Latest ArticlesIn recent years, multicolor cascade supramolecular assemblies with controllable topological morphology have become a research hotspot due to their wide application in light-emitting materials, cell imaging and other fields. Herein, several kinds of macrocycles including cucurbiturils, calixarene and cyclodextrins are used as building blocks to construct fluorescent assemblies with anthryl-conjugated phenylpyridine (G), wherein cucurbit[8]uril (CB[8]) and G can form nanowires at a stoichiometric ratio of n: n through host-guest encapsulation to form a non-covalent heterodimer. Significantly, the macrocycle confinement effect drastically enhances the fluorescence emission of G and emission peak generated bathochromic shift from 500 nm to 600 nm. When the supramolecular polymer is further assembled with amphiphilic calix[4]arene (SC4A8), the fluorescence emission of G⊂CB[8] further increases to 1.4 times, accompanied by the morphological transformation from linear structure to nanorod structure. Subsequently, a very small amount of dye Cy5 is added to the assembly solution as an energy receptor, and the negatively charged G⊂CB[8]@SC4A8 system is regarded as an energy donor. The efficient energy transfer process enables near-infrared (NIR) emission at 675 nm with 71% energy transfer efficiency (ΦET) at a donor/receptor ratio of 100:1. Finally, the cascade supramolecular assembly has been successfully applied to targeted imaging in the nucleus of HeLa and A549 cancer cells.
As a hydrolase, chymotrypsin (CHT) is involved in many physiological activities, and its abnormal activity is closely related to diabetes, pancreatic fibrosis, chronic pancreatitis and pancreatic cancer. In this work, an innovative long-wavelength emission fluorescent probe TCF-CHT was designed and synthesized for the high specificity detection of CHT, which utilized TCF-OH and a mimetic peptide substrate 4-bromobutyryl as chromogenic group and recognition group, respectively. TCF-CHT exhibited excellent selectivity and eye-catching sensitivity (8.91 ng/mL) towards CHT, "off-on" long-wavelength emission at 670 nm and large Stokes shift (140 nm). Furthermore, the successful fulfillment and perfect performance in imaging endogenous CHT in complex organisms (P815 cells, HepG2 cells, zebrafish and tumor-bearing mice) verified its potential as a powerful tool for the recognition of CHT in complicated biological environments.
Activated pancreatic stellate cells (PSCs) are the main source of collagen layer deposition and the key target in pancreatic fibrosis. However, no effective treatment specific to pancreatic fibrosis clinically, owing to the drug accumulation blocked by the collagen barrier and thus it is difficult to inhibit activated PSCs precisely. Herein, a PSCs-targeting nano-system based on “nanodrill” strategy (LA-PC) was designed to enhance the accumulation of all-trans retinoic acid (ATRA) in PSCs, relying on the platelet-derived growth factor receptor beta (PDGFRβ)-targeting peptide (pPB: C*SRNLIDC*) and collagenase (Col). After being injected into fibrotic mice via tail vein, the Col modified on LA-PC can remove the excess collagen layer, and the drug delivery efficiency through pPB targeting peptide was more than 5 times higher than that of free ATRA, as well as the degree of fibrosis significantly reduced. Notably, this nano-system effectively inhibited platelet-derived growth factor subunit B (PDGF-BB)/PDGFRβ axis on PSCs via a down-regulated extracellular signal-regulated protein kinase (ERK) pathway, and accordingly reduced the level of PDGF-BB. Thus, the smart platform provided a promising strategy for the treatment of pancreatic fibrosis to achieve the precise regulation of PSCs.
The topology of conjugated macrocycles had significant impacts on their photo-physical and photo-chemical properties. Herein, a series of π-conjugated macrocycles with diverse topology were synthesized via intramolecular McMurry coupling. Their chemical structure and macrocyclic topology were unambiguously confirmed via NMR, MALDI-TOF mass spectra, crystal analysis and scanning tunneling microscopy (STM). Depending on the structural topology and structural rigidity, these cyclic compounds display obviously distinctive emission behavior and photochemical reactions in the solution and in the solid state. Monocyclic phenylene vinylene macrocycle (denoted as MST) exhibiting aggregation-induced emission behavior, was more vulnerable to photo-cyclization in solution and triplet sensitizer promoted photo-dimerization due to lower strain and more flourishing intramolecular motions. After UV light irradiation, relatively more flexible MST could yield the anti-dimer via triplet excimer on the HOPG surface confirmed by STM investigation. By contrast, highly constrained bicyclic analogue (named as DMTPE) with central tetraphenylethene core, displayed high emission quantum yields of 68% both in solution and in the solid state, and was relatively inert to photochemical reactions and yield syn-dimer on the surface via singlet excimer involved [2 + 2] photo-dimerization. Based on the solution-mediated photo-polymerization of MST moiety, multicyclic porous carbon-rich ribbon connected with four-membered ring was successfully constructed and validated via STM imaging.
