Producing Fluorine- and Lubricant-Free Flexible Pathogen- and Blood-Repellent Surfaces Using Polysiloxane-Based Hierarchical Structures

Design Principles for Immunomodulatory Biomaterials

The immune system is imperative to the survival of all biological organisms. A functional immune system protects the organism by detecting and eliminating foreign and host aberrant molecules. Conversely, a dysfunctional immune system characterized by an overactive or weakened immune system causes life-threatening autoimmune or immunodeficiency diseases. Therefore, a critical need exists to develop technologies that regulate the immune system to ensure homeostasis or treat several diseases. Accumulating evidence shows that biomaterials─artificial materials (polymers, metals, ceramics, or engineered cells and tissues) that interact with biological systems─can trigger immune responses, offering a materials science-based strategy to modulate the immune system. This Review discusses the expanding frontiers of biomaterial-based immunomodulation, focusing on principles for designing these materials. This Review also presents examples of immunomodulatory biomaterials, which include polymers and metal- and carbon-based nanomaterials, capable of regulating the innate and adaptive immune systems.

Micro-/Nanohierarchical Structures Physically Engineered on Surfaces: Analysis and Perspective

The high demand for micro-/nanohierarchical structures as components of functional substrates, bioinspired devices, energy-related electronics, and chemical/physical transducers has inspired their in-depth studies and active development of the related fabrication techniques. In particular, significant progress has been achieved in hierarchical structures physically engineered on surfaces, which offer the advantages of wide-range material compatibility, design diversity, and mechanical stability, and numerous unique structures with important niche applications have been developed. This review categorizes the basic components of hierarchical structures physically engineered on surfaces according to function/shape and comprehensively summarizes the related advances, focusing on the fabrication strategies, ways of combining basic components, potential applications, and future research directions. Moreover, the physicochemical properties of hierarchical structures physically engineered on surfaces are compared based on the function of their basic components, which may help to avoid the bottlenecks of conventional single-scale functional substrates. Thus, the present work is expected to provide a useful reference for scientists working on multicomponent functional substrates and inspire further research in this field.

Highly Stable Hierarchically Structured All-Polymeric Lubricant-Infused Films Prevent Thrombosis and Repel Multidrug-Resistant Pathogens

Thrombus formation and infections caused by bacterial adhesion are the most common causes of failure in blood-contacting medical devices. Reducing the interaction of pathogens using repellent surfaces has proven to be a successful strategy in preventing device failure. However, designing scale-up methodologies to create large-scale repellent surfaces remains challenging. To address this need, we have created an all-polymeric lubricant-infused system using an industrially viable swelling-coagulation solvent (S-C) method. This induces hierarchically structured micro/nano features onto the surface, enabling improved lubricant infusion. Poly(3,3,3-trifluoropropylmethylsiloxane) (PTFS) was used as the lubricant of choice, a previously unexplored omniphobic nonvolatile silicone oil. This resulted in all-polymeric liquid-infused surfaces that are transparent and flexible with long-term stability. Repellent properties have been demonstrated using human whole blood and methicillin-resistant Staphylococcus aureus (MRSA) bacteria matrices, with lubricated surfaces showing 93% reduction in blood stains and 96.7% reduction in bacterial adherence. The developed material has the potential to prevent blood and pathogenic contamination for a range biomedical devices within healthcare settings.

Superhydrophobic Biological Fluid-Repellent Surfaces: Mechanisms and Applications

Superhydrophobic biological fluid-repellent surfaces (SBFRSs) have attracted great attention in the treatment of blood and urine-related diseases because of their unique wettability and compatibility, which creates a new path for the development of medical apparatus and instruments, and are expected to create advances in various fields. Here, this review provides an up-to-date summary of research progress on the repellent mechanism and application of SBFRSs. The underlying physical and chemical principles for designing superhydrophobic surfaces are first introduced. Then, the dialectical influences of solid-liquid interactions between superhydrophobic surfaces and biological fluids on the wettability and compatibility are emphatically expounded. Subsequently, attention is drawn to the recent applications of SBFRSs in biomedical fields, such as surgical medical apparatus, implant materials, extracorporeal circulation devices, and biological fluid detection. Finally, the outlook and challenges in terms of employing SBFRSs are also discussed. This review is expected to provide a comprehensive guidance for the preparation of SBFRSs with compatibility and long-term superhydrophobic stability that is closely related to clinical applications.