Multifaceted Applications of Luminescent Metalloporphyrin Derivatives: Fluorescence Turn-On Sensing of Nicotine and Antimicrobial Activity.

In this study, we designed and synthesized metalloporphyrin derivatives (with Ni and Zn) specifically intended for the fluorescence detection of nicotine in aqueous solutions. Our results showcased a notable selectivity for nicotine over other naturally occurring food toxins, exhibiting an exceptional sensitivity with a limit of detection as low as 7.2 nM. Through mechanistic investigations (1H NMR, FT-IR, etc.), we elucidated the binding mechanism, revealing the specific interaction between the pyridine ring of nicotine and the metal center, while the N atom pyrrolidine unit engaged in the hydrogen bonding with the side chain of the porphyrin ring. Notably, we observed that the nature of the metal center dictated the extent of interaction with nicotine; particularly, Zn-porphyrin demonstrated a superior response compared to Ni-porphyrin. Furthermore, we performed the quantitative estimation of nicotine in commercially available tobacco products. Additionally, we conducted the antibacterial (Staphylococcus aureus and Escherichia coli) and antifungal (Candida albicans) activities of the porphyrin derivatives.

A novel self-enhanced ECL-RET aptasensor based on the bimetallic MOFs with homogeneous catalytic sites for kanamycin detection.

The inappropriate use of antibiotics undoubtedly poses a potential threat to public health, creating an increasing need to develop highly sensitive tests. In this study, we designed a new type of porphyrin metal-organic frameworks (Fe TCPP(Zn) MOFs) with homogeneous catalytic sites. The ferric-based metal ligands of Fe TCPP(Zn) MOFs acted as co-reaction accelerators, which effectively improved the conversion efficiency of H2O2 on the surface of MOFs, then increased the concentration of •OH surrounding porphyrin molecules to achieve self-enhanced electrochemiluminescence (ECL). Based on this, an aptasensor for the specific detection of kanamycin (KAN) in food and environmental water samples was constructed in combination with resonance energy transform (RET), in which Fe TCPP(Zn) MOFs were used as luminescence donor and AuNPs were used as acceptor. Under the best conditions, there was a good linear relationship between the ECL intensity and the logarithm of KAN concentration with a detection limit of 0.28 fM in the range of 1.0 × 10-7-1.0 × 10-13 M, demonstrating satisfactory selectivity and stability. At the same time, the complexity of the detection environment was reduced, which further realized the reliable analysis of KAN in milk, honey and pond water. Overall, this innovative self-enhanced ECL strategy provides a novel approach for constructing efficient ECL systems in MOFs, and also extends the application of MOFs to the analysis and detection of trace antibiotics in food and the environment.

Fluorination of porphyrin ß-periphery boosts nickel(II)-catalyzed hydrogen evolution reaction.

Tunichlorin, the naturally occurring chlorophyll cofactor containing Ni(II) ion, sets up a golden standard for designing the electrocatalysts for hydrogen evolution reaction (HER) via ß-peripheral modification. Besides the fine-tuning of the porphyrin ß-periphery such as adjusting the aromatics (the saturated level of tetrapyrrole) or installing hydroxyl group (hydrogen bond network) to enhance the catalytic HER efficiency, here we report that ß-fluorination of porphyrin is also an important approach to increase the reactivity of Ni(II) center. Benefiting the previously reported derivatization of ß-fluorinated porpholactones, we constructed a ß-fluorinated tunichlorin mimic (6). Compared with the non-fluorinated analogs (1, 3, and 5), we found that 2, 4, and 6 exhibit significant electrocatalytic HER reactivity acceleration (in terms of turnover frequencies, TOF, s-1) of ca. 37, 170, 133-fold, respectively. Mechanism studies suggested that ß-fluorination negatively shifts the metal complexes' reduction potentials and accelerates the electron transfer process, both contributing to the boosting of HER reaction. Notably, 6 showed an 890-fold increase of TOFs than 1, demonstrating the combining advantages of the of fluorination, hydrogenation, and hydroxylation at porphyrin ß-periphery.

