51
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Characterization of poly-d-mannuronate and poly-l-guluronate block fractions from sodium alginate and preparation of hydrogels with poly(vinylalcohol). Int J Biol Macromol 2018; 111:935-946. [DOI: 10.1016/j.ijbiomac.2018.01.097] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 12/27/2017] [Accepted: 01/14/2018] [Indexed: 12/29/2022]
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52
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Christ E, Collin D, Lamps JP, Mésini PJ. Variable temperature NMR of organogelators: the intensities of a single sample describe the full phase diagram. Phys Chem Chem Phys 2018; 20:9644-9650. [PMID: 29582031 DOI: 10.1039/c8cp00009c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Organogelators constitute a numerous class of compounds, able to form gels in organic solvents. Their phase diagrams are useful to understand their mechanisms of formation and their stability, but their mapping is often a tedious task. We show that liquid NMR can simplify and quicken the acquisition of phase diagrams. In liquid NMR spectra of organogels, the visible signals of the gelator represent only its soluble fraction. The intensities increase with temperature, until the gel melts. Suitable normalization of these intensities yields the solubility as a function of temperature, which is sufficient to map the phase diagram. We verified it experimentally with three organogelators, chosen because independent authors have previously mapped out their phase diagram by other techniques including DSC and rheology. We show that the curves obtained by NMR superimpose with these diagrams. A variable temperature NMR experiment with a single sample can yield the phase diagram with sensitivity of the order of 0.01 wt%.
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Affiliation(s)
- Elliot Christ
- Institut Charles Sadron, Université de Strasbourg, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex, France.
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53
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Edwards W, Smith DK. Chiral Assembly Preferences and Directing Effects in Supramolecular Two-Component Organogels. Gels 2018; 4:gels4020031. [PMID: 30674807 PMCID: PMC6209267 DOI: 10.3390/gels4020031] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 03/23/2018] [Accepted: 03/25/2018] [Indexed: 12/31/2022] Open
Abstract
The impact of chirality on the self-assembly of supramolecular gels is of considerable importance, as molecular-scale programming can be translated into nanostructuring and ultimately affect macroscopic performance. This paper explores the effect of chirality on the assembly of two-component gels comprised of a second-generation dendritic lysine peptide acid, containing three chiral centres, and an amine. This combination forms an acid⁻amine complex that assembles into nanofibres through peptide-peptide hydrogen bonds, leading to organogels. With achiral amines, a racemic mixture of l,l,l and d,d,d dendritic peptide acids surprisingly forms the best gels-more commonly, mixing enantiomers suppresses gelation. Thermodynamic studies demonstrate that depending on the amine, the greater stability of heterochiral gels can either be entropically or enthalpically driven. With amines possessing "R" chirality, the l,l,l peptide acid consistently forms more effective gels than its d,d,d analogue. Furthermore, in mixed gels, l,l,l sometimes imposes its assembly preference onto d,d,d. In summary, this paper demonstrates a rare example in which heterochiral gels are preferred, and also explores directing effects when each component in a two-component gel is chiral.
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Affiliation(s)
- William Edwards
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
| | - David K Smith
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
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54
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Yang Y, Reipa V, Liu G, Meng Y, Wang X, Mineart KP, Prabhu VM, Shi W, Lin NJ, He X, Sun J. pH-Sensitive Compounds for Selective Inhibition of Acid-Producing Bacteria. ACS APPLIED MATERIALS & INTERFACES 2018; 10:8566-8573. [PMID: 29436821 PMCID: PMC6852659 DOI: 10.1021/acsami.8b01089] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Stimuli-responsive compounds that provide on-site, controlled antimicrobial activity promise an effective approach to prevent infections, reducing the need for systemic antibiotics. We present a novel pH-sensitive quaternary pyridinium salt (QPS), whose antibacterial activity is boosted by low pH and controlled by adjusting the pH between 4 and 8. Particularly, this compound selectively inhibits growth of acid-producing bacteria within a multispecies community. The successful antibacterial action of this QPS maintains the environmental pH above 5.5, a threshold pH, below which demineralization/erosion takes place. The design, synthesis, and characterization of this QPS and its short-chain analogue are discussed. In addition, their pH-sensitive physicochemical properties in aqueous and organic solutions are evaluated by UV-vis spectroscopy, dynamic light scattering, and NMR spectroscopy. Furthermore, the mechanism of action reveals a switchable assembly that is triggered by acid-base interaction and formed by tightly stacked π-conjugated systems and base moieties. Finally, a model is proposed to recognize the correlated but different mechanisms of pH sensitivity and acid-induced, pH-controlled antibacterial efficacy. We anticipate that successful application of these QPSs and their derivatives will provide protections against infection and erosion through targeted treatments to acid-producing bacteria and modulation of environmental pH.
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Affiliation(s)
- Yin Yang
- Volpe Research Center, American Dental Association Foundation, Gaithersburg, MD 20899, USA
| | - Vytas Reipa
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Guo Liu
- School of Dentistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Yuan Meng
- Volpe Research Center, American Dental Association Foundation, Gaithersburg, MD 20899, USA
| | - Xiaohong Wang
- Volpe Research Center, American Dental Association Foundation, Gaithersburg, MD 20899, USA
| | - Kenneth P. Mineart
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Vivek M. Prabhu
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Wenyuan Shi
- Forsyth Institute, 245 First Street, Cambridge, Massachusetts 02142, USA
| | - Nancy J. Lin
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Xuesong He
- Forsyth Institute, 245 First Street, Cambridge, Massachusetts 02142, USA
- Corresponding Author and
| | - Jirun Sun
- Volpe Research Center, American Dental Association Foundation, Gaithersburg, MD 20899, USA
- Corresponding Author and
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55
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Prusinowska N, Szymkowiak J, Kwit M. Enantiopure Tertiary Urea and Thiourea Derivatives of Trianglamine Macrocycle: Structural Studies and Metallogeling Properties. J Org Chem 2018; 83:1167-1175. [PMID: 29310432 DOI: 10.1021/acs.joc.7b02600] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Synthesis and detailed experimental and theoretical study on new urea and thiourea derivatives of chiral trianglamine are presented. In solution, the urea derivative of the trianglamine adopts cone conformation, whereas a respective thiourea derivative exists in solution predominantly as a partial cone conformer. In the crystalline phase, the thiourea trianglamine derivative adapts partial cone conformation. In the solid state, the two symmetry independent molecules of thiourea trianglamine create bilayers, containing molecules arranged in a zipper motif. The bilayers are separated by channels filled with disordered solvent molecules. The thiourea derivative of trianglimine appeared to be a simple, low molecular weight supergelator that formed stable chiral metallogels in N,N-dimethylformamide with Ag(I), Cu(I). and Cu(II) salts. The enantiomeric enrichment of the macrocycle is a necessary condition for effective gelling because neither racemic nor enantiomerically enriched samples (up to 50% ee) form metallogels. The metallogels formed from silver cations and thiourea trianglamine show reversible thixotropic property rarely observed in metallogels.
