Adv Mater：基于仿生层状膜网络的超高含水量强韧水凝胶

     水凝胶作为关键的结构生物材料，其超高含水量与力学强韧性的性能平衡始终是领域核心挑战——传统合成水凝胶（如分子网络或纳米纤维网络）普遍存在两大局限：一是缺乏类生物的高阶微/纳米结构，二是在含水量超过90 wt.%时难以维持优异力学性能，这严重限制了其在生物医学领域的应用。

      针对这一难题，湖南大学王建锋教授团队与夏鹏辉课题组在《Advanced Materials》发表突破性研究，首次揭示水母中胶层通过长程有序层状膜网络（LM网络）实现性能协同：该网络以刚性结晶膜为结构单元，其中晶体沿膜平面取向排列，胶原链跨膜连接，使中胶层在含水量≈96 wt.%时仍能保持媲美软组织的力学性能（强度1.27±0.11 MPa、模量0.83±0.09 MPa），通过有效抗形变和分散应力传递实现结构稳定。基于此机制，团队创新提出“蒸发诱导相分离预构建随机膜网络 + 面内拉伸与NaOH处理诱导取向结晶”的仿生制备策略，成功开发出壳聚糖基仿水母结构水凝胶（LM-CS水凝胶）。该材料含水量达91.8 wt%，同时展现出5.2±0.3 MPa的模量与6.5±0.4 MPa的强度，性能超越现有合成及生物水凝胶，并兼具面内各向同性、生理稳定性和生物相容性。本研究不仅揭示了LM网络的结构机制，更为组织工程、生物医学器件等领域提供了理想的结构生物材料候选方案，标志着仿生水凝胶研究从基础探索向临床转化迈出关键一步。

• 首次破解水凝胶 “超高含水量 - 力学强韧性” 矛盾的核心机制：研究首次通过材料表征技术揭示了水母中胶层的长程有序层状膜网络（LM网络）结构 —— 以刚性结晶膜为基础单元，晶体沿膜平面定向排列，且胶原组成链可跨越多膜连接处形成稳定连接。此前这一关键结构机制尚未被明确揭示，从根本上打破了 “高含水量必然导致材料力学脆弱” 的传统认知

• 提出普适性的仿水母 LM 网络水凝胶制备技术路径：针对仿生结构的可转化问题，研究开发了“蒸发诱导相分离预构网络+面内拉伸/NaOH 处理强化” 两步法。该方法无需复杂设备，且明确了 “预构随机膜保证连接性、后续处理实现取向与结晶” 的核心逻辑，为其他聚合物体系制备高性能仿生水凝胶提供了可复用的技术范式

• 实现兼具多性能优势的仿生水凝胶突破：基于上述机制与方法制备的壳聚糖水凝胶（LM-CS 水凝胶），不仅实现91.8 wt%的超高含水量，更达到 5.2±0.3 MPa 的模量与 6.5±0.4 MPa 的强度，性能显著超越现有分子网络、纳米纤维网络等合成水凝胶及多数生物水凝胶；同时具备面内各向同性、优异生理稳定性与良好生物相容性，可加工为二尖瓣等仿生器件（10 万次循环后性能保留超 95%），为组织工程、生物医学器件等领域提供了理想的结构生物材料。

  
  

Fig. 1 | Mechanical robustness and laminated membranous network of ielyhsh mesoglea. a) lelyhsh. b) Photograph of ielyhsh bel.c) Comparisorof mechanical robustess li.. strength, modulusl and water content ofielvfsh bel's mesoplea and other soft tissues, The data used are summarizedin Table Sl (supporting information). d) Photograph of jelyish mesoglea. e,f) Scanning electron microscope (SEM) images for xz (e) and yz (fplanes, showing a long:range-ordered laminated structure. g-i Enlarged views for observation of laminated arangement (g), single lamellar membrane(h), bridged membrane between lamellar membranes (i). j) smallangle Xray scatering (AXS) measurements for jelyfsh mesoglea and obtained 2D patterns. k) fitted azimuthal angle profles for xz, yz and xy planes. ll wide angle Xray difraction (wXRD) profle. m) schematic ilustration ofcrystalline collagen network within membranes.

Fig. 2 |Preformation of random membranous network through phase separation. a) Macroscopic change from solution to soft gel (stage I: 0–2 h), then to rigid gel (stage II: 2–12 h) by evaporating acetic acid and water slowly from CS/acetic acid /glycerol/water solution. b) Schematic illustration for structural change underlying evaporation, including formation of a crosslinked molecular network via sparse hydrogen bonds in stage I, and then formation of a random membranous network via dense hydrogen bond-caused phase separation in stage II. c) Change of storage (G') and loss moduli (G") with evaporation time. d) Mass loss of water and acetic acid with evaporation time. e) Change of FTIR peaks with evaporation time, exhibiting obvious weakening of O-H/C=O peak and NH³⁺ peak, as well as intensification and blueshifts of NH₂ peak.f Changes of 2D SAXS patterns and profiles Iq²vs q with evaporation time, exhibiting a dramatic increase in scattering intensity after 2 h. g₁-g₃) SEM images after evaporation for 4 h (g₁) ,8h (g₂) and 12 h (g₃), showing evolution of phase-separated morphology in stage II from discrete vesicles to random membranous network. h,i) SEM images for the sample with evaporation for 12 h and removal of glycerol by alkaline aqueous solution soaking, showing a random membranous network structure.

Fig. 3 | Transformation from random to laminated membranous networks. a) Schematic illustration for structural transformation through in-plane stretching RM-CS glycerogel and soaking it in NaOH solution. This process aligns random membranes and crystalizes CS chains, leading to a LM-CS hydrogel. b) Photograph of LM-CS hydrogel. c,d) SEM images for x-z (c) and y-z (d) planes of LM-CS hydrogel, showing a long-range-ordered laminated membranous network. e–g) Enlarged views for observation of membrane-surrounded flat pore (e), junction of lamellar and bridged membranes (f), and nanofibrous network within membrane-surrounded pores (g). h) WXRD curve of LM-CS hydrogel, in comparison to RM-CS glycerogel. i) 2D SAXS patterns and fitted azimuthal angle profiles for x-z, y-z, and x-y planes of LM-CS hydrogel. j) Tensile stress–strain curves of LM-CS hydrogel, in comparison to RM-CS glycerogel.

Fig. 4 | Mechanical advantage of laminated membranous network hydrogel. a–d) Confocal images and tensile curves of LM-CS hydrogel (a) for comparison with those of OF-CS (b), F-CS (c), and C-CS (d) hydrogels. e) Strength and modulus of LM-CS, OF-CS, F-CS, and C-CS hydrogels. f,g) Ashby diagrams of tensile strength vs water content (f), and tensile modulus vs water content (g) for LM-CS hydrogel and other structured hydrogels reported previously. The data used are summarized in Table S3 (Supporting Information). h) Schematic of the device to carry out solution flow impact test for assessing the dynamic robustness of LM-CS hydrogels. i) Schematic of open and close states of mitral valve-like hydrogels during solution flow impact. j) Opening pressure at an increasing flow velocity. k) Change of opening pressure with cyclic solution flow impact at a flow velocity of 240 mL min 240 mL min^-1 、 Data are presented as mean values ±SD, n=3