A simple visual method for DNA detection based on the formation of gold nanoparticles

Pt Nanodot Inlaid Mesoporous NaBiOF Nanoblackberry for Remarkable Signal Amplification Toward Biomarker Detection

A new ultrasensitive sandwich-type electrochemical immunosensor has been successfully constructed to quantitatively detect carcinoembryonic antigen (CEA) using blackberry-like mesoporous bismuth-based nanospheres NaBiOF (NBOF NSs) inlaid with Pt nanodots (NDs) (BiPt NSs) as the antibody capture and signal-amplifying probe. The growth of Pt NDs inside the holes of NBOF NSs formed the nanozyme inlay outside NBOF NSs, greatly increasing the specific surface area and exposure of the catalytic active sites by minimizing the particle size of the Pt to nanodot scale. Such a blackberry-shaped heterojunction structure of BiPt NSs was well-suited to antibody capture and improved the catalytic performance of BiPt NSs in reducing H₂O₂, amplifying the signal, and yielding highly sensitive detection of CEA. The use of Au nanoparticle-modified multi-walled carbon nanotubes (Au@MWCNTs) as the electrode substrates significantly enhanced the electron transfer behavior over the electrode surface, further increasing the conductivity and sensitivity of the immunosensor. Remarkably, good compatibility with human body fluid was achieved using the newly developed BiPt-based immunosensor resulting from the favorable biocompatibility and stability of both BiPt NSs and Au@MWCNTs. Benefiting from the double signal amplification strategy and the high biocompatibility, the immunosensor responded linearly to CEA in a wide range from 50 fg/mL to 100 ng/ml with an extremely low detection limit of 3.52 fg/mL (S/N = 3). The excellent detection properties of this new immunosensor were evidenced by the satisfactory selectivity, reproducibility, and stability obtained, as well as the reliable and precise determination  of CEA in actual human blood samples. This work provides a new strategy for the early clinical diagnosis of cancer. Novel blackberry-like mesoporous NaBiOF nanospheres with Pt nanodot inlay were successfully usedto construct a sandwich-type electrochemical immunosensor for the ultra-sensitive detection ofcarcinoembryonic antigen in human blood plasma based on a remarkable signal amplification strategy.

The self-powered electrochemical biosensing platform with multi-amplification strategy for ultrasensitive detection of microRNA-155

A self-powered biosensor (SPB) was constructed for the ultra-sensitive detection of microRNA-155 (miR-155) by combining a capacitor/enzymatic biofuel cell (EBFC), a strategy of rolling circle amplification (RCA) and a digital multimeter (DMM). The experimental results show that the sensitivity of the assembled EBFC-SPB can reach 15.85 μA/pM with the action of matching capacitor, which is 513% of that without capacitor (3.09 μA/pM). This achieves the first signal amplification. Furthermore, when the target miR-155 triggers RCA, electrons are continuous generated and flow to the biocathode through the external circuit to catalyze the reduction of oxygen and release [Ru(NH₃)₆]³⁺ electron acceptor. This achieves the second signal amplification. Finally, DMM is used to convert the signal into instantaneous current and amplify it for real-time reading. This achieves the third signal amplification. Therefore, the limit of detection (LOD) of the developed biosensor is as low as 0.17 fM (S/N = 3), and the linear range is between 0.5 fM and 10,000 fM, indicating that the EBFC-SPB has a broad application prospect for cancer marker of miR-155 with ultrasensitive detection.

Label-Free Aptasensor for Detection of Fipronil Based on Black Phosphorus Nanosheets

A label-free fipronil aptasensor was built based on Polylysine-black phosphorus nanosheets composition (PLL-BPNSs) and Au nanoparticles (AuNPs). A PLL-BP modified glassy carbon electrode (GCE) was fabricated by combining BP NSs and PLL, which included a considerable quantity of -NH₂. Au nanoparticles (AuNPs) were placed onto the GCE, and PLL-BPNSs bonded to Au NPs firmly by assembling. The thiolated primers were then added and fixed using an S-Au bond, and competitive binding of the fipronil aptamer was utilized for fipronil quantitative assessment. The sensor’s performance was evaluated using differential pulse voltammetry (DPV) method. The linear equation is ΔI (μA) = 13.04 logC + 22.35, while linear correlation coefficient R² is 0.998, and detection limit is 74 pg/mL (0.17 nM) when the concentration of fipronil is 0.1 ng/mL–10 μg/mL. This aptasensor can apply to quantitative detection of fipronil.

