Bone repair and regeneration require physiological cues, including mechanical, electrical, and biochemical activity. Many biomaterials have been investigated as bioactive scaffolds with excellent electrical properties. Amongst biomaterials, piezoelectric materials (PMs) are gaining attention in biomedicine, power harvesting, biomedical devices, and structural health monitoring. PMs have unique properties, such as the ability to affect physiological movements and deliver electrical stimuli to damaged bone or cells without an external power source. The crucial bone property is its piezoelectricity. Bones can generate electrical charges and potential in response to mechanical stimuli, as they influence bone growth and regeneration. Piezoelectric materials respond to human microenvironment stimuli and are an important factor in bone regeneration and repair. This manuscript is an overview of the fundamentals of the materials generating the piezoelectric effect and their influence on bone repair and regeneration. This paper focuses on the state of the art of piezoelectric materials, such as polymers, ceramics, and composites, and their application in bone tissue engineering. We present important information from the point of view of bone tissue engineering. We highlight promising upcoming approaches and new generations of piezoelectric materials.

Mucosa can be found in the eyes, oral cavity, bladder, vagina, airways, and gastrointestinal tract. It is an attractive route of administration for systemic or topical delivery of therapeutics. However, the mucus layer acts as a protective barrier, limiting the amount of biomolecules that reach the underlying epithelium. Mucoadhesion, mucodiffusion, and mucolysis are well-established mucointeractive strategies that can improve therapeutic outcomes, but due to their individual limitations, the resulting delivery is often still unsatisfactory. In recent years, drug delivery systems have emerged that combine multiple mucointeractive strategies, which we define here as hybrid mucointeractive delivery systems. This work aims to provide a general overview of such drug delivery systems, which include particle-releasing macrostructures such as gels, foams, films, and fibers, as well as systems such as zeta potential-changing particles and self-emulsifying drug delivery systems. Their potential, possible future, and limitations are discussed as well.