A Multi-Criteria Assessment Strategy for 3D Printed Porous Polyetheretherketone (PEEK) Patient-Specific Implants for Orbital Wall Reconstruction.

Pure orbital blowout fractures occur within the confines of the internal orbital wall. Restoration of orbital form and volume is paramount to prevent functional and esthetic impairment. The anatomical peculiarity of the orbit has encouraged surgeons to develop implants with customized features to restore its architecture. This has resulted in worldwide clinical demand for patient-specific implants (PSIs) designed to fit precisely in the patient's unique anatomy. Material extrusion or Fused filament fabrication (FFF) three-dimensional (3D) printing technology has enabled the fabrication of implant-grade polymers such as Polyetheretherketone (PEEK), paving the way for a more sophisticated generation of biomaterials. This study evaluates the FFF 3D printed PEEK orbital mesh customized implants with a metric considering the relevant design, biomechanical, and morphological parameters. The performance of the implants is studied as a function of varying thicknesses and porous design constructs through a finite element (FE) based computational model and a decision matrix based statistical approach. The maximum stress values achieved in our results predict the high durability of the implants, and the maximum deformation values were under one-tenth of a millimeter (mm) domain in all the implant profile configurations. The circular patterned implant (0.9 mm) had the best performance score. The study demonstrates that compounding multi-design computational analysis with 3D printing can be beneficial for the optimal restoration of the orbital floor.

Intraspecific and interspecific interactions among proteins regulating exopolysaccharide synthesis in Streptococcus thermophilus, Streptococcus iniae, and Lactococcus lactis subsp. cremoris and the assessment of potential lateral gene transfer.

Using the yeast two-hybrid system, intraspecific protein interactions were detected in Streptococcus iniae and Lactococcus lactis subsp. cremoris between the transmembrane activation protein (CpsC and EpsA, respectively) and the protein tyrosine kinase (CpsD and EpsB, respectively), between two protein tyrosine kinases, and between the protein tyrosine kinase and the phosphotyrosine phosphatase (CpsB and EpsC, respectively). For each of these intraspecific interactions, interspecific interactions were also detected when one protein was from S. iniae and the other was from Streptococcus thermophilus . Interactions were also observed between two protein tyrosine kinases when one protein was from either of the Streptococcus species and the other from L. lactis subsp. cremoris. The results and sequence comparisons performed in this study support the conclusion that interactions among the components of the tyrosine kinase - phosphatase regulatory system are conserved in the order Lactobacillales and that interspecific genetic exchanges of the genes that encode these proteins have the potential to form functional recombinants. A better understanding of intraspecific and interspecific protein interactions involved in regulating exopolysaccharide biosynthesis may facilitate construction of improved strains for industrial uses as well as identification of factors needed to form functional regulatory complexes in naturally occurring recombinants.