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Affiliation(s)
- Natalia Prusinowska
- Department of Chemistry, Adam Mickiewicz University , Umultowska 89B, 61 614 Poznan, Poland.,Wielkopolska Center for Advanced Technologies (WCAT) , Umultowska 89C, 61 614 Poznan, Poland
| | - Joanna Szymkowiak
- Department of Chemistry, Adam Mickiewicz University , Umultowska 89B, 61 614 Poznan, Poland.,Wielkopolska Center for Advanced Technologies (WCAT) , Umultowska 89C, 61 614 Poznan, Poland
| | - Marcin Kwit
- Department of Chemistry, Adam Mickiewicz University , Umultowska 89B, 61 614 Poznan, Poland.,Wielkopolska Center for Advanced Technologies (WCAT) , Umultowska 89C, 61 614 Poznan, Poland
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56
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Okesola BO, Smith DK. Applying low-molecular weight supramolecular gelators in an environmental setting - self-assembled gels as smart materials for pollutant removal. Chem Soc Rev 2018; 45:4226-51. [PMID: 27241027 DOI: 10.1039/c6cs00124f] [Citation(s) in RCA: 482] [Impact Index Per Article: 80.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This review explores supramolecular gels as materials for environmental remediation. These soft materials are formed by self-assembling low-molecular-weight building blocks, which can be programmed with molecular-scale information by simple organic synthesis. The resulting gels often have nanoscale 'solid-like' networks which are sample-spanning within a 'liquid-like' solvent phase. There is intimate contact between the solvent and the gel nanostructure, which has a very high effective surface area as a result of its dimensions. As such, these materials have the ability to bring a solid-like phase into contact with liquids in an environmental setting. Such materials can therefore remediate unwanted pollutants from the environment including: immobilisation of oil spills, removal of dyes, extraction of heavy metals or toxic anions, and the detection or removal of chemical weapons. Controlling the interactions between the gel nanofibres and pollutants can lead to selective uptake and extraction. Furthermore, if suitably designed, such materials can be recyclable and environmentally benign, while the responsive and tunable nature of the self-assembled network offers significant advantages over other materials solutions to problems caused by pollution in an environmental setting.
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Affiliation(s)
- Babatunde O Okesola
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
| | - David K Smith
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
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57
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Shapira R, Balazs YS, Kababya S, Edrei R, Eichen Y. Re-entrant supramolecular interactions in inverse-melting α-cyclodextrin·4-methylpyridine·water mixtures: an NMR study. Phys Chem Chem Phys 2018; 20:29610-29615. [DOI: 10.1039/c8cp04328k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Inverse freezing αCD·4MP·H2O turns into a gel as αCD loses its solvation shell. First, it loses its interaction with 4MP, and then its solvation by water.
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Affiliation(s)
- Reut Shapira
- Schulich Faculty of Chemistry
- Technion – Israel Institute of Technology
- Haifa
- Israel
| | - Yael S. Balazs
- Schulich Faculty of Chemistry
- Technion – Israel Institute of Technology
- Haifa
- Israel
| | - Shifi Kababya
- Schulich Faculty of Chemistry
- Technion – Israel Institute of Technology
- Haifa
- Israel
| | - Rachel Edrei
- Schulich Faculty of Chemistry
- Technion – Israel Institute of Technology
- Haifa
- Israel
| | - Yoav Eichen
- Schulich Faculty of Chemistry
- Technion – Israel Institute of Technology
- Haifa
- Israel
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58
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Deamidation of pseudopeptidic molecular hydrogelators and its application to controlled release. J Colloid Interface Sci 2017; 505:1111-1117. [DOI: 10.1016/j.jcis.2017.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 06/26/2017] [Accepted: 07/02/2017] [Indexed: 11/21/2022]
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59
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Vieira VMP, Hay LL, Smith DK. Multi-component hybrid hydrogels - understanding the extent of orthogonal assembly and its impact on controlled release. Chem Sci 2017; 8:6981-6990. [PMID: 29147525 PMCID: PMC5642149 DOI: 10.1039/c7sc03301j] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 08/18/2017] [Indexed: 12/20/2022] Open
Abstract
This paper reports self-assembled multi-component hybrid hydrogels including a range of nanoscale systems and characterizes the extent to which each component maintains its own unique functionality, demonstrating that multi-functionality can be achieved by simply mixing carefully-chosen constituents. Specifically, the individual components are: (i) pH-activated low-molecular-weight gelator (LMWG) 1,3;2,4-dibenzylidenesorbitol-4',4''-dicarboxylic acid (DBS-COOH), (ii) thermally-activated polymer gelator (PG) agarose, (iii) anionic biopolymer heparin, and (iv) cationic self-assembled multivalent (SAMul) micelles capable of binding heparin. The LMWG still self-assembles in the presence of PG agarose, is slightly modified on the nanoscale by heparin, but is totally disrupted by the micelles. However, if the SAMul micelles are bound to heparin, DBS-COOH self-assembly is largely unaffected. The LMWG endows hybrid materials with pH-responsive behavior, while the PG provides mechanical robustness. The rate of heparin release can be controlled through network density and composition, with the LMWG and PG behaving differently in this regard, while the presence of the heparin binder completely inhibits heparin release through complexation. This study demonstrates that a multi-component approach can yield exquisite control over self-assembled materials. We reason that controlling orthogonality in such systems will underpin further development of controlled release systems with biomedical applications.
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Affiliation(s)
- Vânia M P Vieira
- Department of Chemistry , University of York , Heslington , York , YO10 5DD , UK . ; http://www.york.ac.uk/chemistry/staff/academic/o-s/dsmith/
| | - Laura L Hay
- Department of Chemistry , University of York , Heslington , York , YO10 5DD , UK . ; http://www.york.ac.uk/chemistry/staff/academic/o-s/dsmith/
| | - David K Smith
- Department of Chemistry , University of York , Heslington , York , YO10 5DD , UK . ; http://www.york.ac.uk/chemistry/staff/academic/o-s/dsmith/
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60
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Castilla AM, Draper ER, Nolan MC, Brasnett C, Seddon A, Mears LLE, Cowieson N, Adams DJ. Self-sorted Oligophenylvinylene and Perylene Bisimide Hydrogels. Sci Rep 2017; 7:8380. [PMID: 28827598 PMCID: PMC5566499 DOI: 10.1038/s41598-017-08644-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 07/04/2017] [Indexed: 12/31/2022] Open
Abstract
We describe two component hydrogels with networks composed of self-sorted fibres. The component gelators are based on 1,4-distyrylbenzene (OPV3) and perylene bisimide (PBI) units. Self-sorted gels can be formed by a slow decrease in pH, which leads to sequential assembly. We demonstrate self-sorting by NMR, rheology and small angle X-ray scattering (SAXS). Photoconductive xerogels can be prepared by drying these gels. The wavelength response of the xerogel is different to that of the PBI alone.
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Affiliation(s)
- Ana M Castilla
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK
| | - Emily R Draper
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK.,School of Chemistry, WestCHEM, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Michael C Nolan
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK.,School of Chemistry, WestCHEM, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Christopher Brasnett
- School of Physics, HH Wills Physics Laboratory, Tyndall Avenue, University of Bristol, Bristol, BS8 1TL, UK
| | - Annela Seddon
- School of Physics, HH Wills Physics Laboratory, Tyndall Avenue, University of Bristol, Bristol, BS8 1TL, UK.,Bristol Centre for Functional Nanomaterials, HH Wills Physics Laboratory, Tyndall Avenue, University of Bristol, Bristol, BS8 1TL, UK
| | - Laura L E Mears
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK
| | - Nathan Cowieson
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, OX11 0QX, UK
| | - Dave J Adams
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK. .,School of Chemistry, WestCHEM, University of Glasgow, Glasgow, G12 8QQ, UK.
