Adsorption and desorption behaviors of cetylpyridinium chloride on hydroxyapatite nanoparticles with different morphologies

Water-Mediated On-Demand Detachable Solid-State Adhesive of Porous Hydroxyapatite for Internal Organ Retractions

Novel adhesives for biological tissues offer an advanced surgical approach. Here, the authors report the development and application of solid-state adhesives consisting of porous hydroxyapatite (HAp) biocompatible ceramics as novel internal organ retractors. The operational principles of the porous solid-state adhesives are experimentally established in terms of water migration from biological soft tissues into the pores of the adhesives, and their performance is evaluated on several soft tissues with different hydration states. As an example of practical medical utility, HAp adhesive devices demonstrate the holding ability of porcine livers and on-demand detachability in vivo, showing great potential as internal organ retractors in laparoscopic surgery.

Adsorption of Cetylpyridinium Chloride at Silica Nanoparticle/Water Interfaces (I): Dependence of Adsorption Equilibrium on Particle Size

In the current work, a size-effect model was developed to describe the particle size-dependence of adsorption at solid/liquid interfaces. A parameter, ΔQ_ad, was introduced, defined as the change of the product of the solid/liquid interfacial tension and the molar volume of solid surface components caused by adsorption. The model predicts that with a decrease in particle radius (r), the saturation adsorption amount per unit area (Γ_m, mol/m²) decreases, while the change of the adsorption equilibrium constant (K_ad) is determined by the ΔQ_ad, namely, it decreases if ΔQ_ad > 0 but increases if ΔQ_ad < 0. There exists a critical r at which the saturation adsorption amount per unit mass (Γ_m^g, mol/g) attains a maximum. In addition, the adsorption of cetylpyridinium chloride (CPyCl), a cationic surfactant, on silica nanoparticles with different r (ca. 6-61 nm) values was determined at 298 K and pH 9, showing an obvious size-dependence. With a decrease in r, K_ad and Γ_m decrease, indicating a decrease in the affinity of silica particles toward CPyCl. The size-dependent adsorption data can be well described using our model. Adsorption can affect the molar volume of the solid surface phase, which plays an important role in the size-dependence of adsorption. This work provides a better understanding of the size-dependent adsorption phenomenon at solid/liquid interfaces.

Biocompatible nanostructured solid adhesives for biological soft tissues

Over the past few years, the development of novel adhesives for biological soft tissue adhesion has gained significant interest. Such adhesives should be non-toxic and biocompatible. In this study, we synthesized a novel solid adhesive using nanostructured hydroxyapatite (HAp) and evaluated its physical adhesion properties through in vitro testing with synthetic hydrogels and mouse soft tissues. The results revealed that HAp-nanoparticle dispersions and HAp-nanoparticle-assembled nanoporous plates showed efficient adhesion to hydrogels. Interestingly, the HAp plates showed different adhesive properties depending upon the shape of their nanoparticles. The HAp plate made up of 17nm-sized nanoparticles showed an adhesive strength 2.2times higher than that of the conventional fibrin glue for mouse skin tissues.

STATEMENT OF SIGNIFICANCE

The present study indicates a new application of inorganic biomaterials (bioceramics) as a soft tissue adhesive. Organic adhesives such as fibrin glues or cyanoacrylate derivatives have been commonly used clinically. However, their limited biocompatibility and/or low adhesion strength are some drawbacks that impair their clinical application. In this study, we synthesized a novel solid adhesive with biocompatible and biodegradable HAp nanoparticles without the aid of organic molecules, and showed a rapid and strong adhesion of mouse soft tissues compared to conventional fibrin glues. Given the importance of wet adhesion in biomedicine and biotechnology applications, our results will help not only in developing an efficient approach to close incised soft tissues, but also in finding novel ways to integrate soft tissues with synthetic hydrogels (such as drug reservoirs).