Abstract: Bisphosphonate Delivery to Bones Using Cell Membrane-Coated Nanoparticles
The National Osteoporosis Foundation (NOF) estimated that there are 54 million people in the United States that have low bone mass, which increases the risk of developing osteoporosis. In addition to this, the NOF also estimates that 10 million Americans have osteoporosis and 80% of individuals with osteoporosis are women. Bone density is vital to allowing uninterrupted movement and structural support in the body. Osteoporosis threatens mobility and increases the risk of bone fracture by decreasing bone density through the overactivity of osteoclasts. The projected medical costs associated with osteoporosis-related expenditures are projected to reach $25.3 billion per year by the year 2025. While treatments have been developed to suppress the activity of osteoclasts, their lack of specificity allows for interactions with the hydroxyapatite matrix of bone, which makes uptake by osteoclasts irregular. This lack of predictability is detrimental to the creation of a balance between osteoblast and osteoclast activity which is necessary to combat osteoporosis. Amino bisphosphonates (nBPs) are commonly employed to treat individuals suffering from osteoporotic diseases. These medications have also been heavily investigated for their compatibility with nanoparticle systems.
In recent years, the field of therapeutics has made efforts to develop new approaches for the treatment of diseases, such as osteoporosis, by utilizing nanoparticle drug delivery systems. These systems are appealing because of their ability to ensure precise and targeted delivery of medicines. Although they can effectively deliver therapeutics, many of these nanoplatforms encounter issues of biocompatibility and immunocompatibility. These are observed by a nanoparticle’s immune activation and premature clearance from the body. Although biodegradable nanoplatforms have been developed with immunocompatible modifications such as poly(ethylene glycol) conjugation (PEGylation), as a foreign body, they are still prone to low circulation times and the promotion of anti-PEG antibodies. One alternative is the use of cell membrane encapsulates that introduce “markers of self” that are recognized by the immune system and are given the allowance to circulate the body. Our approach at a biocompatible and immunocompatible osteoporosis treatment will take advantage of native markers present in osteoblast and platelet cells by forming a hybridized cell membrane to encapsulate poly(lactic-co-glycolic-acid) nanoparticles conjugated with nBPs. The anticipated results of our project will further the advancement of producing bone targeting delivery systems for osteoporosis that is an efficacious and accessible treatment option.