Browsing by Author "Hsu, Shu-Min"

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A novel nanostructured supramolecular hydrogel self-assembled from tetraphenylethylene-capped dipeptides
(2016)
Yeh, Mei-Yu
;
Huang, Chen-Wei
;
Chang, Jui-Wen
;
Huang, Yu-Tang
;
Lin, Jhong-Hua
Herein, we report a tetraphenylethylene-diglycine (TPE-GG) hydrogelator from a systematic study of TPE-capped dipeptides with various amphiphilic properties. From a chemical design, we found that the hydrogelation of TPE-GG molecules can be utilized to generate supramolecular nanostructures with a large TPE-based nanobelt width (similar to 300 nm) and lateral dimension ratio (>30 fold). In addition, TPE-GG has the lowest molecular weight and minimum number of atoms compared to any TPE-capped peptide hydrogelator reported to date. This minimal self-assembled hydrogelator can fundamentally achieve the gel features compared with other TPE-capped peptides. A combined experimental and computational study indicates the pi-pi interactions, electrostatic interactions and hydrogen-bonding interactions are the major driving forces behind the formation of self-assembled nanobelts. This study demonstrates the importance of structure-property relationships and provides new insights into the design of supramolecular nanomaterials.
A supramolecular hydrogel self-assembled from pentafluorobenzyl-dipeptide
(2015-01-01)
Hsu, Shu-Min
;
Chang, Jui-Wen
;
Wu, Fang-Yi
;
Lin, Yu-Chun
;
Lai, Tsung-Sheng
We report a new aromatic-capped peptide amphiphile which is able to form a supramolecular hydrogel under neutral pH. This hydrogel can also be obtained by enzymatic transformation from the hydrogelator precursor. The newly discovered hydrogel has excellent biocompatibility for four different cell lines, thus making it a potentially useful scaffolding material for biomedical applications.
Electroactive Organic Dye Incorporating Dipeptides in the Formation of Self-Assembled Nanofibrous Hydrogels
(2014-10-01)
Liu, Yu-Hao
;
Hsu, Shu-Min
;
Wu, Fang-Yi
;
Cheng, Hsun
;
Yeh, Mei-Yu
In this study, we examined the self-assembly of four dipeptides conjugated with the electroactive dye naphthalenediimide (NDI). The presence of the NDI group at the N-terminus of Phe-Phe and Phe-Gly promoted the formation of one-dimensional (1-D) nanostructures and three-dimensional (3-D) colored hydrogels under both acidic and physiological conditions. The 1-D nanostructures of these gels were stabilized through intermolecular pi pi interactions of the conjugated systems and extended hydrogen bonding of the dipeptide units.
Functional Supramolecular Polymers: A Fluorescent Microfibrous Network in a Supramolecular Hydrogel for High-Contrast Live Cell-Material Imaging in 3D Environments
(2016-09-21)
Hsu, Shu-Min
;
Wu, Fang-Yi
;
Cheng, Hsun
;
Huang, Yu-Tang
;
Hsieh, Yi-Ru
A new bottom-up strategy based on aromatic peptide amphiphile is developed for a high-contrast visualization of 3D live cell-material imaging-something that has been difficult to achieve previously because of the problems associated with the diffraction of light by the nanosized peptide materials and the aggregation-caused quenching of aggregated pi-conjugated fluorophores in the nanostructures. This study reports an example of a novel supramolecular hydrogelator, naphthaleneimide-phenylalanine (NI-Phe), which forms a self-supporting hydrogel displaying a unique microfibrous network and promising aggregation-induced emission characteristics at pH 7.4. The storage modulus of the NI-Phe gel supports the mass of a cell for 3D cell culturing. This work illustrates a new dopant-free supramolecular approach, complementary to well-established doping procedures that should facilitate the development of live cell imaging in 3D scaffolding materials.
Intramolecular Interactions of a Phenyl/Perfluorophenyl Pair in the Formation of Supramolecular Nanofibers and Hydrogels
(2014-02-10)
Hsu, Shu-Min
;
Lin, Yu-Chun
;
Chang, Jui-Wen
;
Liu, Yu-Hao
;
Lin, Hsin-Chieh
A new system for the incorporation of a phenyl/perfluorophenyl pair in the structure of a peptide hydrogelator was developed. The strategy is based on the idea that the integration of an end-capped perfluorophenyl group and a phenylalanine with a phenyl moiety in the side chain forms an intramolecular phenyl/perfluorophenyl pair, which can be used to promote the formation of the supramolecular nanofibers and hydrogels. This work illustrates the importance of structure-hydrogelation relationship and provides new insights into the design of self-assembly nanobiomaterials.
