- Large chiral discrimination of a molecular probe by bovine serum albumin
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A phenylalanine-derived fluorescent probe shows high enantioselectivity for binding to bovine serum albumin; the L-isomer binds nearly one hundred times better than the D-isomer, which suggests the tight fitting of the L-isomer to the binding site.
- Kumar,Buranaprapuk,Sze
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- Pyrene-based fluorescent supramolecular hydrogel: scaffold for nanoparticle synthesis
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The present work illustrates the design and development of pyrene-based fluorescent supramolecular hydrogel consisting of l-phenylalanine residue as the linker and ethyleneoxy unit with free primary amine at C-terminal. The gelator efficiently immobilized
- Kar, Tanmoy,Patra, Nitai
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- Single amino acid based thixotropic hydrogel formation and pH-dependent morphological change of gel nanofibers
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A single amino acid (phenylalanine) based pyrene conjugated low molecular weight hydrogelator has been discovered. This amino acid derivative has been found to form hydrogels in a wide range of aqueous solutions of pH 7.46-14 and the estimated minimum gelation concentration (MGC) in phosphate buffer solution at physiological pH 7.46 is 0.037% (w/v) i.e. 0.85 mM. A transparent hydrogel has been produced in the pH range (7.46-10.5), while a translucent hydrogel has been formed at higher pH. The hydrogel has been characterized by field emission scanning electron microscopy (FE-SEM), fluorescence microscopy, differential scanning calorimetry (DSC), circular dichroism (CD), X-ray diffraction (XRD) and rheological studies. A distinct morphological change of the gel nanofibers from helical to tape-like morphology has been noticed in the FE-SEM studies with an increase in pH. These observations have been supported by a significant decrease of the CD signals and different XRD patterns found with the increase in pH. Interestingly, this hydrogel shows a pH dependent thixotropic property. The thixotropic property of the hydrogel has been examined using rheological experiments. This thixotropic property of the hydrogel has been utilized for the encapsulation of vitamin B12 and an anticancer drug, doxorubicin, in the hydrogel matrix without any heating-cooling cycle and sustained release of these bioactive molecules has been studied at physiological temperature (37 °C) and pH (7.46) over a period of about 3 days.
- Nanda, Jayanta,Biswas, Abhijit,Banerjee, Arindam
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- Site-specific photocleavage of proteins
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Bovine serum albumin and chicken-egg lysozyme can be cleaved with high specificity into two fragments by the method shown below. A pyrene-L-phenylalanine conjugate was used as the probe (shown schematically over the first arrow), which binds with site spe
- Kumar,Buranaprapuk
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- A tryptophan-containing fluoroionophore sensor with high sensitivity to and selectivity for lead ion in water
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We report herein a fluoroionophore sensor derivated from tryptophan that shows high sensitivity (detection limit up to 0.15 μM) and specific selectivity for lead ion (Pb2+) over Ca2+, Cd 2+, Co2+, Cr3+, Cu2+, K+, Mg2+, Na+, Fe2+, Mn2+, Ni 2+ and Zn2+ in aqueous solution. The Royal Society of Chemistry 2006.
