Peripheral nerve injury often results in poor recovery of function and subsequent impaired quality of life for the patient.A severe nerve injury leads to critical-sized nerve gaps and requires surgical repair with autologous or engineered nerve grafts.Though many approaches to enhance peripheral nerve regeneration have not outperformed thegold standardset by au-tograft procedures,studies over the past few decades have resulted in several novel engineered conduits to improve nerve regeneration and to develop new strategies including peripheral nerve interfaces to improve upper limb control.To address two main limitations,i.e.,the lack of satisfying control strategies and poor sensory feedback,we developed longitudinal in-trafascicular electrodes and biodegradable regenerative type neural interfaces to provide more natural control and deliver both motor commands and sensory feedback in the peripheral nervous system.Recently we developed a novel 3D printing methodology for a custom nerve repair technology for the regeneration of complex peripheral nerve injuries containing bi-furcating sensory and motor nerve pathways,with biomimetic physical cues (microgrooves) and path-specific biochemical cues (spatially controlled multicomponent gradients).The in vivo studies examining the regeneration effect of bifurcated in-juries across a 10 mm complex nerve gap in rats showed that the 3D printed scaffolds resulted in enhanced functional return of the regenerated nerve and demonstrated the advantage of 3D printing toward advancing tissue regeneration after complex nerve injury.