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Tuberculosis (TB), a human and animal disease caused by Mycobacterium tuberculosis (M.tb), has the highest global mortality rate after coronavirus disease 2019 (COVID-19) and poses a major public health threat to China and several countries worldwide. Since 1890, vaccine candidates for various forms of TB have been developed for different age groups, but these vaccine candidates have not provided good protection in adolescents and adults in clinical trials. To help prevent and control the spread of TB, the development of a safe and effective TB vaccine is important. Studies conducted in recent years have shown that MTB39A has good immunogenicity and that the baculovirus expression vector systems have promising applications in vaccine development. Accordingly, in this study, we expressed the MTB39A protein via an insect-baculovirus surface display expression system, and the obtained recombinant baculovirus surface-displayed particles were used as subunit vaccines for the immunization of BALB/c mice. The results showed that the rvAc-71cA/rvAc-MTB39A recombinant baculovirus surface-displayed particles exhibited good immunogenicity in mice and could be considered potential candidates for further development of more effective genetically engineered vaccines based on the MTB39A protein, providing a solid experimental foundation for the further development of vaccines against TB and for the development of vaccines for other associated diseases using the baculovirus expression system.

Insertions/deletions (indels) variations have been recognized as a promising marker for the development of various diseases. However, methods used for the genotyping of indels in studies were tedious, complicated, and required sophisticated or expensive instruments, as well as complex data analysis, which makes it difficult to meet the demand of point of care testing. Herein, we presented a fast and accurate biosensor (T-ARMS-PCR-LFA) by the combination of tetra-primer amplification refractory mutation system polymerase chain reaction (T-ARMS-PCR) and GoldMag lateral flow assay (LFA) for visual genotyping of

Rapid and simple detection of single nucleotide polymorphism (SNP) is vital for individualized diagnosis and eventual treatment in the current clinical setting. In this study, we developed a tetra-primer ARMS-PCR combined lateral flow assay (T-ARMS-PCR-LFA) method for simultaneous visual detection of two alleles. By using four primers labeled with digoxin, biotin and Cy5 separately in one PCR reaction, the amplified allele-specific products could be captured by streptavidin and the anti-Cy5 antibody on two separated test lines of a LFA strip, which allows the presentation of both alleles within the single LFA strip. Both DNA and whole blood can be used as templates in this genotyping method in which the whole detection process is completed within 75 minutes. The performance assay of T-ARMS-PCR-LFA demonstrates the accuracy, specificity and sensitivity of this method. One hundred human whole blood samples were used for MTHFR C677T genotyping in T-ARMS-PCR-LFA. The concordance rate of the results detected was up to 100% when compared with that of the sequencing results. Collectively, this newly developed method is highly applicable for SNP screening in clinical practices.

Tumorigenesis driven by abnormal DNA methylation has highlighted the need to develop a portable, rapid and sensitive strategy for accurate methylation detection with a specific cancer-prognostic gene, which caters to the popularization of precision medicine. In this study, a site-specific biosensor for both visual and magnetic DNA methylation determination has been established based on lateral flow assay. By introducing digoxin- and biotin-labeled primers into PCR, the amplicons can be recognized and captured by gold magnetic nanoparticles (GMNPs) in this biosensor. Working as a signal probe, the optical property of GMNPs allows the amplicons to be interpreted with naked eyes avoiding any complex equipment and cumbersome operation after PCR. Moreover, by virtue of the magnetic property of GMNP, the signal can be explained and recorded by a magnetometer in clinical practice. The introduction of tailor-made primer sets makes it possible to accurately distinguish 0.1% methylated variants in the presence of numerous unmethylated variants as strong interferential background and vice versa at target cytosine-guanine dinucleotide. A distinct signal can be observed with as low as 0.01 pg variants for both visual and magnetic analyses. As a significant tumor suppressor gene, the promoter methylation status of miR-34a is accurately determined with not only cell lines but also with clinical samples, which demonstrates the great potential of this biosensor for cancer diagnosis and prognosis.

Deletion mutation has been proved as the important factor for occurrence and development of disease, especially those with cancer. With the popularity of precision medicine, the individual cancer therapeutic strategy has highlighted the requirement to develop a straightforward and competent strategy for deletion mutation determination. Hence, the present study is dedicated to develop a one-step assay to identify deletion mutation with sequence specificity for clinical practice. Taking advantage of loop-mediated isothermal amplification, an ultrasensitive and rapid deletion mutation determination method is established, which allow as low as 30 copies or 0.1% target variants under strong interferential background can be accurately distinguished in 30 min dispensing with professional operation and complex data interpretation. As a demonstration, the epidermal growth factor receptor p.E746-A750del, a crucial factor for the susceptibility of tyrosine kinase inhibitor in non-small-cell lung cancer treatment, has been accurately identified by this method with both cell lines and real clinical samples. By tailor-made primer set, this method can be extended for other deletion mutants, making it a molecular diagnostic tool and could be readily adapted for cancer diagnosis, therapy and prognosis in point of care diagnostic test scenario.

