Phosphonate Groups Research Articles

A Phosphonic Functionalized Biopolymer for the Sorption of Lanthanum (III) and Application in the Recovery of Rare Earth Elements

Phosphonic acid functionalization of gellan gum and chitosan biopolymers was successfully performed. In the first step, the sorption was investigated using La(III) ions before testing for the recovery of rare earth elements (REEs) from pretreated industrial acidic leachate. The sorbent was characterized by Fourier-transform infrared (FTIR), scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET), and pH of zero charge (pHPZC) determination. FTIR and EDX results show efficient grafting of phosphoryl groups. The sorption was determined for the crude materials before functionalization (PGEG) and after phosphorylation (TBP-PGEG). More efficient sorption was seen for phosphorylated sorbent than for the crude composite. The sorption capacity is 0.226 mmol La g−1 for the PGEG while the value is 0.78 mmol La g−1 for the TBP-PGEG. We infer that phosphonate groups participate in the sorption. The most effective sorption is at pH = 4. The kinetic behavior was described using pseudo first-order equations (PFORE), pseudo second-order equations (PSORE), and resistance to intraparticle diffusion (RIDE). The sorption isotherms can be better represented by Langmuir and Sips equations than by the Freundlich equation. The sorbent shows high stability performance during reuse cycles with a limit on the decrease in the sorption performances and stability in the desorption performances. We have thus developed a good tool for the recovery of REEs with a selectivity higher than that of the non-functionalized components.

Remediation of heavy-metal-contaminated soil with two organic acids: Washing efficiency, recovery performance, and benefit analysis

There remains a need to develop efficient and recoverable washing reagents to repair heavy metal-contaminated soil. However, the past study of recovery only considered conventional chelating agents, hindering the sustainable development of new reagents. In this study, two new-reagents, organic phosphonic acid (DTPMPA) and polycarboxylic acid (AA/AMPS/HPA), simultaneously investigated their ability to remove heavy metal and recover by electrochemical to improve reagent sustainability. Results indicated that the metal removals were influenced by the washing solution concentrations, pH, and contact time. The maximum removal by DTPMPA was 72% Cd and 33% Zn, were higher than those of AA/AMPS/HPA (concentration, 5%; pH, 3.0; and contact time, 120 min). The strong chelation of the phosphonic acid group of DTPMPA binds more metal ions. Characterization results demonstrated that both reagents were successfully recovered using electrochemical methods. While AA/AMPS/HPA had a better recovery performance because of electrostatic adsorption interactions with the metal ions, the rewashing ability of Cd and Zn was 88% and 64% of the fresh solution. Moreover, in benefit analysis, AA/AMPS/HPA showed better circular economy and long-term sustainability properties. Therefore, AA/AMPS/HPA is a feasible remediation reagents of the heavy-metal-contaminated soil with both efficiency and sustainability. The development of reagent takes into account efficiency and reuseable simultaneously, showing great economic benefits.

Synthesis, characterization, photo-polymerization, hydrolytic stability, and etching behavior of new self-etch adhesive monomers

