Tetra 4-carboxyphenyl Porphyrin Research Articles

Visible light-activated dye-sensitized TiO2 antibacterial film: A novel strategy for enhancing food safety and quality

Antibacterial packaging holds promise in addressing food spoilage by inactivating bacteria, but current antimicrobial packaging solutions face challenges like depletion of antibacterials and concerns of antibiotic abuse. In response to these limitations of existing packaging materials, we developed a novel antibacterial packaging film by incorporating titanium dioxide (TiO2)- tetra(4-carboxyphenyl) porphyrin (TcPP) conjugates into cellulose nanofibrils (CNF) films. Unlike conventional antimicrobial packaging, this film harnesses visible light energy to excite electrons from TcPP to TiO2, generating reactive oxygen species (ROS) that inactivate bacteria without relying on antibiotics. Results demonstrated that the film reduced 4.5, 4.6, 4.1, and 4.7-log Escherichia coli, Pseudomonas fluorescens, Leuconostoc lactis, and Listeria innocua, respectively, in phosphate-buffered saline within 72h under 6000 lux light (3.13mW/cm2). The antimicrobial efficacy decreased as the light intensity decreased. Notably, it retains significant antimicrobial properties even under an extremely low light intensity of 600 lux (0.60mW/cm2). The analysis also revealed that singlet oxygen and hydrogen peroxide are the major generated ROS from the film under light exposure. When applied to cucumbers, the film reduced E. coli by 3.5 logs after 48-hour light exposure. The designed photocatalytic antibacterial film represents a major advancement in sustainable food preservation, reducing food waste by extending the shelf life of fresh produce.

Dual-targeting liposomes modified with BTP-7 and pHA for combined delivery of TCPP and TMZ to enhance the anti-tumour effect in glioblastoma cells

Aim To construct a novel nano-carrier with dual ligands to achieve superior anti-tumour efficacy and lower toxic side effects. Methods Liposomes were prepared by thin film hydration method. Ultraviolet, high performance liquid chromatography, nano-size analyser, ultrafiltration centrifugation, dialysis, transmission electron microscope, flow cytometry, Cell Counting Kit-8, confocal laser scanning microscopy, transwell, and tumorsphere assay were used to study the characterisations, cytotoxicity, and in vitro targeting of dg-Bcan targeting peptide (BTP-7)/pHA-temozolomide (TMZ)/tetra(4-carboxyphenyl)porphyrin (TCPP)-Lip. Results BTP-7/pHA-TMZ/TCPP-Lip was a spheroid with a mean diameters of 143 ± 3.214 nm, a polydispersity index of 0.203 ± 0.025 and a surface charge of −22.8 ± 0.425 mV. The drug loadings (TMZ and TCPP) are 7.40 ± 0.23% and 2.05 ± 0.03% (mg/mg); and the encapsulation efficiencies are 81.43 ± 0.51% and 84.28 ± 1.64% (mg/mg). The results showed that BTP-7/pHA-TMZ/TCPP-Lip presented enhanced targeting and cytotoxicity. Conclusion BTP-7/pHA-TMZ/TCPP-Lip can specifically target the tumour cells to achieve efficient drug delivery, and improve the anti-tumour efficacy and reduces the systemic toxicity.

A hybrid linker-MOF fibrous composite for efficient diclofenac removal and self-cleaning

The treatment of emerging contaminants is essential but challenging. Herein, a novel MOF/PAN fibrous composite (TCPP@UiO-66/PAN) was synthesized and used as a self-cleaning membrane for the efficient removal of a typical emerging contaminant, diclofenac sodium (DF). The introduction of the secondary linker tetra(4-carboxyphenyl)porphyrin (TCPP) served to expand the pores and enhance its photocatalytic activity. TCPP@UiO-66/PAN shows higher adsorption capacity and initial adsorption rate than UiO-66/PAN. The maximum adsorption capacity of DF on TCPP@UiO-66/PAN reached 202 mg/g by Langmuir model. The DF adsorption mechanism involves the π-π/anion-π interaction, Lewis acid-base interaction, and hydrogen bonding. Based on the dynamic filtration experiment, TCPP@UiO-66/PAN exhibited a remarkable treatment capacity for DF-contaminated water, measuring 3.75 × 104kg/kg. Given its fibrous membrane structure, TCPP@UiO-66/PAN could be easily separated from water and reused. In-situ photo-regeneration emerged as a highly effective method for regenerating TCPP@UiO-66/PAN after reaching adsorption saturation, with over 95 % DF degradation achieved under sunlight irradiation. The decomposition of DF primarily resulted from the generation of h+and1O2. Additionally, TCPP@UiO-66/PAN exhibited notable antibacterial properties when exposed to visible light.In vitrocytotoxicity assessments further confirmed the safety of these MOF/PAN composites. Combining the advantages of hybrid-linker strategy and fibrous composite, this work provided new insight into constructing MOF-based functional material for wastewater purification.

