A Scalable 3-D Printed Biological Assembly Technology

This paper presents a scalable biomolecular assembly on three-dimensional (3-D) electrodes enabled by electro-bioprinting (EBP). A highly uniform assembly of proteins - cysteine-modified Tobacco mosaic virus (TMV1cys) and glucose oxidase (GOx) - on micropillar array (μPA) electrodes is achieved, enabled by selective and sequential EBP of biological inks (biomolecule-containing aqueous media). The printing and assembly of the biomolecules (termed "print-assembly") on the 3-D surfaces is confirmed via SEM showing nanoscale "rod-like" structures corresponding to TMV1cys/GOx coating on EBP-processed surfaces. Colorimetric assays confirmed biological/enzymatic activity, where TMV1cys/GOx functionalization on μPAs significantly increase enzymatic reaction density compared to functionalized planar surfaces. Specifically, the reaction density per device foot-print has been enhanced by factors of 4 and 5.5, closely corresponding to the surface area enhancement factors derived from respective μPA geometries. This work demonstrates a highly scalable, efficient, and customizable biomolecular assembly method, providing numerous opportunities in developing biomaterial-integrated devices including biochemical sensors, bioenergy harvesters, and drug-delivery devices.