Considering the poor hydrolytic stability of the most methacrylate-based functional monomers of self-etch dental adhesives in acidic and aqueous conditions, in this study allyl-based photo-polymerizable self-etch monomers was synthesized in order to improve the hydrolytic stability.The new self-etch monomers based on phosphonic acid functional groups were synthesized through a two-step procedure. First, phosphoric anhydride, poly-phosphoric acid, and polyethylene glycol were reacted to produce phosphate ester precursor (P-PEG-P). Next, allyl 2, 3-epoxypropyl ether was reacted with P-PEG-P to synthesize allyl self-etch monomer. Glycidyl methacrylate was also reacted with P-PEG-P to synthesize a methacrylate self-etch analogue monomer. The monomers were characterized using FTIR and 1H-NMR spectroscopy. The viscosities of monomers were measured using a rheometer. The degree photopolymerization conversion of monomers was measured using FTIR spectroscopy. The pH assay was performed by a digital pH-meter. The etching behavior of the monomers on human teeth was studied using scanning electron microscopy (SEM). Thermo-gravimetric analysis (TGA) was performed to evaluate the possible interaction of the monomers with tricalcium phosphate (TCP). The solubility of synthesized monomers was examined in ethanol, acetone, and water. The hydrolytic stability of cured resins in artificial saliva during 4 months was also surveyed.The synthesis of new self-etching monomers was successfully confirmed by spectroscopy analyses. The results represented appropriate viscosity of self-etching monomers around 1 (Pa s). The resin containing methacrylate monomer exhibited its degree of conversion is more than that of allyl monomer (p < 0.05). The allyl and methacrylate self-etch monomers exhibited pH values of 1.2 and 1.3, respectively. SEM micrograph verified that the synthesized monomers were able to suitable etching of the enamel human premolar teeth. The data obtained from TGA tests revealed that thermal stability of (TCP) containing monomers is enhanced. Also, the monomers exhibited an excellent solubility in polar solvents, but when they are mixed with TCP, they are not, anymore, dissolved in these solvents. Furthermore, the allyl monomer showed higher hydrolytic stability than the methacrylate monomer.The new photo-polymerizable acidic monomer based on allyl functionality showed enhanced hydrolytic stability compared to methacrylate-based monomer. It may be considered as a promising monomer for self-etch dental adhesives.

Tailoring Multifunctional Self‐Assembled Hole Transporting Molecules for Highly Efficient and Stable Inverted Perovskite Solar Cells

AbstractThe self‐assembled hole transporting molecules (SAHTMs) bearing anchoring groups have been established as the hole transporting layers (HTLs) for highly efficient p–i–n perovskite solar cells (PSCs), yet their stability and engineering at the molecular level remain challenging. A topological design of highly anisotropic aligned SAHTM‐based HTLs for operationally stable PSCs that exhibit exceptional solar‐to‐electric power conversion efficiencies (PCEs) is demonstrated. The judiciously designed multifunctional self‐assembled molecules comprise the donor–acceptor subunit for hole transporting and the phosphonic acid group for anchoring, realizing face‐on π‐stacking parallel to the transparent conductive oxide substrate. The high affinity of SAHTMs to the multi‐crystalline perovskite thin film benefits passivating the perovskite buried interface, strengthening interfacial contact while facilitating interfacial hole transfer. Consequently, highly efficient p–i–n PSC devices are obtained with a champion PCE of 23.24% and outstanding operational stability toward various environmental factors including long‐term full sunlight soaking at evaluated temperatures. Perovskite solar modules with a champion efficiency approaching 20% are also fabricated for an active device area above 17 cm2.

Saturation magnetisation as an indicator of the disintegration of barium hexaferrite nanoplatelets during the surface functionalisation

Barium hexaferrite nanoplatelets (BHF NPLs) are permanent nanomagnets with the magnetic easy axis aligned perpendicular to their basal plane. By combining this specific property with optimised surface chemistry, novel functional materials were developed, e.g., ferromagnetic ferrofluids and porous nanomagnets. We compared the interaction of chemically different phosphonic acids, hydrophobic and hydrophilic with 1–4 phosphonic groups, with BHF NPLs. A decrease in the saturation magnetisation after functionalising the BHF NPLs was correlated with the mass fraction of the nonmagnetic coating, whereas the saturation magnetisation of the NPLs coated with a tetraphosphonic acid at 80 °C was significantly lower than expected. We showed that such a substantial decrease in the saturation magnetisation originates from the disintegration of BHF NPLs, which was observed with atomic-resolution scanning transmission electron microscopy and confirmed by a computational study based on state-of-the-art first-principles calculations. Fe K-edge XANES (X-ray absorption near-edge structure) and EXAFS (Extended X-ray absorption fine structure) combined with Fourier-transformed infrared (FTIR) spectroscopy confirmed the formation of an Fe–phosphonate complex on the partly decomposed NPLs. Comparing our results with other functionalised magnetic nanoparticles confirmed that saturation magnetisation can be exploited to identify the disintegration of magnetic nanoparticles when insoluble disintegration products are formed.

