3D microprinting-enabled microinjection needle arrays for enhanced therapeutics delivery into the brain

PROJECT SUMMARY Microinjection technologies underlie many research and clinical applications that require gene and cell delivery, including studies and emerging treatments of neurological conditions (e.g., neurodegenerative diseases, traumatic brain injury, and cancer). Unfortunately, challenges associated with the microinjection tools by which the viral vectors and cells inherent in these applications are delivered into brain tissues remain major barriers in these rapidly growing fields. Although widely used, the currently used industry standard needles (ISNs) comprise one needle with a single output port at the tip and are associated with a variety of validated customer pain points. In particular, (1) the physical size of therapeutics such as lentiviral particles (80–100 nm) and stem cells (rt10 μm) restricts ISN-mediated delivery into a single injection site inherently restricts the effective coverage range; (2) the single injection site for ISNs can also result in inhomogeneous distributions of delivered therapeutics, which can be detrimental to efficacy; and (3) the shape and size of ISNs can lead to brain tissue injury. Consequently, alternative, novel microinjection tools for both gene and cell delivery are in critical demand. The objective of this proposal is to develop an entirely new class of microneedle arrays (MNAs) that can be realized to simultaneously address all three aforementioned pain points of ISNs. The working hypothesis is that the minimal viable product (MVP) will transform microinjection outcomes via unparalleled versatility in realizing geometrically sophisticated MNAs innovations, improve the efficacy of delivering therapeutics to the brain and reducing microinjection-associated tissue damage. Preliminary studies demonstrated the ability of 3D microprinting-enabled microneedle arrays (MNAs) delivery strategy to penetrate and deliver microfluidic payloads into mouse brains. In addition, 3D-printed multi-side-port microneedles showed reduced penetration and retrieval-associated damage to zebrafish embryos during microinjection protocols. This proposal will examine the efficacy of this innovation to enhance fundamental performance metrics underlying both gene and cell delivery into brain tissue. To effectively accomplish this goal, we will: 1) establish and characterize MNA additive manufacturing protocols for novel 3D microneedle designs, 2) assess microfluidic and cell delivery efficacy of our innovative delivery strategy versus ISNs in vitro, and 3) evaluate gene and stem cell delivery into mouse brains mediated by our MNA innovation versus ISNs in vivo. This proposal to prototype MNA MVPs that improve penetration, injection, and retrieval efficacy versus ISNs bridges an important need in the biomedical industry, which will positively impact foundational human health-related research and medical applications.