Facile synthesis of Gd/Ru-doped fluorescent carbon dots for fluorescent/MR bimodal imaging and tumor therapy.

Functional metal doping endows fluorescent carbon dots with richer physical and chemical properties, greatly expanding their potential in the biomedical field. Nonetheless, fabricating carbon dots with integrated functionality for diagnostic and therapeutic modalities remains challenging. Herein, we develop a simple strategy to prepare Gd/Ru bimetallic doped fluorescent carbon dots (Gd/Ru-CDs) via a one-step microwave-assisted method with Ru(dcbpy)3Cl2, citric acid, polyethyleneimine, and GdCl3 as precursors. Multiple techniques were employed to characterize the morphology and properties of the obtained carbon dots. The Gd/Ru-CDs are high mono-dispersity, uniform spherical nanoparticles with an average diameter of 4.2 nm. Moreover, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) confirmed the composition and surface properties of the carbon dots. In particular, the successful doping of Gd/Ru enables the carbon dots not only show considerable magnetic resonance imaging (MRI) performance but also obtain better fluorescence (FL) properties, especially in the red emission area. More impressively, it has low cytotoxicity, excellent biocompatibility, and efficient reactive oxygen species (ROS) generation ability, making it an effective imaging-guided tumor treatment reagent. In vivo experiments have revealed that Gd/Ru-CDs can achieve light-induced tumor suppression and non-invasive fluorescence/magnetic resonance bimodal imaging reagents to monitor the treatment process of mouse tumor models. Thus, this simple and efficient carbon dot manufacturing strategy by doping functional metals has expanded avenues for the development and application of multifunctional all-in-one theranostics.

NIR/MRI-Guided Oxygen-Independent Carrier-Free Anti-Tumor Nano-Theranostics.

Imaging-guided photothermal therapy (PTT)/photodynamic therapy (PDT) for cancer treatment are beneficial for precise localization of the malignant lesions and combination of multiple cell killing mechanisms in eradicating stubborn thermal-resistant cancer cells. However, overcoming the adverse impact of tumor hypoxia on PDT efficacy remains a challenge. Here, carrier-free nano-theranostic agents are developed (AIBME@IR780-APM NPs) for magnetic resonance imaging (MRI)-guided synergistic PTT/thermodynamic therapy (TDT). Two IR780 derivatives are synthesized as the subject of nanomedicine to confer the advantages for the nanomedicine, which are by feat of amphiphilic IR780-PEG to enhance the sterical stability and reduce the risk from reticuloendothelial system uptake, and IR780-ATU to chelate Mn2+ for T1 -weighted MRI. Dimethyl 2,2'-azobis(2-methylpropionate) (AIBME), acting as thermally decomposable radical initiators, are further introduced into nanosystems with the purpose of generating highly cytotoxic alkyl radicals upon PTT launched by IR780 under 808 nm laser irradiation. Therefore, the sequentially generated heat and alkyl radicals synergistically induce cell death via synergistic PTT/TDT, ignoring tumor hypoxia. Moreover, these carrier-free nano-theranostic agents present satisfactory biocompatibility, which could be employed as a powerful weapon to hit hypoxic tumors via MRI-guided oxygen-independent PTT and photonic TDT.

Water exchange-assisted versus carbon dioxide-insufflated single-balloon enteroscopy: a randomized controlled trial.

BACKGROUND: Single-balloon enteroscopy (SBE) is a valuable but difficult modality for the diagnosis and treatment of small-bowel disease. The water exchange method has the advantage of facilitating intubation during colonoscopy. Here, we evaluated the effects of water exchange on procedure-related variables related to SBE. METHODS: This randomized controlled trial was conducted in a tertiary-care referral center in China. Patients due for attempted total enteroscopy were randomly allocated to undergo water exchange-assisted (water exchange group) or carbon dioxide-insufflated enteroscopy (CO2 group). All patients were planned to undergo both anterograde and retrograde procedures. The primary outcome was the total enteroscopy rate. Secondary outcomes included the maximal insertion depth, positive findings, procedural time, and adverse events. RESULTS: In total, 110 patients were enrolled, with 55 in each group. Baseline characteristics between the two groups were comparable. Total enteroscopy was achieved in 58.2 % (32/55) of the water exchange group and 36.4 % (20/55) of the control group (P = 0.02). The mean (standard deviation) estimated intubation depth was 521.2 (101.4) cm in the water exchange group and 481.6 (95.2) cm in the CO2 group (P = 0.04). The insertion time was prolonged in the water exchange group compared with the CO2 group (178.9 [45.1] minutes vs. 154.2 [27.6] minutes; P < 0.001). Endoscopic findings and adverse events were comparable between the two groups. CONCLUSIONS: The water exchange method improved the total enteroscopy rate and increased the intubation depth during SBE. The use of water exchange did not increase the complications of enteroscopy.

