1,720,995 research outputs found
Rational design of site-specific artificial metallonucleases for therapeutic applications
No full textArtificial metallonucleases (ArMNs) are synthetic nucleases that utilise metals as the catalytic centre for cleaving nucleic acids, with the metal component present in the form of ions, complexes or nanoparticles. ArMNs have been developed as therapeutics for a range of diseases, including genetic disorders, cancer and infectious diseases. Achieving high site-specificity in ArMNs is crucial for their effective application in targeted therapeutic interventions. By employing advanced methodologies, these engineered nucleases can induce targeted modifications in the genome, thereby advancing genetic research, improving disease treatment and fostering biotechnological innovation. This review examines recent advancements over the past 20 years in the design and synthesis of site-specific ArMNs. Illustrated examples are provided to elucidate the underlying principles of their site-specific activity and to highlight their prospective applications. Additionally, strategies for overcoming challenges in enhancing the selectivity of these nucleases are discussed, and anticipated future research directions in this dynamic field are outlined
Integrated RPA-CRISPR/Cas12a system towards Point-of-Care H. pylori detection
No full textThe rapidly advanced CRISPR/Cas biosensing technology provides unprecedent potential for the development of novel biosensing systems. It provides a new approach for realizing rapid, sensitivity and highly specific pathogen nucleic acid detection, with the capability to combine other technologies, including Polymerase Chain Reaction or isothermal amplifications. The detection of Helicobacter pylori (H. pylori), one of the most common human pathogens to cause various gastroduodenal diseases, has also been explored with the assistance of CRISPR/Cas systems. However, gaps still remain for the development of end-user friendly sensing systems.In this study, a combined RPA-CRISPR/Cas12a biosensing system has been established. It shown the capability to quantitively detect the presence of H. pylori genome DNA with 4 orders of magnitude linear range, and sensitivity of 1.4 copies/μL. The overall reaction can be done within 45 mins at room temperature, which eliminates the needs for heating instrumentation. In addition, with the addition of pullulan as a protective reagent, the potential of storing CRISPR/Cas12a system reagents by using a freeze-dry approach has also been demonstrated.Clinical Relevance-This study represents a novel exploration to applying CRISPR/Cas12a-based biosensing technology to the detection of pathogen DNA with improved potential for the development of Point-of-Care diagnostics. This critical aspect of our technology will contribute to address the newly emerged pathogenic threats and support public health systems.</p
RNA reporter based CRISPR/Cas12a biosensing platform for sensitive detection of circulating tumor DNA
No full textCRISPR/Cas biotechnology provides an exceptional platform for biosensor development. To date, the reported CRISPR/Cas biosensing systems have shown extraordinary performance for nucleic acids, small molecules, small proteins and microorganism detection. The CRISPR/Cas12a biosensing system, as a typical example, has been well established and applied for both nucleic acids and non-nucleic acids target detection. However, all established CRISPR/Cas12a biosensing systems are based on DNA reporters, which potentially limits further application.In this study, we established an RNA reporter based CRISPR/Cas12a biosensing system. A basic biosensing system was evaluated, and the limit of detection was found to be 1 nM. Afterwards, we optimized this biosensing system using both temperature and chemical enhancers. The final optimal biosensing system (with DTT & 37°C) shows fluorescence signal increased by a factor of ~10 compared with the basic system. The optimal biosensing system was further applied for the detection of circulating tumor DNA (ctDNA), which shows over 4 orders of magnitude detection range from 1pM to 25 nM, with the limit of detection of 1pM. This RNA reporter based CRISPR/Cas12a biosensing system provides an effective platform for nucleic acids quantification.Clinical Relevance-This research provides a novel approach for ctDNA diagnostics, which is an attractive biomarker for noninvasive monitoring of tumor growth, response, and spread.</p
Activation of the hippocampal AC-cAMP-PKA-CREB-BDNF signaling pathway using WTKYR in depression model rats