Исследование зависимости фармакокинетических и дозиметрических характеристик меченных Re-188 фосфоновых кислот от их структуры в организме крыс на основе камерного моделирования

Phosphonic acids labeled with radionuclide Re-188 are the most promising radiopharmaceuticals for radionuclide therapy of bone metastases. The aim of the work is to develop a compartment mathematical model of the kinetics of Re-188-labeled phosphonic acids in the body of intact rats and calculate on its basis the pharmacokinetic and dosimetric characteristics of these radiopharmaceuticals with different chemical structures. The objects of the study were four radiopharmaceuticals containing from two to five phosphonic groups. To identify the model parameters and calculate the characteristics, quantitative data on the bio-distribution of 188Re-labeled phosphonic acids in the body of intact rats were used. A compartment model of kinetics has been developed and two approaches to the identification of its transport constants have been proposed – through the residual functional and using approximation by monoexponential functions. According to pharmacokinetic modeling, all studied radiopharmaceuticals selectively accumulate in bone tissues, and the chemical structure of phosphonic acids affects their accumulation and excretion. According to the level of accumulation of activity in the skeleton, the structures of radiopharmaceuticals can be arranged in descending order: five phosphonic groups &gt; two &gt; four. At the same time, the radiopharmaceutical with two phosphonic groups is removed from the bone tissues most slowly, which is its advantage. The rate of removal of radiopharmaceuticals from the blood and other organs is on average three times higher than from bone tissue. The elimination of radioactivity from the body occurs mainly through renal clearance. The highest values of absorbed doses are formed in the bone tissues (thighs, ribs, skull, spine) and the organ of excretion – the kidneys. At the same time, the maximum values of absorbed doses in bone tissues were obtained for radiopharmaceuticals with five and two phosphonic groups, which together with their pharmacokinetic properties allows them to be considered as promising osteotropic radiopharmaceuticals for the treatment of bone metastases.

Self-driven near infrared photoelectric detector based on C&lt;sub&gt;14&lt;/sub&gt;H&lt;sub&gt;31&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;P-Ti&lt;sub&gt;3&lt;/sub&gt;C&lt;sub&gt;2&lt;/sub&gt;/Au Schottky junction

