Molecular Systems Design & Engineering最新文献

Micro/nano-robots (MNRs) have gained attention as a rapidly developing field with significant potential in advanced therapies and futuristic solutions. These self-propelled robots offer a promising strategy to enhance monitoring, overcome diffusion limitations, and interact effectively with target factors. Research in MNRs has become highly influential, especially in addressing critical issues like cancer. The progression from passive micro- and nanomaterials to active MNRs and ultimately to intelligent MNRs has led to advancements in motion abilities, multifunctionality, adaptive responses, swarming behaviour, and communication among robots. Nanorobotics, featuring sophisticated submicron devices made from nanocomponents, holds great promise for revolutionizing the healthcare industry. This review aims to highlight recent progress in propulsion mechanisms, including chemically controlled micromotors, field control, and biohybrid approaches, which serve as power sources for various biomedical and environmental applications. These applications utilize different energy sources such as magnetic, light, auditory, electric, and chemical reactions, particularly in drug delivery systems for cancer treatment. This review also discusses the challenges and future directions in the practical implementation of smart MNRs, paving the way for their real-world applications.

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Epoxy resins have been utilized across various industries due to their superior mechanical and chemical properties. However, discovering the optimal design of epoxy resins is challenging because of the large chemical space of polymer systems. In this study, we adopted a data-driven approach to develop an effective prediction system for epoxy resin. In particular, we constructed a database of 789 epoxy resins, encompassing four key properties: density, coefficient of thermal expansion, glass transition temperature, and Young's modulus, obtained through molecular dynamics simulations. We devised descriptors that effectively represent epoxy resins. Ultimately, a machine learning model was trained, successfully predicting properties with reasonable accuracy. Our predictive model is a generalized model that was verified across various types of epoxy resins, making it applicable to all kinds of epoxy and hardener combinations. This achievement enables large-scale screening over numerous polymers, accelerating the discovery process. Further, we conducted an in-depth analysis of the important features that have a high impact on the epoxy resin. This provides valuable insights into the structure–property relationship which can guide researchers in designing new epoxy resins.

We report a new synthetic concept for converting isotropic ionic molecules into thermotropic ionic liquid crystals by forming [2]rotaxane structures. Our results demonstrate the synthesis of liquid-crystalline (LC) rotaxane from an ionic axle molecule as a mesogen core, and a molecular ring as flexible tails, neither of which possess LC properties. The [2]rotaxane obtained exhibited an interdigitated smectic A phase at around 140 °C. A simple mixture of the axle and the ring, which cannot form a rotaxane structure, did not show an LC phase. A [2]rotaxane compound having a ring with shorter flexible tails did not show an LC phase, either. These comparisons revealed that the integration of the mesogen core and flexible tails of a sufficient length in one molecule via the rotaxane structure enables the emergence of LC nature. Our results prove that the rotaxane structure serves as a connection to spatially introduce flexible tails into the mesogen core, pioneering a new approach to LC molecular design.

Silicon oxide nanospheres (SiOC) have been considered one of the key candidates for the next generation of high-energy-density anode materials. Nevertheless, the intrinsic limitations of their design impede their large-scale commercial deployment, including large volume expansion, poor electrical conductivity, and low initial coulombic efficiency (ICE). The application of a polymer coating represents a beneficial modification. Herein, a composite SiOC anode is synthesized by constructing poly(hexaazatrinaphthalene) (PHATN) on the surface of boron doping-induced self-assembled SiOC nanospheres. The SiOC nanospheres change from a monodisperse structure to a regular and ordered arrangement by self-assembly, which improves the structural stability. A special polymer, PHATN, is selected for its unique structure, which introduces a dynamic conversion mechanism to the material. During the lithium intercalation process, –CN– groups in the PHATN coordinate with Li⁺ to form –C–N–Li– bonds on the PHATN molecule layer. The dynamic volume change of the PHATN molecule allows room for the volume expansion of SiOC, thus providing excellent protection against structural collapse. After 1000 deep cycles, the capacity of the composite anode can be maintained at 623.7 mA h g⁻¹, showing considerable stability and superior specific capacity. PHATN simultaneously repairs the surface defects of the SiOC assemblies and enhances the performance of the SEI membrane, increasing the ICE from 40% to 50%, which exhibits better electrochemical performance.

The local interpretable model-agnostic explanations method was applied to identify substructures that represent the mutagenicity of chemical compounds using machine learning models. Random forest and extremely randomized trees were used to build models to be explained using the Hansen and Bursi Ames mutagenicity datasets. The models were analyzed using precision, recall, F1, and accuracy metrics. The aim of this study is to address the challenge of identifying substructures that indicate the mutagenicity of chemical compounds. The goal is to provide stable and consistent explanations for the mutagenicity of chemical compounds, which is crucial for trust and acceptance of the findings, especially in the sensitive field of computational toxicology. This approach is significant as it contributes to the interpretability and explainability of machine learning models, particularly in the context of identifying substructures associated with mutagenicity, thereby advancing the field of computational toxicology. Identifying substructures that represent the mutagenicity of chemical compounds is important because it can help predict the potential toxicity of new chemical compounds. This is particularly relevant in fields such as drug development and environmental toxicology, where the potential risks of exposure to new compounds need to be carefully evaluated. Some examples of chemical compounds that have been identified as mutagenic include epoxides, N-aryl compounds, nitro compounds, aromatic amines, N-oxides, nitro-containing compounds, and polycyclic aromatic hydrocarbons with a bay-region. These examples demonstrate the importance of identifying and studying mutagenic chemical compounds to better understand their potential risks and adverse effects on human health and the environment.

