Macrocyclic Organic Compounds Research Articles

Development of Red-Emissive Porphyrin Graphene Quantum Dots (PGQDs) for Biological Cell-Labeling Applications.

Red and near-infrared emission is a highly desirable feature for fluorescent nanoparticles in biological applications mainly due to longer wavelengths more easily being able to deeply penetrate tissues, organs, skin, and other organic components, while less autofluorescence interference would be produced. Additionally, graphene quantum dots (GQDs) that contain unique optical and electrical features have been targeted for their use in cell labeling applications as well as environmental analysis. Their most desirable features come in the form of low toxicity and biocompatibility; however, GQDs are frequently reported to have blue or green emission light and not the more advantageous red/NIR emission light. Furthermore, porphyrins are a subgroup of heterocyclic macrocycle organic compounds that are also naturally occurring pigments in nature that already contain the desired red-emission fluorescence. Therefore, porphyrins have been used previously to synthesize nanomaterials and for nanoparticle doping in order to incorporate the red/NIR emission light property into particles that otherwise do not contain the desired emission light. Meso-tetra(4-carboxyphenyl)porphine (TCPP) is one type of porphyrin with a large conjugated π-electron system and four carboxyl groups on its exterior benzene rings. These two key characteristics of TCPP make it ideal for incorporation into GQDs, as it would design and synthesize red-emissive material as well as give rise to excellent water solubility. In this work, TCPP is used in tangent with cis-cyclobutane-1,2-dicarboxylic acid (CBDA-2), a biomass derived organic molecule, to synthesize "green" porphyrin-based graphene quantum dots (PGQDs) with red-emission. The obtained PGQDs were characterized by various analytical methods. Utilizing TEM, HRTEM, and DLS the size distribution of the particles was determined to be 7.9 ± 4.1, well within the quantum dot range of 2-10 nm. FT-IR, XPS, and XRD depicted carbon, nitrogen, and oxygen as the main elemental components with carbon being in the form of graphene and the main porphyrin ring of TCPP remaining present in the final PGQDs product. Lastly, absorption and fluorescence spectroscopy determined the excitation wavelength at 420 nm and the emission at 650 nm which was successfully utilized in the imaging of HeLa cells using confocal microscopy.

Porphyrin‐Based Nanostructures for Cancer Theranostics: Chemistry, Fundamentals and Recent Advances

AbstractAs heterocyclic macrocycle organic compounds, porphyrins can generate a rich platform of chemical behavior and characteristics conveniently utilized for multiple bioapplications, including bio‐sensors, fluorescence tracking, and in vivo imaging. The conjugation of nanotechnology and porphyrins presents a promising approach to enhance the safety and effectiveness of porphyrin‐based materials in phototherapy against cancer. Several nanoformulations, including organic and inorganic nanocarriers, porphyrin‐laden nanoparticles, porphyrin‐based amphiphilic molecules, supramolecular polymers, and porphyrin‐based block copolymers, have been investigated to deliver porphyrins, which protect the pre‐mature release of photosensitizer and provide tumor‐selective and site‐specific targeting. The monodisperse nanoparticles formed of biocompatible building block conjugates can be beneficially used to develop a multifunctional novel system utilized in optical imaging, positron emission tomography, photodynamic therapy, photothermal therapy, and other imaging modalities in one formulation. This topic is important because exploiting and knowing porphyrin‐based nanostructures aids in detecting pathological damages that cannot readily be discovered by routine imaging or physical examination and thus, helps early diagnosis of cancer. This critical review will assess the basic knowledge and updated information for a broad audience of scientists, engineers, and newcomers related to the porphyrin‐based nanostructures for cancer theranostics

Thallium in aquatic environments and the factors controlling Tl behavior.

Although thallium (Tl) usually exists in a very low level in the natural environment, it is highly toxic. With the development of mining and metallurgical industry and the wide application of Tl in the field of high technologies, Tl poses an increasing threat to the ecological environment and human health. This paper summarizes the research results of the toxicity of Tl as well as the distribution, occurrence forms, migration, and transformation mechanism of Tl in rivers, lakes, mining areas, estuaries, coastal waters, and oceans. It also discusses the influence mechanisms of pH, redox potential, suspended particulate matters, photochemical reaction, natural minerals, cation/anion, organic matters, and microorganisms on the environmental behavior of Tl. This paper points out the shortcomings of Tl research methods in water environment, and looks forward to the future development directions: First, the technology for separating Tl(III) and Tl(I) is still immature, especially it is difficult to effectively separate Tl(III) and Tl(I) in seawater. Second, the development of many advanced in situ detection technologies will bring great convenience to the studies of the dynamic mechanisms of Tl migration and transformation in the environments. Third, adsorption is the most effective mechanism to remove Tl from water, in which modified metal oxides or macrocyclic organic compounds have high application potential.