Ti&lt;sub&gt;3&lt;/sub&gt;C&lt;sub&gt;2&lt;/sub&gt;T&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt;, as one of new two-dimensional materials MXene, has abundant surface functional groups (—OH, —F, and —O, etc.) and can exhibit semiconductor properties through further surface functionalization. In addition, it has excellent absorption capabilities for both infrared and visible light. Currently, there is limited research on applying the semiconductor properties of Ti&lt;sub&gt;3&lt;/sub&gt;C&lt;sub&gt;2&lt;/sub&gt;T&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt; to infrared photodetectors. In this study, a self-driven near-infrared photodetector based on a C&lt;sub&gt;14&lt;/sub&gt;H&lt;sub&gt;31&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;P-Ti&lt;sub&gt;3&lt;/sub&gt;C&lt;sub&gt;2&lt;/sub&gt;/Au Schottky junction is developed. The modified C&lt;sub&gt;14&lt;/sub&gt;H&lt;sub&gt;31&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;P-Ti&lt;sub&gt;3&lt;/sub&gt;C&lt;sub&gt;2&lt;/sub&gt; two-dimensional semiconductor is prepared by a simple solution method, in which the phosphonic acid group reacts with the hydroxyl group on the Ti&lt;sub&gt;3&lt;/sub&gt;C&lt;sub&gt;2&lt;/sub&gt;T&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt; surface. The C&lt;sub&gt;14&lt;/sub&gt;H&lt;sub&gt;31&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;P-Ti&lt;sub&gt;3&lt;/sub&gt;C&lt;sub&gt;2&lt;/sub&gt;/Au photodetector is constructed by using a drop-coating method at room temperature. The observation of an S-shaped curve in the &lt;i&gt;I&lt;/i&gt;-&lt;i&gt;V&lt;/i&gt; characteristics indicates the formation of a Schottky junction between C&lt;sub&gt;14&lt;/sub&gt;H&lt;sub&gt;31&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;P-Ti&lt;sub&gt;3&lt;/sub&gt;C&lt;sub&gt;2&lt;/sub&gt; nanosheets and the Au electrode. The device exhibits good detection performance in the near-infrared band (808–1342 nm), with a maximum responsivity of 0.28 A/W, a detectivity of 4.3×10&lt;sup&gt;7&lt;/sup&gt; Jones and an external quantum efficiency (EQE) of 32.75% under 1064 nm infrared light illumination. The &lt;i&gt;I&lt;/i&gt;&lt;sub&gt;on&lt;/sub&gt;/&lt;i&gt;I&lt;/i&gt;&lt;sub&gt;off&lt;/sub&gt; ratio is 10.4, which is about 7.3 times higher than that under 1342 nm light. The response time and the recovery time of the device are 0.9 s and 0.5 s, respectively. After 10 cycles of &lt;i&gt;I&lt;/i&gt;-&lt;i&gt;t&lt;/i&gt;, the photocurrent does not show any significant decay, indicating excellent repeatability and cycle stability of the device. Owing to the built-in electric field formed by the Schottky junction, photo-generated electrons and holes can quickly separate and produce photocurrent in the external circuit without the need for external voltage driving. In addition, the C&lt;sub&gt;14&lt;/sub&gt;H&lt;sub&gt;31&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;P-Ti&lt;sub&gt;3&lt;/sub&gt;C&lt;sub&gt;2&lt;/sub&gt; film obtained by drop-casting on Au is composed of several layers of nanosheets that are randomly stacked, which can effectively relax the plasma momentum limitation, promote the generation of hot electrons, and contribute to the photocurrent. As the C&lt;sub&gt;14&lt;/sub&gt;H&lt;sub&gt;31&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;P-Ti&lt;sub&gt;3&lt;/sub&gt;C&lt;sub&gt;2&lt;/sub&gt;/Au Schottky junction photodetector possesses self-driven characteristics and simple fabrication process, it exhibits great potential applications in detecting weak light signals, such as in the fields of astronomy and biomedical science. The successful fabrication of this photodetector provides a new approach for designing and developing MXene-based near-infrared detectors, thus promoting further advancements in this field.

Alkoxy phosphonic acid-functionalized conjugated microporous polymers for efficient and multi-environmental proton conduction

With the dense hydrogen-bonding networks formed by the alkoxy phosphonic acid groups and guest H3PO4 molecules, CMP-Cx-P-H exhibit high proton conductivity under both humid and anhydrous conditions as well as wide temperature range (−40 to 130 °C).

Molecular structures of 1-hydroxyethane-1,1-diphosphonic acid for removing calcium sulfate scale under different pH conditions.

As an important descaling agent, 1-hydroxyethane-1,1-diphosphonic acid (HEDP) is capable of dissolving calcium sulfate scale when the pH of HEDP solution is adjusted from acidic to weakly alkaline. The molecular structures of Ca-HEDP complexes were determined to understand the impact of pH on the dissolution of calcium sulfate scale. The structures of the complexes revealed that the two phosphonic acid groups and the hydroxyl group of HEDP each provide one O atom to coordinate with the Ca ion to form a stable three-coordinate configuration under alkaline conditions. The electronic structures were investigated by interaction region indicator analysis, atoms in molecules analysis, electron localization function and natural population analysis. The deprotonation of the phosphonic acid group enhances the binding of coordinated O atoms and Ca ions as the pH increases, and weak alkalinity is the optimal process condition as strong alkaline conditions result in the precipitation of hydroxide and Ca ions.

The effect of phosphonates on lanthanide separation for surface-grafted porous zirconia

Inorganic–organic hybrid sorbents were synthesized by grafting porous zirconia with a series of aminomethylenephosphonate ligands. Sorbents with a larger number of phosphonate groups showed higher selectivity for intra-lanthanide separation.

