Recent Advances on Cell Culture Platforms for In Vitro Drug Screening and Cell Therapies: From Conventional to Microfluidic Strategies

Pipeline-free EHD Pump Based on Corona Discharge by Needle-Rod Electrode

This study introduces a pipeline-free electrohydrodynamic (EHD) pump based on corona discharge and systematically examines its performance in dielectric fluid transport, flow rate modulation, directional control, and multiphase fluid separation. Experimental results demonstrate that under a high-voltage electric field, dielectric fluids can be reliably transported along both straight and curved copper rods. Furthermore, optimizing the electrode configuration─such as incorporating additional needle electrodes─significantly extends the transport distance. Dynamic electric field control enables precise flow direction switching, offering an approach to targeted fluid transport. In oil-water mixture experiments, the EHD pump successfully achieved selective oil-phase separation while retaining the water phase, highlighting its exceptional multiphase separation capability. Overall, this study establishes the feasibility of EHD pumps for pipeline-free fluid transport and complex fluid manipulation, offering valuable insights for applications in microfluidics, biomedical engineering, and electronic liquid cooling.

Ready-to-Use Nanofiber Membrane-Integrated Organ-on-a-Chip via Cryopreservation of Cell-Loaded Microfluidic Chip

Nanofiber (NF) membrane-integrated organ-on-a-chip platforms enhance in vitro tissue barrier models by mimicking in vivo microenvironments. However, their widespread adoption has been hindered by technical complexities such as manual cell seeding. In this study, we developed ReadyChip, a cryopreserved, preseeded NF membrane-integrated organ-on-a-chip that is immediately usable upon thawing. ReadyChip showed robust post-thaw performance by preserving both the structural characteristics and compositional properties of the ECM-coated NF membrane. Its versatility was demonstrated through vascular, retinal, and blood-brain barrier models, each showing post-thaw cellular viability above 92% and sustained expression of functional markers that remained expressed after 7 days of perfusion culture. By eliminating the need for manual seeding and complex culture processes, ReadyChip offers a ready-to-use platform that enhances efficiency and practicality in both biomedical research and industrial applications.

Enhanced cellular viability and osteogenic activity in oxygen-self-generating and magnetically responsive alginate microgels as advanced cell carriers

Improving the accuracy of in vitro three-dimensional (3D) cellular cultures more closely replicates the in vivo microenvironment by mimicking the complex tissue structures, enhancing cell-cell interactions, and increasing differentiation potential along with functional capabilities. Natural materials aid in cell adhesion and proliferation within the 3D matrix, providing a more realistic growth environment. Oxygen availability is also critical for cell survival in 3D cultures, as a lack of oxygen can impede proliferation, reduce functionality, and ultimately result in cell death. To address the issue of oxygen supply in such systems, a novel magnetic alginate-based microcarrier that generates oxygen autonomously has been developed. This microcarrier contains calcium peroxide encapsulated within polylactic acid microspheres (CP), which act as an internal oxygen reservoir. The release of calcium ions results in weak interactions with alginate, thus improving structural integrity while also supporting bone marrow stromal cells (BMSCs) and creating a more in vivo-like microenvironment. Notably, when exposed to an external magnetic field, BMSCs on these CP/Fe3O4/SA microcarriers show improved viability, a marked decrease in hypoxia-inducible factor-1α (HIF-1α), and increased osteogenic gene expression. Therefore, the CP/Fe3O4/SA microcarriers represent a promising approach for enhancing in vitro 3D culture methods and offer significant potential for tissue repair and regeneration.