Nanofibrous hydrogels self-assembled from naphthalene diimide (NDI)/amino acid conjugates
(2015-01-01)
Hsu, Ling-Huang
;
Hsu, Shu-Min
;
Wu, Fang-Yi
;
Liu, Yu-Hao
;
Nelli, Srinivasa Rao
The combination of a naphthalene diimide (NDI) group and a single amino-acid of serine (Ser) or lysine (Lys) can be used to promote the formation of a supramolecular hydrogel, which indicates the aromatic amino acid is not necessary to be used in the structural design of NDI-capped small molecule hydrogelators. An equimolar ratio of NDI-Ser and NDI-Lys can form a stable hydrogel under neutral conditions and its gel-to-sol transition temperature is higher than 37 degrees C. This work, as the first example of NDI-containing hydrogelators without aromatic rings in the side chains of amino acids, illustrates a new approach to design NDI-capped supramolecular hydrogels.
Remarkable influence of alkyl chain lengths on supramolecular hydrogelation of naphthalene diimide-capped dipeptides
(2015-01-01)
Zhan, Fu-Kai
;
Hsu, Shu-Min
;
Cheng, Hsun
;
Lin, Hsin-Chieh
;
材料科學與工程學系
The influence of aliphatic chain lengths on supramolecular hydrogelation of naphthalene diimide-capped dipeptides is described. The dependence of the gelation pH as a function of chain lengths reveals an inverse linear relationship and the gelation pH values cover a broad range from pH 2 to pH 9. In addition, the presence of a n-octyl tail in the hydrogelator could enhance the ability of self-assembly in dilute solution.
Self-assembly and hydrogelation from multicomponent coassembly of pentafluorobenzyl-phenylalanine and pentafluorobenzyl-diphenylalanine
(2015-01-01)
Hsu, Shu-Min
;
Wu, Fang-Yi
;
Lai, Tsung-Sheng
;
Lin, Yu-Chun
;
Lin, Hsin-Chieh
To screen the possibility of forming self-assembled hydrogels under physiological pH, various molar ratios of the hydrogelators based on pentafluorobenzyl-phenylalanine (PFB-F) and pentafluorobenzyl-diphenylalanine (PFB-FF) were studied. The equimolar ratio of PFB-F and PFB-FF formed coassembled nanofibers and a self-supporting hydrogel at the physiological pH of 7.4. The spectroscopic characterization of the blend gel indicates that pi-pi interactions and hydrogen-bonding interactions are the major driving forces behind the coassembly. In addition, we also prove that the blend hydrogel is biocompatible, thus making it a scaffolding material for biomedical applications. In this work, the utility of two distinct hydrogelators to promote coassembly under physiological condition expands the repertoire of noncovalent interactions that can be used in the development of sophisticated noncovalent biomaterials.
The effect of fluorine on supramolecular hydrogelation of 4-fluorobenzyl-capped diphenylalanine
(2015-01-01)
Wu, Fang-Yi
;
Hsu, Shu-Min
;
Cheng, Hsun
;
Hsu, Ling-Huang
;
Lin, Hsin-Chieh
With the replacement of only one hydrogen atomby fluorine, 4-fluorobenzyl-diphenylalanine was able to form a transparent hydrogel, while benzyl-diphenylalanine did not under similar conditions, indicating the remarkable effect of fluorine on supramolecular hydrogelation.
The role of aromatic side chains on the supramolecular hydrogelation of naphthalimide/dipeptide conjugates
(2018-03-21)
Hsu, Shu-Min
;
Chakravarthy, Rajan Deepan
;
Cheng, Hsun
;
Wu, Fang-Yi
;
Lai, Tsung-Sheng
Herein, the influence of an amino acid side chain on the structural and functional properties of hydrogels has been described. In this study, four new hydrogelators based on the conjugates of dipeptides and naphthalimide (NI) have been designed, synthesized, and examined. Homopeptide 1 (NI-FF) of the phenylalanine residue forms a weak hydrogel or a viscous solution of worm-like micelles under basic conditions. On the other hand, dipeptide conjugates of 2 (NI-FY), 3 (NI-YF), and 4 (NI-YY), containing additional hydroxyl groups as tyrosine residues, can self-assemble into supramolecular hydrogels under physiological pH conditions. UV-vis, IR, and rheological studies clearly indicate the formation and stability of these dipeptide hydrogels. The TEM results revealed that the hydrogels (1-4) self-assembled into a nanofibrous morphology. Furthermore, the cell culture results show that NI-YF has better cell compatibility as compared to NI-FY and NI-YY and thus shows potential to be used as a hydrogel biomaterial. Overall, this study highlights the importance of the structure-hydrogelation relationship and provides new insights into the design of self-assembled peptide amphiphiles.