Search Results (6,652)

Agarose, a naturally derived marine polysaccharide extracted from red algae, has evolved from a conventional electrophoretic matrix into a multifunctional biomaterial platform for biomedical engineering. Its thermoreversible gelation, tunable pore structure, optical transparency, generally low immunogenicity under tested conditions, and chemical modifiability enable applications in tissue engineering, drug delivery, molecular diagnostics, immunomodulation, and cell preservation. This review critically examines recent advances in agarose-based biomaterials, with emphasis on structure–property relationships, stimulus-responsive delivery systems, regenerative scaffolds, immune–material interactions, agarose-enabled diagnostic microdevices, and DMSO-free cryopreservation. Representative developments include proof-of-concept microfluidic detection of a cfDNA surrogate and histones in spiked plasma, agarose composite hydrogels for controlled release and osteochondral repair, agarose-containing composite hydrogels investigated for macrophage modulation, and agarose/trehalose systems that provide immediate post-thaw viability comparable to conventional DMSO-based preservation in the reported cell model, although post-thaw proliferation remained lower. Agarose is commercially established in electrophoresis and bioseparation, whereas therapeutic delivery and implantable regenerative systems remain predominantly preclinical. Remaining barriers include limited in vivo degradability, insufficient intrinsic cell adhesiveness and bioactivity, trade-offs among mechanical strength, injectability and printability, and incomplete manufacturing and regulatory standardization. Future work should prioritize well-defined degradation pathways, reproducible composition–property relationships, application-specific benchmarking, and clinically relevant validation. Full article

Regeneration of the osteochondral interface is essential for effective articular cartilage repair and the prevention of graft delamination. In this study, we developed a microfluidic culture device for the spatial regulation of mesenchymal stem cell (MSC) differentiation within a single-phase hydrogel by controlling concentration gradients of differentiation-inducing factors. The system comprised a PDMS culture chamber with dual-flow of culture media to generate concentration gradients of chondrogenic and osteogenic inductive factors. Numerical simulations were performed to characterize the flow velocity and distribution of factors aligned with the dual-flow direction in the hydrogel. The numerical results confirmed that the dual-flow successfully induced concentration differences between the opposite sides of the hydrogel. Bovine bone marrow-derived MSCs encapsulated in 3% agarose gel were cultured for 20 days under continuous dual-flow containing chondrogenic and osteogenic differentiation media. Histological analysis showed that the localized calcium deposition was aligned with the flow direction on the osteogenic differentiation side. In contrast, sulfated glycosaminoglycan (sGAG) synthesis was observed on the chondrogenic differentiation side. These results demonstrate that the developed culture system can successfully reconstruct an osteochondral-like interface from MSCs within a single-phase hydrogel. Full article

Bacterial persister cells are a rare subpopulation that survives antibiotic treatment without acquiring heritable resistance. Despite decades of research, concepts of bacterial persistence have evolved alongside experimental methods, yet the mechanisms underlying persistence remain debated, and different approaches often lead to seemingly conflicting conclusions. In this Review, we argue that these discrepancies arise not only from the heterogeneity of persister cells but also from differences in experimental methodology and biological context. We present persistence as a dynamic continuum extending from the physiological state preceding antibiotic exposure, through survival during treatment, recovery after antibiotic removal, and clonal expansion. We examine how experimental approaches—including CFU assays, population-based analyses, fluorescence microscopy, microfluidics, enrichment strategies, and cell sorting—interrogate different stages of this continuum, thereby addressing distinct biological questions rather than providing equivalent views of persistence. We further discuss how experimental context shapes the populations available for analysis and influences the interpretation of persistence phenotypes. Seemingly conflicting observations often arise from different experimental frameworks, each revealing a distinct aspect of bacterial persistence. Combining approaches that interrogate different stages of the continuum can strengthen persister identification and mechanistic interpretation. Recognizing these complementary perspectives is essential for accurately interpreting persistence and integrating findings across studies. Full article

