Search Results (24)

Obesity is a chronic epidemic caused by abnormal fat metabolism. As a key digestive enzyme, pancreatic lipase (PL) is an important target for regulating fat metabolism. The inhibitory potential of 5,10,15,20-Tetrakis (4-aminophenyl) porphyrin (TAPP), 5,10,15,20-Tetrakis (4-hydroxyphenyl) porphyrin (THPP), meso-Tetra (4-carboxyphenyl) porphine (TCPP), Cu (II) meso-Tetra (4-carboxyphenyl) porphine (Cu-TCPP) on PL was studied by enzymatic kinetics, multi-spectral, and molecular simulation technology. THPP, TCPP, TAPP, and Cu-TCPP all had good PL inhibitory activity (IC₅₀ range: 97.49–248.70 μM) and were uncompetitive inhibitors. The order of inhibitory ability was: THPP > TCPP > TAPP > Cu-TCPP. The fluorescence quenching mechanism of THPP to PL was a mixed quenching dominated by static quenching, while TCPP, TAPP, and Cu-TCPP were static quenching. The binding of THPP, TCPP and TAPP to PL was mainly driven by hydrogen bonds and van der Waals forces, while Cu-TCPP was mainly driven by a hydrophobic interaction. Four porphyrin compounds changed the conformation of PL, affected the microenvironment of Tyr and Trp residues, and induced changes in the secondary structure of PL, thereby reducing the stability and catalytic activity of PL. Hydrogen bonds played an important role in the binding stability of THPP, TCPP, TAPP, and PL. Full article

Heterocyclic aromatic amines (HAAs), known for their mutagenic and carcinogenic potential, are formed during the heating of protein-rich food items. Detecting HAAs swiftly and accurately poses challenges due to complex food matrices and low HAA concentrations. In this study, a simple and efficient magnetic solid-phase extraction (MSPE) strategy was developed for the simultaneous isolation and enrichment of three HAAs such as 2-amino-3,4,8-trimethylimidazo [4,5-f]quinoxaline (4,8-DiMeIQx), 2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline (MeIQx), and 2-amino-3-methylimidazo [4,5-f]quinoline (IQ) in processed meats, employing the magnetic covalent organic framework Fe₃O₄@MOF-545-AMSA as an adsorbent. It was synthesized via a solvothermal method, with Fe₃O₄ as the magnetic core. Its building blocks are as follows: zirconium (Zr) as the coordination metal ion, tetrakis(4-carboxyphenyl)porphyrin and benzoic acid as organic ligands, and aminomethanesulfonic acid (AMSA). This composite captures targeted HAAs efficiently by exploiting the unique porous MOF-545-AMSA structure, specific metal–ligand coordination, and AMSA’s amino and sulfonic acid groups. The quantification of HAAs was achieved through the combination of Ultra-Performance Liquid Chromatography–Tandem Mass Spectrometry (UPLC-MS/MS) and MSPE, demonstrating satisfactory linearity (R² ≥ 0.9917), high recovery rates (83.7–111.0%), and low detection limits (0.1–1.0 μg/kg). Moreover, an automated high-throughput detection system was developed using MSPE to assess the presence of HAAs in meat products. Full article

Two porphyrin-based polymeric frameworks, SnP-BTC and SnP-BTB, as visible light photocatalysts for wastewater remediation were prepared by the solvothermal reaction of trans-dihydroxo-[5,15,10,20-tetrakis(phenyl)porphyrinato]tin(IV) (SnP) with 1,3,5-benzenetricarboxylic acid (H₃BTC) and 1,3,5-tris(4-carboxyphenyl)benzene (H₃BTB), respectively. The strong bond between the carboxylic acid group of H₃BTC and H₃BTB with the axial hydroxyl moiety of SnP leads to the formation of highly stable polymeric architectures. Incorporating the carboxylic acid group onto the surface of SnP changes the conformational frameworks as well as produces rigid structural transformation that includes permanent porosity, good thermodynamic stability, interesting morphology, and excellent photocatalytic degradation activity against AM dye and TC antibiotic under visible light irradiation. The photocatalytic degradation activities of AM dye were found to be 95% by SnP-BTB and 87% by SnP-BTC within 80 min. Within 60 min of visible light exposure, the photocatalytic degradation activities of TC antibiotic were found to be 70% by SnP-BTB and 60% by SnP-BTC. The enhanced catalytic photodegradation performances of SnP-BTB and SnP-BTC were attributed to the synergistic effect between SnP and carboxylic acid groups. The carboxylic acid connectors strongly resist the separation of SnP from the surface of SnP-BTB and SnP-BTC during the photodegradation experiments. Therefore, the high degradation rate and low catalyst loading make SnP-BTB or SnP-BTC more efficient than other reported catalysts. Thus, the present investigations on the porphyrin-based photocatalysts hold great promise in tackling the treatment of dyeing wastewater. Full article

