# Lithographically-Fabricated HA-Incorporated PCL Nanopatterned Patch for Tissue Engineering
###### Abstract  
Inspired by the aligned extracellular matrix and bioceramics in human bone tissue, we investigated the relative contributions of nanotopography and equine bone powders (EBPs) with human dental pulp stem cells (DPSCs) to the osteogenesis. Both nanotopography and EBPs independently promoted the osteogenesis of DPSCs, osteogenesis was further promoted by the two factors in combination, indicating the importance of synergistic design factor of guided bone regeneration (GBR) membrane. The osteogenesis of DPSCs was affected by the polycaprolactone-based nanotopography of parallel nanogrooves as well as EBPs coating. Interestingly, both nanopattern and EBPs affected the DPSCs morphologies; nanopattern led to cell elongation and EBPs led to cell spreading and clustering. Analysis of the DPSCs-substrate interaction, DPSCs-EBPs interaction suggests that the combined environment of both factors play a crucial role in mediating osteogenic phenotype. This simple method to achieve a suitable environment for osteogenesis via nanotopography and EBPs coating modulation may be regarded as a promising technique for GBR/GTR membranes, which widely used dental and maxillofacial surgery applications. nanogrooves; PCL patches; equine bone powder; dental pulp stem cells +
Footnote †: journal: AppliedThe composition of in vivo-like synthetic nanostructured matrices to promote stem cell function and behavior, such as attachment, proliferation and differentiation, has been regarded as a topic of interest in the field of tissue regeneration; it is important to control the surface topography at a nanoscale resolution [9; 10]. Currently, various technologies for micro-, nanofabrication such as electron beam- or photolithography [11], self-assembling systems [12], micro-contact printing [13], particle synthesis [14], replica casting or modeling [15], chemical etching [16], sandblasting [17], and electrospinning [18] have advantages and limitations respectively. For example, electrospun fiber mesh has the advantage of being easy to obtain non-woven, anisotropic aligned mesh consisting of large amounts with nanoscale fibers using various biocompatible polymers. However, they have some drawbacks as a substrate for cell cultures such as difficulties to penetrate cells between mesh and to have a consistent thickness of fibers in mesh, as well as having precisely defined nanopatterns. Compared to the electrospinning, it has been known that the soft lithographic techniques are more precise, achieving 2D matrices, and can circumvent low yield of electrospinning technique. The typical forms of nanotopographical pattern--nanogroove, nanopits, and nanowire--could be generated by using soft lithography techniques. Especially, it was found that nanogrooves patterned substrate could enhance initial cell extension, direct cell elongation (orientation), controlling cell migration along nanogrooves, and promote cell differentiation. [PERSON] et al observed that in the presence of differentiation media, nanogrooves (650 nm) enhanced mesenchymal stem cells (MSCs) differentiation into both osteogenic and adipogenic lineages. In addition, [PERSON] et al observed the NIH/3T3 cell migration on the anisotropic nanotopographic pattern arrays with variable local sizes (300-800 nm), and the cell migration was most rapidly on the dense nanopattern (300 nm) [19]. These findings have supported the importance of nanotopographical features for stem cell fate and biomedical applications. Calcium phosphate (CaP) is a major inorganic component of animal bones and teeth. Hydroxyapatite (HAp), biphasic calcium phosphate (BCP), and \(\beta\)-tricalcium phosphate (\(\beta\)-TCP) have been known as the most representative materials of CaP, which is known as a material that is well integrated with adjacent bone tissue that can promote bone regeneration [20; 21].