No full textDepression, also called “depression disorder,” is characterized by a significant and persistent low mood. It has become a major refractory disease in the 21st century. In recent years, Chinese medicine has shown some important clinical value in the treatment of depression. Among them, the Warming and “Tonifying” Kidney-Yang Recipe (WTKYR) has been demonstrated to have obvious effects in the clinical treatments of depression; however, the mechanism remains unclear. This study is based on the adenylyl cyclase (AC)—cyclic adenosine monophosphate (cAMP)—protein kinase A (PKA)—cAMP response element-binding protein (CREB)—brain derived neurotrophic factor (BDNF) signaling pathway, aiming to investigate the mechanism of WTKYR. The results showed that WTKYR can upregulate AC-cAMP-PKA-CREB-BDNF in the hippocampus of depression model rats and alleviate its depressive symptoms, which may be the mechanism of WTKYR.</p
Paper-based lateral flow assay for the point-of-care detection of neurofilament light chain
No full textNeurofilament light chain (NF-L) is a protein found in neurons of the nervous system and is widely used as a biomarker for neurological disorders. However, the current methods for detecting NF-L levels are complicated, expensive, and require specialized equipment, making it challenging to implement in a point-of-care (POC) setting. In this study, we developed a gold nanoshell (AuNS)-assisted lateral flow assay (LFA) based test strip for the POC detection of NF-L at a low ng/mL level (8 ng/mL = 117.65 pM). The test strip is a simple, rapid, and cost-effective method for detecting NF-L, making it suitable for use in a POC setting for the diagnosis and treatment of various neurological disorders. With its ease of use and reliability, the paper-based LFA is a valuable tool for the diagnosis and management of neurological conditions.Clinical Relevance - The AuNS-assisted LFA test strip developed in this study offers a rapid, cost-effective, and simple method for detecting NF-L levels, making it of great interest to practicing clinicians for the diagnosis of various neurological diseases such as HIV-associated dementia (HID), Amyotrophic Lateral Sclerosis (ALS), and Creutzfeldt-Jakob disease (CJD).</p
Point-of-care testing of procalcitonin using lateral flow assay
No full textThis study presents a novel gold nano shells (GNS)-assisted paper-based lateral flow assay (LFA) for the detection of procalcitonin (PCT). PCT is a biomarker of infection, originating from the C cells of the thyroid gland and functioning as a precursor to the hormone calcitonin. Its concentration in the blood is known to increase in line with the progression of infectious diseases. Conventional techniques for assessing PCT levels in the blood encompass culture-based methods, enzyme-linked immunosorbent assay (ELISA) and electrochemical immunoassays. These methods are characterized by either prolonged processing times, high costs, or dependence on laboratory infrastructure. These limitations hinder their practical implementation in point-of-care settings. As a result, the development of a LFA for detecting PCT levels proves to be well-suited for point-of-care settings, serving as a valuable diagnostic tool for infectious diseases. This study focuses on comparing the efficacy of GNS and gold nanoparticle (GNP)-assisted lateral flow assays (LFA) to ascertain the lower limit of detection (LOD) for PCT and assess their overall reliability. Our findings indicate that GNS-assisted LFA achieved a lower LOD of 1 ng/mL, surpassing GNP, which exhibited a LOD of 5 ng/mL. Furthermore, outstanding specificity was demonstrated and clinical application capability in human serum was confirmed, reinforcing its efficacy as a reliable platform.Clinical</p
PLGA nanoparticles with folate-conjugation and co-encapsulation of doxorubicin, quantum dots and SPIONS for cancer drug delivery and dual-modality imaging
No full textDoxorubicin (Dox) is a traditional chemotherapy drug, which has significant side effects, such as cardiotoxicity, mucositis, and myelosuppression. Meanwhile, many tumor cells also have a multi-drug resistant (MDR), which results in lower drug concentration in the tumor cells, and reduces its therapeutic effect. So, it is an important work for us to improve the selective delivery of DOX. Recently, using various nanocarriers encapsulated with anticancer drugs or inorganic nanoparticles which possessing special imaging effects for targeted delivery to tumor cells, gradually become a focus in the field of the nano-biotechnology research.In this study, CdSe/ZnS quantum dots, superparamagetic iron oxide nanocrystals (SPIONs) and doxorubicin (Dox) are co-encapsulated into PLGA [poly(d,l-lactic-co-glycolic acid)]-based polymeric nanoparticles using a double emulsion solvent evaporation method (W/O/W), followed by coupled to the amine group of the polyethyleneimine (PEI) pre-modified with polyethylene glycol–folic acid segments (PEI–PEG–FA), the FA-targeted PEGylated PLGA NPs (QDs/DOX/Fe3O4@PLGA/PEI–PEG–FA) were formed for tumor specific targeting drug delivery and dual-modality imaging. SEM, TEM, EDX, ξ-potential analysis, fluorescence spectroscopy, ultraviolet and