Skip to main content
2024 BMES Annual Meeting Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.
Back

Biomaterials

Biomaterials - Poster Session E

Poster O3 - Hydrogel Tissue Expanders for Stimulating Facial Growth in Congenital Microphthalmia Patients

Saturday, October 26, 2024
10:00 AM – 11:00 AM EST
Location: Exhibit Hall E, F & G

Introduction:  Microphthalmia and anophthalmia, conditions where a child is born with at least one abnormally small or missing eyeball, puts the afflicted at risk for abnormal facial development. Absence of an eyeball hinders normal orbital and facial growth, which leads to deformities that impede social interactions. Early intervention is critical to maintain symmetrical development and enable implantation of a permanent prosthetic later in life. Currently, the standard of care is a self-inflating osmotic expander to guide bone and soft tissue expansion. A large setback in the treatment of children born with this congenital disease is the loss of the gold standard product due to the bankruptcy of the sole supplier. Technical challenges with these devices include a rapid rate of initial expansion, which can lead to inflammation of the surrounding tissue. Long term use of a single device also results in biofilm formation. The goal of this work is to identify a biomaterial formulation that promotes sufficient soft tissue expansion while mitigating the disadvantages of the product currently used in the clinic.

Materials and

Methods:  Hydrogels with varying ratios of methyl methacrylate, n-vinyl pyrrolidone (NVP), and crosslinker were synthesized via bulk free radical polymerization using azobisisobutyronitrile (AIBN) as a thermal initiator. A 4 mm biopsy punch was used to punch uniform cylinders from the hydrated hydrogel sheet. Saponification of the gels in 3M NaOH occurred over 24, 48, or 72 hours to generate an ionic hydrogel.

Swelling studies: Dry weights of all hydrogels were recorded. Gels were incubated in 0.9% NaCl (w/v, in DI water) at 37C under constant shaking. At designated timepoints, gels were blotted dry and masses were recorded. For swelling of gels with interpenetrating networks, gels were incubated in PBS with lysozyme (2 mg/mL). Swelling ratio was calculated as followed: Swelling ratio = (hydrated mass – dry mass)/dry mass

Results, Conclusions, and Discussions: Swelling potential was controlled by both monomer percentage and percent ionization. Water uptake as measured by mass change over time reached a plateau at ~2 hours after initial hydration, and percent mass change at equilibrium ranged from 150-800%. Formulations containing 80% NVP demonstrated a swelling ratio comparable to the industry standard. Swelling ratio could be tuned even further by modulating percentage of initiator and crosslinker. Preliminary data from subcutaneous implantation of the hydrogels in rats demonstrate translation of composition-driven swelling behavior from in vitro to in vivo, thus validating the utility of these hydrogels as tissue expanders for a range of applications.

Acknowledgements (Optional):