Chitosan/TPP and chitosan/TPP-hyaluronic acid nanoparticles: systematic optimisation of the preparative process and preliminary biological evaluation.

PURPOSE: Chitosan is one of the most sought-after components for designing nanoparticles for drug delivery applications. However, despite the large number of studies, reproducibility is often an issue; generally more attention should be focused on purity and precise characterization of the starting material, as well as on the development of robust preparative procedures. METHODS: Using a rational experimental design, we have studied the influence of a number of orthogonal factors (pH, concentrations, ratios of components, different methods of mixing) in the preparation of chitosan/triphosphate (TPP) nanoparticles and in their coating with hyaluronic acid (HA), aiming at the minimisation of size polydispersity, the maximisation of zeta potential and long-term stability, and at the control over average nanoparticle size. RESULTS AND CONCLUSION: Three optimised nanoparticles have been developed (two uncoated and one HA-coated) and their toxicity on fibroblasts and macrophages has been evaluated: experiments showed the beneficial character of HA-coating in the reduction of toxicity (IC50 raised from 0.7-0.8 mg/mL to 1.8 mg/mL) and suggested that the uncoated chitosan/TPP nanoparticles had toxic effects following internalisation rather than membrane disruption.

Uptake of nicotine from suspension culture of Nicotiana tabacum by molecularly imprinted polymers.

OBJECTIVES: The aim was to use molecularly imprinted polymers (MIPs) for the selective recovery of nicotine in plant cell cultures. MIPs can selectively uptake nicotine from suspension cultures of N. tabacum, and therefore may be useful for improving levels of secondary metabolites in plant cell cultures. METHODS: Suspension cultures of N. tabacum were initiated from callus and maintained in liquid Murashige and Skoog (MS) media containing 3% w/v sucrose, 0.1 mg/l alpha-naphthaleneacetic acid acid (NAA) and 0.25 mg/l kinetin. Tween 80 at 1% was used for permeabilisation of cell cultures. Pre-weighed XAD-2 and two types of synthesized polymers, MIPs (A and B with one and two functional monomers, respectively) and corresponding non-imprinted polymers (NIPs), A and B, were introduced aseptically into the permeabilised suspension cultures of N. tabacum, the nicotine contents of polymers were determined by gas chromatography and the adsorption yield of polymers were determined. KEY FINDINGS: Cell cultures of N. tabacum accumulated nicotine alkaloid intracellularly in varying levels, 6.8-14.9 mg/l fresh weight. MIPs were able to uptake 50-70% of released nicotine in suspension cultures of N. tabacum, whereas XAD-2 recovered only 30-40%. The total levels of accumulated nicotine were enhanced up to 20 mg/l by simultaneous use of Tween 80 and MIPs. CONCLUSIONS: The findings indicate the potential use of MIPs to uptake nicotine from suspension cultures of N. tabacum, and increase productivity of secondary metabolites in plant cell cultures.