- Ma, Li-Jun,Liu, Yi-Fu,Wu, Yuqing
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- X???X Halogen Bond-Induced Supramolecular Helices
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The halogen bond is the attractive interaction between the electrophilic region of a halogen atom and the nucleophilic region of another molecular entity, emerging as a favorable manner to manipulate supramolecular chirality in self-assemblies. Engineerin
- Hao, Aiyou,Xing, Pengyao,Xu, Yunying
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supporting information
(2021/11/30)
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- A biocompatible hydrogel as a template for oxidative decomposition reactions: A chemodosimetric analysis and in vitro imaging of hypochlorite
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The self-assembly properties of new biocompatible, thermoreversible fluorescent hydrogels, composed of amino acid residues, e.g., l-phenylalanine (PyL-PheOx) and l-tyrosine (PyL-TyrOx), have been reported. Spectroscopic investigations indicate that PyL-PheOx forms π-stacked 'compact' aggregates, while 'loose' aggregates with stronger CT characteristics are observed for PyL-TyrOx. Both the compounds showed the presence of fibrous networks in the self-assembled state. Circular dichroism spectral studies indicate the formation of M-helical and P-helical structures for PyL-PheOx and PyL-TyrOx, respectively. A striking gel-to-sol transition, caused by oxidative decomposition, is explicitly noticed in the presence of hypochlorite. A mechanistic investigation reveals the oxidation of the acyl aroyl hydrazine core of the gelators in the presence of ClO-. In addition to this, change in the fluorescence emission intensity of the hydrogel in the presence of ClO- is utilized for the analysis of commercial bleach samples. Gel-coated paper strips are also developed for the on-site detection of ClO-. Furthermore, the system is utilized for imaging hypochlorite in live mammalian cells. This journal is
- Bhattacharya, Santanu,Biswakarma, Dipen,Dey, Nilanjan
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p. 2286 - 2295
(2022/03/08)
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- Designer Outer Membrane Protein Facilitates Uptake of Decoy Molecules into a Cytochrome P450BM3-Based Whole-Cell Biocatalyst
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We report an OmpF loop deletion mutant, which improves the cellular uptake of external additives into an Escherichia coli whole-cell biocatalyst. Through co-expression of the OmpF mutant with wild-type P450BM3 in the presence of decoy molecules, the yield
- Karasawa, Masayuki,Shoji, Osami,Stanfield, Joshua Kyle,Suzuki, Kazuto,Yonemura, Kai
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supporting information
(2021/12/16)
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- Hydrophobic End-Modulated Amino-Acid-Based Neutral Hydrogelators: Structure-Specific Inclusion of Carbon Nanomaterials
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Hydrophobic end-modulated l-phenylalanine-containing triethylene glycol monomethyl ether tagged neutral hydrogelators (1-4) are developed. Investigations determine the gelators' structure-dependent inclusion of carbon nanomaterials (CNMs) in the self-assembled fibrillar network (SAFIN). The gelators (1, 3, and 4) can immobilize water and aqueous buffer (pH3-7) with a minimum gelator concentration of 10-15mg mL-1. The hydrophobic parts of the gelators are varied from a long chain (C-16) to an extended aromatic pyrenyl moiety, and their abilities to integrate 1 D and 2 D allotropes of carbon (i.e., single-walled carbon nanotubes (SWNTs) and graphene oxide (GO), respectively) within the gel are investigated. Gelator1, containing a long alkyl chain (C-16), can include SWNTs, whereas the pyrene-containing 4 can include both SWNTs and GO. Gelator3 fails to incorporate SWNTs or GO owing to its slow rate of gelation and possibly a mismatch between the aggregated structure and CNMs. The involvement of various forces in self-aggregated gelation and physicochemical changes occurring through CNM inclusion are examined by spectroscopic and microscopic techniques. The distinctive pattern of self-assembly of gelators1 and 4 through J- and H-type aggregation might facilitate the structure-specific CNM inclusion. Inclusion of SWNTs/GO within the hydrogel matrix results in a reinforcement in mechanical stiffness of the composites compared with that of the native hydrogels.
- Choudhury, Pritam,Mandal, Deep,Brahmachari, Sayanti,Das, Prasanta Kumar
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supporting information
p. 5160 - 5172
(2016/04/09)
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- Phenylboronic Acid Appended Pyrene-Based Low-Molecular-Weight Injectable Hydrogel: Glucose-Stimulated Insulin Release
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A pyrene-containing phenylboronic acid (PBA) functionalized low-molecular-weight hydrogelator was synthesized with the aim to develop glucose-sensitive insulin release. The gelator showed the solvent imbibing ability in aqueous buffer solutions of pH valu
- Mandal, Deep,Mandal, Subhra Kanti,Ghosh, Moumita,Das, Prasanta Kumar
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supporting information
p. 12042 - 12052
(2015/08/18)
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- Pyrene-based fluorescent ambidextrous gelators: Scaffolds for mechanically robust swnt-gel nanocomposites
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With the rapid progress in the development of supramolecular soft materials, examples of low-molecularweight gelators (LMWGs) with the ability to immobilise both water and organic solvents by the same structural scaffold are very limited. In this paper, we report the development of pyrene-containing peptide-based ambidextrous gelators (AGs) with the ability to efficiently gelate both organic and aqueous solvents. The organo-and hydrogelation efficiencies of these gelators are in the range 0.7-1.1% w/v in various organic solvents and 0.5-5% w/v in water at certain acidic pH values (pH 2.0-4.0). Moreover, for the first time, AGs have been utilised to prepare single-walled carbonnanotube (SWNT)-included soft nanocomposites in both hydro-and organogel matrices. The influence of different non-covalent interactions such as hydrogen bonding, hydrophobic, p-p and van der Waals interactions in self-assembled gelation has been studied in detail by circular dichroism, FTIR, variable-temperature NMR, 2D NOESY and luminescence spectroscopy. Interestingly, the presence of the pyrene moiety in the structure rendered these AGs intrinsically fluorescent, which was quenched upon successful integration of the SWNTs within the gel. The prepared hydroand organogels along with their SWNT-integrated nanocomposites are thermoreversible in nature. The supramolecular morphologies of the dried gels and SWNT-gel nanocomposites have been studied by transmission electron microscopy, fluorescence microscopy and polarising optical microscopy, which confirmed the presence of three-dimensional self-assembled fibrillar networks (SAFINs) as well as the integrated SWNTs. Importantly, rheological studies revealed that the inclusion of SWNTs within the ambidextrous gels improved the mechanical rigidity of the resulting soft nanocomposites up to 3.8-fold relative to the native gels.
