Surface-engineered hydroxyapatite nanocrystal/ poly(ε-caprolactone) hybrid scaffolds for bone tissue engineering

Nanostructured fusiform hydroxyapatite particles precipitated from aquaculture wastewater

The present work represents a new approach for the isolation of uniform nano particulate hydroxyapatite (HAp). The chemical characterization of a calcium phosphate product obtained from industrial trout farm aquaculture wastewater by two different routes, washing either with a basic aqueous medium (wash_NaOH) or followed by a further washing with ethanol (wash_EtOH), is explored. Characterization of the isolated materials includes morphology studies (SEM and TEM), structural (XRD, electron diffraction), compositional (EDX) and thermogravimetric analysis (TGA). The obtained products are a mixture of different compounds, with hydroxyapatite the predominant phase. The morphology is unusually nanometric size with fusiform shaped particles, such characteristics are ordinarily only obtained by synthetic routes. This process of phosphate precipitation represents a unique self-sufficient process to be compared to conventional chemical or biological practices for precipitating phosphate.

Folic acid modified clay/polymer nanocomposites for selective cell adhesion

A promising material, a folic acid modified poly(epsilon-caprolactone)/clay nanocomposite that allows selective cell adhesion and proliferation, was synthesized and characterized as a cell culture and biosensing platform.

In vitro biocompatibility and antimicrobial activity of poly(ε-caprolactone)/montmorillonite nanocomposites

A triblock copolymer based on poly(ε-caprolactone) (PCL) and 2-(N,N-diethylamino)ethyl methacrylate (DEAEMA)/2-(methyl-7-nitrobenzofurazan)amino ethyl acrylate (NBD-NAcri), was synthesized via atom transfer radical polymerization (ATRP). The corresponding chlorohydrated copolymer, named as PCL-b-DEAEMA, was prepared and anchored via cationic exchange on montmorillonite (MMT) surface. (PCL)/layered silicate nanocomposites were prepared through melt intercalation, and XRD and TEM analysis showed an exfoliated/intercalated morphology for organomodified clay. The surface characterization of the nanocomposites was undertaken by using contact angle and AFM. An increase in the contact angle was observed in the PCL/MMT(PCL-b-DEAEMA) nanocomposites with respect to PCL. The AFM analysis showed that the surface of the nanocomposites became rougher with respect to the PCL when MMTk10 or MMT(PCL-b-DEAEMA) was incorporated, and the value increased with the clay content. The antimicrobial activity of the nanocomposites against B. subtilis and P. putida was tested. It is remarkable that the biodegradation of PCL/MMT(PCL-b-DEAEMA) nanocomposites, monitored by the production of carbon dioxide and by chemiluminescence emission, was inhibited or retarded with respect to the PCL and PCL/1-MMTk10. It would indicate that nature of organomodifier in the clay play an important role in B. subtilis and P. putida adhesion processes. Biocompatibility studies demonstrate that both PCL and PCL/MMT materials allow the culture of murine L929 fibroblasts on its surface with high viability, very low apoptosis, and without plasma membrane damage, making these materials very adequate for tissue engineering.