Anti-Biotin polyclonal antibody [Texas Red®]

Impedimetric aptasensors without signal amplification exhibit poor sensitivity for the detection of small molecule contaminants. In this work, biotinylated nanoparticles of biotin-FNPs were readily prepared by the self assembly of biotin-phenylalanine (biotin-Phe) monomers. The biotin-FNPs were then used for the development of competitive impedimetric aptasensors by streptavidin-biotin (SA-biotin) coupling chemistry. Specifically, capture of biotinylated DNA (biotin-DNA) by the aptamer-modified electrode allowed for the in situ formation of SA-biotin-FNPs networks on the electrode surface, hampering the electron transfer by creating an insulating layer. The target-aptamer interaction prevented the capture of biotin-DNA, thus inhibiting the formation of SA-biotin-FNPs networks on the electrode surface and allowing for the electron transfer. To demonstrate the analytical performances of the strategy, aflatoxin B-1 (AFB(1)) was determined as the model analyte. The aptasensor exhibited a linear range of 0.05-3 pg/mL. The detectable concentration is much lower than that achieved by other impedimetric aptasensors. The strategy may provide a general way for the design of biosensors to determine various small molecules by matching sequence-specific aptamers.

Objectives: Holocarboxylase synthetase deficiency (HCSD) (OMIM #253270) is a rare inborn error of metabolism with an estimated annual incidence of 1 in 200,000 people. Typical manifestations of HCSD include eczema, alopecia, lactic acidosis and hyperammonemia. Diagnosis is made through genetic analysis. Case presentation: Patient 1 was a 7-year-old girl with normal growth and development, presenting with severe hypoglycemia and metabolic acidosis. Her family reported that she was diagnosed as having ketotic hypoglycemia; she had five episodes of hypoglycemia and metabolic acidosis in past 4 years when her oral intake decreased during acute illness. Patient 2 was a 6-month-old female infant with normal growth and development, presenting with progressive generalized eczema and metabolic acidosis for the first time. We found that they both had hyperammonemia, hyperlactatemia, hyperketonemia, organic acids detected in urine and elevated C5OH acylcarnitine level by tandem mass spectrometry. HLCS gene analysis showed a homozygous pathogenic variant p.V363D in patient 1 and a pathogenic variant p.R508W compound with a novel splice site pathogenic variant c.2010-1G>A in patient 2. They have been on biotin treatment (10 mg/day for both of them) for more than 2 years and no more symptoms have occurred. Conclusions: HCSD is a rare disease, and it can be fatal if severe metabolic acidosis occurs without timely management. Once the diagnosis is made, most of the patients with HCSD have good prognosis and normal life expectancy with biotin treatment.