Rapid diagnosis of acute myocardial infarction based on reverse transcription-accelerated strand exchange amplification of miR-208a.

Acute myocardial infarction (AMI) is a prevalent cardiovascular disease associated with high morbidity and mortality, posing a significant threat to human health. Therefore, early diagnosis of AMI has become a focal point of research. MiR-208 is specifically expressed in the heart and is involved in the regulation of cardiomyocyte hypertrophy, cardiac fibrosis, and other myocardial gene expressions. It is expected to be applied in the clinical detection of AMI due to its release by damaged myocardial cells within 3 hours of AMI. In this study, we developed a denatured bubble-mediated reverse transcription-accelerated strand exchange amplification (RT-ASEA) method to detect the early biomarker miR-208a of AMI. The novel approach allowed rapid amplification of miR-208a in 15 minutes, with good performance in terms of repeatability (CV < 6%), determination limit (1 × 100 pmol L-1), and linearity (R2 = 0.9690). Based on the analysis of 42 clinical samples, a strong correlation was observed between the Ct value of miR-208a detected by the RT-ASEA method and the cTnI concentration, considered the gold standard for diagnosis of AMI. The research suggested that the RT-ASEA method could be applied to distinguish between AMI and healthy groups. The area under the receiver operating characteristic curve (AUC) was 0.9976, with a sensitivity of 96% and a specificity of 100%. Optimized RT-ASEA is a reliable and efficient method for miRNA detection. Furthermore, this study provides crucial data support for the development of miR-208a as an early biomarker for AMI, which is of great significance in life and health.

In vivo animal study of the magnetic navigation system for capsule endoscope manipulation within the esophagus, stomach, and colorectum.

BACKGROUND/PURPOSES: Magnetic navigation capsule endoscopy (MNCE) is considered to be an important means to realize the controllable and precise examination of capsule endoscopy (CE) in the unstructured gastrointestinal (GI) tract. For the current magnetic navigation system (MNS), due to the limitation of workspace, driving force, and control method of the CE, only clinical application in the stomach has been realized, whereas the examination of other parts of the GI tract is still in the experimental stage. More preclinical studies are needed to achieve the multisite examination of the GI tract. METHODS: Based on the MNS (Supiee) developed in the laboratory, an X-ray imaging system with magnetic shielding and a commercial CE are integrated to form the MNCE system. Then, in vivo GI tract experiments with a porcine model are performed to verify the clinical feasibility and safety of this system. Moreover, the effects of different control modes on the efficiency and effect of GI tract examination are studied. RESULTS: Animal experiments demonstrate that with the MNCE system, it is convenient to achieve steering control in any direction and multiple reciprocating movements of CE in the GI tract. Benefiting from the flexibility of the three basic control modes, the achieved swing movement pattern of CE can effectively reduce the inspection time. It is demonstrated that the esophageal examination time can be reduced from 13.2 to 9.2 min with a maximum movement speed of 5 mm/s. CONCLUSION: In this paper, the feasibility, safety, and efficacy of the MNCE system for a one-stop examination of the in vivo GI tract (esophagus, stomach, and colorectum) is first demonstrated. In addition, complex movement patterns of CE such as the swinging are proved to effectively improve examination efficiency and disease detection rates. This study is crucial for the clinical application of the MNCE system.

Tri-primer-enhanced strand exchange amplification combined with rapid lateral flow fluorescence immunoassay to detect SARS-CoV-2.

The novel coronavirus disease 2019 caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been surging rapidly around the world, which has exposed humanity to unprecedented economic, social and health impacts. To achieve efficient and accurate detection of SARS-CoV-2 on site, we developed and verified a rapid and sensitive fluorescence lateral flow immunoassay based on the innovative enhanced strand exchange amplification (ESEA-LFIA) in this study. With good amplification efficiency for short-sequence targets, ESEA is an ideal choice for the point-of-care testing of SARS-CoV-2 with a high mutation rate. ESEA reaction can be completed in one step and verified by restriction enzyme digestion. The design consisting of three working primers greatly improved the amplification efficiency. Amplification of the target sequences of the RdRP and N genes can be accomplished under the same reaction conditions, and does not require expensive instruments. The sensitivity of the ESEA-LFIA assay targeting the RdRP and N genes was 90 copies per µL and 70 copies per µL, respectively. Specificity tests showed that the novel assay can specifically detect SARS-CoV-2, and had no cross-reactivity with 9 closely-related human pathogenic coronaviruses and other common respiratory pathogens with similar clinical manifestations. The cutoff values of the RdRP and N gene assays are 11 and 12, respectively, and the assays can be completed within 1 h. The novel strategy proposed in this study is a sensitive and specific method for the rapid detection of SARS-CoV-2, and is suitable as an effective potential bioanalytical tool to respond to future regional or global outbreaks of emerging infectious pathogens with high mutation rates.