On-demand droplet formation is of crucial importance to the engineering applications of droplet microfluidics. This work presents an experimental investigation on active control of droplet formation using stacked piezoelectric actuators. Two stacked piezoelectric actuators are placed adjacent to the continuous phase channel, producing periodic excitations on the continuous phase flow. It is found that droplet formation greatly depends on the excitation frequency and voltage. Droplet formation synchronizes piezoelectric excitation at a small excitation frequency, i.e., droplet formation frequency equals excitation frequency and its subharmonics. Beyond a critical value of the excitation frequency, a neglected effect of excitation frequency on droplet generation is observed. The droplet generation frequency could be increased up to ~2.6 times that without excitation. The droplet generation frequency exhibits a stepwise increase with rising excitation voltage. When the droplet formation frequency equals the excitation frequency, droplet formation undergoes filling, necking, and pinching-off. When the droplet formation frequency is half of the excitation frequency, additional refilling and re-necking stages are observed. The regime diagram of the droplet formation frequency in the synchronization mode is presented. The scaling of the generated droplet length is deduced. Since periodic excitations are employed on the continuous phase flow, the proposed active control method could minimize the detrimental impact on biochemical reagents within droplets. Full article

Human skin remains difficult to model in vitro because it brings together stratified epidermal, dermal, hypodermal, vascular, immune, appendageal, neural, and microbial elements within a single tissue. Traditional two-dimensional cultures and animal models still offer useful insight, but both have clear translational limits. Three-dimensional (3D) human skin models have therefore become increasingly valuable for mechanistic, pharmacologic, and regenerative research. This narrative review followed a fit-for-purpose literature selection framework. Priority was given to primary studies and reviews published between 2019 and 2025 that reported major advances in model architecture, biomaterials, vascularization, immune integration, appendage formation, sensorization, or translational application. Greater weight was given to studies that linked added complexity to measurable functional outputs. Current platforms include organotypic human skin equivalents, bioprinted constructs, microfluidic skin-on-a-chip systems, and pluripotent stem cell-derived organoids. Important advances include self-assembled or decellularized matrices that more closely reflect native extracellular matrix composition, perfusable microvasculature, hypodermal incorporation, immune cell integration, and real time sensing. These systems now support work in barrier testing, safety testing, dermal drug development, inflammatory dermatoses, melanoma, wound healing, aging, and regenerative transplantation. No single platform fully reproduces native human skin. The more relevant question is not how much complexity can be added, but which added features meaningfully improve performance for a defined endpoint. A fit-for-purpose framework may offer a better basis for model selection, benchmarking, standardization, and translational adoption. Future progress will depend on application specific validation, clearer performance benchmarks, scalable manufacturing, and closer alignment with regulatory and clinical needs. From that perspective, 3D skin models are best understood as complementary platforms for translational dermatology research. Full article

Red blood cell (RBC) aggregation is an important hemorheological property that influences blood viscosity, microcirculation, and stored-blood quality. However, conventional measurements commonly require repeated flow cessation or flow-rate modulation, limiting continuous monitoring and providing little information on spatial heterogeneity. This study presents a microfluidic platform for the spatiotemporal mapping of RBC aggregation during continuous blood flow. Multiple high-resistance side chambers connected to a main channel create low-shear-rate regions for aggregation while maintaining high shear in the main channel for RBC disaggregation. Flow rates and shear rates are evaluated using a hydraulic circuit model, numerical simulation, and micro-PIV measurements. An aggregation index (AI) map is introduced to quantify spatial and temporal changes in the side chambers. AI remains high and stable at flow rates of 0.5~1 mL/h. RBC aggregation increases significantly at concentrations of 15 mg/mL or with more dextran solution (C_dex). At the selected flow rate of 1 mL/h and C_dex = 40 mg/mL, the 95% confidence interval of AI is 0.477~0.600 for the proposed method, compared with 0.364~0.460 for the previous method. The proposed AI value is approximately 30% higher than that obtained using the previous method. Moreover, AI decreases progressively during four weeks of RBC storage. These findings demonstrate continuous and multiple-location detection of RBC aggregation and support the use of this platform for assessing hemorheological alterations and storage-induced RBC deterioration. Full article

