@article { ISI:000313235300008,
	title = {4(R/S)-Amino/guanidino-substituted proline peptides: design, synthesis and DNA transfection properties},
	journal = {Chimia},
	volume = {66},
	number = {12, 1},
	year = {2012},
	month = {DEC},
	pages = {936-940},
	publisher = {SWISS CHEMICAL SOC},
	address = {SCHWARZTORSTRASSE 9, CH-3007 BERN, SWITZERLAND},
	abstract = {<p>Collagen is a major structural protein found in the connective tissues of higher organisms and mammals and its biomechanical properties are related to the high thermal stability of its triple helical structure. The primary structure of collagen is composed of the repeating tripeptide motif of Pro-Hyp-Gly, where Hyp is 4R-hydroxy proline. Cationic collagen mimetics consisting of [Pro(X)-Pro(Y)-Gly](6) where Pro(X) and Pro(Y) are 4(R/S)-amino/guanidine proline have been synthesized and shown to form triplexes more stable than the unmodified collagen peptide [Pro-Hyp-Gly](6). The origin of hyperstability is due to conformational pre-organization of proline pucker arising from the electronegativity of the cationic group. These cationic collagen peptides are shown to be effective cell penetrating and plasmid DNA transfecting agents. The results have potential for design of new collagen mimetics for biomaterial applications and efficient cell penetrating agents for drug delivery applications.</p>},
	keywords = {4-Aminoproline peptides, 4-Guanidino proline peptides, Cationic collagen mimetics, Cell penetrating peptides},
	issn = {0009-4293},
	doi = {10.2533/chimia.2012.936},
	author = {Umashankara, M. and Nanda, Manaswini and Sonar, Mahesh and Ganesh, Krishna N.}
}
@article { ISI:000377424600004,
	title = {Efficient cellular entry of (r-x-r)-type carbamate-plasmid DNA complexes and its implication for noninvasive topical DNA delivery to skin},
	journal = {Molecular Pharmaceutics},
	volume = {13},
	number = {6},
	year = {2016},
	month = {JUN},
	pages = {1779-1790},
	publisher = {AMER CHEMICAL SOC},
	address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA},
	abstract = {<p>Arginine-rich cell penetrating peptides are powerful tools for in vitro as well as in vivo delivery of a wide plethora of biomolecules. However, presence of consecutive arginine residues leads to enhanced amenability for proteolytic degradation as well as steric hindrances for membrane interactions which compromise its bioavailability. In order to overcome these limitations we previously reported a safe and stable octaarginine based oligomer, i.e., (r-x-r)4-carbamate, where the backbone amide linkages were replaced by carbamate linkages and 6-aminohexanoic acid based spacer moieties were incorporated for better flexibility, hydrophobicity, optimal spacing of guanidinium groups, and protection against proteolytic cleavage; resulting in improved transfection efficiency over its amide counterpart. In the present work we have investigated the mechanism behind this enhanced transfection efficiency and, based on our observations, demonstrate how the synergistic effect of rationalized oligomer designing, complex characteristics, and cell type contributes to overall effective intracellular delivery. Our results indicate that the (r-x-r)4-carbamate plasmid DNA complexes primarily utilize lipid raft dependent pathway of cellular entry more than other pathways, and this possibly facilitates their increased entry in the lipid raft rich milieu of skin cells. We also emphasize the utility of oligomer (r-x-r)4-carbamate as an efficient carrier for topical delivery of nucleic acids in skin tissue. This carrier can be utilized for safe, efficient, and noninvasive delivery of therapeutically relevant macromolecular hydrophilic cargo like nucleic acids to skin.</p>},
	keywords = {Cell penetrating peptides, endocytosis, nucleic acid delivery, skin penetration, transfection},
	issn = {1543-8384},
	doi = {10.1021/acs.molpharmaceut.5b00915},
	author = {Vij, Manika and Natarajan, Poornemaa and Yadav, Amit K. and Patil, Kiran M. and Pandey, Tanuja and Gupta, Nidhi and Santhiya, Deenan and Kumar, Vaijayanti A. and Fernandes, Moneesha and Ganguli, Munia}
}
