and cadmium by square wave stripping voltammetry with in situ depositing bismuth at Nafion-medical stone doped disposable electrode.

An ultrasensitive electrochemical method for simultaneous determination of lead and cadmium was first developed using the novel bismuth-Nafion-medical stone doped disposable electrode (an improved wax-impregnated graphite electrode). Through the synergistic sensitization effect of the resulting composite material, the disposable electrode showed remarkable electrochemical responses to lead and cadmium. The oxidation of the two metals produced two well-defined and separated square wave peaks at about -0.62 V for Pb(2+) and -0.85 V for Cd(2+), respectively. The effects of the amount of medical stone, concentration of Nafion, thickness of bismuth, pH of buffer solution, deposition potential, accumulation time, voltammetric measurement and possible interferences were investigated in detail. Under the optimal conditions, the fabricated electrode exhibited linear ranges from 2.0 to 12.0 µg L(-1) with detection limit of 0.07 µg L(-1) for lead and 2.0-12.0 µg L(-1) with detection limit of 0.47 µg L(-1) for cadmium. The assay results of heavy metals in wastewater with the proposed method were in acceptable agreement with the atomic absorption spectroscopy method.

The prevalence of Epstein-Barr virus infection in different types and sites of lymphomas.

To analyze the association of several types of malignant lymphomas in different anatomical sites with the Epstein-Barr virus (EBV) infection status, 127 cases of formalin-fixed paraffin-embedded samples of malignant lymphomas were investigated with in situ hybridization detecting EBV-encoded small RNA (EBER) in tumor cells. Forty-six out of 108 non-Hodgkin lymphoma (NHL) cases were positive for EBER (42.6%). The EBER-positivity rate of NHL in the nasal cavity and nasopharynx (35/60 cases, 58.3%) was higher than that of NHL in stomach (9/30 cases, 30%) and in the superficial lymph nodes (2/18 cases, 11.1%) (P<0.05). The EBER-positivity rate of Hodgkin lymphoma in the superficial lymph nodes was 26.3% (5/19 cases). These findings suggest that the EBV-positivity rate in lymphomas is related to their histological types and locations.

Determination of proteins with tetracarboxy manganese(II) phthalocyanine by resonance light scattering technique.

A novel method for the determination of proteins by using tetracarboxy manganese(II) phthalocyanine (MnC4Pc) as a resonance light scattering (RLS) probe has been developed. At pH 3.0 Britton-Robinson (B-R) buffer solution, the RLS intensity of MnC4Pc at 385 nm is greatly enhanced in the presence of proteins. The effects of pH, reaction time, concentration of MnC4Pc and interfering substances on the enhanced RLS intensity are investigated, respectively. Under optimal conditions, the linear ranges of the calibration curves are 0-2.00 microg mL(-1) for bovine serum albumin (BSA) and human serum albumin (HSA), 0.0-1.75 microg mL(-1) for human-IgG and ovalbumin, with a detection limit of 16.37 ng mL(-1) BSA, 17.62 ng mL(-1) HSA, 19.41 ng mL(-1) human-IgG and 20.72 ng mL(-1) ovalbumin. The method has been applied to the determination of total proteins in human serum samples collected from a hospital and the results are in good agreement with those reported by the hospital.