# Quality of platelet concentrates after three‐day storage following 265 nm ultraviolet C‐light‐emitting diode irradiation

## TL;DR

This study shows that irradiating platelet concentrates with 265 nm UVC-LED light reduces bacterial contamination and maintains platelet quality during storage.

## Contribution

The study demonstrates that 265 nm UVC-LED irradiation preserves platelet quality while reducing bacterial contamination.

## Key findings

- UVC-LED irradiation reduced S. aureus and B. cereus colonies by 1.7 and 1.2 log, respectively.
- Platelet count dropped to 80% of control levels after irradiation but remained stable during storage.
- Biochemical profiles and activation markers showed minimal changes after irradiation and storage.

## Abstract

We aimed to investigate the quality of platelets after storage following irradiation with ultraviolet C (UVC) light‐emitting diodes (LED).

Controlling transfusion‐related infections, particularly bacterial contamination of platelet concentrates (PCs), is urgently required. UVC‐LEDs have attracted considerable attention as potential solutions to this problem.

PCs (5.5 mL) were irradiated with 265 nm UVC‐LED for up to 60 min and then stored at 22°C with shaking for 3 days. PC quality parameters, such as platelet count, biochemical profiles, including electrolytes and metabolism, activation markers and platelet aggregability, were analysed before and after storage. Prior to the storage study, to validate the appropriateness of the UVC‐LED dose used, the PCs were inoculated with Staphylococcus aureus or Bacillus cereus, and their colony‐forming ability was evaluated after irradiation with the same dose of UVC‐LED.

We confirmed that S. aureus and B. cereus colonies decreased with the irradiation dose (by 1.7 log and 1.2 log at 38.7 and 40.4 mJ cm−2, respectively). Platelet count decreased immediately after 60‐minute irradiation to 32.5 mJ cm−2, reaching approximately 80% of the level in the control without irradiation, but no further decrease was recorded after storage. The biochemical profiles and activation markers showed little alterations.

These results indicate that UVC‐irradiated platelets maintain sufficient quality for practical use even after storage. Although this was a bench‐scale study, our findings suggest that irradiation of PCs with 265 nm UVC‐LED may enhance the safety of blood transfusions while preserving their efficacy.