Near-infrared light-heatable platinum nanozyme for synergistic bacterial inhibition.

The development of non-antibiotic strategies for bacterial disinfection is of great clinical importance. Among recently developed different antimicrobial strategies, nanomaterial-mediated approaches, especially the photothermal way and reactive oxygen species (ROS)-generating method, show many significant advantages. Although promising, the clinical application of nanomaterials is still limited, owing to the potential biosafety issues. Further improvement of the antimicrobial activity to reduce the usage, and thus reduce the potential risk, is an important way to increase the clinical applicability of antibacterial nanomaterials. In this paper, an antimicrobial nanostructure with both an excellent photothermal effect and peroxidase-like activity was constructed to achieve efficient synergistic antimicrobial activity. The obtained nano-antimicrobial agent (ZIF-8@PDA@Pt) can not only efficiently catalyze the production of ROS from H2O2 to cause damage to bacteria but also convert the photon energy of near-infrared light into thermal energy to kill bacteria, and the two synergistic effects induced in a highly efficient antimicrobial activity. This study not only offers a new nanomaterial with efficient antibacterial activity but also proposes a new idea for constructing synergistic antibacterial properties.

Nanoparticles-mediated ion channels manipulation: From their membrane interactions to bioapplications.

Ion channels are transmembrane proteins ubiquitously expressed in all cells that control various ions (e.g. Na+, K+, Ca2+ and Cl- etc) crossing cellular plasma membrane, which play critical roles in physiological processes including regulating signal transduction, cell proliferation as well as excitatory cell excitation and conduction. Abnormal ion channel function is usually associated with dysfunctions and many diseases, such as neurodegenerative disorders, ophthalmic diseases, pulmonary diseases and even cancers. The precise regulation of ion channels not only helps to decipher physiological and pathological processes, but also is expected to become cutting-edge means for disease treatment. Recently, nanoparticles-mediated ion channel manipulation emerges as a highly promising way to meet the increasing requirements with respect to their simple, efficient, precise, spatiotemporally controllable and non-invasive regulation in biomedicine and other research frontiers. Thanks the advantages of their unique properties, nanoparticles can not only directly block the pore sites or kinetics of ion channels through their tiny size effect, and perturb active voltage-gated ion channel by their charged surface, but they can also act as antennas to conduct or enhance external physical stimuli to achieve spatiotemporal, precise and efficient regulation of various ion channel activities (e.g. light-, mechanical-, and temperature-gated ion channels etc). So far, nanoparticles-mediated ion channel regulation has shown potential prospects in many biomedical fields at the interfaces of neuro- and cardiovascular modulation, physiological function regeneration and tumor therapy et al. Towards such important fields, in this typical review, we specifically outline the latest studies of different types of ion channels and their activities relevant to the diseases. In addition, the different types of stimulation responsive nanoparticles, their interaction modes and targeting strategies towards the plasma membrane ion channels will be systematically summarized. More importantly, the ion channel regulatory methods mediated by functional nanoparticles and their bioapplications associated with physiological modulation and therapeutic development will be discussed. Last but not least, current challenges and future perspectives in this field will be covered as well.

A Retrospective Study of Puncture and Drainage for Primary Brainstem Hemorrhage With the Assistance of a Surgical Robot.

BACKGROUND: Whether primary brainstem hemorrhage (PBH) should be treated with a conservative treatment or with surgical intervention (such as craniotomy, puncture, and drainage) is still controversial. The aim of this study was to assess the feasibility and safety of puncture and drainage for PBH with the assistance of a surgical robot. PATIENTS AND METHODS: A total of 53 patients diagnosed with PBH were included in this study. They were divided into surgical and nonsurgical groups. All patients in the surgical group underwent puncture and drainage of PBH assisted with surgical robots at Beijing Jingmei General Hospital from June 2017 to January 2021. We evaluated this technology with radiographic and clinical results. RESULTS: Postoperative computed tomography showed that all the drainage catheters had been pushed to the target point, which had been designated before the operation. After the operation, the hematoma was reduced by an average of 3.7 mL. None of the patients experienced serious surgery-related complications. Clinical follow-up revealed that 2 patients could not be followed-up, 8 died, and the rest were in disability or in a vegetative state. CONCLUSIONS: It may be safe, feasible, and effective to complete the puncture and drainage of PBH with the assistance of a surgical robot. This technique has fewer complications than the traditional puncture method and has high accuracy. It may be more suitable for patients with a hematoma volume of 5 to 10 mL in PBH. The amount of hematoma volume >10 mL may be associated with poor postoperative prognosis. However, high-quality cohorts or case-control studies are needed to verify the effect in this study.

