Single nucleotide polymorphisms (SNPs) are closely related to genetic diseases, but current SNP detection methods, such as DNA microarrays that include tedious procedures and expensive, sophisticated instruments, are unable to perform rapid SNPs detection in clinical practice, especially for those multiple SNPs related to genetic diseases. In this study, we report a sensitive, low cost, and easy-to-use point-of-care testing (POCT) system formed by combining amplification refractory mutation system (ARMS) polymerase chain reaction with gold magnetic nanoparticles (GMNPs) and lateral flow assay (LFA) noted as the ARMS-LFA system, which allow us to use a uniform condition for multiple SNPs detection simultaneously. The genotyping results can be explained by a magnetic reader automatically or through visual interpretation according to the captured GMNPs probes on the test and control lines of the LFA device. The high sensitivity (the detection limit of 0.04 pg/μL with plasmid) and specificity of this testing system were found through genotyping seven pathogenic SNPs in phenylalanine hydroxylase gene ( PAH, the etiological factor of phenylketonuria). This system can also be applied in DNA quantification with a linear range from 0.02 to 2 pg/μL of plasmid. Furthermore, this ARMS-LFA system was applied to clinical trials for screening the seven pathogenic SNPs in PAH of 23 families including 69 individuals. The concordance rate of the genotyping results detected by the ARMS-LFA system was up to 97.8% compared with the DNA sequencing results. This method is a very promising POCT in the detection of multiple SNPs caused by genetic diseases.

Genotyping of single nucleotide polymorphisms (SNPs) in point-of-care (POC) settings could be further improved through simplifying the treatment of samples. In this study, we devised an accurate, rapid and easy-to-use SNP detection system based on direct loop-mediated isothermal amplification (LAMP) without DNA extraction, known as Direct-LAMP. Samples from various sources (including whole blood, dried blood spot, buccal swab and saliva), treated with NaOH, can be used directly in amplification. The turnaround time was about 30 min from sample collection to provision of results. The accuracy was evaluated by assessing the polymorphisms of methylenetetrahydrofolate reductase (MTHFR) C677T and aldehyde dehydrogenase-2 (ALDH2) Glu504Lys, which are better known for their critical role in folate and ethanol metabolism, respectively. Completely consistent genotyping results reveal that Direct-LAMP is generally concordant with sequencing. This system can serve as a very promising platform in the fields of disease predisposition, drug metabolism and personalized medicine.

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Linoleic acid was isolated effectively from Sambucus williamsii (SW) seed oil which was extracted by high-pressure fluid and its biological activities were investigated. Linoleic acid was isolated from the oil by urea inclusion, the yield was 65.81% and the purity was 92.12%. 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay was used to determine the antioxidant activity of linoleic acid. IC 50 of DPPH radical scavenging activity of linoleic acid was 61.92 mg/mL. The antiglycemic activity of linoleic acid was evaluated by determining its inhibitory effect on α-glucosidase. The results showed that α-glucosidase was inhibited to a certain extent by linoleic acid (1.56-25 mg/mL). In addition, the hypolipidemic activity of linoleic acid was investigated in vivo using hyperlipidemia mice models fed with the linoleic acid at doses of 1, 2, 4 g/kg BW (body weight). The results showed that serum lipid levels were highly significantly (p < 0.01) improved, which indicated the hypolipidemic activity of linoleic acid. The linoleic acid extracted from SW seed oil was proved to possess good antioxidant, antiglycemic and hypolipidemic activity in human diets, which may have industrial use.

SummaryDeveloping a sensitive, low-cost, and easy-to-use point-of-care testing system for genotyping is important for informing treatment decisions and predicting the risk of underlying diseases. Conventional methods normally require complex operational procedures as well as expensive and sophisticated instruments. Here, we report a general approach that enables us to detect the genotype of multiple sample types directly without DNA purification. Moreover, the PCR results can be further quantitatively analyzed based on a magnetic lateral flow assay (MLFA) system, which avoids multiple steps needed for conventional nucleic acid biosensors. As a demonstration, we show that three genotypes of aldehyde dehydrogenase 2 (ALDH2) can be identified using a small volume of sample with an accuracy of 100% and a sensitivity of 1.0 × 102 cells/μL, which are better than those of the gold standard methods. We believe that the direct PCR-MLFA system represents a significant advance toward the development of portable, sensitive biomedical platforms.