Biosensors, which combine physical transducers with biorecognition elements, have seen significant advancement due to the heightened interest in rapid diagnostic technologies across a number of fields, including medical diagnostics, environmental monitoring, and food safety. In particular, polydiacetylene (PDA) is gaining attention as an ideal material for label-free colorimetric biosensor development due to its unique color-changing properties in response to external stimuli. PDA forms through the self-assembly of diacetylene monomers, with color change occurring as its conjugated backbone twists in response to stimuli such as temperature, pH, and chemical interactions. This color change enables the detection of biomarkers, metal ions, and toxic compounds. Moreover, the combination of PDA with polymeric structures including hydrogels further enhances the sensitivity and structural stability of PDA-based biosensors, making them reliable and effective in complex biological and environmental conditions. This review comprehensively examines recent research trends and applications of PDA–polymeric structure hybrid biosensors, while discussing future directions and potential advancements in this field.

Caenorhabditis elegans (C. elegans) possesses several features ideal for biological research, including a transparent body, a short life cycle, and high genetic homology with humans. These characteristics have established it as a premier model organism in the life sciences. However, traditional methods for C. elegans phenotyping, which typically involve cultivation on agar plates and manual quantification, face significant limitations in throughput, objectivity, and precise environmental control. Microfluidic technology has emerged to overcome these challenges, offering precise environmental control and enabling high-throughput studies. This review focuses on the synergistic interplay between microfluidic platforms, advanced imaging systems, and automated image-based quantitative analysis for comprehensive C. elegans phenotyping. We examined microfluidic techniques for spatially confining and immobilizing C. elegans, innovations in imaging hardware and computational image enhancement tailored for these systems, and the pivotal role of artificial intelligence in robustly quantifying complex phenotypes of C. elegans. The integration of these technologies allows for high-precision, high-throughput analysis of morphology, behavior, and subcellular events in C. elegans. This synergy significantly advances diverse fields such as neurobiology, developmental biology, drug screening, and aging research with C. elegans. Future perspectives include the development of standardized, intelligent, and automated platforms to further unlock the potential of the C. elegans model.

Microfluidics and biochip technologies continue to play a key role in driving innovation across biomedical, environmental and engineering disciplines [...]

Recent studies have demonstrated the clinical potential of nucleic acid therapeutics (NATs). However, their efficient and scalable delivery remains a major challenge for both ex vivo and in vivo gene therapy. Microfluidic platforms have emerged as a powerful tool for overcoming these limitations by enabling precise intracellular delivery and consistent therapeutic carrier fabrication. This review examines microfluidic strategies for gene delivery at the cellular level. These strategies include mechanoporation, electroporation, and sonoporation. We also discuss the synthesis of lipid nanoparticles, polymeric particles, and extracellular vesicles for systemic administration. Unlike conventional approaches, which treat ex vivo and in vivo delivery as separate processes, this review focuses on integrated microfluidic systems that unify these functions. For example, genetic materials can be delivered to cells that secrete therapeutic extracellular vesicles (EVs), or engineered cells can be encapsulated within hydrogels for implantation. These strategies exemplify the convergence of gene delivery and carrier engineering. They create a single workflow that bridges cell-level manipulation and tissue-level targeting. By synthesizing recent technological advances, this review establishes integrated microfluidic platforms as being fundamental to the development of next-generation NAT systems that are scalable, programmable, and clinically translatable.

Understanding the tear film lipid layer (TFLL) at the molecular and microphysiological levels is critical to addressing issues related to eye health and visual acuity. The composition of the TFLL, including a mixture of lipids such as wax esters and cholesterol esters, plays a key role in its ability to inhibit evaporation and maintain its interaction with the underlying aqueous layer. Recent advances in methods such as the Langmuir technique, X-ray diffraction, fluorescence imaging, and computational modeling have significantly deepened our understanding of TFLL dynamics. In particular, research has focused on how TFLL interacts with tear proteins such as lipocalin, lactoferrin, and lysozyme. These proteins are critical for maintaining the structure and spreading of the lipid layer, which in turn stabilizes the entire tear film. This review will also explore the implications of TFLL instability for conditions such as dry eye syndrome, use of contact lenses, and after ocular surgery. Ongoing research into dry eye syndrome is critical due to its prevalence and severity. Although progress has been made, many aspects of the complex functions of the TFLL remain unexplored. Future research could lead to breakthroughs in treatment and prevention, improving patients' quality of life and expanding therapeutic options.

