Polymer Nanofibers

Polymers consisting of but not limited to poly thiophene, polypyrrole and poly aniline have been extensively used to make polymer nanofibers. In general, any metal that can be electroplated has most likely appeared in a nanowire. Semiconductors, polymers, and insulators have also been used in the design of nanowires.Furthermore, different metals can be plated in succession to give striped nanowires. 

The polymer resulting from oxidation of 3,5-dimethyl aniline with palladium was also studied by transmission electron microscopy (Mallick et al. 2005). As it turned out, the polymer was formed in nanofibers. During oxidative polymerization, palladium ions were reduced and formed palladium metal. The generated metal was uniformly dispersed between the polymer nanofibers as nanoparticles of 2 mm size. So, Mallick et al. (2005) achieved a polymer- metal intimate composite material. This work should be juxtaposed to an observation by Newman and Blanchard (2006) that reaction between 4-aminophenol and hydrogen tetrachloroaurate leads to polyaniline (bearing hydroxyl groups) and metallic gold as nanoparticles. Such metal nanoparticles can well be of importance in the field of sensors, catalysis, and electronics with improved performance. 

Polymer nanofiber networks consisting of achiral polyaniline were prepared by Epstein et al. (3) by oxidizing aniline with ammonium peroxydisulfate and then doping with methanesulfonic acid. 

S. Curgul et al Molecular dynamics simulation of size-dependent structural and thermal properties of polymer nanofiber. Macromolecules 40, 8483-8489 (2007)... 

Electrospun polymer nanofibers with the smallest fiber diameter were obtained with the highest electrical conductivity. This interprets that the drop in the size of the fibers was due to the increased electrical conductivity [50]. 

Z-M Huang, Y.-Z. Zhang, M. Kotak, S. Ramakrishna. 2003. A review on polymer nanofibers by eleetrospinning and their applications in nanocomposites. Composites Science and Technology, 63. pp.2223-2253. 

One of the most common ways to create a HAp coating on polymer nanofibers is immersing them in SBF, which has ion concentrations similar to that of human blood plasma (Table 5) [131]. Though SBF immersion is often utilized as a method... 

The last method to be discussed, which is used to form polymer/ceramic composites by electrospinning, is extremely different to the methods previously described, but worth mentioning. Zuo et al. [129] used a method to create a composite scaffold that is actually the reverse of what most people are doing. Instead of mineralizing the nanofibers, Zuo et al. actually incorporated electrospun polymer nanofibers into a ceramic bone cement in order to form a composite scaffold. It was found that by incorporating electrospun nanofibers into the cement, the scaffold became less brittle and actually behaved similarly to that of a ductile material because of the fibers. Composite scaffolds with different polymers and fiber diameters were then tested in order to determine which scaffold demonstrated the most ideal mechanical properties. However, no cell studies were conducted and this method would most likely be used for a bone substitute instead of for bone regeneration applications. 

Fig. 14 Methods for incorporating biomolecules into/on polymer nanofibers [40]...

Sun ZC et al (2003) Compound core-shell polymer nanofibers by co-electrospinning. Adv Mater 15(22) 1929-1932... 

Highly Aligned Polymer Nanofiber Structures Fabrication and Applications in Tissue Engineering... 

Polymer nanofibers can be directly drawn from a viscous polymer solution or melt when a droplet of polymer solution is mechanically stretched [6]. For example, the tip of a rod was dipped in a polymer melt and simply pulled out to form nanofibers with diameters as low as 60 nm and lengths up to 500 mm [7]. Resulting nanofibers can be manually oriented into aligned arrays or formed into arrays by automated... 

Although aligned polymer nanofibers have some similarities to namral ECM, it is vital to tissue regeneration that resident cells produce their own natural matrix to compliment or replace the engineered scaffold. Substrate microstnicmre has pronounced effects on both the amount of ECM produced by resident cells and the architecture of that matrix. Increased ECM production has been observed in cells cultured on nanofibrous substrates compared to those on flat substrates and large (15 pm) microfibers [106, 135], The specific fiber diameter of nanofibrous substrates may also affect the ECM production of attached ceUs [129],... 

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