# Ghost Cells as a Two‐Phase Blood Analog Fluid —Fluorescent Mechanical Hemolysis Detection

## TL;DR

This study introduces a new method using fluorescent detection to identify mechanical hemolysis in blood pumps, offering a more precise alternative to standard tests.

## Contribution

The first use of fluorescent hemolysis detection for localizing mechanical hemolysis in circulatory support systems.

## Key findings

- Fluorescence intensity increased with mechanical hemolysis at 3500 rpm and 2.5 L/min.
- Local hemolysis was visualized at the rotor tip using fluorescence image processing.
- The method was validated using both porcine blood and a two-phase blood analog fluid.

## Abstract

This study investigated fluorescent hemolysis detection as an optical method to detect local hemolysis in mechanical circulatory support systems, addressing the limitations of standard hemolysis tests and current simulation methods. Standard tests, per ASTM1841‐19, quantify general hemolysis but do not localize it.

We employ a two‐phase blood analog fluid composed of calcium‐loaded ghost cells and phosphate‐buffered saline. Ghost cells are hemoglobin‐depleted red blood cells, allowing for optical measurements. A calcium‐sensitive fluorescent indicator (Cal590 potassium salt, AAT Bioquest, Pleasanton, USA), activated by calcium released upon ghost cell hemolysis, enables fluorescent hemolysis detection. Hemolysis tests were conducted using porcine whole blood and the blood analog fluid, confirming that both undergo mechanical hemolysis in the Food and Drug Administration pump model.

The results revealed increased fluorescence intensity in response to hemolysis, with a quantitative fluorescence increase of 8.85/min at 3500 rpm and 2.5 L/min, indicating hemolysis, particularly at the rotor tip. Through image processing of fluorescence images, local hemolysis was visualized.

This study is the first to use fluorescent hemolysis detection for local detection of mechanical hemolysis. Further refinement may enhance the design of mechanical circulatory support systems and bridge simulation limitations with experimental, localized hemolysis detection.

Hemolysis is locally resolved in the Food and Drug Administration pump model within an experimental particle image velocimetry setup with the use of ghost cells as a two‐phase blood analog fluid.