Fluoride-Free Synthesis of 2D Titanium Carbide (MXenes) Assisted by scCO2 -Based Ternary Solution.

2D MXene-Ti3 C2 Tx holds great promise in various electronic applications, especially for electromagnetic interference (EMI) shielding devices and supercapacitors. Ti3 C2 Tx synthesis typically involves the use of hazardous fluorine-containing chemicals that can result in the formation of inert fluoride functional groups on the surface of Ti3 C2 Tx , severely degrading its properties and posing a threat to the performance of electron transfer among electrical devices. Herein, a supercritical carbon dioxide-based ternary solution (scCO2 /DMSO/HCl) to produce fluoride-free Ti3 C2 Tx in mild conditions (via 0.5 m HCl, 20 MPa, 32 °C) is reported. The fluorine-free Ti3 C2 Tx films electrode presents an excellent gravimetric capacitance of 320 F g-1 at 2 mV s-1 in 1 m H2 SO4 . Besides, it is demonstrated that fluorine-free Ti3 C2 Tx films exhibit outstanding EMI shielding efficiency of 53.12 dB at 2.5 µm thickness. The findings offer a mild and practical approach to producing fluoride-free Ti3 C2 Tx and open opportunities for exploring MXenes' potential applications in various fields.

Biosensing of Cysteine through the Induction of Oxygen Vacancies in a Cu/Zr Heterostructure Prepared by Supercritical Antisolvent Technique.

There has been a growing emphasis on facile preparation of binary heterogeneous composite materials. Leveraging the eco-friendly efficiency of supercritical CO2 technology, we achieved precise control over the influencing factors of mass transfer, enabling the accurate modulation of the resulting product morphology and properties. In the current study, CuxO/ZrOy composite materials were prepared using this technology and calcined to obtain electrode materials for the detection of cysteine (Cys). Essential comprehensive characterization techniques were employed to elucidate the heterojunction. The resulting electrode demonstrated a linear response to Cys within a concentration range of 0.5 nM to 1 µM, featuring a high sensitivity of 1035 µA·cm-2·µM-1 and a low detection limit of 97.3 nM. Thus, establishing a novel avenue for nonenzyme-based electrochemical sensors tailored for biologically active Cys detection through the implementation of a heterogeneous structure.

Observing the Evolution of Metal Oxides in Liquids.

Metal oxides with diverse compositions and structures have garnered considerable interest from researchers in various reactions, which benefits from transmission electron microscopy (TEM) in determining their morphologies, phase, structural and chemical information. Recent breakthroughs have made liquid-phase TEM a promising imaging platform for tracking the dynamic structure, morphology, and composition evolution of metal oxides in solution under work conditions. Herein, this review introduces the recent advances in liquid cells, especially closed liquid cell chips. Subsequently, the recent progress including particle growth, phase transformation, self-assembly, core-shell nanostructure growth, and chemical etching are introduced. With the late technical advances in TEM and liquid cells, liquid-phase TEM is used to characterize many fundamental processes of metal oxides for CO2 reduction and water-splitting reactions. Finally, the outlook and challenges in this research field are discussed. It is believed this compilation inspires and stimulates more efforts in developing and utilizing in situ liquid-phase TEM for metal oxides at the atomic scale for different applications.

Nanoarchitectured prototypes of mesoporous silica nanoparticles for innovative biomedical applications.

Despite exceptional morphological and physicochemical attributes, mesoporous silica nanoparticles (MSNs) are often employed as carriers or vectors. Moreover, these conventional MSNs often suffer from various limitations in biomedicine, such as reduced drug encapsulation efficacy, deprived compatibility, and poor degradability, resulting in poor therapeutic outcomes. To address these limitations, several modifications have been corroborated to fabricating hierarchically-engineered MSNs in terms of tuning the pore sizes, modifying the surfaces, and engineering of siliceous networks. Interestingly, the further advancements of engineered MSNs lead to the generation of highly complex and nature-mimicking structures, such as Janus-type, multi-podal, and flower-like architectures, as well as streamlined tadpole-like nanomotors. In this review, we present explicit discussions relevant to these advanced hierarchical architectures in different fields of biomedicine, including drug delivery, bioimaging, tissue engineering, and miscellaneous applications, such as photoluminescence, artificial enzymes, peptide enrichment, DNA detection, and biosensing, among others. Initially, we give a brief overview of diverse, innovative stimuli-responsive (pH, light, ultrasound, and thermos)- and targeted drug delivery strategies, along with discussions on recent advancements in cancer immune therapy and applicability of advanced MSNs in other ailments related to cardiac, vascular, and nervous systems, as well as diabetes. Then, we provide initiatives taken so far in clinical translation of various silica-based materials and their scope towards clinical translation. Finally, we summarize the review with interesting perspectives on lessons learned in exploring the biomedical applications of advanced MSNs and further requirements to be explored.

