Tai­wan schol­ars in­vent pa­per based test for TB

BioSpectrum (Asia) - - Science News -

A re­search team at

Na­tional Tai­wan Univer­sity have de­vel­oped a more prac­ti­cal di­ag­nos­tic test for tu­ber­cu­lo­sis (TB) that can be read with a smart­phone. The re­searchers com­bined gold nanopar­ti­cles with sin­glestranded DNA se­quences that bind to the ge­netic ma­te­rial of My­cobac­terium tu­ber­cu­lo­sis, the bac­te­ria that cause TB. These nanopar­ti­cles were then in­cor­po­rated into a pa­per­based de­vice. By uti­liz­ing sur­face plas­mon res­o­nance ef­fect, the re­searchers were able to mon­i­tor changes in the color of a gold nanopar­ti­cle col­loid based on the ef­fects of sin­gle-stranded DNA probe mol­e­cules hy­bridiz­ing with tar­geted dou­ble-stranded TB DNA. The hy­bridiza­tion event changes the sur­face charge den­sity of the nanopar­ti­cles, caus­ing them to ag­gre­gate to var­i­ous de­grees, which mod­i­fies the color of the so­lu­tion in a man­ner that can be read­ily mea­sured to de­ter­mine the con­cen­tra­tion of the tar­geted DNA an­a­lyte.

Adding even a small amount of lab-de­rived, dou­ble-stranded DNA from M. tu­ber­cu­lo­sis changed the color of the test spots within an hour. A smart­phone cam­era was used to an­a­lyze the color change to de­ter­mine the bac­te­rial con­cen­tra­tion. The re­searchers also tested a tis­sue sam­ple from an in­fected pa­tient to fur­ther demon­strate that the de­vice could be used in the field.

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