Tailored Covalent Organic Framework Platform: From Multistimuli, Targeted Dual Drug Delivery by Architecturally Engineering to Enhance Photothermal Tumor Therapy.

Engineering bulk covalent organic frameworks (COFs) to access specific morphological structures holds paramount significance in boosting their functions in cancer treatment; nevertheless, scant effort has been dedicated to exploring this realm. Herein, silica core-shell templates and multifunctional COF-based reticulated hollow nanospheres (HCOFs) are novelly designed as a versatile nanoplatform to investigate the simultaneous effect of dual-drug chemotherapy and photothermal ablation. Taking advantage of the distinct structural properties of the template, the resulting two-dimensional (2D) HCOF, featuring large internal voids and a peripheral interconnected mesoporous shell, presents intriguing benefits over its bulk counterparts for cancer treatment, including a well-defined morphology, an outstanding drug loading capability (99.6%) attributed to its ultrahigh surface area (2087 m2/g), great crystallinity, improved tumor accumulation, and an adjustable drug release profile. After being loaded with hydrophilic doxorubicin with a remarkable loading capacity, the obtained drug-loaded HCOFs were coated with gold nanoparticles (Au NPs) to confer them with three properties, including pore entrance blockage, active-targeting capability, and improved biocompatibility via secondary modification, besides high near infrared (NIR) absorption for efficient photothermal hyperthermia cancer suppression. The resultant structure was functionalized with mono-6-thio-ß-cyclodextrin (ß-CD) as a second pocket to load docetaxel as the hydrophobic anticancer agent (combination index = 0.33). The dual-drug-loaded HCOF displayed both pH- and near-infrared-responsive on-demand drug release. In vitro and in vivo evaluations unveiled the prominent synergistic performance of coloaded HCOF in cancer elimination upon NIR light irradiation. This work opens up a new avenue for exciting applications of structurally engineered HCOFs as hydrophobic/hydrophilic drug carriers as well as multimodal treatment agents.

Coumarin derivative-functionalized nanoporous silica as an on-off fluorescent sensor for detecting Fe3+ and Hg2+ ions: a circuit logic gate.

A highly efficient fluorescent sensor (S-DAC) was easily created by functionalizing the SBA-15 surface with N-(2-Aminoethyl)-3-Aminopropyltrimethoxysilane followed by the covalent attachment of 7-diethylamino 3-acetyl coumarin (DAC). This chemosensor (S-DAC) demonstrates selective and sensitive recognition of Fe3+ and Hg2+ in water-based solutions, with detection limits of 0.28 × 10-9 M and 0.2 × 10-9 M for Hg2+ and Fe3+, respectively. The sensor's fluorescence characteristics were examined in the presence of various metal ions, revealing a decrease in fluorescence intensity upon adding Fe3+ or Hg2+ ions at an emission wavelength of 400 nm. This sensor was also able to detect ferric and mercury ions in spinach and tuna fish. The quenching mechanism of S-DAC was investigated using UV-vis spectroscopy, which confirmed a static-type mechanism for fluorescence quenching. Moreovre, the decrease in fluorescence intensity caused by mercury and ferric ions can be reversed using trisodium citrate dihydrate and EDTA as masking agents, respectively. As a result, a circuit logic gate was designed using Hg2+, Fe3+, trisodium citrate dihydrate, and EDTA as inputs and the quenched fluorescence emission as the output.

Chitosan-derived mesoporous N-doped carbon catalyst embedded with NiO for highly selective benzyl alcohol oxidation.

MOF-derived heteroatom-doped mesoporous carbons have gained the significant consideration in heterogenous catalytic reactions because of their multipurpose features. Especially, the high Specific Surface Area (SSA) of these materials provides abundant activated sites for the catalytic reactions, while the mesoporous structure allows for the effective mass transfer, enhancing the overall capability of the catalytic process. Herein, the efficient NiO/CN-T (T referred to the pyrolysis temperature) was prepared by facile pyrolysis of MOF/CS composite (Ni-MOF (74), Chitosan) in the presence of excess amount of starch as the carbon precursor. The NiO/CN-T as heterogenous catalyst has desired SSA varied from 1094 to 491 m2.g-1. The optimized catalyst (NiO/CN-600) possesses the superior catalytic activity toward the oxidation of the BnOHs due to its high SSA (1094 m2.g-1), which can notably rectify the mass transfer proficiency. Additionally, the NiO/CN-600 heterogenous catalyst also represents the acceptable chemical stability. So, it was demonstrated that such an innovative strategy can provide several versatile tunability insights for the preparation of MOF/biopolymer-derived heterogenous catalysts.