Chiral Metal-Organic Framework with Temperature-Dependent Homochirality for Chiral Discrimination.

Chiral metal-organic frameworks (CMOFs) have attracted considerable attention in chiral discrimination and separation. In this work, a simple CMOF is synthesized through a facile one-pot method by using Zn(II), tetra(4-carboxyphenyl)-porphyrin (TCPP), and d-phenylalanine methyl ester (d-Phe-OMe) as metal ion, organic ligand, and chiral source, respectively. Interestingly, the CMOFs synthesized at different temperatures (25 and 160 °C) display quite different morphologies and diametrically opposite chirality due to the different interaction modes between TCPP and d-Phe-OMe at 25 and 160 °C. Next, the CMOFs synthesized at 25 and 160 °C are utilized for the chiral discrimination of the isomers of tryptophan (Trp), resulting in exactly the reverse effect. The developed CMOF-based chiral sensors also exhibit excellent reproducibility, suggesting their great potential for chiral analysis.

Spectroscopic Investigations of Porphyrin-TiO2 Nanoparticles Complexes

This study presents the spectral characterization of TiO2 nanoparticles (NPs) functionalized with three porphyrin derivatives: 5,10,15,20-(Tetra-4-aminophenyl) porphyrin (TAPP), 5,10,15,20-(Tetra-4-methoxyphenyl) porphyrin (TMPP), and 5,10,15,20-(Tetra-4-carboxyphenyl) porphyrin (TCPP). UV-Vis absorption and Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR) spectroscopic studies of these porphyrins and their complexes with TiO2 NPs were performed. In addition, the efficiency of singlet oxygen generation, the key species in photodynamic therapy, was investigated. UV-Vis absorption spectra of the NPs complexes showed the characteristic bands of porphyrins. These allowed us to determine the loaded porphyrins on TiO2 NPs functionalized with porphyrins. FTIR-ATR revealed the formation of porphyrin-TiO2 complexes, suggesting that porphyrin adsorption on TiO2 may involve the pyrroles in the porphyrin ring, or the radicals of the porphyrin derivative. The quantum yield for singlet oxygen generation by the studied porphyrin complexes with TiO2 was higher compared to bare porphyrins for TAPP and TMPP, while for the TCPP-TiO2 NPs complex, a decrease was observed, but still maintained a good efficiency. The TiO2 NPs conjugates can be promising candidates to be tested in photodynamic therapy in vitro assays.

Photocatalytic Degradation of Methylene Blue under Visible Light Using TiO2 Thin Films Impregnated with Porphyrin and Anderson-Type Polyoxometalates (Cu and Zn)

In this work, tetra(4-carboxyphenyl)porphyrin (TCPP) and two Anderson-type polyoxomolybdates (containing Cu and Zn, respectively; CuPOM, ZnPOM) were synthesized and deposited on TiO2 thin films. The properties of the obtained materials were characterized through UV–vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR), diffuse reflection spectroscopy, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The adsorption and photodegradation under the visible light irradiation of methylene blue (MB) were studied for TiO2, TCPP/TiO2, TCPP/CuPOM/TiO2 and TCPP/ZnPOM/TiO2 thin films in aqueous solution. The results of the diffuse reflectance showed two bands in the visible light spectrum for the TCPP/POM/TiO2 systems compared to unmodified TiO2 that does not show any bands in the same region of the spectrum. The TCPP/POM/TiO2 systems showed a higher removal of MB, with an adsorption rate near to 31% for the TCPP/CuPOM/TiO2 film compared to 9% adsorption on the TiO2 film. The kinetic results show that the pseudo-second order model was the best fitting model for the MB adsorption process onto fabricated materials. The photodegradation studies under visible light showed a better performance on TCPP/POM/TiO2 thin films, with an efficiency in the MB photodegradation of near 49% and 44% in aqueous solution for TCPP/CuPOM/TiO2 and TCPP/ZnPOM/TiO2, respectively. The reusability test indicated that the porphyrin films are moderately stable after the performed cycles.

