Printzyme: a customizable 3D printed device for enzymatic removal of drugs in water

The unintentional entry of drugs into the world’s water supplies is a major concern for both environmental equilibrium and human health. Worryingly, drugs have been identified in almost all types of aquatic compartments, including ground water, sea water, and drinking water, generally at concentrations of ng to µg/L (though cases exceeding 100 mg/L are not uncommon). Analgesics, antibiotics, lipid-lowering drugs, and oestrogens are globally recognised as key water contaminants, with many listed on the European watch list. Several methods have been proposed for the removal of drugs from aqueous systems (such as biofiltration, reverse osmosis, and sludge processes), however none are ideal due to low drug removal rates, high costs, and the requirement for large equipment.

To address this shortfall, we recently designed, fabricated, and validated Printzyme, a 3D printed hydrogel system loaded with laccase sourced from Trametes Versicolor. The laccase enzyme is widely recognised for its drug-degrading properties through biocatalysis, and its immobilization within Printzyme enables its use in a process-specific and reusable manner. Because Printzyme structures can be designed and printed into an endless number of morphologies, the system is applicable for use in a wide number of applications. For example, Printzymes could be fabricated to fit into unique water pipe structures, afforded high resolution due to the precision of stereolithographic 3D printing.

Our results showed that laccase immobilization within Printzyme significantly protected enzyme activity at extremes of pH and temperature compared to free laccase. Moreover, individual Printzymes retained their biocatalytic activity for at least 18 unique cycles of use. When applied to drug removal, Printzymes removed > 90% of diclofenac and ethinyl oestradiol from aqueous solution in 24 and 2 hours, respectively. This work showcases the Printzyme technology as a cost-efficient, customizable, and sustainable method for tackling the world’s water pollution crisis.