Biogenic Polymers for Congenital Cardiac Surgery: In Vitro Durability Testing

Currently available materials in congenital cardiac surgery (CCS) are far from optimal because they do not facilitate growth, remodelling, or renewal, resulting in poorer long-term outcomes due to material-related limitations. Bacterial cellulose (BC), a biogenic polymer-based material produced by Acetobacter xylinum, has emerged as a promising alternative exhibiting excellent bio- and haemocompatibility. This study aimed to develop BC specifically for application in CCS by modifying culturing conditions to enhance its biomechanical resilience.

Bacterial cellulose was produced according to a standard protocol, and its biomechanical properties were evaluated using inflation pressure testing, thickness measurement, and uniaxial tensile testing. To improve these characteristics, 2 modifications, a change in the growth media composition and an extended incubation time, were implemented and subsequently evaluated in 5 further test series. The long-term durability of BC patches was assessed in a fatigue tester for 20 ± 0.5 million cycles, and potential structural damage was investigated using scanning electron microscopy.

Utilizing the 2 modifications, BC patches demonstrated a capability to reach and maintain pressures exceeding 1000 mm Hg with a durability of 100% (n = 24), compared to the standard 20.8% (n = 24) at 500 mm Hg. The maximum tensile strength was enhanced from 0.311 ± 0.057 megapascal (MPa) to 0.986 ± 0.397 MPa (P < .0001), with a thickness of 3.89 ± 0.95 mm (P < .0001). In the long-term durability testing, patches endured durations equalling 6 months without failure while retaining structural integrity.

The potential of BC for use in CCS was demonstrated by enhancing its biomechanical properties through culturing modifications, warranting further investigation and development of the biomaterial.