title: Binder-jetting 3D printing and alloy development of new biodegradable Fe-Mn-Ca/Mg alloys.
abstract: 3D printing of various biomaterials including titanium and stainless steel has been studied for treating patients with cranio-maxillofacial bone defect. The potential long term complications with use of inert biometals have opened the opportunities for use of biodegradable metals in the clinical arena. The authors previously reported that binder-jet 3D printing technique enhanced the degradation rates of biodegradable Fe-Mn alloy by creating engineered micropores rendering the system attractive as biodegradable implantable devices. In the present study, the authors employed CALPHAD modeling to systematically study and modify the Fe-Mn alloy composition to achieve enhanced degradation rates. Accordingly, Ca and Mg addition to Fe-35wt% Mn solid solution predicted increase in degradation rates. In order to validate the CALPHAD results, Fe - (35-y)wt% Mn - ywt% X (X=Ca, Mg, and y=0, 1, 2) were synthesized by using high energy mechanical alloying (HEMA). Sintered pellets of Fe-Mn-Ca and Fe-Mn-Mg were then subjected to potentiodynamic polarization (PDP) and live/dead cell viability tests. Sintered pellets of Fe-Mn, Fe-Mn-Ca, and Fe-Mn-Mg also exhibited MC3T3 murine pre-osteoblast cells viability in the live/dead assay results. Fe-Mn and Fe-Mn-1Ca were thus accordingly selected for 3D printing and the results further confirmed enhanced degradation of Ca addition to 3D printed constructs validating the theoretical and alloy development studies. Live/dead and MTT cell viability results also confirmed good cytocompatibility of the 3D-printed Fe-Mn and Fe-Mn-1Ca constructs.
  
  
  
  Bone grafting is widely used for the treatment of cranio-maxillofacial bone injuries. 3D printing of biodegradable Fe alloy is anticipated to be advantageous over current bone grafting techniques. 3D printing offers the fabrication of precise and tailored bone grafts to fit the patient specific bone defect needs. Biodegradable Fe alloy is a good candidate for 3D printing synthetic grafts to regenerate bone tissue without eliciting complications. CALPHAD theoretical models were used to develop new Fe-Mn-Ca/Mg alloys to enhance the degradation rates of traditional Fe-Mn alloys. In vitro experimental results also showed enhanced degradation rates and good cytocompatibility of sintered Fe-Mn-Ca/Mg compacts. 3D printing of Fe-Mn and Fe-Mn-1Ca alloys further demonstrated their feasibility as potentially viable bone grafts for the future.
authors: Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, United States.
authors: Daeho
authors: D
authors: Hong
authors: Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, United States.
authors: Da-Tren
authors: DT
authors: Chou
authors: Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, United States.
authors: Oleg I
authors: OI
authors: Velikokhatnyi
authors: Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, United States.
authors: Abhijit
authors: A
authors: Roy
authors: Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, United States.
authors: Boeun
authors: B
authors: Lee
authors: Department of Engineering, Robert Morris University, Moon, PA 15108, United States.
authors: Isaac
authors: I
authors: Swink
authors: Department of Mechanical Engineering, Ort Braude College, Karmiel, Israel.
authors: Ilona
authors: I
authors: Issaev
authors: ExOne Company, Irwin, PA 15642, United States.
authors: Howard A
authors: HA
authors: Kuhn
authors: Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, United States; Department of Chemical and Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, United States; Department of Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, United States. Electronic address: pkumta@pitt.edu.
authors: Prashant N
authors: PN
authors: Kumta
mesh_terms: D000497:Alloys / Q000737:chemistry*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D002460:Cell Line; D002470:Cell Survival; D003343:Corrosion; D004560:Electricity; D055664:Electrochemical Techniques; D005453:Fluorescence; D007501:Iron / Q000737:chemistry; D008422:Materials Testing; D008670:Metals / Q000737:chemistry*; D051379:Mice; D008962:Models, Theoretical; D010006:Osteoblasts / Q000166:cytology / Q000648:ultrastructure; D016062:Porosity; D011208:Powders; D066330:Printing, Three-Dimensional; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D014961:X-Ray Diffraction
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D008670:Metals; D011208:Powders; D007501:Iron
keywords: 3D printing; Biodegradable metal; Bone defect; Fe-Mn alloy; Medical scaffold