Role of Driving Force on Engineering Layer-by-Layer Protein/Polyphenol Coating with Flexible Structures and Properties

Abstract

Protein-based coatings are of immense interest due to their rich biological functions. Layer-by-layer (LbL) assembly, as a powerful means of transferring protein functions to the material surface, has received widespread attention. However, the assembly mechanism of protein-based LbL coatings is still far from being explained, not only because of protein structure and function diversity but also characterization limitations. Herein, we monitored in situ the LbL assembly process of tannic acid (TA) and lysozyme (Lyz), a classic pair of polyphenol and protein, by combining quartz crystal microbalance with dissipation monitoring (QCM-D) and spectroscopic ellipsometry (SE). The water content, morphology, mechanical properties, antioxidant activity, and the driving force of TA-Lyz coating engineered under different pH values were analyzed in detail by various techniques. The water content, a key factor in TA-Lyz coatings, increased with increasing assembled pH values, which resulted in a porous morphology, inhomogeneous mechanical distribution, faster assembly growth, and better antioxidant activity in both acellular and cellular levels. In addition, high water content is unfavorable to both entropy and enthalpy changes, and the thermodynamic driving force of TA and Lyz assembly mainly comes from the enthalpy change brought by the noncovalent interaction between TA and Lyz. These results provide new insights into engineering the structure, function, and assembly mechanisms of protein-based coatings.

Presenting dual-functional peptides on implant surface to direct in vitro osteogenesis and in vivo osteointegration

“…This was mainly attributed to the electrostatic interactions between TA and assembled unit R6. The pKa1 and pKa2 of TA are about 3.3 and 8.7, respectively [ 39 ]. At pH 5.5, partial phenol groups in TA were deprotonated, and more TA was negatively charged with increased pH, which contributed to the increased thickness from pH 5.5 to pH 7.…”

Recent Progress in Protein-Polyphenol Assemblies for Biomedical Applications

“…The results demonstrated that this simple strategy was applicable to diverse substrates across multiple length scales from 20 nm to 1 cm. Zan’s group − constructed a series of protein-polyphenol coatings, such as gelatin/TA, Lys/TA, and Lys/TA/GO multilayer thin films, via dip coating onto a variety of substrates including glass, silicon, titanium, and gold-coated quartz crystals (sensors for the quartz crystal microbalance (QCM)). Related to the physiochemical properties of TA and proteins used, these multilayer thin films exhibited one or more properties of antioxidant, antibacterial, fast cell attachment, and enhanced osteogenesis, which pave the way for fabricating coatings for bone-related implants.…”

“…Related to the physiochemical properties of TA and proteins used, these multilayer thin films exhibited one or more properties of antioxidant, antibacterial, fast cell attachment, and enhanced osteogenesis, which pave the way for fabricating coatings for bone-related implants. It was found that the pH value affected the water content of the assembled multilayer films and TA-induced conformational transition of proteins and then affected the growth and mechanical properties of the assembled films. , Similarly, Iqbal et al built collagen-TA LbL multilayer films in acetate or citrate buffers of the same pH value and found that the type of buffer affected the morphology and antibacterial properties of the multilayer films. Currently, Yang et al combined a natural flavonoid drug, baicalein (BAI), which could promote osteoblast mineralization, with BSA via a desolvent method before LbL assembling with TA, and the multilayer films had great antioxidant and osteogenesis properties.…”

Protein-based bioactive coatings: from nanoarchitectonics to applications

“…221 Furthermore, interactions between proteins and polyphenols, 222 like tannic acid, have been explored for various applications, including catalysis, fluorescence imaging, and cell targeting. Multilayered bioactive coatings comprising tannic acid and lysozyme have been tailored to enhance antioxidative, antibacterial, 223 and osteogenesis-promoting attributes, 224 with further investigations into cell adhesion and proliferation. 225…”