25 research outputs found
Self Assembling Peptides and Amino Acids based Soft Materials: Functional Gels and Charge Transfer Complexes
No full textThis thesis describes the formation of supramolecular hydrogels and organogels from different synthetic amino acid based amphiphiles and semiconducting organic moiety named naphthalenediimide appended peptide based derivatives. Amino acid and peptide derivatives have been synthesized, purified, characterized and studied in details. Their gelation ability in different aqueous and organic (aromatic/aliphatic) solvents has been studied extensively. These gelator molecules self-associated using various non-covalent interactions including intermolecular hydrogen bonds, electrostatic interactions, - staking etc. to form fibrillar assembly that can encapsulate solvent molecules into their interstitial pores to form self-supported gels. These gel materials have been characterized morphologically, structurally and rheologically. Furthermore, different kinds of applications of these gel materials have been explored.Research was carried out under the supervision of Prof. Arindam Banerjee of the Biological Chemistry division under SBS [School of Biological Sciences]Research was conducted under CSIR fellowshi
Recommended from our members
A tripeptide-based self-shrinking hydrogel for waste-water treatment: removal of toxic organic dyes and lead (Pb2+) ions
No full textA triphenylalanine-based superhydrogel shows automatic syneresis (self-compressing properties) with time and this self-shrinking behavior has been successfully utilized to remove toxic lead ions and organic dyes from waste-water efficiently with the ability to re-use for a few times
Formation of Hybrid Hydrogels Consisting of Tripeptide and Different Silver Nanoparticle-Capped Ligands: Modulation of the Mechanical Strength of Gel Phase Materials
No full textAn N-terminally Boc (tert-butyloxycarbonyl) group-protected synthetic tripeptide (Boc-Phe-Phe-Ala–OH) has been found to form a translucent hydrogel in basic aqueous medium. This hydrogel material has been characterized using field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transformed infrared spectroscopy, differential scanning calorimetric, X-ray diffraction (XRD), and rheological studies. FE-SEM and TEM studies have revealed the formation of a nanofibrillar network structure upon gelation. Thiol (-SH) containing ligands (amino acid/peptide) have been used to stabilize small silver nanoparticles (AgNPs), and these thiol-capped silver nanoparticles have been incorporated into this hydrogel to prepare hybrid hydrogels. Morphological study of silver nanoparticles containing a hybrid hydrogel (using TEM experiments) has indicated the nice fabrication of AgNPs along the gel nanofibers. Fabrication of nanoparticles upon the gel nanofibers is due to noncovalent interactions between the capping ligands of the nanoparticles and the peptide-based hydrogel nanofibers. Rheological investigations of these hybrid hydrogels have shown the weakening of the mechanical strength of the hydrogel after incorporation of AgNPs within the native hydrogel system. Our studies have vividly shown the dependence of the elastic modulus (G′) and yield stress (σy) on three factors: (a) the nature of the stabilizing ligands used for AgNPs, (b) the size of the AgNPs, and (c) the amount of AgNPs used for the preparation of hybrid hydrogel systems. Modulation of the mechanical strength of the hybrid hydrogel can be successfully achieved by varying these above-mentioned factors. This modulation of the mechanical properties keeps a future promise to make tunable soft materials with interesting properties
Luminescent Naphthalene Diimide-Based Peptide in Aqueous Medium and in Solid State: Rewritable Fluorescent Color Code
No full textThis study convincingly demonstrates a unique example of the self-assembly of a naphthalene diimide (NDI)-appended peptide into a fluorescent J-aggregate in aqueous media. Moreover, this aggregated species shows a remarkable yellow fluorescence in solid state, an unusual phenomenon for NDI-based compounds. The aggregated species has been characterized using transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy, X-ray diffraction, time-correlated single proton counting (TCSPC), UV–vis, and photoluminescence studies. TEM images reveal cross-linked nanofibrillar morphology of this aggregated species in water (pH 7.4). TCSPC study clearly indicates that the aggregated species in water has a higher average lifetime compared to that of the non-aggregated species. Interestingly, this NDI-based peptide shows H⁺ ion concentration-dependent change in the emission property in water. The fluorescence output is erased completely in the presence of an alkali, and it reappears in the presence of an acid, indicating its erasing and rewritable property. This indicates its probable use in authentication tools for security purposes as a rewritable fluorescence color code. This NDI-appended peptide-based molecule can be used for encryption of information due to erasing and rewritable property of the molecule in the aggregated state in aqueous medium
Multi-stimuli responsive self-healing metallo-hydrogels: tuning of the gel recovery property
No full textA series of amphiphilic tyrosine based self-healable, multi-stimuli responsive metallo-hydrogels have been discovered. Formation of these hydrogels is highly selective to Ni2+ ions. The self-healing property and the stiffness of these metallo-hydrogels can be tuned by varying the chain length of the corresponding gelator amphiphile
Assembly of naphthalenediimide conjugated peptides: aggregation induced changes in fluorescence
No full textNaphthalenediimide appended peptide based self-assembly was studied. Interestingly, an aggregation induced drastic change in the fluorescence property and gel formation were observed depending on the solvent composition (chloroform : methylcyclohexane) at a fixed concentration of 1.6 mM at room temperature
Selective binding of hydrogen chloride and its trapping through supramolecular gelation
No full textA pyridine containing amino acid based gelator forms gel in aqueous media in the presence of hydrochloric acid and the chloride ion is found to be very selective for gelation. The gelator is successfully applied for the detection and trapping of hydrogen chloride gas and this indicates its probable application for removing hazardous HCl gas from the environment
A new aromatic amino acid based organogel for oil spill recovery
No full textAn aromatic amino acid (phenylglycine) based amphiphile with amide and ester groups and a long fatty acyl chain has been found to form organogels selectively in the fuel hydrocarbon solvents including hexane, heptane, cyclohexane, diesel, kerosene and pump-oil at room temperature. Organogels have been well characterized morphologically by field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). Morphological studies of these xerogels have revealed the presence of fascinating right-handed twisted nanoribbons (in n-heptane and n-octane). Involvement of different non-covalent interactions among the gelator molecules within the gel matrix has been studied using FT-IR and XRD. The organogel in diesel is mechanically stable with high yield stress (177.8 Pa) and storage modulus (>104 Pa) values, as has been evidenced from the rheological studies. Interestingly, this gelator compound exhibits phase selective gelation properties and the phase selective gelation occurs efficiently and quickly (within 90 s), in oil–water mixtures and the gelator molecule can be recovered and reused several times easily, indicating its applicability in oil spill cleaning