Cellulose nanofibrils (CNFs) are promising renewable materials, but high fibrillation energy remains a major barrier to industrial adoption. This narrative, mechanism-focused review examines CNF production from an engineering perspective, integrating the coupled roles of feedstock structure, interfacial chemistry, hydrodynamic stress transfer, and process boundary definition. This review examines energy consumption in CNF production by linking interfacial cohesion within cellulose fiber walls, hydrodynamic stress generation in fibrillation devices, and nonproductive energy-dissipation pathways. The principal mechanical routes—high-pressure homogenization, microfluidization, grinding and refining, and high-consistency extrusion—are compared with chemical, enzymatic, and interfacial pretreatments that reduce cohesive resistance or suppress re-agglomeration. Attention is given to feedstock composition, hornification history, solids content, and process boundary definitions, because these factors strongly influence both specific energy consumption and total process energy. Across the literature, meaningful energy reduction is achieved not by equipment choice alone but by co-optimizing feedstock design, pretreatment chemistry, and stress-transfer efficiency while limiting viscous losses, elastic recovery, and fibril reassociation. The review also highlights persistent comparability problems caused by inconsistent reporting of solids content, pass number, product quality, and system boundaries. A unified framework is proposed in which energy-efficient CNF production depends on three coupled objectives: lowering interfacial cohesion, improving productive stress localization, and reducing dissipation across the full process chain while evaluating energy demand against clearly defined process boundaries and product quality endpoints. Full article

Encapsulation and coating approaches have become important tools in modern food systems for improving the stability, functionality, sensory quality, processability, and controlled delivery of bioactive and sensitive food ingredients. Their widespread adoption has enabled the incorporation of functional compounds into diverse food products while enhancing product quality, shelf life, and manufacturing performance. However, successful implementation depends not only on the encapsulation or coating strategy itself but also on the interactions among ingredient properties, carrier materials, food matrices, processing conditions, storage environments, and intended release behavior. Whereas recent reviews have mainly focused on specific encapsulation methods, carrier systems, industrial implementation, sensory functions, or regulatory aspects separately, this review integrates scientific publications and patent literature to examine method and system selection from food-engineering, formulation, processing, and industrial perspectives. Conventional processing and formulation approaches, including spray drying, freeze drying, coacervation, ionic gelation, emulsion-based encapsulation, and fluidized-bed coating, remain widely used, while established carrier systems such as liposomes and cyclodextrin inclusion complexes continue to support ingredient protection and delivery. Emerging carrier systems, including nanoemulsions, nanoliposomes, lipid nanoparticles, and hybrid multilayer structures, together with fabrication methods such as electrospraying and microfluidics, provide greater control over carrier architecture and release behavior but continue to face challenges related to manufacturing scalability, production throughput, storage stability, production cost, regulatory acceptance, and validation under industrial processing conditions. Although patent activity demonstrates continuing development of processing methods and carrier designs, patent publications alone do not establish commercial manufacture, market adoption, or industrial implementation. Across food applications, encapsulation improves ingredient protection, oxidation stability, sensory quality, dispersibility, controlled release, and process compatibility. By integrating research evidence with patent literature, this review further shows that recent progress is characterized primarily by application-driven refinement of carrier systems and fabrication methods rather than replacement of established approaches. Pet food is discussed as a representative specialized food application illustrating how encapsulation and coating strategies require adaptation to product format, processing severity, storage stability, palatability, and species-specific digestive requirements. Overall, this review highlights application-oriented food-engineering principles for selecting encapsulation methods and carrier systems suitable for industrial food applications. Full article

Food safety and quality analysis is shifting from laboratory-based end-point testing toward faster, lower-volume and matrix-adapted on-site decision-making. Near-infrared (NIR), visible-near-infrared (Vis-NIR), hyperspectral, Raman, surface-enhanced Raman scattering (SERS), fluorescence, colorimetric and terahertz approaches, together with impedance time-series readout, provide complementary information on composition, molecular vibrations, spatial distribution, reaction outputs, or electrical responses. In real foods, however, lipids, proteins, sugars, salts, pigments, particles and native fluorescence can alter spectral baselines, mass transfer and model stability. The value of microfluidics is therefore not limited to miniaturization but lies in organizing filtration, homogenization, splitting, mixing, extraction, enrichment, reaction, and readout positions into a controllable sample-to-signal workflow. This review first distinguishes chemical hazards, biological hazards, authenticity issues, and quality changes according to target and matrix characteristics, and then compares the functional boundaries of continuous-flow, paper-based, droplet, digital-hybrid and enrichment-oriented chips. It further analyses how microfluidics affects detection time, sample and reagent consumption, sensitivity, selectivity, repeatability, portability and cross-matrix applicability through spectral interfaces, signal enhancement, labelled and label-free detection, chemometrics, and machine learning. Representative applications involving pesticides, mycotoxins, pathogens, antibiotics, heavy metals, adulterants, oxidation products, and freshness indicators in real foods are discussed within a unified chain linking chip architecture, spectral signal generation and decision models. Finally, requirements for translation are proposed in terms of standard and real samples, chip-to-chip variation, external model validation, data traceability and scalable manufacturing, providing an operational framework for the joint design of broad-spectrum spectroscopic technologies and microfluidic systems. Full article

