最近，伊朗大不里士医科大学的Mehdi Jaymand和Morteza Eskandani通过静电纺丝的方法成功的制备了一种新型的含有超支化的脂肪族聚酯（HAP）、聚噻吩（PTh）和聚己内酯（PCL）的导电性支架。其具体的合成过程如下，首先，三（羟甲基）丙烷、2,2-双（羟甲基）丙酸（二-MAP）通过熔融缩聚反应合成HAP (G4;第四代)。接着，以DCC、NHS为催化剂，用2-噻吩乙酸修饰HAP，合成出噻吩功能化的G4大分子单体。然后，通过化学氧化共聚合的方法将噻吩单体和G4大分子单体聚合，合成出PTh包裹G4核的星型大分子（G4-PTh）。最后，通过静电纺丝的方法，将G4- PTh和PCL的溶液制备出导电性、生物相容性的纳米纤维。静电纺丝的纳米纤维通过粘附实验、小鼠成骨细胞（MC3T3-E1）的增殖实验、体外降解实验进行评估，进而说明这种材料在组织工程支架方面有一定的应用前景。
The last decade has witnessed the design and development of novel multifunctional materials for application in regeneration replacement of damaged or diseased tissues by delivering human extracellular matrix (ECM) components. The scaffolds for regenerative medicine must possess some properties as follows: (1) biocompatibility and biodegradability, (2) suitable microstructures, and mechanical characteristics, (3) proper surface topography and chemical composition, (4) simple and cost-effective fabrication technology. In many polymer materials，because of their unique physicochemical properties including excellent environmental-thermal stabilities，high electrical conductivities、mechanical strengths、magnetic、optical properties，ease synthesis and low costs, polythiophene (PTh), and its derivatives (especially poly(3,4-ethylenedioxythiophene)) have been witnessed an immense interest for the fabrication of conductive scaffolds.Furthermore, aliphatic polyesters may be an appropriate candidate for the synthetic desired scaffolds, because of their biocompatibility, biodegradability, and low costs. Among the aliphatic polyesters, the hyperbranched polyesters based on 2, 2- bis (methylol) propionic acid have stimulated great interest, mainly due to their highly branched structure and the large number of functional groups, unique physicochemical properties, and significant advantage for industrial and biomedical applications.The electrospinning is suggested as an efficient approach to prepare biocompatible conductive nanofibers to mimic the architecture and biological functions of the ECM. This technique has attracted a great deal of attention in the past decade for fabrication of conductive scaffolds, mainly due to high porosity, high surface-to-volume ratio, ultrathin continuous fibers, adjustable pore size distribution as well as its simplicity and more cost-effectivity.
The achievement in scientific research
Recently,Mehdi Jaymand and Morteza Eskandani who working in theTabriz University of Medical Sciences made the following outcome. A novel electrically conductive scaffold containing hyperbranched aliphatic polyester (HAP), polythiophene (PTh), and poly(e-caprolactone) (PCL) for regenerative medicine application was succesfully fabricated via electrospinning technique. For this purpose, the HAP (G4; fourth generation) was synthesized via melt polycondensation reaction from tris (methylol) propane and 2,2-bis(methylol)propionic acid (bis-MPA).Afterward, the synthesized HAP was functionalized with 2-thiopheneacetic acid in the presence of N,N-dicyclohexyl carbodiimide, and N-hydroxysuccinimide as coupling agent and catalyst, respectively, to afford a thiophene-functionalized G4 macromonomer .This macromonomer was subsequently used in chemical oxidation copolymerization with thiophene monomer to produce a starshaped PTh with G4 core (G4-PTh). The solution of the G4- PTh, and PCL was electrospun to produce uniform, conductive, and biocompatible nanofibers. The conductivity, hydrophilicity, and mechanical properties of these nanofibers were investigated. The biocompatibility of the electrospun nanofibers were evaluated by assessing the adhesion and proliferation of mouse osteoblast MC3T3-E1 cell line and in vitro degradability to demonstrate their potential uses as a tissue engineering scaffold.
A novel three-dimensional, conducting, biocompatible, and porous scaffold composed of hyperbranched aliphatic polyester, polythiophene, and poly(e-caprolactone) for application in regenerative medicine would be potentially used for tissue engineering.