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134 results on '"Kulkarni, Ketav"'

1. A strategy for covalent anchoring of self-assembling β3 oligoamide nanorods to gold surfaces

Author

Hussein Khadeeja A., Kulkarni Ketav, Barlow Anders, Perlmutter Patrick, and Mechler Adam

Subjects
substituted oligoamide, gold binding, self-assembly, hetero-assembly, Biotechnology, TP248.13-248.65
Abstract

Oligopeptides stand out for their remarkable structural variability, ease of synthesis, and amenability to functionalization, making them exceedingly appealing for crafting functional nanostructured materials. The low metabolic stability of natural peptides can be overcome by replacing α-amino acids with β3- amino acids, to yield artificial peptides best described as substituted β3-oligoamides. Controlling the morphology of such structures by varying the amino acid residues and altering the oligoamide termini makes it possible to adapt the core design to a range of hierarchical structures and function. Conductivity is a desired property in such nanomaterials; preferably conductive materials should be chemically anchored to a highly conductive metal, such as gold surface to connect to macroscopic electronics. It is preferable to use thiol functionality, however β3 cysteine is not synthetically achieveable. In this study β3 [SLIA] oligoamide has been synthesized and functionalized at the N terminus with a thiol moiety. After successful synthesis and purification, the thiolated oligoamide was physically characterized to confirm binding to gold, self-assembly and hetero assembly on these anchor points. It was demonstrated with a quartz crystal microbalance (QCM) that self-assembling monolayers can be formed on a gold surface and the formation of a S-Au bond was confirmed with X-ray photoelectron spectroscopy. Growth of Ac-β3[WKLWEL] fibres on these anchor points was confirmed by using atomic force microscopy and QCM. Hence, a viable metal anchor has been established that lays the foundations for the future development of molecular electronics based on β3 oligoamides.

Published
2024
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4. A strategy for covalent anchoring of self-assembling β3 oligoamide nanorods to gold surfaces.

Author

Hussein, Khadeeja A., Kulkarni, Ketav, Barlow, Anders, Perlmutter, Patrick, and Mechler, Adam

Subjects
OLIGOPEPTIDES, NANORODS, NANOSTRUCTURED materials, ATOMIC force microscopy, X-ray photoelectron spectroscopy
Abstract

Oligopeptides stand out for their remarkable structural variability, ease of synthesis, and amenability to functionalization, making them exceedingly appealing for crafting functional nanostructured materials. The low metabolic stability of natural peptides can be overcome by replacing α-amino acids with β3- amino acids, to yield artificial peptides best described as substituted β3-oligoamides. Controlling the morphology of such structures by varying the amino acid residues and altering the oligoamide termini makes it possible to adapt the core design to a range of hierarchical structures and function. Conductivity is a desired property in such nanomaterials; preferably conductive materials should be chemically anchored to a highly conductive metal, such as gold surface to connect to macroscopic electronics. It is preferable to use thiol functionality, however β3 cysteine is not synthetically achieveable. In this study β3 [SLIA] oligoamide has been synthesized and functionalized at the N terminus with a thiol moiety. After successful synthesis and purification, the thiolated oligoamide was physically characterized to confirm binding to gold, self-assembly and hetero assembly on these anchor points. It was demonstrated with a quartz crystal microbalance (QCM) that self-assembling monolayers can be formed on a gold surface and the formation of a S-Au bond was confirmed with X-ray photoelectron spectroscopy. Growth of Ac-β3[WKLWEL] fibres on these anchor points was confirmed by using atomic force microscopy and QCM. Hence, a viable metal anchor has been established that lays the foundations for the future development of molecular electronics based on β3 oligoamides. [ABSTRACT FROM AUTHOR]

Published
2024
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10. Esterase-Mediated Sustained Release of Peptide-Based Therapeutics from a Self-Assembled Injectable Hydrogel

Author

Kulkarni, Ketav, primary, Minehan, Rachel L., additional, Gamot, Tanesh, additional, Coleman, Harold A., additional, Bowles, Simon, additional, Lin, Qingqing, additional, Hopper, Denham, additional, Northfield, Susan E., additional, Hughes, Richard A., additional, Widdop, Robert E., additional, Aguilar, Marie-Isabel, additional, Parkington, Helena C., additional, and Del Borgo, Mark P., additional

Published
2021
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18. Correction: A two-dimensional metallosupramolecular framework design based on coordination crosslinking of helical oligoamide nanorods

Author

West, Norton G., primary, Seoudi, Rania S., additional, Barlow, Anders J., additional, Qi, Dongchen, additional, Puskar, Ljiljana, additional, Del Borgo, Mark P., additional, Kulkarni, Ketav, additional, Adda, Christopher G., additional, Pan, Jisheng, additional, Aguilar, Marie-Isabel, additional, Perlmutter, Patrick, additional, and Mechler, Adam, additional