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61
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Xu L, Liang Y, Sun C, Hao N, Yan J, Gao W, He B. Substitution of Percutaneous Ethanol Injection with a Low Molecular Weight Peptide Gel Mimicking Chemoembolization for Cancer Therapy. Nanotheranostics 2017; 1:313-325. [PMID: 29071195 PMCID: PMC5646736 DOI: 10.7150/ntno.20468] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Accepted: 05/27/2017] [Indexed: 02/06/2023] Open
Abstract
In order to avoid the instability and quick separation between emulsifier and drug in the interventional chemoembolization, an injectable low molecular weight peptide gel (LMWG) was prepared to localize ethanol and chemotherapeutic for in situ synergistic therapy. The formation mechanism, rheological property and morphology of the LMWG were investigated by NMR, UV-vis, MS and SEM. The interaction between gelator and anticancer drug doxorubicin hydrochloride (DOX) was evaluated by fluorescence spectroscopy and its contribution on drug loading properties was demonstrated. The gel was non-toxic to both 3T3 fibroblasts and 4T1 breast cancer cells. DOX as well as ethanol were encapsulated in the gel and injected in breast cancer bearing mice with low drug dose (2.5 mg/kg body weight). The LMWG surrounded tumors act as a depot for ethanol release and release DOX to induce the apoptosis of cancer cells. With the combination of percutaneous ethanol injection (PEI) and chemotherapy, the DOX loaded LMWG exhibited great significance in necrosis of tumor tissue and exciting tumor inhibition efficiency.
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Affiliation(s)
- Long Xu
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, China
| | - Yan Liang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, China
| | - Changzheng Sun
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, China
| | - Na Hao
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, China
| | - Jianqin Yan
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, China
| | - Wenxia Gao
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325027, China
| | - Bin He
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, China
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62
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Rajbhandary A, Raymond DM, Nilsson BL. Self-Assembly, Hydrogelation, and Nanotube Formation by Cation-Modified Phenylalanine Derivatives. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:5803-5813. [PMID: 28514156 DOI: 10.1021/acs.langmuir.7b00686] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Fluorenylmethoxycarbonyl-protected phenylalanine (Fmoc-Phe) derivatives are a privileged class of molecule that spontaneously self-assemble into hydrogel fibril networks. Fmoc-Phe-derived hydrogels are typically formed by dilution of the hydrogelator from an organic cosolvent into water, by dissolution of the hydrogelator under basic aqueous conditions followed by adjustment of the pH with acid, or by other external triggering forces, including sonication and heating. These conditions complicate biological applications of these hydrogels. Herein, we report C-terminal cation-modified Fmoc-Phe derivatives that are positively charged across a broad range of pH values and that can self-assemble and form hydrogel networks spontaneously without the need to adjust pH or to use an organic cosolvent. In addition, these cationic Fmoc-Phe derivatives are found to self-assemble into novel sheet-based nanotube structures at higher concentrations. These nanotube structures are unique to C-terminal cationic Fmoc-Phe derivatives; the parent Fmoc-Phe carboxylic acids form only fibril or worm-like micelle structures. Nanotube formation by the cationic Fmoc-Phe molecules is dependent on positive charge at the C-terminus, since at basic pH where the positive charge is reduced only fibrils/worm-like micelles are formed and nanotube formation is suppressed. These studies provide an important example of Fmoc-Phe derivatives that can elicit hydrogelation without organic cosolvent or pH modification and also provide insight into how subtle modification of structure can perturb the self-assembly pathways of Fmoc-Phe derivatives.
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Affiliation(s)
- Annada Rajbhandary
- Department of Chemistry, University of Rochester , Rochester, New York 14627-0216, United States
| | - Danielle M Raymond
- Department of Chemistry, University of Rochester , Rochester, New York 14627-0216, United States
| | - Bradley L Nilsson
- Department of Chemistry, University of Rochester , Rochester, New York 14627-0216, United States
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63
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Ramalhete SM, Nartowski KP, Sarathchandra N, Foster JS, Round AN, Angulo J, Lloyd GO, Khimyak YZ. Supramolecular Amino Acid Based Hydrogels: Probing the Contribution of Additive Molecules using NMR Spectroscopy. Chemistry 2017; 23:8014-8024. [PMID: 28401991 PMCID: PMC5575562 DOI: 10.1002/chem.201700793] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Indexed: 11/08/2022]
Abstract
Supramolecular hydrogels are composed of self-assembled solid networks that restrict the flow of water. l-Phenylalanine is the smallest molecule reported to date to form gel networks in water, and it is of particular interest due to its crystalline gel state. Single and multi-component hydrogels of l-phenylalanine are used herein as model materials to develop an NMR-based analytical approach to gain insight into the mechanisms of supramolecular gelation. Structure and composition of the gel fibres were probed using PXRD, solid-state NMR experiments and microscopic techniques. Solution-state NMR studies probed the properties of free gelator molecules in an equilibrium with bound molecules. The dynamics of exchange at the gel/solution interfaces was investigated further using high-resolution magic angle spinning (HR-MAS) and saturation transfer difference (STD) NMR experiments. This approach allowed the identification of which additive molecules contributed in modifying the material properties.
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Affiliation(s)
| | - Karol P. Nartowski
- School of PharmacyUniversity of East AngliaNorwich Research ParkNR4 7TJUK
- Current address: Department of Drug Form TechnologyFaculty of PharmacyWroclaw Medical Universityul. Borowska 21150-556WroclawPoland
| | | | - Jamie S. Foster
- Institute of Chemical Sciences, School of Engineering and Physical SciencesHeriot-Watt UniversityEH14 4ASUK
| | - Andrew N. Round
- School of PharmacyUniversity of East AngliaNorwich Research ParkNR4 7TJUK
| | - Jesús Angulo
- School of PharmacyUniversity of East AngliaNorwich Research ParkNR4 7TJUK
| | - Gareth O. Lloyd
- Institute of Chemical Sciences, School of Engineering and Physical SciencesHeriot-Watt UniversityEH14 4ASUK
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64
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Rajbhandary A, Nilsson BL. Investigating the effects of peptoid substitutions in self-assembly of Fmoc-diphenylalanine derivatives. Biopolymers 2017; 108. [PMID: 27696352 DOI: 10.1002/bip.22994] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 09/22/2016] [Indexed: 12/24/2022]
Abstract
Low molecular weight agents that undergo self-assembly into fibril networks with hydrogel properties are promising biomaterials. Most low molecular weight hydrogelators are discovered empirically or serendipitously due to imperfect understanding of the mechanisms of self-assembly, the packing structure of self-assembled materials, and how the self-assembly process corresponds to emergent hydrogelation. Herein, the mechanisms of self-assembly and hydrogelation of N-fluorenylmethoxycarbonyl diphenylalanine (Fmoc-PhePhe), a well-studied low molecular weight hydrogelator, is probed by systematic comparison with derivatives in which Phe residues are replaced by corresponding N-benzyl glycine peptoid (Nphe) analogs. Peptoids are peptidomimetics that shift display of side chain functionality from the α-carbon to the terminal nitrogen. This alters the hydrogen bonding capacity, the side chain presentation geometry, amide cis/trans isomerization equilibrium, and β-sheet potential of the peptoid relative to the corresponding amino acid in the context of peptidic polymers. It was found that amino acid/peptoid hybrids Fmoc-Phe-Nphe and Fmoc-Nphe-Phe have altered fibril self-assembly propensity and reduced hydrogelation capacity relative to the parent dipeptide, and that fibril self-assembly of the dipeptoid, Fmoc-Nphe-Nphe, is completely curtailed. These findings provide insight into the potential of low molecular weight peptoids and peptide/peptoid hybrids as hydrogelation agents and illuminate the importance of hydrogen bonding and π-π interaction geometry in facilitating self-assembly of Fmoc-Phe-Phe.
