Adeno‐Associated Virus‐Encapsulated Alginate Microspheres Loaded in Collagen Gel Carriers for Localized Gene Transfer

Abstract This work reports localized in vivo gene transfer by biodegradation of the adeno‐associated virus‐encapsulating alginate microspheres (AAV‐AMs) loaded in collagen gel carriers. AAV‐AMs are centrifugally synthesized by ejecting a mixed pre‐gel solution of alginate and AAV to CaCl 2 solution to form an ionically cross‐linked hydrogel microsphere immediately. The AAV‐AMs are able to preserve the AAV without diffusing out even after spreading them on the cells, and the AAV is released and transfected by the degradation of the alginate microsphere. In addition, AAV‐AMs can be stored by cryopreservation until use. By implanting this highly convenient AAV‐encapsulated hydrogel, AAV‐AMs can be loaded into collagen gel carriers to fix the position of the implanted AAV‐AMs and achieve localized gene transfer in vivo. In vivo experiments show that the AAV‐AMs loaded in collagen gel carriers are demonstrated to release the encapsulated AAV for gene transfer in the buttocks muscles of mice. While conventional injections caused gene transfer to the entire surrounding tissue, the biodegradation of AAV‐AMs shows that gene transfer is achieved locally to the muscles. This means that the proposed AAV‐loaded system is shown to be a superior method for selective gene transfer.