Eco-friendly fabrication of porphyrin@hyperbranched polyamide-amine@phytic acid/PVDF membrane for superior oil-water separation and dye degradation

The treatment of oily wastewater containing water-soluble dyes has drawn attention and become a thorny issue. Aiming at removing oil droplets and dyes from wastewater, it is reported in this work the design of polyelectrolyte deposited dual functional membrane with superior separation and degradation capabilities. The hyperbranched polyamide-amine (HPAMAM) was combined with tetra (4-carboxyphenyl) porphyrin (TCPP) and phytic acid (PA) through electrostatic interaction to form an eco-friendly polyelectrolyte complex by one-step self-assembly method. Relying on affluent amine group and unique cavity structure as well as wide range of delocalized π-electron systems, TCPP@HPAMAM@PA possesses robust water binding ability and intense absorption in the visible region, endowing PVDF membrane with superhydrophilicity/underwater superoleophobicity, oil resistance and superior photocatalytic degradation properties. The dual functional TCPP@HPAMAM@PA/PVDF membranes can realize superb removal of oil droplets (oil rejection > 99 %) at high flux recovery rate with several cycles. Furthermore, the degradation efficiency of rhodamine B (RhB) and Methyl blue (MB) reaches 93 % and 96 % respectively, showing standout photocatalytic degradation performance. A facile and low-energy strategy for the modification of commercial PVDF membranes is proposed, which is not only consistent with the concept of green chemistry but also has a broad application in the separation of complex oily wastewater systems.

Red-Emissive Sulfur-Doped Carbon Dots for Selective and Sensitive Detection of Mercury (II) Ion and Glutathione.

Carbon dots (CDs) show great potential in bioimaging and biosensing because of their good biocompatibility and excellent optical properties. However, CDs with intense red emissions for sensitive and selective detection are rarely reported. Herein, we prepared the red-emissive carbon dots (RCDs) through a facile hydrothermal method using tetra (4-carboxyphenyl) porphyrin (TCPP) and thiourea as starting materials. The obtained RCDs were characterized by TEM, XRD, and XPS. RCDs exhibited high water solubility and strong red emission (λem = 650 nm), with the fluorescence quantum yield as high as 26.7%, which was greatly higher than that of TCPP. Moreover, the as-prepared RCDs could be acted as a highly selective and sensitive probe for the detection of Hg2+ and glutathione (GSH) through the fluorometric titration method. The detection limits of Hg2+ and GSH were calculated to be 1.73 and 1.6 nM, respectively. The cellular experiments demonstrated the good biocompatibility of RCDs and their feasibility in bioimaging. Thus, this work provided a simple strategy to design and synthesize the highly red-emissive carbon dots, which showed promising application in biological and environmental assays.

Spectroscopic investigation of the electronic and excited state properties of para-substituted tetraphenyl porphyrins and their electrochemically generated ions

Porphyrins play pivotal roles in many crucial biological processes including photosynthesis. However, there is still a knowledge gap in understanding electronic and excited state implications associated with functionalization of the porphyrin ring system. These effects can have electrochemical and spectroscopic signatures that reveal the complex nature of these somewhat minor substitutions, beyond simple inductive or electronic effect correlations. To obtain a deeper insight into the influences of porphyrin functionalization, four free-base, meso-substituted porphyrins: tetraphenyl porphyrin (TPP), tetra(4-hydroxyphenyl) porphyrin (THPP), tetra(4-carboxyphenyl) porphyrin (TCPP), and tetra(4-nitrophenyl) porphyrin (TNPP), were synthesized, characterized, and investigated. The influence of various substituents, (-hydroxy,-carboxy, and -nitro) in the para position of the meso-substituted phenyl moieties were evaluated by spectroelectrochemical techniques (absorption and fluorescence), femtosecond transient absorption spectroscopy, cyclic and differential pulse voltammetry, ultraviolet photoelectron spectroscopy (UPS), and time-dependent density functional theory (TD-DFT). Spectral features were evaluated for the neutral porphyrins and differences observed among the various porphyrins were further explained using rendered frontier molecular orbitals pertaining to the relevant transitions. Electrochemically generated anionic and cationic porphyrin species indicate similar absorbance spectroscopic signatures attributed to a red-shift in the Soret band. Emissive behavior reveals the emergence of one new fluorescence decay pathway for the ionic porphyrin, distinct from the neutral macrocycle. Femtosecond transient absorption spectroscopy analysis provided further analysis of the implications on the excited-state as a function of the para substituent of the free-base meso-substituted tetraphenyl porphyrins. Herein, we provide an in-depth and comprehensive analysis of the electronic and excited state effects associated with systematically varying the induced dipole at the methine bridge of the free-base porphyrin macrocycle and the spectroscopic signatures related to the neutral, anionic, and cationic species of these porphyrins.