Telechelic phosphonated rubber from metathetic depolymerization of polydienes and of waste tires

A controlled degradation process enabling polydiene depolymerization and using the olefin metathesis reaction with a phosphonated allylic chain transfer agent (CTA) is reported. This process afforded the functionalization of elastomers by phosphonate groups to lead to phosphonated telechelic polymers with a quite low dispersity. The metathetic degradation reaction proceeded successfully on waste tires to provide phosphonated telechelic polymers that can be used as secondary raw materials for various applications. This strategy is a logical solution to develop a circular economy approach concerning the recycling of the waste tires.

Biologically active calixarene phosphonic acids

Phosphorylated derivatives of organic compounds are known to be capable of inhibiting the activities of enzymes and other proteins responsible for key metabolic pathways. In this connection, the calixarene phosphonic acids are of interest as macrocyclic agents interacting with targets that may be involved in pathological cellular processes. This review presents a literature survey on the synthesis and properties of calix[4]arene phosphonic acids as inhibitors of alkaline phosphatases, protein tyrosine phosphatases, Na,K-ATPase, nucleotide pyrophosphatase/phosphodiesterase 1, and some other enzymes and proteins. Brief information is also given about the inhibitory activity of calix[4]arene derivatives bearing alkyl phosphonate or phosphinic acid groups

Stabilization of Apatite Coatings on PPENK Surfaces by Mechanical Interlocking to Promote Bioactivity and Osseointegration In Vivo.

Apatite coatings with high stability can effectively improve the surface bioactivity and osteogenic activity of implant materials. In clinical practice, the ability of apatite coatings to bond with the substrate is critical to the effect of implants. Here, we propose a strategy to construct a three-dimensional (3D) nanoporous structure on the surface of a poly(phthalazinone ether nitrile ketone) (PPENK) substrate and introduce a polydopamine (PDA) coating with grafted phosphonate groups to enhance the overall deposition of a bone-like apatite coating in the 3D nanoporous structure during mineralization. This method leads to a mechanical interlocking between the apatite coating and the substrate, which increases the stability of the apatite coating. The apatite coating confers a better bioactive surface to PPENK and also promotes osteogenic differentiation and adhesion of MC3T3-E1 osteoblasts in vitro. The samples are then implanted into rat femurs to characterize in vivo osseointegration. Micro-CT data and histological staining of tissue sections reveal that PPENK with a stable apatite coating induces less fibrous capsule formation and no inflammatory response and promotes osteogenic differentiation and bone-bonding strength. This enhances the long-term use of PPENK implant materials and shows great potential for clinical application as orthopedic implants.

Preparation of photosensitive phytic acid doped polyaniline and its application in UV-curable anticorrosive coatings

In this paper, photosensitive phytic acid (PAGA) was synthesized via the ring opening reaction of glycidyl methacrylate and phytic acid (PA), which was used to dope polyaniline (PANI). The doped polyaniline (PAGA/PANI) was added to UV-curable resin to prepare UV-curable polyaniline anticorrosive coating. The doping of PANI by PAGA can effectively improve the dispersion of PANI in coatings. Even when the amount of PAGA/PANI increased to 2.0 wt%, PANI can still achieve uniform dispersion in the UV-curable resin. The gel content test showed that with the addition of PAGA/PANI, the curing degree of the UV-cured coating did not decrease, but slightly increased, which was attributed to the introduction of multiple photosensitive groups in PAGA, compensating for the negative effect caused by PANI. The incorporation of PAGA/PANI can also enhance the adhesion of the UV-cured coating due to the presence of phosphonic group in PAGA. With the increase of the content of photosensitive groups, the adhesion of the coating showed an increasing trend. The corrosion resistance of the coating was investigated by electrochemical impedance spectroscopy, and salt spray experiments. The impedance value of the PAGA/PANI coating was two orders of magnitude higher than that of pure resin coating during 30 days of immersion, and neither rust nor blister were observed in the salt spray test for 1000 h, suggesting the significantly enhanced anti-corrosion performance with the incorporation of PAGA/PANI.