Published
2020
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19. A two-dimensional metallosupramolecular framework design based on coordination crosslinking of helical oligoamide nanorods

Author

West, Norton G., primary, Seoudi, Rania S., additional, Barlow, Anders J., additional, Qi, Dongchen, additional, Puskar, Ljiljana, additional, Del Borgo, Mark P., additional, Kulkarni, Ketav, additional, Adda, Christopher G., additional, Pan, Jisheng, additional, Aguilar, Marie-Isabel, additional, Perlmutter, Patrick, additional, and Mechler, Adam, additional

Published
2020
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20. Evaluation of cyclic peptide inhibitors of the Grb7 breast cancer target: Small change in cargo results in large change in cellular activity

Author

Sang, Jianrong, Kulkarni, Ketav, Watson, Gabrielle, Ma, Xiuquan, Craik, David, Troeira Henriques, Sonia, Poth, Aaron, Benfield, Aurelie, Wilce, Jacqueline, Sang, Jianrong, Kulkarni, Ketav, Watson, Gabrielle, Ma, Xiuquan, Craik, David, Troeira Henriques, Sonia, Poth, Aaron, Benfield, Aurelie, and Wilce, Jacqueline

Abstract

Grb7 is an adapter protein, overexpressed in HER2+ve breast and other cancers, and identified as a therapeutic target. Grb7 promotes both proliferative and migratory cellular pathways through interaction of its SH2 domain with upstream binding partners including HER2, SHC, and FAK. Here we present the evaluation of a series of monocyclic and bicyclic peptide inhibitors that have been developed to specifically and potently target the Grb7 SH2-domain. All peptides tested were found to inhibit signaling in both ERK and AKT pathways in SKBR-3 and MDA-MB-231 cell lines. Proliferation, migration, and invasion assays revealed, however, that the second-generation bicyclic peptides were not more bioactive than the first generation G7-18NATE peptide, despite their higher in vitro affinity for the target. This was found not to be due to steric hindrance by the cell-permeability tag, as ascertained by ITC, but to differences in the ability of the bicyclic peptides to interact with and penetrate cellular membranes, as determined using SPR and mass spectrometry. These studies reveal that just small differences to amino acid composition can greatly impact the effectiveness of peptide inhibitors to their intracellular target and demonstrate that G7-18NATE remains the most effective peptide inhibitor of Grb7 developed to date.

Published
2019

24. Surface acoustic waves in chemistry and the total synthesis of the pervilleines

Author

Kulkarni, Ketav Prakash

Subjects
humanities, Uncategorized
Abstract

Chapter one provides background information on the physical basis and design principles of SAW-based devices. Specifically, it explains the transmission of SAWs through viscous fluids, fabrication of the SAW devices, and the underlying physics in determining the resonant frequency of the SAW device. SAWs are analogous to earthquake waves which travel on the surface of a piezoelectric substrate at the speed of sound. Generation of SAWs was accomplished by using a pair of metal electrodes called IDTs. Micro-fabrication methods, involving sputtering and photolithography, were used to fabricate the SAW devices. The devices were then tested for their resonant frequency by impedance analysis. Chapter two describes the use of SAWs as an energy source for drop-scale chemical reactions. Chemical reagents were loaded on the surface of a piezoelectric substrate in the form of a drop. SAWs were generated on the substrate surface by applying a sinusoidal oscillating electrical signal to a pair of IDTs. The viscous reaction fluid absorbed the SAWs, producing an internal streaming pattern within the reaction drop. Turbulent flow generated by this streaming resulted in heating and stirring of the drop. Chapter two also illustrates the use of SAWs as an energy source in implementing batch process chemistry on a laboratory scale. The reactions were carried out in a closed-vessel glass reactor, typically a flat-bottomed and screw-capped vial. A liquid couplant was employed to enhance the transfer of SAW energy from the piezoelectric substrate to the reaction vessel. Under these conditions, the SAWs were transmitted into the liquid couplant, as bulk sound waves, which facilitated the propagation of Lamb waves in the base of the reaction vessel. These Lamb waves then transmitted the acoustic energy into the reaction solution within the vessel. A range of diverse reactions were attempted using this lab-on-a-chip setup utilising SAWs as the source of energy. Chapter three outlines a new modality for in-gel sample processing and tryptic digestion of proteins using a SAW device. Sample preparation, rehydration, in situ digestion and peptide extraction from gel slices or spots was accelerated by placing the material on a piezoelectric substrate and treating the gel slice, immersed in reagent solutions, with SAWs. The SAW assisted in-gel digestion produced chromatograms of similar coverage and intensity to those observed for traditional processing and overnight digestion in only 30 min. Chapter four describes the enantioselective synthesis of pervilleine C, exploiting aspects of the [4+3] cycloaddition and Brown’s enantioselective oxidative hydroboration. Esterification then completed total syntheses of pervilleine C and its enantiomer. These short syntheses provide an expedient route to pervilleine and select analogues to assist in the elucidation of the pervilleine pharmacophore, and to afford sufficient quantities of the pervilleines for their biological evaluation as MDR reversal agents in MDR cancer cell lines.

