The liver is one of the vital organs needed for human survival. It is the only organ that can regenerate, if a portion of it was harvested from live donor (LD) or deceased donors (DD). For any successful liver transplant (LT), the degree of macrovesicular steatosis (MS) (i.e, accumulation of fat in liver cells) is intimately related to the viability of liver graft in post-LT outcomes. So it is important to diagnose MS in the pre-DDLT or LDLT setting. An ideal liver graft should have no MS, however, upto 60% MS is accepted and above 60% MS will be rejected for LT. Ideally, the gold standard liver biopsy is performed to quantify the MS in every liver graft. However, it is time-consuming, invasive, and logistically challenging in poor resource conditions, especially in the DDLT setting. This results in the liver grafts being subjectively/qualitatively evaluated by the organ retrieving surgeon.
In this context, we developed a handheld device that quantitatively assesses the MS using the principle of diffuse reflectance spectroscopy, where the fat-specific wavelength in the infrared region has been considered. As a proof of concept, the developed device was tested in animal liver and 100% fat, and also in LDLT having less than 10% of fat and 100% fat from omentum (visceral lipids). The device was also validated with agar-based liver phantom with varying fat content between 10 to 70%. The obtained results from LDLT as well as liver phantoms are promising towards the diagnosis of MS. Hence, we propose that our device would be a valuable tool for real-time MS quantification in the DDLT settings. In addition to this, post LT diagnosis also needs attention in determining the patient's survival of post-LT. Here, the elevation of ammonia in the blood leads to early diagnosis of graft rejection. In this regard, an improved version of U-bent fiber optic sensor (U-FOS) probe was developed by wet-chemical etching and tested for various biochemical sensing as a proof of concept. Further, metal organic framework modified U-FOS probes, will be established for ammonia sensing in serum/breath for the early diagnosis of graft rejection in post-LT.