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Affiliation(s)
| | - Bradley L Nilsson
- Department of Chemistry, University of Rochester, Rochester, New York
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65
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Lin P, Zhang NX, Li JJ, Zhang J, Liu JH, Zhang B, Song J. To gel or not to gel: A prior prediction of gelation in solvent mixtures. CHINESE CHEM LETT 2017. [DOI: 10.1016/j.cclet.2016.12.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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66
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Tatikonda R, Bertula K, Nonappa, Hietala S, Rissanen K, Haukka M. Bipyridine based metallogels: an unprecedented difference in photochemical and chemical reduction in the in situ nanoparticle formation. Dalton Trans 2017; 46:2793-2802. [PMID: 28174774 PMCID: PMC5777448 DOI: 10.1039/c6dt04253h] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 02/02/2017] [Indexed: 12/19/2022]
Abstract
Metal co-ordination induced supramolecular gelation of low molecular weight organic ligands is a rapidly expanding area of research due to the potential in creating hierarchically self-assembled multi-stimuli responsive materials. In this context, structurally simple O-methylpyridine derivatives of 4,4'-dihydroxy-2,2'-bipyridine ligands are reported. Upon complexation with Ag(i) ions in aqueous dimethyl sulfoxide (DMSO) solutions the ligands spontaneously form metallosupramolecular gels at concentrations as low as 0.6 w/v%. The metal ions induce the self-assembly of three dimensional (3D) fibrillar networks followed by the spontaneous in situ reduction of the Ag-centers to silver nanoparticles (AgNPs) when exposed to daylight. Significant size and morphological differences of the AgNP's was observed between the standard chemical and photochemical reduction of the metallogels. The gelation ability, the nanoparticle formation and rheological properties were found to be depend on the ligand structure, while the strength of the gels is affected by the water content of the gels.
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Affiliation(s)
- Rajendhraprasad Tatikonda
- Department of Chemistry, Nanoscience Center, University of Jyväskylä, P. O. Box 35, FI-40014, Jyväskylä, Finland.
| | - Kia Bertula
- Department of Applied Physics, Molecular Materials Group, Aalto University School of Science, Puumiehenkuja 2, FI-02150, Espoo, Finland
| | - Nonappa
- Department of Applied Physics, Molecular Materials Group, Aalto University School of Science, Puumiehenkuja 2, FI-02150, Espoo, Finland
| | - Sami Hietala
- Department of Chemistry, University of Helsinki, P. O. Box 55, FI-00014, Helsinki, Finland
| | - Kari Rissanen
- Department of Chemistry, Nanoscience Center, University of Jyväskylä, P. O. Box 35, FI-40014, Jyväskylä, Finland.
| | - Matti Haukka
- Department of Chemistry, Nanoscience Center, University of Jyväskylä, P. O. Box 35, FI-40014, Jyväskylä, Finland.
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67
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Wallace M, Iggo JA, Adams DJ. Probing the surface chemistry of self-assembled peptide hydrogels using solution-state NMR spectroscopy. SOFT MATTER 2017; 13:1716-1727. [PMID: 28165092 DOI: 10.1039/c6sm02404a] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The surface chemistry of self-assembled hydrogel fibres - their charge, hydrophobicity and ion-binding dynamics - is recognised to play an important role in determining how the gels develop as well as their suitability for different applications. However, to date there are no established methodologies for the study of this surface chemistry. Here, we demonstrate how solution-state NMR spectroscopy can be employed to measure the surface chemical properties of the fibres in a range of hydrogels formed from N-functionalised dipeptides, an effective and versatile class of gelator that has attracted much attention. By studying the interactions with the gel fibres of a diverse range of probe molecules and ions, we can simultaneously study a number of surface chemical properties of the NMR invisible fibres in an essentially non-invasive manner. Our results yield fresh insights into the materials. Most notably, gel fibres assembled using different tiggering methods bear differing amounts of negative charge as a result of a partial deprotonation of the carboxylic acid groups of the gelators. We also demonstrate how chemical shift imaging (CSI) techniques can be applied to follow the formation of hydrogels along chemical gradients. We apply CSI to study the binding of Ca2+ and subsequent gelation of peptide assemblies at alkaline pH. Using metal ion-binding molecules as probes, we are able to detect the presence of bound Ca2+ ions on the surface of the gel fibres. We briefly explore how knowledge of the surface chemical properties of hydrogels could be used to inform their practical application in fields such as drug delivery and environmental remediation.
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Affiliation(s)
- Matthew Wallace
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK.
| | - Jonathan A Iggo
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK.
| | - Dave J Adams
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK.
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68
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How do H-bonding interactions control viscoelasticity and thixotropy of molecular gels? Insights from mono-, di- and tri-hydroxymethylated alkanamide gelators. J Colloid Interface Sci 2017; 486:359-371. [DOI: 10.1016/j.jcis.2016.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 10/03/2016] [Accepted: 10/04/2016] [Indexed: 12/17/2022]
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69
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Arnedo-Sánchez L, Nonappa N, Bhowmik S, Hietala S, Puttreddy R, Lahtinen M, De Cola L, Rissanen K. Rapid self-healing and anion selectivity in metallosupramolecular gels assisted by fluorine–fluorine interactions. Dalton Trans 2017; 46:7309-7316. [DOI: 10.1039/c7dt00983f] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Metal complexes from perfluoroalkylamide terpyridine self-assemble into anion selective gels, which manifest self-healing and thermal rearrangement in aqueous dimethyl sulfoxide.
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Affiliation(s)
| | - Nonappa Nonappa
- Molecular Materials Group
- Department of Applied Physics
- Aalto University School of Science
- Espoo
- Finland
| | - Sandip Bhowmik
- University of Jyvaskyla
- Department of Chemistry
- Nanoscience Center
- Jyväskylä
- Finland
| | - Sami Hietala
- Department of Chemistry
- University of Helsinki
- Helsinki
- Finland
| | - Rakesh Puttreddy
- University of Jyvaskyla
- Department of Chemistry
- Nanoscience Center
- Jyväskylä
- Finland
| | - Manu Lahtinen
- University of Jyvaskyla
- Department of Chemistry
- Nanoscience Center
- Jyväskylä
- Finland
| | - Luisa De Cola
- ISIS
- Université de Strasbourg and CNRS UMR 7006
- Strasbourg 67000
- France
| | - Kari Rissanen
- University of Jyvaskyla
- Department of Chemistry
- Nanoscience Center
- Jyväskylä
- Finland
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70
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Castilla AM, Wallace M, Mears LLE, Draper ER, Doutch J, Rogers S, Adams DJ. On the syneresis of an OPV functionalised dipeptide hydrogel. SOFT MATTER 2016; 12:7848-7854. [PMID: 27714311 DOI: 10.1039/c6sm01194b] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We describe a new dipeptide hydrogel based on an oligophenylene vinylene core. After gelation, the initial network evolves, expelling solvent and resulting in syneresis. We describe this process and the effects in the bulk properties of the material.
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Affiliation(s)
- Ana M Castilla
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK.
| | - Matthew Wallace
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK.
| | - Laura L E Mears
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK.
| | - Emily R Draper
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK.
| | - James Doutch
- ISIS Pulsed Neutron Source, Rutherford Appleton Laboratory, Didcot, UK
| | - Sarah Rogers
- ISIS Pulsed Neutron Source, Rutherford Appleton Laboratory, Didcot, UK
| | - Dave J Adams
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK.