Fumed-Si-Pr-PNS as a Photoluminescence sensor for the Detection of Hg2+ in Aqueous Media.

Fumed silica was functionalized by piperazine followed by the reaction with 2- naphthalenesulfonyl chloride to prepare Fumed-Si-Pr-Piperazine-Naphthalenesulfonyl chloride (Fumed-Si-Pr-PNS), which was characterized to demonstrate the effective attachment on the surface of fumed silica. The optical sensing ability of Fumed-Si-Pr-PNS was studied via diverse metal ions in H2O solution by photoluminescence spectroscopy. The results showed that Fumed-Si-Pr-PNS detected selectively Hg2+ ions. The prepared sensor showed almost high absorption at different pH for Hg ion. After drawing various diagrams, The detection limits were calculated at about 12.45 × 10-6 M for Hg2+.

ZnO/black phosphorus/C3N4 composite: An effective photocatalyst for Cr (VI) reduction and degradation of rhodamine B.

The utilization of photocatalysts offers a promising approach for the removal of Cr (VI) and rhodamine dyes. Through the generation of reactive species and subsequent degradation reactions, photocatalysis provides an efficient and environmentally friendly method for the remediation of wastewater. In this study, we have synthesized an n-p-n heterojunction of carbon nitride (C3N4), zinc oxide (ZnO), and black phosphorus (BP) through the sonication-stirring method. The photocatalytic ability of this composite was examined for the decomposition rhodamine B (RhB) and detoxification of hexavalent chromium ion (up to 97% during 80 min) under Xenon irradiation. The results of trapper experiments indicated that the active species were hydroxyl radical (˙OH), electron (e-), and superoxide anion radical (˙O2-). Based on the obtained potential of the lowest unoccupied molecular orbitals (LUMO) and the highest occupied molecular orbital (HOMO) for the mentioned semiconductors, through Mutt-Schottky results, the double Z-scheme mechanism was proposed for the studied process. The electrochemical impedance spectroscopy data exhibited good charge transfer for the evaluated composite versus the pure compounds. The impressive separation of holes and electrons along with the low recombination were confirmed by the responses of photocurrent and quenching the photoluminescence (pl) intensity for the composite, respectively. The current density of the composite recorded 66.6%, 87.3%, and 92% higher than those of BP, C3N4, and ZnO, indicating an excellent electron-hole separation for the ternary composite compared to the pure semiconductors. Diffuse reflectance spectra (DRS) data revealed 2.9, 3.17, 1.15, and 2.63 eV as the band gap values for C3N4, ZnO, BP, and composite. The rate constant of the new composite to remove RhB and reduce hexavalent chromium were about 4.79 and 2.64 times higher than that of C3N4, respectively.

Black Phosphorus-based Photocatalysts: Synthesis, Properties, and Applications.

Photocatalysis is considered as an eco-friendly and sustainable strategy, since it uses abundant light for the advancement of the reaction, which is freely accessible and is devoid of environmental pollution. During the last decades, (nano)photocatalysts have gained broad industrial applications in terms of purification and detoxification of water as well as production of green fuels and hydrogen gas due to their special attributes. The degradation or remediation of toxic and hazardous compounds from the environment or changing them into non-toxic entities is a significant endeavor and necessary for the safety of humans, animals, and the environment. Black phosphorus (BP), a two-dimensional single-element material, has a marvelous structure, tunable bandgap, changeable morphology from bulk to nanosheet/quantum dot, and unique physicochemical properties, which makes it attractive material for photocatalytic applications, especially for sustainable development purposes. Since it can serve as a photocatalyst with or without coupling with other semiconductors, various aspects for multidimensional exploitation of BP are deliberated including their preparation via solvothermal, ball milling, calcination, and sonication methods to obtain BP from red phosphorus. The techniques for improving the photocatalytic and stability of BP-based composites are discussed along with their multifaceted applications for environmental remediation, pollution degradation, water splitting, N2 fixation, CO2 reduction, bacterial disinfection, H2 generation, and photodynamic therapy. Herein, most recent advancements pertaining to the photocatalytic applications of BP-based photocatalyst are cogitated, with a focus on their synthesis and properties as well as crucial challenges and future perspectives.