Evaluation of Iron Chlorin e6 disappearance and hydrolysis in soil and garlic using salting-out assisted liquid-liquid extraction coupled with high-performance liquid chromatography and ultraviolet-visible detection.

Iron Chlorin e6 (ICE6), a star plant growth regulator (PGR) with independent intellectual property rights in China, has demonstrated its efficacy through numerous field experiments. We innovatively employed salting-out assisted liquid-liquid extraction (SALLE) with HPLC-UV/Vis to detect ICE6 residues in water, soil, garlic seeds, and sprouts. Using methanol and a C18 column with acetonitrile: 0.1% phosphoric acid mobile phase (55:45, v:v), we achieved a low LOQ of 0.43 to 0.77 µg kg-1. Calibration curves showed strong linearity (R2 > 0.992) within 0.01 to 5.00 mg kg-1. Inter-day and intra-day recoveries (0.05 to 0.50 mg kg-1) demonstrated high sensitivity and accuracy (recoveries: 75.36% to 107.86%; RSD: 1.03% to 8.78%). Additionally, density functional theory (DFT) analysis aligned UV/Vis spectra and indicated ICE6's first-order degradation (2.03 to 4.94 days) under various environmental conditions, mainly driven by abiotic degradation. This study enhances understanding of ICE6's environmental behavior, aids in risk assessment, and guides responsible use in agroecosystems.

Amphiphilic Block Copolymers Containing Benzenesulfonyl Azide Groups as Visible Light-Responsive Drug Carriers for Image-Guided Delivery.

Nanoparticles (NPs) containing light-responsive polymers and imaging agents show great promise for controlled drug delivery. However, most light-responsive NPs rely on short-wavelength excitation, resulting in poor tissue penetration and potential cytotoxicity. Moreover, excessively sensitive NPs may prematurely release drugs during storage and circulation, diminishing their efficacy and causing off-target toxicity. Herein, we report visible-light-responsive NPs composed of an amphiphilic block copolymer containing responsive 4-acrylamide benzenesulfonyl azide (ABSA) and hydrophilic N,N'-dimethylacrylamide (DMA) units. The polymer pDMA-ABSA was loaded with the chemotherapy drug dasatinib and zinc tetraphenylporphyrin (ZnTPP). ZnTPP acted as an imaging reagent and a photosensitizer to reduce ABSA upon visible light irradiation, converting hydrophobic units to hydrophilic units and disrupting NPs to trigger drug release. These NPs enabled real-time fluorescence imaging in cells and exhibited synergistic chemophotodynamic therapy against multiple cancer cell lines. Our light-responsive NP platform holds great promise for controlled drug delivery and cancer theranostics, circumventing the limitations of traditional photosensitive nanosystems.

Lutetium texaphyrin: A photocatalyst that triggers pyroptosis via biomolecular photoredox catalysis.

Photon-controlled pyroptosis activation (PhotoPyro) is a promising technique for cancer immunotherapy due to its noninvasive nature, precise control, and ease of operation. Here, we report that biomolecular photoredox catalysis in cells might be an important mechanism underlying PhotoPyro. Our findings reveal that the photocatalyst lutetium texaphyrin (MLu) facilitates rapid and direct photoredox oxidation of nicotinamide adenine dinucleotide, nicotinamide adenine dinucleotide phosphate, and various amino acids, thereby triggering pyroptosis through the caspase 3/GSDME pathway. This mechanism is distinct from the well-established role of MLu as a photodynamic therapy sensitizer in cells. Two analogs of MLu, bearing different coordinated central metal cations, were also explored as controls. The first control, gadolinium texaphyrin (MGd), is a weak photocatalyst but generates reactive oxygen species (ROS) efficiently. The second control, manganese texaphyrin (MMn), is ineffective as both a photocatalyst and a ROS generator. Neither MGd nor MMn was found to trigger pyroptosis under the conditions where MLu was active. Even in the presence of a ROS scavenger, treating MDA-MB-231 cells with MLu at concentrations as low as 50 nM still allows for pyroptosis photo-activation. The present findings highlight how biomolecular photoredox catalysis could contribute to pyroptosis activation by mechanisms largely independent of ROS.

