The superhydrophobic surface has a great advantage of self-cleaning, inhibiting bacterial adhesion, and enhancing anticoagulant properties in the field of biomedical materials. In this paper, a superhydrophobic surface was successfully prepared on titanium alloy via high-speed micro-milling, anodic oxidation and fluoroalkylsilane modification. The surface morphology was investigated by scanning electron microscope and a laser scanning microscope. The surface wettability was investigated through the sessile-drop method. Firstly, regular microgrooves were constructed by micro-milling. Then, nanotube arrays were fabricated by anodic oxidation. Afterwards, fluoroalkylsilane was used to self-assemble a monolayer on the surface with a composite micro/nanostructure. Compared to polished titanium samples, the modified samples exhibited superhydrophobic properties with the water contact angle (CA) of 153.7° and the contact angle hysteresis of 2.1°. The proposed method will provide a new idea for the construction of superhydrophobic titanium surgical instruments and implants in the future.

Adhesion of bacteria and platelets on blood-contact implants and surgical devices is one of the causes of infections and thrombus. A superhydrophobic surface serving as a protective layer can minimize adhesion and contamination due to the low surface energy. The objective of this paper is to construct a superhydrophobic surface on a titanium implant by a combination of a topological structure and chemical coating. First, a micro/nano hierarchical morphology is obtained by sandblasting, acid-etching, and anodic oxidation. Then, a low surface energy coating material (fluoroalkylsilane, as the example case in this study) is used to modify the surface further. The effects of the morphology of micro and/or nanoscales and corresponding fluorination on the wettability are investigated. The results show that a hierarchical surface with microroughness and nanotubes is successfully constructed, and the contact angle (CA) is 44.9°, indicating good hydrophilicity. Interestingly, after being modified by fluoroalkylsilane, the surface converted from hydrophilic to superhydrophobic with a CA of 151.4°. In contrast, the fluorination modification of single micro or nanofeatures cannot achieve superhydrophobicity, indicating that the micro/nanostructures may show a synergistic effect for an efficient fluorination coating later on. Overall, our results demonstrate the feasibility of achieving a superhydrophobic surface via the micro/nano topological patterning and fluorination modification. The proposed method is expected to enrich the preparation technologies of superhydrophobic titanium surfaces. Graphic abstract

Vascularization is essential for realizing thick and functional tissue constructs that can be utilized for in vitro study platforms and in vivo grafts. The vasculature enables the transport of nutrients, oxygen, and wastes and is also indispensable to organ functional units such as the nephron filtration unit, the blood–air barrier, and the blood–brain barrier. This review aims to discuss the latest progress of organ-like vascularized constructs with specific functionalities and realizations even though they are not yet ready to be used as organ substitutes. First, the human vascular system is briefly introduced and related design considerations for engineering vascularized tissues are discussed. Second, up-to-date creation technologies for vascularized tissues are summarized and classified into the engineering and cellular self-assembly approaches. Third, recent applications ranging from in vitro tissue models, including generic vessel models, tumor models, and different human organ models such as heart, kidneys, liver, lungs, and brain, to prevascularized in vivo grafts for implantation and anastomosis are discussed in detail. The specific design considerations for the aforementioned applications are summarized and future perspectives regarding future clinical applications and commercialization are provided.