Application of Janus Particles in Point-of-Care Testing

Janus particles (JPs), named after the two-faced Roman god, are asymmetric particles with different chemical properties or polarities. JPs have been widely used in the biomedical field in recent years, including as drug carriers for targeted controlled drug release and as biosensors for biological imaging and biomarker detection, which is crucial in the early detection and treatment of diseases. In this review, we highlight the most recent advancements made with regard to Janus particles in point-of-care testing (POCT). Firstly, we introduce several commonly used methods for preparing Janus particles. Secondly, we present biomarker detection using JPs based on various detection methods to achieve the goal of POCT. Finally, we discuss the challenges and opportunities for developing Janus particles in POCT. This review will facilitate the development of POCT biosensing devices based on the unique properties of Janus particles.

Novel miniaturized fluorescence loop-mediated isothermal amplification detection system for rapid on-site virus detection

New pathogen outbreaks have progressed rapidly and are highly infectious in recent years, increasing the urgency of rapid and accurate detection of pathogenic microorganisms. Based on the point-of-care testing (POCT) requirements, in this study, a real-time fluorescent loop-mediated isothermal amplification (LAMP) detection system was developed and applied to pathogen detection. The system is compact and portable, with good uniformity and reproducibility, and it can detect pathogens rapidly and effectively. For norovirus detection, the linear range was 10⁰–10⁶ copies/μL. The system can achieve the theoretical sensitivity of LAMP detection, conclusions could be obtained within 35 min, and quantitative detection was possible. The test results of 45 clinical samples were consistent with quantitative PCR (qPCR) and clinical results, and the accuracy could reach 100%. This system has the characteristics of portability, speed, and POCT accuracy, and the cost is much lower than that of commercial qPCR. Therefore, it is suitable for remote areas or places with relatively poor conditions and environments requiring on-site conditions. It can also be widely used to detect various epidemics and unexpected diseases.

Research progress on detection techniques for point-of-care testing of foodborne pathogens

The global burden of foodborne disease is enormous and foodborne pathogens are the leading cause of human illnesses. The detection of foodborne pathogenic bacteria has become a research hotspot in recent years. Rapid detection methods based on immunoassay, molecular biology, microfluidic chip, metabolism, biosensor, and mass spectrometry have developed rapidly and become the main methods for the detection of foodborne pathogens. This study reviewed a variety of rapid detection methods in recent years. The research advances are introduced based on the above technical methods for the rapid detection of foodborne pathogenic bacteria. The study also discusses the limitations of existing methods and their advantages and future development direction, to form an overall understanding of the detection methods, and for point-of-care testing (POCT) applications to accurately and rapidly diagnose and control diseases.

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.

The Molecular Mechanism of Long Non-Coding RNA (LncRNA) Regulation of Notch Signaling in Glucose-Induced Apoptosis of Human Retinal Vascular Endothelial Cell

Diabetes, a global health concern, affects the health of more than 500 million adults. The absence of Notch protein can cause an imbalance in the retinal vascular environment and cause retinal vascular disease. Long noncoding RNA (lncRNA) is known to be involved in the regulation of many signaling pathways. We hope to understand the specific mechanism of apoptosis in retinal vascular endothelial cells (RVECs) by exploring the regulatory effect of lncRNA on the Notch pathway. In this study, we found that RVECs treated with glucose showed increased levels of Notch transcript and protein expression. The lentiviral interference with Notch RNAi reversed this response. When Notch activity decreased, oxidative stress also decreased, accompanied by increased levels of Caspase-9 and Caspase-3 and an increased rate of apoptosis. Therefore, we believe that Notch is involved in the development of diabetic retinopathy and loss of expression promotes apoptosis of human RVECs. By inhibiting the Notch pathway, lncRNA promotes apoptosis of human RVECs in a high-glucose environment.

Spherical nucleic acids: Organized nucleotide aggregates as versatile nanomedicine

Spherical nucleic acids (SNAs) are composed of a nanoparticle core and a layer of densely arranged oligonucleotide shells. After the first report of SNA by Mirkin and coworkers in 1996, it has created a significant interest by offering new possibilities in the field of gene and drug delivery. The controlled aggregation of oligonucleotides on the surface of organic/inorganic nanoparticles improves the delivery of genes and nucleic acid-based drugs and alters and regulates the biological profiles of the nanoparticle core within living organisms. Here in this review, we present an overview of the recent progress of SNAs that has speeded up their biomedical application and their potential transition to clinical use. We start with introducing the concept and characteristics of SNAs as drug/gene delivery systems and highlight recent efforts of bioengineering SNA by imaging and treatmenting various diseases. Finally, we discuss potential challenges and opportunities of SNAs, their ongoing clinical trials, and future translation, and how they may affect the current landscape of clinical practices. We hope that this review will update our current understanding of SNA, organized oligonucleotide aggregates, for disease diagnosis and treatment.

