Biomimetic calcium phosphate coating as a drug delivery vehicle for bone tissue engineering: A mini-review

The high incidence of bone defect cases necessitates a rapid development of cost-effective bone tissue engineering approaches. Bone growth factors such as bone morphogenetic protein-2 (BMP-2) play a vital role in bone tissue engineering. The osteoinductive efficacy of BMP-2 and other osteogenic growth factors is highly dependent on their dose and delivery mode. Slow and sustained delivery of a low dose of BMP-2 promotes bone defect healing. However, the burst release of a high dose of BMP-2 not only fails to promote bone healing but also causes adverse local and systemic effects. The biomimetic calcium phosphate (BioCaP) coating technique guarantees a slow, gradual, and local release of BMP-2 to mimic its natural release from the bone matrix under physiological conditions. Therefore, BioCaP coatings have long been regarded as a promising drug carrier for growth factors. In this mini-review, we give a brief introduction to BioCaP coatings regarding their preparation techniques, physicochemical properties, potential as a drug carrier, ability to suppress foreign body reactivity, and their preclinical application in ectopic and orthotopic models. Finally, the current challenges and future prospects of BioCaP coatings are discussed.