Current signal amplification strategies in aptamer-based electrochemical biosensor: A review

Nano-Albumin Particles Loaded with miR-20a Inhibitor Targeting Met Protein to Reverse Proliferation of Intestinal Cancer Cells

This study explored miR-20a’s role in intestinal cancer cells. SW480 cell line was divided into control group, agonist group, inhibitor group, and negative control group, followed by analysis of cell proliferation, apoptosis, Met, Bad, and Bcl-2 protein expressions. Results showed that miR-20a expression in the agonist group was the highest, followed by blank group and negative control group, and inhibitor group was lowest. S-phase and G2/M cell number from inhibitor group was lowest, and cell apoptosis rate was highest. However, the agonist group showed contrary changes. There was no difference in G0/G1 phase cell number among the four groups (P > 0.05). Moreover, the expressions of Bad, Bcl-2, Met, Wnt, β-catenin, and p-Wnt in inhibitor group were all lower, while the expressions in agonist group were all high (P < 0.05). S-phase and G2/M cell number in inhibitor group was lowest, while cell apoptosis was highest. The agonist group was opposite, with G0/G1 phase cells in each group showing no difference (P > 0.05). Wnt, β-catenin, and p-Wnt expressions were lowest in the inhibitor group, while the agonist group was opposite. These results together showed that the miR-20a directly targeted and regulated Met protein. Finally, the miR-20a inhibited intestinal cancer cell proliferation mainly through inhibiting Wnt/β-catenin signaling activity.

DNA Templated Silver Nanoclusters for Bioanalytical Applications: A Review

Due to their unique programmability, biocompatibility, photostability and high fluorescent quantum yield, DNA templated silver nanoclusters (DNA Ag NCs) have attracted increasing attention for bioanalytical application. This review summarizes the recent developments in fluorescence properties of DNA templated Ag NCs, as well as their applications in bioanalysis. Finally, we herein discuss some current challenges in bioanalytical applications, to promote developments of DNA Ag NCs in biochemical analysis.

DNA-Based Biosensors for the Biochemical Analysis: A Review

In recent years, DNA-based biosensors have shown great potential as the candidate of the next generation biomedical detection device due to their robust chemical properties and customizable biosensing functions. Compared with the conventional biosensors, the DNA-based biosensors have advantages such as wider detection targets, more durable lifetime, and lower production cost. Additionally, the ingenious DNA structures can control the signal conduction near the biosensor surface, which could significantly improve the performance of biosensors. In order to show a big picture of the DNA biosensor's advantages, this article reviews the background knowledge and recent advances of DNA-based biosensors, including the functional DNA strands-based biosensors, DNA hybridization-based biosensors, and DNA templated biosensors. Then, the challenges and future directions of DNA-based biosensors are discussed and proposed.

Circulating Abnormal Extracellular Vesicles: Their Mechanism for Crossing Blood-Brain Barrier, Effects on Central Nervous System and Detection Methods

Central nervous system (CNS) diseases are difficult to treat and harmful. Many CNS diseases are secondary to peripheral diseases, such as tumor brain metastases (BMS), viral infections and inflammation of the brain, and their pathogenic factors travel through the circulatory system to the brain, eventually leading to lesions. Extracellular vesicles (EVs) play an important role in this process. Recent studies have shown that, extracellular EVs can effectively cross the blood- brain barrier (BBB) through endocytosis and they transmit molecular signals in cell-to-cell communication. Abnormal EVs produced in the lesion portion transport pathogenic factors, including miRNAs, proteins, and virions into the CNS. These pathogenic factors participate in cellular pathways to interfere with homeostasis or are themselves pathogens that directly damage CNS. In addition, different or specific pathological molecules in EVs are potential disease markers. We herein reviewed pathways through which the abnormal EVs cross BBB and adverse effects of abnormal exosomes. We also and summarized their existing detection techniques, so as to provide basis for prevention and early diagnosis of secondary diseases.

Nucleus-Targeted Nanoparticles Induce Autophagy of Vascular Endothelial Cells in Cervical Spondylosis of Vertebral Artery Type Through PI3K/Akt/mTOR Signaling Pathway

