CAREER: Developing Ultrasound-Programmable 3D-Printed Biomaterials for Spatiotemporal Control of Gene Delivery

NON-TECHNICAL SUMMARY

Building 3D structures outside the body that mimic biological tissue is critical for studying how cells interact with each other in their native environment, and for understanding how these processes change in disease. Utilizing printable bioink materials combined with cells, 3D bioprinting offers an unprecedented ability to build cell-containing 3D structures that replicate the complex multicellular patterns and geometries of native tissue.

A key approach to studying these cell interactions is by introducing new genetic material to cells to change their behavior in a defined way and controlling when and where the cells receive these genetic instructions. However, it is challenging to achieve this control in 3D printed structures using current approaches, as the 3D construct presents a physical barrier to gene delivery.

Addressing this challenge, this project will develop a new 3D printable bioink that allows deep-penetrating ultrasound to trigger the delivery of genetic material to cells. The ultrasound waves can be focused to small spots within the 3D bioprinted structure to create desired patterns of gene delivery by activating embedded ultrasound-responsive particles.

This project will produce new fundamental knowledge about how embedded ultrasound-responsive particles affect the material properties of the printable bioinks and will determine how bioink material properties affect ultrasound-induced particle activation. These novel materials will allow researchers to study new aspects of cell behavior in tissue-relevant 3D geometries.

This project will also enable new materials for use in regenerative medicine applications where remote genetic manipulation of cells at specific times after implantation can instruct cellular communication and improve healing of damaged tissue. This project will develop educational activities that engage underrepresented students at multiple levels in 3D bioprinting and responsive biomaterials research, providing mentorship opportunities and fostering retention in STEM.

Broader reach of this work will also be facilitated through development of interactive workshops to introduce 3D printing research to middle and high school students, as well as accessible 3D biofabrication modules to promote public interest in bioprinting and responsive biomaterials. TECHNICAL SUMMARY

3D bioprinting is a major advance allowing direct formation of cell scaffold structures that closely mimic the multi-component architecture of native tissues. However, it is a challenge to apply the critically important tool of genetic manipulation to influence cell behaviors within 3D scaffolds with temporal and spatial control because scaffolds hinder diffusion of traditional transfection vectors.

Overcoming diffusional barriers to enable genetic control over subsets of cells within scaffolds is essential for developing new biomaterials to replicate and perturb genetic expression patterns found in native tissue. This project focuses on fundamental development and characterization of a new class of biomaterials that combine a novel ultrasound-responsive 3D scaffold cell culture platform with 3D-printable bioinks to enable remote spatiotemporal control over genetic manipulation of embedded cells.

The three main objectives are to: (1) understand how embedded ultrasound-responsive particles affect scaffold material properties, (2) determine how bioink material properties affect ultrasound-induced particle cavitation, and (3) characterize ultrasound-patterned DNA delivery to cells within multicellular 3D-bioprinted scaffolds. Multi-level integrated education activities will create research and mentoring opportunities for underrepresented undergraduate and graduate students in new stimuli-responsive bioink research, supporting student engagement and retention.

Outreach and education efforts will also include interactive activities to introduce 3D printing technology to students at the middle and high school level, and dissemination of accessible 3D biofabrication education modules as a resource to increase public knowledge and interest in biomaterials.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.