A new approach for single cell microencapsulation in an oil-in-water (o/w) Pickering emulsion is presented. The water/paraffin emulsions were stabilized by amine-functionalized silica nanoparticles. The droplet size of the emulsions was highly tunable, and ranged from 1 to 30 μm in diameter. The controllable droplet size along with the high colloidal stability of the Pickering emulsionswas harnessed to obtain single cell microencapsulation. Successful encapsulation of the conidia entomopathogenic fungus Metarhizium brunneum by the studied Pickering emulsions was confirmed via confocal laser scanning microscopy. The resulting systems were implemented to develop a novel biopesticide formulation for arthropod pest control. The conidia incorporated in the emulsions were applied to Ricinus communis leaves by spray assay. After drying of the emulsion, a silica-based honeycomb-like structure with an ordered hierarchical porosity is formed. This structure preserves the individual cell encapsulation. The successful single cell encapsulation has led to a high distribution of conidia cells on the leaves. The Pickering emulsion-based formulation exhibited significantly higher pest control activity against Spodoptera littoralis larvae compared to the control systems, thus making it a promising, cost-effective, innovative approach for tackling the pest control challenge.

Recent world events have demonstrated the critical need for facile and miniaturized bioremediation technologies for organophosphates (OPs). These compounds are among the most toxic substances synthesized to date and are used as pesticides and nerve agents. Biotechnological methods based on the use of organophosphate hydrolase (OPH) for detoxification of OPs have drawn significant attention. This work presents a new ‘one-pot’ methodology for a rapid and straightforward fabrication of enzymatically active carbon nanotube (CNT) paper for OP bioremediation. Carboxylated CNTs are ultrasonically dispersed in an aqueous surfactant solution followed by a microfiltration process to generate a paper-like membrane, which is assembled from entangled nanotubes. Herein, OPH conjugation to the CNTs is carried out by carbodiimide chemistry during the microfiltration process. Successful covalent immobilization of the enzyme onto the nanotube surface is confirmed by cryo-transmission electron microscopy and infrared spectroscopy. To study the potential of this platform for OP bioremediation, an aqueous solution of methyl paraoxon (used as a model OP) is filtered with the resulting OPH–CNT membranes. A significant decrease of methyl paraoxon concentration is achieved, which is ascribed to its in situ hydrolysis by the immobilized OPH during the filtration process. These thin membranes allow many subsequent filtration cycles to be performed, while maintaining their enzymatic activity, owing to the unique combination of the mechanically robust CNT scaffold and high OPH loading. This study presents a new generic approach for the design of bioactive paper-like scaffolds, which can be rationally tailored for a variety of applications.

Polymeric nanocomposites consist of nanoparticles imbedded in organic polymers, comprising a new class of materials. The combination of conducting nanoparticles and conducting polymers, described as hybrid electrically conducting nanocomposites, is a new emerging field. These materials may exhibit unprecedented properties, attractive for both the industry and academia. There is a variety of applications for conductive nanocomposites, i.e., sensors, actuators, touch screens, etc. The combination of conductive polymers with conductive carbon nanotubes has already shown some synergistic properties. The goal of the present review is to summarize the literature reporting work done on combining polyaniline (PANI), an electrically conductive polymer, with carbon nanotubes (CNT) including the authors’ work.

Poly-l-lactide-co-ε-caprolactone (PLCL) is a unique polymer containing both polylactic acid and poly-ε-caprolactone (PCL) chain units, and thus it has better flexible and biodegradable properties. Based on these unique properties of PLCL, we have developed balloons that are now widely used in treating major medical problems [Biomaterials2016,105, 109–116]. One of the most important considerations needed for balloons is to ensure that the material properties remain similar after undergoing ethylene oxide (EtO) or gamma (γ-) sterilization treatments. From the biotechnological point of view, we focused on analyzing the vital molecular properties of the PLCL material after sterilization, such as changes in crystallinity, molecular weight distributions (M_w, M_n, and polydispersity index), and inherent viscosity (η). Analysis of the data reveals that EtO sterilization does not engender any change in crystallinity, melting temperature (T_m), molecular weights, and η of the polymer. On the contrary, γ-radiations induce chain scission and consequential decrease of ∼33 and ∼15% in molecular weights and η values, respectively. Based on our observations, we recommend EtO sterilization instead of γ-radiation for PLCL. This ensures prolonged stability of the polymer against degradation in a biological environment, long-shelf life, and absolute assurance that balloon failures do not occur after implantation.