- Mandal, Deep,Kar, Tanmoy,Das, Prasanta Kumar
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supporting information
p. 1349 - 1358
(2014/04/03)
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- Delivery of floxuridine derivatives to cancer cells by water-soluble organometallic cages
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The self-assembly of 2,4,6-tris(pyridin-4-yl)-1,3,5-triazine (tpt) triangular panels with p-cymene (pPriC6H4Me) ruthenium building blocks and 2,5-dioxydo-1,4-benzoquinonato (dobq) or 5,8-dioxydo-1,4-naphthoquinonato (donq) bridges, in the presence of a pyrenyl-nucleoside derivatives (pyreneR), affords the triangular prismatic host-guest compounds [(pyrene-R)?Ru6(pPriC 6H4Me)6(tpt)2(dobq) 3]6+ ([(pyrene-R)?1]6+) and [(pyrene-R)?Ru6(pPriC6H4Me) 6(tpt)2(donq)3]6+ ([(pyrene-R)?2]6+), respectively. The inclusion of six monosubstitutedpyrenyl-nucleosides (pyrene-R1 = 5′-(1-pyrenyl butanoate)-2′-deoxyuridine, pyrene-R2 = 5-fluoro-5′-(1-pyrenyl butanoate)-2′-deoxyuridine, pyrene-R3 = 5′-{N-[1-oxo-4-(1-pyrenyl) butyl]-glycyl}-2′-deoxyuridine, pyrene-R4 = 5-fluoro-5′-{N-[1-oxo-4- (1-pyrenyl)butyl]-glycyl}-2′-deoxyuridine, pyrene-R5 = 5-fluoro-5′-{N-[1-oxo-4-(1-pyrenyl)butyl]-phenylalanyl} -2′-deoxyvuridine, pyrene-R6 = 5-fluoro-5′-{N-[1-oxo-4-(1-pyrenyl) butyl]-phenylalanyl}-2′-deoxyuridine) has been accomplished. The carceplex nature of [(pyrene-R)?1]6+ with the pyrenyl moiety firmly encapsulated in the hydrophobic cavity of the cage with the nucleoside groups pointing outward was confirmed by NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS), while the host-guest nature of [(pyrene-R)?2] 6+ was studied in solution by NMR techniques. In contrast to the floxuridine compounds used in the clinic, the host-guest complexes are highly water-soluble. Consequently, the cytotoxicities of these water-soluble compounds have been established using human ovarian A2780 and A2780cisR cancer cells. All the host-guest systems are more cytotoxic than the empty cages alone [1][CF3SO3]6 (IC50 = 23 μM) and [2][CF3SO3]6 (IC50 = 10 μM), the most active compound [pyrene-R4?1][CF3SO3] 6being 2 orders of magnitude more cytotoxic (IC50 = 0.3 μM) on these human ovarian cancer cell lines (A2780 and A2780cisR).
- Yi, Jeong Wu,Barry, Nicolas P. E.,Furrer, Mona A.,Zava, Olivier,Dyson, Paul J.,Therrien, Bruno,Kim, Byeang Hyean
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p. 461 - 471
(2012/06/04)
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