Materials Chemistry Frontiers最新文献

The bis-tridentate (1,2,3-triazol-4-yl)-picolinamide (tzpa) ligands 1 and 2 were used in the formation of the luminescent di-metallic Tb(III) triple stranded helicates 3 and 4 (L₃Tb₂; L = 1 or 2). Both 3 and 4 were formed in high yield under either kinetic or thermodynamic conditions and their binding constant values were evaluated. The photophysical properties of the assemblies were analysed in the solution and solid state. The morphology of the ligands vs. the Tb(III) assemblies were significantly different as detected by SEM.

Correction for ‘Photodynamic antitumor activity of aggregation-induced emission luminogens as chemosensitizers for paclitaxel by concurrent induction of apoptosis and autophagic cell death’ by Jia Wang et al., Mater. Chem. Front., 2021, 5, 3448–3457, https://doi.org/10.1039/D1QM00089F.

Developing multiple photoresponsive polymers is crucial for creating versatile intelligent materials; however, it poses a significant challenge due to the limited availability of photoactivated moieties. Herein, we present a novel series of dual photoresponsive spiro-[4,5]-cyclohexadiene-8-one polymers exhibiting photoactivated crosslinking and switch-on fluorescence behaviors. These polymers were synthesized through a robust palladium-catalyzed [2+2+1] cycloaddition polymerization reaction of 4-phenol diazonium tetrafluoroborate and diynes. Notably, the single photoreactive spiro-[4,5]-cyclohexadiene-8-one moiety endowed dual photoresponse features to these polymers. Upon UV irradiation, the cyclohexadienone moieties underwent a 2π+2π photocycloaddition reaction to form an insoluble crosslinked polymer network. Concurrently, the photoactivated fluorescence phenomenon of the crosslinked polymers was also observed. To our knowledge, these polymers represent the first examples of merging photocrosslinking and fluorescence turn-on properties into one single functional group. By harnessing the unique photocrosslinking and photoactivated fluorescence properties, we successfully imprinted 2D and 3D photopatterns for lithographic applications. These intriguing results provide an alternative design strategy of multiple photoresponsive polymers for fluorescent labelling and 2D/3D optical security.

Aptamers, despite their specific targeting capabilities and widespread applications in various research domains, face a significant hurdle in the biomedical research area due to their rapid degradation by nucleases. To address this challenge, this study introduces an innovative development in the form of polymeric aptamer probes (PAPs) designed to enhance in vivo cancer tissue recognition and targeting. This study outlines the synthesis of PAPs, which leverage the strain-promoted alkyne–azide cycloaddition (SPAAC) strategy to construct these nanoprobes. By sequentially linking individual DBCO or N₃ group-decorated AS1411 aptamers that target nucleolin overexpressed on tumor cells, the resulting PAPs exhibit significantly enhanced stability against enzymatic degradation and superior binding affinity and internalization ability compared to single aptamers across a range of cancer cell lines. In vivo experiments have further validated the superior tumor targeting and retention capabilities of the prepared PAPs, thus underscoring their potential for precise cancer diagnosis and therapy.

Gold nanoparticles are extensively employed in the field of electrocatalytic nitrite reduction for ammonia synthesis, due to their exceptional conductivity and remarkable stability. However, the performance of a single metal is often limited and by combining different metals, the overall performance can be significantly improved to meet specific needs and application scenarios. The regulation of the interaction between loaded gold nanoparticles and metal oxide support materials represents an effective strategy for facilitating the reduction of nitrite to ammonia. In this work, we prepared three different structural morphologies of cerium dioxide (CeO₂) – cubic (c-CeO₂), rod-like (r-CeO₂) and granular (p-CeO₂), by modulating the hydrothermal temperature. The effect of the morphology of the CeO₂ carriers on the surface structure of the composite catalyst, CeO₂@Au, was systematically studied and its performance of the electrocatalytic reduction of ammonia from nitrite was explored. It was found that c-CeO₂ loaded with Au nanoparticles possessed better electrocatalytic performance with an ammonia yield of 4007.9 μg h⁻¹ mg_cat⁻¹ and a Faraday efficiency of 91.2% compared to r-CeO₂ and p-CeO₂. The results of the characterisation tests, conducted using scanning electron microscopy (SEM), elemental mapping analysis (EDS) and inductively coupled plasma (ICP), demonstrate that c-CeO₂ exhibits enhanced crystallinity, a reduced particle size and a more uniform dispersion. Therefore, c-CeO₂ is able to load more Au nanoparticles during the complexation process with Au, which in turn possesses more reactive active sites. In addition, the results of transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) showed that after the complexation of c-CeO₂ with Au, some of the lattice fringes of c-CeO₂ were distorted with defects leading to an increase in the content of oxygen vacancies, which greatly improved the active area of the catalyst. These physicochemical properties endow the c-CeO₂@Au catalysts with excellent electrocatalytic nitrite-to-ammonia activity.

