Biomimetic calcium phosphate/polyelectrolyte multilayer coatings for sequential delivery of multiple biological factors

Abstract

Combinations of growth factors synergistically enhance tissue regeneration, but typically require sequential, rather than co-delivery from biomaterials for maximum efficacy. Polyelectrolyte multilayer (PEM) coatings can deliver multiple factors without loss of activity; however, sequential delivery from PEM has been limited due to interlayer diffusion that results in co-delivery of the factors. This study shows that addition of a biomimetic calcium phosphate (bCaP) barrier layer to a PEM coating effectively prevents interlayer diffusion and enables sequential delivery of two different biomolecules via direct cell access. A simulated body fluid method was used to deposit a layer of bCaP followed by 30 bilayers of PEM made with poly-L-Lysine (+) and poly L-Glutamic acid (−) (bCaP-PEM). Measurements of MC3T3-E1 proliferation and viability over time on bCaP-PEM were used to demonstrate the sequential delivery kinetics of a proliferative factor (fibroblast growth factor -2 (FGF-2)) followed by a cytotoxic factor (antimycin A, AntiA). FGF-2 and AntiA both retained their bioactivity within bCaP-PEM, yet no release of FGF-2 or AntiA from bCaP-PEM was observed when cells were absent indicating a cell-mediated, local delivery process. Biomedical products that would benefit from highly localized, sequential delivery of multiple biomolecules activated by cell degradation to avoid off-target effects can benefit from this coating technique.

Cell Type Influences Local Delivery of Biomolecules from a Bioinspired Apatite Drug Delivery System

“…The bCaP deposition procedure followed a previously reported method [ 21 , 37 ]. All of the reagents were used as received from Sigma-Aldrich.…”

“…Systems of particular value are those that deliver the molecules in a highly localized manner, because that reduces the off target effects of the potent molecules being delivered [ 19 ]. The combined use of a biomimetic calcium phosphate (bCaP) barrier layer with a poly- l -Lysine (PLLys) and poly- l -Glutamic acid (PLGlut) polyelectrolyte multilayer (PEM) is one of the few systems capable of non-overlapping and the sequential delivery of two factors [ 20 , 21 ]. PEM coatings are generated by layer-by-layer assembly involving deposition of the polyelectrolyte molecules on a surface by many different techniques, including dipping into alternate solutions of differently charged molecules [ 17 , 22 , 23 ].…”

“…Despite the fact that no growth factor release was detected in the release study supernatants from the bCaP/PEM system by sensitive methods like enzyme-linked immunosorbent assay (ELISA), the coating could influence the proliferation and viability of the cells in direct contact with the coating [ 21 ]. The advantage of the highly localized, step-wise delivery of FGF-2 and BMP-2 from this bioinspired delivery system on in vivo young mouse calvarial bone repair was demonstrated [ 20 ], which validated the highly localized delivery and low dose approach.…”

Threats to adhesive/dentin interfacial integrity and next generation bio‐enabled multifunctional adhesives

“…) . Lysine has been widely used in biomaterials and studies have revealed its antibacterial properties and biofilm‐disrupting activity . When incorporated in the adhesive formulation, this essential amino acid could buffer the interfacial micro‐environment without leaching amine‐containing cytotoxic species.…”

Modulating pH through lysine integrated dental adhesives

“…Lysine, an essential amino acid, has been widely reported as an important component in biomaterials because of its biocompatibility [18–20]. Its lipophilic derivatives, lysine-based small molecules, showed commendable broad-spectrum antibacterial activity and biofilm-disrupting activity [21].…”