A final year PhD student doing research in multidisciplinary research field which applied the fundamental sciences to the real application.

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Synthesis method of gold nanoparticles Conjugation steps Sandwich assay of diagnostic assay

This project involved the comparison of the citrate reduction method versus seeded-growth method to synthesis gold colloids in nano size within ranges 5 nm to 150 nm. The properties of the gold nanoparticles at 20, 30 and 40 nm synthesized from both method were compared in term of performances as a labelling agent in lateral flow immunoassay. The assay is line with test line using a biomarker for Brugian filariasis disease and control line using polyclonal antibody: IgG. The results show 30 nm gold nanoparticles made using seeded-growth method having the best performance as a labelling agent for lateral flow immunoassay. The performance including faster detection time (less than 10 min), the most intensed line and the best sensitivity and specificity.


The effects of size and synthesis methods of gold nanoparticle-conjugated MαHIgG4 for use in an immunochromatographic strip test to detect brugian filariasis.

Abstract: This study describes the properties of colloidal gold nanoparticles (AuNPs) with sizes of 20, 30 and 40 nm, which were synthesized using citrate reduction or seeding-growth methods. Likewise, the conjugation of these AuNPs to mouse anti-human IgG(4) (MαHIgG(4)) was evaluated for an immunochromatographic (ICG) strip test to detect brugian filariasis. The morphology of the AuNPs was studied based on the degree of ellipticity (G) of the transmission electron microscopy images. The AuNPs produced using the seeding-growth method showed lower ellipticity (G ≤ 1.11) as compared with the AuNPs synthesized using the citrate reduction method (G ≤ 1.18). Zetasizer analysis showed that the AuNPs that were synthesized using the seeding-growth method were almost monodispersed with a lower polydispersity index (PDI; PDI≤0.079), as compared with the AuNPs synthesized using the citrate reduction method (PDI≤0.177). UV-visible spectroscopic analysis showed a red-shift of the absorbance spectra after the reaction with MαHIgG(4), which indicated that the AuNPs were successfully conjugated. The optimum concentration of the BmR1 recombinant antigen that was immobilized on the surface of the ICG strip on the test line was 1.0 mg ml(-1). When used with the ICG test strip assay and brugian filariasis serum samples, the conjugated AuNPs-MαHIgG(4) synthesized using the seeding-growth method had faster detection times, as compared with the AuNPs synthesized using the citrate reduction method. The 30 nm AuNPs-MαHIgG(4), with an optical density of 4 from the seeding-growth method, demonstrated the best performance for labelling ICG strips because it displayed the best sensitivity and the highest specificity when tested with serum samples from brugian filariasis patients and controls.

Pub.: 21 Nov '12, Pinned: 16 Jan '18