Since the heart is such a del­i­cate and crit­ical organ, clin­i­cians usu­ally opt not to inter­vene with the dead cells that remain after a heart attack or car­diac dis­ease. “But we think that all heart attacks deserve some kind of treat­ment because it puts so much stress on the rest of the heart,” said Thomas Web­ster, pro­fessor and chair of the Depart­ment of Chem­ical Engi­neering. Even a square cen­timeter of dead heart tissue can put sig­nif­i­cant strain on the rest of the heart, which has to pick up the slack, he said.

Webster’s ear­lier work demon­strated that adding nanofea­tures to an implanted med­ical device like a tita­nium knee or hip joint helps the car­ti­lage cells adhere to the device. This pro­motes tissue growth and allows the patient to heal more readily, he explained. While his team mem­bers don’t know exactly why this hap­pens, they have a good idea. They think the nanofea­tures allow the sur­face to more accu­rately mimic the nat­ural envi­ron­ment in the body, thus pro­viding more hab­it­able accom­mo­da­tions for the new cells.

But tita­nium hearts aren’t a viable option. Instead, they uti­lized a hydrogel, which they’d devel­oped pre­vi­ously, to mimic the heart cells them­selves. They added carbon nan­otubes to the hydrogel, making it con­duc­tive, and then injected the mate­rial into the heart, where it solid­i­fies at body tem­per­a­ture. Because the hydrogel is “super sticky,” it adheres extremely well to the tissue sur­face and imme­di­ately begins expanding and con­tracting in sync with the beating of the heart. While the team hasn’t yet tested the mate­rial in an animal model, it has sim­u­lated these con­di­tions in the lab.

Once again, by mim­ic­king the nat­ural envi­ron­ment, they saw “improved ability of car­diomy­ocytes  [car­diac muscle cells] to attach, to pro­lif­erate, and then to secrete the chem­i­cals they secrete during normal, healthy heart func­tion,” Web­ster said. They also saw better blood vessel pro­duc­tion. Fur­ther, the mate­rial seemed to dampen the func­tion of fibrob­last cells, which are formed in scar tissue. Since scar tissue is thick and inflex­ible, it is not par­tic­u­larly well suited for the heart, which is con­stantly changing shape, Web­ster said.

We think we’ve gone as far as we can in vitro, per­fecting it hope­fully every step of the way,” Web­ster said.