Zinc porphyrin/MXene hybrids with phosphate-induced stimuli-responsive behavior for dual-mode fluorescent/electrochemiluminescent ratiometric biosensing.

Highly sensitive ratiometric biosensors have attracted much attention in biomarker detection, but most rely on single-mode signals, which can affect accuracy. The development of new principles and methods for dual-mode ratiometric sensing can enhance detection accuracy. Herein, the zinc(II) meso-tetra(4-carboxyphenyl) porphyrin/MXene (ZnTCPP/Ti3C2Tx) hybrids with phosphate-induced stimuli-responsive behavior are used to develop a novel dual-mode fluorescent/electrochemiluminescent (FL/ECL) ratiometric biosensor. The composites exhibit FL quenching and enhanced ECL behavior involving dissolved O2. The FL quenching of ZnTCPP/Ti3C2Tx is caused by energy transfer (EnT) and photo-induced electron transfer (PET) from ZnTCPP to Ti3C2Tx. While the introduction of MXene compensates for the inadequate conductivity of ZnTCPP, facilitating electron transfer, which further makes the surface ZnTCPP more capable of activating O2 to produce singlet oxygen (1O2), thereby generating enhanced cathodic ECL. Furthermore, phosphate ions (PO43-) can interact with the Ti sites of ZnTCPP/Ti3C2Tx, leading to competition for coordination with ZnTCPP, which in turn detaches ZnTCPP, resulting in enhanced FL and reduced ECL. On the basis of the phosphate-induced stimuli-responsive behavior, the dual-mode FL/ECL ratiometric biosensing of alkaline phosphatase (ALP) is achieved through ALP-catalyzed production of PO43- cascade effect with ZnTCPP/Ti3C2Tx. The linear detection range for ALP is 0.1-50 mU/mL, with a detection limit as low as 0.0083 mU/mL. This proposed ZnTCPP/Ti3C2Tx composites with stimuli-responsive behavior is expected to provide new ideas for the development of high-sensitivity dual-mode ratiometric biosensors with promising applications in the precise detection of important biomarkers.

Distinct concentration-dependent oxidative stress profiles by cadmium in a rat kidney proximal tubule cell line.

Levels and chemical species of reactive oxygen/nitrogen species (ROS/RNS) determine oxidative eustress and distress. Abundance of uptake pathways and high oxygen consumption for ATP-dependent transport makes the renal proximal tubule particularly susceptible to cadmium (Cd2+)-induced oxidative stress by targeting ROS/RNS generation or antioxidant defence mechanisms, such as superoxide dismutase (SOD) or H2O2-metabolizing catalase (CAT). Though ROS/RNS are well-evidenced, the role of distinct ROS profiles in Cd2+ concentration-dependent toxicity is not clear. In renal cells, Cd2+ (10-50 µM) oxidized dihydrorhodamine 123, reaching a maximum at 2-3 h. Increases (up to fourfold) in lipid peroxidation by TBARS assay and H2O2 by Amplex Red were evident within 30 min. ROS and loss in cell viability by MTT assay with 50 µM Cd2+ could not be fully reversed by SOD mimetics Tempol and MnTBAP nor by SOD1 overexpression, whereas CAT expression and α-tocopherol were effective. SOD and CAT activities were attenuated below controls only with >6 h 50 µM Cd2+, yet augmented by up to 1.5- and 1.2-fold, respectively, by 10 µM Cd2+. Moreover, 10 µM, but not 25-50 µM Cd2+, caused 1.7-fold increase in superoxide anion (O2•-), detected by dihydroethidium, paralled by loss in cell viability, that was abolished by Tempol, MnTBAP, α-tocopherol and SOD1 or CAT overexpression. H2O2-generating NADPH oxidase 4 (NOX4) was attenuated by ~50% with 10 µM Cd2+ at 3 h compared to upregulation by 50 µM Cd2+ (~1.4-fold, 30 min), which was sustained for 24 h. In summary, O2•- predominates with low-moderate Cd2+, driving an adaptive response, whereas oxidative stress by elevated H2O2 at high Cd2+ triggers cell death signaling pathways.Highlights Different levels of reactive oxygen species are generated, depending on cadmium concentration. Superoxide anion predominates and H2O2 is suppressed with low cadmium representing oxidative eustress. High cadmium fosters H2O2 by inhibiting catalase and increasing NOX4 leading to oxidative distress. Superoxide dismutase mimetics and overexpression were less effective with high versus low cadmium. Oxidative stress profile could dictate downstream signalling pathways.