Photodynamic therapy (PDT) is a well-established minimally invasive cancer treatment, yet its effectiveness in treating hypoxic tumors is limited due to oxygen scarcity, hindering the production of reactive oxygen species (ROS). Phthalocyanines, notable for their remarkable optoelectronic attributes and structural flexibility, have emerged as a class of photosensitizers with potential to enhance PDT. This review highlights innovations in the development of self-assembled phthalocyanine-based nano-photosensitizers, underscoring their potential to mitigate the obstacles posed by hypoxia in PDT. It details advancements in self-assembly methodologies and their applications to augment the therapeutic impact of PDT in hypoxic tumors, encompassing oxygen supply augmentation, metabolic pathway modulation, development of phthalocyanine-based nano-photosensitizers for photothermal therapy (PTT), type I PDT photosensitizers and combination therapy. It concludes with an overview of the current challenges and future prospects of phthalocyanine-based nano-photosensitizers in PDT. By reviewing recent progress, this paper aspires to offer pioneering insights into the conception of novel nano-photosensitizers, engineered to counteract hypoxia and circumvent the intrinsic limitations of PDT.

Keratin derived materials are still underexploited due to the little understanding of their chemical versatility. Whereas many protein based materials achieve flexibility by crosslinking or interpenetrating with synthetic polymers, we assessed the effect of reductive treatments on aqueous media. Hydrazine sulphate (HZN) and ascorbic acid reduction were compared. The reduced material is bendable and stretchable, whereas the original keratin hydrogel is brittle. This would imply a technological leap in protein materials. Both reductive treatments would achieve reduced keratins by the reduction of oxidised cysteines which leads to a change in the polypeptide chain interaction by a decrease in electrostatic repulsion and swelling. Moreover, in contrast with the ascorbic acid treatment, when higher levels of HZN are employed, the effect of residual sulphates lead to the interchain closeness of the more mobile domains acting as physical crosslinkers, leading to compressed structures with narrower pores. This suggests that the flexible properties of the hydrogel could be related not only to the reduction of the hydrogel but also to the interaction of the sulphate ions with the keratin structure. As a result, the reduction of sulfinic and sulfenic groups to thiol, along with the incorporation of sulphate ions into the structure, impart the material with an elongation at break ranging between 10–25%, nano-scale pores approximately 2 nm in size, swelling capacity of around 50%, all while preserving the biocompatibility observed in the original material tested across two cell lines comprising fibroblasts and keratinocytes.

3D foam-like composites with a large specific surface area and a well-distributed interconnected pore structure have been recognized as promising materials for energy storage devices. In this study, a novel composite electrode (PEUS-Mn-PS) consisting of a 3D foam-like PEUS matrix embedded with manganese dioxide (MnO_x) was prepared using a simple and facile method. The PEUS matrix was fabricated by incorporating poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and water polyurethane (PU), where a sacrificial template of poly(3,4-ethylenedioxythiophene) (PEDOT)-decorated Ni foam (NF) was utilized. Specifically, surface modification of NF with a thin layer of PEDOT resulted in the formation of a more regular 3D interconnected scaffold of PEU with more hydrophilic surface, facilitating homogeneous formation of the electrode materials and electrolyte infiltration. Benefiting from the high conductivity of PEDOT:PSS, large surface area provided by PEU, and high capacity offered by MnO_x, the resulting flexible PEUS-Mn-PS electrode exhibited an exceptional areal specific capacitance of 681.7 mF cm⁻² (∼486.9 F g⁻¹) at 1 mF cm⁻², much larger than 358.9 mF cm⁻² of the PUS-Mn-PS electrode prepared without PEDOT modification and 318.7 mF cm⁻² of the NF-Mn electrode synthesized through direct electrodeposition of MnO_x on NF. The resulting PEUS-Mn-PS electrode allowed the assembled solid-state symmetric flexible SC to achieve an impressive energy density of 0.043 mW h cm⁻² at a power density of 2.24 mW cm⁻², while maintaining excellent electrochemical performance even under various bending angles. This work provides a new approach to designing high-performance flexible SC electrode materials using a simple, cost-effective, and environmentally friendly method.

Low-molecular-weight organogels (LMWGs) with π-conjugated structures typically exhibit excellent photoluminescent properties and have significant potential in optoelectronic materials, sensing, and detection applications due to their large specific surface areas and high sensitivity. Conventional organogelators usually contain multiple amide bonds and long flexible chains to facilitate gelation. In contrast, non-conventional π-conjugated organogelators lack flexible chains, offering enhanced atomic economy. Furthermore, the suppression of non-radiative decay caused by the motion of flexible units could lead to higher emission efficiency. Notably, recent research has indicated that rigid chemical structures are essential for achieving ultra-long room-temperature phosphorescence (RTP) in organogels. This review highlights the structures, photoluminescent properties, and applications of non-conventional LMWGs, and discusses future perspectives and challenges in this emerging field.

Based on their stimuli-responsiveness, smart materials are able to undergo controllable physicochemical changes. As compared to the responsiveness to one specific stimulus, multiple stimuli-responsiveness would make smart materials adaptable to diverse environments, which is highly desired in the design of smart materials but appreciably more difficult to realize. Herein, an ammonium surfactant (SPA) based on spiropyran is designed for complexing with carboxymethylcellulose through an electrostatic route, affording a soft cellulose material (CMC–SPA) in solvent-free conditions. Thanks to the molecular design of SPA and the anisotropic arrangement of cellulose on SPA molecules, CMC–SPA exhibits triple stimuli-responsiveness by responding to light, heat and humidity. With good thermodynamic stabilities of different color states, CMC–SPA could well record optical information by changing colors under UV and visible irradiations. More interestingly, linear relationships between UV-visible absorption and temperature/humidity are established, endowing CMC–SPA with the functions of recording ceiling temperatures in inaccessible scenarios and indicating real-time environmental humidity. This study provides a design strategy for fabricating multiple stimuli-responsive materials, affording a new route for gaining smart biomaterials from biomacromolecules.