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Jiang C, Zhao C, Xu P, Song Q, Tao X, Lin S. Effects of Secondary Structures and pH on the Self-Assembly of Poly(ethylene glycol)- b-polytyrosine. Biomacromolecules 2024; 25:5028-5038. [PMID: 38950188 DOI: 10.1021/acs.biomac.4c00437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/03/2024]
Abstract
Different from conventional synthetic polymers, polypeptides exhibit a distinguishing characteristic of adopting specific secondary structures, including random coils, α-helixes, and β-sheets. The conformation determines the rigidity and solubility of polypeptide chains, which further direct the self-assembly and morphology of the nanostructures. We studied the effect of distinct secondary structures on the self-assembly behavior of polytyrosine (PTyr)-derived amphiphilic copolymers. Two block copolymers of enantiopure poly(ethylene glycol)-b-poly(l-tyrosine) (PEG-b-P(l-Tyr)) and racemic poly(ethylene glycol)-b-poly(dl-tyrosine) (PEG-b-P(dl-Tyr)) were synthesized through the ring-opening polymerization of l-tyrosine N-thiocarboxyanhydride (l-Tyr-NTA) and dl-tyrosine N-thiocarboxyanhydride (dl-Tyr-NTA), respectively, by using poly(ethylene glycol) amine as the initiator. PEG44-b-P(l-Tyr)10 adopts a β-sheet conformation and self-assembles into rectangular nanosheets in aqueous solutions, while PEG44-b-P(dl-Tyr)9 is primarily in a random coil conformation with a tiny content of β-sheet structures, which self-assembles into sheaf-like nanofibrils. A pH increase results in the ionization of phenolic hydroxyl groups, which decreases the β-sheet content and increases the random coil content of the PTyr segments. Accordingly, PEG44-b-P(l-Tyr)10 and PEG44-b-P(dl-Tyr)9 self-assemble to form slender nanobelts and twisted nanoribbons, respectively, in alkaline aqueous solutions. The secondary structure-driven self-assembly of PTyr-derived copolymers is promising to construct filamentous nanostructures, which have potential for applications in controlled drug release.
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Affiliation(s)
- Caixia Jiang
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Chonghao Zhao
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Peng Xu
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Qipeng Song
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Xinfeng Tao
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Shaoliang Lin
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
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Wang KH, Liu CH, Tan DH, Nieh MP, Su WF. Block Sequence Effects on the Self-Assembly Behaviors of Polypeptide-Based Penta-Block Copolymer Hydrogels. ACS APPLIED MATERIALS & INTERFACES 2024; 16:6674-6686. [PMID: 38289014 PMCID: PMC10859891 DOI: 10.1021/acsami.3c18954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 01/16/2024] [Accepted: 01/17/2024] [Indexed: 02/09/2024]
Abstract
Peptide-based hydrogels have great potential for applications in tissue engineering, drug delivery, and so on. We systematically synthesize, characterize, and investigate the self-assembly behaviors of a series of polypeptide-based penta-block copolymers by varying block sequences and lengths. The copolymers contain hydrophobic blocks of poly(γ-benzyl-l-glutamate) (PBG, Bx) and two kinds of hydrophilic blocks, poly(l-lysine) (PLL, Ky) and poly(ethylene glycol) (PEG, EG34), where x and y are the number of repeating units of each block, where PBG and PLL blocks have unique functions for nerve regeneration and cell adhesion. It shows that a sufficient length of the middle hydrophilic segment capped with hydrophobic end PBG blocks is required. They first self-assemble into flower-like micelles and sequentially form transparent hydrogels (as low as 2.3 wt %) with increased polymer concentration. The hydrogels contain a microscale porous structure, a desired property for tissue engineering to facilitate the access of nutrient flow for cell growth and drug delivery systems with high efficiency of drug storage. We hypothesize that the structure of Bx-Ky-EG34-Ky-Bx agglomerates is beyond micron size (transparent), while that of Ky-Bx-EG34-Bx-Ky is on the submicron scale (opaque). We establish a working strategy to synthesize a polypeptide-based block copolymer with a wide window of sol-gel transition. The study offers insight into rational polypeptide hydrogel design with specific morphology, exploring the novel materials as potential candidates for neural tissue engineering.
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Affiliation(s)
- Ke-Hsin Wang
- Department
of Materials Science and Engineering, National
Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Chung-Hao Liu
- Polymer
program, Institute of Materials Science, University of Connecticut, 25 King Hill Road, Unit 3136, Storrs, Connecticut 06269-3136, United States
| | - Dun-Heng Tan
- Department
of Materials Science and Engineering, National
Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Mu-Ping Nieh
- Polymer
program, Institute of Materials Science, University of Connecticut, 25 King Hill Road, Unit 3136, Storrs, Connecticut 06269-3136, United States
- Department
of Chemical and Biomolecular Engineering, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Wei-Fang Su
- Department
of Materials Science and Engineering, National
Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
- Department
of Materials Engineering, Ming-Chi University
of Technology, 84 Gungjuan
Rd., Taishan Dist, New Taipei City 243303, Taiwan
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Tseng YH, Ma TL, Tan DH, Su AJA, Washington KM, Wang CC, Huang YC, Wu MC, Su WF. Injectable Hydrogel Guides Neurons Growth with Specific Directionality. Int J Mol Sci 2023; 24:ijms24097952. [PMID: 37175657 PMCID: PMC10178216 DOI: 10.3390/ijms24097952] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/19/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
Visual disabilities affect more than 250 million people, with 43 million suffering from irreversible blindness. The eyes are an extension of the central nervous system which cannot regenerate. Neural tissue engineering is a potential method to cure the disease. Injectability is a desirable property for tissue engineering scaffolds which can eliminate some surgical procedures and reduce possible complications and health risks. We report the development of the anisotropic structured hydrogel scaffold created by a co-injection of cellulose nanofiber (CNF) solution and co-polypeptide solution. The positively charged poly (L-lysine)-r-poly(L-glutamic acid) with 20 mol% of glutamic acid (PLLGA) is crosslinked with negatively charged CNF while promoting cellular activity from the acid nerve stimulate. We found that CNF easily aligns under shear forces from injection and is able to form hydrogel with an ordered structure. Hydrogel is mechanically strong and able to support, guide, and stimulate neurite growth. The anisotropy of our hydrogel was quantitatively determined in situ by 2D optical microscopy and 3D X-ray tomography. The effects of PLLGA:CNF blend ratios on cell viability, neurite growth, and neuronal signaling are systematically investigated in this study. We determined the optimal blend composition for stimulating directional neurite growth yielded a 16% increase in length compared with control, reaching anisotropy of 30.30% at 10°/57.58% at 30°. Using measurements of calcium signaling in vitro, we found a 2.45-fold increase vs. control. Based on our results, we conclude this novel material and unique injection method has a high potential for application in neural tissue engineering.
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Affiliation(s)
- Yun-Hsiu Tseng
- Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Tien-Li Ma
- Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Dun-Heng Tan
- Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - An-Jey A Su
- Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Kia M Washington
- Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Chun-Chieh Wang
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Yu-Ching Huang
- Department of Materials Engineering, Ming Chi University of Technology, New Taipei 24301, Taiwan
| | - Ming-Chung Wu
- Department of Chemical and Materials Engineering, Chang Gung University, Taoyuan 33302, Taiwan
- Center for Green Technology, Chang Gung University, Taoyuan 33302, Taiwan
- Division of Neonatology, Department of Pediatrics, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan
| | - Wei-Fang Su
- Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
- Department of Materials Engineering, Ming Chi University of Technology, New Taipei 24301, Taiwan
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