Scientists at Northwestern University have been working on a technology that utilizes nanostructures, called nanodiamonds, to humorally transport and deliver insulin molecules to wounds. It has been postulated that insulin can help wounds heal faster, by enhancing local area angiogenesis. By noting that burn wound sites can have a more basic pH level (unlike infected wounds that are acidic), the researchers were able to attach insulin to nanodiamond particles so that it is released in a basic environment, delivering the drug where its needed.
A substantial amount of insulin can be loaded onto the nanodiamonds, which have a high surface area. The nanodiamond-insulin clusters, by releasing insulin in alkaline wound areas, could accelerate the healing process and decrease the incidence of infection. Ho says this ability to release therapeutics from the nanodiamonds on demand represents an exciting strategy towards enhancing the specificity of wound treatment.
In their studies, Ho and his colleagues showed that the insulin was very tightly bound to the nanodiamonds when in an aqueous solution near the normal physiological pH level. Measurements of insulin function revealed that the protein was virtually inactive when bound to the nanodiamonds — a beneficial property for preventing excess or unnecessary drug release.
Upon increasing the pH to the basic levels commonly observed in the skin during severe burns, the researchers confirmed the insulin was released from the nanodiamond clusters and retained its function. Exploiting this pH-mediated release mechanism may provide unique advantages for enhanced drug delivery methods.
The researchers also found the insulin slowly and consistently released from the nanodiamond clusters over a period of several days.
Insulin accelerates wound healing by acting as a growth hormone. It encourages skin cells to proliferate and divide, restores blood flow to the wound, suppresses inflammation and fights infection. Earlier investigations have confirmed an increase in alkalinity of wound tissue, due to bacterial colonization, to levels as high as pH 10.5, the pH level that promoted insulin release from the nanodiamonds in the Northwestern study.
Press release: Nanodiamonds Deliver Insulin for Wound Healing…
Abstract in Biomaterials: Nanodiamond-insulin complexes as pH-dependent protein delivery vehicles…
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