Synthetic Platelets Developed for Therapies, Diagnostics

Nishit Doshi (UC Santa Barbara)

Chemical engineers at University of California-Santa Barbara, with colleagues at Scripps Research Institute and Sanford-Burnham Institute in La Jolla, California, have developed synthetic blood platelets for therapeutic and diagnostic uses. Their findings appear online in the journal Advanced Materials (paid subscription required).

The team led by research scientist Nishit Doshi (pictured right), now with a private biotechnology company, took on the task of developing a synthetic platelet comparable in size — 2 to 4 micrometers — but with the same structural properties. Those physical and biochemical properties of platelets allow blood to prevent excessive bleeding and to heal wounds.

The researchers started with materials made of chemical polymers. “In order to mimic the size, shape, and surface functionality of natural platelets synthetically, polymeric particles are particularly attractive,” says Doshi. “However, polymeric particles are orders of magnitude more rigid than platelets.”

The UC Santa Barbara team addressed the issue of rigidity by building a polymeric core, around which they deposited and cross-linked layers of proteins and polyelectrolytes to create a stable synthetic platelet-shaped particle. The researchers then dissolved the rigid polymeric core to give the particle the desired flexibility. Using a process developed at Scripps Research Institute, the team then added a coating with proteins found on the surface of activated natural platelets or damaged blood vessels.

The synthetic platelets devised by the UC Santa Barbara team can do more than replace natural platelets. The new platelets can also deliver drugs to dissolve blood clots or carry imaging agents to identify damaged blood vessels. Clotting factors and platelets from outside donors are often used to halt bleeding, but they can trigger immune system responses and thrombosis in some cases. Likewise, substitutes other than platelets do not resemble the physical features of natural platelets.

Frank Doyle, director of UC Santa Barbara’s Institute of Collaborative Biotechnologies calls the work “a marvelous demonstration of the power of material synthesis applied to medical problems.” Doyle adds that “synthetic platelets can have profound implications in wound-healing problems for trauma and wounds arising in both battlefield situations and during surgery.”

Read more:

• Hopkins to Study Creating Blood Platelets from Stem Cells
• Diagnostics Company Gets State Grant for Blood Platelet Test

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