In this study, 3,4-diaminobenzoic acid (DABA) was introduced into the porphyrin metal–organic framework (PCN-224) for the first time to prepare a ratiometric fluorescent probe (PCN-224-DABA) to quantitatively detect ferric iron (Fe(III)) and selenium (IV) (Se(IV)). The fluorescence attributed to the DABA of PCN-224-DABA at 345 nm can be selectively quenched by Fe(III) and Se(IV), but the fluorescence emission peak attributed to tetrakis (4-carboxyphenyl) porphyrin (TCPP) at 475 nm will not be disturbed. Therefore, the ratio of I_345nm/I_475nm with an excitation wavelength of 270 nm can be designed to determine Fe(III) and Se(IV). After the experimental parameters were systematically optimized, the developed method shows good selectivity and interference resistance for Fe(III) and Se(IV) detection, and has good linearity in the ranges of 0.01–4 μM and 0.01–15 μM for Fe(III) and Se(IV) with a limit of detection of 0.045 μM and 0.804 μM, respectively. Furthermore, the quenching pattern was investigated through the Stern–Volmer equation, and the results suggest that both Se(IV) and Fe(III) quenched on PCN-224-DABA can be attributed to the dynamic quenching. Finally, the constructed ratiometric fluorescent probe was applied in the spiked detection of lake water samples, which shows good applicability in real sample analysis. Moreover, the Fe(III) and Se(IV) contents in spinach and selenium-enriched rice were determined, respectively. Full article

Efforts have been made to improve the therapeutic efficiency of tumor treatments, and metal-organic frameworks (MOFs) have shown excellent potential in tumor therapy. Monotherapy for the treatment of tumors has limited effects due to the limitation of response conditions and inevitable multidrug resistance, which seriously affect the clinical therapeutic effect. In this study, we chose to construct a multiple cascade synergistic tumor drug delivery system MIL−101(Fe)−DOX−TCPP−MnO₂@PDA−Ag (MDTM@P−Ag) using MOFs as drug carriers. Under near-infrared (NIR) laser irradiation, 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) and Ag NPs loaded on MDTM@P−Ag can be activated to generate cytotoxic reactive oxygen species (ROS) and achieve photothermal conversion, thus effectively inducing the apoptosis of tumor cells and achieving a combined photodynamic/photothermal therapy. Once released at the tumor site, manganese dioxide (MnO₂) can catalyze the decomposition of hydrogen peroxide (H₂O₂) in the acidic microenvironment of the tumor to generate oxygen (O₂) and alleviate the hypoxic environment of the tumor. Fe³⁺/Mn²⁺ will mediate a Fenton/Fenton-like reaction to generate cytotoxic hydroxyl radicals (·OH), while depleting the high concentration of glutathione (GSH) in the tumor, thus enhancing the chemodynamic therapeutic effect. The successful preparation of the tumor drug delivery system and its good synergistic chemodynamic/photodynamic/photothermal therapeutic effect in tumor treatment can be demonstrated by the experimental results of material characterization, performance testing and in vitro experiments. Full article

An electrochemical method was developed to investigate the redox properties of zinc oxide (ZnO), zinc peroxide (ZnO₂), and sodium-doped zinc peroxide (Na-ZnO₂) nanoparticles. The intention was to distinguish the identity of these nanoparticles among themselves, and from other transition metal oxide nanoparticles (TMONPs). Analysis of 3 mM sodium metabisulfite by cyclic voltammetry (CV) produced anodic/cathodic peak currents that are linearly related to the mass of deposited nanoparticles. A graphite working electrode was essential to the oxidation of metabisulfite. ZnO nanoparticles were crucial to the enhancement of metabisulfite oxidation current, and PPy coating could suppress the current enhancement by covering all nanoparticle surfaces. Furthermore, meso-tetrakis(4-carboxyphenyl) porphyrin was demonstrated to be a good chemical reagent that facilitates the differentiation of ZnO from ZnO₂ and nanoparticles by CV analysis. Full article

