Gene Delivery Using Physical Methods - Challenges in Delivery of Therapeutic Genomics and Proteomics - page 110

The impalefection technique has been used for successful in vitro gene transfec-
tion. The study carried out by Peckys et al. in Chinese hamster lung epithelial cells
(V79) revealed successful delivery of dsDNA using the impalefection method, with
better expression in the target cells [278] . The delivery of tetracycline-inducible small
hairpin RNA (shRNA) vector system designed for silencing cyan fluorescent protein
(CFP) expression alongside the yfp marker gene in Chinese hamster ovary cells using
impalefection on VACNFs resulted in efficient CFP silencing in a single cell among a
population of cells that bear CFP-expressing potential [279] . The project carried out
at �und University, Sweden, demonstrated efficient parallel impalefection of nerve
cells, using surface-coated nanowires [275] . VACNF arrays provided a mechanism
for extremely rapid expression, silencing, and tracking in target cells. Further explo-
ration of this method will aid in better application of this method in clinical practice.
There are various physical nonviral methods utilizing the application of external
physical forces for enhanced transgene delivery. The principle, advantages, and limi-
tations of each method for gene delivery have been summarized in Table 3.3 .
3.12 Conclusion
Tremendous advances have taken place in nonviral gene delivery systems in recent
decades. It is important to note that therapeutic applications of these nonviral gene
delivery systems are rather limited despite the progress in vector design and the
understanding of transfection biology. Thus, improved and continuous efforts are
required to enhance the transfection efficiency of currently available methods without
compromising method safety. The applications and success of various physical meth-
ods depend on identifying the critical parameters limiting gene delivery in current
systems and overcoming them in vivo for therapeutically effective gene delivery. The
differences in extracellular and intracellular structures in various tissues and organs
also determine which methods are safest and most effective. A thorough understand-
ing of the differences among various organs, tissues, and types of cells and cell biol-
ogy in response to physical impacts can trigger the development of effective devices
and procedures applicable to humans. However, further studies are needed to explore
their possible use in vivo and in clinical practice.
Future research in the field will focus on biological and cellular responses to the
process of physical stimulation involving gene transfer. Innovations in applying the
principles of physics, chemistry, and biology to the development of safe and effective
methods for gene delivery are the key to making the urgently needed breakthroughs
in nonviral gene therapy.
Acknowledgment
The authors acknowledge the financial assistance from the Council of Scientific
and Industrial Research (CSIR), New Delhi, India, and TIFAC CORE in NDDS,
Government of India, New Delhi, for providing research facilities to the team.