**Background:** The postpandemic era has highlighted the importance of mobile health (mHealth) for continuous, real-time monitoring and personalized healthcare. Despite the potential of wearable devices and smartphones, the development and popularization of mHealth technology have been slower than expected. This viewpoint aims to propose ways to unleash the potential of mHealth by focusing on a paradigm shift: the 'smartphonization of wearable devices' (embedding smartphone computational power and sensor-integrated displays into wearables) and the 'wearable deviceization of smartphones' (changing smartphone form factors to attach to curved skin surfaces). The authors investigate recent trends in healthcare sensing using wearable devices and smartphones, analyze challenges, and propose solutions using new form factor displays.
**Methods:** This is a viewpoint article that reviews recent literature on mHealth technologies. The authors categorize wearable devices by body attachment location (face, upper body, limbs, whole body) and describe corresponding detection targets and form factors. They also review smartphone-based healthcare apps, categorizing them by sensing methods (CMOS, hybrid sensors, IMU/microphone, touch sensors, interlocked gadgets, display materials, and apps). The authors then discuss prospects, challenges, and breakthroughs for mHealth, focusing on sensor-integrated and new form factor displays.
**Key Results:** The review summarizes numerous wearable and smartphone-based health sensing technologies. For wearable devices, examples include: EEG measurement via head tattoos (Shin et al.), intraocular pressure sensing via contact lenses (Kim et al.), sodium intake analysis via intraoral electronics (Lee et al.), CO2 sensing inside face masks (Escobedo et al., resolution 103 ppm), voice pressure sensing via neck patch (sensitivity 5.5 V Pa^-1, Lee et al.), cardiopulmonary monitoring via epidermal patch (Rachim et al.), breathing pattern monitoring via air-silicon composite transducer (Cotur et al.), spine tracking via 5-sensor system (Stollenwerk et al.), waist circumference measurement via belt (F1-score 0.95, Nakamura et al.), multifunctional electronic skin (Hua et al.), power generation textile for cardiovascular monitoring (Zhao et al.), stand-alone organic skin patch with PPG sensor (Lee et al., 15 μm thick, stable at 30% strain), wireless graphene thermal patch (Kang et al.), motion capture device for limb movements (Liu et al.), gait analysis strap with 6 IMUs (Luo et al.), and electronic textile suit for multimodal sensing (Wicaksono et al.). For smartphones, examples include: atrial fibrillation screening via PPG using built-in camera (Chan et al.), heart rhythm analysis via CMOS sensor (Tabei et al.), blood pressure measurement via oscillometric finger-pressing method using strain gauge (Chandrasekhar et al.), spirometry via microphone (Thap et al.), pesticide evaluation via optical platform (Chu et al.), acute otitis media diagnosis via smartphone otoscope (Mousseau et al.), malaria detection via microfluidic platform (sensitivity 8 ng/mL, Ghosh et al.), antibacterial touchscreen coating (Ippili et al.), and digital phenotyping for psychiatric conditions (Chen et al.). The authors note that current mHealth faces challenges: wearable devices have low penetration rates due to dependence on smartphones, small screens, poor battery, and high cost; smartphones cannot maintain continuous skin contact for real-time monitoring. The proposed breakthrough is a sensor-integrated, flexible display that uses optical methods (since most mHealth sensors are optical), allows large-area sensing (improving detection performance), and conformally adheres to skin via pressure-sensitive adhesive (PSA) that creates new neutral planes to prevent cracks. Examples include flexible AMOLED with MoS2 backplane (Choi et al., 18×18 TFT array on 6 μm PET) and wearable display with flexible backplane (Park et al.).
**Clinical Implications:** The authors argue that the smartphonization of wearable devices and wearable deviceization of smartphones, enabled by sensor-integrated and new form factor displays, could revolutionize mHealth by providing continuous, real-time, large-area health monitoring. This would facilitate AI-based disease prediction, prevention, and treatment, and support universal health coverage. The approach could democratize healthcare, making high-quality services accessible to all socioeconomic groups. However, the authors acknowledge that advances in big data AI, medical security, and policy are also needed to ensure equitable benefits.