Graduate Research and Discovery Symposium (GRADS)


Coating Orthopedic Implants with an Epoxy Based PH Sensitive Layer to Image PH Changes on Implant Surface through Tissue Using X-ray Excited Luminescence Chemical Imaging

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Implant-associated infection is a leading cause of fixation failures and is often challenging to detect due to lack of symptoms and specific tests to detect localized infection. Low pH is believed to be associated with infection as bacteria and inflammatory responses cause a pH drop in the affected area. Previously we have developed a pH sensitive coating to detect these pH changes and thus indicate infection but it has been challenging to completely cover the implant surface using this coating. Herein we introduce a method to coat the entire orthopedic plate using an epoxy based coating. First step is to coat the orthopedic plate with a mixture of epoxy and scintillator particles followed by dip coating the hydrogel containing a pH dye and polymerizing under ultraviolet light. Epoxy helps to adhere the pH sensitive layer to the implant’s surface without problems of peeling off. The epoxy embedded scintillators act as an in situ X-ray excited light source emitting red light and the pH doped polymer layer differentially absorbs the scintillator emission depending on the pH. These changes in pH were noninvasively imaged using X-ray Excited Luminescence Chemical Imaging through the tissue. In future, we plan to study the pH changes on the device surface during infection and antibiotic treatment in animal models.

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