Casein-Conjugated Gold Nanoparticles for Amperometric Detection of Leishmania infantum

Abstract

Sensitive and reliable approaches targeting the detection of Leishmania are critical for effective early diagnosis and treatment of leishmaniasis. In this frame, this paper describes a rapid quantification assay to detect Leishmania parasites based on the combination of the electrocatalytic ability of gold nanoparticles (AuNPs) to act as a catalyst for the hydrogen formation reaction along with the specificity of the interaction between casein and the major surface protease of the Leishmania parasite, GP63. First, pure and casein-modified AuNPs were prepared and characterized by scanning electron microscopy and ultraviolet–visible spectroscopy. Then, casein-conjugated AuNPs were incubated with Leishsmania parasites in solution; the formed complex was collected by centrifugation, treated by acidic solution, and the pelleted AuNPs were placed on screen-printed carbon electrodes (SPCEs) and chronoamperometric measurements were carried out. Our results suggest that it is possible to detect Leishmania parasites, with a limit less than 1 parasite/mL. A linear response over a wide concentration interval, ranging from 2 × 10−2 to 2 × 105 parasites/mL, was achieved. Additionally, a pretreatment of Leishmania parasites with Amphotericin B, diminished their interaction with casein. This findings and methodology are very useful for drug efficacy assessment.

Detection of Chymotrypsin by Optical and Acoustic Methods

“…The SPR absorbance of AuNPs depends on the surrounding medium and on the distance between nanoparticles [15]. In the work by Diouani, AuNPs modified with casein were used to detect Leishmania infantum using amperometric methods [16]. Chen et al modified AuNPs with a trypsin-specific peptide sequence [17].…”

Gestión de los residuos sólidos en áreas rurales, un análisis de una parroquia de la amazonia ecuatoriana

“…21 Los criterios normativos reglamentarios a nivel nacional sobre los residuos sólidos (Art. 586, Reglamento CODA), establecen las fases de la gestión integral de residuos y desechos sólidos no peligrosos como el conjunto de actividades técnicas y operativas de la gestión integral de residuos y desechos sólidos no peligrosos que incluye: a) Separación en la fuente; b) Almacenamiento temporal; c) Barrido y limpieza; d) Recolección; e) Transporte; f) Acopio y/o transferencia; g) Aprovechamiento; h) Tratamiento; y, i) Disposición final [34].…”

Novel Electrochemical Biosensing for Detection of Neglected Tropical Parasites of Animal Origin: Recent Advances

“…Casein functaionalized gold nanoparticles were used to pull down the parasite and the resultant Leishmania@casein@GNP complex is applied over the screen printed carbon electrode (SPCE) and the hydrogen evolution was measured by chronoamperometric approach. The new test was able to detect 0.55 parasite/ml with a linear range from 2 × 10 2 to 2 × 10 5 parasite/ml [41]. An alternate impedimetric biosensor was developed using the peptide based probe of promastigote surface antigen (PSA-38S).…”