Synthesis of fluorescent nanoprobe with simultaneous response to intracellular pH and Zn2+ for tumor cell distinguishment.

A novel dual-functional nanoprobe was designed and synthesized by facile assembly of quinoline derivative (PEIQ) and meso-tetra (4-carboxyphenyl) porphine (TCPP) via electrostatic interaction for simultaneous sensing of fluorescence of Zn2+ and pH. Under the single-wavelength excitation at 400 nm, this nanoprobe not only exhibits "OFF-ON" green fluorescence at 512 nm by specific PEIQ-Zn2+ chelation, but also presents red fluorescence enhancement at 654 nm by H+-triggered TCPP release. The nanoprobe demonstrated excellent sensing performance with a good linear range (Zn2+, 1-40 µM; pH, 5.0-8.0), low detection limit (Zn2+, 0.88 µM), and simultaneous response towards Zn2+ and pH in pure aqueous solution within 2 min. More importantly, this dual-functional nanoprobe demonstrates the capability of discerning cancerous cells from normal cells, as evidenced by the fact that cancerous HepG2 cells in tumor microenvironment exhibit substantially higher red fluorescence and significantly lower green fluorescence than normal HL-7702 cells. The simultaneous, real-time fluorescence imaging of multiple analytes in a living system could be significant for cell analysis and tracking, cancer diagnosis, and even fluorescence-guided surgery of tumors.

Fluoxetine ameliorates dysbiosis in a depression model induced by chronic unpredicted mild stress in mice.

Background: Accumulating evidence has shown that neuropsychiatric disorders are associated with gut microbiota through the gut-brain axis. However, the effects of antidepressant treatment on gut microbiota are rarely studied. Here, we investigated whether stress led to gut microbiota changes and whether fluoxetine plays a role in microbiota alteration. Methods: We investigated changes in gut microbiota in a depression model induced by chronic unpredicted mild stress (CUMS) and a restoration model by applying the classic antidepressant drug fluoxetine. Results: We found that stress led to low bacterial diversity, simpler bacterial network, and increased abundance of pathogens, such as Escherichia/Shigella, and conditional pathogens, such as Enterococcus, Vagococcus, and Aerococcus. However, these changes were attenuated by fluoxetine directly and indirectly. Furthermore, the correlation analysis indicated strong correlations between gut microbiota and anxiety- and depression-like behaviors. Conclusions: This study revealed that fluoxetine led to restoration of dysbiosis induced by stress stimulation, which may imply a possible pathway through which one CNS target drug plays its role in reshaping the gut microbiota.

Extracellular versus Intracellular Degradation of Nanostructured Silica Particles.

Silica nanoparticles appear as promising drug carriers for intracellular delivery. However, the mechanisms by which they are degraded within cells remain largely unknown. In this context, we have prepared three types of PEGylated fluorescent silica nanoparticles with various internal structures (core-shell biocomposite, multilayered, and hollow mesoporous) and studied their degradation in a buffer, in a culture medium, and in contact with human dermal fibroblasts. All particles were prone to dissolve in solution, leading to an increase of porosity and/or the precipitation of new colloids and eventually fragmentation, with a faster rate in the medium compared to that in the buffer. All particles were also uptaken by the cells without significant cytotoxic effect. Their intracellular degradation occurred faster than in suspension, but following almost similar dissolution mechanisms. These results strongly suggest that in these conditions, silica nanoparticles must be primarily considered as hydrolytically degraded and not biodegraded, a point of importance for their future applications in drug delivery.