Aquaporin (AQP) biomimetic membranes are a coming-of-age technology for water purification. Although several studies have reported aquaporin biomimetic membrane fabrication to date, these membranes show low water flux mainly due to the low porosity and inherently dense structure of the polymeric substrate materials. Herein, we report a ceramic-based aquaporin biomimetic membrane based on anodic aluminum oxide (AAO) as a substrate, which has a uniform porous structure with a high aspect ratio and pore density compared to conventional polymer substrates and exhibits a high water flux of 27.6 ± 3.6 LMH (L m−2 h−1) and superior membrane selectivity of 0.11 g L−1. Briefly, the AAO substrate was functionalized with amino-silane followed by polydopamine coating, then the AQP vesicles were immobilized on the functionalized AAO substrate surface using an electrokinetic method, and the water rejection performance of the membrane was analyzed in a forward osmosis system. Furthermore, a simple cryodesiccation method is introduced to improve the storage stability and easy transportation of aquaporin membranes, which does not require special environmental conditions to transport or store them.

Mechanically activating (MA) channels transduce numerous physiological functions. Tentonin 3/TMEM150C (TTN3) confers MA currents with slow inactivation kinetics in somato- and barosensory neurons. However, questions were raised about its role as a Piezo1 regulator and its potential as a channel pore. Here, we demonstrate that purified TTN3 proteins incorporated into the lipid bilayer displayed spontaneous and pressure-sensitive channel currents. These MA currents were conserved across vertebrates and differ from Piezo1 in activation threshold and pharmacological response. Deep neural network structure prediction programs coupled with mutagenetic analysis predicted a rectangular-shaped, tetrameric structure with six transmembrane helices and a pore at the inter-subunit center. The putative pore aligned with two helices of each subunit and had constriction sites whose mutations changed the MA currents. These findings suggest that TTN3 is a pore-forming subunit of a distinct slow inactivation MA channel, potentially possessing a tetrameric structure.

Membrane fusion, merging two lipid bilayers, is crucial for fabricating artificial membrane structures. Over the past 40 years, in contrast to precise and controllable membrane fusion in-vivo through specific molecules such as SNAREs, controlling the fusion in-vitro while fabricating artificial membrane structures in physiological ionic solutions without fusion proteins has been a challenge, becoming a significant obstacle to practical applications. We present an approach consisting of an electric field and a few kPa hydraulic pressure as an additional variable to physically control the fusion, enabling tuning of the shape and size of the 3D freestanding lipid bilayers in physiological ionic solutions. Mechanical model analysis reveals that pressure-induced parallel/normal tensions enhance fusion among membranes in the microwell. In-vitro peptide-membrane assay, mimicking vesicular transport via pressure-assisted fusion, and stability of 38 days with in-chip pressure control via pore size-regulated hydrogel highlight the potential for diverse biological applications. Membrane fusion is crucial for fabricating artificial membranes. Here, the authors present an approach combining electric field with hydraulic pressure to physically control the fusion, enabling tuning of the shape and size of the 3D freestanding lipid bilayers in physiological solutions.

Owing to their excellent durability, tunable physical properties, and biofunctionality, block copolymer-based membranes provide a platform for various biotechnological applications. However, conventional approaches for fabricating block copolymer membranes produce only planar or suspended polymersome structures, which limits their utilization. This study is the first to demonstrate that an electric-field-assisted self-assembly technique can allow controllable and scalable fabrication of 3-dimensional block copolymer artificial cell membranes (3DBCPMs) immobilized on predefined locations. Topographically and chemically structured microwell array templates facilitate uniform patterning of block copolymers and serve as reactors for the effective growth of 3DBCPMs. Modulating the concentration of the block copolymer and the amplitude/frequency of the electric field generates 3DBCPMs with diverse shapes, controlled sizes, and high stability (100% survival over 50 days). In vitro protein-membrane assays and mimicking of human intestinal organs highlight the potential of 3DBCPMs for a variety of biological applications such as artificial cells, cell-mimetic biosensors, and bioreactors.

