Biomedical Engineering Reference
In-Depth Information
d
n
4
y
3
n
g
|
1
Figure 12.1
Transfection efficiency of different nonviral vectors, including spermine-
pullulan, peptide TAT-modified PEI-b-cyclodextrin (Tat-cyd), PEI-
cyclodextrin (Cyd), and Lipofectamine 2000 (Lipofectamine 2k). For the
transfection assay, known amounts of MSCs were seeded into the 24-
well plate and cultured for 18 h before transfection. The vector/DNA
complex was prepared by mixing 1 mgofpGL3plasmidwith
appropriate amounts of vector. The vector/DNA complexes were added
to the 24-well plate and incubated for 6 h at 37 uC under 5% CO
2
atmosphere in serum-free DMEM. Then the DMEM was replaced with
fresh DMEM with 10% serum. After 96 h, a luciferase assay was carried
out according to the manufacture's instructions (Promega, USA). Light
units (LUs) due to luciferase activity were measured with chemilumin-
ometer (Autolumat LB953, EG&G Derthold, Germany). All the
experiments were carried out in triplicate to ascertain the reproducibility
of the results.
agents inside the cells or in the tissue will be more promising. Hence, a
targeting drug delivery system could be practically used to modify and regulate
the level and time period of gene expression.
32
In this case, MSCs could be
used for the targeted delivery of tumor therapeutic genes transfected by
nonviral vectors for their engraftment efficiency to tumor sites.
12.2.3 Three-Dimensional and Reverse Transfection Systems
Although a great improvement in the transfection efficiency has been made
using nonviral vectors, in most cases, nonviral systems could not reach the high
transfection efficiency and allow long-term transfection as viral vectors do. To
enhance the transfection efficiency, several other transfection approaches, such
as using a reverse transfection method and/or three dimensional (3D) systems,
were developed. By optimizing the transfection system, such as changing the
order of adding the gene complexes and cells, the cell culture environment can
be greatly improved, not only in the increased transfection efficiency of the
gene carrier, but also in a longer gene expression time.
31
The technology and methodology of gene transfection have become more
and more important to enhance the efficiency of gene therapy for several
diseases. The transfection system can greatly affect the growth status of cells