Microfluidic confinement offers new opportunities for tailoring properties of nanomaterials by applying specific dynamic and wall effects. A vibrant approach is integration of microfluidic channels with lyotropic liquid crystals and luminescent additives, which offer a variety of tunable supramolecular organizations for applications in nanotechnology and biomedicine. This paper focuses on analyzing nanoscale and microscale properties of the nanomaterials represented by tetraethylene glycol and decaethylene glycol monododecyl ethers with integrated carbon dots. Orienting impact of microchannel surfaces was found to be responsible for additional microscale ordering of the intrinsic lamellar and hexagonal structures of these composites after the phase transition from the isotropic liquid to the liquid crystalline state. Controlled and varied shear stress resulted in additional planar orientation of the composites and provided them with anisotropic luminescence properties, which were not demonstrated by macroscopic samples. Incorporation of a bioactive compound into the liquid crystalline matrix allowed obtaining the specific and detectable anisotropic luminescence response of the nanomaterials. The datasets comprising hundreds of polarized microscopy images were successfully used for training the neural network and accurate recognition of the liquid crystal type in the composites. The results will contribute to developing AI-compatible microfluidic chips, which simulate the biological capillary environment and allow for tuning properties of luminescent nanomaterials for drug delivery and biomedical applications. Full article

Accurate classification of lymphoma cell subtypes is essential for disease diagnosis and therapeutic decision-making, yet conventional approaches often rely on fluorescence labeling, labor-intensive sample preparation, and specialized instrumentation, limiting their applicability for rapid, label-free single-cell analysis. Here, we present an AI-assisted microfluidic light-scattering imaging platform for label-free classification of lymphoma cells. The platform integrates hydrodynamic focusing within a microfluidic chip, continuous acquisition of two-dimensional (2D) light-scattering patterns, automated image preprocessing, and transfer learning based on a pretrained ResNet50 network for intelligent optical feature extraction and classification. Human B lymphoma (Daudi) and T lymphoblastic lymphoma (SUP-T1) cells were used to evaluate the proposed framework. The optical imaging system was first validated using standard microspheres, demonstrating reliable acquisition of light-scattering patterns under continuous-flow conditions. A dataset comprising 800 single-cell scattering patterns was subsequently established and evaluated using stratified five-fold cross-validation. The proposed framework achieved an average classification accuracy of 94.75% with an average area under the receiver operating characteristic (ROC) curve of 0.986. By integrating microfluidic optical biosensing with deep learning, this work enables automated interpretation of intrinsic optical scattering signatures and provides a promising AI-enabled strategy for rapid, label-free lymphoma screening and intelligent healthcare applications. Full article

Versatile nanostructured materials based on electrochemically etched porous silicon (pSi) are being developed, which have tuneable pore morphology and unique optical and electrochemical properties that enable their effective biosensing applications. It has been shown that fabrication parameters critically influence pore formation and sensor performance, yet challenges remain in reproducible synthesis, structural stability and device integration. Here we review the electrochemical etching synthesis of pSi and recent advances in pSi-based optical and electrochemical biosensors for detecting bacteria, biomolecules, and viruses. We highlight strategies such as surface functionalisation, incorporation of nanomaterials, and integration with microfluidic and lab-on-a-chip technologies that enhance sensitivity and response times by addressing mass transfer limitations. These developments highlight pSi’s potential as a low-cost, adaptable biosensing material with applications in clinical diagnostics and environmental monitoring, while mapping future directions to overcome current fabrication and stability challenges. Full article

