Pradeep Kumar | Rungta Engineering College, Raipur (original) (raw)

Papers by Pradeep Kumar

Synthetic chemical vectors have recently provided a versatile and robust platform for the safe an... more Synthetic chemical vectors have recently provided a versatile and robust platform for the safe and
efficient delivery of exogenous genes. Here, for the first time, a small series of Nbutyltriphenylphosphonium
bromide-grafted-linear polyethylenimine (BTP-g-lP) polymers (N–P
hybrid polymers) have been evaluated for their ability to deliver genes into mammalian cell lines, viz.,
MCF-7 and A549 cells. Biophysical characterization revealed that the projected polymers efficiently
interacted with plasmid DNA, and the resulting complexes displayed hydrodynamic diameters in the
range of 249–307 nm with relatively higher zeta potential values of +31 to +34 mV (cf. lPEI, +26 mV).
The tethering of lipophilic and cationic triphenylphosphonium moieties to linear PEI (lPEI) addressed
several limitations associated with lPEI, such as solubility, the stability of the pDNA complexes and the
timely release of pDNA for nuclear localization as assessed by protection and release assays. Also, the
lipophilic interactions between cellular membranes and the pDNA complexes mediated the efficient
cellular uptake and internalization of the pDNA complexes, resulting in significantly higher
transfection efficiency in these cell lines, outperforming the GenePORTER 2, Lipofectamine and
Superfect used in the study for comparison purposes. Confocal studies using dual-labeled TMRBTP-
g-lP3/YOYO-1-pDNA complex in MCF-7 cells confirmed that the complex behaved more or less
like native lPEI, as the substitution of the phosphonium moiety was too small to affect the intracellular
trafficking. Furthermore, the versatility of the BTP-g-lP3 vector was established by GFP specific
siRNA delivery, which resulted in 79% suppression of targeted gene expression (cf. Lipofectamine,
55%). Altogether, the study demonstrates the potential of these hybrid polymers for the efficient
delivery of nucleic acids for future gene therapy applications.

Recently, non-viral vectors for nucleic acid delivery have received considerable attention. Among... more Recently, non-viral vectors for nucleic acid delivery have received considerable attention. Among the
various non-viral vectors, branched polyethylenimine (bPEI, 25 kDa) has been one of the most widely
used carrier systems due to its high transfection efficiency, however, it imparts high cytotoxicity. In this
study, we have crosslinked bPEI with a bioreducible linker, 3,3’-dithiodipropionic acid (DTPA), via electrostatic
interactions to obtain DTPA crosslinked bPEI (DP) nanoparticles. The crosslinking significantly
reduced the cytotoxicity of the nanoparticles. To arrive at the best formulation in terms of nucleic acid
transfection, a series of DP nanoparticles were prepared by varying the percentage of crosslinking. The
dual action of DTPA, i.e. partial blocking of the charge density as well as crosslinking to convert bPEI into
its nanoparticles, did not alter the pDNA condensation ability of the so-formed nanoparticles, rather the
strategy favoured the unpackaging of the complexes inside the cells improving the release of pDNA,
which resulted in a higher transfection efficiency. All the formulations carried nucleic acids inside the cells
and exhibited significantly higher transfection efficiencies than native bPEI and the commercial transfection
reagent, Lipofectamine™. Sequential siRNA delivery displayed significant suppression in the target
gene expression. All together, the evaluation of the delivery systems demonstrates that the newly
synthesized DP NPs are quite promising as non-viral gene carriers.

In recent years, dendrimers have emerged as the most widely explored materials for theranostics e... more In recent years, dendrimers have emerged as the most widely explored materials for theranostics emphasizing
their potential in therapeutic delivery and diagnostics as well as in pharmaceutical technology.
Amongst them, PAMAM dendrimers have been extensively studied for their prospects in various biomedical
applications due to their defined structures and distinctive features such as monodispersity, uniformity
and amenability to functionalization. Here, low generation PAMAM dendrimers (G2–G4) have
been modified via Michael addition reaction followed by amidation with an oligoamine linker, tetraethylenepentamine
(TEPA). Subsequently, these modified dendrimers were characterized by physicochemical
techniques and evaluated for their capability to transfer nucleic acids in vitro. The results displayed significant
improvements in the transfection efficiency in both HeLa and A549 cells maintaining higher cell viability.
Sequential delivery of GFP-specific siRNA resulted in ∼73% suppression of the target gene. Flow
cytometry results revealed that one of the formulations, mG3–pDNA complex, exhibited the highest gene
transfection (∼49–68%) outperforming pDNA complexes of native dendrimers and the standard transfection
reagent, Superfect (∼32–36%). All these results ensure the potential of the modified dendrimers as
effective vectors for future gene delivery applications.