Liquid-Crystalline Hydroxyapatite/Polymer Nanorod Hybrids: Potential Bioplatform for Photodynamic Therapy and Cellular Scaffolds

Abstract

Recently, we found that self-organization of hydroxyapatite (HAp) with poly(acrylic acid) (PAA) leads to the formation of liquid-crystalline (LC) nanorod hybrids that form aligned films and show stimuli-responsive properties. Here, we demonstrate that these biocompatible HAp/PAA hybrid nanorods represent a platform technology as drug nanocarriers for photodynamic cancer therapy and as bioscaffolds for the control of cellular alignment and growth. To use hybrid nanorods as a drug nanocarrier, we introduced methylene blue (MB), a typical photosensitizer for photodynamic therapy, into the PAA nanolayer covering the surface of the HAp nanocrystals through electrostatic interactions. The stable MB-loaded HAp/PAA hybrid nanorods efficiently produced singlet oxygen from MB upon light irradiation and showed remarkable photodynamic therapeutic effects in cancer cells. Moreover, taking advantage of the mechanically responsive LC alignment properties of the HAp/PAA hybrid nanorods, macroscopically oriented bioscaffolds were prepared through a spin-coating process. The cells cultured on the oriented scaffolds showed cellular alignment and elongation along the oriented direction of the hybrid nanorods. The HAp/PAA hybrid nanorods demonstrate potential in drug delivery and tissue engineering. These unique LC HAp/PAA hybrid nanorods have significant potential as a platform for the development of various types of biomaterial.

Modern World Applications for Nano-Bio Materials: Tissue Engineering and COVID-19

“…Simultaneously, they have also been studied for drug delivery due to their ease of functionalization (Perez-Juste et al, 2005;Smith et al, 2009). Calcium phosphate nanorods, mainly hydroxyapatite, have been used both as nanocarriers and for bone tissue regeneration in composite scaffolds (Rubin et al, 2003;Nga et al, 2014;Dave et al, 2019;Li et al, 2019;Nakayama et al, 2019).…”

Supramolecular Association and Nanostructure Formation of Liquid Crystals and Polymers for New Functional Materials

“…107LC nanorod materials of HAp were also developed. (121)(122)(123)(124) Due to biocompatibility and osteoconductivity, HAp has attracted much attention as biomaterials including artificial bones, and dental implants Control of morphologies and orientation is important for HAp-based materials. Amorphous calcium phosphate stabilized by PAA was used for precursors to develop HAp colloidal liquid crystals.…”

“…Oriented HAp thin solid films with unidirectional alignment and radial alignment were obtained by mechanical shearing and spincoating of the LC colloids of HAp nanorods, respectively. (121,123) It was shown that HAp nanorod hybrids was used as drug nanocarriers for photodynamic cancer therapy and can also act as bioscaffolds for cellular alignment and growth. (123)…”

“…(121,123) It was shown that HAp nanorod hybrids was used as drug nanocarriers for photodynamic cancer therapy and can also act as bioscaffolds for cellular alignment and growth. (123)…”

Bioinspired selective synthesis of liquid-crystalline nanocomposites: formation of calcium carbonate-based composite nanodisks and nanorods

“…14 For example, hydroxyapatite/polymer hybrid nanorods exhibit colloidal liquid-crystalline (LC) states that are responsive to magnetic elds and biocompatible properties. [15][16][17] Development of sustainable materials is important to address global environmental issues. Biominerals are structurally controlled biological hard tissues such as nacre from seashells and egg shells, which are good models for sustainable materials.…”