(M1430-03-15) Development of 3D Printable Inks for Protein Delivery

Purpose: The purpose of this study is to develop a novel ink formulation for 3D printing of proteins without compromising its activity during and after printing. Identifying a suitable ink, that possess 3D printing properties, can potentially increase the 3D pharmaceutical use of proteins and enzymes.

Methods: The β-galactosidase (β-gal), a model enzyme, was used. Different β-gal containing constructs were printed from ink formulation composed mainly of polymer A and sugar S1 using 3D-microextrusion technique. The β-gal (15 U/mL) was incorporated in the polymer A (30% w/v) during the preparation step and printed into 3D square-shape constructs with different sugar concentrations (2-10%, w/v). In addition, the effect of construct thickness (i.e., 2- and 4-layers) on β-gal activity was evaluated. Spectrophotometric assay was performed to measure the activity of the β-gal during and after printing.

Results: 3D printing of β-gal in polymer A has demonstrated good printing properties such as viscosity and printing fidelity. All the 3D printed constructs, with different sugar concentrations used, showed a comparable level of the β-activity to the control (i.e., β-gal in phosphate-buffer saline, PBS, pH 7.4, 10 mM). However, the β-gal activity started to decline after 24 h in the printed construct containing 2% and 5% of sugar S1 whereas the printed construct containing 10% of sugar S1 maintained the β-gal activity for 72 h (Fig.1). The 3D printing of 4-layer construct preserved the β-gal activity longer than the 2-layer construct, most likely due to the slower rate of water evaporation.

Conclusion: Suitable 3D printable ink compositions were developed and used to print different constructs containing β-gal without compromising its activity. The ink sugar concentration and 3D construct design have influence on the activity of β-gal after printing. It is expected that the ink composition and printing design will improve the application of 3D printing in protein and enzyme delivery.

Acknowledgements: The authors extend their appreciation to the Deputyship for Research & Innovation, Ministry of Education in Saudi Arabia for funding this work

Figure 1. Effect of sugar S1 concentration on β-gal activity. β-gal containing square constructs (15 U/mL) were printed using inks composed of polymer A and different sugar S1 concentrations (2%, 5%, 10% w/v). After printing, the samples were stored at room temperature and the β-gal activity was measured at different time points (24, 48, 72 h). β-gal in PBS was used as a control. All measurements were reported as mean ± S.D. (n = 3).