To mitigate food losses and ensure a robust cold chain in transportation, sensors play a pivotal role in swiftly and visibly monitoring storage conditions. The most commonly used indicators for reporting temperature violations are based on devices capable of signaling when a threshold temperature has been reached or exceeded or on disposable colorimetric sensors. A potential alternative, which uses reusable colorimetric sensors, may come from utilizing systems capable of displaying reversible color changes upon temperature variations; in this regard, molecules exhibiting thermo- and photochromic properties such as N-salicylideneaniline derivatives (anils) have emerged as promising candidates due to the simplicity of their synthesis and their ability to respond to temperature and light stimuli. In this study we have synthesized a family of anils through mechanochemistry, focusing on H/F substituents on the bromoaniline residue. The compounds were fully characterized using XRD and thermal techniques, and their thermo- and photochromic properties were explored via infrared spectroscopy. Among the series, the most suitable compound, i.e., a photochromic one showing a neat color change (from white to red/orange) quickly naked eye-detectable and whose back reaction is slow or virtually negligible at low temperatures, was identified and incorporated into a carboxymethyl cellulose (CMC) biopolymer matrix to produce a composite film, which was further characterized via XRD, thermal analyses and mechanical tests. The selected compound maintained its photochromic behavior upon embedding, and UV irradiation induced a color change in the film from colorless to red, while reversibility was evaluated at different temperatures (−19 °C, 4 °C and RT) using UV-vis spectroscopy. The composite film maintained a deep red color at −19 °C and 4 °C for seven weeks, while rapidly reversing to white/yellowish at room temperature, making it a suitable candidate for the development of sensors for cold chain transport and scenarios requiring rapid visual inspection of storage conditions.

Similar sizes and boiling points of acetylene (C₂H₂) and carbon dioxide (CO₂) make CO₂ separation from C₂H₂/CO₂ mixtures challenging. In this work, a pillared-layer ultramicroporous Zn-mipa-datz material featuring a C₂H₂-matching cavity was successfully prepared to achieve high-efficiency C₂H₂/CO₂ separation. The separation performance of Zn-mipa-datz on C₂H₂/CO₂ mixtures was investigated through gas adsorption isotherms and dynamic breakthrough experiments. Zn-mipa-datz possessed high C₂H₂ separation efficiency for C₂H₂/CO₂ mixtures. The molecular simulation demonstrated that the strong C₂H₂–host interaction was achieved by the synergistic effect of C–N electrostatic interactions and C–H⋯N H bonds.

Post-SELEX modifications assisted by in silico modelling are powerful tools to improve the performance of aptamers, by providing a rational approach for the selection of modified-versions of aptamers. In this study, a complete in silico analysis of the three-dimensional structure of a previously selected DNA aptamer (Apt5) against staphylococcal enterotoxin A (SEA) was performed. Locked nucleic acid (LNA) modifications were introduced in key locations and their effect on the aptamer structure and docking were evaluated. Promising LNA aptamers were then synthetized and their dissociation constants (K_D), as well as stability, were evaluated. From the in silico analysis, it was possible to identify three promising LNA variations that did not affect drastically the three-dimensional structure and the molecular docking with the toxin. The K_D of the LNA aptamers were higher than the DNA aptamer (Apt5: K_D = 13 ± 2 nM, LNA13: K_D = 157 ± 39 nM, LNA14: K_D = 74 ± 24 nM, LNA15: K_D = 143 ± 28 nM), but remained in the low nanomolar range. Even so, the K_D of LNA14 was not significantly different (P < 0.05) compared to the value of the original aptamer and the introduction of LNA increased its thermal stability, increasing the range of functionality of the original aptamer. However, the introduced modifications were not enough to increase the biological stability of the aptamer, remaining susceptible to a complete degradation by endonucleases and exonucleases in 5 minutes. Altough partial modifications with LNA may not be able to overcome all the limitations of DNA aptamers, post-SELEX modifications assisted by in silico modelling have shown promising results in predicting functional modified aptamers, avoiding a time-consuming and expensive trial and error approach.

Polypeptide fusion tags that can direct the assembly of folded proteins into supramolecular networks are attractive for creating functional biomaterials. A practical challenge is identifying polypeptide sequences that form supramolecular networks in response to specific user-controlled stimuli, which is advantageous for producing polypeptide–protein fusions using cell-based expression hosts. Here, we report an N-glycosylation tag, (GGGSGGGSGGNWTT)₁₀ or “NGT,” that assembles into a supramolecular network at reduced temperatures when fused to a folded protein. For example, NGT fused to superfolder green fluorescent protein (NGTsfGFP) formed materials that emitted green fluorescence in blue light, while NGT fused to NanoLuc luciferase (NGTnL) formed materials that emitted blue light in the presence of the chemical substrate furimazine. Oscillatory rheology established the materials as weak viscoelastic gels that can undergo shear-thinning and self-healing. Gel formation could be disrupted by mutating the asparagines in NGT to glutamines, introducing a chaotropic agent, or modifying the asparagines in NGT with glucose, suggesting a role for hydrogen bonds involving asparagine in supramolecular network formation. A mixture of soluble NGTsfGFP and NGTnL formed a multifunctional gel at reduced temperature that demonstrated bioluminescence resonance energy transfer between the nL and sfGFP domains in the presence of furimazine. Collectively, these data establish NGT as a temperature-responsive polypeptide tag that can be used to create functional biomaterials from soluble fusion proteins synthesized by cell-based hosts.