Latest ArticlesExosomes have attracted widespread interest due to their inherent advantages in tumor diagnosis and treatment monitoring. However, it is still a big challenge for highly sensitive and specific detection of exosome in real complexed samples. Herein, a molecular recognition triggered aptazyme cascade strategy was developed for ultrasensitive detection of cancer exosomes in clinical serum samples. In this design, one target exosome could capture a large quantity of aptazymes for the first-step signal amplification. And then the captured aptazyme was activated and recycled to release the fluorophore-abelled substrate strand for a cascaded signal amplification. Notably, the activation of aptazyme only occurs when it has bound with target exosome, ensuring a low background. The experimental results show that the limit of detection (LOD) and the limit of quantification (LOQ) are 3.5×103 particles/μL and 1.7×104 particles/μL, respectively, which is comparable to the results of most existed fluorescence-based exosome probes. Moreover, this assay possesses high specificity to distinguish exosomes derived from other cell lines. Furthermore, this fluorescence probe was utilized in cancer patient and healthy serum samples successfully, suggesting its great potential for clinical diagnosis and biological studies.
Since the discovery of left-handed G-quadruplex (L-G4) structure formed by natural DNA, there has been a growing interest in its potential functions. This study utilised it to catalyse enantioselective Diels-Alder reactions, considering its different optical rotation compared to an ordinary G4. It was determined that when L-G4 was used with a combination of copper(Ⅱ) ions, there was a good enantioselectivity (-52% ee) without further addition of ligands. When further consideration was given by adding G4 ligands, G4 was further stabilised, even obtaining a better enantioselectivity (up to -80% ee). Moreover, when using ligands that have regulatory effects on G4, the ee value can be adjusted. In this work, a minimal left-handed G4 was reported. A follow-up study was also conducted, which recovers that the minimal left-handed G4 remains its catalytic effect and enantioselectivity, but is not so effective as the former case. This indicates that a complete G4 structure is relatively conducive to chiral catalysis.
Maximizing adsorption and catalytic active sites and promoting the photo-excited charge separation are two key factors to achieve excellent photocatalytic performance. In this study, we report a sol-gel synthesis approach to obtain non-metal doped TiO2 with sponge-like structure and surface-phase junctions all at once. While doping of carbon and nitrogen shifted the activation wavelength to the visible-light region, the innovative use of perchloric acid as a pore-making agent led to the formation of three-dimensional lamellar and porous structure with surface-phase junctions. High surface area with catalytic active sites rendered by the sponge-like structure and surface-phase junctions contributed to the much improved photocatalytic degradation efficiency toward rhodamine B, tetracycline and Disperse Red 60 with excellent reusability and stability. The improved generation and separation efficiency of the photo-induced charge carriers of the as-prepared TiO2 were supported by electrochemical impedance measurements and transient photocurrent responses. This method could also be applied to other photocatalysts to achieve structural alteration and element doping simultaneously.
Quaternary ammonium salts (QASs) are excellent candidates for treating stubborn bacterial infections caused by biofilms due to their high sterilization efficiency and potential inhibition of the development of drug resistance. However, the inherent toxicity of QASs, including cytotoxicity, protein absorption and hemolysis, severely limits their applications in vivo. Herein, a charge-convertible quaternary ammonium salt-based micelle (QAS-SL@CM) was constructed by co-assembly of two amphiphiles with opposite charges and shell cross-linking strategy. The toxicity of the QAS-SL@CM could be greatly reduced towards human cells contrast to the corresponding QASs. By response to the acidic environment at infection sites, the surface charge of QAS-SL@CM could be immediately changed to positive and then target to negatively charged bacteria. Furthermore, β-thiopropionate bonds on QAS-SL@CM could also be disintegrated under acid environment to release QASs to kill bacteria. Importantly, the QAS-SL@CM showed significant therapeutic effect in mice subcutaneous abscesses models without interference with normal cells. Therefore, a surface adaptive micelle constructed by charge-convertible strategy has been developed to overcome the cytotoxicity of QASs, and could intelligently respond to the microenvironment of infected wound for in vivo infection therapy, which shows promising application in clinic.
