Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
Biomaterials. 2025 Mar;314:122812. doi: 10.1016/j.biomaterials.2024.122812. Epub 2024 Sep 4.
This work establishes the design of a fully synthetic, shear-thinning hydrogel platform that is injectable and can isolate engineered, allogeneic cell therapies from the host. We utilized RAFT to generate a library of linear random copolymers of N,N-dimethylacrylamide (DMA) and 2-vinyl-4,4-dimethyl azlactone (VDMA) with variable mol% VDMA and degree of polymerization. Poly(DMA-co-VDMA) copolymers were subsequently modified with either adamantane (Ad) or β-cyclodextrin (Cd) through amine-reactive VDMA to prepare hydrogel precursor macromers containing complementary guest-host pairing pendant groups that, when mixed, form shear-thinning hydrogels. Rheometric evaluation of the hydrogel library enabled identification of lead macromer structures comprising 15 mol% pendants (Ad or Cd) and a degree of polymerization of 1000; mixing of these Ad and Cd functionalized precursors yielded hydrogels possessing storage modulus above 1000 Pa, tan(δ) values below 1 and high yield strain, which are target characteristics of robust but injectable shear-thinning gels. This modular system proved amenable to nanoparticle integration with surface-modified nanoparticles displaying Ad. The addition of the Ad-functionalized nanoparticles simultaneously improved mechanical properties of the hydrogels and enabled extended hydrogel retention of a model small molecule in vivo. In studies benchmarking against alginate, a material traditionally used for cell encapsulation, the lead hydrogel showed significantly less fibrous encapsulation in a subcutaneous implant site. Finally, this platform was utilized to encapsulate and extend in vivo longevity of inducible transgene-engineered mesenchymal stem cells in an allogeneic transplant model. The hydrogels remained intact and blocked infiltration by host cells, consequently extending the longevity of grafted cell function relative to a benchmark, shear-thinning hyaluronic acid-based gel. In sum, the new synthetic, shear-thinning hydrogel system presented here shows potential for further development as an injectable platform for delivery and in situ drug modulation of allograft and engineered cell therapies.
这项工作建立了一个完全合成的、剪切稀化的水凝胶平台的设计，该平台可注射，并可将工程化的同种异体细胞疗法与宿主隔离。我们利用 RAFT 生成了一系列 N,N-二甲基丙烯酰胺（DMA）和 2-乙烯基-4,4-二甲基恶唑啉（VDMA）的线性无规共聚物的库，其中 VDMA 的摩尔比和聚合度可变。随后，通过胺反应性 VDMA 将聚（DMA-co-VDMA）共聚物修饰为金刚烷（Ad）或β-环糊精（Cd），以制备含有互补主客体对挂接基团的水凝胶前体大分子单体，当混合时，这些基团形成剪切稀化水凝胶。对水凝胶库的流变学评估使我们能够确定先导大分子单体结构，其包含 15 mol%的侧基（Ad 或 Cd）和聚合度为 1000；这些 Ad 和 Cd 功能化前体的混合产生了具有高于 1000 Pa 的储能模量、低于 1 的 tan(δ)值和高屈服应变的水凝胶，这些是稳健但可注射的剪切稀化凝胶的目标特征。这个模块化系统被证明适用于纳米粒子的整合，表面修饰的纳米粒子显示出 Ad。添加 Ad 功能化的纳米粒子同时提高了水凝胶的机械性能，并使模型小分子在体内的水凝胶保留时间延长。在与传统用于细胞封装的海藻酸盐材料进行基准比较的研究中，领先的水凝胶在皮下植入部位显示出明显较少的纤维状封装。最后，该平台被用于封装和延长同种异体移植模型中诱导型转基因工程间充质干细胞的体内寿命。水凝胶保持完整，并阻止宿主细胞的渗透，从而相对于基准的剪切稀化透明质酸凝胶延长了移植物细胞功能的寿命。总之，这里提出的新型合成的、剪切稀化的水凝胶系统显示出作为用于同种异体和工程化细胞疗法的递送和原位药物调节的可注射平台进一步开发的潜力。