visible spectrophotometer were carried out to characterize the morphology, composition, and properties of the as-prepared composite nanoparticles. The mean diameter of the QDs/DOX/Fe3O4@PLGA/PEI–PEG–FA is 317 nm, which is dispersive and sable in water. When the weight ratio of DOX to PLGA was 100 (mg DOX/g PLGA), the encapsulation efficiency and the drug loading can be reached approximately 77.81% and 7.75% respectively. And the drug release was higher in an acid pH environment (pH 4.0) than in the physiological pH environment (pH 7.0). QDs/DOX/Fe3O4@PLGA/PEI–PEG–FA nanocomposite can be targeted to tumor cells with high expression of the folate receptor, reducing the side effects of Dox on normal tissues. It may be great promising for this nanocomposite to become an effective drug delivery system for tumor-targeted drug delivery and MR/optical dual-modality imaging
Magnetic mesoporous silica nanoparticles co-delivering doxorubicin and VEGF siRNA for cervical cancer targeting therapy and MR imaging
No full textRNA interference (RNAi) has been widely applied in biology and medicine because it can down-regulate the expression of specifically targeted genes. However, considerable barriers need to be overcome for delivery naked siRNA to appropriate site including rapid degradation by serum nucleases, hepatic clearance, low transfection efficiency, off-target effect, and inefficient release from endosomes. Therefore, developing effective delivery carrier holds the key to successful in clinical application of therapeutic siRNA. Inhibition of the vascular endothelial growth factor (VEGF) expression has been proven to effectively inhibit tumor growth and metastasis. The use of single chemotherapeutic drug has shown some limitations in anti-tumor treatment. Combining chemotherapy and gene therapy may be a promising approach for cancer treatment.In this study, a multifunctional co-delivery nanocarrier based on magnetic mesoporous silica nanoparticles(M-MSNs) was designed to simultaneously deliver VEGF shRNA and doxorubicin (Dox) in vitro and in vivo. The abundant pores on the surfaces of M-MSNs improved drug loading capacity. The targeting ligand folic acid (FA) conjugated polyethyleneimine (PEI-FA) was coated on the M-MSN surfaces through electrostatic interactions. PEI-FA modification increases VEGFshRNA binging capability because of electrostatic interactions between amino groups of PEI-FA and VEGF shRNA. The nanocomplexes were characterized by scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller (BET) and zeta potential assy. The M-MSN(Dox)/PEI-FA nanocomplexes had average particle size of 217 ± 1 nm and drug-loading amount of 15%. They were stable and well-dispersed in 10% fetal bovine serum and had ability to protect VEGF shRNA degradation. Confocal microscopy confirmed that the FA receptor-mediated endocytosis of the M-MSN(Dox)/PEI-FA/VEGF shRNA composite was greater than that of the M-MSN(Dox)/PEI in folate receptor-overexpressed HeLa cells. The M-MSN(Dox)/PEI-FA/VEGF shRNA nanocomplexes also demonstrated excellent gene silencing efficiency in vitro and reduced the expression of VEGF expression. The in vitro magnetic resonance (MR) imaging indicated that M-MSN(DOX)/PEI-FA could be also used as an excellent MR contrast agent. Our results suggested that the M-MSN(Dox)/PEI-FA/VEGF shRNA nanocomplexes are a safe and efficient integration platform for MR imaging and co-delivering Dox and VEGF shRNA
Paper-based SERS analysis with smartphones as Raman spectral analyzers
No full textSERS (Surface Enhanced Raman Spectroscopy) can realize fingerprint recognition of molecular samples with high detection accuracy and sensitivity. However, rapid and convenient measurement of the Raman spectra of analytes for a point-of-care test (POCT) has put forward a high demand for portable Raman spectrometers, as well as reliable SERS substrates. Hereby, we first utilize a smartphone as a miniaturized Raman spectral analyzer, which has the revolutionary advantages of a friendly human-machine interface, fast measurement time, and good sensitivity. Meanwhile, a paper-based SERS chip was prepared based on commonly used filter paper and silver nanoparticles (AgNP), which was successfully used to detect low concentrations of typical SERS analyte model molecules including rhodamine 6G and crystal violet. The current method of smartphone-based SERS spectroscopy as a POCT device will greatly promote the application of Raman technology in a variety of scenarios, such as safety inspections, pesticide residue detection, water pollution monitoring, and so on. Coupled with paper-based SERS chips with advantages of facile preparation, low cost and good reliability, the current work proves to have a great potential for industrial production and for meeting the vast marketing demand of Raman based POCT technology.</p
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