Cationic Nonporous Macrocyclic Organic Compounds for Multimedia Iodine Capture.

Over the past two decades, progress in chemistry has generated various types of porous materials for removing iodine (129 I or 131 I) that can be formed during nuclear energy generation or nuclear waste storage. However, most studies for iodine capture are based on the weak host-guest interactions of the porous materials. Here, we present two cationic nonporous macrocyclic organic compounds, namely, MOC-1 and MOC-2, in which 6I- and 8I- were as counter anions, for highly efficient iodine capture. MOC-1 and MOC-2 were formed by reacting 1,1'-diamino-4,4'-bipyridylium di-iodide with 1,2-diformylbenzene or 1,3-diformylbenzene, respectively. The presence of a large number of I- anions results in high I2 affinity with uptake capacities up to 2.15 g ⋅ g-1 for MOC-1 and 2.25 g ⋅ g-1 for MOC-2.

CO2 Separation Properties of a Ternary Mixed-Matrix Membrane Using Ultraselective Synthesized Macrocyclic Organic Compounds

Extra-high-performance low-level filler-loaded mixed-matrix membranes (MMMs) were fabricated by embedding a flexible cyclooligomer, calix[4]arene (CA), as a macrocyclic porous filler in two blends of a commercial polyether block amide polymer, Pebax MH 1657. Two kinds of liquid phases, PEG550 (PEG) and [OMIM][PF₆] (IL), were separately introduced into the Pebax MH 1657 matrix to prepare blended membranes for enhancing the CO₂ permeability and comparing their performance. Afterward, CA as the third generation of supramolecular hosts with high inherent affinity to CO₂ was synthesized and incorporated in the polymer blends to fabricate high-performance MMMs. The organic nature, the high compatibility of other applied additives with Pebax MH 1657 polymer, and the tiny size of CA particles were responsible for the desirable particle distribution in ternary MMMs. In the case of the Pebax/PEG550 (30 wt%)/CA (0.5 wt%) MMM, the results revealed the CO₂ permeability to be about 632.60 Barrer, with CO₂/CH₄ and CO₂/N₂ selectivities about 59.83 and 139.88, respectively. For Pebax/IL (6.5 wt%)/CA (0.5 wt%), the CO₂ permeability was about 263.82 Barrer, with CO₂/CH₄ and CO₂/N₂ selectivities about 64.39 and 152.45, respectively. Therefore, the fabricated ternary MMMs present a promising outlook for CO₂ separation, which surpasses the Robeson upper limits.

Photonically-Activated Molecular Excitations for Thermal Energy Conversion in Porphyrinic Compounds

Heterocyclic, macrocycle organic compounds, structurally characterized with porphyrins, are not only abundant in nature but also environmentally friendly. These porphyrinic compounds have recently been extensively studied for their fascinating structures, physical properties, and high potentials in engineering applications. We report experimental results on the photonically activated thermal energy conversion via irradiations of white light (simulated solar light). The photothermal effects have been well studied for metallic conductors with a large number of charge carriers based on the so-called localized surface plasmon resonance (LSPR). However, the LSPR model may not apply to the porphyrinic materials with a very limited number of charge carriers. In this study, we have found several porphyrinic compounds to exhibit pronounced photothermal effects including chlorophyll, chlorophyllin, hemoglobin, and phthalocyanine, which all share similar structural characteristics. Raman data show characteristic mol...

Reviewing of metalloporphyrins as novel catalysts for synthesis of conducting and water-soluble polymers

Porphyrins are a group of heterocyclic macrocycle organic compounds, composed of four modified pyrrole subunits interconnected at their α carbon atoms via methine bridges (=CH−). Porphyrins have attracted much attention because of their unique structures and a wide spectrum of very useful physicochemical and biological properties, such as anion binding, stabilization of metal ions with unusual oxidation states, electron transfer, and construction of peculiar supramolecular assemblies. The synthesis of electroactive and water-soluble polymers were accomplished with water-soluble metal(III) porphyrins in the presence of a template. The polymerization by matelloporphyrin is simple (one-step), chemically mild, and environmentally benign and requires minimal separation. This approach provides a distinct advantage over similar reactions employing native enzymes due to higher stability and lower price of the catalysts.

