Plants are the greatest source of anticancer medicaments all over the world. The application of in vitro methods to plant tissue cultures allows increasing biomass proliferation and maximizing the productivity of secondary metabolites. Various in vitro techniques are proposed to intensify plant biomass cultures for anticancer metabolite production. Literature data indicate that plant biomass immobilization is one of the most efficient techniques to significantly increase biomass proliferation and the yield of secondary metabolite secretion. The application of polymeric-based scaffolds for plant biomass immobilization may be an easy and inexpensive way of supporting culture systems for hairy roots bioengineering.

The aim of the study was to quantitatively identify the influence of four various polymeric constructs on biomass proliferation and naphthoquinone derivative secretion in cultures of Rindera graeca hairy roots. Biomass was independently immobilized on polymeric constructs made of pure and certified polylactic acid (PLA), acrylonitrile styrene acrylate (ASA), acrylonitrile butadiene styrene (ABS), and nylon (N). Different shapes and surfaces of scaffolds were applied. As a reference system, a culture of non-immobilized biomass without any polymeric constructs was performed. The increases in the fresh biomass and naphthoquinone derivative concentration in culture systems were determined quantitatively.

The immobilization of hairy roots on PLA greatly increased fresh biomass, while immobilization on N had no significant impact on biomass proliferation. The application of ASA and ABS even decreased the level of fresh biomass in comparison to the reference culture system. The most effective in increasing proliferation was the polymeric scaffold made of PLA 90, which stands for an overhang angle in 3D printing. Naphthoquinone derivatives have been noticed only in the culture immobilized on a ball-shaped PLA. In other cultures, naphthoquinone derivative concentration did not reach the detection threshold.

Funding: This research was funded by the National Science Centre (NCN), Poland, grant no. 2021/41/N/ST8/00958.