Enhanced photocatalytic activity of modified black phosphorus-incorporated PANi/PAN nanofibers.

Enhancement of the photocatalytic activity of black phosphorus (BP) is a highly challenging proposition. The fabrication of electrospun composite nanofibers (NFs) through the incorporation of modified BP nanosheets (BPNs) into conductive polymeric NFs has been recently introduced as a newer strategy not only to enhance the photocatalytic activity of BPNs but also to overcome their drawbacks including ambient instability, aggregation, and hard recycling, which exist in their nanoscale powdered forms. The proposed composite NFs were prepared through the incorporation of silver (Ag)-modified BPNs, gold (Au)-modified BPNs, and graphene oxide (GO)-modified BPNs into polyaniline/polyacrylonitrile (PANi/PAN) NFs by an electrospinning process. The successful preparation of the modified BPNs and electrospun NFs was confirmed by the characterization techniques of Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible (UV-vis), powder X-ray diffraction (PXRD), and Raman spectroscopy. The pure PANi/PAN NFs exhibited high thermal stability with a main weight loss of ∼23% for the temperature range of 390-500 °C, and the thermal stability of NFs was enhanced after their incorporation with the modified BPNs. The BPNs@GO-incorporated PANi/PAN NFs indicated improved mechanical properties compared to the pure PANi/PAN NFs with tensile strength (TS) of 1.83 MPa and elongation at break (EAB) of 24.91%. The wettability of the composite NFs was measured in the range of 35-36°, which exhibited their good hydrophilicity. The photodegradation performance was found in the sequence of BPNs@GO > BPNs@Au > BPNs@Ag > bulk BP ∼BPNs > red phosphorus (RP) for methyl orange (MO) and in the sequence of BPNs@GO > BPNs@Ag > BPNs@Au > bulk BP > BPNs > RP for methylene blue (MB), accordingly. The composite NFs degraded the MO and MB dyes more efficiently relative to the modified BPNs and pure PANi/PAN NFs.

Recent advances in covalent organic frameworks (COFs) for wound healing and antimicrobial applications.

Covalent organic frameworks (COFs) are crystal-like organic structures such as cartography buildings prepared from appropriately pre-designed construction block precursors. Moreover, after the expansion of the first COF in 2005, numerous researchers have been developing different materials for versatile applications such as sensing/imaging, cancer theranostics, drug delivery, tissue engineering, wound healing, and antimicrobials. COFs have harmonious pore size, enduring porosity, thermal stability, and low density. In addition, a wide variety of functional groups could be implanted during their construction to provide desired constituents, including antibodies and enzymes. The reticular organic frameworks comprising porous hybrid materials connected via a covalent bond have been studied for improving wound healing and dressing applications due to their long-standing antibacterial properties. Several COF-based systems have been planned for controlled drug delivery with wound healing purposes, targeting drugs to efficiently inhibit the growth of pathogenic microorganisms at the wound spot. In addition, COFs can be deployed for combinational therapy using photodynamic and photothermal antibacterial therapy along with drug delivery for healing chronic wounds and bacterial infections. Herein, the most recent advancements pertaining to the applications of COF-based systems against bacterial infections and for wound healing are considered, concentrating on challenges and future guidelines.

MOF-based composites as photoluminescence sensing platforms for pesticides: Applications and mechanisms.

Metal-organic frameworks (MOFs) have recently garnered considerable attention among reticular compounds due to their unique physicochemical properties and applications in sensing toxic compounds. On the other hand, fluorometric sensing has been widely studied for food safety and environmental protection among the various sensing methods. Thus, designing MOF-based fluorescence sensors for specific detection of hazardous compounds, especially pesticides, are incessantly needed to keep up with the continuous demands for monitoring these environmental pollution. Herein, recent MOF-based platforms for pesticide fluorescence detection are deliberated owing to sensors' emission origins and in terms of their structural properties. The influences of different guest incorporation in MOFs on pesticide fluorescence detection are summarized, and the future developments of novel MOF composites such as polyoxometalate@MOFs (POMOF), carbon quantum dots@MOFs (CDs@MOF), and organic dye@MOF are prospected for fluorescence sensing of assorted pesticides with a focus on mechanistic insights of specific detection techniques in food safety and environmental protection.

