Harvesting specific plant metabolites from hairy root cultures using magnetized nanoparticles

AbstractPlant cell cultures are becoming a commercially valuable source of pharmaceuticalsparticularly those that are too complex for economical chemical synthesisFor example Phyton Biotechin Germanyhas achieved great commercial success by generating taxoids for Paclitaxel production in sterile plant cell bioreactorsHoweverthe efficiency of these systems is limited by the loss in viability of the slow growing plant cells associated with conventional extraction proceduresThe objective here is to develop a system that allows plant cells to be harvested repeatedly for high value pharmaceutical products without losing viabilityPhase I demonstrated that nanoparticles can be functionalized to enter plant cells and bind specific bioactive flavonoid metabolites before being extrudedand these metabolites recoveredall without loss of plant cell viabilityPhase II now aims to demonstrate that a similarbut more selectiveapproach can be used to harvest higher value pharmaceuticals from plant cellsi eproof of applicationThe most valuable types of metabolite currently produced from plants include isoflavonesalkaloids and monoclonal antibodiesthe latter from transgenic plantsPhase II aims to show that each of these types of product can be harvested from plant cells by their selective binding to nanoparticles on which specific oligopeptides have been conjugatedEach product example is relevant to anti cancer therapeuticsThe first is the phytoestrogenliquiritigeninwhich is a selective agonist of the estrogen receptorER beta that should reduce risk of breast cancer post menopauseThis flavanone will be harvested from overproducing mutant cultures of licorice root by selective binding to the ERbeta ligand binding oligopeptide conjugated to nanoparticlesThe second example is to nanoharvest the chemotherapeutic vinca alkaloidscurrently extracted from intact plant material by Eli Lillyfrom overproducing mutant cultures of Catharanthus roseusThese alkaloids will be harvested by affinity to nanoparticles bearing oligopeptides representing their binding sites on human tubulinThese two examples are natural metabolitesbut the most commercially important application of this technology may be to harvest foreign polypeptidesi ebiologicssuch as antibodiesfrom transgenic plant cellsHere the example will be the harvesting from transgenic tobacco cell cultures of a monoclonal antibodymAbHdirected against tumor cellsSelective binding will be achieved using nanoparticles in which an oligopeptide mimicking the antibody binding site on the antigen has been conjugated to the surfaceIn all of these examples the objective is to show that nanoparticles can repeatedly remove the desired commercial product without loss of plant cell viabilityThis will reducedown timeand could also reduceresponse timefor example the urgent requirement for antibodies or vaccines in an outbreak of diseaseIn additionseparation of product by affinity to an oligopeptide binding site means that the harvested products will be simultaneously semi purifiedPhase II should demonstrate proof of application for the nanoparticle harvesting technology as applied to high value anti cancer pharmaceuticalsThe applicants will then move toward commercialization in partnership with identified pharmaceutical and biotechnology companies in the US and Europesee Commercialization Plan