Rapid, objective intraoperative mapping of Hirschsprung disease with a portable electrochemical acetylcholine sensor

Surgical procedures for bowel aganglionosis require accurate identification of enteric ganglion cells and cholinergic nerve hypertrophy. Current intraoperative mapping through frozen section histopathology-histochemistry is time-consuming and demands skilled interpretation. This study explores an electrochemical sensor for objective, rapid intraoperative mapping of the aganglionic bowel segment via tissue acetylcholine (ACh) detection.

An electrochemical biosensor was developed using nanostructured electrodes functionalized with acetylcholinesterase(AChE) and choline oxidase (ChOx) enzyme hybrids. Electrochemical analyses were conducted on homogenized intestinal biopsies obtained intraoperatively from ten patients, including eight diagnosed with Hirschsprung Disease (HSCR) and two with total colonic aganglionosis (TCA). Biopsy samples representing ganglionic, transitional, and aganglionic bowel segments were evaluated. The sensor quantified tissue ACh levels, a surrogate marker of cholinergic neuronal hypertrophy, by measuring the generated electrical current.

The electrochemical analysis demonstrated significantly higher current levels in the aganglionic segments compared to ganglionic segments in 87.5% (7 out of 8) of HSCR patients. The mean peak currents observed in HSCR cases were 2.62 µA in aganglionic segments, 3.66 µA in transition segments, and 2.04 µA in ganglionic segments. In contrast, electrochemical patterns in patients diagnosed with TCA were atypical; ileal tissue samples from these patients generally yielded higher current measurements than colonic samples across all zones examined. Additionally, there was a progressive increase in tissue current values correlating positively with patient age.

The electrochemical sensor effectively differentiated aganglionic from ganglionic zones in HSCR, suggesting its potential as a quick, objective tool for intraoperative bowel levelling. Further validation in larger cohorts is necessary to confirm the clinical utility.