Brain glucose is an important biomarker of Alzheimer's disease (AD) and has a high specificity especially for early AD. Activatable magnetic resonance imaging (MRI) contrast agents (CAs) serve as a robust technology in the early diagnosis of many diseases; however, there is a lack of glucose-specific MRI CAs. To address this issue, in this work, we synthesized a novel MRI CA (ZIF-8/GOx@MnO 2 @PEG, ZGMP) that consists of porous zeolitic imidazolate framework-8 (ZIF-8) attached with glucose oxidase (GOx) and modified by MnO 2 and PEG. The cascade reaction of brain glucose with ZGMP could result in the production of Mn(II) and an enhanced MRI signal. An early AD mouse model was constructed through injection of the Aβ42 oligomer into the parenchyma of mice and utilized to verify the brain glucose activated MRI of ZGMP. The results indicated a higher glucose uptake in early AD mice compared to that in normal mice, with an obviously enhanced T 1 WI at the region of interest. This work gets rid of the need for a specific scanning sequence for glucose MRI, paving a convenient way for MRI diagnosis of early AD.
Rheumatoid arthritis (RA) is an autoimmune and inflammatory disease that is so far incurable with long-term health risks. The high doses and frequent administration for the available RA drug always lead to adverse side effects. Aiming at the obstacles to achieving effective RA treatment, we prepared macrophage cell membrane-camouflaged nanoparticles (M-EC), which were assembled from epigallocatechin gallate (EGCG) and cerium(IV) ions. Due to its geometrical similarity to the active metal sites of a natural antioxidant enzyme, the EC possessed a high scavenge efficiency to various types of reactive oxygen species (ROS) and reactive nitrogen species (RNS). The macrophage cell membrane assisted M-EC in escaping from the immune system, being uptaken by inflammatory cells, and specifically binding IL-1β. After tail vein injection to the collagen-induced arthritis (CIA) mouse model, the M-EC accumulated at inflamed joints and effectively repaired the bone erosion and cartilage damage of rheumatoid arthritis by relieving synovial inflammation and cartilage erosion. It is expected that the M-EC can not only pave a new way for designing metal−phenolic networks with better biological activity but also provide a more biocompatible therapeutic strategy for effective treatment of RA.
Patients with triple-negative breast cancer (TNBC) have
dismal
prognoses due to the lack of therapeutic targets and susceptibility
to lymph node (LN) metastasis. Therefore, it is essential to develop
more effective approaches to identify early TNBC tissues and LNs.
In this work, a magnetic resonance imaging (MRI) contrast agent (Mn-iCOF)
was constructed based on the Mn(II)-chelated ionic covalent organic
framework (iCOF). Because of the porous structure and hydrophilicity,
the Mn-iCOF has a high longitudinal relaxivity (r
1) of 8.02 mM–1 s–1 at 3.0 T. For the tumor-bearing mice, a lower dose (0.02 mmol [Mn]/kg)
of Mn-iCOF demonstrated a higher signal-to-noise ratio (SNR) value
(1.8) and longer retention time (2 h) compared to a 10-fold dose of
commercial Gd-DOTA (0.2 mmol [Gd]/kg). Moreover, the Mn-iCOF can provide
continuous and significant MR contrast for the popliteal LNs within
24 h, allowing for accurate evaluation and dissection of LNs. These
excellent MRI properties of the Mn-iCOF may open new avenues for designing
more biocompatible MRI contrast agents with higher resolutions, particularly
in the diagnosis of TNBC.
The sensitive detection of dopamine (DA), especially the accurate monitoring of cell secreted DA, is necessary to the study of pathogenesis of central nervous system disease. Here, the cobalt-modified nitrogen doping carbon aerogels (Co-NCA) with three-dimensional pores were successfully synthesized through the hydrothermal and freeze-drying method of the biomass. As a natural substance, starch is the carbon source of Co-NCA, which is environmentally friendly. The electrochemically active area of an electrode modified by Co-NCA was about 1.53 times that of carbon aerogels. Benefiting from the Co and N element, the Co-NCA modified electrode (Co-NCA/GCE) showed that Co-NCA had a wider linear range (0.2-200 and 200-1000 μM) and a lower detection limit (55.6 nM) towards DA. The reproducibility and repeatability of Co-NCA/GCE for detecting 500 M DA was 2.21% and 0.797%, respectively. After being stored at 4°C for 7 days, the current response of Co-NCA/GCE still maintained 96.5% of the initial current value. Finally, the Co-NCA/GCE was successfully applied to the monitoring of DA, which was released from PC12 cells after stimulated by 50 mM K+.
In this report, a novel electrochemical and colorimetric dual-mode sensing system was developed for the sensitive and selective detection of DA. The large surface area of CoOOH and the excellent conductivity of CB endow the electrochemical sensing system with high sensitivity. CoOOH with oxidase-like activity will convert the colorless TMB into the blue oxidation product OXTMB, appearing an absorption peak at 652 nm correspondingly. And the addition of DA will inhibit the activity of oxidase followed by a reducing in the absorption. The proposed method provided a wider detection range for DA from 1 to 30 μM and 1 to 950 μM through colorimetric and electrochemical methods, respectively. Furthermore, this biosensor with good biocompatibility has been successfully used for tracking of DA efflux from live PC12 cell after being stimulated, which has important scientific and practical value for clinical diagnosis and monitoring.
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