Design and Synthesis of Metalloporphyrin Nanoconjugates for Dual Light-Responsive Antimicrobial Photodynamic Therapy.

Antimicrobial photodynamic therapy (APDT) utilizes photosensitizers (PSs) that eradicate a broad spectrum of bacteria in the presence of light and molecular oxygen. On the other hand, some light sources such as ultraviolet (UVB and UVC) have poor penetration and high cytotoxicity, leading to undesired PDT of the PSs. Herein, we have synthesized conjugatable mesosubstituted porphyrins and extensively characterized them. Time-dependent density functional theory (TD-DFT) calculations revealed that metalloporphyrin EP (5) is a suitable candidate for further applications. Subsequently, the metalloporphyrin was conjugated with lignin-based zinc oxide nanocomposites (ZnOAL and ZnOKL) to develop hydrophilic nanoconjugates (ZnOAL@EP and ZnOKL@EP). Upon dual light (UV + green light) exposure, nanoconjugates showed enhanced singlet oxygen generation ability and also demonstrated pH responsiveness. These nanoconjugates displayed significantly improved APDT efficiency (4-7 fold increase) to treat bacterial infection under dual light irradiation.

Renewable-based treatment solution of Reactive Blue 21 dye on fly ash as low-cost and sustainable adsorbent.

This study investigated the removal of Reactive Blue 21 (RB 21) dye from aqueous solutions by adsorption, evaluating the waste fly ash (FA). The effects of the parameters, such as initial dye concentration (100-750 mg/L), initial pH (2.0-8.0), adsorbent dose (1.0-4.0 g/L), and temperature (298-323 K) on the adsorption process were investigated. The optimum initial pH value was 2.0 for the highest RB21 dye removal (75.2 mg/g). At optimized conditions (pH 2.0, an adsorbent dosage of 1.0 g/L, a dye concentration of 750 mg/L, and an equilibrium time of 72 h), the highest adsorption capacity was found to be 105.2 mg/g. Moreover, the results of the kinetic studies fitted the pseudo-second-order kinetic model. Equilibrium data were best represented by the Langmuir isotherm model, with a maximum monolayer adsorption capacity of 103.41 mg/g at 323 K. ΔGads0 values were negative and varied from 11.64 to 9.50 kJ/mol in the temperature range of 298-323 K, the values of enthalpy (ΔHadso) and entropy (ΔSadso) of thermodynamics parameters were calculated as 37.62 kJ/mol and 86.67 J/mol K, respectively, indicating that this process was endothermic. Furthermore, the adsorbent costs for powdered activated carbon (PAC) and FA to remove 1 kg of RB 21 dye from aqueous solutions are calculated as 2.52 U.S. $ and 0.34 U.S. $, respectively. It is seen that the cost of FA is approximately 7.4 times lower than PAC. The results showed that FA, a low-cost industrial waste, was promising for the adsorption of RB 21 from aqueous solutions.