Rationally designed tetra (4-carboxyphenyl) porphyrin/graphene quantum dots/bismuth molybdate Z-scheme heterojunction for tetracycline degradation and Cr(VI) reduction: Performance, mechanism, intermediate toxicity appraisement

Constructing novel Z-scheme heterojunctions is an effective strategy for obtaining high-performance photocatalysts. Herein, tetra (4-carboxyphenyl) porphyrin (TCPP) and graphene quantum dots (GQDs) were loaded on the surface of Bi2MoO6 (BMO) to fabricate novel Z-scheme heterojunctions of TCPP/G/BMO. Especially, TCPP/G/BMO-2 showed an exceptional visible-light photoactivity for tetracycline (TC) degradation (81.0%, 40 min) and Cr(VI) reduction (90.7%, 60 min), respectively by 2.38 folds and 2.96 folds enhancement compared to sole Bi2MoO6. The substantial enhancement of activity is attributed to the synergy effect of the Z-scheme charge transfer mechanism and the improved light absorption. The degradation pathways of TC were inferred by determining the generated intermediates using high performance liquid chromatography-mass spectrometry (HPLC-MS), and the toxicity of the transformation products was assessed by Toxicity Estimation Software Tool (T.E.S.T). Overall, on the basis of trapping experiments and electron spin resonance spectra (ESR) analysis, the photocatalytic mechanisms of Cr(VI) reduction and TC degradation by the TCPP/G/BMO Z-scheme heterojunction was proposed. This work indicates TCPP/G/BMO could be a promising photocatalyst for wastewater treatment.

Facile construction of novel organic–inorganic tetra (4-carboxyphenyl) porphyrin/Bi2MoO6 heterojunction for tetracycline degradation: Performance, degradation pathways, intermediate toxicity analysis and mechanism insight

Developing durable photocatalysts with highly efficient antibiotics degradation is crucial for environment purification. Herein, tetra (4-carboxyphenyl) porphyrin (TCPP) was loaded onto the surface of Bi2MoO6 microspheres to gain hierarchical organic–inorganic TCPP/Bi2MoO6 (TCPP/BMO) heterojunctions via a facile impregnation strategy. The catalytic properties of these catalysts were comprehensively investigated through the photodegradation of tetracycline hydrochloride (TC) under visible light. Among all the TCPP/BMO heterojunctions, the highest photodegradation rate constant (0.0278 min−1) was achieved with 0.25 wt% TCPP (TCPP/BMO-2), which was approximately 1.15 folds greater than that of pristine Bi2MoO6 and far superior to pure TCPP. The extremely high photocatalytic performance is attributed to the interfacial interaction between TCPP and Bi2MoO6, which favors the efficient separation of charge carriers and the enhancement of visible-light absorbance. TCPP/BMO-2 possesses high mineralization capability and good recycling performance. Photo-induced O2–, h+, and OH were mainly responsible for the degradation of TC. The degradation pathways of TC and toxicity of degradation intermediates were analyzed based on the intermediates detected by the high performance liquid chromatography-mass spectrometer (HPLC–MS) and the toxicity assessment by the quantitative structure–activity relationship (QSAR) prediction. A possible photocatalytic mechanism over TCPP/BMO is proposed. This work offers an insight in developing the porphyrin-based organic–inorganic heterojunctions for effectively remedying pharmaceutical wastewater.

