BUFFALO, N.Y. -- A gene therapy method that doesn't rely on
potentially toxic viruses as vectors may be growing closer as the
result of in vitro research results reported by University
at Buffalo scientists in the current online issue of the
Proceedings of the National Academy of Sciences.
The paper, which describes the successful uptake of a
fluorescent gene by cells using novel nanoparticles developed as
DNA carriers at UB, demonstrates that the nanoparticles ultimately
may prove an efficient and desirable alternative vector to
Using confocal microscopy and fluorescent spectroscopy, the UB
scientists tracked optically in real-time the process known as
transfection, including the delivery of genes into cells, the
uptake of genes by the nucleus and their expression.
"We have shown that using photonics, the gene-therapy transfer
can be monitored, tracking how the nanoparticle penetrates the cell
and releases its DNA in the nucleus," explained Paras N. Prasad,
Ph.D., executive director of the UB Institute for Lasers, Photonics
and Biophotonics, SUNY Distinguished Professor in the Department of
Chemistry in the University at Buffalo's College of Arts and
Sciences, and a co-author of the paper.
"When the fluorescent protein was produced in the cell, we knew
transfection had occurred," he said.
The work is important in light of the difficulties that have
plagued gene-therapy human trials in recent years, including some
fatalities that may have resulted from the use of viral
"Efficient delivery of the desired gene and substantial release
inside the cell is the major hurdle in gene therapy," explained
Dhruba J. Bharali, Ph.D., a co-author and postdoctoral researcher
in the UB Department of Chemistry and UB's Institute for Lasers,
Photonics and Biophotonics, where the work was done.
"Viruses have been used as efficient delivery vectors due to
their ability to penetrate cells, but there is the chance they can
revert back to 'wild' type," he said.
While non-viral vectors are safer, he noted that it is much more
difficult to get them into cells and then to achieve the release of
DNA once they do penetrate cells.
The advantage of the UB team's approach, he explained, is that
unlike most other nonviral vectors, the DNA-nanoparticle complex
releases its DNA before it can be destroyed by the cell's defense
system, boosting transfection significantly.
The UB scientists also were able to use photonic methods to
provide an unprecedented look at how transfection occurs, from the
efficient uptake of nanoparticles in the cytoplasm to their
delivery of DNA to the nucleus.
"No gene-delivery vehicle -- either viral or non-viral -- has
ever been tracked in the cell before," explained Tymish Y.
Ohulchanskyy, Ph.D., the third co-author and post-doctoral research
scholar at the institute. "By using our photonics approach, we can
track gene delivery step by step to optimize efficiency," he
The research team makes its nanoparticles from a new class of
materials: hybrid, organically modified silicas (ORMOSIL).
"The structure and composition of these hybrid ORMOSILs yield
the flexibility to build an extensive library of tailored
nanoparticles for efficiently targeting gene therapy into different
tissues and cell types," said Prasad.
The UB researchers now are collaborating on in vivo
studies with colleagues from the UB School of Medicine and
Biomedical Sciences to use their novel nanoparticles to transfect
neuronal cells in the brains of mice.
This research was supported by the U.S. Air Force through its
Defense University Research Initiative on Nanotechnology (DURINT)