Bio-Inspired Synthetic Hydrogen-Bonded Organic Frameworks for Efficient Proton Conduction.

Hydrogen-bonded organic frameworks (HOFs) are a rising class of promising proton-conducting materials. However, they always suffer from the inherent contradiction between chemical stability and proton conduction. Herein, inspired by the self-assembly of lipid bilayer membranes, a series of aminomethylphosphonic acid-derived single-component HOFs are successfully developed with different substituents attached to the phosphonate oxygen group. They remain highly stable in strong acid or alkaline water solutions for one month owing to the presence of charge-assisted hydrogen bonds. Interestingly, in the absence of external proton carriers, the methyl-substituted phosphonate-based HOF exhibits a very high proton conductivity of up to 4.2×10-3 Scm-1 under 80°C and 98% relative humidity. This value is not only comparable to that of HOFs consisting of mixed ligands but also is the highest reported in single-component HOFs. A combination of single-crystal structure analysis and density functional theory calculations reveals that the high conductivity is attributed to the strengthened H-bonding interactions between positively charged amines and negatively charged phosphonate groups in the channel of bio-inspired HOFs. This finding demonstrates that the well-defined molecular structure of proton conductors is of great importance in the precise understanding of the relationship between structure and property.

Highly Efficient Removal of Uranium from an Aqueous Solution by a Novel Phosphonic Acid-Functionalized Magnetic Microsphere Adsorbent.

The development of adsorption materials which can efficiently isolate and enrich uranium is of great scientific significance to sustainable development and environmental protection. In this work, a novel phosphonic acid-functionalized magnetic microsphere adsorbent Fe3O4/P (GMA-MBA)-PO4 was developed by functionalized Fe3O4/P (GMA-MBA) prepared by distill-precipitation polymerization with O-phosphoethanolamine. The adsorption process was endothermic, spontaneous and kinetically followed the pseudo second-order model. The maximum uranium adsorption capacity obtained from the Langmuir model was 333.33 mg g-1 at 298 K. In addition, the adsorbent also had good acid resistance and superparamagnetic properties, which could be quickly separated by a magnetic field. XPS analysis showed that the adsorption of adsorbent mainly depended on the complexation of phosphonic acid group with uranium. This work offers a promising candidate for the application of magnetic adsorbents in the field of uranium separation and enrichment.

Highly compressible composite aerogels constructed by coaxial electrospun fibres and graphene for water sterilization

The electrospun fibres/graphene composite aerogels were assembled with the addition of amino trimethylene phosphonic acid (ATMP). Coaxial electrospinning was employed to attach nanosized-zinc pyrithione, a broad-spectrum biocide, on polyacrylonitrile (PAN) fibre surfaces. Reaction between ATMP and graphene oxide promoted the crosslinking structure of graphene-based aerogels, while producing antibacterial quaternary ammonium and attaching phosphonic acid groups to chelate the metal ions. The addition of the electrospun fibres in the composite aerogels improved the compressive stress at 50% strain by 540% upon the heat treatment at 200 °C, while the sterilization ratio of E. coli reached 100%. The heat treatment was critical for the mechanical properties of the composite aerogels because the linear chains of PAN were turned into rigid ladder polymer upon cyclization, while covalent interaction was introduced between residual carboxyl groups on graphene layers and CN groups of cyclized PAN. The electrospun fibres/graphene composite aerogels can be effectively applied to remove pathogenic bacteria, organic dyes and heavy metal ions in polluted water.

Frontispiece: Phosphoric‐Acid Retention in High‐Temperature Proton‐Exchange Membranes

There are mainly four strategies to mitigate phosphoric-acid loss for high-temperature proton-exchange membranes: (1) Chemical modification of polymer mainchains with phosphonic acid groups; (2) Introduction of stronger interaction by construction of quaternary ammonium-biphosphate ion pairs in the membranes; (3) Capillary siphoning effect provided by polymers with intrinsic micropores; (4) Doping of inorganic particles in the polymer matrix. For more information, see the Concept article by H. Tang, N. Li, K. Geng and co-workers (DOI: 10.1002/chem.202202064).