Novel Catalytic Antioxidant Formulation Decreases Oxidative Stress, Neuroinflammation and Cognitive Dysfunction in a Model of Nerve Agent Intoxication.

Reactive oxygen species have an emerging role in the pathologic consequences of status epilepticus. We have previously demonstrated the efficacy of a water-for-injection formulation of the meso-porphyrin catalytic antioxidant, manganese (III) meso-tetrakis (N-N-diethylimidazole) porphyrin (AEOL10150) against oxidative stress, neuroinflammation, and neuronal death initiated by kainic acid, pilocarpine, diisopropylflurophosphate (DFP), and soman. This previous dose and dosing strategy of AEOL10150 required smaller multiple daily injections, precluding our ability to test its efficacy against delayed consequences of nerve agent exposure such as neurodegeneration and cognitive dysfunction. Therefore, we developed formulations of AEOL10150 designed to deliver a larger dose once daily with improved brain pharmacodynamics. We examined four new formulations of AEOL10150 that resulted in 8 times higher subcutaneous dose with lower acute toxicity, slower absorption, longer half-life, and higher maximal plasma concentrations compared with our previous strategy. AEOL10150 brain levels exhibited improved pharmacodynamics over 24 hours with all four formulations. We tested a subcutaneous dose of 40 mg/kg AEOL10150 in two formulations (2% carboxymethyl cellulose and 4% polyethylene glycol-4000) in the DFP rat model, and both formulations exhibited significant protection against DFP-induced oxidative stress. Additionally, and in one formulation (4% polyethylene glycol-4000), AEOL10150 significantly protected against DFP-induced neuronal death, microglial activation, delayed memory impairment, and mortality. These results suggest that reformulation of AEOL10150 can attenuate acute and delayed outcomes of organophosphate neurotoxicity. SIGNIFICANCE STATEMENT: Reformulation of manganese (III) meso-tetrakis (N-N-diethylimidazole) porphyrin allowed higher tolerated doses of the compound with improved pharmacodynamics. Specifically, one new formulation allowed fewer daily doses and improvement in acute and delayed outcomes of organophosphate toxicity.

Dissecting components of the Campylobacter jejuni fetMP-fetABCDEF gene cluster under iron limitation.

IMPORTANCE: Campylobacter jejuni is a bacterium that is prevalent in the ceca of farmed poultry such as chickens. Consumption of ill-prepared poultry is thus the most common route by which C. jejuni infects the human gut to cause a typically self-limiting but severe gastrointestinal illness that can be fatal to very young, old, or immunocompromised people. The lack of a vaccine and an increasing resistance to current antibiotics highlight a need to better understand the mechanisms that make C. jejuni a successful human pathogen. This study focused on the functional components of one such mechanism-a molecular system that helps C. jejuni thrive despite the restriction on growth-available iron by the human body, which typically defends against pathogens. In providing a deeper understanding of how this system functions, this study contributes toward the goal of reducing the enormous global socioeconomic burden caused by C. jejuni.

The heme oxygenase-1 metalloporphyrin inhibitor stannsoporfin enhances the bactericidal activity of a novel regimen for multidrug-resistant tuberculosis in a murine model.