Published
2017
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31. Supramolecular self-assembly of N-acetyl Beta3-peptide amphiphiles

Author

Del Borgo Mark, Aguilar Mibel, Kulkarni Ketav, Lee Tzong-Hsien, and Habila Nathan

Subjects
chemistry.chemical_classification, Histology, chemistry, Stereochemistry, Amphiphile, Biomedical Engineering, Supramolecular chemistry, Bioengineering, Peptide, Self-assembly, Biotechnology
Published
2016

40. Cyclic Peptides Incorporating Phosphotyrosine Mimetics as Potent and Specific Inhibitors of the Grb7 Breast Cancer Target

Author

Watson, Gabrielle M., primary, Gunzburg, Menachem J., additional, Ambaye, Nigus D., additional, Lucas, William A. H., additional, Traore, Daouda A., additional, Kulkarni, Ketav, additional, Cergol, Katie M., additional, Payne, Richard J., additional, Panjikar, Santosh, additional, Pero, Stephanie C., additional, Perlmutter, Patrick, additional, Wilce, Matthew C. J., additional, and Wilce, Jacqueline A., additional

Published
2015
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44. Unique Functional Materials Derived from b-Amino Acid Oligomers.

Author

Del Borgo, Mark P., Kulkarni, Ketav, and Aguilar, Marie-Isabel

Subjects
*OLIGOMERS -- Structure, *AMINO acids, *PEPTIDES
Abstract

The unique structures formed by β-amino acid oligomers, or β-peptide foldamers, have been studied for almost two decades, which has led to the discovery of several distinctive structures and bioactive molecules. Recently, this area of research has expanded from conventional peptide drug design to the formation of assemblies and nanomaterials by peptide self-assembly. The unique structures formed by β-peptides give rise to a set of new materials with altered properties that differ from conventional peptide-based materials; such new materials may be useful in several bio- and nanomaterial applications. [ABSTRACT FROM AUTHOR]

Published
2017
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46. Orthogonal strategy for the synthesis of dual-functionalised β3-peptide based hydrogels.

Author

Kulkarni, Ketav, Motamed, Sepideh, Habila, Nathan, Perlmutter, Patrick, Forsythe, John S., Aguilar, Marie-Isabel, and Del Borgo, Mark P.

Subjects
*HYDROGELS, *ORTHOGONALIZATION, *SOLID-phase synthesis, *PEPTIDES, *MOLECULAR self-assembly, *OLIGOMERS
Abstract

We have described a new class of hydrogelator based on helical β3-peptides carrying a bioactive payload. The β3-peptides self-assemble in aqueous solution to form a nanofibrous mesh resulting in a stable hydrogel. The simple design provides the versatility for attaching different functional payloads to the β3-peptide scaffold to develop new materials. [ABSTRACT FROM AUTHOR]

Published
2016
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47. Decorated self-assembling β3-tripeptide foldamers form cell adhesive scaffolds.

Author

Luder, Kerstin, Kulkarni, Ketav, Lee, Huey Wen, Widdop, Robert E., Del Borgo, Mark P., and Aguilar, Marie-Isabel

Subjects
*BIOMATERIALS, *TRIPEPTIDES, *NANOFIBERS, *CELL growth, *PEPTIDES
Abstract

A popular strategy to control cellular growth and differentiation is the employment of self-assembling peptides as biomaterials. In this study we decorated ultrashort helical N-acetylated β-tripeptides with cell adhesion signals IKVAV and RGD, which spontaneously self-assemble to give nanofibres with multiple signals, and form a bioscaffold that supports the growth of cells. [ABSTRACT FROM AUTHOR]

Published
2016
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48. Light-triggered release of ciprofloxacin from an in situ forming click hydrogel for antibacterial wound dressings.

Author

Truong, Vinh X., Simon, George P., Forsythe, John S., Shi, Yue, Kulkarni, Ketav, Perlmutter, Patrick, Qu, Yue, Lithgow, Trevor, and Boyd, Richard L.

Abstract

Light triggered release of an antibiotic from a click crosslinked hydrogel was developed by conjugating ciprofloxacin through a photo-cleavable linker to the hydrogel network structure. Upon irradiation of the hydrogel material with UV light (365 nm) at low intensity, native ciprofloxacin was released into the surrounding environment and could be detected by HPLC. The antimicrobial activity of the released compound on Staphylococcus aureus was demonstrated. [ABSTRACT FROM AUTHOR]

Published
2015
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