Leaf-Inspired Micro- and Nanoengineered Surfaces for Controlled Hydrophilic and Hydrophobic Properties

A Hybrid Superhydrophobic/Hydrophilic Surface Based on SiO2 Nanoparticles over a Clay Substrate for Enhanced Dew Yield Potential

The study of SiO2 nanoparticles (NPs) and their corresponding surface modifications through octadecyltrichlorosilane (OTS) has attracted attention due to their self-cleaning, hydrophobic and superhydrophobic (SHPho) properties, which are desirable for water collection based on the dew condensation effect. Such properties have been addressed by different strategies, of which the development of hybrid superhydrophobic/hydrophilic (SHH) surfaces has shown great promise. In this research, the pairing of OTS-treated and untreated SiO2 NP layers deposited on clay substrates is investigated with the aim of exploring a hybrid SHH surface capable of enhancing dew yield behavior. Infrared analyses were conducted using FTIR to study the interaction between the clay substrate and the OTS-treated and untreated SiO2 NPs. The hybrid SHH surfaces were morphologically characterized, and contact angle (CA) measurements were performed to explore their wettability behavior. The developed hybrid SHH surfaces exhibited hydrophilic (HPhi)/SHPho properties with an improved dew yield performance. The results obtained in this article are of relevance to the development of water-harvesting devices based on hybrid SHH surfaces.

Radially patterned transplantable biodegradable scaffolds as topographically defined contact guidance platforms for accelerating bone regeneration

BACKGROUND

The healing of large critical-sized bone defects remains a clinical challenge in modern orthopedic medicine. The current gold standard for treating critical-sized bone defects is autologous bone graft; however, it has critical limitations. Bone tissue engineering has been proposed as a viable alternative, not only for replacing the current standard treatment, but also for producing complete regeneration of bone tissue without complex surgical treatments or tissue transplantation. In this study, we proposed a transplantable radially patterned scaffold for bone regeneration that was defined by capillary force lithography technology using biodegradable polycaprolactone polymer.

RESULTS

The radially patterned transplantable biodegradable scaffolds had a radial structure aligned in a central direction. The radially aligned pattern significantly promoted the recruitment of host cells and migration of osteoblasts into the defect site. Furthermore, the transplantable scaffolds promoted regeneration of critical-sized bone defects by inducing cell migration and differentiation.

CONCLUSIONS

Our findings demonstrated that topographically defined radially patterned transplantable biodegradable scaffolds may have great potential for clinical application of bone tissue regeneration.

Eggshell membrane as a bioactive agent in polymeric nanotopographic scaffolds for enhanced bone regeneration

A bone regeneration scaffold is typically designed as a platform to effectively heal a bone defect while preventing soft tissue infiltration. Despite the wide variety of scaffold materials currently available, such as collagen, critical problems in achieving bone regeneration remain, including a rapid absorption period and low tensile strength as well as high costs. Inspired by extracellular matrix protein and topographical cues, we developed a polycaprolactone-based scaffold for bone regeneration using a soluble eggshell membrane protein (SEP) coating and a nanotopography structure for enhancing the physical properties and bioactivity. The scaffold exhibited adequate flexibility and mechanical strength as a biomedical platform for bone regeneration. The highly aligned nanostructures and SEP coating were found to regulate and enhance cell morphology, adhesion, proliferation, and differentiation in vitro. In a calvaria bone defect mouse model, the scaffolds coated with SEP applied to the defect site promoted bone regeneration along the direction of the nanotopography in vivo. These findings demonstrate that bone-inspired nanostructures and SEP coatings have high potential to be applicable in the design and manipulation of scaffolds for bone regeneration.

Synergistic effects of gelatin and nanotopographical patterns on biomedical PCL patches for enhanced mechanical and adhesion properties

Biomedical patches have been known as important biomaterial-based medical devices for the clinical treatment of tissue and organ diseases. Inspired by the extracellular matrix-like aligned nanotopographical pattern as well as the unique physical and biocompatible properties of gelatin, we developed strength-enhanced biomedical patches by coating gelatin onto the nanopatterned surface of polycaprolactone (PCL). The relative contributions of the nanotopographical pattern (physical factor) and gelatin coating (chemical factor) in enhancing the mechanical and adhesive properties of PCL were quantitatively investigated. The nanotopographical pattern increased the surface area of PCL, allowing more gelatin to be coated on its surface. The biomedical patch made from gelatin-coated nanopatterned PCL showed strong mechanical and adhesive properties (tensile strength: ~14.5 MPa; Young's modulus: ~60.2 MPa; and normal and shear adhesive forces: ~1.81 N/cm² and ~352.3 kPa) as well as good biocompatibility. Although the nanotopographical pattern or gelatin coating alone could enhance these physical properties of PCL in both dry and wet environmental conditions, both factors in combination further strengthened the properties, indicating the importance of synergistic cues in driving the mechanical behavior of biomedical materials. This strength-enhanced biomedical patch will be especially useful for the treatment of tissues such as cartilage, tendon, and bone.