Materials Advances最新文献

In recent years, non-contact fluorescence intensity ratio (FIR)-based luminescent thermometry has garnered significant attention for its potential applications in various fields, including electromagnetic environments, micro-temperature fields, and thermally harsh conditions. In this study, we focus on the synthesis and characterization of Y₂Mo₃O₁₂ co-doped with 2% Pr³⁺ and 15% Yb³⁺ nanoparticles using a sol–gel reaction method. The phase purity and luminescence characteristics of the synthesized nanoparticles were thoroughly evaluated using techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL). Upon excitation with 457 nm light, intense emissions from the ³P₀, ³P₁ and ¹D₂ excited states were observed. The temperature sensing capabilities of the nanoparticles were investigated within the range of 298–448 K. Furthermore, the thermal and non-thermal coupling levels of Pr³⁺ and Yb³⁺ ions were analysed using fluorescence intensity ratio technique (FIR). Our results demonstrated that Y₂Mo₃O₁₂ co-doped with 2% Pr³⁺ and 15% Yb³⁺ exhibited high sensitivity in temperature sensing, with a maximum relative sensitivity of 11.2% K⁻¹ observed at 298 K. Notably, temperature uncertainty (δT) values were exceptionally low within the range of 0.11–0.63 K. These findings underscore the potential of Y₂Mo₃O₁₂:Pr³⁺/Yb³⁺ nanoparticles in optical thermometry applications, thus highlighting their effectiveness as temperature sensors in various environments.

Highly luminescent carbon quantum dots were produced from banana peels (BP-CQDs) using a facile one-step method without the incorporation of chemicals. BP-CQDs were comprehensively characterized using techniques like TEM, FT-IR, XRD, and XPS analyses. The synthesized BP-CQDs exhibited outstanding optical characteristics, displaying a vibrant green color under UV light and a quantum yield of 41%. These properties enabled them to function as effective on–off fluorescent nanoprobes for the precise and sensitive detection of hazardous Cr(VI) concentrations below regulatory limits, leveraging the inner filter effect (IFE) and a static quenching mechanism. The detection limit is calculated to be in the nanomolar range i.e., 60.5 nM. Consequently, the BP-CQDs + Cr(VI) system also acted as a selective off–on sensor for the reductant ascorbic acid (AA) with 86 nM limit of detection. This effect was due to AA's reduction of Cr(VI) to Cr(III) species, which eliminated the IFE and restored the fluorescence of the BP-CQDs. Moreover, efforts have been undertaken to create a low-cost, portable electronic device utilizing spectroscopy sensors to detect heavy metal pollutant concentrations in the test samples. The experimental results affirm the effectiveness of the portable electronic device as a detector for Cr(VI) in test samples. This study sets the groundwork for creating carbon quantum dots (CQDs) with enhanced properties by using banana peels as a biowaste precursor to detect the concentrations of Cr(VI) and AA.

The expanding potential of 2D MXenes opens up promising avenues for flexible biomedical applications. MXenes, a new family of two-dimensional materials with exceptional mechanical, electrical, and chemical properties, have garnered attention for their potential to revolutionize healthcare. These properties enable MXenes to interface seamlessly with biological systems, offering innovative diagnostics, therapeutics, and regenerative medicine solutions. In the biomedical domain, MXenes have shown promise in antibacterial applications, drug delivery, biosensing, photothermal therapy, and tissue engineering, and their biocompatibility and ease of functionalization enhance their utility in real-world healthcare settings. Their large surface areas make them ideal for drug delivery systems, enabling precise encapsulation and release of therapeutic molecules. High electrical conductivity of MXenes has opened new possibilities for neuroprosthetics and brain–machine interfaces, potentially restoring lost functions. Their excellent mechanical properties, biocompatibility, and corrosion resistance make MXenes promising for durable orthodontic devices. Furthermore, their surface-modification capabilities allow for innovative biosensing and diagnostic platforms for sensitive disease detection. MXenes are compatible with imaging techniques, making them suitable contrast agents that can enhance the resolution of medical imaging. MXenes also hold potential in wearable health monitoring devices, advanced bioelectronics, and smart implants, bridging the gap between laboratory research and clinical deployment. However, there are certain challenges regarding their biocompatibility, long-term effects, and large-scale production, which need further research to ensure their safe integration into biomedical applications. This review presents the advancements in the biophysical fabrication of 2D MXenes and their antimicrobial properties and biocompatibility, along with their applications in diagnostics, imaging, biosensing, and therapeutics.