Metal–organic frameworks (MOFs) are highly nanostructured coordination polymers that contain metal cations and organic linkers and feature very large pore volumes and surface areas. The sorption and desorption of n-pentane vapor by porphyrin aluminum metal–organic framework Al-MOF-TCPPH₂ where TCPPH₂ is tetrakis(4-carboxyphenyl)porphyrin linker were studied by a novel method of in-situ time-dependent attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy in a controlled atmosphere and complementary in-situ and ex-situ methods. Sorption facilely occurs in the flow of dried air, and in the obtained adsorption complex the adsorbate molecules interact with phenyl and carboxylate groups of the linker and the O-H group. Sorption kinetics follows the pseudo-first-order rate law, as confirmed by in-situ time-dependent gravimetry. Further, an ex-situ (static) sorption of n-pentane vapor results in an adsorption complex with as much as 29.1 wt.% n-pentane with the stoichiometric formula [Al-MOF-TCPPH₂]₂(n-C₅H₁₂)₇ and a distinct XRD pattern. Finally, in the flow of dried air, the adsorption complex gradually desorbed n-pentane, following the pseudo-first-order rate law. The reversibility of sorption and desorption makes porphyrin aluminum MOF promising for the separation of light hydrocarbons and chemo-sensing. In-situ time-dependent ATR-FTIR spectroscopy in a controlled atmosphere, in combination with in-situ time-dependent gravimetry, is a new approach for the determination of binding sites of sorbents with adsorbate molecules, the stoichiometry of complexes, and chemical kinetics of “solid–gas” interactions. Full article

Dopamine (DA) is an important neurotransmitter. Abnormal concentration of DA can result in many neurological diseases. Developing reliable determination methods for DA is of great significance for the diagnosis and monitoring of neurological diseases. Here, a novel and simple electrochemical sensing platform for quantitative analysis of DA was constructed based on the Cu-TCPP/graphene composite (TCPP: Tetrakis(4-carboxyphenyl)porphyrin). Cu-TCPP frameworks were selected in consideration of their good electrochemical sensing potential. The graphene nanosheets with excellent conductivity were then added to further improve the sensing efficiency and stability of Cu-TCPP frameworks. The electrochemical properties of the Cu-TCPP/graphene composite were characterized, showing its large electrode active area, fast electron transfer, and good sensing performance toward DA. The signal enhancement mechanism of DA was explored. Strong accumulation ability and high electrocatalytic rate were observed on the surface of Cu-TCPP/graphene-modified glassy carbon electrode (Cu-TCPP/graphene/GCE). Based on the synergistic sensitization effect, an ultrasensitive and simple DA electrochemical sensor was developed. The linear range is 0.02–100 and 100–1000 µM, and the detection limit is 3.6 nM for the first linear range. It was also successfully used in detecting DA in serum samples, and a satisfactory recovery was obtained. Full article

In this work, a g-C₃N₄/porphyrin nanocomposite was fabricated through the self-assembling of monomeric Tetrakis (4-carboxyphenyl) porphyrin (TCPP) molecules with g-C₃N₄ nanomaterials. The characterizing results showed a good distribution of TCPP nanofibers with a diameter of < 100 nm and several micrometers in length on the g-C₃N₄ nanoflakes’ surfaces. The prepared g-C₃N₄/porphyrin nanocomposite had two bandgap energies of 2.38 and 2.7 eV, which could harvest a wide range of photon energy in the light spectrum, particularly in visible light. The obtained C₃N₄/TCPP nanocomposite revealed a remarkable photodegradation efficiency toward rhodamine B dyes, with a RhB removing rate of 3.3 × 10⁻² min⁻¹. The plausible mechanism for the photocatalytic performance of the g-C₃N₄/porphyrin photocatalyst for the RhB dye’s degradation was also studied and discussed. Full article

