Stem Cell Imaging Using Nanoparticles
Xarrin Sindhu
The Next Big Small thing
Stem Cell Imaging Using Nanoparticles
Nanotechnology expansive pace of progress
Tracking distribution of stem cells crucial regarding their therapeutic use
distinguishing cellular origination from a cell source
development of noninvasive techniques to trace therapeutic stem cells
A non-invasive techniqueOne such method is the use of:
superparamagnetic nanoparticles coated with polymer shell
has been used to track transplanted
stem cells.
as contrast agents for magnetic resonance (MR)
imaging
Video Demonstration
Stem cell labelling techniques
Conventional techniques
• rely on the surface attachment of magnetic beads (with size from 100 nm to m)
Latest techniques
• Super para magnetic nano particles coated with a polymer shell magnetic resonance (MR) imaging
DrawbacksConventional methods are efficient for in vitro cell separation
1
cell surface unsuitable for in vivo use due to rapid recognition and clearance of labeled cells in the reticuloendothelial system
2
New technique
short HIV-Tat peptides are used to derive super paramagnetic nanoparticles up to 10–30 pg of superparamagnetic iron per cell.
Iron incorporation does not affect cell viability, differentiation, or proliferation of CD34þ cells.
particles are efficiently internalized into hematopoietic and neural progenitor cells
tissue homed to the bone marrow and single cells could be detected by magnetoresonance imaging in the tissue samples.
Video Demonstration
Mechanism
Magnetic separation columns recover magnetically labeled cells homed to the bone marrow
Inference
Localization and retrieval of cell populations in vivo enable the detailed analysis of specific stem cell and organ interactions critical for advancing the therapeutic use of stem cells
Additional studysuperparamagnetic iron oxide nanoparticles were
fabricated and optimized to exhibit superior magnetic properties
Human neural stem cells and MSCs were labeled in vitro by using these novel particles
found to retain proliferation and differentiation
capabilities
analyzed in vitro and
Image displays the 1000s of iron oxide nanoparticles (yellow) inside a single stem cell, which ‘light up’ on MRI scans.
This technique has the potential to monitor stem cells' integration into human tumours.
So…• Super paramagnetic
iron oxide nanoparticles were fabricated and optimized to exhibit superior magnetic properties.
• Human neural stem cells and MSCs were labeled in vitro by using these novel particles, analyzed in vitro, and found to retain proliferation and differentiation capabilities
ExampleRat neural stem cells were differentiated into oligodendroglial progenitors
both lateral ventricles of myelin basic protein–deficient neonatal rats.
injected into
and
Cont’d
The cells were found in vivo by using an animal MR imaging unit for 6 weeks post transplantation.
The labeled cells were able to induce new myelin formation;
Thus, labeling by nano particles does not alter the differentiation and therapeutic potentials of stem cells
What else nano imaging offers ?
Another field of stem-cell research in which nanoparticles are used to track cells by in vivo imaging has great importance in MSC-based myocardium dysfunction therapy.
Labeled porcine MSCs retained in vitro viability and proliferation and differentiation capabilities, as well as in vivo viability after allogeneic transplantation.
Result of MSC based therapy
The labeled MSCs demonstrated useful contrast characteristics; one could distinguish labeled MSCs from unlabeled MSCs in vitro and in fresh myocardial tissue
The contrast proved satisfactory within normal or infarcted myocardium, both of which may be targeted in future MSC therapiesA minimal detectable quantity of cells (105 cells=injection) was located using conventional cardiac MR imaging, which was performed on a commercial imaging unit.
Cont’d
In this preliminary experience, the authors observed iron fluorophore particles (IFP)–containing cells with a preserved nuclear structure that had elongated and aligned with host myocardial fibers. Whether the labeled MSCs indeed migrate, differentiate, and improve myocardial function after transplantation remains to be demonstrated in longer-term studies in which careful control groups are used
Discussion
Stem cell benefitsencouraged intense interest in using these for different
therapeutic applications
But still
several problems must still be resolved before stem-cell technology can advance to the clinical
setting
HurdlesTo date, no scaffold material has been deemed optimal for
specific use in tissue engineering
stem cells on scaffolds composed of degradable fibers with nanometric diameters––fibers that resemble the collagen
fibers inhabiting the ECM
One suggestion
Copy nature’s method
Discussion
Once we have answered the questions of which scaffold and delivery vector are optimal, we will be able to:
create new tissue
However, this leads us to another question: will this newly formed tissue function in the same manner as the tissue it is supposed to replace?
To answer this, we must perform a variety of tests, including biochemical, electrophysiological, and biomechanical analyses.
Cont’d
In some research models, the newly formed tissue is too small to be examined using conventional analytical methods
Cont’d
In the analysis of new bone tissue derived from genetically engineered MSCs
nanobiomechanical analyses of other skeletal tissues as well as individual cells and ECM molecules.
Such methods can be applied
to
Prenominal
Understanding the intrinsic biomechanical parameters of engineered tissue can lead to :
optimization of the engineering process and
The production of functional tissue replacements for the skeleton.
Considerations before implants
Finally, the question of bio distribution constantly arises within the context of cell therapy.
The adverse effect of implanted cells that have found their way to distant organs rather than to the target organ should be considered in every therapeutic protocol.
What else can be done with nanoparticles?
Specific nano particles have been developed for noninvasive monitoring of cell distribution within the body.
These particles can also be used to monitor stem-cell survival post implantation
and to inform us of whether these cells are only required as inducers of tissue regeneration
or play a long-term role in the generation of new tissue.
Conclusion
Conclusion
Nanotechnologies are beginning to be implemented as analytical and production tools in stem cell–based therapeutic approaches.
Only a few tools available in the field of nanoscience have been made available to advance the use of stem cells in medicine
L'avenir
The gap between scientists traditionally involved in nanoscience and scientists dealing with biotechnology will be bridged during the coming years, leading to an increased use of nanotools in biomedicine.
The future looks bright…
We envision the application of nanotechnology in studies of:
cell–scaffold
interactions
cell–matri
x interactions
cell preservation monito
ring
Totally radical future
No doubt, this will drive stem-cell therapy closer to clinical application in human beings.