Electrospun composite nanofibers as novel high-performance and visible-light photocatalysts for removal of environmental pollutants: A review.

Environmental pollution caused by industries and human manipulations is coming a serious global challenge. On the other hand, the world is facing an energy crisis caused by population growth. Designing solar-driven photocatalysts which are inspired by the photosynthesis of plant leaves is a fantastic solution to use solar energy as green, available, and unlimited energy containing ∼50% visible light for the removal of environmental pollutants. The polymeric and non-polymeric-based electrospun composite nanofibers (NFs) are as innovative photocatalytic candidates which increase photocatalytic activity and transition from UV light to visible light and overcome the aggregation, photocorrosion, toxicity, and hard recycling and separation of the nanosized powder form of photocatalysts. The composite NFs are fabricated easily by either embedding the photocatalytic agents into the NFs during electrospinning or via their decorating on the surface of NFs post-electrospinning. Polyacrylonitrile-based, tungsten trioxide-based, zinc oxide-based, and titanium dioxide-based composite NFs were revealed as the most reported composite NFs. All the lately investigated electrospun composite NFs indicated long-term stability, high photocatalytic efficiency (∼> 80%) within a short time of light radiation (10-430 min), and high stability after several cycles of use. They were applied in various applications including degradation of dyes/antibiotics, water splitting, wastewater treatment, antibacterial usage, etc. The photogenerated species especially holes, O2∙-, and .OH were mostly responsible for the photocatalytic mechanism and pathway. The electrospun composite NFs have the potential to use in large-scale productions in condition that their thickness and recycling conditions are optimized, and their toxicity and detaching are resolved.

Ultrasound-assisted synthesis of europium doped BPO4 nanoparticles; a new approach for Zn2+ (aq) detection.

In this work, europium ion was doped into boron phosphate nanoparticles (BPO4) using an ultrasonic method followed by the calcination process. The nanoparticles were characterized by various techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy, transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, and scanning electron microscopy (SEM). Doping of europium ion into the BPO4 host crystal was proved by cell volume calculation from XRD patterns, the shift in Raman spectra, and photoluminescence properties. In addition, the europium doped boron phosphate (BPE) as a fluorescence sensor for the quantification of Zn2+ cation was studied. The obtained results showed the enhancement and shift of the photoluminescence peak from 292 to 340 nm. The sensor's selectivity toward this ion was verified in the presence of a variety of common interfering cations. Surprisingly, BPE revealed excellent selectivity and sensitivity towards Zn2+ in the presence of Pb2+, Na+, Fe2+, Al3+, Ca2+, Mg2+, Cu2+, Co2+, Ni2+, Mn2+, Cd2+, Hg2+, Ba2+ and Fe3+ cations. The fluorescence response was linearly proportional to the Zn2+concentration. After the addition of trace amounts of Zn2+ ions into the aqueous solution, a significant enhancement of fluorescence emission occurred with the detection limit of 0.3 µM.

Spiroindeno-pyridineindoles (SIPIs) as new visible colorimetric pH indicators.

Some new, highly selective, and sensitive colorimetric pH indicators, spiro[4H-indeno-[1,2-b]pyridine-4,3'-[3H]indoles] (SIPIs) in aqueous solution were developed. SIPIs were synthesized via a one-pot four-component condensation of isatin derivatives, ß-diketones 1,3-indandione, and ammonium acetate using FSi-PrNH-BuSO3H as a nanocatalyst in EtOH. According to the experimental evaluations, it was found that SIPI derivatives are pH indicators for naked-eye detection of OH- ion with intense color changes from orange to purple in the pH range of 10.3-12.

Silica-coated modified magnetic nanoparticles (Fe3O4@SiO2@(BuSO3H)3) as an efficient adsorbent for Pd2+ removal.