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71
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Boekhoven J, Brizard AM, Stuart MCA, Florusse L, Raffy G, Del Guerzo A, van Esch JH. Bio-inspired supramolecular materials by orthogonal self-assembly of hydrogelators and phospholipids. Chem Sci 2016; 7:6021-6031. [PMID: 30034743 PMCID: PMC6022170 DOI: 10.1039/c6sc01021k] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 05/06/2016] [Indexed: 12/12/2022] Open
Abstract
The orthogonal self-assembly of multiple components is a powerful strategy towards the formation of complex biomimetic architectures, but so far the rules for designing such systems are unclear. Here we show how to identify orthogonal self-assembly at the supramolecular level and describe guidelines to achieve self-sorting in self-assembled mixed systems. By investigating multicomponent self-assembled systems consisting of low molecular weight gelators and phospholipids, both at a molecular and a supramolecular level, we found that orthogonal self-assembly can only take place if the entities assemble via a strong and distinct set of interactions. The resulting supramolecular architectures consist of fibrillar networks that coexist with liposomes and thereby provide additional levels of compartmentalization and enhanced stability as compared to self-assembled systems of gelators or phospholipids alone.
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Affiliation(s)
- J Boekhoven
- Department of Chemical Engineering , Delft University of Technology , Julianalaan 136 , 2628BL Delft , The Netherlands .
| | - A M Brizard
- Department of Chemical Engineering , Delft University of Technology , Julianalaan 136 , 2628BL Delft , The Netherlands .
| | - M C A Stuart
- Stratingh Institute for Chemistry , University of Groningen , Nijenborgh 7 , 9747AG Groningen , The Netherlands
| | - L Florusse
- Department of Chemical Engineering , Delft University of Technology , Julianalaan 136 , 2628BL Delft , The Netherlands .
| | - G Raffy
- Univ. Bordeaux , ISM , UMR 5255 , 351 cours de la Libération , 33400 Talence , France
| | - A Del Guerzo
- Univ. Bordeaux , ISM , UMR 5255 , 351 cours de la Libération , 33400 Talence , France
| | - J H van Esch
- Department of Chemical Engineering , Delft University of Technology , Julianalaan 136 , 2628BL Delft , The Netherlands .
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72
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Nonappa, Kolehmainen E. Solid state NMR studies of gels derived from low molecular mass gelators. SOFT MATTER 2016; 12:6015-26. [PMID: 27374054 PMCID: PMC5322468 DOI: 10.1039/c6sm00969g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 06/16/2016] [Indexed: 06/06/2023]
Abstract
Since its invention more than six decades ago, nuclear magnetic resonance (NMR) spectroscopy has evolved as an inevitable part of chemical as well as structural analysis of small molecules, polymers, biomaterials and hybrid materials. In the solution state, due to the increased viscosity of complex viscoelastic fluids such as gels, liquid crystals and other soft materials, the rate of molecular tumbling is reduced, which in turn affects the chemical shift anisotropy, dipolar and quadrupolar interactions. As a consequence the solution state NMR spectra show broad lines, and therefore, extracting detailed structural information is a challenging task. In this context, solid state (SS) NMR has the ability to distinguish between a minute amount of polymorphic forms, conformational changes, and the number of non-equivalent molecules in an asymmetric unit of a crystal lattice, and to provide both qualitative as well as quantitative analytical data with a short-range order. Therefore, SS NMR has continued to evolve as an indispensable tool for structural analysis and gave birth to a new field called NMR crystallography. Solid state cross polarization (CP) and high resolution (HR) magic angle spinning (MAS) NMR spectroscopy has been used to study weak interactions in polymer gels. However, the application of SS NMR spectroscopy to study gels derived from low molecular weight gelators has been limited until recently. In this review, we will focus on the importance of solid state NMR spectroscopy in understanding and elucidating the structure of supramolecular gels derived from low molecular weight gelators with selected examples.
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Affiliation(s)
- Nonappa
- Department of Applied Physics, Aalto University School of Science, Puumiehenkuja 2, Espoo, FI-02150, Finland.
| | - E Kolehmainen
- Department of Chemistry, University of Jyväskylä, Jyväskylä, FI-41004, Finland.
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73
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Baker BC, Higgins CL, Ravishankar D, Colquhoun HM, Stevens GC, Greco F, Greenland BW, Hayes W. Multifunctional, Biocompatible, Non-peptidic Hydrogels: from Water Purification to Drug Delivery. ChemistrySelect 2016. [DOI: 10.1002/slct.201600249] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Benjamin C. Baker
- Department of Chemistry; University of Reading; Whiteknights, Reading RG6 6AD UK
| | - Clare L. Higgins
- Department of Chemistry; University of Reading; Whiteknights, Reading RG6 6AD UK
| | | | - Howard M. Colquhoun
- Department of Chemistry; University of Reading; Whiteknights, Reading RG6 6AD UK
| | - Gary C. Stevens
- Gnosys Global Ltd.; 17-18 Frederick Sanger Road Guildford, Surrey GU2 7YD UK
| | - Francesca Greco
- School of Pharmacy; University of Reading; Whiteknights, Reading RG6 6AP UK
| | | | - Wayne Hayes
- Department of Chemistry; University of Reading; Whiteknights, Reading RG6 6AD UK
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74
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Angulo-Pachón CA, Gascó-Catalán C, Ojeda-Flores JJ, Miravet JF. Improved Efficiency of Molecular-Gel Formation by Adjusting Preorganization of Amino-Acid-Derived Flexible Molecules: A NMR and Thermodynamic study. Chemphyschem 2016; 17:2008-12. [DOI: 10.1002/cphc.201600015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/10/2016] [Indexed: 11/11/2022]
Affiliation(s)
- César A. Angulo-Pachón
- Departament de Química Inorgànica i Orgànica; Universitat Jaume I; Avda. Sos Baynat s/n 12071 Castellón Spain
| | - Carolina Gascó-Catalán
- Departament de Química Inorgànica i Orgànica; Universitat Jaume I; Avda. Sos Baynat s/n 12071 Castellón Spain
| | - Juan J. Ojeda-Flores
- Departament de Química Inorgànica i Orgànica; Universitat Jaume I; Avda. Sos Baynat s/n 12071 Castellón Spain
| | - Juan F. Miravet
- Departament de Química Inorgànica i Orgànica; Universitat Jaume I; Avda. Sos Baynat s/n 12071 Castellón Spain
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75
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Zhang C, Zhang T, Ji N, Zhang Y, Bai B, Wang H, Li M. Gelation behaviour of a bent-core dihydrazide derivative: effect of incubation temperature in chloroform and toluene. SOFT MATTER 2016; 12:1525-1533. [PMID: 26659559 DOI: 10.1039/c5sm02535d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this work, a new kind of gelator, 1,3-bis[(3,4-dioctyloxy phenyl) hydrazide]phenylene (BP8-C), containing two dihydrazide units as the rigid bent-core, has been synthesized and investigated. It was demonstrated that BP8-C is an efficient gelator which can gel various organic solvents, such as ethanol, benzene, toluene, chloroform, etc. Both an opaque gel (O-gel) and a transparent gel (T-gel), which is more stable, were obtained with BP8-C in chloroform at different incubation temperatures. Kinetic data based on fluorescence spectra revealed that the T-gels showed a larger Avrami parameter (n = 1.44 at 20 °C) than that of the O-gels (n = 1.21 for gelation at temperatures below 0 °C). While BP8-C did form the opaque gel in toluene, gelation took longer at lower incubation temperatures and even precipitated out below 0 °C. The kinetic Avrami analysis on sols of BP8-C with different concentrations shows a two-phrase mechanism, i.e. the n values are between 0.88 and 1.74 followed by 1.69 and 3.01 throughout the temperature range of 5 °C and 35 °C for 5.34 mg mL(-1) BP8-C in toluene, indicating that the fibers formed first and then bundled to produce compact networks. We propose that supersaturation governs the formation of gel in chloroform and that the diffusion process denominates gelation in toluene. XRD and FT-IR measurements confirmed that the xerogels prepared at different temperatures in different solvents exhibited a Col(h) structure and that there are three molecules in one columnar slice. Our results indicate that the gelation process, morphology of the gels and thus the final properties of the gels depend strongly on the preparation conditions such as temperature, solvent, concentration, etc.