An efficient strategy to develop porous materials with potential for NO₂ sensing was based in the preparation of a metal-organic framework (MOF), UiO-66(Hf), modified with a very small amount of meso-tetrakis(4-carboxyphenyl) N-methylpyrrolidine-fused chlorin (TCPC), TCPC@MOF. Chlorin’s incorporation into the UiO-66(Hf) framework was verified by several characterization methods and revealed that the as-synthesized TCPC@MOF brings together the chemical stability of UiO-66(Hf) and the photophysical properties of the pyrrolidine-fused chlorin which is about five times more emissive than the porphyrin counterpart. TCPC@MOF was further incorporated into polydimethylsiloxane (PDMS) and the resulting TCPC@MOF@PDMS film was tested in NO₂ gas sensing. It showed notable sensitivity as well as a fast response in the range between 0.5 and 500 ppm where an emission intensity quenching is observed up to 96% for 500 ppm. This is a rare example of a chlorin-derivative used for gas-sensing applications through emission changes, and an unusual case of this type of optical-sensing composites of NO₂. Full article

Highly sensitive and specific detection of biomolecular markers is of great importance to the diagnosis and treatment of related diseases. Herein, Cu-TCPP@MOFs thin films were synthesized with tetrakis(4-carboxyphenyl) porphyrin (H₂TCPP) as organic ligands and copper ions as metal nodes. The as-synthesized Cu-TCPP@MOFs thin films as electrode modifiers were used to modify the pre-treated glassy carbon electrode (GCE) and the electrochemical performances of Cu-TCPP@MOFs/GCE were evaluated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Furthermore, as the working electrode, the constructed Cu-TCPP@MOFs/GCE was used for the investigation of ascorbic acid (AA) due to its outstanding electrocatalytic activities towards AA by several electrochemical methods, including cyclic voltammetry (CV), differential pulse voltammetry (DPV), and chronoamperometry (CA). The well-linear relationship was established based on different AA concentration ranges and the ideal detection limits (LOD) were obtained in the above-mentioned electrochemical methods, respectively. Furthermore, a Cu-TCPP MOFs@GCE sensing platform was used as a photoelectrochemical (PEC) sensor to quantitatively detect AA based on the strong absorption properties of Cu-TCPP ingredients in Cu-TCPP MOFs in a visible light band of 400~700 nm. PEC sensing platform based on Cu-TCPP@MOFs exhibited a more extensive linear concentration range, more ideal detection limit, and better sensitivity relative than the other electrochemical methods for AA. The well linear regression equations were established between the peak current intensity and AA concentrations in different electrochemical technologies, including CV, DPV, and CA, and PEC technology. AA concentration ranges applicable to various electrochemical equations were as follows: 0.45~2.10 mM of CV, 0.75~2.025 mM of DPV, 0.3~2.4 mM of CA, 7.5~480 μM of PEC, and the corresponding detection limits for AA were 1.08 μM (S/N = 3), 0.14 μM (S/N = 3), 0.049 μM (S/N = 3), and 0.084 nA/μM. Moreover, the proposed Cu-TCPP MOFs@GCE electrochemical and photoelectrochemical sensing platform was applied to determine the AA concentration of a real human serum sample; the results reveal that Cu-TCPP MOFs@GCE sensing platform could accurately determine the concentration of AA of the human serum under other potential interferences contained in the human serum samples. Full article

Photodynamic therapy (PDT) combined with upconverting nanoparticles (UCNPs) are viewed together as an effective method of ablating tumors. After absorbing highly tissue-penetrating near-infrared (NIR) light, UCNPs emit a shorter wavelength light (~660 nm) suitable for PDT. In this study, we designed and prepared highly red fluorescence-emitting silica-coated core-shell upconverting nanoparticles modified with polyethylene glycol (PEG_5k)-folic acid and tetrakis(4-carboxyphenyl)porphyrin (TCPP) (UCNPs@SiO₂-NH₂@FA/PEG/TCPP) as an efficient photodynamic agent for killing tumor cells. The UCNPs consisted of two simple lanthanides, erbium and lutetium, as the core and shell, respectively. The unique core-shell combination enabled the UCNPs to emit red light without green light. TCPP, folic acid, and PEG were conjugated to the outer silica layer of UCNPs as a photosensitizing agent, a ligand for tumor attachment, and a dispersing stabilizer, respectively. The prepared UCNPs of ~50 nm diameter and −34.5 mV surface potential absorbed 808 nm light and emitted ~660 nm red light. Most notably, these UCNPs were physically well dispersed and stable in the aqueous phase due to PEG attachment and were able to generate singlet oxygen (¹O₂) with a high efficacy. The HeLa cells were treated with each UCNP sample (0, 1, 5, 10, 20, 30 μg/mL as a free TCPP). The results showed that the combination of UCNPs@SiO₂-NH₂@FA/PEG/TCPP and the 808 nm laser was significantly cytotoxic to HeLa cells, almost to the same degree as naïve TCPP plus the 660 nm laser based on MTT and Live/Dead assays. Furthermore, the UCNPs@SiO₂-NH₂@FA/PEG/TCPP was well internalized into HeLa cells and three-dimensional HeLa spheroids, presumably due to the surface folic acid and small size in conjunction with endocytosis and the nonspecific uptake. We believe that our UCNPs@SiO₂-NH₂@FA/PEG/TCPP will serve as a new platform for highly efficient and deep-penetrating photodynamic agents suitable for various tumor treatments. Full article

