M Mollapour Sisakht - Department of Biochemis try, Erasmus University Medical Center,Rotterdam, The Netherlands . Department of S tem Cell and Regenerative Medicine Center ofExcellence, Tehran University of Medical Sciences, Tehran, Iran

Organoid as an aggregation of adult s tem cell, progenitor of cellsand induced pluripotent s tem cell can recapitulate organ functionin miniature. This technology become interes t during las tdecade and have been developed for different organs. Organoidare very promising for personalize and regenerative medicines.However, organoids are currently cultured in matrigel which isprepared from the secretion of Engelbreth-Holm-Swarm mousesarcoma cells. Matrigel is complex, expensive and also poorlydefined, with high batch to batch variation. Besides, the xenogeneicorigin confide the clinical application. Here, we describeusing a combination of alginate. Alginate is a natural polymerproduced by brown algae commonly used in biomedical applicationsbecause of its biocompatibility, low cos t, and low cytotoxicity.To the bes t of our knowledge, this is the firs t reportof culturing, optimizing and characterization bladder organoidand tumoroids in this scaffold. For this purpose, we culturedthe patient-derived tissue samples, and assessed them for theability of grow, sub culturing capability, long term proliferation potential, size, viability and also expression of specific bladderorganoid markers contain CK۱۴, CK۲۰, LGR۵, UroplakinIII, FOX۱A,GATA۳,CK۵ and CK۴۴ by RT-PCR. The organoidforming efficiency was evaluated by imaging through confocalmicroscopy for specific bladder organoid markers (CK۲۰ andUroplakin III) and proliferation marker such as KI۶۷ as well.The results indicate that alginate is very promising for humanbladder organoid culture and has the potential to be used in avariety of clinical applications as well as culturing other typesof organoids, especially for the low resources situation

Alginate, Bladder, Organoid, Tumoroids