Three-Dimensional Bioprinting of Decellularized Extracellular Matrix-Based Bioinks for Tissue Engineering.

Three-dimensional (3D) bioprinting is one of the most promising additive manufacturing technologies for fabricating various biomimetic architectures of tissues and organs. In this context, the bioink, a critical element for biofabrication, is a mixture of biomaterials and living cells used in 3D printing to create cell-laden structures. Recently, decellularized extracellular matrix (dECM)-based bioinks derived from natural tissues have garnered enormous attention from researchers due to their unique and complex biochemical properties. This review initially presents the details of the natural ECM and its role in cell growth and metabolism. Further, we briefly emphasize the commonly used decellularization treatment procedures and subsequent evaluations for the quality control of the dECM. In addition, we summarize some of the common bioink preparation strategies, the 3D bioprinting approaches, and the applicability of 3D-printed dECM bioinks to tissue engineering. Finally, we present some of the challenges in this field and the prospects for future development.

Hollow Tobacco Mosaic Virus Coat Protein Assisted Self-Assembly of One-Dimensional Nanoarchitectures.

Herein, an efficient strategy to fabricate well-organized one-dimensional (1D) inorganic nanostructures is demonstrated by utilizing the hollow tobacco mosaic virus coat protein (TMVCP) as a restrictive template. Considering the advantages of the unique hollow structure and the dynamic self-assembly attribute of TMVCP, foreign nano-objects are successfully encapsulated and conveniently assembled into highly organized 1D chainlike structures in the cavity of the TMVCP multimer (TMV disk). Different kinds of functional nanoparticles, such as gold nanoparticles (AuNPs) and silver sulfide quantum dots (Ag2S QDs), are used to demonstrate the successful construction of ordered 1D nanochains in high yields. Notably, binary nanochains of such different kinds of nanoparticles are also constructed through co-assembling the TMV disk-coated AuNPs and Ag2S QDs. Further, the TMV-assisted AuNP nanochains are grown into the 1D nanowires through in situ Au deposition owing to the spatial confinement of the TMVCP cavity. Together, our findings indicate that the TMV-assisted self-assembly approach, resulting in higher yields and better controllability over the other reported studies based on directly mineralizing the metal architectures in the TMV nanorods, provides enormous potential toward the fabrication of highly complex hybrid-metal nanostructures.

Role of supercritical carbon dioxide (scCO2) in fabrication of inorganic-based materials: a green and unique route.

In recent times, the supercritical carbon dioxide (scCO2) process has attracted increasing attention in fabricating diverse materials due to the attractive features of environmentally benign nature and economically promising character. Owing to these unique characteristics and high-penetrability, as well as diffusivity conditions of scCO2, this high-pressure technology, with mild operation conditions, cost-effective, and non-toxic, among others, is often applied to fabricate various organic and inorganic-based materials, resulting in the unique crystal architectures (amorphous, crystalline, and heterojunction), tunable architectures (nanoparticles, nanosheets, and aerogels) for diverse applications. In this review, we give an emphasis on the fabrication of various inorganic-based materials, highlighting the recent research on the driving factors for improving the quality of fabrication in scCO2, procedures for production and dispersion in scCO2, as well as common indicators utilized to assess quality and processing ability of materials. Next, we highlight the effects of specific properties of scCO2 towards synthesizing the highly functional inorganic-based nanomaterials. Finally, we summarize this compilation with interesting perspectives, aiming to arouse a more comprehensive utilization of scCO2 to broaden the horizon in exploring the green/eco-friendly processing of such versatile inorganic-based materials. Together, we firmly believe that this compilation endeavors to disclose the latent capability and universal prevalence of scCO2 in the synthesis and processing of inorganic-based materials.