Do political connections facilitate or inhibit firms' digital transformation? Evidence from China's A-share private listed companies.

Given the advent of the digital era, digital transformation has become necessary for enterprise development. Political connections are the most important resources for enterprise development in most countries. However, the impact of political connections on corporate digital transformation has yet to be verified. This study uses ERNIE, a large language model, to construct a measurement of corporate digital transformation from the perspective of digital technology application through a textual analysis of the annual reports of A-share privately listed companies from 2008 to 2020 and analyzes the impact of political connections on corporate digital transformation and its mechanism of action. The findings demonstrate that political connections have a significant inhibitory effect on corporate digital transformation. This conclusion still holds after a series of robustness and endogeneity tests. The mechanism analyses demonstrate that political connections primarily affect corporate digital transformation through three mechanisms: weakening risk, inhibiting innovation, and enhancing resource crowding. We theoretically expand the understanding of the economic impact of political connections and provide new ideas for accelerating enterprise digital transformation from the perspective of policy makers.

Clinical features and prognostic factors of duodenal neuroendocrine tumours: A comparative study of ampullary and nonampullary regions.

BACKGROUND: Duodenal neuroendocrine tumours (DNETs) are rare neoplasms. However, the incidence of DNETs has been increasing in recent years, especially as an incidental finding during endoscopic studies. Regrettably, there is no consensus regarding the ideal treatment of DNETs. Even there are few studies on the clinical features and survival analysis of DNETs. AIM: To analyze the clinical characteristics and prognostic factors of patients with duodenal neuroendocrine tumours. METHODS: The clinical data of DNETs diagnosed in the First Affiliated Hospital of Air Force Military Medical University from June 2011 to July 2022 were collected. Neuroendocrine tumours located in the ampulla area of the duodenum were divided into the ampullary region group; neuroendocrine tumours in any part of the duodenum outside the ampullary area were divided into the nonampullary region group. Using a retrospective study, the clinical characteristics of the two groups and risk factors affecting the survival of DNET patients were analysed. RESULTS: Twenty-nine DNET patients were screened. The male to female ratio was 1:1.9, and females comprised the majority. The ampullary region group accounted for 24.1% (7/29), while the nonampullary region group accounted for 75.9% (22/29). When diagnosed, the clinical symptoms of the ampullary region group were mainly abdominal pain (85.7%), while those of the nonampullary region groups were mainly abdominal distension (59.1%). There were differences in the composition of staging of tumours between the two groups (Fisher's exact probability method, P = 0.001), with nonampullary stage II tumours (68.2%) being the main stage (P < 0.05). After the diagnosis of DNETs, the survival rate of the ampullary region group was 14.3% (1/7), which was lower than that of 72.7% (16/22) in the nonampullary region group (Fisher's exact probability method, P = 0.011). The survival time of the ampullary region group was shorter than that of the nonampullary region group (P < 0.000). The median survival time of the ampullary region group was 10.0 months and that of the nonampullary region group was 451.0 months. Multivariate analysis showed that tumours in the ampulla region and no surgical treatment after diagnosis were independent risk factors for the survival of DNET patients (HR = 0.029, 95%CI 0.004-0.199, P < 0.000; HR = 12.609, 95%CI: 2.889-55.037, P = 0.001). Further analysis of nonampullary DNET patients showed that the survival time of patients with a tumour diameter < 2 cm was longer than that of patients with a tumour diameter ≥ 2 cm (t = 7.243, P = 0.048). As of follow-up, 6 patients who died of nonampullary DNETs had a tumour diameter that was ≥ 2 cm, and 3 patients in stage IV had liver metastasis. Patients with a tumour diameter < 2 cm underwent surgical treatment, and all survived after surgery. CONCLUSION: Surgical treatment is a protective factor for prolonging the survival of DNET patients. Compared to DNETs in the ampullary region, patients in the nonampullary region group had a longer survival period. The liver is the organ most susceptible to distant metastasis of nonampullary DNETs.

MRI-guided cell membrane-camouflaged bimetallic coordination nanoplatform for combined tumor phototherapy.