Structure and properties of a flame retardant ternary vitrimer regulated by cyclic and long-chain dicarboxylic acids

A vitrimer is a kind of polymer with a dynamic network that has received extensive attention. An epoxy monomer containing a phosphonate group (E) has been used to endow a vitrimer with flame retardancy. 1, 4-cyclohexanedicarboxylic acid (CA) was used as a diacid monomer. Dodecanedioic acid (DA) containing a long aliphatic chain was used as a third monomer to regulate the structure and properties of the vitrimer. The flame retardant properties were investigated using UL-94 vertical combustion, limiting oxygen index (LOI). The results showed that the E/1C/2D vitrimer containing CA/DA (mole ratio1:2) displays a UL-94 V-0 rating and a LOI value of 31%. Furthermore, the vitrimers possesse excellent recyclable and multiple shape memory performance. The E/1C/2D vitrimer may be structurally modified rapidly via transesterification reaction between an ester and neighboring β‑hydroxy groups at 170 °C. The recycling efficiency is nearly 100%. The tensile strength and modulus of E/1C/2D may be as high as 97 MPa and 2173 MPa, respectively. The tensile strength is not significantly decreased as a consequence of two reformation events. A simple method for the regulation of the flame retardancy and mechanical properties of vitrimers has been demonstrated.

Co-Delivery System of Curcumin and Colchicine Using Functionalized Mesoporous Silica Nanoparticles Promotes Anticancer and Apoptosis Effects.

Many natural agents have a high anticancer potential, and their combination may be advantageous for improved anticancer effects. Such agents, however, often are not water soluble and do not efficiently target cancer cells, and the kinetics of their action is poorly controlled. One way to overcome these barriers is to combine natural agents with nanoparticles. Our aim in the current study was to fabricate an anticancer nanoformulation for co-delivery of two natural agents, curcumin (CR) and colchicine (CL), with a core-shell structure. Using cancer cell lines, we compared the anticancer efficacy between the combination and a nanoformulation with CL alone. For the single-drug nanoformulation, we used phosphonate groups to functionalize mesoporous silica nanoparticles (MSNs) and loaded the MSNs with CL. Additional loading of this nanoformulation with CR achieved the co-delivery format. To create the structure with a core shell, we selected a chitosan-cellulose mixture conjugated with targeting ligands of folic acid for the coating. For evaluating anticancer and apoptosis effects, we assessed changes in important genes and proteins in apoptosis (p53, caspase-3, Bax, Bcl-2) in several cell lines (MCF-7, breast adenocarcinoma; HCT-116, colon carcinoma; HOS, human osteosarcoma; and A-549, non-small cell lung cancer). Nanoformulations were successfully synthesized and contained 10.9 wt.% for the CL single-delivery version and 18.1 wt.% for the CL+CR co-delivery nanoformulation. Anticancer effects depended on treatment, cell line, and concentration. Co-delivery nanoformulations exerted anticancer effects that were significantly superior to those of single delivery or free CL or CR. Anticancer effects by cell line were in the order of HCT-116 &gt; A549 &gt; HOS &gt; MCF-7. The lowest IC50 value was obtained for the nanoformulation consisting of CL and CR coated with a polymeric shell conjugated with FA (equivalent to 4.1 ± 0.05 µg/mL). With dual delivery compared with the free agents, we detected strongly increased p53, caspase-3, and Bax expression, but inhibition of Bcl-2, suggesting promotion of apoptosis. Our findings, although preliminary, indicate that the proposed dual delivery nanoformulation consisting of nanocore: MSNs loaded with CL and CR and coated with a shell of chitosan-cellulose conjugated folic acid exerted strong anticancer and apoptotic effects with potent antitumor activity against HCT-116 colon cells. The effect bested CL alone. Evaluating and confirming the efficacy of co-delivery nanoformulations will require in vivo studies.