Multidrug-resistant (MDR) Mycobacterium tuberculosis (Mtb) poses significant challenges to global tuberculosis (TB) control efforts. Host-directed therapies (HDTs) offer a novel approach to TB treatment by enhancing immune-mediated clearance of Mtb. Prior preclinical studies found that the inhibition of heme oxygenase-1 (HO-1), an enzyme involved in heme metabolism, with tin-protoporphyrin IX (SnPP) significantly reduced mouse lung bacillary burden when co-administered with the first-line antitubercular regimen. Here, we evaluated the adjunctive HDT activity of a novel HO-1 inhibitor, stannsoporfin (SnMP), in combination with a novel MDR-TB regimen comprising a next-generation diarylquinoline, TBAJ-876 (S), pretomanid (Pa), and a new oxazolidinone, TBI-223 (O) (collectively, SPaO), in Mtb-infected BALB/c mice. After 4 weeks of treatment, SPaO + SnMP 5mg/kg reduced mean lung bacillary burden by an additional 0.69 log10 (P = 0.01) relative to SPaO alone. As early as 2 weeks post-treatment initiation, SnMP adjunctive therapy differentially altered the expression of pro-inflammatory cytokine genes and CD38, a marker of M1 macrophages. Next, we evaluated the sterilizing potential of SnMP adjunctive therapy in a mouse model of microbiological relapse. After 6 weeks of treatment, SPaO + SnMP 10mg/kg reduced lung bacterial burdens to 0.71 ± 0.23 log10 colony-forming units (CFUs), a 0.78 log-fold greater decrease in lung CFU compared to SpaO alone (P = 0.005). However, adjunctive SnMP did not reduce microbiological relapse rates after 5 or 6 weeks of treatment. SnMP was well tolerated and did not significantly alter gross or histological lung pathology. SnMP is a promising HDT candidate requiring further study in combination with regimens for drug-resistant TB.

Effect of the nature of the chelated metal on the photodynamic activity of metalloporphyrins.

Coordination of metal ions by the tetrapyrrolic macrocyclic ring of porphyrin-based photosensitizers (PSs) affects their photophysical properties and consequently, their photodynamic activity. Diamagnetic metals increase the singlet oxygen quantum yield while paramagnetic metals have the opposite effect. Since singlet oxygen is considered the main cell-damaging species in photodynamic therapy (PDT), the nature of the chelated cation would directly affect PDT efficacy. This expectation, however, is not always supported by experimental results and numerous exceptions have been reported. Understanding the effect of the chelated metal is hindered because different chelators were used. The aim of this work was to investigate the effect of the nature of chelated cation on the photophysical and photodynamic properties of metalloporphyrins, using the same tetrapyrrole core as a chelator of Ag(II), Cu(II), Fe(III), In(III), Mn(III), or Zn(II). Results demonstrated that with the exception of Ag(II), all paramagnetic metalloporphyrins were inefficient as generators of singlet oxygen and did not act as PSs. In contrast, the coordination of diamagnetic ions produced highly efficient PSs. The unexpected photodynamic activity of the Ag(II)-containing porphyrin was attributed to reduction of the chelated Ag(II) to Ag(I) or to demetallation of the complex, caused by cellular reductants and/or by exposure to light. Our results indicate that in biological systems, where PSs localize to various organelles and are subjected to the action of enzymes, reactive metabolites, and reducing or oxidizing agents, their physicochemical and photosensitizing properties change. Consequently, the photophysical properties alone cannot predict the anticancer efficacy of a PS.

Metalloporphyrin-Based Metal-Organic Frameworks for the Ultrasensitive Chemiresistive Detection of NO2: Effect of the Central Metal on Tuning the Sensing Performance.

The highly sensitive and selective detection of trace hazardous gases at room temperature is very promising for health protection and environmental safety. Herein, chemiresistive sensors for NO2 were fabricated based on self-assembled films of the four metalloporphyrin (MPor)-based metal-organic frameworks PCN-222-M (M = Cu, Ni, Co, Fe) by the quasi-Langmuir-Shäfer method. It is found that the relative responses of the four PCN-222-M films are linearly related to the NO2 concentration, and the PCN-222-Cu possessed an unprecedented high response to NO2 with a sensitivity of 2209% ppm-1 in the 4-20 ppb range and a low limit of detection (LOD) of 0.93 ppb, achieving the best performance reported so far for NO2 detection at room temperature. Meanwhile, PCN-222-Ni showed the fastest recovery among the four PCN-222-M films, which can be used for the rapid detection of NO2. Excellent reproducibility, stability, selectivity, and moisture resistance are shown for both PCN-222-Cu and PCN-222-Ni. Combining the experimental study and density functional theory (DFT) calculation, the essential roles of MPor units and the MPor/Zr6 cluster hybrid material in tuning the Fermi level and the electron transfer between PCN-222-M and NO2 were further proved. These were less considered topics in previous studies on MOFs. This work explores the application of MPor-based MOFs in gas sensing by selecting appropriate MPor units, thus providing guidance for the development of MOF-based chemiresistive sensors.

