We know that fibroin forms ultra-thin, transparent, flexible and mechanically robust films that adhere to the skin like a second layer and accommodate micro-folds, sweating and traction. These qualities, combined with biocompatibility and the possibility of modulating the β-sheet crystalline content, make it an ideal substrate for e-skin and skintronics. Literature demonstrates that fibroin-based films/composites support piezoresistive, capacitive-tactile sensors and optoelectronic platforms while maintaining breathability and surface stability.
There are wearable devices created with this silk protein that monitor pressure, deformation, temperature and biosignals with reduced drift thanks to the stability of the protein network. Various research has demonstrated that fibroin e-skin not only detects tactile stimuli, but also generates energy from humidity and contact, enabling self-powered nodes on skin. Integration with conductive materials such as graphene/rGO or vaporized metals, when deposited on fibroin films, maximizes sensitivity, with elongation limits compatible with the epidermis.
Haptic feedback. Towards organic tactility
Fibroin functions as an elastic and acoustically transmissive matrix for thin actuators, micro-heaters and low-power vibro-tactile devices. The coupling between the soft mechanics of the protein film and the printed conductive layers allows the creation of localized feedback patterns without skin irritation, with tactile resolutions compatible with rehabilitation applications and haptic guidance. The demonstration of sensitive and, in parallel, active e-skin platforms on fibroin substrates consolidates the feasibility of bidirectional sense-and-respond systems on the body.
In soft robotics, it has been seen that fibroin substrates combined with functional layers extend artificial touch to shear, sliding and micro-vibrations. The frontier is moving towards optoelectronic skins capable of detecting environmental chemical signals as well, integrating optical and electronic channels in thin membranes. The intrinsic conformability of fibroin simplifies wrapping on complex surfaces and robotic fingers without fractures occurring in the functional layers.
It is well known that the difference in elastic modulus between traditional electrodes and neural tissues is a known cause of inflammation and chronic instability. Soft platforms based on fibroin can then reduce mechanical mismatch, greatly improving anchoring, and can serve as temporary bio-resorbable supports for cortical arrays and flexible probes. Literature on bio-inspired interfaces and long-term stability strategies confirms that soft and biofunctionalized substrates attenuate micromovements, favoring signal maintenance.
From conduction to functionalization
Fibroin can be made conductive by doping with carbonaceous nanofillers, metals and conductive polymers, while preserving its protein architecture. The directionality of crystallization and control of β-sheet content allow regulation of hysteresis and stability in humid environments, with recent demonstrations of high-sensitivity devices with low mechanical noise. These strategies also enable networks for micro-heaters, radiofrequency antennas and ultra-thin optical waveguides on protein supports.
Sericin too, maintained pure and controlled in its molecular architecture, acts as a bio-adhesive and hydrating interface with low skin impedance. Its antioxidant, antibacterial and anti-inflammatory properties protect micro-interfaces and prolonged contact sites, improving comfort, tolerability and signal quality. Clinical-preclinical evidence on sericin gels, films and hydrogels shows acceleration of tissue repair and reduction of oxidative stress, essential qualities when electronics remain in contact with the epidermis for days or weeks.
The combination of fibroin substrates with sericin coatings and interfacial layers suggests immune-smart strategies to reduce inflammatory response and fibrosis around electrodes. The use of bioactive coatings based on silk proteins then favors tissue integration and long-term stability, a key requirement for soft recording/stimulation electrodes and for cutaneous-peripheral sensory bridges. Evidence on the benefits of biofunctionalized surfaces on flexible neural probes supports this design paradigm.
From epidermis to clinical cloud
Electronic skins based on fibroin, with conductive functional layers and sericin as skin interface, compose thin stacks that include multimodal sensors, haptic actuators, micro-energetics and radio modules. These layers can be printed and also transferred cold, maintaining their compliance and breathability. In clinical remote monitoring pathways, signal quality and skin stability are primary constraints, and it is here that the fibroin-sericin pair functions, specifically, as digital connective tissue that harmonizes mechanics, surface chemistry and bioelectronics, reducing artifacts and improving patient adherence.
The field is now moving towards skins that sense, communicate and self-power, and in perspective interact with the chemical environment. The arrival of optical/electronic e-skins and ambient energy membranes on protein matrix opens up prosthetics with realistic touch, safer collaborative robotics and neural interfaces pleasant to tissue. The specificity of fibroin as structural matrix and sericin as bioactive interface suggests resorbable or minimal-maintenance platforms, with sensors and actuators that dialogue with skin and peripheral nerves naturally.
