Sivanand S Pennadam

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Polymers that can respond to external stimuli are of great interest in medicine, especially as controlled drug release vehicles. In this critical review, we consider the types of stimulus response used in therapeutic applications and the main classes of responsive materials developed to date. Particular emphasis is placed on the wide-ranging possibilities(More)
A range of gene delivery vectors containing the thermoresponsive polymer, poly(N-isopropylacrylamide) (PNIPAm) was evaluated for effects on cell viability, intracellular trafficking and transgene expression in C2C12 mouse muscle cells. Polymers were complexed with plasmid DNA at pH 7.4 and the ability of the resulting particles to transfect cells was(More)
The exploitation of nature's machinery at length scales below the dimensions of a cell is an exciting challenge for biologists, chemists and physicists, while advances in our understanding of these biological motifs are now providing an opportunity to develop real single molecule devices for technological applications. Single molecule studies are already(More)
Poly(N-isopropylacrylamide) (PNIPAm) co-polymers responsive to temperature and pH were prepared with side chain chemistries in order to exhibit phase transitions under physiologically relevant conditions. Fluorescence spectroscopy, gel retardation assays, dynamic light scattering and atomic force microscopy were used to characterize the binding of plasmid(More)
Copolymers of N-isopropylacrylamide with a fluorescent probe monomer were grafted to branched poly(ethyleneimine) to generate polycations that exhibited lower critical solution temperature (LCST) behavior. The structures of these polymers were confirmed by spectroscopy, and their phase transitions before and after complexation with DNA were followed using(More)
BACKGROUND Successful non-viral gene targeting requires vectors to meet two conflicting needs-strong binding to protect the genetic material during transit and weak binding at the target site to enable release. Responsive polymers could fulfil such requirements through the switching of states, e.g. the chain-extended coil to chain-collapsed globule phase(More)
The conjugation of thermoresponsive polymers to multisubunit, multifunctional hybrid type 1 DNA restriction-modification (R-M) enzymes enables temperature-controlled "switching" of DNA methylation by the conjugate. Polymers attached to the enzyme at a subunit distal to the methylation subunit allow retention of DNA recognition and ATPase activity while(More)
Synthetic polycations have shown promise as gene delivery vehicles but suffer from an unacceptable toxicity and low transfection efficiency. Novel architectures are being explored to increase transfection efficiency, including copolymers with a thermoresponsive character. The physicochemical characterization of a family of copolymers comprising a core of(More)
A thermoresponsive polymer, N-isopropylacrylamide-co-acrylamide (Mn 6 kDa) with a lower critical solution temperature (LCST) of 37 degrees C, was activated and conjugated to avidin to yield a derivative with 200 kDa molecular weight. Gel permeation analysis demonstrated that the new bioconjugate possessed an apparent size corresponding to a 220 kDa globular(More)
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