3D-Printed Microinjection Needle Arrays via a Hybrid DLP-Direct Laser Writing Strategy

Sunandita Sarker; Adira Colton; Ziteng Wen; Xin Xu; Metecan Erdi; Anthony Jones; Peter Kofinas; Eleonora Tubaldi; Piotr Walczak; Miroslaw Janowski; Yajie Liang; Ryan D Sochol

doi:10.1002/admt.202201641

3D-Printed Microinjection Needle Arrays via a Hybrid DLP-Direct Laser Writing Strategy

Adv Mater Technol. 2023 Mar 10;8(5):2201641. doi: 10.1002/admt.202201641. Epub 2023 Feb 5.

Authors

Affiliations

¹ Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA; Maryland Robotics Center, University of Maryland, College Park, MD 20742, USA; Institute for Systems Research, University of Maryland, College Park, MD 20742, USA.
² Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA.
³ Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742, USA.
⁴ Program in Image Guided Neurointerventions, Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
⁵ Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA; Maryland Robotics Center, University of Maryland, College Park, MD 20742, USA; Institute for Systems Research, University of Maryland, College Park, MD 20742, USA; Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA; Robert E. Fischell Institute for Biomedical Devices, University of Maryland, College Park, MD 20742, USA.

Abstract

Microinjection protocols are ubiquitous throughout biomedical fields, with hollow microneedle arrays (MNAs) offering distinctive benefits in both research and clinical settings. Unfortunately, manufacturing-associated barriers remain a critical impediment to emerging applications that demand high-density arrays of hollow, high-aspect-ratio microneedles. To address such challenges, here, a hybrid additive manufacturing approach that combines digital light processing (DLP) 3D printing with "ex situ direct laser writing (esDLW)" is presented to enable new classes of MNAs for fluidic microinjections. Experimental results for esDLW-based 3D printing of arrays of high-aspect-ratio microneedles-with 30 μm inner diameters, 50 μm outer diameters, and 550 μm heights, and arrayed with 100 μm needle-to-needle spacing-directly onto DLP-printed capillaries reveal uncompromised fluidic integrity at the MNA-capillary interface during microfluidic cyclic burst-pressure testing for input pressures in excess of 250 kPa (n = 100 cycles). Ex vivo experiments perform using excised mouse brains reveal that the MNAs not only physically withstand penetration into and retraction from brain tissue but also yield effective and distributed microinjection of surrogate fluids and nanoparticle suspensions directly into the brains. In combination, the results suggest that the presented strategy for fabricating high-aspect-ratio, high-density, hollow MNAs could hold unique promise for biomedical microinjection applications.

Keywords: 3D printing; additive manufacturing; digital light processing; direct laser writing; microneedles.

Abstract

Grants and funding