Spray-printing piezoresistive sensors based on poly (D, L-lactide-co-glycolide) copolymer composites for urinary catheter applications

Abstract

There is an increasing demand for new and improved methods for treating chronic diseases, such as Hinman syndrome or non-neurogenic bladder. Typically, a procedure called Clean Intermittent Catheterization (CIC) is performed, which removes urine by inserting a urinary catheter into the urethra to relieve pressure on the bladder and prevent kidney damage. The placement of piezoresistive sensors in the urinary catheter can be used to optimize the insertion path during the procedure by monitoring the catheter's deformation along the urethra. In considering this, a sustainable approach is implemented for the development of biodegradable and biocompatible piezoresistive sensors based on the natural polymer Poly(D,L-lactide-co-glycolide) (PDLG) with different contents of multiwalled carbon nanotubes (MWCNTs) up to 5 wt.%. Their mechanical, electrical, thermal, morphological, and piezoresistive functional responses have been assessed. The electrical percolation threshold occurs for the MWCNT content of 1 wt.% and the maximum piezoresistive response is characterized by a gauge factor (GF) of ∼1.5 for the same composite. The composite with 1 wt.% MWCNT content was spray-printed onto the urinary catheter and the proof-of-concept implied the evaluation of the piezoresistive response of the sensor as a function of the catheter's deformation angle. The developed spray-printed piezoresistive sensors demonstrated suitable electrical, mechanical, and piezoresistive properties, offering an environmentally friendly and sustainable approach for the development of this type of biomedical device.