Evaluation of visible-light driven photocatalytic reaction by porphyrin coupled TiO2 nanotubes obtained via rapid breakdown anodization

The perceived attraction of nanotubular TiO2 in diverse applications has brought the researchers attention to focus on various aspects of nanotube synthesis and modification. In this work, the visible light activity of dye sensitized TiO2 nanotubes obtained in powder form via rapid breakdown anodization was investigated. Tetra (4-carboxy phenyl) porphyrin (TCPP) was used as a visible light sensitizing component on phase pure anatase TiO2 nanotubes (ATiNT). The effect of introducing two different anchoring groups between the dye and TiO2 nanotubes on photocatalytic activity was investigated. The visible light photocatalytic efficiency of the prepared ATiNT/TCPP composites was tested on a pharmaceutical compound, famotidine (FAM) in order to avoid degradation through photosensitization. For the given amount of TCPP load on ATiNT, the presence of a lengthy anchoring group between TCPP and ATiNT had a negative influence on the photocatalytic activity. Direct oxidation through visible-light-generated holes in the ATiNT/TCPP composite appeared to be the most significant pathway for FAM photocatalysis.

The critical role of Tween 80 as a ‘green’ template on the physical properties and photocatalytic performance of TiO2 nanoparticles for Rhodamine B photodegradation

A popular non-toxic surfactant, Tween 80 (T80), is widely used in foods, cosmetics, and pharmaceuticals. This eco-friendly surfactant should be promising to be utilized as a non-ionic template in the preparation of TiO2 nanoparticles. Moreover, few studies deal with Tween 80 as a template in the synthesis of various nanoparticles. Different concentrations of T80/isopropanol solutions (0–50%) were used in a modified template-assisted sol–gel route, where the synthesized xerogels were denoted by x%T80-TiO2. Different techniques such as DRS, XRD, SEM, HR-TEM, and N2 adsorption–desorption isotherms were utilized to characterize the as-prepared x%T80-TiO2 catalysts. The obtained results showed that the whole physical properties, such as crystalline parameters, optical properties, micromorphology, nanomorphology, and surface parameters, were affected by the concentration of T80 (T80%). In addition, T80% significantly changed the photoactivity of the synthesized samples toward the photodegradation of Rhodamine B (RB) as a pollutant model. 5%T80-TiO2 nanoparticles were the most reactive catalyst referring to its unique rod structure and existence of a small content of Rutile phase. Finally, tetra (4-carboxyphenyl) porphyrin (TCPP) was anchored on TiO2 nanorods to be used as a visible antenna to enhance its photocatalytic activity toward the visible light irradiation. Briefly, TCPP-sensitized T80-TiO2 nanoparticles showed an enhanced performance toward the degradation of RB under various light sources.

Mitochondria-targeted tri-triphenylphosphonium substituted meso-tetra(4-carboxyphenyl)porphyrin(TCPP) by conjugation with folic acid and graphene oxide for improved photodynamic therapy

Mitochondria are extensively researched as target sites to maximize photodynamic therapy (PDT) effects because they play crucial roles in metabolism. Here, a mitochondria targeting PDT agent, tri-triphenylphosphonium substituted meso-tetra(4-carboxyphenyl)porphyrin (TCPP-TPP) is prepared for the first time. Considering that many porphyrin derivatives are quick to aggregate, thereby reducing the PDT effect, our photosensitizer (PS) was loaded on a folic acid (FA) decorated graphene oxide (GO) nanosystem, called GF@TCPP-TPP, by electrostatic and [Formula: see text]–[Formula: see text] stacking or hydrophobic cooperative interactions, to improve the transportation of photosensitizers and enhance the therapeutic effect. Herein, we have performed a detailed study of photodynamic activity of GF@TCPP-TPP nanocomposites and evaluated their potential as a photosensitizer in PDT. An MTT assay showed that GF@TCPP-TPP inhibited HeLa cells in a concentration-dependent manner under light (650 ± 10 nm, 5 mW [Formula: see text] and 10 min), and presented remarkably improved PDT efficiency (IC[Formula: see text] g [Formula: see text] mL[Formula: see text] of equivalent TCPP-TPP) over free TCPP (IC[Formula: see text] after irradiation. Furthermore, our research indicated that Type I mechanisms (the generation of hydroxyl radicals) play a predominant role in the GF@TCPP-TPP induced PDT process. This coincides with the low singlet oxygen (1O[Formula: see text] quantum yield ([Formula: see text] [Formula: see text] 33.6%) in a DMF solution. Moreover, cell morphological changes after GF@TCPP-TPP PDT further demonstrated that GF@TCPP-TPP could induce damage and apoptotic cell death efficiently. In particular, precise delivery of photosensitizers to mitochondria was proven by organelle localization.