It is crucial to fabricate cost-effective and efficient strategies for monitoring and eliminating hazardous metals in the water supplies. Among the many techniques, adsorption is one of the most powerful and facile ways for eliminating pollutants from effluents. It is also crucial to engineering high-performance low-cost adsorbents. In this regard, herein, Fe3O4@SiO2@(BuSO3H)3 as a modified core-shell magnetic silica nanoparticle embodies good selectivity to extract toxic metal ions from aquatic media. The present work investigated the removal performance of the magnetic adsorbent towards Pd2+ cation amongst the other heavy metal ions including Co2+, Pb2+, Hg2+, Cd2+, Cu2+, Zn2+ in aqueous solution. The flame atomic absorption spectrometry (FAAS) was utilized to assess the removal efficiency of the adsorbent. Several experimental parameters including elution condition, initial Pd(II) concentration, adsorbent dosage, initial pH of the solution, and contact time were explored to achieve the optimal conditions. The data of adsorption were very well with the Langmuir isotherm model, according to the adsorption isotherm mechanism experiments. In conclusion, this study lays the way for the development of novel magnetic adsorbents with high removal efficiencies for the removal of toxic metal ions from aqueous environment.

Recent advances in the application of magnetic bio-polymers as catalysts in multicomponent reactions.

Magnetic nanoparticles have attracted significant attention due to their high surface area and superparamagnetic properties. Bio-polymers composed of polysaccharides including alginate, cellulose, glucose, dextrin, chitosan, and starch can be immobilized on magnetic nanoparticles. Bio-polymers can be obtained from natural sources, such as plants, tunicates, algae, and bacteria. Bio-polymers obtained from natural sources have attracted attention due to their various properties including efficient functional groups, non-toxicity, low cost, availability, and biocompatibility. According to the targets of "green chemistry", the application of bio-polymers is effective in reducing pollution. Furthermore, they are excellent agents for the functionalization of magnetic nanoparticles to yield nanomagnetic bio-polymers, which can be applied as recoverable and eco-friendly catalysts in multicomponent reactions.

The Molecular Diversity of 1H-Indole-3-Carbaldehyde Derivatives and Their Role in Multicomponent Reactions.

1H-Indole-3-carbaldehyde and related members of the indole family are ideal precursors for the synthesis of active molecules. 1H-Indole-3-carbaldehyde and its derivatives are essential and efficient chemical precursors for generating biologically active structures. Multicomponent reactions (MCRs) offer access to complex molecules. This review highlights the recent applications of 1H-indole-3-carbaldehyde in such inherently sustainable multicomponent reactions from the period, 2014 to 2021 and provides an overview of the field that awaits further exploitation in the assembly of pharmaceutically interesting scaffolds.

Molecular docking and optical sensor studies based on 2,4-diamino pyrimidine-5-carbonitriles for detection of Hg2.

An organic chemical sensor based on pyrimidine was successfully produced through the green reaction between aromatic aldehyde, malononitrile, and guanidine carbonate using SBA-Pr-SO3H. This fluorescence intensity of chemosensor (2,4-diamino-6-(phenyl)pyrimidine-5-carbonitrile) decreases by the addition of Hg2+ and its detection limit is about 14.89 × 10-5 M, in fact, through the green synthesis, the ligand was yielded to detect Hg2+ and the importance of ligand was considered in docking studies. The molecular docking of 2,4-diamino-6-(phenyl)pyrimidine-5-carbonitrile compound has been done with the protein selective estrogen receptor 5ACC complexed with (Azd9496), Human Anaplastic Lymphoma Kinase Pdb; 2xp2 complex with crizotinib (PF-02341066) and human wee1 kinase Pdb; 5vc3 complexed with bosutinib. The ligands 2,4-diamino-6-(phenyl)pyrimidine-5-carbonitrile generate very good docking results with the protein Pdb; 2xp2, which is responsible for effective tumor growth inhibition.

A novel fluorescence sensor based on a tripodal carboxylic acid for detection and measurement of Cu2+ in tomato: Experimental and computational studies.

