Combinatorial effects of charge characteristics and hydrophobicity of silk fibroin on the sorption and release of charged dyes.

The present study was designed to examine the influence of the charge characteristics of silk fibroin on the sorption and release of charged dyes by varying the pH values of the sorption and release media as well as types of charged dyes. Negatively charged dyes (phenol red and chromotrope 2R) and positively charged dyes (crystal violet and indoine blue) were used as the model compounds. Silk fibroin films were prepared by using a solution casting technique.

Rhamnolipid biosurfactants: production and their potential in environmental biotechnology.

Certain species of Pseudomonas are able to produce and excrete a heterogeneous mixture of biosurfactants with a glycolipid structure. These are known as rhamnolipids. In the biosynthetic process, rhamnolipid production is governed by both the genetic regulatory system and central metabolic pathways involving fatty acid synthesis, activated sugars and enzymes.

In vitro and in vivo release of basic fibroblast growth factor using a silk fibroin scaffold as delivery carrier.

Two different solvents were used to prepare two types of silk fibroin scaffolds via the salt-leaching technique, i.e., hexafluoroisopropanol (HFIP) and water.

Miscibility and biodegradability of silk fibroin/carboxymethyl chitin blend films.

Blend films of silk fibroin and carboxymethyl chitin were prepared by solution casting using water as a cosolvent. The blend films were subjected to post-treatment with an aqueous methanol solution to induce beta-sheet formation of silk fibroin. The miscibility of the blend films both before and after methanol treatments was investigated in terms of chemical interactions, morphologies, thermal properties, and crystal structures by using FTIR spectroscopy, SEM, DSC, and XRD.

Structural and physicochemical characterization of crude biosurfactant produced by Pseudomonas aeruginosa SP4 isolated from petroleum-contaminated soil.

Pseudomonas aeruginosa strain SP4, isolated from petroleum-contaminated soil in Thailand, was used to produce a biosurfactant from a nutrient broth with palm oil as the carbon source. The key components of the crude biosurfactant were fractionated by using HPLC-ELSD technique. With the use of ATR-FTIR spectroscopy, in combination with (1)H NMR and MS analyses, chemical structures of the fractionated components of the crude biosurfactant were identified as rhamnolipid species.

Preparation and characterization of microwave-treated carboxymethyl chitin and carboxymethyl chitosan films for potential use in wound care application.

CM-chitin and CM-chitosan films were successfully crosslinked by microwave treatment. Crosslinking of the microwave-treated CM-chitin films involved mainly the carboxylate and the secondary alcohol groups, while crosslinking of microwave-treated CM-chitosan films involved the carboxylate and the amino groups. In addition, the crystallinity of CM-chitin increased with increasing microwave treatment time, whereas an increase in the crystallinity of the microwave-treated CM-chitosan films was not observed.