Dual Functional Modification of Alkaline Amino Acids Induces the Self-Assembly of Cylinder-Like Tobacco Mosaic Virus Coat Proteins into Gear-Like Architectures.

Herein, the assembly of 3D uniform gear-like architectures is demonstrated with a tobacco mosaic virus (TMV) disk as a building block. In this context, the intrinsic behavior of the TMV disk that promotes its assembly into nanotubes is altered by a synergistic effect of dual functional modifications at the 53rd arginine mutation and the introduction of lysine groups in the periphery at 1st and 158th positions of the TMV disk, which results in the formation of 3D gear-like superstructures. Therein, the 53rd arginine moiety significantly strengthens the linkage between TMV disks in the alkaline environment through hydrogen bond interactions. The charge of lysine-modified lateral surfaces is partially neutralized in the alkaline solution, which induces the TMV disk to form a gear-like architecture to maintain its structural stability by exploiting the electrostatic repulsion between neighboring TMV disks. This study not only provides explicit evidence regarding the molecular-level understanding of how the modification of site-specific amino acid affects the assembly of resultant superstructures but also encourages the fabrication of functional protein-based nanoarchitectures.

Highly Porous Microcarriers for Minimally Invasive In Situ Skeletal Muscle Cell Delivery.

Microscale cell carriers have recently garnered enormous interest in repairing tissue defects by avoiding substantial open surgeries using implants for tissue regeneration. In this study, the highly open porous microspheres (HOPMs) are fabricated using a microfluidic technique for harboring proliferating skeletal myoblasts and evaluating their feasibility toward cell delivery application in situ. These biocompatible HOPMs with particle sizes of 280-370 µm possess open pores of 10-80 µm and interconnected paths. Such structure of the HOPMs conveniently provide a favorable microenvironment, where the cells are closely arranged in elongated shapes with the deposited extracellular matrix, facilitating cell adhesion and proliferation, as well as augmented myogenic differentiation. Furthermore, in vivo results in mice confirm improved cell retention and vascularization, as well as partial myoblast differentiation. These modular cell-laden microcarriers potentially allow for in situ tissue construction after minimally invasive delivery providing a convenient means for regeneration medicine.

Multi-Organs-on-Chips: Towards Long-Term Biomedical Investigations.

With advantageous features such as minimizing the cost, time, and sample size requirements, organ-on-a-chip (OOC) systems have garnered enormous interest from researchers for their ability for real-time monitoring of physical parameters by mimicking the in vivo microenvironment and the precise responses of xenobiotics, i.e., drug efficacy and toxicity over conventional two-dimensional (2D) and three-dimensional (3D) cell cultures, as well as animal models. Recent advancements of OOC systems have evidenced the fabrication of 'multi-organ-on-chip' (MOC) models, which connect separated organ chambers together to resemble an ideal pharmacokinetic and pharmacodynamic (PK-PD) model for monitoring the complex interactions between multiple organs and the resultant dynamic responses of multiple organs to pharmaceutical compounds. Numerous varieties of MOC systems have been proposed, mainly focusing on the construction of these multi-organ models, while there are only few studies on how to realize continual, automated, and stable testing, which still remains a significant challenge in the development process of MOCs. Herein, this review emphasizes the recent advancements in realizing long-term testing of MOCs to promote their capability for real-time monitoring of multi-organ interactions and chronic cellular reactions more accurately and steadily over the available chip models. Efforts in this field are still ongoing for better performance in the assessment of preclinical attributes for a new chemical entity. Further, we give a brief overview on the various biomedical applications of long-term testing in MOCs, including several proposed applications and their potential utilization in the future. Finally, we summarize with perspectives.

Transition Metal Oxide-Decorated MXenes as Drugless Nanoarchitectonics for Enriched Nanocatalytic Chemodynamic Treatment.

