Dextran is widely exploited in medical products and as a component of drug-delivering nanoparticles (NPs). Here, we tested whether dextran can serve as the main substrate of NPs and form a stable backbone. We tested dextrans with several molecular masses under several synthesis conditions to optimize NP stability. The analysis of the obtained nanoparticles showed that dextran NPs that were synthesized from 70 kDa dextran with a 5% degree of oxidation of the polysaccharide chain and 50% substitution with dodecylamine formed a NP backbone composed of modified dextran subunits, the mean diameter of which in an aqueous environment was around 100 nm. Dextran NPs could be stored in a dry state and reassembled in water. Moreover, we found that different chemical moieties (e.g., drugs such as doxorubicin) can be attached to the dextran NPs via a pH-dependent bond that allows release of the drug with lowering pH. We conclude that dextran NPs are a promising nano drug carrier.

Deposition of aerosol particles during sampling and transport through tubes has been studied by considering the effect of diffusion, sedimentation, inertial impaction and turbulent deposition. The pertinent equations are summarized and graphs presented showing particle deposition as a function of particle size, tube diameter and length, and flowrate. The influence of electric charge on particle deposition has been studied by measuring the penetration of monodisperse. charged aerosols through metal and plastic tubings. The result has been expressed in terms of a mean surface electric field on the plastic tubing surfaces. For Polyflo® and Teflon®, the mean surface electric field has been found to be in the vicinity of 50–200 V cm ⁻¹ and, for Tygon®, essentially zero. The surface electric charge on several commonly used filters has also been measured and the influence of this charge on particle deposition in the filter-housing during sampling has been studied.