Robots and robotic prostheses have a limited grasp on the delicacies of gripping and manipulating objects. Applying the correct amount of force can be a difficult task when robot fingers cannot really feel objects contacted. A highly sensitive, 3D-printed fingertip has been engineered at the University of Bristol, U.K., to improve the performance of prosthetic hands by imparting a sense of touch.

The fingertip device incorporates a 3D-printed mesh of pin-like papillae on the underside of the compliant skin, which mimic the dermal papillae found between the outer epidermal and inner dermal layers of human tactile skin. The papillae are fabricated on advanced 3D-printers that can combine soft and hardPins on the inside of the skin replicate dermal papillae that are formed inside human skin. Source: University of Bristol materials to replicate complicated biological structures. Composed of rubber-like material and soft elastomeric gel, the fingertip could potentially allow amputees to feel objects through prosthetic limbs.

Natural touch experiments compared artificial neural recordings obtained from the fingertip with real neural data to assess how close the artificial fingertip comes to the real thing. The researchers observed that the 3D-printed tactile fingertip described in the Journal of The Royal Society Interface can produce artificial nerve signals that look like recordings from real, tactile neurons.

Despite the close match between the artificial fingertip and human nerve signals, the device was not as sensitive to fine detail. This is attributed to the thicker nature of the 3D-printed relative to real skin, and the researchers will next explore 3D printing of structures on the microscopic scale of human skin.