Oxidative reactions often require unstable and environmentally harmful oxidants; therefore, the investigation of safer alternatives is urgent. Here, the hydroxylation of aryl boronic acid in the presence of Co-complexes is demonstrated. Tetrakis(4-carboxyphenyl) Co(II)-porphyrin was combined with biodegradable polymers such as chitosan catalyzed hydroxylation of phenyl boronic acids to form phenol derivatives under blue-light irradiation. This catalytic system can be used as an eco-friendly oxidation process that does not release oxidizing agents into the atmosphere. Full article

The photocatalytic reduction of carbon dioxide (CO₂) into CO and hydrocarbon fuels has been considered as an ideal green technology for solar-to-chemical energy conversion. The separation/transport of photoinduced charge carriers and adsorption/activation of CO₂ molecules play crucial roles in photocatalytic activity. Herein, tetrakis (4-carboxyphenyl) porphyrin (H₂TCPP) was incorporated with different metal atoms in the center of a conjugate macrocycle, forming the metalloporphyrins TCPP-M (M = Co, Ni, Cu). The as-obtained metalloporphyrin was loaded as a cocatalyst on commercial titania (P25) to form TCPP-M@P25 (M = Co, Ni, Cu) for enhanced CO₂ photoreduction. Among all of the TCPP-M@P25 (M = Co, Ni, Cu), TCPP-Cu@P25 exhibited the highest evolution rates of CO (13.6 μmol⋅g⁻¹⋅h⁻¹) and CH₄ (1.0 μmol⋅g⁻¹⋅h⁻¹), which were 35.8 times and 97.0 times those of bare P25, respectively. The enhanced photocatalytic activity could be attributed to the improved photogenerated electron-hole separation efficiency, as well as the increased adsorption/activation sites provided by the metal centers in TCPP-M (M = Co, Ni, Cu). Our study indicates that metalloporphyrin could be used as a high-efficiency cocatalyst to enhance CO₂ photoreduction activity. Full article

Ultrafiltration (UF) membranes have found great application in sewage purification and desalination due to their high permeation flux and high rejection rate for contaminants under low-pressure conditions, but the flux and antifouling ability of UF membranes needs to be improved. Tetrakis (4-carboxyphenyl) porphyrin (TCPP) has good hydrophilicity, and it is protonated under strongly acidic conditions and then forms strong hydrogen bonds with N, O and S, so that the TCPP would be well anchored in the membrane. In this work, NaHCO₃ was used to dissolve TCPP and TMC (trimesoyl chloride) was used to produce a strong acid. Then, TCPP was modified in a membrane with a different rejection rate by a method similar to interfacial polymerization. Performance tests of TCPP/polysulfone (PSf) membranes show that for the membrane with a high BSA (bovine serum albumin) rejection, when the ratio of NaHCO₃ to TCPP is 16:1 (wt.%), the pure water flux of membrane Z1 16:1 is increased by 34% (from 455 to 614 Lm⁻²h⁻¹bar⁻¹) while the membrane retention was maintained above 95%. As for the membrane with a low BSA rejection, when the ratio of NaHCO₃ to TCPP was 32:1, the rejection of membrane B2 32:1 was found to increase from 81% to 96%. Although the flux of membrane B2 32:1 decreased, it remained at 638 Lm⁻²h⁻¹bar⁻¹, which is comparable to the reported polymer ultrafiltration membrane. The above dual results are thought to be attributed to the synergistic effect of protonated TCPP and NaHCO₃, where the former increases membrane flux and the latter increases the membrane rejection rate. This work provides a way for the application of porphyrin and porphyrin framework materials in membrane separation. Full article