Skin-Contact Wearables Made from Photopolymers: Occlusion, Sweat, Friction, Sensitisation and Long-Term Use

A skin-contact wearable made by vat photopolymerisation is a device-skin system, not merely a cured material. Occlusion changes hydration and barrier function; sweat changes ionic strength, pH and transport; motion produces friction, pressure and microclimate cycling; cleaning and ageing modify the surface; and residual or newly generated constituents can create irritation or sensitisation hazards. A one- time material assay under dry, static conditions therefore cannot qualify prolonged or repeated wear. This review defines a risk-based architecture for qualifying photopolymer wearables in their finished, clinically relevant use state. It freezes the print, wash, cure, finish, cleaning and ageing configuration; maps anatomical contact, duty cycle and vulnerable populations; separates irritation from sensitisation; combines chemical characterisation with occluded extraction and simulated-sweat exposure; and evaluates pressure, shear, roughness, moisture accumulation and mechanical durability as interacting but non-interchangeable evidence. Non-compensatory gates prevent favourable cytotoxicity, chemistry or mechanics from masking an unresolved dermal hazard. The result is a traceable qualification plan with predefined escalation, wear-stop and change-control rules, without prescribing a universal process window or product-specific acceptance limit.

ER-255 · Version 0.4.