Zwitterionic‐Coated “Stealth” Nanoparticles for Biomedical Applications: Recent Advances in Countering Biomolecular Corona Formation and Uptake by the Mononuclear Phagocyte System

Nanoparticles represent highly promising platforms for the development of imaging and therapeutic agents, including those that can either be detected via more than one imaging technique (multi‐modal imaging agents) or used for both diagnosis and therapy (theranostics). A major obstacle to their medical application and translation to the clinic, however, is the fact that many accumulate in the liver and spleen as a result of opsonization and scavenging by the mononuclear phagocyte system. This focused review summarizes recent efforts to develop zwitterionic‐coatings to counter this issue and render nanoparticles more biocompatible. Such coatings have been found to greatly reduce the rate and/or extent of non‐specific adsorption of proteins and lipids to the nanoparticle surface, thereby inhibiting production of the “biomolecular corona” that is proposed to be a universal feature of nanoparticles within a biological environment. Additionally, in vivo studies have demonstrated that larger‐sized nanoparticles with a zwitterionic coating have extended circulatory lifetimes, while those with hydrodynamic diameters of ≤5 nm exhibit small‐molecule‐like pharmacokinetics, remaining sufficiently small to pass through the fenestrae and slit pores during glomerular filtration within the kidneys, and enabling efficient excretion via the urine. The larger particles represent ideal candidates for use as blood pool imaging agents, whilst the small ones provide a highly promising platform for the future development of theranostics with reduced side effect profiles and superior dose delivery and image contrast capabilities.     

Au/NaYF4 : Yb,Er Binary Superparticles: Synthesis and Optical Properties

Colloidal superparticles (SPs) are nanoparticle (NP) assemblies in the form of colloidal particles. Assembling nanoscopic objects into mesoscopic or macroscopic composite architectures allows for the bottom-up fabrication of functional nanomaterials. In this study, a method for single-step self-assembly synthesis of Au/NaYF₄ : Yb,Er SPs was developed using oil-in-water (O/W) microemulsions to simultaneously encapsulate gold nanoparticles (AuNPs) and NaYF₄ : Yb,Er upconversion nanoparticles (UCNPs) via evaporation at room temperature. The synthesized Au/NaYF₄ : Yb,Er SPs possess good dispersibility and stability. When the number of AuNPs added is increased, the SPs exhibit decreased upconversion luminescence, which can be ascribed to the Förster resonance energy transfer (FRET) from the NaYF₄ : Yb,Er UCNPs to the AuNPs. Time-resolved measurements of the green emission further confirm the existence of a new decay route corresponding to the FRET process. Our research provides a facile and versatile strategy for the synthesis of novel multifunctional nanocomposites with tunable upconversion luminescence properties, which can be of great significance in biological applications.     

Two‐Dimensional Nanomaterials for Biomedical Applications: Emerging Trends and Future Prospects

Two‐dimensional (2D) nanomaterials are ultrathin nanomaterials with a high degree of anisotropy and chemical functionality. Research on 2D nanomaterials is still in its infancy, with the majority of research focusing on elucidating unique material characteristics and few reports focusing on biomedical applications of 2D nanomaterials. Nevertheless, recent rapid advances in 2D nanomaterials have raised important and exciting questions about their interactions with biological moieties. 2D nanoparticles such as carbon‐based 2D materials, silicate clays, transition metal dichalcogenides (TMDs), and transition metal oxides (TMOs) provide enhanced physical, chemical, and biological functionality owing to their uniform shapes, high surface‐to‐volume ratios, and surface charge. Here, we focus on state‐of‐the‐art biomedical applications of 2D nanomaterials as well as recent developments that are shaping this emerging field. Specifically, we describe the unique characteristics that make 2D nanoparticles so valuable, as well as the biocompatibility framework that has been investigated so far. Finally, to both capture the growing trend of 2D nanomaterials for biomedical applications and to identify promising new research directions, we provide a critical evaluation of potential applications of recently developed 2D nanomaterials.     

A critical review of bioceramics for magnetic hyperthermia

Magnetic hyperthermia (HT) using biocompatible ceramics is a ground-breaking, competent, and safe thermo-therapeutic strategy for cancer treatment. The magnetic properties of bioceramics, along with their structure and synthesis parameters, are responsible for the controlled heating of malignant tumors and are the key to clinical success. After providing a brief overview of magnetism and its significance in biomedicine, this review deals with materials selection and synthesis methods of bioceramics/glasses used for HT. Relevant research carried out on promising bioceramics for magnetic HT, with a focus on their size, shape, surface functionalization, magnetic field parameters, and in vitro/in vivo properties to optimize cancer therapy, is also discussed. Recent progress in magnetic HT combined with chemotherapy and phototherapy is especially highlighted, with the aim to provide interdisciplinary knowledge to advance further the applications of bioceramics in this field.     

金属酞菁/卟啉分子电催化CO2还原的研究进展

大气中日益增加的CO₂浓度导致了气候变化等环境问题。将CO₂催化转化为有价值的化学品具有重要意义。利用太阳能、风能等可再生能源产生的电能,通过电化学方法将CO₂还原转化为有价值的碳基化合物是最具有应用前景的方式。分子催化剂具有明确的结构和清晰的活性位点,可实现基于机理的性能优化。综述了近年来金属酞菁/卟啉分子在电催化CO₂还原为CO的实验和理论方面的最新研究进展。首先,介绍了金属酞菁/卟啉分子电催化CO₂还原为CO的详细机理。然后,重点介绍了如何通过分子分散和配体修饰提升金属酞菁/卟啉分子电催化CO₂还原为CO的活性和选择性。最后,讨论了金属酞菁/卟啉分子电催化CO₂还原存在的挑战及其可能的解决方案。     

