Cyclotriphosphazene-based Derivatives for Antibacterial Applications: An Update on Recent Advances

Phosphazene Tripeptide Conjugates: Design, Synthesis, In Vitro Cytotoxicity and Genotoxicity, Molecular Interactions in Binding Pockets on Human Breast and Colon Cancer Cell Lines

The biological activity of both cyclophosphazenes and peptides makes these compounds important for new studies in medicinal chemistry. For this purpose, five different phosphazene-peptide conjugates synthesized from dichlorocyclotriphosphazene and tyrosine-containing tripeptides. The synthesized compounds were evaluated for their in vitro cytotoxic activities against human breast (MCF-7) and colon (Caco-2) cancer cell lines using MTT assay. The derivatives induced cell death through DNA damage, with notable effects in Caco-2 cell lines. Specifically, DTVV, DTVG, and DTVA were cytotoxic at 50 and 100 μM, while DTVP and DTVM were effective at 25, 50, and 100 μM. DTVM outperformed Tamoxifen at 50 μM in the MCF-7 cell line. DNA damage studies of the compounds were performed using the comet assay method, evaluating tail length, tail density, olive tail moment, head length, and head density parameters. The findings indicated that cell death occurred via a DNA damage mechanism. The molecular intricacies of DTVA, DTVG, DTVM, DTVP and DTVV within the VEGFR2 kinase domain (3VHE) and Cyclophilin_CeCYP16-Like Domain (2HQ6) binding pockets and various interactions, docking scores and potential activities of these derivatives were investigated. The differences in docking scores and interaction profiles highlight the potential efficacy and specificity of these compounds in targeting breast and colon cancer cells. These findings highlight the potential of phosphazene-peptide derivatives as therapeutic agents in cancer treatment.

Metal-free small molecule-based piezoelectric energy harvesters

Organic and metal-free molecules with piezoelectric and ferroelectric properties have gained wide interest for their applications in the domain of mechanical energy harvesting due to their desirable properties such as light weight, thermal stability, mechanical flexibility, feasibility to achieve high Curie temperatures, and ease of synthesis. However, the understanding and design of these materials for piezoelectric energy harvesting applications is still in its early stages. This review paper presents a comprehensive overview of the fundamental characterization of piezoelectricity for a range of organic ferro- and piezoelectric materials and their composites. It also discusses the limitations of traditional piezoelectric materials and highlights the advantages of organic materials in this area in the introduction part. In addition, the paper provides a detailed description of peptide-based and other biomolecular piezoelectric materials as a bio-friendly alternative to current materials. This perspective aims to guide researchers in designing functional organic materials and composites for practical mechanical energy harvesting applications and to highlight current limitations and future perspectives in this emerging area of research.

Design and Piezoelectric Energy Harvesting Properties of a Ferroelectric Cyclophosphazene Salt

Cyclophosphazenes offer a robust and easily modifiable platform for a diverse range of functional systems that have found applications in a wide variety of areas. Herein, for the first time, it reports an organophosphazene-based supramolecular ferroelectric [(PhCH2 NH)6 P3 N3 Me]I, [PMe]I. The compound crystallizes in the polar space group Pc and its thin-film sample exhibits remnant polarization of 5 µC cm-2 . Vector piezoresponse force microscopy (PFM) measurements indicated the presence of multiaxial polarization. Subsequently, flexible composites of [PMe]I are fabricated for piezoelectric energy harvesting applications using thermoplastic polyurethane (TPU) as the matrix. The highest open-circuit voltages of 13.7 V and the maximum power density of 34.60 µW cm-2 are recorded for the poled 20 wt.% [PMe]I/TPU device. To understand the molecular origins of the high performance of [PMe]I-based mechanical energy harvesting devices, piezoelectric charge tensor values are obtained from DFT calculations of the single crystal structure. These indicate that the mechanical stress-induced distortions in the [PMe]I crystals are facilitated by the high flexibility of the layered supramolecular assembly.

Preparation of Strong and Thermally Conductive, Spider Silk-Inspired, Soybean Protein-Based Adhesive for Thermally Conductive Wood-Based Composites

The development of formaldehyde-free functional wood composite materials through the preparation of strong and multifunctional soybean protein adhesives to replace formaldehyde-based resins is an important research area. However, ensuring the bonding performance of soybean protein adhesive while simultaneously developing thermally conductive adhesive and its corresponding wood composites is challenging. Taking inspiration from the microphase separation structure of spider silk, boron nitride (BN) and soy protein isolate (SPI) were mixed by ball milling to obtain a BN@SPI matrix and combined with the self-synthesized hyperbranched reactive substrates as amorphous region reinforcer and cross-linker triglycidylamine to prepare strong and thermally conductive soybean protein adhesive with cross-linked microphase separation structure. These findings indicate that mechanical ball milling can be employed to strip BN followed by combination with SPI, resulting in a tight bonded interface connection. Subsequently, the adhesive's dry and wet shear strengths increased by 14.3% and 90.5% to 1.83 and 1.05 MPa, respectively. The resultant adhesive also possesses a good thermal conductivity (0.363 W/mK). Impressively, because hot-pressing helps the resultant adhesive to establish a thermal conduction pathway, the thermal conductivity of the resulting wood-based composite is 10 times higher than that of the SPI adhesive, which shows a thermal conductivity similar to that of ceramic tile and has excellent potential for developing biothermal conductivity materials, geothermal floors, and energy storage materials. Moreover, the adhesive possessed effective flame retardancy (limit oxygen index = 36.5%) and mildew resistance (>50 days). This bionic design represents an efficient technique for developing multifunctional biomass adhesives and composites.

Cyclotriphosphazene-Based "Butterfly" Fluorescence Probe for Lysosome Targeting

A cyclotriphosphazene-based "butterfly" fluorescence probe HCCP-MNI bearing two naphthalimide and morpholine units were developed for lysosome targeting. The synthesized HCCP-MNI exhibited stable fluorescence signals and was cytocompatible in the given concentration range. Co-localization experimental results showed that cells treated with the HCCP-MNI and a commercial dye (Lyso-Tracker Red DND-99) had overlapped fluorescence signals, demonstrating its targeting specificity to lysosomes. The developed HCCP-MNI may be used for cell tracking applications associated with the functionalities of lysosomes.