Near-IR absorbing quantum dots might be usable for growth factor-based differentiation of stem cells

Abstract

For stem cell therapy of degenerative diseases, it is necessary to differentiate stem cells into the specific lineage. There are several growth factors which have been used for differentiation of stem cells. Some growth factors can dose-dependently induce differentiation of stem cells so that the increase of growth factor concentration results in production of the higher level of differentiated cells. However, due to the toxicity of some differentiation factors (e.g. retinoic acid), the lower dose of growth factors for the specific lineage differentiation of stem cells is desirable. This paper suggests a new approach in the field of controlled growth factor delivery system using semiconductor nanocrystals; known as quantum dots (QDs). This system contains polymeric microencapsulated growth factor which is conjugated to near infrared (NIR) absorbing QDs. The control release of growth factors from microcapsules in the culture plates can be achieved by irradiation. To modulate growth factor release in response to stem cells needs for differentiation, the intensity and period of irradiation will be controlled. Our hypothesis is based on the fact that QDs can absorb NIR energy and by excitation of electrons and then vibrational relaxation of them become heated when they were irradiated and then release growth factors. We believe that controlled growth factors delivery through the suggested system is an effective method to reduce the amount of growth factors required for differentiation of stem cells.

The Combined Thermoresponsive Cell-Imprinted Substrate, Induced Differentiation, and "KLC Sheet" Formation

“…Like specific substrates and scaffolds, growth factors possess a significant role in stem cell differentiation. 11 It has been shown that the combination of both scaffold and growth factors can facilitate the orientation of stem cells toward target lineages. Particular physicochemical properties of ECM dictate specific cell responses by engaging relevant signaling pathways.…”

A Substrate for Stem Cell Culture and Differentiation

“…But, Brownian motion of growth factors in the medium leads only a small amount of them to reach biological signal pathway cell receptors. Hence, even if a large amount of growth factors is added to culture medium, only a small portion is involved in the differentiation of stem cells (9). Moreover, stem cells can be stimulated by chemical or topographical cues (10).…”