Nanotechnology for tumor diagnosis and optical therapy has attracted widespread interest due to its low toxicity and convenience but is severely limited due to uncontrollable tumor targeting. In this work, homologous cancer cell membrane-camouflaged multifunctional hybrid metal coordination nanoparticles (DRu/Gd@CM) were prepared for MRI-guided photodynamic therapy (PDT) and photothermal therapy (PTT) of tumors. Bimetallic coordination nanoparticles are composed of three functional modules: dopamine, Ru(dcbpy)3Cl2 and GdCl3, which are connected through 1,4-Bis[(1H-imidazole-1-yl)methyl]benzene (BIX). Their morphology can be easily controlled by adjusting the ratio of precursors. Optimistically, the intrinsic properties of the precursors, including the photothermal properties of polydopamine (PDA), the magnetic resonance (MR) response of Gd3+, and the singlet oxygen generation of Ru(dcbpy)3Cl2, are well preserved in the hybrid metal nanoparticles. Furthermore, the targeting of homologous cancer cell membranes enables these coordinated nanoparticles to precisely target tumor cells. The MR imaging capabilities and the combination of PDT and PTT were demonstrated in in vitro experiments. In addition, in vivo experiments indicated that the nanoplatform showed excellent tumor accumulation and therapeutic effects on mice with subcutaneous tumors, and could effectively eliminate tumors within 14 days. Therefore, it expanded the new horizon for the preparation of modular nanoplatform and imaging-guided optical therapy of tumors.

Resistance and virulence genes characteristic of a South Asia Clade (I) Candida auris strain isolated from blood in Beijing.

INTRODUCTION: Candida auris is a globally disseminated invasive ascomycetous yeast, that imposes a substantial burden on healthcare systems. It has been documented to have spread to over 40 countries across six continents, necessitating in-depth comprehension through advanced techniques like Whole-Genome Sequencing. METHOD: This study entailed the isolation and Whole-Genome Sequencing of a fluconazole-resistant C. auris strain (CA01) obtained from a patient's blood in Beijing. Genome analysis was conducted to classify the strain, and molecular docking was performed to understand the impact of mutations on drug resistance. RESULTS: Genome analysis revealed that CA01 belongs to the South Asia Clade (I) and shares the closest genetic relationship with previously reported strains BJCA001 and BJCA002. Notably, unlike BJCA001, CA01 exhibits significant resistance to fluconazole primarily due to the A395T mutation in the ERG11 gene. Molecular docking studies demonstrated that this mutation leads to geometric changes in the active site where fluconazole binds, resulting in decreased binding affinity. Additionally, the present findings have identified several core virulence genes in C. auris, such as RBF1. DISCUSSION: The findings from this study expand the understanding of the genetic diversity and adaptive mechanisms of C. auris within the South Asia Clade (I). The observed fluconazole resistance driven by the ERG11 mutation A395T highlights the need for heightened awareness and adaptation in clinical treatment strategies in China. This study provides critical insights into drug resistance and virulence profiles at a genetic level, which could guide future therapeutic and management strategies for C. auris infections.

Metamaterial Absorbers with Archimedean Tiling Structures: Toward Response and Absorption of Multiband Electromagnetic Waves.

With the continuous development of electromagnetic wave-absorbing materials, the design of artificial structures for electromagnetic absorbers based on the concept of metamaterials is becoming more abundant. However, in the design process, it is difficult to further broaden the effective absorption band due to the limitation that the traditional single-size structure responds to electromagnetic waves only in specific frequency bands. Therefore, in this paper, based on the moth-eye bionic hexagonal structure absorber with antireflection performance, an Archimedean tiling structure is designed to optimize it, and through the introduction of a variety of primitives with large differences in dimensions, a multifrequency band-response mechanism is achieved to enhance the multireflection mechanism, which can effectively broaden the absorption band and improve the wave absorption performance. Ultimately, the moth-eye bionic structure absorber optimized by (3.4.6.4) can achieve an effective absorption of 10.26 GHz at a thickness of 2 mm. This work presents a new idea for the design work of electromagnetic wave-absorbing metamaterials, which has a broad application prospect in the aerospace, electronic information countermeasures, communication, and detection industries.

