Using nanomaterials to carry drug molecules to specific cells in the body is a relatively new field in healthcare research. But it’s an important one.
For example, in order to target therapies to tumors, scientists have developed techniques to attach drug molecules (or vaccines) to nanomaterials like graphene sheets, a single-atom-thick sheet of carbon that is stronger than steel and as stiff as diamond. These “Trojan horse” nanotherapies can bring drugs directly to tumors, where they can be released onto cancer cells to, in theory, fight the disease.
A movie on the molecular scale shows how an uncoated graphene nanosheet interacts with an E. coli outer cell membrane.
The Soft Matter Science department in IBM Research’s Healthcare and Life Sciences group is working to develop new techniques and approaches to understanding this increasingly important field for disease research.
Scientists know that unless you attach “coating molecules” such as polyethyelne glycol (a linear polymer) to graphene sheets, their bare surfaces and sharp edges can inadvertently damage surrounding cells. Attaching polymers to graphene sheets makes them more biocompatible.
What we didn’t know is that these polymer-coated graphene sheets have an inadvertent effect on the human immune system. Our team recently discovered that polymer-coated nanomaterials trigger a dramatic reaction in the body’s cells — one that we previously didn’t see.
This zoomed-in image shows how a graphene sheet (grey) directly delivers its nanodrug (white, red and blue) to a cell’s wall (yellow and red).
Cells can communicate with each other, sending signals to other types of cells. In a recent healthcare research paper published in Nature Communications, we discovered that these polymer-coated graphene sheets trigger an emergency response in the body’s immune system. Simply put, your cells sense that there’s a foreign body (the nanomaterial) and release “signal flares” (in the form of proteins called cytokines). These signal flares attract the body’s immune cells — like helper T cells (which relay the signal forward) and killer T cells (which, as their name suggests, kill infected cells) to the location of the graphene sheets. Simulations on IBM’s Blue Gene supercomputer showed that the polymers “glue” the nanomaterials to cell surfaces, which amplifies the initial signaling process. The healthcare research also suggests that these signals are broadcast within six hours of the nanodrugs being encountered.
Polymer-coated graphene sheets aren’t necessarily harmful to human beings, which is partially why scientists hadn’t discovered this accidental impact until now. Your cells are basically crying wolf whenever they detect polymer-covered nanomaterials nearby; immune cells simply respond to the call and travel to the sites of polymer-coated cells.
We’ve essentially uncovered a new way to trigger the body’s immune cells to spring into action, which is not an easy task. Without causing physical damage, polymer-coated graphene sheets incite cells into shooting off signal flares that bring the teeth of the immune system to bear at whatever location in the body the nanodrugs are delivered.
This discovery could represent an incredible development in precision medicine. If these nanomaterials were targeted at, say, tumors or virus-infected cells, one could, in principle, stimulate the immune system to attack cancer and infections at their source.
Immunotherapies like this might also be coupled to the delivery of traditional drugs, which we already know can be attached to graphene surfaces. Coupling both the body’s own natural immune system with nano or traditional pharmaceuticals could form the basis for new ways in which human diseases are fought.