A tripod organic compound, (4,4',4''-[1,3,5-Triazine-2,4,6-triyltris(oxy)] tribenzoic acid, TCPT), with donor triazine core and multiple fluorophore carboxylic motives, was prepared as an efficient ligand with high emission properties. The TCPT fluorescence emission properties as a chemical sensor were studied (λex = 370 nm) upon the addition of an appropriately diverse set of metal cations. The obtained results revealed the highly selective and efficient role of Cu2+ in quenching of TCPT, even with relevant interfering metal ions. The emission of TCPT was independent of the pH. The interaction of the sensor with Cu2+ and followed by absorption spectra and linear trend of the Stern-Volmer diagram, suggested a static quenching process. The density functional theory calculations were carried out to explore the identity of the electronic transition levels, HOMO-LUMO, and bandgap energies of TCPT. The linear range 1.00 × 10-7-1.00 × 10-6 M was obtained by fluorescence titration of a TCPT solution with Cu2+ ions at optimum conditions. The detection limit was calculated as 5.45 × 10-8 M from the established calibration of titration data. The effect of various ions was studied, and there was no significant interference from the studied metal ions. For the real sample analysis, trace levels of Cu2+ ions were successfully determined in the tomato.

Electrospun Ag-decorated reduced GO-graft-chitosan composite nanofibers with visible light photocatalytic activity for antibacterial performance.

The treatment of water contaminated by bacteria is becoming a necessity. The nanomaterials possessing both intrinsic antibacterial properties and photocatalytic activity are excellent candidates for water disinfection. The powdered form of nanomaterials can be aggregated while embedding the nanomaterials into the NFs can overcome the limitation and enhance the photocatalytic activity and transition from UV-light to visiblelight. Here, graphene oxide (GO) was synthesized, grafted to chitosan, and decorated with silver nanoparticles (Ag NPs) to produce Ag-decorated reduced GO-graft-Chitosan (AGC) NPs. The blends of polyacrylonitrile (PAN) and AGC NPs were prepared in various concentrations of 0.5 wt%, 1.0 wt%, 5.0 wt%, and 10.0 wt% and used to fabricate the electrospun composite NFs. FTIR/ATR, UV-Vis, Raman, XRD, and SEM/EDAX analyses confirmed the successful preparation of the NPs and NFs. The cytotoxicity and antibacterial activity of the composite NFs were received in the order of composite NFs 10.0 wt%˃ 5.0 wt%˃ 1.0 wt%˃ 0.5 wt% in both conditions with/without light irradiation. Their cytotoxicity and antibacterial activity were more under light irradiation compared to the dark. The composite NFs (5.0 wt%) were distinguished as the optimum NFs with cell viability of 80% within 24 h and 60% within 48 h on L929 cells and inhibition zone diameter (IZD) of 12 mm for E. coli and 13 mm for S. aureus after 24 h under the light irradiation. The optimum composite NFs showed thermal stability up to 180 °C and tensile strength of 1.11 MPa with 21.71% elongation at break.

Recent advances on the synthesis of natural pyrrolizidine alkaloids: alexine, and its stereoisomers.

Natural products have attracted the interest of the scientific community due to their importance and application. Alexine is a naturally polyhydroxylated pyrrolizidine alkaloid that is broadly found in plant sources and isolated from Alexa leiopetala. The biological properties such as glycosidase inhibitors, anti-virus, and anti-HIV activities, makes it interesting target for synthetical studies. This review reports different approaches and methodologies to the synthesis of alexine, and its stereoisomers as the target compounds in numerous studies.

Pomegranate Punica granatum peel waste as a naked-eye natural colorimetric sensor for the detection and determination of Fe+3 and I- ions in water.

The utilization of renewable and abundant agricultural waste such as Pomegranate (Punica granatum L.) peel extract has been developed wherein a simple extraction of dried peel in water offered a natural sensor; ensuing yellowish solution comprising phenolic compounds reacted explicitly to detect Fe+3 and I- solutions by naked-eye. The UV-Vis absorption spectrum of the resulting extracted mixture was drastically changed toward the longer wavelengths only after the addition of the Fe3+ and I- while there was no discernible spectral change due to the addition of a broad range of other common cations and anions. In the case of Fe3+ and I-, the transformation can be followed by the naked eye in the concentration range of 5 × 10-4 M and 1 × 10-2 M, respectively. An acceptable and reasonable detection with 47.05426 µM efficiency was attained in comparison to other Fe3+ indicators such as ferroin.