A facile strategy for the large-scale preparation of starch-based AIE luminescent nanoaggregates via host-guest interactions and their versatile applications.

Luminescent nanomaterials with outstanding optical properties have attracted growing interest due to their widespread applications. However, large-scale fabrication of luminescent nanomaterials with desired properties through a simple and economical process remains challenging. As a renewable natural resource, starch is non-toxic, easily accessible, and inexpensive, making it a popular choice for uses in various biomedical fields. In this work, we present a facile assembly strategy for the fabrication of starch-based luminescent nanoaggregates using starch as the host material and aggregation-induced emission luminogens (AIEgens) as guest molecules. By employing simple procedures under mild conditions, highly luminescent nanoparticles with small sizes, high water dispersibility, and low cytotoxicity are prepared on a large scale. The resulting nano-assemblies demonstrate significantly enhanced fluorescence intensities, reduced susceptibility to photobleaching and low cytotoxicity. These fluorescent supramolecular aggregates can be employed in various application fields, including the fabrication of fluorescent hydrogels, fingerprint detection, cell imaging and in vivo lymphatic system imaging. The methodology developed in this work has immense potential to greatly promote the production of high-quality nanoparticles on the industrial scale, offering a cost-effective solution that can meet the needs of various applications and pave the way for wider implementation of nanotechnology.

Biochemotaxis-Oriented Engineering Bacteria Expressing GLP-1 Enhance Diabetes Therapy by Regulating the Balance of Immune.

Glucagon like peptide-1 (GLP-1) is an effective hypoglycemic drug that can repair the pancreas ß cells and promote insulin secretion. However, GLP-1 has poor stability and lacks of target ability, which makes it difficult to reach the site of action to exert its efficacy. Here, GLP-1-expressing plasmids are introduced into the Escherichia coli Nissle 1917 (EcN) and a lipid membrane is formed through simple self-assembly on its surface, resulting in an oral delivery system (LEG) capable of resisting the harsh environment of the gastrointestinal tract. The system utilizes the chemotactic properties of probiotics to achieve efficient enrichment at the pancreatic site, and protects islet ß cells from destruction by regulating the balance of immune cells. More interestingly, LEG not only continuously produces GLP-1 to restore pancreatic islet ß cell function and secrete insulin to control blood sugar levels, but also regulates the intestinal flora and increases the richness and diversity of probiotics. In mice diabetes models, oral administration of LEG only once every other day has good biosafety and compliance, and achieves long-term control of blood glucose. Therefore, this strategy not only provides an oral delivery platform for pancreatic targeting, but also opens up new avenues for reversing diabetes.

Novel Local-Chiral Metamaterial: Effective Modulation of Amplitude & Phase for Wideband Polarization-Insensitive Absorption.

Metamaterial has received widespread research in the fields of electromagnetic stealth due to its characteristics of strong resonance and flexible designability. However, a lack of a comprehensive understanding of the internal physical mechanism still imposes certain limitations on broadband absorption designs. Hence, this work proposes a new strategy for the broadening of the working frequency band of metamaterial absorbers by constructing local-chiral features to regulate the amplitude and phase information. The absorber consists of staggered cut-wire metal patterns with lumped resistors placed at the center position determined by characteristic mode analysis. Combining the modal significance, equivalent circuit, surface current, electric field distribution, and symmetry model theory, the working mechanism for wideband absorption performance has been analyzed in detail. The experimental results are in good agreement with the simulation results; the absorption rate exceeds 82% in the frequency range of 4.5-11.7 GHz and surpasses about 90% in the frequency range of 4.7-10.8 GHz under transverse electric (TE) or transverse-magnetic (TM) polarizations. Compared to the case without chiral features, the proposed design can achieve a 28% increase in operating bandwidth. The proposed design method is applicable for the optimization of various typical dipole-type metamaterial absorbers and provides a novel strategy for future wideband metamaterial absorption.

Clinical characteristics of acute non-varicose upper gastrointestinal bleeding and the effect of endoscopic hemostasis.

