Bisphosphonate-coated BSA nanoparticles lack bone targeting after systemic administration.

Area of Science:

• Biomaterials Science
• Nanotechnology
• Drug Delivery

Background:

• Bone morphogenetic protein-2 (BMP-2) is crucial for bone regeneration but requires effective delivery systems.
• Polymeric nanoparticles offer potential for targeted delivery, but achieving bone specificity remains a challenge.

Purpose of the Study:

• To develop and characterize bone morphogenetic protein-2 (BMP-2) loaded nanoparticles for bone-specific delivery.
• To evaluate the efficacy of polyethyleneimine-graft-poly(ethylene glycol) and bisphosphonic acid (PEI-PEG-thiolBP) conjugate-coated nanoparticles for bone repair and regeneration.

Main Methods:

• Preparation of PEI-PEG-thiolBP conjugate-coated bovine serum albumin (BSA) nanoparticles (NPs).
• Characterization of NPs for size, zeta-potential, morphology, and in vitro cytotoxicity.
• Assessment of BMP-2 bioactivity, hydroxyapatite (HA) affinity, and in vivo retention and biodistribution.

Main Results:

• NP characteristics were tunable by conjugate substitution ratios and coating parameters.
• PEG modification reduced NP toxicity; BMP-2 retained bioactivity in coated NPs (except PEI-coated).
• NPs demonstrated HA affinity and improved in vivo BMP-2 retention, but lacked bone targeting after intravenous administration.

Conclusions:

• PEI-PEG-thiolBP coated NPs are suitable for localized BMP-2 delivery in bone repair.
• The bisphosphonic acid conjugation did not confer bone targeting ability upon intravenous injection.