TiO2/rectorite-trapped cellulose composite nanofibrous mats for multiple heavy metal adsorption

The anthropogenic release of highly toxic heavy metals into the environment presents a huge challenge for ecosystems and human society. Recoverable and efficient adsorption materials could be obtained by trapping inorganic adsorbents (e.g., TiO₂ nanoparticles and rectorite (REC)), in a natural polymer matrix. In this study, a series of cellulose-TiO₂/REC composite nanofibrous mats were fabricated via electrospinning. The interactions between inorganic adsorbents and cellulose molecules improved the thermal stability, surface area, tensile strength and adsorption capacity of the mats. We focused on the adsorption of Pb²⁺, Cu²⁺ and Cd²⁺ from acidic solutions onto cellulose-TiO₂/REC composite nanofibrous mats in multiple systems because the magnitudes of heavy metal concentrations in wastewater typically varied. The maximum total adsorption capacity of 69.81 mg/g was obtained by Cellulose-TiO₂/REC_2:1 nanofibrous mats. The composite nanofibrous mats successfully trapped TiO₂ nanoparticles, and the obtained cellulose-TiO₂/REC nanofibrous mats could be used to remove heavy metals from acidic wastewater.

Antimicrobial activity and cytotoxicity of nanofibrous mats immobilized with polysaccharides-rectorite based nanogels

Rectorite (REC)-encapsulated lysozyme (LY)-alginate (ALG) nanogels (NGs) were prepared by adding ALG-REC composites suspensions into LY solutions at the mass ratio of 1:2. The morphology of the NGs and the NGs-assembled nanofibrous mats were studied by transmission electron microscope and field emission scanning electron microscopy, respectively. The composition of NGs-immobilized nanofibrous mats was detected by X-ray photoelectron spectroscopy. The NGs-assembled nanofibrous mats with the addition of REC could enhance the inhibition against Escherichia coli and Staphylococcus aureus. Additionally, NGs-coated mats reduced the toxicity of cellulose mats on mouse lung fibroblasts using MTT assay. Besides, the addition of REC in the NGs improved the cell compatibility of NGs-assembled nanofibrous mats.

Bioactive electrospun fish sarcoplasmic proteins as a drug delivery system

Nano-microfibers were made from cod (Gadus morhua) sarcoplasmic proteins (FSP) (Mw<200kDa) using the electrospinning technique. The FSP fibers were studied by scanning electron microscopy, and the fiber morphology was found to be strongly dependent on FSP concentration. Interestingly, the FSP fibers were insoluble in water. However, when exposed to proteolytic enzymes, the fibers were degraded. The degradation products of the FSP fibers proved to be inhibitors of the diabetes-related enzyme DPP-IV. The FSP fibers may have biomedical applications, among others as a delivery system. To demonstrate this, a dipeptide (Ala-Trp) was encapsulated into the FSP fibers, and the release properties were investigated in gastric buffer and in intestinal buffer. The release profile showed an initial burst release, where 30% of the compound was released within the first minute, after which an additional 40% was released (still exponential) within the next 30min (gastric buffer) or 15min (intestinal buffer). The remaining 30% was not released in the timespan of the experiment.