A metal-organic framework nanocomposite with oxidation and near-infrared light cascade response for bacterial photothermal inactivation.

Photothermal treatment is an effective and precise bacterial disinfection method that can reduce the occurrence of bacterial drug resistance. However, most conventional photothermal treatment strategies have the problem that the photothermal response range does not match the infection area. Herein, a metal-organic framework (MOF) nanocomposite responding to the oxidation state of the bacterial infection microenvironment was constructed for near-infrared (NIR) photothermal bacterial inactivation. In this strategy, the MOF was used as a nanocarrier to load tetramethylbenzidine (TMB) and horseradish peroxidase (HPR). The high oxidation state of the bacterial infection microenvironment can trigger the enzyme-catalyzed reaction of the nanocomposite, thereby generating oxidation products with the NIR photothermal effect for bacterial disinfection. The synthesis and characterization of the nanocomposite, oxidation state (H2O2) response effect, photothermal properties, and antibacterial activities were systematically studied. This study provides a new idea for building a precision treatment system for bacterial infection.

Screening of multifunctional fruit carbon dots for fluorescent labeling and sensing in living immune cells and zebrafishes.

Nine kinds of carbon dots (CDs) were synthesized by using fruits with different varieties as carbon sources; meanwhile, the fluorescence characteristics, quantum yield, and response ability to different metal ions and free radicals were systematically studied. These CDs showed similar excitation and emission spectral ranges (λex ≈ 345 nm, λem ≈ 435 nm), but very different fluorescence quantum yield (QY), in which orange and cantaloupe CDs have the highest QY around 0.25 and green plum CDs showed the lowest quantum yield around 0.1. Interestingly, the fluorescence of all of these CDs can be significantly quenched by hydroxyl radical (•OH) and iron ion (Fe3+); however, these CDs showed very different response characteristics to other metal ions (e.g., Co2+, Ni2+, Cu2+, Ce3+, Mn2+, Ag+, and Fe2+). Through in-depth analysis, we found some interesting patterns of the influence of carbon sources on the fluorescence characteristics of CDs. Finally, by using white pitaya CDs as fluorescence probe, we realized sensing of Fe3+ and •OH with limits of detection (LOD) of 19.4 µM and 0.7 µM, respectively. Moreover, the CDs were also capable for sensitive detection in immune cells and even in zebrafishes. Our work can provide valuable guidance for the rational design of functional CDs for biological applications.

Protein-Mediated Fluorescence Resonance Energy Transfer (P-FRET) Probe: Fabrication and Hydroxyl Radical Detection.

Fluorescent probes based on fluorescence resonance energy transfer (FRET) are highly promising for diverse bioapplications. The key to constructing FRET probes is to confine the donor and acceptor within a sufficiently close distance. However, the commonly used covalent linkage often requires elaborate design and complex organic synthesis, and sometimes causes changes in the fluorescence properties of the donor and acceptor. Inspired by the binding between small molecules and protein in nature, herein, we propose a protein-mediated strategy to fabricate FRET probe. In such protein-mediated FRET (P-FRET) probe, protein acts as a carrier to simultaneously confine donor and acceptor in its cavity. As a proof of concept, we use bovine serum albumin (BSA) as a model protein, coumarin derivative as a donor and hydroxyl radical (·OH)-responsive dye fluorescein as an acceptor. Through a series of investigations, including binding parameters, fluorescence properties and detection performance, we prove that the construction of P-FRET probe is simple and feasible and the detection is sensitive. Our P-FRET strategy will provide new insights for the design of FRET probes.

A biodegradable and near-infrared light-activatable photothermal nanoconvertor for bacterial inactivation.