Despite their unique characteristics, 2D MXenes with sole photothermal conversion ability are required to explore their superfluous abilities in biomedicine. The small-molecule-based chemotherapeutics suffer from various shortcomings of time-consuming and expensiveness concerning theoretical and performance (preclinical/clinical) checks. This study demonstrates the fabrication of Ti3C2 MXene nanosheets (TC-MX NSs) and subsequent decoration with transition metal oxides, that is, copper oxide (Cu2O/MX, CO-MX NCs) as drugless nanoarchitectonics for synergistic photothermal (PTT)-chemodynamic therapeutic (CDT) efficacies. Initially, the monolayer/few-layered TC-MX NSs are prepared using the chemical etching-assisted ultrasonic exfoliation method and then deposited with Cu2O nanoconstructs using the in situ reduction method. Further, the photothermal ablation under near-infrared (NIR)-II laser irradiation shows PTT effects of CO-MX NCs. The deposited Cu2O on TC-MX NSs facilitates the release of copper (Cu+) ions in the acidic microenvironment intracellularly for Fenton-like reaction-assisted CDT effects and enriched PTT effects synergistically. Mechanistically, these deadly free radicals intracellularly imbalance the glutathione (GSH) levels and result in mitochondrial dysfunction, inducing apoptosis of 4T1 cells. Finally, the in vivo investigations in BALB/c mice confirm the substantial ablation of breast carcinoma. Together, these findings demonstrate the potential synergistic PTT-CDT effects of the designed CO-MX NCs as drugless nanoarchitectonics against breast carcinoma.

NIR-II light triggered burst-release cascade nanoreactor for precise cancer chemotherapy.

The current strategy of co-delivering copper ions and disulfiram (DSF) to generate cytotoxic CuET faces limitations in achieving rapid and substantial CuET production, specifically in tumor lesions. To overcome this challenge, we introduce a novel burst-release cascade reactor composed of phase change materials (PCMs) encapsulating ultrasmall Cu2-xSe nanoparticles (NPs) and DSF (DSF/Cu2-xSe@PCM). Once triggered by second near-infrared (NIR-II) light irradiation, the reactor swiftly releases Cu2-xSe NPs and DSF, enabling catalytic reactions that lead to the rapid and massive production of Cu2-xSe-ET complexes, thereby achieving in situ chemotherapy. The mechanism of the burst reaction is due to the unique properties of ultrasmall Cu2-xSe NPs, including their small size, multiple defects, and high surface activity. These characteristics allow DSF to be directly reduced and chelated on the surface defect sites of Cu2-xSe, forming Cu2-xSe-ET complexes without the need for copper ion release. Additionally, Cu2-xSe-ET has demonstrated a similar (to CuET) anti-tumor activity through increased autophagy, but with even greater potency due to its unique two-dimensional-like structure. The light-triggered cascade of interlocking reactions, coupled with in situ explosive generation of tumor-suppressive substances mediated by the size and valence of Cu2-xSe, presents a promising approach for the development of innovative nanoplatforms in the field of precise tumor chemotherapy.

Protein-guided biomimetic nanomaterials: a versatile theranostic nanoplatform for biomedical applications.

Over the years, bioinspired mineralization-based approaches have been applied to synthesize multifunctional organic-inorganic nanocomposites. These nanocomposites can address the growing demands of modern biomedical applications. Proteins, serving as vital biological templates, play a pivotal role in the nucleation and growth processes of various organic-inorganic nanocomposites. Protein-mineralized nanomaterials (PMNMs) have attracted significant interest from researchers due to their facile and convenient preparation, strong physiological activity, stability, impressive biocompatibility, and biodegradability. Nevertheless, few comprehensive reviews have expounded on the progress of these nanomaterials in biomedicine. This article systematically reviews the principles and strategies for constructing nanomaterials using protein-directed biomineralization and biomimetic mineralization techniques. Subsequently, we focus on their recent applications in the biomedical field, encompassing areas such as bioimaging, as well as anti-tumor, anti-bacterial, and anti-inflammatory therapies. Furthermore, we discuss the challenges encountered in practical applications of these materials and explore their potential in future applications. This review aspired to catalyze the continued development of these bioinspired nanomaterials in drug development and clinical diagnosis, ultimately contributing to the fields of precision medicine and translational medicine.

Preparation of methotrexate-loaded, large, highly-porous PLLA microspheres by a high-voltage electrostatic antisolvent process.