Lateral flow fluorescent immunoassay based on isothermal amplification for rapid quantitative detection of Salmonella spp.

Salmonella spp. are zoonotic pathogens of substantial public health concern. To enable detection in the field or under instrument-free conditions, we developed a rapid and robust lateral flow fluorescent immunoassay based on strand exchange amplification (SEA-LFIA) for the quantitative detection of Salmonella spp. As far as we know, this work is the first report regarding the use of Bst DNA polymerase-assisted SEA for fluorescence sensing to detect Salmonella spp. The SEA method was further confirmed by enzymatic digestion and Sanger dideoxy sequencing. The specificity of SEA-LFIA assay was verified by 89 Salmonella strains (18 Salmonella reference strains and 71 clinical isolates) and 15 non-Salmonella reference strains (different genera). The sensitivity of SEA-LFIA assay was 6 × 100 CFU mL-1 of Salmonella pure culture or 3 × 104 CFU 25 g-1 of artificially spiked raw chicken meat. Using this assay, it was found that 37 (16%) of the 236 samples collected were positive, which was consistent with the results of conventional PCR. The cutoff value is 15 and SEA-LFIA assay only takes ∼30 min without high equipment and reagent cost. In addition, the proposed strategy can be easily extended by redesigning the corresponding amplification primers to detect target analytes. In conclusion, the optimized SEA-LFIA assay is an efficient and specific method for the detection of Salmonella spp., and can potentially serve as a new on-site diagnostic tool in life sciences.

Polymerase chain reaction combined with fluorescent lateral flow immunoassay based on magnetic purification for rapid detection of canine parvovirus 2.

BACKGROUND: Canine parvovirus 2 (CPV-2) is one of the most common etiological agents that cause severe gastroenteritis in puppies. Early accurate diagnosis is important for infected dogs. In recent years, magnetic separation has become an efficient and useful tool for bioassays. In this study, polymerase chain reaction (PCR) combined with fluorescent lateral flow immunoassay (LFIA) based on magnetic purification assay was developed for the quantitative detection of CPV-2. RESULTS: The optimum working reaction volume and reaction time for LFIA was 100 µL and 2 min, respectively. The PCR-LFIA assay only detected CPV-2, and did not show cross-detection of non-CPV strains. Experiments showed analytical sensitivity of 3 × 101 copies/µL and demonstrated the PCR-LFIA has a diagnostic agreement of 100% with conventional PCR on detection of clinical samples (22.6% positive, 14/62). Cutoff value is 146. The results were further verified by sequencing and BLAST software. The entire process from PCR step only takes ~ 80 min. CONCLUSIONS: This approach provides an attractive platform for rapid and quantitative detection of CPV-2, indicating great promise as a convenient molecular detection tool to facilitate disease outbreak investigations and response timely.

Self-Assembled Exopolysaccharide Nanoparticles for Bioremediation and Green Synthesis of Noble Metal Nanoparticles.

Continuing efforts have been made to explore novel exopolysaccharides (EPSs) for valuable applications. In this research, we report for the first time that a novel non-glucan EPS named EPS-605 can self-assemble to form spherical nanosize particles of ∼88 nm in diameter, expanding both the range of EPS type and structural type that EPSs self-assemble into. Characterization of EPS-605 shows that it is composed of mannose, glucose, and galactose with several modifications including acylation, phosphorylation, sulfation, and carboxylation, and a highly negative charge. EPS-605 showed a record biosorption capability for Pb2+, Cu2+, Cd2+, and methylene blue as compared to that of other reported EPSs, biosorbents, and nanosorbents. The adsorption ability of EPS-605 is affected by pH, temperature, the initial adsorbate concentration, the contact time, and the presence of background electrolytes. The mechanism of EPS-605 adsorbing heavy metals seems to be different to that for dyes. Moreover, EPS-605 can serve as the reductant in the synthesis of Au nanoparticles (AuNPs) and AgNPs enabling good monodispersity within the shortest time (of 30 min) compared to that from other EPSs and without any extra pretreatment. Our research advances the development of novel EPSs and provides a new, eco-friendly, and renewable platform for both the bioremediation and green synthesis of nanomaterials.