Media Releases

DNA-built nanstructures safely target, image cancer tumors

February 5, 2014

TORONTO, ON –  A team of researchers at the Uni­ver­si­ty of Toron­to has dis­cov­ered a method of assem­bling “build­ing blocks” of gold nanopar­ti­cles as the vehi­cle to deliv­er can­cer med­ica­tions or can­cer-iden­ti­fy­ing mark­ers direct­ly into can­cer­ous tumors. The study, led by War­ren Chan, Pro­fes­sor at the Insti­tute of Bio­ma­te­ri­als & Bio­med­ical Engi­neer­ing (IBBME) and the Don­nel­ly Cen­tre for Cel­lu­lar & Bio­mol­e­c­u­lar Research (CCBR), appears in an arti­cle in Nature Nan­otech­nol­o­gy this week.

“To get mate­ri­als into a tumor they need to be a cer­tain size,” explains Chan. “Tumors are char­ac­ter­ized by leaky ves­sels with holes rough­ly 50 – 500 nanome­ters in size, depend­ing on the tumor type and stage. The goal is to deliv­er par­ti­cles small enough to get through the holes and ‘hang out’ in the tumor’s space for the par­ti­cles to treat or image the can­cer. If par­ti­cle is too large, it can’t get in, but if the par­ti­cle is too small, it leaves the tumor very quick­ly.”

Chan and his researchers solved this prob­lem by cre­at­ing mod­u­lar struc­tures ‘glued’ togeth­er with DNA. “We’re using a ‘mol­e­c­u­lar assem­bly’ mod­el — tak­ing pieces of mate­ri­als that we can now fab­ri­cate accu­rate­ly and orga­niz­ing them into pre­cise archi­tec­tures, like putting LEGO blocks togeth­er,” cites Leo Chou, a 5^th year PhD stu­dent at IBBME and first author of the paper. Chou was award­ed a 2012–13 Cana­di­an Breast Can­cer Foun­da­tion Ontario Region Fel­low­ship for his work with nan­otech­nol­o­gy.

“The major advan­tage of this design strat­e­gy is that it is high­ly mod­u­lar, which allows you to ‘swap’ com­po­nents in and out. This makes it very easy to cre­ate sys­tems with mul­ti­ple func­tions, or screen a large library of nanos­truc­tures for desir­able bio­log­i­cal behav­iors,” he states.

The long-term risk of tox­i­c­i­ty from par­ti­cles that remain in the body, how­ev­er, has been a seri­ous chal­lenge to nanomed­ical research.

“Imag­ine you’re a can­cer patient in your 30s,” describes Chan. “And you’ve had mul­ti­ple injec­tions of these met­al par­ti­cles. By the time you’re in your mid-40s these are like­ly to be retained in your sys­tem and could poten­tial­ly cause oth­er prob­lems.”

DNA, though, is flex­i­ble, and over time, the body’s nat­ur­al enzymes cause the DNA to degrade, and the assem­blage breaks apart. The body then elim­i­nates the small­er par­ti­cles safe­ly and eas­i­ly.

But while the researchers are excit­ed about this break­through, Chan cau­tions that a great deal more needs to be known.

“We need to under­stand how DNA design influ­ences the sta­bil­i­ty of things, and how a lack of sta­bil­i­ty might be help­ful or not,” he argues.

“The use of assem­bly to build com­plex and smart nan­otech­nol­o­gy for can­cer appli­ca­tions is still in the very prim­i­tive stage of devel­op­ment. Still, it is very excit­ing to be able to see and test the dif­fer­ent nano-con­fig­u­ra­tions for can­cer appli­ca­tions,” Chan adds.

The project was fund­ed by CIHR, NSERC, CBCF, and CFI.

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ABOUT IBBME

The Insti­tute of Bio­ma­te­ri­als and Bio­med­ical Engi­neer­ing (IBBME) is a cut­ting-edge inter­dis­ci­pli­nary unit sit­u­at­ed between three Fac­ul­ties at the Uni­ver­si­ty of Toron­to: Applied Sci­ence and Engi­neer­ing, Den­tistry and Med­i­cine. The Insti­tute pur­sues research in four areas: neur­al, sen­so­ry sys­tems and reha­bil­i­ta­tion engi­neer­ing; bio­ma­te­ri­als, tis­sue engi­neer­ing and regen­er­a­tive med­i­cine; mol­e­c­u­lar imag­ing and bio­med­ical nan­otech­nol­o­gy; med­ical devices and clin­i­cal tech­nolo­gies.

Media con­tact:

Erin Vol­lick
Senior Com­mu­ni­ca­tions, Media and Alum­ni Rela­tions Offi­cer
Insti­tute of Bio­ma­te­ri­als and Bio­med­ical Engi­neer­ing (IBBME)
E: comm.ibbme@utoronto.ca
C: (416) 946‑8019
W: www.ibbme.utoronto.ca