Genotyping of α-thalassemias by the colorimetric nanogold probes

• Published in: Clinica chimica acta Vol. 437; pp. 197 - 202
• Main Authors: Chomean, Sirinart, Wangmaung, Nantawan, Sritongkham, Pornpimol, Promptmas, Chamras, Ittarat, Wanida
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2014
• Subjects: alpha-Thalassemia - diagnosis; alpha-Thalassemia - genetics; Colorimetry - methods; DNA Probes - genetics; Gene Targeting - methods; Genotype; Gold; gold nanoparticles; Humans; Metal Nanoparticles; nanogold probe; thalassemia genotyping; α-thalassemias; α-thalassemias; thalassemia genotyping; gold nanoparticles; nanogold probe
• ISSN: 0009-8981; 1873-3492
• DOI: 10.1016/j.cca.2014.07.033

The novel colorimetric nanogold probe was created to genotype subgroups of the mostly found α-thalassemias. They are α-thalassemia 1 (SEA and THAI deletion) and α-thalassemia 2 (3.7-kb and 4.2-kb deletion). The genotyping was performed by two-steps hybridizations. First step was hybridization of target DNA with the nanogold mixed probes of either α-thalassemia 1 or α-thalassemia 2. No hybridization in both reactions showing blue color indicated absence of abnormal genes causing these α-thalassemias. Positive reaction showing either red or purple color was further analyzed in second hybridization with the nanogold single probe. Positive of α-thalassemia 1 was genotyped with the single probes of both SEA and THAI deletion while those of α-thalassemia 2 were genotyped with both 3.7-kb and 4.2-kb deletion. Genotypic potency of the nanogold mixed and single probes was evaluated using both known diagnosed and suspected clinical samples. The results by naked eye were consistence with those analyzed by standard agarose gel electrophoresis. Potency of the colorimetric nanogold α-thalassemia probes was accurate, precise, sensitive, specific, simple, cheap and field applicable. Color reaction was simply visualized by naked eye. This development is an example of colorimetric molecular diagnosis which can be applied in any genetic detection. •Nanogold α-thalassemic probes could differentially diagnose and genotype α-thalassemia 1 and α-thalassemia 2 by naked eye.•Discriminative power of color detection was clearly seen by naked eye.•It is sensitive, specific, accurate and cost effective.•It is field applicable and is a promising thalassemia point of care testing.