The last few decades have witnessed the emergence of a very large variety of engineered nanomaterials. However, it is far from to meet the growing clinical demand. Actually, nature itself is an excellent nanotechnologist, and provides us with a range of wonderful materials, from inorganic particles found in non-life bodies to biofilms, like platelets, erythrocyte membranes, produced by many bacteria or cells. These nanomaterials are entirely natural, and not surprisingly, there is a growing interest in the development of natural nanoproducts. Native components-inspired biomaterials have gained considerable attention owing to their safety and functions. In this study, egg white was developed as drug carrier to load PTX by a green and simple one-pot method, and systematic characterization was completed. The results indicated that PTX@EW NPs possess excellent biocompatibility, enhanced tumor targeting capability, effectively reducing the toxic side effects of PTX. The obviously enhanced antitumor effect further confirmed EW was a highly prospective biomaterial in the nano-carrier industry.
In the past few years, photo-crosslinkable hydrogels have drawn a great attention in tissue engineering applications due to their high biocompatibility and extracellular matrix (ECM)-like structure. They can be easily biofabricated through exposure of a photosensitive system composed of photo-crosslinkable hydrogels, photo-initiators and other compounds such as cells and therapeutic molecules, to ultraviolet or visible light. With the development of biofabrication methods, many researchers studied the biological applications of photo-crosslinkable hydrogels in tissue engineering, such as vascular, wound dressing and bone engineering. This review highlights the biomaterials for photo-crosslinkable hydrogels, biofabrication techniques and their biological applications in tissue engineering. Meanwhile, the challenges and prospects of photo-crosslinkable hydrogels are discussed as well.
Due to their high specificity and affinity towards various targets, along with other unique advantages such as stability and low cost, aptamers are widely applied in analytical techniques. A typical aptamer-based electrochemical biosensor is composed of a aptamer as the biological recognition element and transducer converting the biologic interaction into electrical signals for the quantitative measurement of targets. Improvement of the sensitivity of a biosensor is significantly important in order to achieve the detection of biomolecules with low abundance, and different amplification strategies have been explored. The strategies either employ nanomaterials such as gold nanoparticles to construct electrodes which can transfer the biological reactions more efficiently, or attempt to obtain enhanced signal through multi-labeled carriers or utilize enzyme mimics to catalyze redox cycling. This review discusses recent advances in signal amplification methods and their applications. Critical assessment of each method is also considered.
Antimalarial chemotherapies endowed with effectiveness against drug-resistant parasites and good safety are urgently required in clinical. Our previous research revealed that clinical phase Ⅱ antitumor drug Quisinostat was a promising antimalarial prototype by inhibiting the activity of Plasmodium falciparum (P. falciparum) histone deacetylase (PfHDAC). Herein, 30 novel spirocyclic linker derivatives were designed and synthesized based on Quisinostat as lead compound, and then their antimalarial activities and cytotoxicity were systematically evaluated. Among them, compounds 8 and 27 could effectively eliminate wild-type and multi-drug resistant P. falciparum parasites, and display weakened cytotoxicity and good metabolic stability. Western blot assay demonstrated that they could inhibit PfHDAC activity like Quisinostat. In addition, both 8 and 27 showed certain antimalarial efficacy in rodent malaria model, and the animal toxicity of 8 was significantly improved compared with Quisinostat. Overall, 8 and 27 were structurally novel PfHDAC inhibitors and provided prospective prototype for further antimalarial drug research.
The carbon nanotubes (CNTs) as the emerging materials for organic pollutant removal have gradually become a burgeoning research field. Herein, a mini-review of CNTs-based materials currently studies for organic pollutant elimination is presented. This review summarizes the preparation methods of CNTs-based materials. CNTs-based materials can be used as adsorbents to remove organic pollutants in wastewater. The adsorption mechanisms mainly include surface diffusion, pore diffusion and adsorption reaction. Most importantly, an in-depth overview of CNTs-based materials currently available in advanced oxidation processes (AOPs) applications for wastewater treatment is proposed. CNTs-based materials can catalyze different oxidants (e.g., hydrogen peroxide (H2O2), persulfates (PMS/PDS), ozone (O3) and ferrate/permanganate (Fe(VI)/Mn(VII)) to generate more reactive oxygen species (ROS) for organic pollutant elimination. Moreover, the possible reaction mechanisms of removing organic pollutants by CNTs-based materials are summarized systematically and discussed in detail. Finally, application potential and future research directions of CNTs-based materials in the environmental remediation field are proposed.
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