BOC Sciences is a life science group with its headquarter in New York. We are dedicated to providing the most complete in vivo and in vitro nucleic acid and protein transfection solutions to support gene and cell therapy, biologics production, and life science research.

1. What is transfection?
Broadly speaking, transfection is the process of introducing nucleic acid (DNA or RNA)
into eukaryotic cells by non-viral methods. This introduction of foreign nucleic acids
using various chemical, biological, or physical methods can lead to changes in cell
properties, thereby allowing the study of gene function and protein expression in the
context of cells.
Transfection overcomes the inherent challenges of introducing negatively charged
molecules (for example, the phosphate backbone of DNA and RNA) into cells with
negatively charged membranes. In transfection, the introduced nucleic acid may
temporarily exist in the cell so that it can only be expressed for a limited time without
replication, or it can be stablilized and integrated into the genome of the recipient and
replicated in the host genome.
Transfection Terminology
Transfection Transformation Transduction
Definition
Transfection
commonly refers
to the
introduction of
nucleic acids
into eukaryotic
cells, or more
specifically,
into animal
cells. However,
its present
meaning includes
any artificial
introduction of
foreign nucleic
acid into a cell.
Transformation is
often used to
describe the
non-viral DNA
transfer in
bacteria,
non-animal
eukaryotic cells,
and plant cells.
Transduction is
used to describe
virus-mediated
DNA transfer.
Advantages and Disadvantages of the Different Transfection
Methods
Methods Advantages
Disadvanta
ges
Recommend
ed cells
BOC Sciences
Solutions

2. Chemical
Lipid
mediated
 High
efficiency-able to
effectively deliver
nucleic acids into
cells and obtain
measurable
changes
 Low
cytotoxicity
 Easy to
use-minimum
steps required;
adapt to high
throughput
systems
 Economi
cal-more active
lipids can reduce
costs and obtain
effective results
 Not
suitable for all
cell
types-some
cell lines
cannot be
transfected by
lipofection
Immortal
cells,
adherent
(attached
) or
suspended
cells
Most of our
products are
based on
cationic
lipid
Calcium
phosphate
 High-effi
ciency
 Cheap
 Can be
applied to
multiple cell
types
 Small
pH changes
(±0.1) may
affect the
efficiency
 The
size and
quality of the
sediment are
critical to
success
Adherent
and
nonadhere
nt cell
lines.
Calcium
Phosphate
Transfection
Reagent
Cationic
Polymers
(e.g., PEI)
 No viral
vector
 Chemi
cal toxicity to
some cell
types
Tumor
cell
lines
PEI
Transfection
Reagent
DEAE-Dextran
 Cheap
 Easy to
perform and
quick
 High
concentrations
of
DEAE-dextran

3.  Suitable
to a wide range
of cell types
may be toxic
to cells
 Differ
ent
transfection
efficiency in
different cell
types
 Can
only be used
for transient
transfection
 Poor
performance
in primary
cells (usually <
10%)
Magnet
mediated
 Fast
 Improve
transfection
efficiency
through targeted
transport,
especially for
small amounts of
nucleic acids
 Gentle
treatment of cells
 Relativ
ely new
method
 Need
adherent cells;
suspension
cells need to
be fixed or
centrifuged
Immortal
cells,
Adherent
mammalian
cell
lines and
primary
cells
Biological
Viral
mediated
 Very high
gene delivery
efficiency,
95-100%
 Easy to
use
 Effective
for dissociated
cells, slices,
and in vivo
 Most
viruses need
P2
containment
 Risk of
foreign gene
integration
into the host
genome
 Many
viruses are
lytic
Attached
adherent
cells,
stem
cells,
primary
cells
 Virus
DNA Transfection
Reagent
 Lentivira
l Transfection
Reagent
 Polybren
e-Based Virus
Delivery Reagent

4.  Requir
es packaging
cell line
Immunogenicit
y
 DNA
package size
limit
Physical
Electroporat
ion
 No need
for vector
 Easy and
rapid
 Not alter
target cell
morphology and
functions
 Dema
nds
experimenter
skill, laborious
procedure
 Need
to determine
the optimum
electroporatio
n conditions
 Can
cause cell
death if
transfection is
not performed
under
optimum
conditions
A variety
of cells
(especial
ly cells
that are
difficult
to
transfect
, such as
primary
and stem
cells)
Electroporat
ion Products
Factors affecting transfection efficiency
 Cell passage number
Keep the number of passages<50. In addition, the number of cell passages used in
various experiments should be consistent.
 Cell state
Cells should be grown in a medium suitable for the cell line and supplemented with
serum or growth factors according to survival needs. Contaminated cells and media
must not be used for transfection. If the cells are damaged in any way, they should be
discarded and re-seeded from frozen, uncontaminated stock.
 Cell density

5. Normally, the confluency of the transfected cells is 40-80%. Too few cells will cause
the culture to grow poorly without cell-to-cell contact. Too many cells can lead to
contact inhibition, which prevents the cells from absorbing foreign DNA.
 Nucleic Acid Quality and Quantity
The plasmid DNA used for transfection should be free of protein, RNA, chemical, and
microbial contamination, and the appropriate final concentration is 0.2-1mg/ml. The
optimal amount of DNA used for transfection depends on the type of DNA, transfection
reagent, target cell line, and the number of cells.
 Cytotoxicity of transfection reagent
When choosing a transfection method or reagent, both the transfection efficiency and
the level of cytotoxicity must be considered. Higher transfection efficiency contributes
to greater success. However, low toxicity methods cannot be ignored, because highly
cytotoxic methods can cause adverse effects in the form of visible morphological
changes and unknown changes in gene expression or stress response pathways.
Transfection classification and application
Transfection is used to study the function and regulation of genes or gene products, to
produce genetically modified organisms, and is used as a powerful analysis tool for
gene therapy methods. According to the time range of the desired experiment and the
goal, transfection can be divided into transient transfection and stable transfection.
 Transient transfection
Transiently transfected cells are usually harvested within 24-96 hours after
transfection. They are usually used to study the short-term expression of genes or
gene products, perform RNA interference (RNAi)-mediated gene silencing, or
rapidly-produce recombinant proteins.
 Stable transfection
In order to obtain long-term gene expression, the DNA vector needs to be integrated
into the host chromosome. This process requires selective screening and clonal
isolation. It is usually used for long-term pharmacological research, gene therapy, or
long-term genetic regulation mechanism research.