1 pH Dependent Interfacial Adhesion between Collagen and Hydroxyapatite in the Mineralized Collagen Fibril Sheikh F Ferdous 1* , ARN Sakib 1* , Ashfaq Adnan 2† 1 Graduate Student, Mechanical and Aerospace Engineering, University of Texas at Arlington, Arlington, TX 76019, USA. 2 Assistant Professor and Presenting Author, Mechanical and Aerospace Engineering, University of Texas at Arlington, Arlington, TX 76019, USA ABSTRACT The objective of this current study is to understand the molecular level mechanism of pH- dependent interface interaction process between collagen molecules (TC) and hydroxyapatite (HAP) crystals in mineralized collagen fibril. It is known that TC and HAP crystals are the two major nano-structural components of mineralized collagen fibrils. These fibrils are the sub- nanostructural members of the hierarchical organization of trabecular bone. When a trabecular bone breaks, it can be anticipated that the fracture process of the mineralized fibril level might begin from the TC-HAP interface. Studies suggest that bone fracture is a major concern for patients suffering from a disease called osteoporosis. From physiological point of view, osteoporosis occurs when bone-killing cell „osteoclasts‟ become more active than bone-forming * Both ARNS and SFF have made equal contributions in this work. † Corresponding author Phone: 817-272-2006 Email: aadnan@uta.edu