Fos-Related Antigen 1 May Cause Wnt-Fzd Signaling Pathway-Related Nephroblastoma in Children

This study aimed to investigate the role of the primary Fos-related antigen 1 (Fosl-1) oncogene in nephroblastoma by studying 60 childhood nephroblastoma and 58 paraneoplastic carcinoma cases. The Fosl-1 expression was detected using immunohistochemistry. In vitro culture of nephroblastoma cells was performed by viral transfection to establish Fosl-1 overexpression and gene knockout models. Flow cytometry and nano-PCR were used to detect apoptosis and mRNA expression in related pathway genes. Immunohistochemical results showed that the positive expression of Fosl-1 in the nuclei of nephroblastoma tissue was 78%, among which metastasis rate was 61.7%; correspondingly, it was 8%, and 100% in adjacent tissues. The qPCR results indicated that MMP9, Wnt1, and Fzd1 were significantly upregulated after Fosl-1 overexpression compared with the normal embryonic tissue cells, control, and gene knockout groups (P <0.05). Fosl-1 could cause the occurrence, development, and metastasis of childhood nephroblastoma through wingless/int1/Frizzled-related signaling pathways.

Prostate-Specific Membrane Antigen-1-Mediated Au@SiO₂@Au Core-Shell Nanoparticles: Targeting Prostate Cancer to Enhance Photothermal Therapy and Fluorescence Imaging

The advantages of deep tissue penetration and the high spatial accuracy of photothermal therapy have been widely studied. Gold, as a photothermal material, has received particular attention. Different sizes and shapes of gold have been studied and characterized for their varying photothermal properties. The core-shell structure of gold nanoparticles and silica enhances the photothermal conversion through the coupling effect between gold clusters on the material's surface. With excellent photothermal conversion performance, the core-shell nanoparticles can quickly reach 40 °C in 200 s under the irradiation of 808 nm, 1.5 W·cm^-2. The highest conversion temperature of these nanoparticles is 56 °C, and the photothermal conversion rate is 45%. In vitro cell experiments displayed that NPs with targeted function can efficiently aggregate in prostate cancer cells and effectively kill cells. In vitro experiments showed that the tumor cells of mice after photothermal treatment completely disappeared after 15 days, which fully demonstrated the potential of the nanoparticles for targeted photothermal therapy.

Detection of Chymotrypsin Using Peptide Sensor Based on Graphene Oxide Modified with Sulfhydryl Group and Gold Nanoparticles

In this study, GO modified with sulfhydryl group was prepared by thiolation on the surface of GO, which makes a meaningful material. GO with sulfhydryl group combined with gold nanoparticles,...

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.

[ARTICLE WITHDRAWN] Semiconducting Polymer Dot-Based Ratiometric Fluorescence Nanoprobe for DNA Detection

THIS ARTICLE WAS WITHDRAWN BY THE PUBLISHER IN MAY 2021

Early Diagnosis of Occult Blood of Colorectal Cancer Based on Nano-Colloidal Gold Sandwich Immunochromatography

The development of science and technology has deepened people's understanding of cancer, changing the management of malignant tumors in the medical field. Given the common precancerous characteristics of colorectal cancer (CRC), researchers studied early CRC screening. The complexity of traditional diagnostics forced medical staff to speed up CRC innovation early screening methods. Here, we prepared nano-colloidal gold raw materials with different particle sizes (15 and 30 nm) and observed the morphological characteristics and properties of the materials. Simultaneously, the nanocolloidal gold double antibody sandwich kit was designed through the optimum pH value and protein content screening experiment. The results of clinical enteroscopy confirmed the important guiding significance of the equipment in early CRC screening.

Nano-Gold PCR in Detection of TERT Methylation and Its Correlation with Hepatitis B-Related Hepatocellular Carcinoma

This study aimed to introduce nano-gold PCR for detection of TERT methylation, and explore the correlation between TERT methylation and prognosis of hepatocellular carcinoma (HCC). From March 2016 to March 2018, 154 HBV carriers treated in our hospital were enrolled in the study and divided into HCC (68 cases), cirrhosis (45 cases) and chronic hepatitis (CH) groups (41 cases) based on clinical disease. HCC patients were further divided into methylation (30 cases) and non-methylation (38 cases) subgroup based on methylation status of the TERT. TERT methylation of HCC specimens were 44.12% and 35.24% by nano-PCR and conventional PCR, respectively. The TERT methylation and TERT expression in HCC specimens were higher than for cirrhosis and CH specimens. A significant positive correlation was observed between TERT methylation and TERT expression. AFP, Edmondson classification, tumor size, hilar lymph node and intrahepatic metastasis, and TNM staging in the methylation group were higher than in non-methylation group. Further, overall survival and progression-free survival were significantly shorter. Nano-gold PCR is more sensitive in detecting TERT methylation. As CHB progresses, TERT methylation increases. Greater methylation of the gene is associated with worse prognosis in HCC patients.