Reactive oxygen species (ROSs) in Fenton process are of great importance in treating contaminants in wastewater. It is crucial to understand their chemical properties, formation, and reaction mechanisms with contaminants. This review summarizes the reactive oxygen species in Fenton process, including hydroxyl radical (•OH), superoxide radical (O2•−), singlet oxygen (1O2), hydroperoxyl radical (HO2•), and high-valent iron. •OH shows a trend to react with chemistry groups with abundant electrons through H-atom abstraction, radical adduct formation and single electron transfer. Electron transfer is discovered to be an important pathway when 1O2 degrades organic pollutants. Ring-opening and β-scission are proposed to be the possible ways of 1O2 to certain contaminants. Proton abstraction, nucleophilic substitution, and single electron transfer are proposed to explain how O2•− degrade pollutants. As the conjugated acid of O2•−, radical adduct formation and H-atom abstraction are reported for the reaction mechanisms of hydroperoxyl radical. High-valent iron in Fenton, namely Fe(Ⅳ), reacts with certain pollutants via single- or two-electron transfer. This review is important for researchers to understand the ROSs produced in Fenton and how they react with pollutants.
Antibiotics, as widely used antibacterial drug, exist in various environmental media. Antibiotic residues can affect biological metabolism and lead to bacterial resistance and the formation of antibiotic-resistance genes, posing a threat to human health and ecological safety. Establishing efficient detection methods for antibiotics and antibiotic-resistance genes has great environmental significance. Fluorescence detection methods, due to their fast response, high sensitivity and specificity, and low-cost, are widely used in chemical and biological sensing. This review first summarizes the pre-treatment methods for different types of environmental samples, and then focuses on the recent advances of fluorescence methods for the detection of antibiotics and antibiotic-resistance genes. Finally, main challenges and future research directions of fluorescence methods for antibiotic and antibiotic-resistance genes detection are discussed. This review highlights the promising prospect of fluorescence methods in-situ detection and monitoring of antibiotics and antibiotic-resistance genes, and provides guidance for the construction of overall risk assessment system of environmental media.
Bioelectronics have gained substantial research attention owing to their potential applications in health monitoring and diagnose, and greatly promoted the development of biomedicine. Recently, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) hydrogels have arose as a promising candidate for the next-generation bioelectronic interface due to its high-conductivity, versatility, flexibility and biocompatibility. In this review, we highlight the recent advances of PEDOT:PSS hydrogels, including the gelation methods and modification strategies, and summarize their wide applications in different type of sensors and tissue engineering in detail. We expect that this work will provide valuable information regarding the functionalizations and applications of PEDOT:PSS hydrogels.
Epilepsy, as a chronic neurological disease of the brain, is closely related to oxidative stress, and the peroxynitrite (ONOO−) significantly rise up in this event. Therefore, ONOO− is considered as a potential biomarker for early prediction of epilepsy. However, some potential diagnostic reagents for epilepsy are hindered by the blood-brain barrier (BBB). Meanwhile, “drug repurposing” is attracting a growing interest. Edaravone (EDA), as a first-line drug in the clinical treatment of cerebral ischemia, plays antioxidant roles in scavenging free radicals, promising potential antiepileptic activity. Thus, it is imperative to develop fluorescent probes for monitoring ONOO− fluctuations in the epileptic brain. Hence, we proposed a novel fluorescent probe with the thiocarbonate as the promising recognition unit for ONOO− and dicyanoisophorone derivative as the fluorophore. Moreover, by the “three-in-one” strategy, the introduction of trifluoromethyl into DCI-ONOO-3 can extend the emission wavelength of the fluorophore, shorten the response and increase lipophilicity. Consequently, DCI-ONOO-3 was used for monitoring ONOO− fluxes in brain of epileptic mice and evaluating the antiepileptic efficacy of EDA. It opens up a new way for the design of BBB permeable fluorescent probes, and provides a convincing new method for the diagnosis and treatment of epilepsy.
Sonodynamic therapy (SDT) exhibits promising clinical applications in cancer treatment owing to its advantages, including ultrasonic cavitation effect, mechanical effect, and deep tissue penetration. Titanium dioxide (TiO2) nanomaterials, recognized as excellent sonosensitizers, have been extensively studied in cancer SDT. This review first outlines the mechanism of TiO2-based SDT, then systematically discusses the regulation of TiO2 sonosensitivity, covering aspects such as morphology, particle size, element doping, defect engineering, heterojunction structure, and interactions with the tumor microenvironment. Furthermore, the review generalizes ultrasound-responsive TiO2-based therapeutic modalities for tumor treatment, including SDT, SDT combined with chemotherapy, chemodynamic therapy, photothermal therapy, immunotherapy, and treatment visualization. Finally, the review navigates the ongoing challenges and prospects in TiO2-based cancer SDT.
DNA-based hydrogels are exceptional materials for biological applications because of their numerous advantages such as biodegradability, biocompatibility, hydrophilicity, super absorbency, porosity, and swelling. Among these advantages, the ability of DNA-based hydrogels to respond to specific physical and chemical triggers and undergo reversible phase transitions has garnered significant attention in the fields of disease diagnosis (biosensors) and treatment (drug delivery). This article focuses on the recent advancements in the research of DNA-based hydrogels and discusses the different types of these hydrogels, the synthetic methods, their unique properties, and their applications in biosensors and drug delivery. The types of DNA hydrogels are categorized based on their building blocks, and the process of synthesis as well as the unique characteristics of DNA-based hydrogels are described. Then, DNA-based responsive hydrogels utilized as intelligent materials for the development of biosensors are reviewed. Furthermore, this article also presents the current status of DNA-based responsive hydrogels in drug delivery for cancer treatment, wound healing, and other therapeutic applications. Ultimately, this paper discusses the current challenges in expanding the practical application of DNA-based hydrogels.
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