Nanoparticles are characterized by their large surface area per unit and high dispersion, with excellent affinity and adhesion to the tissue, which help them to contact drugs with tissues. However, the relationship between nuclear-targeted nanoparticles and PI3K/Akt/mTOR pathway, as well as their roles in cervical spondylosis of vertebral artery type (CSA) remain unclear. bEnd.3 cells were in this study exposed to nuclear-targeted nanoparticles, followed by determination of cell biological processes. The role of nuclear-targeted nanoparticles in CSA in relation to PI3K/Akt/mTOR pathway was then analyzed through detection of autophagy-related proteins pathway-related proteins. Nuclear-targeted nanoparticles led to reduced bEnd.3 cell proliferation with IC50 at indicated time points shown as (12.8±0.67), (8.8±0.43), and (4.6±0.42) μmol/L, respectively. Nuclear-targeted nanoparticles blocked bEnd.3 cells in G2/M phase, and induced apoptosis. In addition, nuclear-targeted nanoparticles inhibited the PI3K/Akt/mTOR pathway in the bEnd.3 cells, as evidenced by reduced PI3K, Akt and mTOR levels. Nuclear-targeted nanoparticles decreased the expression of Beclin-1, LC3, p62, Cathepsin D, and ATG5, and increased expression of GSK-3 and Bcl-2. Our present study demonstrated that the nucleartargeted nanoparticles could regulate the growth of bEnd.3 cells in CSA and promote autophagy of cells through blockage of the PI3K/Akt/mTOR signaling pathway.

Icariin Attenuation of Diabetic Kidney Disease Through Inhibition of Endoplasmic Reticulum Stress via G Protein-Coupled Estrogen Receptors

Diabetic kidney disease (DKD) is the most common complication of diabetes mellitus and has become the primary cause of End-Stage Renal Disease (ESRD) globally. Icariin (ICA), an effective component extracted from Epimedium, has antiosteoporosis effect, antitumor effects, anti-ischemia effects, and other effects. In this study, a mouse DKD model was established, and Icariin solid nanoliposomes were administered to determine whether ICA had a protective effect on the renal function of DKD mice by regulating estrogen level and endoplasmic reticulum (ER) stress pathway. The results showed that the microalbumin/creatinine in urine, serum urea nitrogen, and CHOL in ICA cultured DKD mice significantly decreased, and mice nephropathy improved significantly. rat renal tubule epithelial cells were further tested, and the rat renal tubule epithelial cells were modeled by cultured cells with high glucose. The results showed that high glucose could promote the proliferation of renal tubular epithelial cells. Simultaneously, ICA can inhibit the proliferation of renal tubular epithelial cells and induce cell apoptosis. Furthermore, the expression of ER stress-related proteins IRE1 and XBP-1S was further detected. Additionally, to ICA intervention, a GPER antagonist (G-15) was added for intervention, the inhibitory effects of IRE1 and XBP-1S were reversed, and the ER stress pathway was activated. Cell experiments showed that ICA could promote GPER expression, while inhibiting GPER expression promoted the activation of ER stress pathway, and GPER expression was negatively correlated with ER stress protein expression. Therefore, the experiment proved that in DKD tissues, a high concentration of ICA can inhibit the ER stress response by promoting the expression of GPER, reducing the proliferation of diabetic nephropathy, and increasing the rate of tissue apoptosis.

Effect of Polysaccharide Sulfate-Loaded Poly(lactic-co-glycolic acid) Nanoparticles on Coronary Microvascular Dysfunction of Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM) mainly results from development of coronary microcirculatory dysfunction (CMD). Polysaccharide sulfate (PSS), as one heparin drug, has a variety of biological activities. This study examined the efficacy of a new type of PSS-loaded poly lactic-co-glycolic acid (PLGA) nanoparticles (PSS-NPs) on DCM, in finding a theoretical basis for CMD treatment. After establishment of DCM model, the animals were administrated with PSS, PSS-NPs, normal saline or poly(ethylene glycol)1 (PEG1) through intraperitoneal injection. 8 weeks after injection of streptozotocin (STZ), heart function of rats was assessed by echocardiography. The rat tissues were collected and detected by histological analysis. Quantitative reverse transcription PCR (RT-qPCR) and Western blot analyses determined the levels of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), and pro-inflammatory factors. PSS-NPs had a good protective effect on cardiac insufficiency in rats. Administration of PSS-NPs prolonged survival state, and enhanced cardiac function, thereby alleviating the symptoms, and inducing formation of micro vessels. Importantly, it improved the symptoms of DCM patients and their quality of life. Moreover, pro-inflammatory factor levels decreased upon the treatment, accompanied with inactivation of NF-κB signaling pathways, thereby improving DCM. This study demonstrated that the PSS-NPs significantly relieved DCM and restored cardiac function in rats through NF-κB signaling pathways, providing a theoretical basis for development of PSS-NPs, and new treatment ideas for CMD of DCM.

Lateral Flow Strip Assay for Detection of Mycoplasma hyorhinis Based on a Pair of Sandwich-Type Aptamers

Mycoplasma hyorhinis is a normal flora in swine respiratory tract and also often found in multiple human tumor tissues, which is considered to be highly correlated with human tumors. Due to the detection of Mycoplasma hyorhinis mainly relies on PCR-based assay at present, thus it is critical for developing a novel assay for rapid detection and providing support diagnosis evidence. In our work, we screened and characterized a high affinity aptamer zyb1 that can recognize Mycoplasma hyorhinis based on infectious cell-SELEX. On this basis, we developed a lateral flow strip assay by using zyb1 and another aptamer AP15-1 to form a sandwich-type aptasensor. Using this new lateral flow strip assay biosensor, Mycoplasma hyorhinis could be detected within the detectable limit as low as 1 × 10³ CCU/mL. Therefore, our study successfully developed a convenient and effective lateral flow strip for Mycoplasma hyorhinis detection and demonstrated the potential of utilizing aptamer for the development of point-of-care testing products for mycoplasma detection.

