Bio

Professional Education


  • Doctor of Philosophy, University of Waterloo (2011)
  • Master of Science, Iran Univ Of Science And Technology (2006)
  • Bachelor of Science, Iran Univ Of Science And Technology (2004)

Stanford Advisors


Patents


  • Yaser Shanjani. "Canada Patent PCT Patent, PCT/CA2014/050028, 77051W-90 WO Systems and methods for additive manufacturing of heterogeneous porous structures and structures made therefrom", Jan 17, 2014
  • Yaser Shanjani. "Iran Patent Reg. Off. for Com. and Ind. Prop., No. 44998 Polymeric Coating of Micro-Scale Metal Powder Particles through Super-Saturation Drawning-Out Technique", Jan 1, 2008
  • Yaser Shanjani. "Iran Patent Reg. Off. for Com. and Ind. Prop., No.44998 Polymeric coater of metal powder particles by vertical and tilted vibration technique", Jan 1, 2008
  • Yaser Shanjani. "Iran Patent Reg. Off. for Com. and Ind. Prop., No.29798 Rapid Prototyping with Electrical Discharge", Apr 1, 2004
  • Yaser Shanjani. "Iran Patent Reg. Off. for Com. and Ind. Prop., No.30762 Multipoint Plasma Arc Control System in SEDS", Apr 1, 2004
  • "Iran Patent Reg. Off. for Com. and Ind. Prop., No.30763 High Frequency Selective Electrical Discharge Sintering", Apr 1, 2004
  • Yaser Shanjani. "Iran Patent Reg. Off. for Com. and Ind. Prop., No.30764 Powder Feeding System with Rotary Mechanism in Selective Electrical Discharge Sintering", Apr 1, 2004

Research & Scholarship

Projects


  • Additive manufacturing/3D printing of prevascularized scaffold for regenerative medicine applications, Stanford Univeristy (9/1/2012)

    Location

    Stanford. CA

  • Spatiotemporal distribution of bioagents across tissue engineering scaffolds for regenerative medicine applications (9/1/2012)

    Location

    Stanford. CA

Lab Affiliations


Publications

Journal Articles


  • Porous calcium polyphosphate bone substitutes: Additive manufacturing versus conventional gravity sinter processing-Effect on structure and mechanical properties. Journal of biomedical materials research. Part B, Applied biomaterials Hu, Y., Shanjani, Y., Toyserkani, E., Grynpas, M., Wang, R., Pilliar, R. 2014; 102 (2): 274-283

    Abstract

    Porous calcium polyphosphate (CPP) structures proposed as bone-substitute implants and made by sintering CPP powders to form bending test samples of approximately 35 vol % porosity were machined from preformed blocks made either by additive manufacturing (AM) or conventional gravity sintering (CS) methods and the structure and mechanical characteristics of samples so made were compared. AM-made samples displayed higher bending strengths (≈1.2-1.4 times greater than CS-made samples), whereas elastic constant (i.e., effective elastic modulus of the porous structures) that is determined by material elastic modulus and structural geometry of the samples was ≈1.9-2.3 times greater for AM-made samples. X-ray diffraction analysis showed that samples made by either method displayed the same crystal structure forming β-CPP after sinter annealing. The material elastic modulus, E, determined using nanoindentation tests also showed the same value for both sample types (i.e., E ≈ 64 GPa). Examination of the porous structures indicated that significantly larger sinter necks resulted in the AM-made samples which presumably resulted in the higher mechanical properties. The development of mechanical properties was attributed to the different sinter anneal procedures required to make 35 vol % porous samples by the two methods. A primary objective of the present study, in addition to reporting on bending strength and sample stiffness (elastic constant) characteristics, was to determine why the two processes resulted in the observed mechanical property differences for samples of equivalent volume percentage of porosity. An understanding of the fundamental reason(s) for the observed effect is considered important for developing improved processes for preparation of porous CPP implants as bone substitutes for use in high load-bearing skeletal sites.

    View details for DOI 10.1002/jbm.b.33005

    View details for PubMedID 23997039

  • A combined additive manufacturing and micro-syringe deposition technique for realization of bio-ceramic structures with micro-scale channels INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY Vlasea, M., Shanjani, Y., Bothe, A., Kandel, R., Toyserkani, E. 2013; 68 (9-12): 2261-2269
  • Solid freeform fabrication of porous calcium polyphosphate structures for bone substitute applications: in vivo studies. Journal of biomedical materials research. Part B, Applied biomaterials Shanjani, Y., Hu, Y., Toyserkani, E., Grynpas, M., Kandel, R. A., Pilliar, R. M. 2013; 101 (6): 972-980

    Abstract

    Porous calcium polyphosphate (CPP) structures with 30 volume percent porosity and made by solid freeform fabrication (SFF) were implanted in rabbit femoral condyle sites for 6-wk periods. Two forms of SFF implants with different stacked layer orientation were made in view of prior studies reporting on anisotropic/orthotropic mechanical properties of structures so formed. In addition, porous CPP implants of equal volume percent porosity made by conventional sintering and machining methods were prepared. Bone ingrowth and in vivo degradation of the three different implant types were compared using back-scattered scanning electron microscopy (BS-SEM) of implant samples and quantitative analysis of the images. The results indicated bone ingrowth with all samples resulting in 30-40% fill of available porosity by bone within the 6-wk period. In the 6-wk in vivo period, approximately 7-9% loss of CPP by degradation had occurred. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.