The development of biodegradable nanomaterials for near-infrared photothermal antibacterial is of great significance to improve the biosafety of nano-antibacterial strategies in clinical application. In this study, a new nano-antibacterial strategy was developed, in which a biodegradable charge-transfer nanocomplex acted as a high-efficiency near-infrared light-activatable photothermal nanoconvertor. The charge-transfer nanocomplex was synthesized through oxidation-induced self-assembly of 3,3',5,5'-tetramethylbenzidine molecules. This nanocomplex can efficiently convert light energy around 900 nm into heat energy, with a photothermal conversion efficiency of up to 30%. More importantly, the nanocomplex can spontaneously degrade under physiological conditions within 12 hours. Utilizing the photothermal effect of this nanocomplex, both Gram-positive bacteria and Gram-negative bacteria can be inactivated within 2 minutes. In addition, the inactivation mechanism was systematically discussed and the results indicated that the photothermal effect induced bacterial cell membrane damage was probably responsible for the antibacterial effect.

Will the Bacteria Survive in the CeO2 Nanozyme-H2O2 System?

As one of the nanostructures with enzyme-like activity, nanozymes have recently attracted extensive attention for their biomedical applications, especially for bacterial disinfection treatment. Nanozymes with high peroxidase activity are considered to be excellent candidates for building bacterial disinfection systems (nanozyme-H2O2), in which the nanozyme will promote the generation of ROS to kill bacteria based on the decomposition of H2O2. According to this criterion, a cerium oxide nanoparticle (Nanoceria, CeO2, a classical nanozyme with high peroxidase activity)-based nanozyme-H2O2 system would be very efficient for bacterial disinfection. However, CeO2 is a nanozyme with multiple enzyme-like activities. In addition to high peroxidase activity, CeO2 nanozymes also possess high superoxide dismutase activity and antioxidant activity, which can act as a ROS scavenger. Considering the fact that CeO2 nanozymes have both the activity to promote ROS production and the opposite activity for ROS scavenging, it is worth exploring which activity will play the dominating role in the CeO2-H2O2 system, as well as whether it will protect bacteria or produce an antibacterial effect. In this work, we focused on this discussion to unveil the role of CeO2 in the CeO2-H2O2 system, so that it can provide valuable knowledge for the design of a nanozyme-H2O2-based antibacterial system.

Association between sleep duration and rupture of intracranial aneurysms: A single-center retrospective study.

OBJECTIVE: To assess the relationship between sleep duration and risk of rupture of intracranial aneurysms (IAs). METHODS: According to our inclusion and exclusion criteria, 683 patients admitted to Beijing Tiantan Hospital were included in this study. There were 201 patients in the ruptured group and 482 patients in the unruptured group. Sleep duration was divided into three levels: ≥8 h (long), 6-8 h (normal), ≤6 h (short). Correlation between different sleep duration and rupture of IAs was evaluated by univariate and multivariate regression analysis. RESULTS: The results of multivariate analysis demonstrated that there was a statistical difference between sleep duration of ≤6 h and sleep duration ≥8 h (OR = 1.76, CI = [1.08-2.87], p = 0.025). There was no statistically significant difference between the group with sleep duration of 6-8 h and sleep duration of ≥8 h (OR = 1.04, CI = [0.65-1.67], p = 0.857). CONCLUSION: Short sleep duration (≤6 h) may be related to the rupture of intracranial aneurysms. The reason for this correlation is not yet clear. We suspect that it may be caused by a series of physiological changes caused by reduced sleep.

Is smoking a risk factor for bleeding in adult men with cerebral arteriovenous malformations? A single-center regression study from China.

OBJECTIVE: To assess whether smoking increases the risk of bleeding in patients with cerebral arteriovenous malformations (CAVM). MATERIAL AND METHODS: According to our research plan, 385 CAVM patients admitted to Beijing Tiantan Hospital from December 2015 to January 2018 were included in this study, including 210 bleeding patients and 175 non-bleeding patients. We divided patients into three subgroups of current smokers, ex-smokers (those who quit smoking for one year or more) and non-smokers. The relationship between smoking and the risk of CAVM rupture was assessed by univariate and multivariate regression analysis. RESULTS: Multivariate regression analysis showed that there was a statistically significant difference between current smoker and non-smoker (OR = 1.87, p = 0.019). Among the covariates of the multivariate regression analysis, the location, combined with blood flow-related intracranial aneurysms and size were related to the risk of CAVM bleeding. CONCLUSION: Current smoking may increase the risk of CAVM bleeding; however, there was no significant correlation between ex-smoking and CAVM bleeding.