cytoplasm, nuclear uptake and expression of the gene, in addition to the cell’s

metabolic activity, and reproduction state. The primary mechanism for biomolecules

releasing into the cells involves cell surface receptors that latch onto the cell-like

liposomal reagents, triggering receptor-complex interactions and internalization

through endocytosis. Most of the cells except a few are covered with these surface

receptors and have rapid division, high rate of endocytosis, and high metabolic

activity, thus making them a good model for transfection. On the other hand,

immature cells, including stem cells, and uncommitted progenitor cells are devoid

of these features. Similarly, primary cells often employed as in vitro models in basic

research and drug discovery have lower endocytosis uptake and less reproduction

activity and are unable to adhere to transfection complexes. In these models,

magnetofection is an effective approach to deliver biomolecules such as DNA,

RNA, and protein for in vitro and in vivo applications, enabling incorporation of

the transfection complexes without physically introducing pores on cell membrane

or causing damage in the cells. It uses metallic NPs coated with cationic molecules

complexed with biomolecules including naked, packed, or virus-enveloped portion,

which are bound by electrostatic and hydrophobic bonds. These magnetofectin

complexes attach loosely to the cells but, under the influence of a magnetic field

created by placing a magnet under the culture dish, are localized, concentrated onto

the cell surface, and eventually internalized through endocytosis (Figs. 17.2 and

17.3). In contrast to other mechanical techniques such as gene guns, electroporation,

and sonoporation, magnetofection does not compromise the cell membrane or cause

cell death; instead it imparts the lowest level of stress, along with maximum

efficiency of transgene expression.

Another advantage of magnetofection is consistency. Once the protocol for the

gene incorporation or protein yield is optimized, conditions are reproducible for

yielding identical results. Considering the numerous benefits, it is expected that

application of magnetofection will broaden in biomedical science in future. They

also have a remarkable potential in clinical setting or bedside use. These

magnetofectin complexes can be modified in vitro as CART (chimeric antigen

Fig. 17.2 Principle of

magnetofection. Magnetic

nanoparticles are coated with

different types of drugs and

delivered near the cells under

the influence of an external

magnet. Magnetic field directs

the drug-coated magnetic

nanoparticles toward the cell

and facilitates fast, effective,

and localized drug delivery in

in vitro models

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J. Singh et al.