Abstract
Evaluation of different biomaterials is being performed with various methods trying to simulate the closest hostile-like in vitro environments. However the complexity of the conditions usually limits practically feasible combination of most relevant chemical, biological, biomechanical parameters in one single test. Many biomaterials and tissue engineering developments rely on high-throughput screening to multiply number of specimens and thus to gather sufficient data. The price to be paid for these methods is limited number of physical readouts, increased inter-specimens scatter, and unavoidable spatial constrains driving the conditions away of the clinical scenarios. For orthopaedic biomaterials this is of a particular concern, as implantation site conditions cannot be squeezed too much without lost of natural-mimicking stimuli.
Here we are presenting another approach based on high-output screening of biomaterials, which is based on the strategy of raising the number of readouts obtainable from every specimen at more clinically-relevant conditions. On the contrary to common methods like ISO 10993 or simplified biomechanical tests, the biomaterials enhanced simulation testing (BEST) evaluates specimens without pre-selected biomaterial model, assessing the whole specimen as would happen in the implantation site. Besides reducing the risk of improper conclusions caused by wrong material model choice, the data processing with non-local method intrinsically includes the test history bypassing common challenges usually seen with hereditary integration. For properly designed experiment, readouts might include invariant moduli, viscous stiffness, fluidity, fluid permittivity and diffusivity (without need for pressure-driven separate tests), fluid source, effective channel size, and swelling pressure (if swelling is present) in addition to conventional biomechanical parameters.
New solutions in advanced and consistent evaluations for biomaterials allow better risks control, shorten lead development time and costs, and compliant with 3R-strategy (2010/63/EC) and new regulatory requirements (2012/0266/COD in EU and FY2017 regulatory priorities by FDA). The approach shown is able to combine scientifically based tests with multi-purpose protocols to secure patient safety by screening of biomaterials under proper conditions.
The authors thank Finnish Agency for Innovations (Tekes) for providing partial financial support.
