Liver transplant is a surgical procedure in which a diseased or damaged liver is replaced with a healthy liver from a live or deceased donor. It is critical to analyze the fat content of the liver prior to transplantation because it correlates with poor post-liver transplant (LT) outcomes. Fat is classified as mild (≤30%), moderate (30-60%), or severe (>60%), based on the percentage of fat occupied in a single liver cell. Severe fat content in the liver precludes transplantation because it may result in early graft failure (EGF). Conventional invasive liver biopsy and several non-invasive techniques like CT, MRI, ultrasound, and nuclear imaging are currently being followed in clinical settings. However, due to time constraints and the subjective nature of pathologists, biopsy-based detection often fails, especially when it comes to brain dead donors (BDD). To address this problem, a hand-held device for fat quantification by the surgeons during the surgical procedures was designed and developed. This device works on the diffused reflectance spectroscopy principle, quantifying the fat content in a tissue based on the absorption of Infrared light due to the vibrational excitation in molecular groups. The developed device was tested for fat content in live and deceased donors at Rela Hospital, Chennai, India and St. James University Hospital, Leeds, UK. About 49 patients with different fat percentages 0 - 5% (17), 10 - 15% (18), 20 - 30% (12), 30 - 40% (1), and 40 - 50% (1) were tested. The device showed 91.3% sensitivity when compared to the gold standard biopsy.
In post-LT, the detection of ammonia for the EGF is a major challenge to monitor prognosis. To address this, optical quantitative detection technologies offer ease-of-assessment in bedside monitoring. In this direction, a metal-organic framework (MOF) coated fiber optic sensor (FOS) for ammonia detection was designed and developed. MOF crystals were coated by a wet chemical method on the geometrically modified U-bent FOS for trapping the ammonia when it is subjected to biological fluid samples. The developed sensor has been calibrated from the concentration range of 5 to 580 µmol/L with a sensitivity and detection limit of 1.228 e-7 ΔI / log ([NH3] in µmol/L) and 5.22 µmol/L, respectively. A compact LED-photodetector based handheld device was developed, thereby demonstrating the potential for bedside assessment of ammonia in post-LT.