Effect of porphyrin on photocatalytic activity of TiO2 nanoparticles toward Rhodamine B photodegradation

As known, porphyrins have central role in photosynthesis, biological oxidation and reduction and oxygen transport beside to their intensive color which qualify them to be good photosensitizers. Herein, tetra (4-carboxyphenyl) porphyrin (TCPP) was prepared by a simple one-pot synthesis to use as a visible antenna for TiO2 nanoparticles that were prepared via a simple template-free sol-gel method. Various loading percentages of TCPP (0.05–1%) were incorporated on the surface of TiO2 as photosensitizer for photocatalytic degradation of Rhodamine B (Rh B) dye as a primary cationic pollutant model. Among them, 0.1% TCPP-TiO2 was the most reactive sample. It was found that the photoactivity of 0.1% TCPP-TiO2 sample (0.5g/L) was approximately 1.5 times greater than that of pure TiO2 (0.5g/L) toward the degradation of Rh B (1×10−5M) under UV-A irradiation. Transient fluorescence decay measurements showed that the life time of TiO2 excited state has doubled after anchoring TCPP, thus the probability of electron-hole recombination has decreased. The samples were characterized by XRD, HR-TEM, DRS and N2 adsorption-desorption isotherms. The XRD patterns confirmed the successful preparation of TiO2 nanoparticles with average crystalline size of 25.7nm. Also, XRD patterns suggested the presence of mixed phase TiO2 nanoparticles of 77% anatase and 23% rutile. DRS showed that the characteristic peaks of TCPP covered the whole visible range 400–700nm. HR-TEM images showed the spheroids shape of TiO2 nanoparticles and confirmed the presence of anatase and rutile phases as suggested from XRD data. The different parameters affecting the photodegradation of Rh B dye such as catalyst dose, dye concentration and pH were studied to obtain the optimum conditions. Almost complete degradation of Rh B was obtained which confirmed by HPLC and TOC measurements. The effect of scavengers was studied to indicate the most active species. TCPP-TiO2 gave a good response toward the photodegradation of Rh B under visible irradiation. Finally, the mechanism of photocatalytic degradation process was suggested.

Enhanced visible light photocatalytic hydrogen evolution over porphyrin hybridized graphitic carbon nitride

Tetra (4-carboxyphenyl) porphyrin (TCPP) was loaded on the surface of Pt/g-C3N4 via a simple adsorption process, and the microstructure and chemical structure of the composites were characterized by high resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, UV–visible diffused reflectance spectroscopy and photoluminescence spectroscopy. Loading TCPP onto Pt/g-C3N4 enhanced the visible-light-driven photocatalytic evolution of H2 from water. The TCPP/Pt/g-C3N4 composite with a TCPP loading of 1wt% had the highest photoactivity, which was 2.1 times higher than that of Pt/g-C3N4. This improvement is attributed to enhanced visible light utilization by the TCPP/Pt/g-C3N4 resulting from the strong visible light response of TCPP. In addition, the formed organic heterostructure between TCPP and g-C3N4 with overlapping bad gaps accelerates the electron transfer and inhibits the recombination of the photogenerated electrons and holes on g-C3N4.

Plasmon‐Enhanced Fluorescence‐Based Core–Shell Gold Nanorods as a Near‐IR Fluorescent Turn‐On Sensor for the Highly Sensitive Detection of Pyrophosphate in Aqueous Solution

