Engineered Microorganisms for Advancing Tumor Therapy.

Engineered microorganisms have attracted significant interest as a unique therapeutic platform in tumor treatment. Compared with conventional cancer treatment strategies, engineering microorganism-based systems provide various distinct advantages, such as the intrinsic capability in targeting tumors, their inherent immunogenicity, in situ production of antitumor agents, and multiple synergistic functions to fight against tumors. Herein, the design, preparation, and application of the engineered microorganisms for advanced tumor therapy are thoroughly reviewed. This review presents a comprehensive survey of innovative tumor therapeutic strategies based on a series of representative engineered microorganisms, including bacteria, viruses, microalgae, and fungi. Specifically, it offers extensive analyses of the design principles, engineering strategies, and tumor therapeutic mechanisms, as well as the advantages and limitations of different engineered microorganism-based systems. Finally, the current challenges and future research prospects in this field, which can inspire new ideas for the design of creative tumor therapy paradigms utilizing engineered microorganisms and facilitate their clinical applications, are discussed.

Microalgae-loaded biocompatible alginate microspheres for tissue repair.

Hydrogel-based microcarriers have demonstrated effectiveness in wound repair treatments. The current research focus is creating and optimizing active microcarriers containing natural ingredients capable of conforming to diverse wound shapes and depths. Here, microalgae (MA)-loaded living alginate hydrogel microspheres were successfully fabricated via microfluidic electrospray technology, to enhance the effectiveness of wound healing. The stable living alginate hydrogel microspheres loaded with photoautotrophic MA were formed by cross-linking alginate with calcium ions. The combination of MA-loaded living alginate microspheres ensures high biocompatibility and efficient oxygen release, providing strong support for wound healing. Concurrently, vascular endothelial growth factor (VEGF) has been successfully introduced into the microspheres, further enhancing the comprehensive effectiveness of wound treatment. Covering the rat's wound with these MA-VEGF-loaded alginate microspheres further substantiated their significant role in promoting collagen deposition and vascular generation during the wound closure processes. These results confirm the outstanding value of microalgae-loaded live alginate hydrogel microspheres in wound healing, paving the way for new prospects in future clinical treatment methods.

Living Chinese Herbal Scaffolds from Microfluidic Bioprinting for Wound Healing.

Biological scaffolds have been widely employed in wound healing applications, while their practical efficiency is compromised by insufficient oxygen delivery to the 3-dimensional constructs and inadequate nutrient supply for the long-term healing process. Here, we present an innovative living Chinese herbal scaffold to provide a sustainable oxygen and nutrient supply for promoting wound healing. Through a facile microfluidic bioprinting strategy, a traditional Chinese herbal medicine (Panax notoginseng saponins [PNS]) and a living autotrophic microorganism (microalgae Chlorella pyrenoidosa [MA]) were successfully encapsulated into the scaffolds. The encapsulated PNS could be gradually released from the scaffolds, which promoted cell adhesion, proliferation, migration, and tube formation in vitro. In addition, benefiting from the photosynthetic oxygenation of the alive MA, the obtained scaffolds would produce sustainable oxygen under light illumination, exerting a protective effect against hypoxia-induced cell death. Based on these features, we have demonstrated through in vivo experiments that these living Chinese herbal scaffolds could efficiently alleviate local hypoxia, enhance angiogenesis, and thereby accelerate wound closure in diabetic mice, indicating their great potential in wound healing and other tissue repair applications.

Freezing biological organisms for biomedical applications.

Biological organisms play important roles in human health, either in a commensal or pathogenic manner. Harnessing inactivated organisms or living organisms is a promising way to treat diseases. As two types of freezing, cryoablation makes it simple to inactivate organisms that must be in a non-pathogenic state when needed, while cryopreservation is a facile way to address the problem of long-term storage challenged by living organism-based therapy. In this review, we present the latest studies of freezing biological organisms for biomedical applications. To begin with, the freezing strategies of cryoablation and cryopreservation, as well as their corresponding technical essentials, are illustrated. Besides, biomedical applications of freezing biological organisms are presented, including transplantation, tissue regeneration, anti-infection therapy, and anti-tumor therapy. The challenges and prospects of freezing living organisms for biomedical applications are well discussed. We believe that the freezing method will provide a potential direction for the standardization and commercialization of inactivated or living organism-based therapeutic systems, and promote the clinical application of organism-based therapy.