Single Chain Fraction Variable Binding Molecules as Bone-Targeting Therapeutics and Diagnostics

Osteoporosis is a disease characterized by lowering of bone mass and subsequent bone fracture. Although successful antiresorptive treatment options are commercially available, they have disadvantages such as poor bioavailability and significant side effects. Using phage display, an in vitro high throughput screening method, we sought to generate single chain fraction variable (scFv) against osteoclast surface receptors and bone turnover markers, for the evaluation of their potential as drug-targeted delivery platforms for improved bioavailability of current therapeutics and as immunodiagnostic assay reagents in osteoporosis. With our current in vitro result, it can be concluded that scFv, although having weaker binding affinity than IgG antibody, still possesses good selective binding against antigens. With this method of generating scFv being more cost-effective and less labour intensive, scFv reagents can become a viable option in sitedirected drug delivery and immunodiagnostic for osteoporosis and possibly for cross application to other bone-modifying disease such as osteoarthritis.