A high-voltage (10 kV) electrostatic antisolvent process was used to prepare methotrexate (MTX)-loaded, large, highly-porous poly-L-lactide (PLLA) microspheres. MTX solution in dimethyl sulfoxide (DMSO) and PLLA solution in dichloromethane (DCM) were homogeneously mixed, and then ammonium bicarbonate (AB) aqueous solution was added. The mixed solution was emulsified by ultrasonication with Pluronic F127 (PF127) as an emulsion stabilizer. The emulsion was electrosprayed by the specific high-voltage apparatus and dropped into a 100 mL of ethanol, which acted as an antisolvent for the solute and extracted DMSO and DCM, causing the co-precipitation of PLLA and MTX, thus forming microspheres with AB aqueous micro-droplets uniformly inlaid. The obtained MTX-PLLA microspheres were subsequently lyophilized to obtain large, highly-porous MTX-PLLA microspheres, which exhibited an identifiable spherical shape and a rough surface furnished with open pores, with a mean particle size of 25.0 µm, mass median aerodynamic diameter of 3.1 ± 0.2 µm, fine-particle fraction of 57.1 ± 1.6 %, and porosity of 81.8 %; furthermore, they offered a sustained release of MTX. X-ray diffraction and Fourier transform-infrared spectra revealed that no crystallinity or alteration of chemical structure occurred during the high-voltage electrostatic antisolvent process, which in this study was proved to have great potential for preparing highly-porous drug-loaded polymer microspheres for use in pulmonary drug delivery.

Sonodynamic therapy-based nanoplatforms for combating bacterial infections.

The rapid spread and uncontrollable evolution of antibiotic-resistant bacteria have already become urgent global to treat bacterial infections. Sonodynamic therapy (SDT), a noninvasive and effective therapeutic strategy, has broadened the way toward dealing with antibiotic-resistant bacteria and biofilms, which base on ultrasound (US) with sonosensitizer. Sonosensitizer, based on small organic molecules or inorganic nanoparticles, is essential to the SDT process. Thus, it is meaningful to design a sonosensitizer-loaded nanoplatform and synthesize the nanoplatform with an efficient SDT effect. In this review, we initially summarize the probable SDT-based antibacterial mechanisms and systematically discuss the current advancement in different SDT-based nanoplatform (including nanoplatform for organic small-molecule sonosensitizer delivery and nanoplatform as sonosensitizer) for bacterial infection therapy. In addition, the biomedical applications of SDT-involved multifunctional nanoplatforms are also discussed. We believe the innovative SDT-based nanoplatforms would become a highly efficient next-generation noninvasive therapeutic tool for combating bacterial infection.

Hybrid nanoarchitectonics of molybdenum dioxide (MoO2) and doxorubicin (DOX) for synergistic chemo-photothermal-based breast carcinoma therapy.

Cancer has emerged as one of the severe ailments due to the uncontrolled proliferation rate of cells, accounting for millions of deaths annually. Despite the availability of various treatment strategies, including surgical interventions, radiation, and chemotherapy, tremendous advancements in the past two decades of research have evidenced the generation of different nanotherapeutic designs toward providing synergistic therapy. In this study, we demonstrate the assembly of a versatile nanoplatform based on the hyaluronic acid (HA)-coated molybdenum dioxide (MoO2) assemblies to act against breast carcinoma. The hydrothermal approach-assisted MoO2 constructs are immobilized with doxorubicin (DOX) molecules on the surface. Further, these MoO2-DOX hybrids are encapsulated with the HA polymeric framework. Furthermore, the versatile nanocomposites of HA-coated MoO2-DOX hybrids are systematically characterized using various characterization techniques, and explored biocompatibility in the mouse fibroblasts (L929 cell line), as well as synergistic photothermal (808-nm laser irradiation for 10 min, 1 W/cm2) and chemotherapeutic properties against breast carcinoma (4T1 cells). Finally, the mechanistic views concerning the apoptosis rate are explored using the JC-1 assay to measure the intracellular mitochondrial membrane potential (MMP) levels. In conclusion, these findings indicated excellent photothermal and chemotherapeutic efficacies, exploring the enormous potential of MoO2 composites against breast cancer.

Immune-regulating camouflaged nanoplatforms: A promising strategy to improve cancer nano-immunotherapy.