Background: The zebrafish model is extensively utilized for phenotypic screening, particularly in heart failure research. However, traditional photography-based data collection requires tricaine methanesulfonate (MS-222) anesthesia, which can suppress cardiac function and introduce artifacts. This study presents a microfluidic platform designed to facilitate anesthesia-free, noninvasive in vivo photography of zebrafish heart failure models. Methods: Isoproterenol (ISO) induced heart failure in 1 day post-fertilization (dpf) zebrafish embryos. Larvae were assigned to three groups: Control (E3 embryo medium only), Model (1 mM ISO for 48 h from 1 dpf), and Positive (1 mM ISO + 10 μM propranolol for 48 h from 1 dpf). Subsequently, a microfluidic chip featuring tapered immobilization channels was adopted. The chip facilitated the photography and collection of cardiac function parameters from lateral and supine positions, including cardiac output (CO), blood flow velocity (BFV), ejection fraction (EF), stroke volume (SV), and fractional shortening (FS). All imaging was performed in completely independent parallel experiments, with no individual larva shared between the two imaging methods. Data obtained under hydrodynamic confinement were compared with those acquired under MS-222 anesthesia. Results: Cardiac parameters measured using the microfluidic platform were significantly higher than those under MS-222 anesthesia: CO (0.339 ± 0.032 vs. 0.279 ± 0.023 nL/s, p < 0.001), BFV (681 ± 53 vs. 604 ± 38 μm/s, p < 0.001), EF (10.3 ± 0.7% vs. 6.6 ± 0.7%, p < 0.001), SV (184,519 ± 12,822 vs. 97,979 ± 5306 μm³, p < 0.001), and FS (7.3 ± 1.8% vs. 3.7 ± 0.9%, p < 0.001). Strong correlations (R² > 0.85, p < 0.0001) revealed that anesthesia underestimated parameters by 11.3–49.3%. Conclusions: Compared with the traditional anesthesia-based method, the microfluidic platform enables more precise cardiac parameter collection in a zebrafish heart failure model than when anesthesia is used, offering a reliable tool for phenotypic screening of zebrafish embryos. Full article

Bioactive polysaccharides (e.g., fucoidan, β-glucans, and medicinal plant polysaccharides) contain functional groups that interact with drug molecules, and some also retain their own biological activities. Through reversible noncovalent interactions, they can associate with small-molecule drugs and form supramolecular nanocomplexes, defined here as nanoscale assemblies in which the polysaccharide is a main structural component and its association with the drug contributes to assembly or drug retention. Multicomponent composites and bulk local matrices are discussed separately as related or extended systems. The review covers hydrogen bonding, hydrophobic association, electrostatic complexation, π–π stacking, and the cooperation among these interactions, together with the effects of pH, ionic strength, concentration, and solvent composition. Nanoprecipitation/solvent exchange, polyelectrolyte complexation, direct aqueous self-assembly, and microfluidic-assisted assembly are compared with respect to nanostructure formation, process control, and reproducibility. Molecular, colloidal, solid-state, and computational evidence is examined together when interpreting structure–assembly–performance relationships. Reported advantages include improved drug dispersibility, colloidal stability, release control, bioavailability, cellular uptake, biodistribution, and safety. In some systems, the polysaccharide itself may also contribute to therapeutic effects in tumors, inflammatory diseases, and wound healing. Related local-matrix systems are considered separately. Further development of these nanocomplexes will require better quantitative analysis of assembly mechanisms, more consistent polysaccharide characterization, careful biocompatibility assessment, scalable preparation, and longer-term safety evaluation. Full article

Conventional vibrational spectroscopy provides chemically specific identification of microplastics but often requires extensive sample preparation and particle-by-particle analysis. This study numerically examines a terahertz split-ring resonator (SRR) metasurface as a transducer for local dielectric perturbations in water. A finite-element model was used to quantify the spatial response of the active gap. A 5 × 5 sensitivity map yielded frequency shifts of 0.37–0.97 GHz for equivalent local polystyrene perturbations, with maxima at the gap corners, consistent with simulated field localization. An equal-volume shape study compared a spherical inclusion (Δf = 4.34 GHz) with ellipsoids of identical volume and constant height; shifts of 4.25–4.56 GHz demonstrated dependence on in-plane orientation. At the highest-sensitivity cell, shifts of 1.12, 0.97, 0.69, 0.25, and 0.24 GHz were obtained for PE, PS, PET, and two synthetic high-permittivity references, respectively. For three four-corner configurations, the observed shifts agreed with reference-cell estimates within 1.4%. The results identify positional, dielectric, and geometric factors that should be controlled in future microfluidic preconcentration and hybrid-sensing experiments. Full article