A universal biomembrane adhesive developed at the University of British Columbia (UBC) could have applications in tissue engineering, drug delivery or wound care.
Phophatidyl choline (PC) is found in the phospholipids that make up cell membranes in all higher plants and animals. Choline is positively charged, while phosphate is negatively charged. A few years ago, a team of researchers led by Don Brooks, who is cross-appointed to both chemistry and medicine at UBC, hit on the idea of using the reverse group — choline phosphate (CP) — to make molecules stick to membranes. Their 2012 paper in Nature Materials described a polymer made of hyperbranched polyglycerol (HPG) and decorated with CP groups. They worked well, but there was room for improvement. “HPGs are basically spherical and the way we put the CP groups on meant you would get some in the interior,” says Brooks. By contrast, a linear polymer would keep all the CP groups on the outside, free to interact with cell membranes.
The team’s latest paper in Chemical Communications describes the creation of 2-(methacryloyloxy)ethyl choline phosphate (MCP) and its successful polymerization into poly(MCP). The new material shows adhesion that is strong yet gentle. “Polymers like polylysine are just as strong, but they rip the membranes apart,” says Brooks. “These ones don’t.” He says that while any individual PC-CP bond isn’t that strong, it’s their high number and availability at the surface that lead to good adhesion.
Because cells can easily draw in molecules stuck to their surface, the new material could see application as a drug delivery agent. However, Brooks says the first application out of the gate will likely be as a tissue sealant. “We’re working on that right now,” he says. “I think we should have something useful to talk about within 18 months or so.”