Due to inspiration from the Nepenthes pitcher plant, a frontier of devices has emerged with unmatched capabilities. Liquid-infused surfaces (LISs), particularly known for their liquid-repelling behavior under low tilting angles (<5°), have demonstrated a plethora of applications in medical, marine, energy, industrial, and environmental materials. This review presents recent developments of LIS technology and its prospective to define the future direction of this technology in solving tomorrow’s real-life challenges. First, an introduction to the different models explaining the physical phenomena of these surfaces, their wettability, and viscous-dependent frictional forces is discussed. Then, an outline of different emerging strategies required to fabricate a stable liquid-infused interface is presented, including different substrates, lubricants, surface chemistries, and design parameters which can be tuned depending on the application. Furthermore, applications of LIS coatings in the areas of anticorrosion, antifouling, anti-icing, self-healing, droplet manipulation, and biomedical devices will be presented followed by the limitations and future direction of this technology.

Biofunctionalization of microchannels is of great concern in the fabrication of microfluidic devices. Different substrates such as glass slides, papers, polymers, and beads require different biofunctionalization approaches granting the utilization of microfluidics in several biomedical applications. Covalent immobilization of biomolecules inside the microchannels is achieved by chemical modification of the surface such as silanization or introducing different coupling agents. Although creating biointerfaces that are covalently bonded to the microchannel surface necessitates multiple steps of surface modification and incubation times, it bestows a robust biointerface capable of withstanding high shear stresses and harsh conditions without dissipating the biofunctionality. Regarding the applications that do not require robustness and long‐term stability, noncovalent attachment of biomolecules such as van der Waals and hydrophobic interactions are adequate to successfully create a functional biointerface. This review summarizes the various biofunctionalization approaches used in the most common microfluidic substrates: glass and paper. In addition, several biofunctionalization examples are proposed and described in detail along with their associated applications.

Recent studies have shown a correlation between elevated interleukin 6 (IL-6) concentrations and the risk of respiratory failure in COVID-19 patients. Therefore, detection of IL-6 at low concentrations permits early diagnosis of worstcase outcome in viral respiratory infections. Here, a versatile biointerface is presented that eliminates nonspecific adhesion and thus enables immunofluorescence detection of IL-6 in whole human plasma or whole human blood during coagulation, down to a limit of detection of 0.5 pg mL −1. The sensitivity of the developed lubricant-infused biosensor for immunofluorescence assays in detecting low molecular weight proteins such as IL-6 is facilitated by i) producing a bioink in which the capture antibody is functionalized by an epoxy-based silane for covalent linkage to the fluorosilanized surface and ii) suppressing nonspecific adhesion by patterning the developed bioink into a lubricant-infused coating. The developed biosensor addresses one of the major challenges for biosensing in complex fluids, namely nonspecific adhesion, therefore paving the way for highly sensitive biosensing in complex fluids. where significantly elevated levels indicate aggressive tumor growth or viral load and poor prognosis in patients. [2,10] Additionally, IL-6 is an important anti-inflammatory cytokine that induces acute responses in chronic inflammatory pathologies. As such, there has been an increasing interest in the use of IL-6 as a biomarker for the diagnosis of early stages of viral infections, cancer, and chronic inflammation. [9-11] A practical IL-6 biosensor should provide a low limit of detection (LOD) (≤5 pg mL −1) and acceptable linear dynamic range (1-100 pg mL −1) in complex fluids, in addition to accuracy, facile operation, and amenable to mass production. [11,12] There are a large number of different IL-6 detection techniques that have been reported in the literature including electrochemical sensors, [13-22] surface plasmon resonance (SPR), [23-25] chemiluminescence immunoassay (CLIA), [26-29] and immunofluorescence assays (IFA), [30-33] Utilizing 0-and 1-D materials such as carbon nanotubes (CNTs), [14,16] nanoparticles and nanowires, [13,19] as well as porous nanoparticles, [15] optical fibers, [32] and microfluidic platforms, [28] have enabled higher sensitivity in IL-6 detection and to date, electrochemical methods have proven to be the most promising candidate for detection of IL-6 at very low concentrations (0.33 pg mL −1 in buffer) with a wide linear dynamic range. [22] While reported IL-6 biosensors have demonstrated satisfactory LODs in buffer or processed serum, their performance in human whole plasma declines significantly, leading to higher LOD's and/or false positive results. In electrochemical sensors, for example, the nonspecific attachment of biological entities in plasma or blood can interfere with the resistivity at the electrodes thereby deteriorating their sensitivity for detection of IL-6 at clinically relevant concentrations. [34] So far, the lowest theoretical LOD fo...

