Biomedical Engineering Reference
In-Depth Information
Chapter 9
Nanoparticles for Stem-Cell Engineering
Esmaiel Jabbari
Biomimetic Materials and Tissue Engineering Laboratories, Department of Chemical Engineering,
University of South Carolina, Columbia, SC, USA
Introduction
Currently, there are 120,000 patients in the United States alone on the waiting list for an
organ transplant, and 5000 new patients are added to the list each year [1]. In 2012, 28,000
organ transplants were performed with 14,000 donated organs and 46,000 corneal trans-
plantations were performed to restore vision, while 65,000 patients died from the lack of an
available organ for transplantation in the same year [1]. A viable approach to reduce the
waiting time for transplant patients or eliminate the shortage of organs is to use tissue-
engineering strategies to regenerate lost or injured tissues [2, 3]. Tissue engineering (TE) is
based on the belief that the cell is the basic building block of tissue, and tissues and organs
can be regenerated by placing cells in a supporting matrix loaded with growth factors to
guide their maturation to the desired lineage [4, 5]. In that regard, attempts have been made
to regenerate a variety of tissues, including musculoskeletal [6-11], cardiovascular [12-15],
neural tissues [16-19] and other living tissues [20-22], using a combination of scaffold, stem
cells, and growth factors. The first TE bladder transplant was successfully performed in 2006
in the United States [23, 24], followed by the successful transplantation of a TE trachea
using the patient's own stem cells in 2008 in Spain [25, 26].
One of the major challenges in the development of TE implants is the selection of a reli-
able cell source and methods to control the cell fate in the implanted matrix. The identification
of pluripotent stem cells in the embryo [27-31], fetus [32], umbilical cord [33], and amniotic
fluid [34], the isolation of multipotent adult stem cells in many tissues and organs [35], like
the bone marrow cavity [36-38], and the induced pluripotent cells derived from the patient's
skin [39-41], have resulted a wide range of options for cell selection in regenerative medicine.
However, the safe use of pluripotent stem cells in regenerative medicine requires tight con-
trol over their differentiation and lineage commitment and their confinement to the site of
regeneration [42, 43]. Growth factors that control the fate of progenitor cells are balanced in
the natural tissue by enzymatic clearance [44-46], restricted expression [47-49], pro-protein
domains [50, 51], binding proteins [52-54], and other soluble factors [51, 55]. Therefore,
delivery systems that temporally and spatially regulate the distribution and availability of
