Metastable Calcium Phosphate Cluster-Involved Mineralization Process Regulated by a Dual Biomolecule System Toward the Application in Dentinal Tubules Occlusion

Abstract

Dentin hypersensitivity caused by the exposure of dentinal tubules is affecting a significant portion of the population. With promising prospects, the biomimetic mineralization materials used in treating dentin hypersensitivity are expected to possess a metastable characteristic, for which they can easily penetrate the tubules and the surrounding tissues, but then occlude them via a transformation of size and phase immediately. Herein, this study develops a metastable calcium phosphate cluster (MCPC)-involved mineralization process, which is regulated by dual biological macromolecules: bovine serum albumin (BSA) and poly-L-lysine (PLL). BSA functions to stabilize the primary calcium phosphate clusters; PLL further tunes the cluster's evolution (toward larger and crystalline particles) into a metastable fashion, and meanwhile inhibits the local bacteria. Upon treatments, the system generates amorphous MCPC with ultrasmall size (1–2 nm); then they enter the deep dentinal tubules, subsequently aggregate and crystalline into immobile larger particles, which finally seal the exposed dentinal tubules. The effective occlusion of dentinal tubules as well as significant antibacterial performance are confirmed both in vivo and in vitro. This study has devised not only a regulatory approach for the evolution of mineralization-active clusters but also established an efficient method for managing dentin hypersensitivity.