posted on 2018-06-29, 00:00authored byTiantian Wu, Zhiliang Li, Yajie Zhang, Jinkai Ji, Yun Huang, Hao Yuan, Fude Feng, Kirk S. Schanze
Conjugated polymers
can serve as good photosensitizers in biomedical applications. However,
it remains unknown whether they are phototoxic to the supercoiled
structure of DNA in improving gene delivery by the photochemical internalization
(PCI) strategy, which complicates the application of conjugated polymers
in gene delivery. In this work, we introduced a trace amount of cationic
poly(phenylene ethynylene)s (cPPEs) into the polymeric shell of branched
polyethylenimine (BPEI)/DNA complexes, studied the photosensitization
of singlet oxygen by cPPEs, and confirmed that the supercoiled DNA
is undamaged by the singlet oxygen generated by the photoexcitation
of cPPEs. By taking advantage of the cPPE-mediated PCI effect, we
report that the addition of the trace amount of cPPEs to the outer
shell of the BPEI/DNA polyplexes could greatly amplify the transfection
of gene green fluorescent protein on tumor cells with the efficiency
from 14 to 86% without decreasing the cell viabilities, well solving
the problem with a poor transfection capability of BPEI under low
DNA-loading conditions. Our strategy to employ conjugated polymers
as photosensitizing agents in gene delivery systems is simple, safe,
efficient, and promising for broad applications in gene delivery areas.