BACKGROUND: Acute non-variceal upper gastrointestinal bleeding (ANVUGIB) constitutes a prevalent emergency within Gastroenterology, encompassing 80%-90% of all gastrointestinal hemorrhage incidents. This condition is distinguished by its abrupt onset, swift progression, and notably elevated mortality rate. AIM: To gather clinical data from patients with ANVUGIB at our hospital in order to elucidate the clinical characteristics specific to our institution and analyze the therapeutic effectiveness of endoscopic hemostasis. METHODS: We retrospectively retrieved the records of 532 patients diagnosed with ANVUGIB by endoscopy at our hospital between March 2021 and March 2023, utilizing our medical record system. Data pertaining to general patient information, etiological factors, disease outcomes, and other relevant variables were meticulously collected and analyzed. RESULTS: Among the 532 patients diagnosed with ANVUGIB, the male-to-female ratio was 2.91:1, with a higher prevalence among males. Notably, 43.6% of patients presented with black stool as their primary complaint, while 27.4% had hematemesis as their initial symptom. Upon admission, 17% of patients exhibited both hematemesis and black stool, while most ANVUGIB patients primarily complained of overt gastrointestinal bleeding. Urgent routine blood examinations at admission revealed that 75.8% of patients had anemia, with 63.4% experiencing moderate to severe anemia, and 1.5% having extremely severe anemia (hemoglobin < 30 g/L). With regard to etiology, 53.2% of patients experienced bleeding without a definitive trigger, 24.2% had a history of using gastric mucosa-irritating medications, 24.2% developed bleeding after alcohol consumption, 2.8% attributed it to improper diet, 1.7% to emotional excitement, and 2.3% to fatigue preceding the bleeding episode. Drug-induced ANVUGIB was more prevalent in the elderly than middle-aged and young individuals, while bleeding due to alcohol consumption showed the opposite trend. Additionally, diet-related bleeding was more common among the young age group compared to the middle-aged group. Gastrointestinal endoscopy identified peptic ulcers as the most frequent cause of ANVUGIB (73.3%), followed by gastrointestinal malignancies (10.9%), acute gastric mucous lesions (9.8%), and androgenic upper gastrointestinal bleeding (1.5%) among inpatients with ANVUGIB. Of the 532 patients with gastrointestinal bleeding, 68 underwent endoscopic hemostasis, resulting in an endoscopic treatment rate of 12.8%, with a high immediate hemostasis success rate of 94.1%. CONCLUSION: ANVUGIB patients exhibit diverse characteristics across different age groups, and endoscopic hemostatic treatments have demonstrated remarkable efficacy.

Coupling gold nanoparticles to silica nanoparticles through disulfide bonds for glutathione detection.

Advances in the controlled assembly of nanoscale building blocks have resulted in functional devices which can find applications in electronics, biomedical imaging, drug delivery etc. In this study, novel covalent nanohybrid materials based upon [Ru(bpy)3](2+)-doped silica nanoparticles (SiNPs) and gold nanoparticles (AuNPs), which could be conditioned as OFF-ON probes for glutathione (GSH) detection, were designed and assembled in sequence, with the disulfide bonds as the bridging elements. The structural and optical properties of the nanohybrid architectures were characterized using transmission electron microscopy, UV-vis spectroscopy and fluorescence spectroscopy, respectively. Zeta potential measurements, x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were employed to monitor the reaction processes of the SiNPs-S-S-COOH and SiNPs-S-S-AuNPs synthesis. It was found that the covalent nanohybrid architectures were fluorescently dark (OFF state), indicating that SiNPs were effectively quenched by AuNPs. The fluorescence of the OFF-ON probe was resumed (ON state) when the bridge of the disulfide bond was cleaved by reducing reagents such as GSH. This work provides a new platform and strategy for GSH detection using covalent nanohybrid materials.

Enterprise resilience to the COVID-19 pandemic: The role of business environment.

Enterprise resilience captures enterprises' ability to survive and develop under uncertainties and shocks. Taking the shock of COVID-19 as an example, this paper employs a unique firm-level national survey dataset collected from a sample of nearly 40,000 Chinese private enterprises in 2020 to systematically explore the relation between local business environment and enterprise resilience. Our estimation results using ordered probit model indicate that favorable business environment can significantly enhance enterprise resilience and mitigate the shock of COVID-19 on firm performance. Mechanism analysis further shows that enterprises under better business environment generally have greater resilience as the result of timely and effective government support, reliable supply of production factors and logistics service, and lower levels of financial constraints. Our study deepens the understanding of the economic consequences of business environment and also sheds a new light on enterprise resilience enhancement.

