The development of the iFixInk^TM system to treat corneal injuries

Abstract

Purpose : Human platelet lysate (hPL) has been shown to encourage proliferation and migration in immortalised corneal epithelial cells (HCE-T). We aimed to develop a novel, xenogeneic-free BioInk (iFixInk^TM) that is transparent, biocompatible, biodegradable and bioprintable, utilising the therapeutic benefits of hPL in a 3-dimensional matrix that mimics the native cornea.

Methods : IncuCyte^® live cell analysis was used to measure proliferation of P23 HCE-T cells in iFixInk^TM seeded in a 96 well plate (n=6) over 7 days. A rheometer was used to measure the storage (G’) and loss (G”) moduli over a time-sweep oscillation of 1Hz. Viscosity across a shear rate ramp between 0.1s^-1 and 100s^-1 after a 2-minute setting time was also quantified. Mean transmittance of light was measured across the visible spectrum. Pig corneas were perforated with a needle (diameter = 1mm) and sealed with iFixInk^TM. Gelation time and line resolution printing were also tested.

Results : HCE-T cells were able to reach confluence over a period of 7 days (92.96±1.07%) (Fig 1). G’ (10.28±0.02Pa) was significantly higher than G” (0.56±0.01Pa) across the time-sweep oscillation suggesting extrusion bioprinting compatibility (Fig 2A) and this gelation process is temperature independent. Mean viscosity was decreased in a non-Newtonian trend across an increasing shear-rate demonstrating shear-thinning properties and further bioprinting compatibility (Fig 2B). Mean transmittance exceeded 97% through the visible spectrum demonstrating transparency (Fig 2C,2D). iFixInk^TM was able to successfully create a water-tight seal. Gelation time was under 5 minutes and printing resolution compatible for use in corneal-sized injuries.

Conclusions : We have successfully created a novel BioInk that is biocompatible, biodegradable, transparent and bioprinteable via extrusion that has the potential to treat corneal injuries such as abrasions and ulceration.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

Figure 1. Mean confluence as a percentage over 7 days for HCE-T cells grown in the iFixInk^TM ± SEM (n=6)

 

Figure 2. Mechanical properties of the iFixInk^TM (n=3) after 2-minute setting time ± SEM A. G’ and G” moduli in Pascals over a time-sweep oscillation of 1Hz B. Mean viscosity in Pascal seconds over a shear rate between 0.1s^-1 and 100s^-1 C. Mean transmittance of wavelengths in the visible spectrum through a 2mm thickness of the iFixInk^TM (%). D. Example of iFixInk^TM