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structure to implement anti-wetting, self-cleaning, [5][6][7][8][9][10] anti-freezing, anti-fogging, [11] anti-microbial, [12][13][14] anti-thrombogenic, [15][16][17] corrosion resistant, [18][19][20][21][22][23] and droplet manipulating [9,[24][25][26][27][28][29] materials. Such functional materials are used as breathable wearables for protection from chemicals and oil spills, [30] aviation to prevent large amounts of adherent ice, [29] oil pipelines to resist corrosion, cultural relics restoration, [31] separation membranes and janus membranes for advanced oilwater separation, [39,40] healthcare devices and medical implants to prevent infection, [41] and self-cleaning of glass materials such as solar cells and mobile devices. [42]

Various fields within biomedical engineering have been afforded rapid scientific advancement through the incorporation of microfluidics. As literature surrounding biological systems become more comprehensive and many microfluidic platforms show potential for commercialization, the development of representative fluidic systems has become more intricate. This has brought increased scrutiny of the material properties of microfluidic substrates. Thermoplastics have been highlighted as a promising material, given their material adaptability and commercial compatibility. This review provides a comprehensive discussion surrounding recent developments pertaining to thermoplastic microfluidic device fabrication. Existing and emerging approaches related to both microchannel fabrication and device assembly are highlighted, with consideration toward how specific approaches induce physical and/or chemical properties that are optimally suited for relevant real-world applications.

Engineered surfaces that repel pathogens are of great interest due to their role in mitigating the spread of infectious diseases. A robust, universal, and scalable omniphobic spray coating with excellent repellency against water, oil, and pathogens is presented. The coating is substrate‐independent and relies on hierarchically structured polydimethylsiloxane (PDMS) microparticles, decorated with gold nanoparticles (AuNPs). Wettability studies reveal the relationship between surface texturing of micro‐ and/or nano‐hierarchical structures and the omniphobicity of the coating. Studies of pathogen transfer with bacteria and viruses reveal that an uncoated contaminated glove transfers pathogens to >50 subsequent surfaces, while a coated glove picks up 104 (over 99.99%) less pathogens upon first contact and transfers zero pathogens after the second touch. The developed coating also provides excellent stability under harsh conditions. The remarkable anti‐pathogen properties of this surface combined with its ease of implementation, substantiate its use for the prevention of surface‐mediated transmission of pathogens.

The surface fouling of biomedical devices has been an ongoing issue in healthcare. Bacterial and blood adhesion in particular, severely impede the performance of such tools, leading to poor patient outcomes. Various structural and chemical modifications have been shown to reduce fouling, but all existing strategies lack the combination of physical, chemical, and economic traits necessary for widespread use. Herein, a lubricant infused, hierarchically micro‐ and nanostructured polydimethylsiloxane surface is presented. The surface is easy to produce and exhibits the high flexibility and optical transparency necessary for incorporation into various biomedical tools. Tests involving two clinically relevant, priority pathogens show up to a 98.5% reduction in the biofilm formation of methicillin‐resistant Staphylococcus aureus and Pseudomonas aeruginosa. With blood, the surface reduces staining by 95% and suppresses thrombin generation to background levels. Furthermore, the surface shows applicability within applications such as catheters, extracorporeal circuits, and microfluidic devices, through its effectiveness in dynamic conditions. The perfusion of bacterial media shows up to 96.5% reduction in bacterial adhesion. Similarly, a 95.8% reduction in fibrin networks is observed following whole blood perfusion. This substrate stands to hold high applicability within biomedical systems as a means to prevent fouling, thus improving performance.