Bioinspired multiple-degrees-of-freedom responsive metasurface by high-entropy-alloy ribbons with hierarchical nanostructures for electromagnetic wave absorption.

The compound eyes of the dragonfly, Pantala flavescens Fabricius, are covered by micro-scaled ocelli capable of sensing polarized light, an attractive property for radar stealth and counterreconnaissance. In this work, we fabricated biomimetic electromagnetic wave absorption materials (EAMs) by analyzing the covert information identifications of biological systems and focusing on the design of metastructures and microstructures. Several bionic metasurfaces with anisotropic double-V meta atoms made up of (FeCoNiSi8.9Al8.9)C0.2 high-entropy-alloy (HEA) ribbons for multiple-degrees-of-freedom recognition and broadband absorption are presented. The covert phase, amplitude, and angular momentum of electromagnetic waves were controlled and recognized as information by manipulating the rotation angle θ of meta atoms. A vortex wave with a topological charge of 1 was generated to recognize linearly polarization and left- and right-handed circular polarization. In addition, the polarization conversion enhanced absorption. The hierarchical nanostructures of HEA ribbons give rise to suitable electromagnetic loss and a superior impedance match. Finally, inspired by the structure of compound eyes, the designed multilayer metamaterials realized effective absorption (reflection loss (RL) ≤  - 10 dB) within the 4.5-18 GHz regime under 2.8 mm thickness. These materials provide evidence for a new way for integrated EAMs and metamaterials.

MRI-guided dual-responsive anti-tumor nanostructures for synergistic chemo-photothermal therapy and chemodynamic therapy.

Image-guided stimulus-responsive theranostics are beneficial for identifying malignant lesions and integrating multiple cell-killing mechanisms to enhance tumor cell clearance. Herein, an intelligent dual-responsive nanostructure (HSPMH-DOX) was developed for magnetic resonance imaging (MRI)-guided synergistic chemo-photothermal therapy (PTT) and chemodynamic therapy (CDT). The core-shell nanostructure was synthesized by layering polydopamine (PDA), manganese oxide (MnO2), and hyaluronic acid (HA) onto drug-loaded hollow mesoporous silica nanoparticles (HS). The constructed nanoagent has both endogenous and external dual responses. The tumor microenvironment (pH/GSH) can trigger the degradation of gatekeeper (MnO2 and PDA), resulting in the release of anti-tumor drugs, whereas external near-infrared light irradiation can accelerate the degradation process and generate local overheating, resulting in PTT. Notably, MnO2 can not only consume intracellular GSH to enhance CDT but also release Mn2+ for precise localization of tumor tissues using MRI. Both in vitro and in vivo experiments showed that the prepared dual-response nanoagent satisfied biocompatibility, targeting, and the great efficiency of MRI-guided combined therapy. In animal models, combining chemo-PTT and CDT can eradicate tumors in less than two weeks. This work could pave the way for a wide range of stimulus-responsive synergistic theranostic applications, including MRI, chemo-photothermal therapy, and chemodynmic therapy. STATEMENT OF SIGNIFICANCE: Low bioavailability and severe side effects remain the major limitations of conventional cancer chemotherapy. Image-guided combination therapy can alleviate these problems and improve tumor-specific therapy. In the present study, the anticancer drug doxorubicin was encapsulated in a core-shell hollow mesoporous silica nanostructure (HSPMH-DOX), enabling MRI-guided targeted release under both endogenous and external dual stimuli. Moreover, the photothermal and nanoenzymatic effects of nanomedicine can cause local overheating in the tumor and amplify the intracellular CDT effect, accelerating tumor eradication. Systematic evaluations in vitro and in vivo confirmed that nanomedicine enables highly effective MRI-guided synergistic chemo-photothermal and chemodynamic therapy. This work offers a promising therapeutic strategy for precise anti-tumor applications.