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Affiliation(s)
- Chunxue Zhang
- Key Laboratory of Automobile Materials, Ministry of Education, Institute of Materials Science and Engineering, Jilin University, Changchun 130012, People's Republic of China.
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76
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Portada T, Molčanov K, Šijaković Vujičić N, Žinić M. Biphenyl Bis(amino alcohol) Oxalamide Gelators: Complex Gelation Involving Coupled Equilibria, Central-to-Axial Chirality Transfer, Diastereoisomer Interconversion, and Self-Sorting. European J Org Chem 2016. [DOI: 10.1002/ejoc.201501261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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77
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Jia XJ, Wang J, Zhong DC, Wu J, Zhao B, Engelsen DD, Luo XZ. A thermo-sensitive supramolecular hydrogel derived from an onium salt with solution–gel–crystal transition properties. RSC Adv 2016. [DOI: 10.1039/c6ra23761d] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A self-assembled supramolecular hydrogel, which not only exhibits thermo-sensitive characteristics but has the property of solution–gel–crystal transition, is obtained by mixing the aqueous solutions of benzoic acid and melamine.
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Affiliation(s)
- Xin-Jian Jia
- Key Laboratory of Advanced Functional Materials for Ministry of Education
- College of Materials Science and Engineering
- Beijing University of Technology
- Beijing 100124
- China
| | - Jinshu Wang
- Key Laboratory of Advanced Functional Materials for Ministry of Education
- College of Materials Science and Engineering
- Beijing University of Technology
- Beijing 100124
- China
| | - Di-Chang Zhong
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province
- Key Laboratory of Jiangxi University for Functional Material Chemistry
- Gannan Normal University
- Ganzhou 341000
- China
| | - Junshu Wu
- Key Laboratory of Advanced Functional Materials for Ministry of Education
- College of Materials Science and Engineering
- Beijing University of Technology
- Beijing 100124
- China
| | - Bingxin Zhao
- Key Laboratory of Advanced Functional Materials for Ministry of Education
- College of Materials Science and Engineering
- Beijing University of Technology
- Beijing 100124
- China
| | - Daniel den Engelsen
- Key Laboratory of Advanced Functional Materials for Ministry of Education
- College of Materials Science and Engineering
- Beijing University of Technology
- Beijing 100124
- China
| | - Xu-Zhong Luo
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province
- Key Laboratory of Jiangxi University for Functional Material Chemistry
- Gannan Normal University
- Ganzhou 341000
- China
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78
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Conejero-Muriel M, Gavira JA, Pineda-Molina E, Belsom A, Bradley M, Moral M, García-López Durán JDD, Luque González A, Díaz-Mochón JJ, Contreras-Montoya R, Martínez-Peragón Á, Cuerva JM, Álvarez de Cienfuegos L. Influence of the chirality of short peptide supramolecular hydrogels in protein crystallogenesis. Chem Commun (Camb) 2015; 51:3862-5. [PMID: 25655841 DOI: 10.1039/c4cc09024a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
For the first time the influence of the chirality of the gel fibers in protein crystallogenesis has been studied. Enantiomeric hydrogels 1 and 2 were tested with model proteins lysozyme and glucose isomerase and a formamidase extracted from B. cereus. Crystallization behaviour and crystal quality of these proteins in both hydrogels are presented and compared.
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Affiliation(s)
- Mayte Conejero-Muriel
- Laboratorio de Estudios Cristalográficos, Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR), Av. de las Palmeras 4, 18100 Armilla, Granada, Spain.
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79
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Wallace M, Iggo JA, Adams DJ. Using solution state NMR spectroscopy to probe NMR invisible gelators. SOFT MATTER 2015; 11:7739-47. [PMID: 26313637 DOI: 10.1039/c5sm01760b] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Supramolecular hydrogels are formed via the self-assembly of gelator molecules upon application of a suitable trigger. The exact nature of this self-assembly process has been widely investigated as a practical understanding is vital for the informed design of these materials. Solution-state NMR spectroscopy is an excellent non-invasive tool to follow the self-assembly of supramolecular hydrogels. However, in most cases the self-assembled aggregates are silent by conventional (1)H NMR spectroscopy due to the low mobility of the constituent molecules, limiting NMR spectroscopy to following only the initial assembly step(s). Here, we present a new solution-state NMR spectroscopic method which allows the entire self-assembly process of a dipeptide gelator to be followed. This gelator forms transparent hydrogels by a multi-stage assembly process when the pH of an initially alkaline solution is lowered via the hydrolysis of glucono-δ-lactone (GdL). Changes in the charge, hydrophobicity and relative arrangement of the supramolecular aggregates can be followed throughout the assembly process by measuring the residual quadrupolar couplings (RQCs) of various molecular probes (here, (14)NH4(+) and isopropanol-d8), along with the NMR relaxation rates of (23)Na(+). The initially-formed aggregates comprise negatively charged fibrils which gradually lose their charge and become increasingly hydrophobic as the pH falls, eventually resulting in a macroscopic contraction of the hydrogel. We also demonstrate that the in situ measurement of pH by NMR spectroscopy is both convenient and accurate, representing a useful tool for the characterisation of self-assembly processes by NMR.
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Affiliation(s)
- Matthew Wallace
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK.
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80
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Yamagishi H, Fukino T, Hashizume D, Mori T, Inoue Y, Hikima T, Takata M, Aida T. Metal–Organic Nanotube with Helical and Propeller-Chiral Motifs Composed of a C10-Symmetric Double-Decker Nanoring. J Am Chem Soc 2015; 137:7628-31. [DOI: 10.1021/jacs.5b04386] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hiroshi Yamagishi
- Department
of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Takahiro Fukino
- Department
of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Daisuke Hashizume
- RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Tadashi Mori
- Department
of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1
Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Yoshihisa Inoue
- Department
of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1
Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Takaaki Hikima
- RIKEN SPring-8 Center, 1-1-1
Kouto, Sayo, Hyogo 679-5198, Japan
| | - Masaki Takata
- RIKEN SPring-8 Center, 1-1-1
Kouto, Sayo, Hyogo 679-5198, Japan
| | - Takuzo Aida
- Department
of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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81
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Wei SC, Pan M, Fan YZ, Liu H, Zhang J, Su CY. Creating Coordination-Based Cavities in a Multiresponsive Supramolecular Gel. Chemistry 2015; 21:7418-27. [DOI: 10.1002/chem.201406517] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Indexed: 12/21/2022]
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82
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Šaman D, Kolehmainen E. Studies on supramolecular gel formation using DOSY NMR. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2015; 53:256-260. [PMID: 25631685 DOI: 10.1002/mrc.4185] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Revised: 10/15/2014] [Accepted: 10/17/2014] [Indexed: 06/04/2023]
Abstract
Herein, we present the results obtained from our studies on supramolecular self-assembly and molecular mobility of low-molecular-weight gelators (LMWGs) in organic solvents using pulsed field gradient (PFG) diffusion ordered spectroscopy (DOSY) NMR. A series of concentration-dependent DOSY NMR experiments were performed on selected LMWGs to determine the critical gelation concentration (CGC) as well as to understand the behaviour of the gelator molecules in the gel state. In addition, variable-temperature DOSY NMR experiments were performed to determine the gel-to-sol transition. The PFG NMR experiments performed as a function of gradient strength were further analyzed using monoexponential DOSY processing, and the results were compared with the automated Bayesian DOSY transformation to obtain 2D plots. Our results provide useful information on the stepwise self-assembly of small molecules leading to gelation. We believe that the results obtained from these experiments are applicable in determining the CGC and gel melting temperatures of supramolecular gels.