In the current digital era, portable low-power electronics have become an essential part of our daily life, from communication to traveling, surveillance, health care, education, and industry automation. However, conventional batteries cannot meet the requirements, such as portability and sustainability, of these systems; thus, new sustainable energy sources have been identified for energy harvesting for low-power electronics. Herein, we report a simple method to enhance the energy harvesting performance by combining two different conventional materials. Polydimethylsiloxane (PDMS) and polytetrafluoroethylene (PTFE) were mixed to fabricate a high-performance liquid-solid contact-based energy harvesting film. We optimized the energy harvesting performance by optimizing crucial factors such as the film thickness, charge transfer, and contact area as a function of the mixing ratio of PDMS and PTFE. Moreover, the addition of PTFE particles to PDMS changes the surface characteristics of the film by increasing the surface roughness and charge transfer performance and enhances the mechanical stability of the film. The device shows an output voltage of 50 V under normal operation with a power density of 67.5 mu W/cm(2) across a 2 M omega resistance, which can light up 20 LEDs and charge a 1-mu F capacitor up to 22.5 V in under 40 seconds. These results show that the hybrid film can generate high-power output per area with conventional materials and can be used for energy harvesting for different electronic devices. Furthermore, this study will provide new insights to improve the performance of conventional materials for energy harvesting by optimizing their properties, such as thickness and surface morphology, by mixing different materials.

Local anesthesia is a drug that penetrates the nerve cell membrane and binds to the voltage gate sodium channel, inhibiting the membrane potential and neurotransmission. It is mainly used in clinical uses to address the pain of surgical procedures in the local area. Local anesthetics (LAs), however, can be incorporated into the membrane, reducing the thermal stability of the membrane as well as altering membrane properties such as fluidity, permeability, and lipid packing order. The effects of LAs on the membrane are not yet fully understood, despite a number of previous studies. In particular, it is necessary to analyze which is the more dominant factor, the membrane affinity or the structural perturbation of the membrane. To analyze the effects of LAs on the cell membrane and compare the results with those from model membranes, morphological analysis and 50% inhibitory concentration (IC50) measurement of CCD-1064sk (fibroblast, human skin) membranes were carried out for lidocaine (LDC) and tetracaine (TTC), the most popular LAs in clinical use. Furthermore, the membrane affinity of the LAs was quantitatively analyzed using a colorimetric polydiacetylene assay, where the color shift represents their distribution in the membrane. Further, to confirm the membrane affinity and structural effects of the membranes, we performed an electrophysiological study using a model protein (gramicidin A, gA) and measured the channel lifetime of the model protein on the free-standing lipid bilayer according to the concentration of each LA. Our results show that when LAs interact with cell membranes, membrane affinity is a more dominant factor than steric or conformational effects of the membrane.

A colorimetric polydiacetylene (PDA) paper strip sensor that can specifically recognize Bacillus thuringiensis (BT) HD-73 spores is described in this work. The target-specific aptamer was combined with PDA, and the aptamer-conjugated PDA vesicles were then coated on polyvinylidene fluoride (PVDF) paper strips by a simple solvent evaporation method. The PDA-aptamer paper strips can be used to detect the target without any pre-treatment. Using the paper strip, the presence of BT spores is directly observable by the naked eye based on the unique blue-to-red color transition of the PDA. Quantitative studies using the paper strip were also carried out by analyzing the color transitions of the PDA. The specificity of this PDA sensor was verified with a high concentration of Escherichia coli, and no discernable change was observed. The observable color change in the paper strip occurs in less than 1 h, and the limit of detection is 3 × 107 CFU/mL, much below the level harmful to humans. The PDA-based paper sensor, developed in this work, does not require a separate power or detection device, making the sensor strip highly transportable and suitable for spore analysis anytime and anywhere. Moreover, this paper sensor platform is easily fabricated, can be adapted to other targets, is highly portable, and is highly specific for the detection of BT spores.

