Use Of Toxic Surfactants Research Articles

Microfluidic Synthesis of Hybrid TiO2-Anisotropic Gold Nanoparticles with Visible and Near-Infrared Activity

Anisotropic gold nanoparticles (AuNPs), with their unique physical and optical properties, are emerging as smart and key nanomaterials and are being exploited in many crucial fields. To further improve their range of action, anisotropic AuNPs have been coupled with semiconductors, mainly TiO2 (titania), receiving great interest as powerful platforms both in biomedicine and in catalytic applications. Such hybrid nanoparticles show new properties that arise from the synergic action of the components and rely on NP size, morphology, and arrangement. Therefore, continuous advances in design and fabrication of new hybrid titania@gold NPs (TiO2@AuNPs) are urgent and highly desirable. Here, we propose an effective protocol to produce multibranched AuNPs covered by a controlled TiO2 thin layer, exploiting a one-pot microfluidic process. The proposed method allows the in-flow and reliable synthesis of titania-functionalized-anisotropic gold nanoparticles by avoiding the use of toxic surfactants and controlling the titania shell formation. TiO2@AuNPs have been fully characterized in terms of morphology, stability, and biocompatibility, and their activity in photocatalysis has been tested and verified.

Designing an anti-inflammatory and tissue-adhesive colloidal dressing for wound treatment

Wound dressing materials are widely used to protect wounds from the external environment and to promote wound healing. However, conventional wound dressings lack tissue adhesive properties and anti-inflammatory functions, which lead to fibrosis and stricture, in cases such as gastrointestinal wounds after endoscopic surgery. In the current study, we report tissue-adhesive and anti-inflammatory properties of a wound dressing composed of corticosteroid-modified gelatin particles. Hydrocortisone (HC), which is a class of anti-inflammatory corticosteroid, was used to modify Alaska-pollock gelatin (ApGltn) to synthesize HC-modified ApGltn (HC-ApGltn). Microparticles (MPs) of HC-ApGltn were fabricated by adding ethanol in HC-ApGltn aqueous solution and performing thermal crosslinking (TC) without the use of toxic surfactants and crosslinking reagents. Modification of ApGltn with hydrophobic HC containing cholesterol backbone structure improved its adhesion strength to gastric submucosal tissues under wet conditions owing to hydrophobic interactions. This retention of adhesive property under wet conditions allows for stable protection of wounds from the external environment. We found that HC-ApGltn MPs were taken up by macrophages and they effectively suppressed morphological changes of LPS-activated macrophages and the expression level of the inflammatory cytokine. Robust tissue adhesive and anti-inflammatory MPs may serve as an advanced wound dressing that can protect wounds and suppress inflammatory responses for promoting wound healing.

Amino Acids for the Sustainable Production of Cu2O Materials: Effects on Morphology and Photocatalytic Reactivity

Photocatalytic technologies represent intriguing approaches for long-term environmental remediation strategies; however, approaches to sustainably generate the catalytic materials remain limited. Many methods require the use of toxic surfactants and potentially harsh conditions. As an alternative, bioinspired approaches present pathways toward the production of functional structures under ambient conditions. In this contribution, the effects of amino acids in the low-temperature production of Cu2O-based materials is examined, providing first principle information for the eventual de novo design of peptides that can control the structure/function relationship of these inorganic materials. These studies demonstrate that only a fraction of the 20 canonical amino acids (Arg, Cys, Glu, His, Lys, and Trp) possess specific control over the morphology and size of Cu2O materials during the synthetic process. This level of control is shown to directly affect the photocatalytic activity of the materials for the degradation of model organic pollutants. Taken together, these results provide intriguing new directions for the rational design of sustainable synthetic approaches for the production of catalytically important semiconductor metal oxide materials applied to long-term environmental remediation capabilities.

Use of RAFT macro-surfmers for the synthesis of transparent aqueous colloids with tunable interactions.

We propose a new method to produce fluorinated nanoparticles (NPs) based on ab initio reversible addition-fragmentation chain transfer (RAFT) emulsion polymerization without the use of toxic surfactants. NP size, surface charge, and chemistry can be controlled via the adoption of different macromolecular transfer agents produced via RAFT polymerization of amphiphilic monomers. Thanks to this versatility, interparticle interactions can be easily tuned by changing solvent composition and temperature. In addition, the refractive index and density of the solvent can simultaneously match those of the NPs by adding sodium polytungstate, an organic salt widely used for density gradient centrifugation. These colloids may be used as model systems for the study of self-assembly and aggregation in aqueous media when optical methods are required.

Tailoring the morphology of high molecular weight PLLA scaffolds through bioglass addition

Thermally induced phase separation (TIPS) has proven to be a suitable method for the preparation of porous structures for tissue engineering applications, and particular attention has been paid to increasing the pore size without the use of possible toxic surfactants. Within this context, an alternative method to control the porosity of polymeric scaffolds via the combination with a bioglass is proposed in this work. The addition of a bioactive glass from the 3CaO x P2O5-MgO-SiO2 system enables the porous structure of high molecular weight poly(l-lactic) acid (PLLA) scaffolds prepared by TIPS to be tailored. Bioglass acts as a nucleating catalyst agent of the PLLA matrix, promoting its crystallization, and the glass solubility controls the pore size. A significant increase in the pore size is observed as the bioglass content increases and scaffolds with large pore size (approximately 150 microm) can be prepared. In addition, the bioactive character of the scaffolds is proved by in vitro tests in synthetic plasma. The importance of this approach resides on the combination of the ability to tailor the porosity of polymeric scaffolds via the tunable solubility of bioglasses, without the use of toxic surfactants, leading to a composite structure with suitable properties for bone tissue engineering applications.