Probiotic Bacteria as Therapeutics and Biohybrid Drug Carriers: Advances, Design Strategies, and Future Outlook

Probiotic bacteria have emerged as versatile and biocompatible platforms for drug delivery, offering a safe and efficient means of targeting diseased tissues. Advances in nanotechnology and genetic engineering have significantly expanded the potential of probiotic bacteria in precision medicine, enabling the delivery of therapeutics, proteins, antigens, and nanoparticles (NPs). This review explores diverse strategies for utilizing probiotics as drug carriers, including bacterial ghosts, outer membrane vesicles (OMVs), surface membrane proteins, and spores, focusing on applications in cancer therapy, vaccine development, and gastrointestinal disorders. We primarily focus on the strategy of integrating probiotics into nanoparticle-based delivery systems, examining key design considerations, such as functionalization strategies, targeting efficiency, and biocompatibility. Additionally, we highlight genetic engineering approaches, including plasmid-based expression and genomic integration, that enhance the probiotic functionality for targeted therapy, immunomodulation, and nanoparticle-mediated drug delivery. Further advancements in synthetic biology, biohybrid coatings, and stimulus-responsive mechanisms that could optimize the therapeutic efficacy of these systems will be discussed briefly. This review comprehensively analyzes recent progress and the outlook for harnessing probiotics for next-generation targeted drug delivery applications.