Development and technical validation of a portable photobiomodulation patch incorporating 830 nm light-emitting diodes for postoperative scar management

Hypertrophic scars and keloids are frequent after surgery, yet preventive options suitable for early, home-based use remain limited. Near-infrared photobiomodulation (PBM) can modulate inflammation and tissue remodeling, but purpose-built portable systems for scar minimization are scarce. Aiming to address this need, a flexible 830 nm LED patch with microcontroller-based dose control was engineered in this study. Bench tests assessed emission spectrum, irradiance uniformity/stability, transmittance through dressings, and safety (IEC 60601-1 thermal; IEC 62471 photobiological). Peak emission 829.7 ± 0.2 nm; panel irradiance 7.1 ± 0.2 mW cm -2 (left) and 7.1 ± 0.2 mW cm -2 (right), stable over 15 min; skin temperatures stabilized at 38.0 ± 0.1 °C (~ 25 °C ambient) and 39.7 ± 0.2 °C (~ 31 °C), below the 43 °C per IEC 60601-1 Table 23. Transparent dressings did not materially attenuate irradiance. Photobiological evaluation supported IEC 62471 Risk Group 1 for the intended use. In summary, the 830 nm LED patch delivered uniform and stable irradiance, evaluated in accordance with IEC thermal and photobiological test methods, demonstrating engineering safety and performance feasibility.