Metal Modulation: An Effortless Tactic for Refining Photoredox Catalysis in Living Cells.

The remarkable impact of photoredox catalytic chemistries has sparked a wave of innovation, opening doors to novel biotechnologies in the realm of catalytic antitumor therapy. Yet, the quest for novel photoredox catalysts (PCs) suitable for living systems, or the enhancement of catalytic efficacy in existing biocompatible PC systems, persists as a formidable challenge. Within this context, we introduce a readily applicable metal modulation strategy that significantly augments photoredox catalysis within living cells, exemplified by a set of metalloporphyrin complexes termed M-TCPPs (M = Zn, Mn, Ni, Co, Cu). Among these complexes, Zn-TCPP emerges as an exceptional catalyst, displaying remarkable photocatalytic activity in the oxidation of nicotinamide adenine dinucleotide (NADH), nicotinamide adenine dinucleotide phosphate (NADPH), and specific amino acids. Notably, comprehensive investigations reveal that Zn-TCPP's superior catalytic prowess primarily arises from the establishment of an efficient oxidative cycle for PC, in contrast to previously reported PCs engaged in reductive cycles. Moreover, theoretical calculations illuminate that amplified intersystem crossing rates and geometry alterations in Zn-TCPP contribute to its heightened photocatalytic performance. In vitro studies demonstrated that Zn-TCPP exhibits therapeutic potential and is found to be effective for photocatalytic antitumor therapy in both glioblastoma G98T cells and 3D multicellular spheroids. This study underscores the transformative role of "metal modulation" in advancing high-performance PCs for catalytic antitumor therapy, marking a significant stride toward the realization of this innovative therapeutic approach.

SERS Tracking Oxidative Stress on a Metalloporphyrin Framework by Vitamin C.

Accurate control of charge transfer is crucial to investigate the catalytic reaction mechanism of the biological oxidation process that biomedicine participates in. Herein, we have established an assembly model of metalloporphyrin framework (MPF) nanosheets as the active centers of biological enzymes. The introduction of Vitamin C (VC) into the MPF system can precisely modulate its content of charges. The surface-enhanced Raman scattering activity and peroxidase-like catalytic performance are enhanced simultaneously for the first time by manipulating the optimal molar ratio of an MPF to VC and the reaction sequence with target model molecules. We have confirmed that the formation of the intermediate of Fe(2+)-OOH species is specifically enhanced after VC modulation, which indicates that VC can regulate the oxidative stress of the active center of biological enzymes. This discovery not only accurately resolves the mechanism of VC-selective anticancer therapy but also has important significance for the precise treatment of VC synergistic targeting medicines.

Trajectory in biological metal-organic frameworks: Biosensing and sustainable strategies-perspectives and challenges.

The ligand attribute of biomolecules to form coordination bonds with metal ions led to the discovery of a novel class of materials called biomolecule-associated metal-organic frameworks (Bio-MOFs). These biomolecules coordinate in multiple ways and provide versatile applications. Far-spread bio-ligands include nucleobases, amino acids, peptides, cyclodextrins, saccharides, porphyrins/metalloporphyrin, proteins, etc. Low-toxicity, self-assembly, stability, designable and selectable porous size, the existence of rigid and flexible forms, bio-compatibility, and synergistic interactions between metal ions have led Bio-MOFs to be commercialized in industries such as sensors, food, pharma, and eco-sensing. The rapid growth and commercialization are stunted by absolute bio-compatibility issues, bulk morphology that makes it rigid to alter shape/porosity, longer reaction times, and inadequate research. This review elucidates the structural vitality, biocompatibility issues, and vital sensing applications, including challenges for incorporating bio-ligands into MOF. Critical innovations in Bio-MOFs' applicative spectrum, including sustainable food packaging, biosensing, insulin and phosphoprotein detection, gas sensing, CO2 capture, pesticide carriers, toxicant adsorptions, etc., have been elucidated. Emphasis is placed on biosensing and biomedical applications with biomimetic catalysis and sensitive sensor designing.

