A. Anzum, S. Nelluri, A. Lewandowski, A.D. Ortega-Zambrano, A. Vazquez-Guardado
North Carolina State University,
United States
Keywords: dynamic, optical biosensing, FMN, real-time, organ, continuous
Summary:
Machine perfusion (MP) preserves organs more effectively than static cold storage by continuously circulating oxygenated, nutrient-rich solution through the tissue. This active process enhances preservation quality. Despite significant advances in organ machine preservation, there are limited solutions to monitor organ function in real-time as the basis for organ health assessment prior transplantation or as a tool to monitor organ function machine preservation research. Clinical gold standards, such as ELISA, HPLC, or PCR, are time consuming, rely on intermittent sample collection and, overall, do not provide organ health assessments in real-time. In this report we use flavin mononucleotide (FMN), released from damaged mitochondrial complex I in machine perfusion, as an endogenous biomarker for organ health. Elevated levels (>23.5 ng/mL in liver preservation) indicate early signs of organ dysfunction during machine preservation. Here we report the development of a portable fluorescence optical biosensing apparatus that supports real-time, continuous, and non-contact monitoring of FMN directly within the flow line of organ perfusion systems. The device includes a blue laser (450 nm, 35 mW), a microcontroller, and a laser power driver module to control the laser excitation parameters (50 Hz frequency and 2 ms pulse widths). Fluorescence light is coupled with an optical bandpass filter (515–530 nm) and a high-gain silicon photodetector (200 kV/A). A custom GUI interface with the controller acquires, processes, and records real-time sensor data, providing automated visualization and sensitive detection of subtle FMN fluctuations. We tested this optical biosensor in a benchtop perfusion system using 1% (wt/v) BSA aqueous solution, simulating organ perfusion media, and 1000 mL/min flow rates. Fluorescence data were summarized as mean ± SD, and the area under the curve (AUC) was calculated for each sample. This optical biosensing apparatus achieved dynamic FMN detection over the range of 4–1000 ng/mL, with a limit of detection of 4 ng/mL, about ten times smaller than onset of organ disfunction benchmark. This integrated platform offers synchronized, repeatable, non-contact sensing, high temporal resolution and robust optical detection, forming a versatile system for continuous, in-line monitoring of mitochondrial injury during organ perfusion and supporting future predictive analytics for organ viability in real-time. This work lays the foundations for developing closed-loop perfusion systems with intelligent feedback biocontrol, offering transformative potential for precision monitoring not only in organ transplantation but other dynamic systems such as dialysis and other extracorporeal support therapies.