Developing plasmon‐enhanced fluorescence (PEF) technology for identifying important biological molecules has a profound impact on biosensing and bioimaging. However, exploration of PEF for biological application is still at a very early stage. Herein, novel PEF‐based core–shell nanostructures as a near‐infrared fluorescent turn‐on sensor for highly sensitive and selective detection of pyrophosphate (PPi) in aqueous solution are proposed. This nanostructure gold nanorod (AuNR)@SiO2@meso‐tetra(4‐carboxyphenyl) porphyrin (TCPP) contains a gold nanorod core with an aspect ratio of 2.3, a silica shell, and TCPP molecules covalently immobilized onto the shell surface. The silica shell is employed a rigid spacer for precisely tuning the distance between AuNR and TCPP and an optimum fluorescence enhancement is obtained. Due to the quenching effect of Cu2+, the copper porphyrin (TCPP‐Cu2+) results in a weak fluorescence. In the presence of PPi, the strong affinity between Cu2+ and PPi can promote the disassembly of the turn‐off state of TCPP‐Cu2+ complexes, and therefore the fluorescence can be readily restored. By virtue of the amplified fluorescence signal imparted by PEF, this nanosensor obtains a detection limit of 820 × 10−9m of PPi with a good selectivity over several anions, including phosphate. Additionally, the potential applicability of this sensor in cell imaging is successfully demonstrated.

Early Detection of Lung Cancer with Meso Tetra (4-Carboxyphenyl) Porphyrin-Labeled Sputum

Early detection of lung cancer in high-risk individuals reduces mortality. Low-dose spiral computed tomography (LDCT) is the current standard but suffers from an exceedingly high false-positive rate (>96%) leading to unnecessary and potentially dangerous procedures. We, therefore, set out to develop a simple, noninvasive, and quantitative assay to detect lung cancer. This proof-of-concept study evaluated the sensitivity/specificity of the CyPath Early Lung Cancer Detection Assay to correctly classify LDCT-confirmed cohorts of high-risk control (n = 102) and cancer (n = 26) subjects. Fluorescence intensity parameters of red fluorescent cells (RFCs) from tetra (4-carboxyphenyl) porphyrin (TCPP)-labeled lung sputum samples and subjects' baseline characteristics were assessed for their predictive power by multivariable logistic regression. A receiver operating characteristic curve was constructed to evaluate the sensitivity/specificity of the CyPath assay. RFCs were detectable in cancer subjects more often than in high-risk ones (p = 0.015), and their characteristics differed between cohorts. Two independent predictors of cancer were the mean of RFC average fluorescence intensity/area per subject (p < 0.001) and years smoked (p = 0.003). The CyPath-based classifier had an overall accuracy of 81% in the test population; false-positive rate of 40% and negative predictive value of 83%. The tetra (4-carboxyphenyl) porphyrin -based CyPath assay correctly classified study participants into cancer or high-risk cohorts with considerable accuracy. Optimizing sputum collection, sample reading, and refining the classifier should improve sensitivity and specificity. The CyPath assay thus has the potential to complement LDCT screening or serve as a stand-alone approach for early lung cancer detection.

The visible light degradation activity and the photocatalytic mechanism of tetra(4-carboxyphenyl) porphyrin sensitized TiO2

Tetra(4-carboxyphenyl) porphyrin(TCPP) were chemically sensitized on TiO2 to act as visible light antenna and to modify the photoresponse properties of TiO2 particles, their properties of photo-generated holes and electrons were studied by transient absorption spectroscopes. The time-correlated single-photon counting (TCSPC) technique revealed that the S2–S0 fluorescence intensity of TCPP is enhanced noticeably by TiO2, and the lifetime prolonged. Adsorption and photo degradation of methylene blue (MB) over TCPP-TiO2 were systematically investigated. Moreover the overall picture of electronic relaxation dynamics for TCPP-TiO2 is presented, and the detailed short-time dynamics for visible-light induced catalytic mechanism was discussed. The development of the porphyrin-based photocatalyst provides an alternative approach in harnessing solar visible light and show promising prospect for the treatment of dye pollutants from wastewaters in future industrial application.

Layer-by-Layer Growth and Photocurrent Generation in Metal–Organic Coordination Films

A series of metal–organic coordination films with tetra(4-carboxyphenyl)porphyrin (TCPP) and trimesic acid (TMA) ligands and Cu2+ ion linkers were grown layer-by-layer on TiO2-modified indium tin oxide electrodes and the cathodic short-circuit photocurrent that they generate was studied. The layer-by-layer growth was verified by using absorption spectroscopy in the visible and X-ray photoelectron spectroscopy, highlighting the consistent coverage of TCPP in each layer. The photocurrent increases nonlinearly with the number of TCPP layers and with the number of TMA layers introduced as a buffer between TCPP and substrate. These observations are rationalized by considering substrate screening of the TCPP photoexcited state and charge transport across the metal–organic multilayers.