    View details for DOI 10.1002/jbm.b.32905

    View details for PubMedID 23529933

  • Characterizations of additive manufactured porous titanium implants. Journal of biomedical materials research. Part B, Applied biomaterials Basalah, A., Shanjani, Y., Esmaeili, S., Toyserkani, E. 2012; 100 (7): 1970-1979

    Abstract

    This article describes physical, chemical, and mechanical characterizations of porous titanium implants made by an additive manufacturing method to gain insight into the correlation of process parameters and final physical properties of implants used in orthopedics. For the manufacturing chain, the powder metallurgy technology was combined with the additive manufacturing to fabricate the porous structure from the pure tanium powder. A 3D printing machine was employed in this study to produce porous bar samples. A number of physical parameters such as titanium powder size, polyvinyl alcohol (PVA) amount, sintering temperature and time were investigated to control the mechanical properties and porosity of the structures. The produced samples were characterized through porosity and shrinkage measurements, mechanical compression test and scanning electron microscopy (SEM). The results showed a level of porosity in the samples in the range of 31-43%, which is within the range of the porosity of the cancelluous bone and approaches the range of the porosity of the cortical bone. The results of the mechanical test showed that the compressive strength is in the wide range of 56-509 MPa implying the effect of the process parameters on the mechanical strengths. This technique of manufacturing of Ti porous structures demonstrated a low level of shrinkage with the shrinkage percentage ranging from 1.5 to 5%.

    View details for DOI 10.1002/jbm.b.32764

    View details for PubMedID 22865677

  • Mechanical characteristics of solid-freeform-fabricated porous calcium polyphosphate structures with oriented stacked layers ACTA BIOMATERIALIA Shanjani, Y., Hu, Y., Pilliar, R. M., Toyserkani, E. 2011; 7 (4): 1788-1796

    Abstract

    This study addresses the mechanical properties of calcium polyphosphate (CPP) structures formed by stacked layers using a powder-based solid freeform fabrication (SFF) technique. The mechanical properties of the 35% porous structures were characterized by uniaxial compression testing for compressive strength determination and diametral compression testing to determine tensile strength. Fracture cleavage surfaces were analyzed using scanning electron microscopy. The effects of the fabrication process on the microarchitecture of the CPP samples were also investigated. Results suggest that the orientation of the stacked layers has a substantial influence on the mechanical behavior of the SFF-made CPP samples. The samples with layers stacked parallel to the mechanical compressive load are 48% stronger than those with the layers stacked perpendicular to the load. However, the samples with different stacking orientations are not significantly different in tensile strength. The observed anisotropic mechanical properties were analyzed based on the physical microstructural properties of the CPP structures.

    View details for DOI 10.1016/j.actbio.2010.12.017

    View details for Web of Science ID 000288971300040

    View details for PubMedID 21185409

  • Solid freeform fabrication and characterization of porous calcium polyphosphate structures for tissue engineering purposes. Journal of biomedical materials research. Part B, Applied biomaterials Shanjani, Y., De Croos, J. N., Pilliar, R. M., Kandel, R. A., Toyserkani, E. 2010; 93 (2): 510-519

    Abstract

    Solid freeform fabrication (SFF) enables the fabrication of anatomically shaped porous components required for formation of tissue engineered implants. This article reports on the characterization of a three-dimensional-printing method, as a powder-based SFF technique, to create reproducible porous structures composed of calcium polyphosphate (CPP). CPP powder of 75-150 microm was mixed with 10 wt % polyvinyl alcohol (PVA) polymeric binder, and used in the SFF machine with appropriate settings for powder mesh size. The PVA binder was eliminated during the annealing procedure used to sinter the CPP particles. The porous SFF fabricated components were characterized using scanning electron microscopy, micro-CT scanning, X-ray diffraction, and mercury intrusion porosimetry. In addition, mechanical testing was conducted to determine the compressive strength of the CPP cylinders. The 35 vol % porous structures displayed compressive strength on average of 33.86 MPa, a value 57% higher than CPP of equivalent volume percent porosity made through conventional gravity sintering. Dimensional deviation and shrinkage analysis was conducted to identify anisotropic factors required for dimensional compensation during SFF sample formation and subsequent sintering. Cell culture studies showed that the substrate supported cartilage formation in vitro, which was integrated with the top surface of the porous CPP similar to that observed when chondrocytes were grown on CPP formed by conventional gravity sintering methods as determined histologically and biochemically.

    View details for DOI 10.1002/jbm.b.31610

    View details for PubMedID 20162726

  • Selective Laser Sintering of Calcium Polyphosphate: Finite Element Modeling and Experiments JOURNAL OF LASER MICRO NANOENGINEERING Shanjani, Y., Toyserkani, E. 2009; 4 (1): 28-34
  • Feasibility study of high frequency plasma aided rapid prototyping INTERNATIONAL JOURNAL OF MACHINE TOOLS & MANUFACTURE Mirahmadi, A., Saedodin, S., Shanjani, Y. 2007; 47 (5): 722-728
  • Numerical heat transfer modeling in coated powder as raw material of powder-based rapid prototyping subjected to plasma arc NUMERICAL HEAT TRANSFER PART A-APPLICATIONS Mirahmadi, A., Saedodin, S., Shanjani, Y. 2007; 51 (6): 593-613

Stanford Medicine Resources: