‘NANOROBOTS’ KILL CAN­CER IN MICE

Cus­tom-de­signed DNA nanorobots have been suc­cess­fully used to shrink tu­mours

BBC Earth (Asia) - - Front Page -

In a world first, re­searchers from Ari­zona State Univer­sity and the Chi­nese Academy of Sciences in Bei­jing have used DNA

‘nanorobots’ to kill can­cer­ous cells by cut­ting off their blood sup­ply.

“We have de­vel­oped the first fully au­ton­o­mous, DNA ro­botic sys­tem for a very pre­cise drug de­sign and tar­geted can­cer ther­apy,” said Prof Hao Yan. “More­over, this tech­nol­ogy is a strat­egy that can be used for many types of can­cer, since all solid tu­mour­feed­ing blood ves­sels are es­sen­tially the same.”

The nanobots were made from flat, rec­tan­gu­lar DNA sheets, 90 x 60nm in size. Throm­bin, a blood-clot­ting en­zyme, was at­tached to the sur­face. When de­liv­ered to the sur­face of a tu­mour, throm­bin clots the blood within the ves­sels that feed the tu­mour, stems the blood flow, and kills the can­cer­ous tis­sue.

Another sub­stance, called a DNA ap­tamer, was then at­tached to the nanorobots’ sur­faces. When an ap­tamer comes into con­tact with a can­cer­ous growth, it binds with nu­cle­olin, a pro­tein found on the sur­face of tu­mours and not on healthy cells, al­low­ing the bot to de­liver the throm­bin.

“WE HAVE DE­VEL­OPED

THE FIRST FULLY AU­TON­O­MOUS,

DNA RO­BOTIC SYS­TEM FOR A VERY PRE­CISE DRUG DE­SIGN AND

TAR­GETED CAN­CER THER­APY”

When given to a mouse that had been in­jected with hu­man can­cer cells, the bots trav­elled through­out the blood­stream, homed in on the tu­mours, and be­gan work­ing within hours.

Of the eight mice treated for melanoma, three showed com­plete re­gres­sion of the tu­mours and the me­dian sur­vival time was dou­bled to 45 days. The team also tried the tech­nique on breast, ovar­ian and lung can­cers.

“I think we are much closer to real, prac­ti­cal med­i­cal ap­pli­ca­tions of the tech­nol­ogy,” said Yan. “Com­bi­na­tions of dif­fer­ent ra­tion­ally de­signed nanorobots car­ry­ing var­i­ous agents may help to ac­com­plish the ul­ti­mate goal of can­cer re­search: the erad­i­ca­tion of solid tu­mours. Fur­ther­more, the cur­rent strat­egy may be de­vel­oped as a drug de­liv­ery plat­form for the treat­ment of other dis­eases by mod­i­fi­ca­tion of the ge­om­e­try of the nanos­truc­tures, the tar­get­ing groups and the loaded car­goes,” he added.

Artist’s im­pres­sionof nanorobots

Artist’s im­pres­sion of nanobots (blue) at­tack­ing a can­cer­ous cell (green)

DNA ap­tamers on the nanobots at­tach to can­cer­ous cells, en­abling the bots to de­liver their lethal pay­load to a can­cer­ous tu­mourThrom­bin pay­loadDNA ap­tamer

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