Noble metal-molybdenum disulfide nanohybrids as dual fluorometric and colorimetric sensor for hepatitis B virus DNA detection

Hepatitis B virus (HBV) infection is one of the global healthcare burdens, and its early diagnosis is crucial for the prevention of HBV-induced chronic hepatitis, liver fibrosis, cirrhosis, and hepatocellular carcinoma. Although different detection approaches have been reported, most of these methods either rely on sophisticated machines or procedures, which limit their use particularly in the high endemic, developing countries. In this work, we report a dual-sensing nanoplatform built on noble metal-molybdenum disulfide (MoS₂) nanohybrids, and this platform can detect the HBV DNA target through either fluorometric or colorimetric readouts. The design with the silver nanocluster (AgNC)-MoS₂ nanohybrid enables multiplex fluorescent detection, while the HBV DNA-regulated growth of platinum nanoparticles (PtNPs) on the MoS₂ nanosheets offers signal-on colorimetric detection. Both AgNC-MoS₂ and PtNP-MoS₂ nanohybrids show high sensitivity with pico-molar detection limit and single nucleotide specificity, even with the spiked human serum. Collectively, the proposed nanohybrids possess their potential in the use of early HBV diagnosis, particularly suitable for the high endemic areas with limited medical and instrumental supports.

Preventive effect of tetrahedral framework nucleic acids on bisphosphonate-related osteonecrosis of the jaw

Zoledronic acid (ZA) is a bisphosphonate (BP) drug that has been widely used in clinical treatments as a potent bone resorption inhibitor. In recent years, an increasing number of cases of bisphosphonate-associated osteonecrosis of the jaw (BRONJ) have been reported. This is a severe maxillofacial complication characterized clinically by bone exposure, necrosis, pain, and halitosis. Its pathogenesis is still not clear, and there is no effective clinical treatment known. Therefore, prevention of BRONJ is especially important. To provide a new research direction for the treatment of BRONJ, this study used a new tetrahedral framework nucleic acid (TFNA), which can antagonize the inhibitory effect of ZA on the differentiation and maturation of osteoclasts (OCs). In vivo and in vitro experiments showed that TFNAs at a specific concentration exhibited no cytotoxicity and could reverse the inhibition of ZA on OC differentiation and maturation, effectively inhibiting the formation of BRONJ.

Enhanced Catalytic Activity of Magnetic Bimetallic Ag-Au Nanoparticles Mediated by Surface Plasmon Resonance

We firstly discover the enhanced catalytic activity of magnetic noble metal nanoparticles mediated by surface plasmon resonance. Under light irradiation with certain wavelength, the catalytic performance of magnetic noble metal nanoparticles shows changes with different degrees and directions that are associated with the surface plasmon resonance (SPR) of the noble metal. Moreover, the coupling of silver and gold allows the catalytic performance of magnetic bimetallic Ag-Au nanoparticles to show more positive response to surface plasmon resonance. The magnetic bimetallic Ag-Au nanoparticles show excellent catalytic performance toward the reduction reaction of aromatic nitro group, and corresponding rate constant of the catalytic reduction reaction increases about three times with light irradiation.

Gold Nanomaterials as a Promising Integrated Tool for Diagnosis and Treatment of Pathogenic Infections-A Review

This review summarizes research on functionalized gold nanomaterials as pathogen detection sensors and pathogen elimination integrated tools. After presenting the challenge of current severe threat from pathogenic bacteria and the increasingly serious growth rate of drug resistance, the first section mainly introduces the conspectus of gold nanostructures from synthesis, characterization, physicochemical properties and applications of gold nanomaterials. The next section deals with gold nanomaterials-based pathogen detection sensors such as colorimetric sensors, fluorescence sensors and Surface-Enhanced Raman Scattering sensors. We then discuss strategies based on gold nanomaterials for eliminating pathogenic infections, such as the dual sterilization strategy for grafting gold nanomaterials with antibacterial substances, photothermal antibacterial and photodynamic antibacterial methods. The fourth part briefly introduces the comprehensive strategy for diagnosis and sterilization of pathogen infection based on gold nanomaterials, such as the diagnosis and treatment strategy for pathogen infection using Roman signals real-time monitoring and photothermal sterilization. A concluding section that summarizes the current status and challenges of the novel diagnosis and treatment integrated strategy for pathogenic infections, gives an outlook on potential future perspectives.

Boronic acid-engineered gold nanoparticles for cytosolic protein delivery

Boronic acid-engineered gold nanoparticles for effective cytosolic protein delivery with the help of hypertonicity.