Encapsulation materials and oral delivery of probiotics: mechanisms, evaluation metrics, and translational perspectives

Oral delivery technology is central to enabling the therapeutic and health-modulating functions of probiotics within the intestine, which directly determine the efficacy of probiotics against conditions. However, probiotics face multiple physiological barriers during the oral delivery process which reduce their viability, impair targeting, and severely limit clinical translation. Consequently, the development of efficient and stable encapsulation systems has become a crucial step in advancing probiotic therapeutics. This article aims to systematically review the mainstream material systems used for the encapsulation and delivery of probiotics and their latest research advances. It focuses on five major types of carriers-polysaccharides, proteins, mineralized materials, metal-phenolic networks, and cell membrane-mimicking materials-discussing their encapsulation mechanisms, functional characteristics, and application advantages. By comparatively analyzing the performance of these materials in enhancing the gastrointestinal survival rate, achieving targeted release, and improving storage stability of probiotics, this review not only summarizes the technical features and limitations of existing encapsulation strategies but also looks forward to the future trend of probiotic delivery systems toward integration, intelligence, and functionalization. This review provides theoretical insights and technical pathways for the design and optimization of probiotic formulations, promoting their broader application in the health industry. Compared with previous reviews that mainly introduce single material categories or individual encapsulation technologies, this review uses a unified comparison framework based on material construction, strain compatibility, protection/release performance, safety, and food/health application potential. The analysis suggests that practical formulation design should match carrier chemistry with strain physiology and processing conditions rather than treating probiotics as a uniform entity.