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83
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Moussodia RO, Acherar S, Romero E, Didierjean C, Jamart-Grégoire B. Evidence of Nanotubular Self-Organization in Solution and Solid States of Heterochiral Cyclo 1:1 [α/α-Nα-Bn-hydrazino]mers Series. J Org Chem 2015; 80:3022-9. [DOI: 10.1021/jo502684g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Ralph-Olivier Moussodia
- Laboratoire
de Chimie Physique Macromoléculaire (LCPM), Université de Lorraine-CNRS, UMR 7375, 1 rue Grandville, BP 20451, 54001 Nancy cedex, France
| | - Samir Acherar
- Laboratoire
de Chimie Physique Macromoléculaire (LCPM), Université de Lorraine-CNRS, UMR 7375, 1 rue Grandville, BP 20451, 54001 Nancy cedex, France
| | - Eugénie Romero
- Laboratoire
de Chimie Physique Macromoléculaire (LCPM), Université de Lorraine-CNRS, UMR 7375, 1 rue Grandville, BP 20451, 54001 Nancy cedex, France
| | - Claude Didierjean
- Laboratoire de Crystallographie, Résonance Magnétique
et Modélisations (CRM2), Université de Lorraine-CNRS, UMR 7036, Faculté des Sciences et Technologies, BP 20239, 54506 Vandœuvre-lès-Nancy cedex, France
| | - Brigitte Jamart-Grégoire
- Laboratoire
de Chimie Physique Macromoléculaire (LCPM), Université de Lorraine-CNRS, UMR 7375, 1 rue Grandville, BP 20451, 54001 Nancy cedex, France
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84
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Abstract
We discuss the potential and challenges of multicomponent low molecular weight gels.
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Affiliation(s)
- Jaclyn Raeburn
- Department of Chemistry
- University of Liverpool
- Liverpool
- UK
| | - Dave J. Adams
- Department of Chemistry
- University of Liverpool
- Liverpool
- UK
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85
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Rohner SS, Ruiz-Olles J, Smith DK. Speed versus stability – structure–activity effects on the assembly of two-component gels. RSC Adv 2015. [DOI: 10.1039/c5ra01256b] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Modifying the peripheral peptides dramatically changes the time required for gelation under ambient conditions, whilst an enthalpy–entropy balance means that as the temperature increases, the thermal stability of the gels is very similar.
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86
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Geiger HC, Lamson M, Galka DJ. Synthesis and spectroscopic characterization of chiral biphenyl-cholesterol gels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:13979-13986. [PMID: 25350932 DOI: 10.1021/la503954b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The synthesis of 4-(3-cholesteroxycarbonylpropyloxy)biphenyl (BO4-chol), 4-(7-cholesteroxycarbonylheptyloxy)biphenyl (BO8-chol), and 4,4'-bis(7-cholesteroxycarbonyl heptyloxy)biphenyl (BBO8-chol) is reported. These gelators form 1% and 2% (w/w) stable gels in n-octanol. The gels formed from single cholesterol gelators (BO4-chol and BO8-chol) exhibit lower phase transition temperatures (Tg) (62-65, 68-69 °C) than the gel obtained from the bischolesterol gelator BBO8-chol (96-98 °C). All three gelators form chiral gels in n-octanol as observed by induced circular dichroism (ICD) spectroscopy. The effect of two cholesterol moieties versus one cholesterol unit linked to a biphenyl molecule by a flexible chain, and the effect of the chain length on the gelation ability of these three novel gelators was investigated by circular dichroism (CD), absorption, and fluorescence spectroscopies. The gels obtained from BO4-chol and BO8-chol exhibit biphasic circular dichroism spectra with opposite chirality. The ICD spectra of both BO8-chol and BBO8-chol gels show a positive ICD band followed by a negative band at room temperature. However, while BO8-chol gel ICD absorptions decrease equally as temperature increases, BBO8-chol gel shows an inversion of the Cotton effect bands between 50 and 60 °C until completely disappearing above the phase transition temperature. SEM was used for the investigation of the morphology of the xerogels. On the basis of XRD data and molecular modeling, we propose packing modes for the formation of the organogelator aggregates.
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Affiliation(s)
- H Cristina Geiger
- Department of Chemistry, State University of New York College at Geneseo , Geneseo, New York 14454, United States
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87
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Baker B, Acton A, Stevens G, Hayes W. Bis amide-aromatic-ureas—highly effective hydro- and organogelator systems. Tetrahedron 2014. [DOI: 10.1016/j.tet.2014.09.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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88
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Yu Q, Fan M, Li D, Song Z, Cai M, Zhou F, Liu W. Thermoreversible gel lubricants through universal supramolecular assembly of a nonionic surfactant in a variety of base lubricating liquids. ACS APPLIED MATERIALS & INTERFACES 2014; 6:15783-15794. [PMID: 25111146 DOI: 10.1021/am502832z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The present paper investigates a new type of thermoreversible gel lubricant obtained by supramolecular assembly of low-molecular-weight organic gelator (LMWG) in different base oils. The LMWG is a nonionic surfactant with polar headgroup and hydrophobic tail that can self-assemble through collective noncovalent intermolecular interactions (H-bonding, hydrophobic interaction) to form fibrous structures and trap base oils (mineral oils, synthetic oils, and water) in the as-formed cavities. The gel lubricants are fully thermoreversible upon heating-up and cooling down and exhibit thixotropic characteristics. This makes them semisolid lubricants, but they behave like oils. The tribological test results disclosed that the LMWG could also effectively reduce friction and wear of sliding pairs compared with base oils without gelator. It is expected that when being used in oil-lubricated components, such as gear, rolling bearing, and so on, gel lubricant may effectively avoid base oil leak and evaporation loss and so is a benefit to operation and lubrication failure for a long time.
