Centre for Biomedical Engineering, Indian Institute of Technology, 110016 New Delhi, India.
Colloids Surf B Biointerfaces. 2011 Apr 1;83(2):204-13. doi: 10.1016/j.colsurfb.2010.11.007. Epub 2010 Nov 23.
Novel interpenetrating polymer network (IPN) nanogels composed of poly(acrylic acid) and gelatin were synthesised by one pot inverse miniemulsion (IME) technique. This is based on the concept of nanoreactor and cross-checked from template polymerization technique. Acrylic acid (AA) monomer stabilized around the gelatin macromolecules in each droplet was polymerized using ammonium persulfate (APS) and tetramethyl ethylene diamine (TEMED) in 1:5 molar ratio and cross-linked with N,N-methylene bisacrylamide (BIS) to form semi-IPN (sIPN) nanogels, which were sequentially cross-linked using glutaraldehyde (Glu) to form IPNs. Span 20, an FDA approved surfactant was employed for the formation of homopolymer, sIPN and IPN nanogels. Formation of stable gelatin-AA droplets were observed at 2% surfactant concentration. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) studies of purified nanogels showed small, spherical IPN nanogels with an average diameter of 255 nm. In contrast, sIPN prepared using the same method gave nanogels of larger size. Fourier-transform infrared (FT-IR) spectroscopy, SEM, DLS, X-ray photoelectron spectroscopy (XPS) and zeta potential studies confirm the interpenetration of the two networks. Leaching of free PAA chains in sIPN upon dialysis against distilled water leads to porous nanogels. The non-uniform surface of IPN nanogels seen in transmission electron microscopy (TEM) images suggests the phase separation of two polymer networks. An increase of N/C ratio from 0.07 to 0.17 (from PAA gel to IPN) and O/C ratio from 0.22 to 0.37 (from gelatin gel to IPN) of the nanogels by XPS measurements showed that both polymer components at the nanogel surface are interpenetrated. These nanogels have tailoring properties in order to use them as high potential drug delivery vehicles for cancer targeting.
通过一锅反相乳液（IME）技术合成了由聚丙烯酸（PAA）和明胶组成的新型互穿聚合物网络（IPN）纳米凝胶。这是基于纳米反应器的概念，并从模板聚合技术中得到验证。在每个液滴中，AA 单体稳定在明胶大分子周围，使用过硫酸铵（APS）和四甲基乙二胺（TEMED）以 1:5 的摩尔比聚合，并使用 N,N-亚甲基双丙烯酰胺（BIS）交联形成半互穿聚合物网络（sIPN）纳米凝胶，然后使用戊二醛（Glu）进一步交联形成 IPN。Span 20，一种 FDA 批准的表面活性剂，用于形成均聚物、sIPN 和 IPN 纳米凝胶。在 2%表面活性剂浓度下观察到稳定的明胶-AA 液滴的形成。纯化纳米凝胶的动态光散射（DLS）和扫描电子显微镜（SEM）研究表明，形成的 IPN 纳米凝胶具有小而球形的结构，平均直径为 255nm。相比之下，使用相同方法制备的 sIPN 纳米凝胶尺寸较大。傅里叶变换红外（FT-IR）光谱、SEM、DLS、X 射线光电子能谱（XPS）和 zeta 电位研究证实了两种网络的互穿。在蒸馏水透析过程中，sIPN 中游离 PAA 链的浸出导致形成多孔纳米凝胶。透射电子显微镜（TEM）图像中看到的 IPN 纳米凝胶不均匀的表面表明两种聚合物网络发生了相分离。XPS 测量表明，纳米凝胶的 N/C 比从 0.07 增加到 0.17（从 PAA 凝胶到 IPN），O/C 比从 0.22 增加到 0.37（从明胶凝胶到 IPN），这表明纳米凝胶表面的两种聚合物成分都发生了互穿。这些纳米凝胶具有可定制的性质，可用于作为癌症靶向的高潜力药物输送载体。