Superlow Power Consumption Memristor Based on Borphyrin-Deoxyribonucleic Acid Composite Films as Artificial Synapse for Neuromorphic Computing.

Memristor synapses based on green and pollution-free organic materials are expected to facilitate biorealistic neuromorphic computing and to be an important step toward the next generation of green electronics. Metalloporphyrin is an organic compound that widely exists in nature with good biocompatibility and stable chemical properties, and has already been used to fabricate memristors. However, the application of metalloporphyrin-based memristors as synaptic devices still faces challenges, such as realizing a high switching ratio, low power consumption, and bidirectional conductance modulation. We developed a memristor that improves the resistive switching (RS) characteristics of Zn(II)meso-tetra(4-carboxyphenyl) porphine (ZnTCPP) by combining it with deoxyribonucleic acid (DNA) in a composite film. The as-fabricated ZnTCPP-DNA-based device showed excellent RS memory characteristics with a sufficiently high switching ratio of up to ∼104, super low power consumption of ∼39.56 nW, good cycling stability, and data retention capability. Moreover, bidirectional conductance modulation of the ZnTCPP-DNA-based device can be controlled by modulating the amplitudes, durations, and intervals of positive and negative pulses. The ZnTCPP-DNA-based device was used to successfully simulate a series of synaptic functions including long-term potentiation, long-term depression, spike time-dependent plasticity, paired-pulse facilitation, excitatory postsynaptic current, and human learning behavior, which demonstrates its potential applicability to neuromorphic devices. A two-layer artificial neural network was used to demonstrate the digit recognition ability of the ZnTCPP-DNA-based device, which reached 97.22% after 100 training iterations. These results create a new avenue for the research and development of green electronics and have major implications for green low-power neuromorphic computing in the future.

Computational screening of metalloporphyrin-based drug carriers for antitumor drug 5-fluorouracil.

Developing novel nanoscale carriers for drug delivery is of great significance for improving treatment efficiency and reducing side effects of antitumor drugs. In view of the good biocompatibility and special affinity of porphyrin (PP) molecule to cancer cells, it was used to construct a series of metal-doped M@PP (M = Ca âˆ¼ Zn) materials for the delivery of anticancer drug 5-fluorouracil (5-Fu) in this work. Our results reveal that 5-Fu is tightly adsorbed on M@PP (M = Ca âˆ¼ V, Mn âˆ¼ Co, and Zn) by chemisorption, but is physically adsorbed by M@PP (M = Cr, Ni, and Cu). The calculated electronic properties show that all these 5-Fu@[M@PP] (M = Ca âˆ¼ Zn) complexes have both high stability and solubility. Among these 5-Fu@[M@PP] complexes, the chemical bond formed between 5-Fu and Ti@PP has the strongest covalent characteristic, resulting in the largest adsorption energy of -19.93 kcal/mol for 5-Fu@[Ti@PP]. In particular, 5-Fu@[Ti@PP] has the proper recovery time under the near-infrared light at body temperature, which further suggests that Ti@PP is the best drug carrier for 5-Fu. This study not only reveals the interaction strength and nature between 5-Fu and M@PP, but also confirmed the intriguing potential of Ti@PP as nano-carrier for drug delivery. However, further experimental research should be conducted to verify the conclusion obtained in this work.