Molecular diagnosis of α-thalassemias by the colorimetric nanogold

Abstract

A new application of gold nanoparticles (AuNPs) as a colorimetric method for gene detection of athalassemia 1 (SEA deletion) is reported here for the first time. This technique is based on color changes from salt-induced aggregation of un-hybridized nanogold probes after hybridization with the target DNA. Specific DNA probes were synthesized, thiol modified and conjugated on the surface of AuNPs.The target DNA was amplified and hybridized with the AuNPs-immobilized probe. Salt solution (NaCl) was added to induce aggregation of the un-hybridized nanogold probes. The color changes were visualized either by the naked eye or by UV-vis spectrophotometry at 520 nm. By this nanogold colorimetric method samples carrying normal a-globin genes could be successfully identified from samples carrying a-globin genes causing a-thalassemia 1 (SEA deletion), either as a carrier or disease form. Results demonstrated that the new colorimetric nanogold method is a definite gene diagnosis of a-thalassemia. It is accurate, simple, rapid, specific, sensitive, and cost effective. It is also a promising point-of-care testing (POCT) method for thalassemias and other genetic disorders. The new colorimetric nanogold is a method of choice for areas where access to sophisticated molecular diagnosis is limited.

Development of a Highly Sensitive Loop-Mediated Isothermal Amplification Incorporated with Flocculation of Carbon Particles for Rapid On-Site Diagnosis of Blood Disease Bacterium Banana

“…Besides agarose gel electrophoresis, a variety of colour-based methods have been developed. One such method involves adding gold nanoparticles (AuNP) with covalently attached probes to the completed reaction, which causes the colour of the AuNPs to change in the presence of the specific amplicon [23][24][25][26][27][28][29]. In an alternative technique, the DNA intercalating fluorescent dye SYBR Green I is added to the reaction, which turns the solution orange in the absence of DNA amplification and yellow/green in the presence of amplified DNA [23,[30][31][32].…”

Rapid visual detection of Mycobacterium tuberculosis DNA using gold nanoparticles

“…These GNPs were utilised for further experiments based on literature search. 15,18 The data for the synthesis of other sizes of GNPs have been presented in the ESI † of this manuscript.…”

A simple, robust and equipment-free DNA amplification readout in less than 30 seconds

“…9 Numerous color based methods have been developed for equipment-free visualization of DNA amplication; in one approach, gold nanoparticles (AuNP) with covalently attached probes can added to the completed reaction to produce a color change in the presence of the specic amplicon. [10][11][12][13][14][15] In a different approach, the DNA intercalating uorescent dye SYBR Green I is added to the reaction turning the solution orange in the absence of DNA amplication and yellow/green in the presence of amplied DNA. [16][17][18] However, to achieve a strong difference between the positive and negative DNA amplications, a high concentration of SYBR needs to be added aer the amplication is nished as it would otherwise inhibit the reaction.…”