Production of antisera in rabbits using calcium alginate as an antigen depot

Alginate microfibers as therapeutic delivery scaffolds and tissue mimics

Alginate, a naturally occurring polysaccharide, has been widely used in cell encapsulation, 3D culture, cell therapy, tissue engineering, and regenerative medicine. Alginate's frequent use comes from its biocompatibility and ability to easily form hydrogel in a variety of forms (e.g. microcapsules, microfibers, and porous scaffolds), which can provide immunoprotection for cell therapy and mimic the extracellular matrix for tissue engineering. During the past 15 years, alginate hydrogel microfibers have attracted more and more attention due to its continuous thin tubular structures (diameter or shell thickness ⩽ 200 µm), high-density cell growth, high handleability and retrievability, and scalability. This review article provides a concise overview of alginate and its resultant hydrogel microfibers for the purpose of promoting multidisciplinary, collaborative, and convergent research in the field. It starts with a historical review of alginate as biomaterials and provides basics about alginate structure, properties, and mechanisms of hydrogel formation, followed by current challenges in effective cell delivery and functional tissue engineering. In particular, this work discusses how alginate microfiber technology could provide solutions to unmet needs with a focus on the current state of the art of alginate microfiber technology and its applications in 3D cell culture, cell delivery, and tissue engineering. At last, we discuss future directions in the perspective of alginate-based advanced technology development in biology and medicine.

CELL WALL REPLICATION. I. CELL WALL GROWTH OF BACILLUS CEREUS AND BACILLUS MEGATERIUM

Cell wall replication of Bacillus cereus and Bacillus megaterium was studied by differential labelling with fluorescent and non-fluorescent antibody.Growth of new cell wall in B. cereus was initiated near the poles. In the old wall, additional new wall segments gradually developed to form an alternating pattern of new and old wall segments. Further growth elongated the new wall and pushed the old segments apart. Separation of daughter cells appeared to involve splitting of the transverse septa laid down at or near the old wall segments.Growth of new cell wall of B. megaterium was initiated either at one of the poles or at the central area of the cell. Multiple segments of new and old wall appeared along the cell length. Further elongation was followed by formation of transverse septa and separation of daughter cells incorporating either old or new wall segments.Our evidence clearly shows that growth and elongation of the two bacilli do not occur by diffuse intercalation of new cell wall into the old.