Wireless, Bio-Implementable Strain Gauge for Continuous Bladder Monitoring

The pressure of the bladder is critical to treat the neurogenic bladder dysfunction in the patients with myelomeningocele, where loss of bladder control can cause kidney damage, urinary tract infections, and even death. The development of semi-invasive implantable bioelectronic devices that can sense bladder pressure opens the door for a new generation of urodynamics (UDS) tools; however, long-term biocompatibility needs to be confirmed. A foreign body response (FBR)- type of chronic inflammation may contribute to the worsening of bladder dysfunction and a slowed recovery. This study phenotypes the host inflammatory response by histological and immunohistochemical characterization of FBR markers in response to a wireless bio-implantable strain gauge for continuous bladder monitoring. Mononuclear cell infiltration was evaluated by using hematoxylin and eosin (H&E) staining, while Masson’s trichrome staining was used to evaluate collagen deposition and vascular change. IHC directed against inflammatory markers: CD68 for macrophages and myeloperoxidase (MPO) for neutrophils. This is in line with our results demonstrating the strain gauge's potential for chronic implantation. Together, the results show the capabilities of the device toward chronic bladder pressure monitoring while also demonstrating that biocompatibility of the device, an important consideration for its clinical uses.