Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education, Shandong University, Jinan 250100, China.
J Colloid Interface Sci. 2012 Apr 15;372(1):40-4. doi: 10.1016/j.jcis.2012.01.026. Epub 2012 Jan 24.
By AFM we report the successful modulation of shell structure (morphology and shell thickness) of microcapsules through tailoring molecular substituents of chitosan. The shell thickness of hollow (HPCS/SA)(n) (n=5, 7, 9) capsules is more than 3 times that of the (QACS/SA)(n) (n=5, 7, 9) capsules, due to less charges carried by the neutral -NH(2) substituent group and the induced coily conformation in HPCS, while more charges carried by the positively charged -N(CH(3))(3)(+) substituent and the induced extended conformation in QACS (HPCS: hydroxyl propyl chitosan; QACS: quaternary ammonium chitosan; SA: sodium alginate). The ultrathin shells of microcapsules assembled in this work by the layer-by-layer (LbL) self-assembly technique rather than the traditional method of mixing CS, SA and CaCl(2) enable the thickness modulation characterization by AFM on the atomic scale. These microcapsules with tunable shell thickness provide important guidance for potential drug delivery and sustained release.
我们通过原子力显微镜（AFM）报告了通过调整壳聚糖的分子取代基成功调节微胶囊的壳结构（形态和壳厚度）。由于中性-NH（2）取代基和 HPCS 中的诱导卷曲构象所携带的电荷较少，以及带正电荷的-N（CH（3））（3）（+）取代基和诱导的 QACS 中的伸展构象所携带的电荷较多，因此空心（HPCS/SA）（n）（n=5、7、9）胶囊的壳厚度是（QACS/SA）（n）（n=5、7、9）胶囊的 3 倍以上。（HPCS：羟丙基壳聚糖；QACS：季铵化壳聚糖；SA：海藻酸钠）。通过层层自组装技术（LbL）组装的微胶囊具有超薄的壳层，而不是传统的混合 CS、SA 和 CaCl2 的方法，这使得可以通过 AFM 在原子尺度上进行厚度调制表征。这些具有可调壳厚度的微胶囊为潜在的药物输送和持续释放提供了重要的指导。