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Affiliation(s)
- Qiangliang Yu
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000, China
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89
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Cornwell DJ, Okesola BO, Smith DK. Multidomain Hybrid Hydrogels: Spatially Resolved Photopatterned Synthetic Nanomaterials Combining Polymer and Low-Molecular-Weight Gelators. Angew Chem Int Ed Engl 2014; 53:12461-5. [DOI: 10.1002/anie.201405098] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 07/08/2014] [Indexed: 11/08/2022]
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90
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Cornwell DJ, Okesola BO, Smith DK. Multidomain Hybrid Hydrogels: Spatially Resolved Photopatterned Synthetic Nanomaterials Combining Polymer and Low-Molecular-Weight Gelators. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201405098] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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91
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Shen H, Niu L, Fan K, Li J, Guan X, Song J. Application of solubility parameters in 1,3:2,4-bis(3,4-dimethylbenzylidene)sorbitol organogel in binary organic mixtures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:9176-9182. [PMID: 25019199 DOI: 10.1021/la5019532] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The gelation behavior of 1,3:2,4-bis(3,4-dimethylbenzylidene)sorbitol (DMDBS) in binary solvents has been systematically investigated. DMDBS is soluble in DMSO and insoluble in toluene (apolar) or 1-propanol (polar). When DMSO is added to a poor solvent at a certain volume fraction, DMDBS forms an organogel in the mixed solvent. With increasing DMSO content, the minimum gelation concentration increases and the gel-to-sol transition temperature decreases in both systems. However, compared with those in toluene-DMSO mixtures, the gelation ability and thermal stability are better in 1-propanol-DMSO mixtures. Scanning electron microscopy images reveal that the gelators aggregate to form three-dimensional networks. X-ray diffraction shows that the gel has a lamellar structure, which is different from the structure of the precipitate. Fourier transform infrared results reveal H-bonding is the main driving force for self-aggregation and indicate that stronger H-bonding interactions exist between gelators in 1-propanol-DMSO mixtures in contrast with toluene-DMSO mixtures. Attempts have been taken to correlate solvent parameters to gelation behavior in binary solvents. A Teas plot exhibits distinctly different solvent zones in the studied mixed solvents. The polar parameter (δp) indicates a narrow favorable domain for gel formation in the range of 1.64-7.99 MPa(1/2) for some apolar solvent-DMSO mixtures. The hydrogen-bonding parameter (δh) predicts that gelation occurs for values of 14.00-16.50 MPa(1/2) for some polar solvent-DMSO mixtures. The result may have potential applications in predicting the gelation behavior of 1,3:2,4-di-O-benzylidene-d-sorbitol derivatives in mixed solvents.
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Affiliation(s)
- Huahua Shen
- School of Chemical Engineering and Technology, Tianjin University , Tianjin 300072, China
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92
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Way AE, Korpusik AB, Dorsey TB, Buerkle LE, von Recum HA, Rowan SJ. Enhancing the Mechanical Properties of Guanosine-Based Supramolecular Hydrogels with Guanosine-Containing Polymers. Macromolecules 2014. [DOI: 10.1021/ma402618z] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Amanda E. Way
- Department
of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106, United States
| | - Angie B. Korpusik
- Department
of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106, United States
- Department
of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Taylor B. Dorsey
- Department
of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Lauren E. Buerkle
- Department
of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106, United States
| | - Horst A. von Recum
- Department
of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106, United States
- Department
of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Stuart J. Rowan
- Department
of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106, United States
- Department
of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States
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93
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Skilling KJ, Citossi F, Bradshaw TD, Ashford M, Kellam B, Marlow M. Insights into low molecular mass organic gelators: a focus on drug delivery and tissue engineering applications. SOFT MATTER 2014; 10:237-56. [PMID: 24651822 DOI: 10.1039/c3sm52244j] [Citation(s) in RCA: 254] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
In recent years low molecular mass organic gelators (LMOGs) have gained increasing interest as an alternative biomaterial to polymer derived gels, with potential applications in drug delivery and tissue engineering. LMOGs are small organic molecules which self-assemble in water or organic solvents forming a 3D network that entraps the liquid phase resulting in gel formation. In this review, we report the classification of LMOGs into hydrogelators and gelators of organic solvents and we discuss the techniques commonly used to characterise the gels of these gelators with particular reference to specific applications of LMOGs in drug delivery and tissue engineering.
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Affiliation(s)
- Kathryn J Skilling
- School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
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94
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Edwards W, Smith DK. Enantioselective Component Selection in Multicomponent Supramolecular Gels. J Am Chem Soc 2014; 136:1116-24. [DOI: 10.1021/ja411724r] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- William Edwards
- Department of Chemistry, University of York, Heslington, York, YO10
5DD, U.K
| | - David K. Smith
- Department of Chemistry, University of York, Heslington, York, YO10
5DD, U.K
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95
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Fontanillo M, Angulo-Pachón CA, Escuder B, Miravet JF. In situ synthesis-gelation at room temperature vs. heating-cooling procedure. Fine tuning of molecular gels derived from succinic acid and L-valine. J Colloid Interface Sci 2013; 412:65-71. [PMID: 24144375 DOI: 10.1016/j.jcis.2013.08.055] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 08/30/2013] [Indexed: 10/26/2022]
Abstract
HYPOTHESIS The reaction between succinic anhydride and a diamine derived from L-valine should afford efficiently a molecular gelator. Based on this reaction, it should be feasible to prepare molecular gels at room temperature, avoiding the conventional thermal treatment required for the solubilization of the gelator, by in situ, simultaneous, synthesis and gelation. The gels prepared by in situ and conventional heating-cooling protocols could present important differences relevant for potential practical applications of these materials. EXPERIMENTAL The gelator was synthesized by reaction of succinic anhydride and a diamine derived from L-valine, affording two new amide bonds. The molecular gels were studied by IR, NMR, electron microscopy, X-ray diffraction and DSC. FINDINGS The results indicate that different polymorphic fibrillar networks are formed depending on the gel preparation method, highlighting how the properties of molecular gels can be tuned in this way. Significant differences between thermal and in situ gels were found in properties such as thermal stability, thixotropic behavior or release of an entrapped dye. In situ synthesis-gelation has also been shown to provide gels in media such as oleic acid which cannot be jellified by conventional heating-cooling procedures.
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Affiliation(s)
- Miriam Fontanillo
- Departament de Química Inorgànica i Orgànica, Universitat Jaume I, 12071 Castelló, Spain
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96
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Fatás P, Bachl J, Oehm S, Jiménez AI, Cativiela C, Díaz Díaz D. Multistimuli-Responsive Supramolecular Organogels Formed by Low-Molecular-Weight Peptides Bearing Side-Chain Azobenzene Moieties. Chemistry 2013; 19:8861-74. [DOI: 10.1002/chem.201300796] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Indexed: 11/08/2022]
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97
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Edwards W, Smith DK. Dynamic Evolving Two-Component Supramolecular Gels—Hierarchical Control over Component Selection in Complex Mixtures. J Am Chem Soc 2013; 135:5911-20. [DOI: 10.1021/ja4017107] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- William Edwards
- Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K
| | - David K. Smith
- Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K
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98
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In situ formation of steroidal supramolecular gels designed for drug release. Molecules 2013; 18:3745-59. [PMID: 23529034 PMCID: PMC6270054 DOI: 10.3390/molecules18043745] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 03/19/2013] [Accepted: 03/21/2013] [Indexed: 11/17/2022] Open
Abstract
In this work, a steroidal gelator containing an imine bond was synthesized, and its gelation behavior as well as a sensitivity of its gels towards acids was investigated. It was shown that the gels were acid-responsive, and that the gelator molecules could be prepared either by a conventional synthesis or directly in situ during the gel forming process. The gels prepared by both methods were studied and it was found that they had very similar macro- and microscopic properties. Furthermore, the possibility to use the gels as carriers for aromatic drugs such as 5-chloro-8-hydroxyquinoline, pyrazinecarboxamide, and antipyrine was investigated and the prepared two-component gels were studied with regard to their potential applications in drug delivery, particularly in a pH-controlled drug release.
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99
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100
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Chemically programmed self-sorting of gelator networks. Nat Commun 2013; 4:1480. [DOI: 10.1038/ncomms2499] [Citation(s) in RCA: 208] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 01/15/2013] [Indexed: 12/22/2022] Open
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