Recent Advances in Engineered Noble Metal Nanomaterials as a Surface-Enhanced Raman Scattering Active Platform for Cancer Diagnostics

Recently, noble metal nanomaterials have been extensively studied in the fields of biosensing, environmental catalysis, and cancer diagnosis and treatment, due to their excellent electrical conductivity, high surface area, and individual physical and optical properties. Early research on the surface-enhanced Raman scattering (SERS) effect was focused on the cognition of the SERS phenomenon and enhancing its sensitivity for single-molecule detection. With the development of nanomaterials and nanotechnology, the advances and applications based on SERS substrates have been accelerated. Among them, noble metal nanomaterials are mainly used as SERS-active substrates to enhance SERS signals owing to their compelling surface plasmon resonance (SPR) properties. This review provides recent advances, perspectives, and challenges in SERS assays based on engineered noble metal nanomaterials for early cancer diagnosis.

A ratiometric electrochemical biosensor for glycated albumin detection based on enhanced nanozyme catalysis of cuprous oxide-modified reduced graphene oxide nanocomposites

Nanozymes have enzyme-like characteristics and nanozyme-based electrochemical sensors have been widely studied for biomarker detection. In this work, cuprous oxide-modified reduced graphene oxide (Cu₂O-rGO) nanozyme was prepared by simultaneous reduction of copper chloride and graphene oxide. This Cu₂O-rGO nanozyme displayed an outstanding electrocatalytic activity to glucose oxidation and was used as the modified material of a glassy carbon electrode to fabricate an electrochemical ratiometric biosensor for glycated albumin (GA) detection. In this ratiometric biosensor, methylene blue-labeled DNA tripods (MB-tDNA) were adsorbed on the Cu₂O-rGO/GCE surface to form a bioinspired electrode (MB-tDNA/Cu₂O-rGO/GCE), in which the catalytic sites of Cu₂O-rGO were covered by MB-tDNA. In the presence of target GA, GA could be identified by the aptamer sequence contained in MB-tDNA, and a MB-tDNA/GA complex was formed and released into the solution, so the reduced current of MB-tDNA was decreased. Simultaneously, the oxidized current of the outer added glucose was increased since more catalytic sites of Cu₂O-rGO nanozyme on the substrate electrode surface were exposed. The ratio of the peak currents of glucose oxidation and methylene blue reduction (I_Glu/I_MB) was used to monitor the GA level and ultimately improve the accuracy of the method. The electrochemical sensor showed a low detection limit of 0.007 μg mL^-1 and a wide linear range from 0.02 to 1500 μg mL^-1. The proposed sensor was also successfully used to measure the GA expression level in the blood serum of a diabetic mouse model.

Selection of a High-Affinity DNA Aptamer for the Recognition of Cadmium Ions

Cadmium ions as toxic metallic pollutants have been dramatically risen due to industrial production, which causes serious environmental damages and potential health risks. Thus, developing sensitive and specific probes to recognize cadmium ions is vital for human and environmental safety. In this work, the aptamer as a capture probe was selected for the identification of cadmium ions. The modified SELEX method based on immobilizing ssDNA libraries on streptavidin magnetic beads was used to the high-affinity aptamer selection for binding cadmium ions. After 9 rounds of selection, 4 ssDNA sequences with the highest enrichment were obtained, and the Cd-1 aptamer exhibited the highest affinity to cadmium ions. The dissociation constant K_d value of the Cd-1 aptamer was 81.39 μM for cadmium ions. Later, we also investigated the binding specificity of Cd-1 aptamer toward other heavy metal ions. Given the availability of immobilizing ssDNA library on matrix, we believe the strategy also applies to discover other ions in a reproducible manner.

Applications of Aptamer-Bound Nanomaterials in Cancer Therapy

Cancer is still a major disease that threatens human life. Although traditional cancer treatment methods are widely used, they still have many disadvantages. Aptamers, owing to their small size, low toxicity, good specificity, and excellent biocompatibility, have been widely applied in biomedical areas. Therefore, the combination of nanomaterials with aptamers offers a new method for cancer treatment. First, we briefly introduce the situation of cancer treatment and aptamers. Then, we discuss the application of aptamers in breast cancer treatment, lung cancer treatment, and other cancer treatment methods. Finally, perspectives on challenges and future applications of aptamers in cancer therapy are discussed.