The aberration in DNA methylation pattern has been proved as a promising biomarker for early cancer diagnosis, prognosis and therapy from clinical perspective. In the era of precision medicine, current technologies for DNA methylation identification require not only professional and time-consuming operation but also sophisticated apparatus and complex data interpretation, which has highlighted the need to develop a straightforward and competent strategy for DNA methylation detection. Therefore, the present research is dedicated to establish a novel biosensor by integrating of loop-mediated isothermal amplification (LAMP) and lateral flow device (LFD) to identify trace of DNA methylation from highly heterogeneous cancerous specimen. In order to resolve the natural contradiction between sensitivity and specificity in nucleic acid amplification-based detection methods, we introduce the biotin labeled inner primer and digoxigenin labeled dUTP into LAMP-LFD for the first time, which allow this biosensor to identify as low as 150 copies or 0.1 % target variants under strong interferential background within 35 min after bisulfite conversion. Furthermore, the gold magnetic nanoparticle serving as a signal generator in LFD enables the result to be interpreted through both visual and magnetic detection. The promoter methylation pattern of miR-34a, a significant tumor suppressor gene, has been investigated using LAMP-LFD with cell lines and clinical samples, which indicate that this biosensor may be readily adapted for detection of other DNA methylation biomarkers as a sensitive screening tool for cancer diagnosis.

In this work, we theoretically analyze the performance characteristics of a near-field thermophotovoltaic system consisting a Mie-metamaterial emitter and GaSb-based photovoltaic cell at separations less than the thermal wavelength. The emitter consists of a tungsten nanoparticle-embedded thin film of SiO 2 deposited on bulk tungsten. Numerical results presented here are obtained using formulae derived from dyadic Green’s function formalism and Maxwell–Garnett-Mie theory. We show that via the inclusion of tungsten nanoparticles, the thin layer of SiO 2 acts like an effective medium that enhances selective radiative heat transfer for the photons above the band gap of GaSb. We analyze thermophotovoltaic (TPV) performance for various volume fractions of tungsten nanoparticles and thicknesses of SiO 2 .

Single-nucleotide polymorphisms (SNPs) represent the most widespread type of genetic variation (approximately 90%) in the human genome, and the demand to overcome such variation has received more attention now than ever before. The capacity to rapidly assess SNPs that correlate with disease predisposition, drug efficacy and drug toxicity is a key step for the development of personalized medicine. In this work, a rapid one-step SNP detection method, real-time loop-mediated isothermal amplification (RT-LAMP), was first applied for CYP2C19 polymorphisms testing. The optimized method was established with specifically designed primers for target amplification by real-time detection in approximately 30 min under isothermal conditions. RT-LAMP amplified few copies of template to produce significant amounts of product and quantitatively detected human DNA with compatible specificity and sensitivity. The success in the establishment of this RT-LAMP protocol for CYP2C19 polymorphism testing is significant for the extension of this technique for the detection of other SNPs, which will further facilitate the development of personalized medicine.

Current techniques for single nucleotide polymorphism (SNP) detection require tedious experimental procedures and expensive and sophisticated instruments. In this study, a visual genotyping method has been successfully established via combining ARMS-PCR with gold magnetic nanoparticle (GoldMag)-based lateral flow assay (LFA) and applied to the genotyping of methylenetetrahydrofolate reductase (MTHFR) C677T. C677T substitution of the gene MTHFR leads to an increased risk of diseases. The genotyping result is easily achievable by visual observation within 5 minutes after loading of the PCR products onto the LFA device. The system is able to accurately assess a broad detection range of initial starting genomic DNA amounts from 5 ng to 1200 ng per test sample. The limit of detection reaches 5 ng. Furthermore, our PCR-LFA system was applied to clinical trials for screening 1721 individuals for the C677T genotypes. The concordance rate of the genotyping results detected by PCR-LFA was up to 99.6% when compared with the sequencing results. Collectively, our PCR-LFA has been proven to be rapid, accurate, sensitive, and inexpensive. This new method is highly applicable for C677T SNP screening in laboratories and clinical practices. More promisingly, it could also be extended to the detection of SNPs of other genes.

We theoretically analyze two near-field thermal rectification devices: a radiative thermal diode and a thermal transistor that utilize a phase change material to achieve dynamic control over heat flow by exploiting metal-insulator transition of VO2 near 341 K. The thermal analogue of electronic diode allows high heat flow in one direction while it restricts the heat flow when the polarity of temperature gradient is reversed. We show that with the introduction of 1-D rectangular grating, thermal rectification is dramatically enhanced in the near-field due to reduced tunneling of surface waves across the interfaces for negative polarity. The radiative thermal transistor also works around phase transition temperature of VO2 and controls heat flow. We demonstrate a transistor-like behavior wherein heat flow across the source and the drain can be greatly varied by making a small change in gate temperature.