Experimental and clinical transplantation procedures involving hematopoietic stem cells (HSCs) are challenging because of the sparse population of stem cells in adult tissues. In addition, preclinical studies to understand basic stem cell transplantation biology such as clonal selection and the integrity and kinetics of stem cells cannot be conducted using current stem cell isolation or expansion technology.
For the past two decades investigators have undertaken HSC ex vivo expansion, which has led to multiple clinical studies. No significant clinical benefit has been reported, however. As a result, it is believed that stem cell expansion technology is not optimum enough to maintain progenitor cell populations without differentiation.
Increased knowledge of the hematopoietic stem cell niche, new methods to promote progenitor cell expansion without differentiation, and serum-free and animal protein free media for expanded adult HSCs may facilitate preclinical and clinical applications of stem cells.
Arteriocyte’s Nanex™ Stem Cell Ex vivo Expansion System is for adult HSCs. Nanex, which was originally developed by Hai-Quan Mao at Johns Hopkins University, is a biofunctional nanofiber-based scaffold that partially mimics the bone marrow stem cell niche to provide efficient expansion of human bone marrow, peripheral blood, or umbilical cord blood derived HSCs.
Nanex is prepared by electrospinning polyethersulfone fibers in nanoscale and then treating the surface with amine groups (Figure 1). The biofunctional surface together with its topographical structure facilitates the proliferation of HSCs while maintaining the stem cell phenotype in a 10-day serum-free and animal protein free culture (Figure 2).