酚醛基炭气凝胶的研究进展

炭气凝胶是一种多孔纳米炭材料,具有低密度、高孔隙率、高比表面积、优异的导电性和良好的成型性能等优点,是炭材料研究的热点和重要方向。本文旨在通过阐明酚醛基炭气凝胶的制备原料和制备工艺的发展过程,从而突出未来酚醛基炭气凝胶的发展方向。基于此,本文首先重点介绍了酚醛基炭气凝胶的制备方法,主要包括溶胶-凝胶化、干燥以及炭化过程三个最主要的步骤;进而详述了以三种不同的前体,即间苯二酚、苯酚、生物质单宁/木质素分别制备酚醛基炭气凝胶的方法及其优缺点;接下来对酚醛基炭气凝胶作为吸附材料（气体吸附/液体吸附）的吸附量以及在电化学储能以及其他领域的应用进行了综述;最后对酚醛基炭气凝胶未来的研究方向和发展前景进行了总结和展望。文章指出,传统的以间苯二酚为原料辅以超临界干燥的方法制备的酚醛基炭气凝胶,原料成本较高,反应条件苛刻,实际生产应用受限;以苯酚取代间苯二酚,亦或是采用冷冻干燥等方法改进其制备工艺,可以大幅度降低原料和生产成本;但未来的发展方向和重点将是绿色、可再生的生物质原料（单宁、木质素、腰果酚等）及复合气凝胶材料的研发。因此,酚醛基炭气凝胶在未来的发展还需要进一步改进其制备工艺和方法,拓宽其原料来源,从而提高性能,扩大应用领域。     

纳米材料在抗高温钻井液中的应用进展

纳米材料具有尺寸较小、热稳定性强等性质,使其可作为钻井液处理剂来提高钻井液的抗高温性能。抗高温钻井液用纳米材料一般采用将材料纳米化或将纳米材料与聚合物复合制得,大致可分为无机纳米材料、聚合物纳米球和纳米复合材料三类。此外,对纳米材料进行结构优化可提高其热稳定性和分散性,用于封堵岩层中纳米孔隙、降低钻井液滤失量、改善钻井液流变性和提高钻井液抗温能力。本文简要阐述高温对钻井液性能的影响,分析纳米材料在钻井液中的作用,重点介绍不同类型纳米材料在抗高温（≥150℃）钻井液中的应用,尤其是对钻井液流变性能和降滤失效果的影响。最后指出纳米材料作为钻井液处理剂未来发展应向着环保、合成工艺简化和室内与现场研究相结合等方向突破。     

Runx1 Messenger RNA Delivered by Polyplex Nanomicelles Alleviate Spinal Disc Hydration Loss in a Rat Disc Degeneration Model

Vertebral disc degenerative disease (DDD) affects millions of people worldwide and is a critical factor leading to low back and neck pain and consequent disability. Currently, no strategy has addressed curing DDD from fundamental aspects, because the pathological mechanism leading to DDD is still controversial. One possible mechanism points to the homeostatic status of extracellular matrix (ECM) anabolism, and catabolism in the disc may play a vital role in the disease’s progression. If the damaged disc receives an abundant amount of cartilage, anabolic factors may stimulate the residual cells in the damaged disc to secrete the ECM and mitigate the degeneration process. To examine this hypothesis, a cartilage anabolic factor, Runx1, was expressed by mRNA through a sophisticated polyamine-based PEG-polyplex nanomicelle delivery system in the damaged disc in a rat model. The mRNA medicine and polyamine carrier have favorable safety characteristics and biocompatibility for regenerative medicine. The endocytosis of mRNA-loaded polyplex nanomicelles in vitro, mRNA delivery efficacy, hydration content, disc shrinkage, and ECM in the disc in vivo were also examined. The data revealed that the mRNA-loaded polyplex nanomicelle was promptly engulfed by cellular late endosome, then spread into the cytosol homogeneously at a rate of less than 20 min post-administration of the mRNA medicine. The mRNA expression persisted for at least 6-days post-injection in vivo. Furthermore, the Runx1 mRNA delivered by polyplex nanomicelles increased hydration content by ≈43% in the punctured disc at 4-weeks post-injection (wpi) compared with naked Runx1 mRNA administration. Meanwhile, the disc space and ECM production were also significantly ameliorated in the polyplex nanomicelle group. This study demonstrated that anabolic factor administration by polyplex nanomicelle-protected mRNA medicine, such as Runx1, plays a key role in alleviating the progress of DDD, which is an imbalance scenario of disc metabolism. This platform could be further developed as a promising strategy applied to regenerative medicine.     

Photodynamic Therapy and Multi-Modality Imaging of Up-Conversion Nanomaterial Doped with AuNPs

Two key concerns exist in contemporary cancer chemotherapy in clinic: limited therapeutic efficiency and substantial side effects in patients. In recent years, researchers have been investigating a revolutionary cancer treatment technique, and photodynamic therapy (PDT) has been proposed by many scholars. A drug for photodynamic cancer treatment was synthesized using the hydrothermal method, which has a high efficiency to release reactive oxygen species (ROS). It may also be utilized as a clear multi-modality bioimaging platform for photoacoustic imaging (PAI) due to its photothermal effect, computed tomography (CT), and magnetic resonance imaging (MRI). When compared to single-modality imaging, multi-modality imaging delivers far more thorough and precise details for cancer diagnosis. Furthermore, Au-doped up-conversion nanoparticles (UCNPs) have an exceptionally high luminous intensity. The Au-doped UCNPs, in particular, are non-toxic to tissues without laser at an 808 nm wavelength, endowing the as-prepared medications with outstanding therapeutic efficacy but exceptionally low side effects. These findings may encourage fresh effective imaging-guided approaches to meet the goal of photodynamic cancer therapy to be created.