One of the main research areas in the Putnam lab is the development of polymers to assist in human health. Artificial lubricants are especially important for use in joints for treatment of osteoarthritis. Our lab, with the assistance of our collaborators in BME and the Hospital for Special Surgery in New York City, has developed a polymer capable of binding the surface of cartilage in joints and acting as a cushion during high-impact activities. The polymer was inspired by the naturally occurring joint lubricant called lubricin, which begins to decline after traumatic injury to a joint. As can be seen in the image below (left), the polymer is divided into two halves: a binding block, and a lubrication block. Our studies have shown that a low coefficient of friction results from the synergy between the two blocks, and not from each piece alone (right). This polymer is in clinical trials, and further bench studies focus on modifying the structure of the binding blocks, including the number of domains in each segment, to determine the effects on coefficient of friction and film thickness.
(A) Schematic representation of lubricin. (B) Synthetic diblock copolymer mimetic of lubricin showing the molecular compositions that mimic the functional domains of lubricin
The lubricin–mimetic diblock copolymer significantly decreases COF of articular cartilage compared with samples treated with PBS, binding block only, or lubrication block only (*P < 0.0001).
Another polymer project in the lab is directed toward treatment of dry eye disease. Dry eye disease results from not producing enough tears, or when tears evaporate too quickly, resulting in a breakup of the tear film covering the eye. Current treatments for dry eye disease are lacking in robustness, as they only provide artificial tears, requiring the patient to administer the eye drops when necessary, rather than treating the underlying condition. Our lab is currently developing a polymer capable of preventing the break down of the tear film, allowing the eye to maintain the film and reducing the number of eye drop applications necessary for the patient.