Immunosensor based on magnetic nanoparticles applied for the early detection of galactomannans in human serum samples

GERMÁN A. MESSINA; SOFÍA V, PIGUILLEM; MARTÍN A. FERNÁNDEZ BALDO; JULIO RABA

Buenos Aires

Jornada; XX Jornadas Anuales de la Sociedad Argentina de Biología (SAB)-XVII Jornadas de la Sociedad Uruguaya de Biociencias (SUB), Segundas Jornadas Rioplatenses de Biología.CABA,; 2018

SOCIEDAD ARGENTINA DE BIOLOGÍA

Galactomannan (GMN) is a polysaccharide cell-wall component that is released by Aspergillus species. Invasive aspergillosis (IA) is a human infection caused by a kind mold called Aspergillus fumigatus. This mold often has been found in dead leaves, decomposing vegetal matter and organic fertilizer. The symptomatology of this disease can be non-specific, it can cause cough, pleuritic pain, fever and usually presents with pleural effusion. When this infection go to the brain can cause seizures, stroke, meningitis and it can be fatal. GMN is a biomarker of medical interest because it is find in patients´s blood with IA disease. The purpose of this work was the development of an immunosensor able to detect GMN in early stages of this disease. Therefore, cobalt ferrite (CoFe2O4) nanoparticles covered with APTMS ((3-Aminopropyl)trimethoxysilane) were synthesized, characterized and used as immobilization platform of monoclonal anti-GMN antibodies in a microfluidic immunosensor. The concentration of captured GMN was then detected with laser-induced fluorescence (LIF) using a system of HRP-conjugated anti-GMN-antibody. The HRP catalyzed the oxidation of nonfluorescent 10-acetil-3,7-dihidrofenoxacina (ADHP) to highly fluorescent resorufin, which was measured by LIF detector, using excitation lambda at 561 nm and emission at 585 nm, in the presence of oxygenated water. The detection limits (LODs) calculated for LIF detection and for a commercial enzyme-linked immunosorbent assay (ELISA) test kit were 0.08 and 1 ng mL-1, respectively. The within- and between-assay variation coefficients for the LIF detection procedure were below 6.5%. This microfluidic immunosensor can be applied to the early diagnosis of IA because it offers several attractive advantages as hight stabilized, hight selectivity and sensibility due to immobilization of monoclonal antibodies in CoFe2O4 utilized as nano-platform of bioaffinity.