Advances in aptamer-based sensing assays for C-reactive protein.

C-reactive protein (CRP), a non-specific acute-phase indicator of inflammation, has been widely recognized for its value in clinical diagnostic applications. With the advancement of testing technologies, there have been many reports on fast, simple, and reliable methods for CRP testing. Among these, the aptamer-based biosensors are the focus and hotspot of research for achieving high-sensitivity analysis of CRP. This review summarizes the progress of in vitro aptamer screening for CRP and the recent advances in aptamer-based CRP sensor applications, thus developing insight for the new CRP aptasensor design strategy.

Determination of Flavonoid Glycosides by UPLC-MS to Authenticate Commercial Lemonade.

So far, there is no report on the quality evaluation of lemonade available in the market. In this study, a sample preparation method was developed for the determination of flavonoid glycosides by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) based on vortex-assisted dispersive liquid-liquid microextraction. First, potential flavonoids in lemonade were scanned and identified by ultra-performance liquid chromatography-time of flight mass spectrometry (UPLC-TOF/MS). Five flavonoid glycosides were identified as eriocitrin, narirutin, hesperidin, rutin, and diosmin according to the molecular formula provided by TOF/MS and subsequent confirmation of the authentic standard. Then, an ultra-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-QqQ/MS) method was developed to determine these five flavonoid glycosides in lemonade. The results showed that the content of rutin in some lemonade was unreasonably high. We suspected that many illegal manufacturers achieved the goal of low-cost counterfeiting lemonade by adding rutin. This suggested that it was necessary for relevant departments of the state to make stricter regulations on the quality standards of lemonade beverages.

[Adeno-associated vector mediated intracellular biological activity of human Kallistatin].

Human tissue kallikrein-binding protein (Kallistatin, KAL), a secretory protein that participates in the regulation of multiple signaling pathways by binding to the extracellular receptor, however, at present has not been reported about the intracellular activity, and whether it has the similar biological activity with extracellular activity. Here we constructed no signal peptide KAL (NSK) into the adeno-associated virus vector to explore the intracellular activity of KAL. Both the endothelial cell and lung cancer cells could express KAL, but not secreted after rAAV2-NSK transfection. The proliferation and migration of human umbilical vein endothelial cells (HUVECs) were inhibited, but the apoptosis rate was not affected. The proliferation rates, mobility and tubule formation of all the three tested lung cancer cells, such as NCI-H446, NCI-H460 and A549, were inhibited to different extents. This cellular study not only confirmed the intracellular activity, but also suggested it may serve as a kind of "balance factor" in multi-targeted controlling, which may provide a new train of thoughts to explain the regulatory contradiction in PI3K-Akt signaling pathways by KAL.

Epstein-Barr virus is a promoter of lymphoma cell metastasis.

It is well-known that Epstein-Barr virus (EBV) is the promoter of cell tumourigenesis. We found that EBV is also a promoter of lymphoma cell dissemination, because we found the typical morphopathological phenomenon of cell adhesion, which confirmed that the adhesion of tumour cells was higher than that of normal cells. We also observed that tumour cells disrupted the dynamic pathological changes of vascular endothelial cells, and this made it clear that the rate of tumour cell metastasis was directly proportional to the degree of EBV infection. Furthermore, when we discovered exosomes, it was considered that this was associated with cancer stem cells, suggesting the formation of a microenvironment before tumour cell metastasis. In addition, competitive inhibition was found in cell adhesion, indicating the breakthrough point of preventing tumour cell metastasis, which has clinical reference value for tumour immunotherapy.

A sandwich ELISA-like detection of C-reactive protein in blood by citicoline-bovine serum albumin conjugate and aptamer-functionalized gold nanoparticles nanozyme.

C-reactive protein (CRP) level in blood is associated with the risk of developing cardiovascular events in higher-risk populations. We present a sandwich ELISA-like assay for the determination of CRP in blood by citicoline-bovine serum albumin (citicoline-BSA) conjugate and aptamer-functionalized gold nanoparticles (aptamer-AuNPs) nanozyme. The CRP in the blood sample was selectively adsorbed to the ELISA plate coated by citicoline-BSA, and then incubated with added aptamer-AuNPs. AuNPs exhibited peroxidase activity and oxidized 3,3'5,5'-tetramethylbenzidine from colorless to blue, achieving the measurement at 652 nm. The amplified signal increased linearly in a wide range from 0.1 to 200 ng mL-1 and with a detection limit of 8 pg mL-1. Finally, the method was further tested using rat blood from an isoproterenol-induced myocardial infarction experimental model to confirm its applicability. The developed method could directly determine CRP in blood sample after dilution with high accuracy and sensitivity. This method has many advantages, such as easiness to prepare materials, good stability between batches, high specificity, low detection limit, low-cost, easiness to operate with simple instruments, the most remarkable of which is its excellent lot-to-lot stability over the classical ELISA.