A freestanding lipid bilayer or black lipid membrane is a powerful tool for studying ion channels and for biophysical studies of other membrane proteins under controlled chemical and physical conditions. Even though the lipid bilayer has been considered an excellent sensing platform to detect diverse single molecules from nucleotides to cells, it is not yet widely used, mainly due to its low stability and the expertise needed for membrane formation. To ameliorate the issues of conventional membrane formation techniques, we report a novel layered film that consists of a nonporous layer sandwiched between two porous layers to facilitate bilayer formation. Moreover, the absorption of excess solvent present in the membrane precursor solution can be achieved by the film, enabling control over the membrane formation process. Through this layered design, we could obtain an ideal film that has a reduced and controlled membrane formation time (<30 min) and a sufficient bilayer lifetime (3 h) for ion channel studies and biosensing.

Two chaotic micromixers (Models A and B) based on the split-and-recombine principle using multilayer microchannels are proposed and the mixing performance was analyzed numerically and experimentally for a wide range of Reynolds numbers. The fluid flow and mixing performance were numerically analyzed by solving Navier-Stokes equations. Micromixers were fabricated using a soft-lithography technique. As working fluids, water and a dye/water mixture were used. Quantitative and qualitative analyses were performed using confocal scanning microscopy and image processing techniques. The micromixers could enhance the mixing performance by expanding the interfaces between the working fluids to be mixed. The results confirm the superior mixing index of Model B compared to that of Model A.

Perturbation of potassium homeostasis can affect various cell functions and lead to the onset of programmed cell death. Although ionophores have been intensively used as an ion homeostasis disturber, the mechanisms of cell death are unclear and the bioapplicability is limited. In this study, helical polypeptide-based potassium ionophores are developed to induce endoplasmic reticulum (ER) stress-mediated apoptosis. The polypeptide-based potassium ionophores disturb ion homeostasis and then induce prolonged ER stress in the cells. The ER stress results in oxidative environments that accelerate the activation of mitochondria-dependent apoptosis. Moreover, ER stress-mediated apoptosis is triggered in a tumor-bearing mouse model that suppresses tumor proliferation. This study provides the first evidence showing that helical polypeptide-based potassium ionophores trigger ER stress-mediated apoptosis by perturbation of potassium homeostasis.

Industrialization and urbanization lead to increased generation of wastewater causing serious environmental pollution and deterioration of water quality. Membrane-based water treatment represents a major technological approach to addressing global water scarcity and environmental pollution issues. However, there has been relatively little progress in membrane technologies for water treatment mainly due to the inherent limitations of membrane materials and membrane fabrication techniques. In recent years, biomimetic membranes, such as the aquaporin membrane, have emerged as strong candidates for membrane-based water purification technology. Biomimetic approaches have the potential to overcome the problems associated with existing membranes including limited permeability, low selectivity, and excessive energy consumption. But industrial-scale defect-free biomimetic membrane fabrication remains a major challenge. Key factors that must be addressed to overcome this challenge include protein stability, membrane housing materials, and the surface chemistry and structural characteristics of the substrate. This paper reviews the state-of-the-art of membrane-based water purification technologies, summarizing the role and limitations of conventional membrane materials while evaluating the latest progress in the field of biomimetic membrane fabrication. We conclude that a thorough understanding of the relationship between substrate structure-surface properties and membrane performance is necessary for the further development and commercialization of aquaporin biomimetic membranes.

In biological cells, membrane proteins are the most crucial component for the maintenance of cell physiology and processes, including ion transportation, cell signaling, cell adhesion, and recognition of signal molecules. Therefore, researchers have proposed a number of membrane platforms to mimic the biological cell environment for transmembrane protein incorporation. The performance and selectivity of these transmembrane proteins based biomimetic platforms are far superior to those of traditional material platforms, but their lack of stability and scalability rule out their commercial presence. This review highlights the development of transmembrane protein-based biomimetic platforms for four major applications, which are biosensors, molecular interaction studies, energy harvesting, and water purification. We summarize the fundamental principles and recent progress in transmembrane protein biomimetic platforms for each application, discuss their limitations, and present future outlooks for industrial implementation.

Cl--ion transporters (2a-2h) were synthesized based on the binding motifs of prodigiosin. Transporter 2e clearly displays Cl--ion transportation activity across both model and live cell membranes. Furthermore, 2e can disrupt Ca2+ homeostasis and increase the intracellular concentration of Ca2+ in the DLD-1 cell. This disruption can lead to Caspase-dependent apoptosis supported by CHOP expression (a marker of ER stress) and the appearance of the cleaved forms of Caspase 3 and PARP.