Abstract 3213: Evaluation of porphyrin biodistribution for use in photodynamic therapy of retinoblastoma in transgenic mice

Abstract Background: Porphyrins are a group of heterocyclic macrocycle organic compounds. They have shown good efficiency in the photodynamic treatment of tumors in the last twenty years. The photodynamic therapy could be an alternative treatment for retinoblastoma using a photosensitizer with low dark toxicity and low mutagenic properties unlike the conventional chemotherapies. The objectives of this study were to develop a photosensitizer in our lab which is a diethylene glycol mannoconjugated tetraphenyl porphyrin (TPP, MW: 1413.6) and to determine the optimal interval time for photodynamic therapy using the concentration of TPP in eye and blood samples of mice. Materials and method: Transgenic mice developed bilateral retinoblastoma from the retina since 4 weeks of age to 16 weeks of age (tumors fill the ocular globe and the mice will be sacrificed for ethic purpose). The evaluation of the biodistribution of our TPP was realized to know the best drug-light interval to perform the photodynamic therapy. For this purpose, an intraperitoneal injection of 200 µl at 5.25 mg/ml in PEG 400/physiological serum (1:1, v/v) was performed on the LHbetaTag transgenic mice. At different time intervals (8h, 24h, 40h, 48h, and 72h) following injection, the mice were sacrificed and the eyes and blood were collected. TPP in eye samples were extracted in methanol and the level of TPP was measured by ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) analysis (0.5-100 ng/mL). The level of TTP in blood samples was quantified after protein precipitation by UPLC-MS/MS method (5.00-1000 ng/mL). Results: We observed a time dependency accumulation of TPP in eyes with observed Tmax=48 hours. TPP serum concentrations decreased by the same manner up to 48 h. The determination of drug-light interval allowed us to perform the light delivery when the TPP level is highest (48 h) in the ocular tumor tissue (retinoblastoma). Conclusions: Our TPP had a good in vitro photocytotoxicity at very low doses and showed a good efficacy in vivo with subcutaneous patient derived retinoblastoma xenografts in immunodeficient mice. The knowledge of Tmax and this interval is essential to realize the photodynamic therapy with the better efficiency, the final goal being to eradicate the retinoblastoma from the retina. Citation Format: Florent Poyer, Samuel Hugeut, Stéphanie Lemaitre, Olivier Madar, Carole D Thomas, Philippe Maillard, Marie-Paule Teulade-Fichou, Nathalie Cassoux, François Doz, Keyvan Rezai. Evaluation of porphyrin biodistribution for use in photodynamic therapy of retinoblastoma in transgenic mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3213.

Fabric Based Wearable Biosensor for Continuous Monitoring of Steroids

Technologies and devices for continuous monitoring of cortisol (or hydrocortisone) levels are increasingly important for use in a wide range of applications starting from endocrinology to military to sports, as it regulates many important pathophysiological functions [1,2]. Cortisol is a steroid hormone produced in adrenal glands, released in bio-fluids, in response to events and circumstances such as fear, stress, and exercising. Thus, the measurement of cortisol in the bio-fluids is an important tool for use in clinical diagnostics and in monitoring stress levels during stress-intensive activities. Conventional devices, such as cortisol flow immunoassays (FIA)[3], salivary cortisol assay kits[4], are available in the market and are capable of measuring cortisol levels in collected saliva/serum samples. However, such assay kits still suffer from tedious lab processing and the time associated therewith. Currently, affinity based biosensor prototypes involving antibodies and aptamers as recognition element to capture cortisol have been widely reported by researchers. However, there are many challenges associated with the affinity based assays that restricts commercialization. So there is a real need for developing catalytic sensor that would provide continuous monitoring of cortisol levels at clinical setting. Porphyrins and their derivatives are highly conjugated heterocyclic macrocycle organic compounds. The macrocyclic structure of porphyrin can conjugate with many metal elements to form stable metalloporphyrins which has remarkable electrocatalytic, photocatalytic, and biochemical properties. Metallophorphyrins are known as bioinspired catalyst since they are the actual catalytic active site (prosthetic group) of important class of proteins and enzymes. Metalloporphyrins based catalytic sensors have been reported for the detection of sulphur ions[5], nitric oxide[6], nitrite[7] and have not been used for detecting cortisol. Cortisol ((11β)-11,17,21-Trihydroxypregn-4-ene-3,20-dione) is an unsaturated ketosteroid and containing keto group at 3rd and 20thposition. The reduction reaction of keto groups of the cortisol to hydroxyl group catalyzed by metalloporphyrins is utilized here for the direct detection of cortisol. The proposed technology involves the cladding of the catalytic biosensor with conductive textile/fabric to wick and transfer the sweat to the sensing surface to enable continuous monitoring of cortisol. The current response of the sensor was found to a strong linear function of cortisol concentrations in the range 50 pM-100 nM. Detection limit is found to be as low as 10 pM. The schematic representation of working principle of catalytic cortisol sensor is represented in scheme 1. Scheme 1. Electrochemical pathway of reduction of cortisol at electrode for continuous monitoring.

MS and GC–MS studies on phthalocyanine monomers

AbstractPhthalocyanines are a class of macrocyclic organic compounds known for their high tinctorial properties, thermal stability, chemical inertness, catalytic activity, and photoconductivity. A mass spectral study on metal phthalocyanines presented many difficulties because of their excellent thermal stability. The present work deals with MS and GC–MS studies of phthalocyanine, copper, and nickel phthalocyanine monomers at various temperatures. Tentative mechanism for the modes of fragmentation is proposed.