Max-Planck Institute of Colloids and Interfaces, Research Campus Golm, Potsdam, D-14424 Germany.
Langmuir. 2009 Dec 15;25(24):14037-43. doi: 10.1021/la9015433.
In this work, we report on the functionalization of layer-by-layer films with gold nanoparticles, microcapsules, and DNA molecules by spontaneous incorporation into the film. Exponentially growing films from biopolymers, namely, hyaluronic acid (HA) and poly-L-lysine (PLL), and linearly growing films from the synthetic polymers, namely, poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH), were examined for the embedding. The studied (PLL/HA)(24)/PLL and (PAH/PSS)(24)/PAH films are later named HA/PLL and PSS/PAH films, respectively. The HA/PLL film has been found to be more efficient for both particle and DNA embedding than PSS/PAH because of spontaneous PLL transport from the interior of the whole HA/PLL film to the surface in order to make additional contact with embedded particles or DNA. DNA and nanoparticles can be immobilized in HA/PLL films, reaching loading capacities of 1.5 and 100 microg/cm(2), respectively. The capacities of PSS/PAH films are 5 and 12 times lower than that for films made from biopolymers. Polyelectrolyte microcapsules adsorb irreversibly on the HA/PLL film surface as single particles whereas very poor interaction was observed for PSS/PAH. This intrinsic property of the HA/PLL film is due to the high mobility of PLL within the film whereas the structure of the PSS/PAH film is "frozen in". Gold nanoparticles and DNA form micrometer-sized aggregates or patches on the HA/PLL film surface. The diffusion of nanoparticles and DNA into the HA/PLL film is restricted at room temperature, but DNA diffusion is triggered by heating to 70 degrees C, leading to homogeneous filling of the film with DNA. The film has not only a high loading capacity but also can be activated by "biofriendly" near-infrared (IR) laser light, thanks to the gold nanoparticle aggregates on the film surface. Composite HA/PLL films with embedded gold nanoparticles and DNA can be activated by light, resulting in DNA release. We assume that the mechanism of the release is dependent on the disturbance in bonding between "doping" PLL and DNA, which is induced by local thermal decomposition of the HA/PLL network in the film when the film is exposed to IR light. Remote IR-light activation of dextran-filled microcapsules modified by gold nanoparticles and integrated into the HA/PLL film is also demonstrated, revealing an alternative release pathway using immobilized light-sensitive carriers (microcapsules).
在这项工作中，我们报告了通过自发掺入膜中来实现层层金纳米粒子、微胶囊和 DNA 分子功能化的方法。我们研究了从生物聚合物（即透明质酸 (HA) 和聚-L-赖氨酸 (PLL)）中指数生长的膜，以及从合成聚合物（即聚苯乙烯磺酸盐 (PSS) 和聚 (烯丙基胺盐酸盐) (PAH)）中线性生长的膜，以进行嵌入实验。研究的 (PLL/HA)(24)/PLL 和 (PAH/PSS)(24)/PAH 薄膜分别命名为 HA/PLL 和 PSS/PAH 薄膜。由于 PLL 从整个 HA/PLL 薄膜的内部自发运输到表面以与嵌入的粒子或 DNA 进行额外接触，因此 HA/PLL 薄膜对于粒子和 DNA 的嵌入更为有效。DNA 和纳米粒子可以固定在 HA/PLL 薄膜中，分别达到 1.5 和 100μg/cm(2)的负载能力。PSS/PAH 薄膜的负载能力比生物聚合物低 5 倍和 12 倍。聚电解质微胶囊不可逆地吸附在 HA/PLL 薄膜表面上作为单个粒子，而对于 PSS/PAH，观察到非常差的相互作用。HA/PLL 薄膜的这种固有性质是由于 PLL 在薄膜内的高迁移率，而 PSS/PAH 薄膜的结构是“冻结的”。金纳米粒子和 DNA 在 HA/PLL 薄膜表面形成微米级的聚集体或斑点。在室温下，纳米粒子和 DNA 扩散到 HA/PLL 薄膜中受到限制，但通过加热到 70°C 可以触发 DNA 扩散，从而使 DNA 均匀填充到薄膜中。该薄膜不仅具有高负载能力，而且由于薄膜表面上的金纳米粒子聚集体，可以通过“生物友好”的近红外 (IR) 激光激活。由于薄膜中的 HA/PLL 网络局部热分解，“掺杂”PLL 和 DNA 之间的键合受到干扰，导致嵌入金纳米粒子和 DNA 的复合 HA/PLL 薄膜可以通过光激活，从而实现 DNA 释放。我们假设，释放的机制依赖于“掺杂”PLL 和 DNA 之间的键合的破坏，这种破坏是由暴露在近红外光下时薄膜中 HA/PLL 网络的局部热分解引起的。我们还证明了通过金纳米粒子修饰的并整合到 HA/PLL 薄膜中的葡聚糖填充微胶囊的远程红外光激活，揭示了使用固定光敏载体（微胶囊）的替代释放途径。
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