Myocardial injury as one of the severe complications leads to the increasing morbidity and mortality in patients with sepsis. Recent studies reported that reactive oxygen species (ROS)-mediated ferroptosis plays a critical role in the development of heart diseases. Therefore, we hypothesized that anti-ferroptosis agent might be a novel potential therapeutic strategy for sepsis-induced cardiac injury. Herein, we demonstrated that a small biocompatible and MRI-visible melanin nanoparticles (MMPP) improves myocardial function by inhibiting ROS-related ferroptosis signaling pathway. In LPS-induced murine sepsis model, after a single dose intravenously injection of MMPP treatment, MMPP markedly alleviated the myocardial injury including cardiac function and heart structure disorder through suppressing iron-accumulation induced ferroptosis. In vitro, MMPP inhibited cardiomyocyte death by attenuating oxidative stress, inflammation and maintaining mitochondrial homeostasis. Collectively, our findings demonstrated that MMPP protected heart against sepsis-induced myocardial injury via inhibiting ferroptosis and inflammation, which might be a novel therapeutic approach in future.

Exosomes affect the initiation and progression of cancers. In the tumor microenvironment, not only cancer cells, but also fibroblasts and immunocytes secrete exosomes. Exosomes act as a communicator between cells by transferring different cargos and microRNAs (miRNAs). Drug resistance is one of the critical factors affecting therapeutic effect in the course of cancer treatment. The currently known mechanisms of drug resistance include drug efflux, alterations in drug metabolism, DNA damage repair, alterations of energy programming, cancer stem cells and epigenetic changes. Many studies have shown that miRNA carried by exosomes is closely associated with the development of drug resistance mediated by the above-mentioned mechanisms. This review article will discuss how exosomal miRNAs regulate the drug resistance.

Developing stable photoelectrochemistry (PEC) glucose biosensors with high sensitivity and a low detection limit is highly desirable in the biosensor field. Herein, a highly sensitive and stable enzymatic glucose PEC biosensor is rationally designed and fabricated using a TiO₂NTs/Au/Pt/GOx electrode. First, we prepared one-dimensional TiO₂ nanotube arrays which could realize the orthogonalization of the light-incident direction and the carrier diffusion direction via anodization. Subsequently, we used the method of photoassisted deposition for anchoring Pt nanoparticles on TiO₂NTs after electrodepositing Au nanoparticles. Among them, Au nanoparticles promote light absorption via the surface plasmon resonance effect and the separation of photogenerated carriers through forming a Schottky junction. Moreover, the Pt nanoparticles on the electrode surface can react with hydrogen peroxide (H₂O₂) generated from glucose (Glu) oxidation by glucose oxidase (GOx), accelerating the electron-transfer process during glucose oxidation and greatly improving the sensitivity of the glucose biosensor. As a result, TiO₂NTs/Au/Pt/GOx exhibited excellent PEC performance, achieving a high sensitivity of 81.93 μA mM^–1 cm^–2 and a low detection limit (1.39 μM), far exceeding the performance of TiO₂NTs/M/GOx (M = Au, Pt). Therefore, the introduction of Pt nanoparticles as active substances to promote enzymatic reactions is important for designing high-performance enzyme biosensors.

Signal‐amplified imaging of microRNAs (miRNAs) is a promising strategy at the single‐cell level because liquid biopsy fails to reflect real‐time dynamic miRNA levels. However, the internalization pathways for available conventional vectors predominantly involve endo‐lysosomes, showing nonideal cytoplasmic delivery efficiency. In this study, size‐controlled 9‐tile nanoarrays are designed and constructed by integrating catalytic hairpin assembly (CHA) with DNA tile self‐assembly technology to achieve caveolae‐mediated endocytosis for the amplified imaging of miRNAs in a complex intracellular environment. Compared with classical CHA, the 9‐tile nanoarrays possess high sensitivity and specificity for miRNAs, achieve excellent internalization efficiency by caveolar endocytosis, bypassing lysosomal traps, and exhibit more powerful signal‐amplified imaging of intracellular miRNAs. Because of their excellent safety, physiological stability, and highly efficient cytoplasmic delivery, the 9‐tile nanoarrays can realize real‐time amplified monitoring of miRNAs in various tumor and identical cells of different periods, and imaging effects are consistent with the actual expression levels of miRNAs, ultimately demonstrating their feasibility and capacity. This strategy provides a high‐potential delivery pathway for cell imaging and targeted delivery, simultaneously offering a meaningful reference for the application of DNA tile self‐assembly technology in relevant fundamental research and medical diagnostics.

The development of a photoelectrochemical (PEC) sensor for the sensitive and rapid detection of glucose is highly desirable. In PEC enzyme sensors, inhibition of the charge recombination of electrode materials is an efficient technique, and detection in visible light can prevent enzyme inactivation due to ultraviolet irradiation. In this study, a visible light-driven PEC enzyme biosensor was proposed, using CDs/branched TiO₂ (B-TiO₂) as the photoactive material and glucose oxidase (GOx) as the identification element. The CDs/B-TiO₂ composites were produced via a facile hydrothermal method. Carbon dots (CDs) can not only act as photosensitizers but also inhibit photogenerated electron and hole recombination of B-TiO₂. Under visible light, electrons in the carbon dots flowed to B-TiO₂ and further to the counter electrode through the external circuit. In the presence of glucose and dissolved oxygen, H₂O₂ generated through the catalysis of GOx could consume electrons in B-TiO₂, causing a decrease in photocurrent intensity. Ascorbic acid was added to ensure the stability of the CDs during the test. Based on the variation of the photocurrent response, the CDs/B-TiO₂/GOx biosensor presented a good sensing performance of glucose in visible light, its detection range was from 0 to 9.00 mM, and the detection limit was 0.0430 mM.