en Research Paper Research Paper <div style="text-align: justify;"><span style="font-size:11pt"><span style="line-height:115%"><span sans-serif="" style="font-family:Calibri,"><b><span style="font-size:12.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times="">Abstract. </span></span></span></b><span style="font-size:12.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times="">Hydroxyapatite (HA) scaffold is commonly used in the applications of bone tissue engineering due to its bioactivity and equivalent chemical composition to the inorganic constituents of human bone. The present study focused on the fabrication of porous 3D hydroxyapatite scaffold which was modified by polymer coating as a successful strategy to improve the mechanical properties. A <span style="background:white">3D porous hydroxyapatite scaffolds were fabricated by gel-casting method by using freshly extracted egg yolk (EY) with (50 and 60)wt% of HA powder. To enhance the mechanical properties, composite <st1:stockticker w:st="on">PVA</st1:stockticker>/ HA scaffolds were produced by using dip coating in Polyvinyl alcohol (<st1:stockticker w:st="on">PVA</st1:stockticker>). </span>Fourier transform infrared spectroscopy (FTIR) was used to recognize the functional group associated with the hydroxyapatite scaffolds before and after <st1:stockticker w:st="on">PVA</st1:stockticker> coating.<span style="background:white"> The physical (density and porosity) and mechanical (compressive strength and elastic modulus) properties were investigated before and after coating. <st1:stockticker w:st="on">SEM</st1:stockticker> was used to inspect the surface morphology and pore modification of the scaffolds. Wettability was determined by using a water contact angle to analyze the scaffold hydrophobicity. Surface roughness</span></span></span></span> <span style="font-size:12.0pt"><span style="background:white"><span style="line-height:115%"><span new="" roman="" style="font-family:" times="">was studied by atomic force microscopy (AFM). It was </span></span></span></span><span style="font-size:12.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times="">revealed that<span style="background:white"> the scaffold porosity decreased with increase solid loading of HA powder in the gel and after <st1:stockticker w:st="on">PVA</st1:stockticker> coating. The findings showed that <st1:stockticker w:st="on">PVA</st1:stockticker> coating improved mechanical strength of scaffold to be double by covering the small pores and filling microcracks sited on the scaffold strut surfaces, inducing a crack bridging mechanism.</span></span></span></span> <span style="font-size:12.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times="">The</span></span></span> <span style="font-size:12.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times="">scaffolds&rsquo; strength</span></span></span> <span style="font-size:12.0pt"><span style="background:white"><span style="line-height:115%"><span new="" roman="" style="font-family:" times="">was in the range of trabecular bone strength. This indicates </span></span></span></span><span style="font-size:12.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times="">&nbsp;non-load bearing applications.</span></span></span></span></span></span></div> biologic hydroxyapatite,gel-casting,egg yolk,Polyvinyl alcohol,3D porous scaffold. 1 10 http://ijmse.iust.ac.ir/browse.php?a_code=A-10-4017-2&slc_lang=en&sid=1 Israa Khahtan Sabree mat.asraa.kahtan@uobabylon.edu.iq 1800319475328460017303 1800319475328460017303 Yes Th University of Babylon Batool Abd Aladel Jabar batool.abduladel@yahoo.com 1800319475328460017304 1800319475328460017304 No The University of Babylon