This review presents the design and experimental analysis of metamaterials with tunable properties for biomedical applications. Five different metamaterials, such as lightweight metamaterials, pattern transformation metamaterials, negative compressibility metamaterials, pentamode metamaterials and auxetic metamaterials, are discussed in detail with emphasis on their mechanical and biological features that are primarily applicable in the field of biomedical technology. Various indigenous structures of the metamaterials are carefully analysed for metamaterial design and their influence on mechanical performance is studied. Thus, this review comprehensively summarizes the different additive manufacturing techniques implemented for biomedical metamaterials and their influence on their mechanical properties. Finally, the mechanical properties and deformation mechanisms for different geometries and structures of all the above-mentioned metamaterials are analyzed.

Green synthesis of silver nanoparticles (AgNPs), using medicinal plants, is widely practiced due to the diverse bioactive compounds present in these plants, which can act synergistically with the AgNPs. Notably, the rhizome of Trillium govanianum Wall Ex. Royle is rich in bioactive phytochemicals such as steroids, saponins, glycosides, and fatty acids. This study aims to synthesize and characterize AgNPs mediated by the Trillium govanianum rhizome (^TGRAgNPs) and comprehensively investigate their biological activities. The results indicated that phytochemicals in the rhizome may function as reducing and capping agents in the synthesis of ^TGRAgNPs. Overall, this study presents a simple, rapid, cost-effective, and eco-friendly method for nanoparticle production. Subsequently, the ^TGRAgNPs were characterized using UV-vis spectroscopy, FTIR, XRD, DLS, zeta potential, SEM-EDX, and TEM analyses. GC-MS analysis of the extract identified several phytochemicals that might play crucial role in the synthesis of ^TGRAgNPs. Moreover, ^TGRAgNPs demonstrated significant antioxidant, anticancer (against HCT-116 cell lines), anti-inflammatory, and DNA protection activities. Additionally, hemolytic assay confirmed the non-toxic and hemo-compatible nature of ^TGRAgNPs at all tested concentrations. The findings suggest that the green synthesized ^TGRAgNPs have promising potential as biocompatible antioxidant, anti-inflammatory, and anticancer agents in biomedicine.

The current work reports a novel and effective solvolysis process for the treatment of complex poly(ethylene terephthalate) (PET) waste using neopentyl glycol (NPG) as a depolymerization agent, which to date has not been studied much for chemical recycling. Different complex PET waste samples (multilayers and textiles) were conditioned for glycolysis in the presence of NPG and zinc acetate as a catalyst. The reaction parameters, including temperature and NPG/PET molar ratios, were optimized to maximize the yield of the bis-(hydroxy neopentyl) terephthalate (BHNT) monomer. The reaction progress was gravimetrically determined, and the resulting BHNT monomers were characterized by means of various techniques (FTIR, DSC, and NMR). A novel purification step with active carbon was developed in order to remove dyes and other impurities present in the raw products. The results indicated that an NPG/PET molar ratio of 6 : 1 and a reaction temperature of 200 °C were optimal for achieving high PET conversion and raw BHNT yield. The purification process successfully enhanced the purity of BHNT, increasing the presence of the monomer in the purified samples from 60% to 95% in mol and reducing the oligomer and by-product content. The obtained products have the potential to replace fossil-based NPG in the synthesis of resins or coatings.

Metal substitution is an important way to tune the magnetic properties of ferrites. In the present study, to investigate the effects of Mn substitution on the magnetic properties and millimeter wave absorption properties on ε-Fe₂O₃ for the first time, Mn-substituted epsilon iron oxides, ε-Mn_xFe_2−xO_3−x/2 (x = 0 (Mn0), 0.10 (Mn1), and 0.20 (Mn2)) were synthesized by sintering iron oxide hydroxide with manganese hydroxide in a silica matrix. Transmission electron microscopy shows particle sizes of 18.7 ± 5.8 nm (Mn0), 19.0 ± 6.2 nm (Mn1), and 19.8 ± 6.7 nm (Mn2). Energy dispersive X-ray spectroscopy confirms a uniform manganese distribution across all particles, while the powder X-ray diffraction patterns demonstrate that ε-Mn_xFe_2−xO_3−x/2 has an orthorhombic crystal structure with a space group of Pna2₁ (e.g., the lattice constants in Mn2 are a = 5.1031(4) Å, b = 8.7759(8) Å, and c = 9.4661(7) Å). As the Mn substitution ratio increases, the Curie temperature decreases from 487 K (Mn0) to 469 K (Mn2). As for the magnetic properties at 300 K, the coercive field increases from 17.2 kOe (Mn0) to 18.2 kOe (Mn2), while the saturation magnetisation decreases from 17.1 emu g⁻¹ (Mn0) to 13.9 emu g⁻¹ (Mn2), with increasing substitution ratio. Terahertz time-domain spectroscopy demonstrates that the samples exhibit electromagnetic wave absorption in the millimetre-wave region, due to zero-field ferromagnetic resonance. As the Mn substitution ratio increases, the resonance frequency increases from 174 GHz (Mn0) to 182 GHz (Mn1) and 187 GHz (Mn2). Due to the substitution of Fe³⁺ with Mn²⁺, the saturation magnetisation decreases and the coercive field and the resonance frequency increase.

In the search for bipolar organic materials as electrodes in rechargeable batteries, we report peri-diselenolo-substituted 1,8-naphthalimides (NIs). The molecular architecture consists of structural motifs comprising a naphthalimide core, the peri-diselenide bridge, hydrogen or halogens at positions 3 and 6, and an alkyl chain with a fixed length of 4 and 8. The resulting architecture is unprecedented in the naphthalimide chemistry and quantum chemical modelling was employed to rationalize the new design better. The NI-derivatives are prepared starting from tetra-halogenated naphthalic anhydride via nucleophilic substitution at both peri-positions in the respective imide. Non-covalent interactions facilitate the NIs self-organization into ordered nanostructures studied by SEM, PXRD, solid-state NMR spectroscopy and molecular modelling. The electrochemical properties of NI-derivatives are analysed in half lithium-ion cells with ionic liquid electrolytes. By comparing the experimentally determined potentials with the theoretically calculated ones, the mechanism of electrochemical oxidation and reduction is deduced. It is shown that below 2.0 V, NIs interact with a maximum of 6Li⁺ due to the sequential reduction of the diselenide bridge and the carbonyl groups, whereas above 4.0 V, the oxidation of NIs takes place with the participation of the electrolyte counterion TFSI⁻ as a result of the involvement of Se atoms and carbons in the naphthalene unit. The hydrogen and halogen substituents affect both the self-organization, reduction and oxidation of NIs. The structural, morphological and compositional changes of the NIs after prolonged cycling are discussed based on ex situ XRD, SEM/EDS and EPR analyses. The data demonstrate that a molecular architecture based on peri-diselenolo-1,8-naphthalimide derivatives could be used to design new classes of organic bipolar electrodes.

Photodynamic therapy (PDT) is an emerging clinical tool that uses light as an agent unleashing cytotoxic activity for treating cancer and other diseases, including those showing drug resistance. One of the main areas of research to fully implement PDT as a real alternative to chemo or radiotherapy is the development of improved photosensitizers (PSs). This work aims to contribute to the design of novel PSs able to generate reactive oxygen species (ROS) upon activation with light within the biological window (deep red or near-infrared region) while being non-toxic under dark conditions (heavy-atom-free). For this, we have chosen BODIPY-based covalent dimers directly linked through their 3-position as model structures. This molecular scaffold has been previously tested as a fluorescent probe to stain cells, but not as a PS for ROS generation under red illumination. Using readily available synthetic protocols, we have changed the steric hindrance around the linkage and added functional groups suited to enhance targetable biorecognition and solubility in physiological media. The spectroscopic characterization confirms that these dimers are photoactivated in a spectral window approaching 700 nm and display noticeable fluorescence signals beyond this wavelength, together with a notable generation of singlet oxygen. Encouraged by these photophysical signatures, we conducted in vitro trials in cancer cells. These assays ratify the ability of most of the herein reported dimers to sensitize ROS and induce cell death upon long-wavelength illumination.

This study presents a novel dissolving microneedles (MN) formulation designed to deliver alpha arbutin (AA) and ascorbic acid for hyperpigmentation treatment. Utilizing hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP-K90), we successfully prepared and characterized MN arrays with high drug loading efficiencies of 89.01% for AA and 94.09% for ascorbic acid. A pioneering liquid chromatography–tandem mass spectrometry (LC–MS) technique was developed for simultaneous drug quantification, achieving precision and accuracy as per FDA guidelines. Our MN demonstrated excellent mechanical properties, with effective skin penetration and dissolution within 5 minutes and permeation rates of 4.28% h⁻¹ for AA and 3.61% h⁻¹ for ascorbic acid. This innovative approach offers a promising platform for the transdermal delivery of active compounds, highlighting significant advancements in drug delivery technology.