Dendrimer as nanocarrier for drug delivery

Dendrimers are novel three dimensional, hyperbranched globular nanopolymeric architectures. Attractive features like nanoscopic size, narrow polydispersity index, excellent control over molecular structure, availability of multiple functional groups at the periphery and cavities in the interior distinguish them amongst the available polymers. Applications of dendrimers in a large variety of fields have been explored. Drug delivery scientists are especially enthusiastic about possible utility of dendrimers as drug delivery tool. Terminal functionalities provide a platform for conjugation of the drug and targeting moieties. In addition, these peripheral functional groups can be employed to tailor-make the properties of dendrimers, enhancing their versatility. The present review highlights the contribution of dendrimers in the field of nanotechnology with intent to aid the researchers in exploring dendrimers in the field of drug delivery.     

纳米SiO2对原位分散聚合制备导电聚苯胺薄膜结构与性能的影响

在苯胺的化学氧化体系中,采用无机纳米微粒二氧化硅作为空间稳定剂,在玻璃基体表面直接制备了透明导电的聚苯胺薄膜,并与水溶性高分子聚乙烯吡咯烷酮(PVP)做稳定剂进行比较。采用SEM、紫外光谱、红外光谱和四探针电导率仪对薄膜的表观形貌、厚度、化学结构和电导率进行了表征。结果表明:稳定剂的存在有效抑制了溶液中宏观沉淀的生成,制得的薄膜表面光滑致密;与水溶性高分子聚乙烯吡咯烷酮(PVP)为稳定剂的情况相比较,纳米SiO2做稳定剂条件下,整个反应体系诱导期相对延长,反应速率相对缓慢,薄膜的生长速度也相对缓慢;薄膜的饱和厚度达到200nm左右,高于聚乙烯吡咯烷酮(PVP)做稳定剂的情况;所得薄膜的电导率要相对低一些,仍属于半导体范围;红外光谱分析发现制备的聚苯胺薄膜中无稳定剂存在,说明稳定剂未参与薄膜的生长聚合。