Although nano-immunotherapy has advanced dramatically in recent times, there remain two significant hurdles related to immune systems in cancer treatment, such as (namely) inevitable immune elimination of nanoplatforms and severely immunosuppressive microenvironment with low immunogenicity, hampering the performance of nanomedicines. To address these issues, several immune-regulating camouflaged nanocomposites have emerged as prevailing strategies due to their unique characteristics and specific functionalities. In this review, we emphasize the composition, performances, and mechanisms of various immune-regulating camouflaged nanoplatforms, including polymer-coated, cell membrane-camouflaged, and exosome-based nanoplatforms to evade the immune clearance of nanoplatforms or upregulate the immune function against the tumor. Further, we discuss the applications of these immune-regulating camouflaged nanoplatforms in directly boosting cancer immunotherapy and some immunogenic cell death-inducing immunotherapeutic modalities, such as chemotherapy, photothermal therapy, and reactive oxygen species-mediated immunotherapies, highlighting the current progress and recent advancements. Finally, we conclude the article with interesting perspectives, suggesting future tendencies of these innovative camouflaged constructs towards their translation pipeline.

[Research progress in co-delivery of gene and chemotherapy drugs with cationic liposome carrier for cancer therapy].

Despite recent advances in conventional therapeutic approaches for cancer, the efficacy of chemotherapy for cancer is limited due to the drug resistance and toxic side effects during treatment. To overcome drug resistance, higher doses of the toxic chemotherapy drugs are frequently administered, thus leading to even severe adverse side effects, which have limited their clinical application. Cationic liposome as a novel non-viral carrier for co-delivery of gene and chemotherapy drugs in cancer gene therapy has already attracted more and more attention in recent years. Most importantly, this combined strategy can generate a significant synergistic effect, which can silence the related gene expression and increase the concentration of the intracellular chemotherapy drugs. This approach allows the use of a much lower dose of the chemotherapy drugs to achieve same therapeutic effect, which may have the potential for overcoming some major limitations of the conventional chemotherapy. In conclusion, co-delivery of gene and chemotherapy drugs with cationic liposome delivery system will play a vital role in the future and especially could be a promising clinical treatment for drug-resistant tumors.

Upconversion Luminescence via Anion Exchange in Perovskite Quantum Dots for Anticounterfeiting Inkjet Printing.

Lanthanide-doped upconversion nanoparticles (UCNPs) and cesium lead halide perovskite quantum dots (PeQDs) are highly compatible with each other: UCNPs produce anti-Stokes upconversion luminescence (UCL) under near-infrared (NIR) excitation and the emissive profiles of PeQDs can be conveniently tuned by varying the halide composition ratio. Therefore, in this study, UCNPs and PeQDs are mixed together, producing colorful UCL under 980 nm laser excitation. In addition, ZnI2 is used to vary the halide composition ratio of PeQDs and manipulate UCL in situ, thus adding more flexibility in UCL regulation. Finally, based on the above-mentioned discussion, a double-encrypted anticounterfeiting pattern is generated via sequentially printing ZnI2 solution and UCNP suspension on an A4 paper. Using PeQDs as the decrypting reagent, under the NIR excitation and decryption channel, the hidden information can be fully decrypted. The combination of UCNPs and PeQDs greatly expands the upconversion possibility, offers more feasibility in UCL regulation, and further promotes the practical applications.

3D Printing of Ultrathin MXene toward Tough and Thermally Resistant Nanocomposites.

Liquid crystal display (LCD)-based 3D printing, a facile and cost-effective manufacturing technique, is often applied when fabricating objects with porcelain structures using photosensitive resins (PSRs). Currently, 3D printed constructions are typically used as models for demonstration purposes rather than industrial applications because of their poor performance. In this study, we prepared nanocomposites by incorporating Ti3C2 MXene nanosheets to enhance the overall characteristics of a PSR, including mechanical properties and thermal resistance. Notably, the designed nanocomposites showed optimum performance at an MXene loading of 0.5% w/w. The mechanical properties of the designed nanocomposites confirmed the enhanced ultimate tensile and flexural strengths (by 32.1% and 42.7%, respectively), at 0.5% w/w MXene loading. Moreover, the incorporated MXene presented no substantial influence on the toughness of the PSR. The glass transition and thermal degradation temperatures at 5% weight loss increased by 7.4 and 10.6 °C, respectively, resulting predominantly from the hydrogen bonding between the PSR and MXene. Together, the experimental results indicate that the designed PSR/MXene nanocomposites are expected to replace pristine resins for LCD printing in various practical applications.