In this study, we developed a flexible wearable phototheranostic patch integrating a red organic light-emitting diode (OLED) and an organic photodiode (OPD) with a hydrocolloid dressing. The platform enables photobiomodulation (PBM) using a 630 nm red OLED together with photoplethysmographic (PPG) sensing through an adjacent OPD. The hydrocolloid provides low elastic modulus and high conformability while maintaining mechanical and optical stability under repeated bending. To coordinate optical therapy and sensing, the OLED was operated using pulse-width modulation (PWM) at 50 Hz with a 30 % duty cycle. PPG measurements showed that PWM maintained clear signal acquisition at reduced time-averaged irradiance, with SNR generally increasing as the PWM ON-state irradiance increased. Among the tested PWM conditions, PWM-16.67 exhibited the strongest overall cell-proliferative response and the highest SNR, while delivering approximately the same radiant exposure as the DC reference. Notably, PWM-10 also achieved a cell-proliferative response comparable to the DC reference while reducing radiant exposure by 40 %, indicating its potential as a lower-exposure operating condition. Thermal measurements further showed that PWM reduced heat accumulation relative to continuous DC operation at matched peak irradiance, although this thermal advantage was partially diminished as the higher ON-state current required for increased PWM irradiance introduced additional thermal load. These results demonstrate the feasibility of integrating optical therapy and physiological sensing within a single conformable hydrocolloid-based OLED–OPD platform and provide a basis for further development of wearable wound phototheranostic systems.

Wearable electroceuticals are emerging as a key platform for health management due to their safety and non-invasiveness, with therapeutic efficacy enhanced by close skin contact. In this study, we present a wearable organic light-emitting diode (OLED) patch that integrates flexible hardware and a flexible battery for self-operation and reusability. The OLED exhibits excellent mechanical flexibility, adhering intimately to the skin while maintaining a safe temperature range of 20 °C at 5 mW/cm², stable operation for over 1000 h, and high moisture resistance. Daily irradiation with 632 nm OLED light (9 J/cm²) in mouse models of psoriasis and atopic dermatitis (AD) led to significant recovery of epidermal thickness and transepidermal water loss (TEWL) to near-normal levels. The expression of inflammatory cytokines (IL-4, IL-17, and IL-22) also tended to be suppressed. These results suggest that wearable OLED-based phototherapy can complement the limitations of existing treatments and offer a self-administered treatment strategy.

Advancements in technology have led to a diversification of wound treatment methods, offering new possibilities for enhancing patient care. Though laser and light-emitting diodes (LEDs) phototherapy are common, they are challenged for their downsides such as rigidity, bulkiness and overheating. However, organic light-emitting diodes (OLEDs) are recently in the limelight as a method of phototherapy that overcomes the existing shortcomings. A variety of wearable OLEDs have been developed using plastic substrates. These can provide phototherapy, but are not suitable for use in wounds where ooze forms. In this study, we report a platform combining OLEDs and hydrocolloid that accelerates wound healing, absorbs ooze, provides a moist environment to wound, and improves skin adhesion. This platform utilizes a proprietary planarization method to reduce the root-mean-square roughness (R_q) value to 0.844 nm, and the luminescence performance of the device is also at the same level as that of a glass substrate device. In addition, we confirmed in-vitro cell proliferation effect of up to 160% at a luminous intensity of 5 mW/cm², and experimentally demonstrated the moisture retention ability of hydrocolloid-based OLEDs for wounds in a pig skin model. This suggests that we have created an ehanced wound care platform.