Assessment of In Vitro Models of the Human Buccal Mucosa for Vaccine and Adjuvant Development

To understand requirements for immunization via the oral mucosa, an in vitro model that recapitulates the physical barrier of the mouth, allows for quantification of antigen uptake and permeability and mounts an inflammatory response to antigen and adjuvant is needed. The physical structure of 4 models of the human oral mucosa was determined by histochemical staining and transepithelial electrical resistance (TEER) measurements. A TR146 based air-liquid interface (ALI) model most closely mimicked in vivo conditions. This was confirmed by validation studies using dextran and caffeine as diffusant molecules. Apparent permeability coefficients (Papp) of adenovirus (Ad) and adeno-associated virus (AAV) in this model were 4.3 × 10-13 and 2.2 × 10-10 respectively, while 100% of the total dose of H1N1 influenza remained in the epithelial layer. Sodium glycocholate and a hyperosmotic formulation improved the amount of Ad (p = 0.02) and AAV (p = 0.003) that entered the epithelium, respectively. Significant amounts of IL-6 (45.1 pg/mL), GM-CSF (94.7 pg/mL) and IFN-γ (4.3 pg/mL) were produced in response to influenza infection. Treatment with an AS03-like adjuvant induced production of IL-6 (34.9 pg/mL), TNF-∝ (43 pg/mL), GM-CSF (121.2 pg/mL) and IFN-γ (14.1 pg/mL). This highlights the contribution of differentiated epithelial cells to the immune response to vaccines and adjuvants.

A novel approach for engineering DHCM/GelMA microgels: application in hepatocellular carcinoma cell encapsulation and chemoresistance research

Liver cancer, a highly aggressive malignancy, continues to present significant challenges in therapeutic management due to its pronounced chemoresistance. This resistance, which undermines the efficacy of conventional chemotherapy and targeted therapies, is driven by multifaceted mechanisms, with increasing emphasis placed on the protective role of the tumor microenvironment (TME). The hepatocellular carcinoma extracellular matrix (ECM), a primary non-cellular component of the TME, has emerged as a critical regulator in cancer progression and drug resistance, particularly in hepatocellular carcinoma cell (HCC). In this study, a hybrid biomimetic hydrogel was engineered by integrating decellularized hepatocellular carcinoma matrix (DHCM) with gelatin methacrylate (GelMA) precursors. This composite DHCM/GelMA hydrogel was designed to replicate the physicochemical and functional properties of the hepatocellular carcinoma ECM, thereby offering a biomimetic platform to explore the interactions between HCCs and their microenvironment. Leveraging a custom-designed microfluidic 3D printing platform, we achieved high-throughput fabrication of HCC-encapsulated DHCM/GelMA microgels, characterized by enhanced uniformity, biocompatibility, and scalability. These microgels facilitated the construction of hepatocellular carcinoma microtissues, which were subsequently employed for chemoresistance studies. Our findings revealed that DHCM/GelMA microgels closely mimic the hepatocellular carcinoma tumor microenvironment, effectively recapitulating key features of ECM-mediated drug resistance. Mechanistic studies further demonstrated that DHCM significantly upregulates the expression of Aquaporin 3 (AQP3) in the encapsulated HCCs. This upregulation potentially activates mTOR signaling-associated autophagy pathways, thereby enhancing chemoresistance in HCCs. These biomimetic models provide a robust and versatile platform for studying the underlying mechanisms of drug resistance and evaluating therapeutic interventions. This innovative approach highlights the potential of DHCM/GelMA microgels as a transformative tool in cancer-associated tissue engineering and anticancer drug screening. By enabling detailed investigations into the role of ECM in chemoresistance, this study contributes to advancing therapeutic research and offers promising strategies to overcome drug resistance, ultimately improving clinical outcomes in liver cancer treatment.

Combining Top-Down and Bottom-Up: An Open Microfluidic Microtumor Model for Investigating Tumor Cell-ECM Interaction and Anti-Metastasis

Using a combined top-down (i.e., operator-directed) and bottom-up (i.e., cell-directed) strategy, an Under-oil Open Microfluidic System (UOMS)-based microtumor model is presented for investigating tumor cell migration and anti-metastasis drug test. Compared to the mainstream closed microfluidics-based microtumor models, the UOMS microtumor model features: i) micrometer-scale lateral resolution of surface patterning with open microfluidic design for flexible spatiotemporal sample manipulation (i.e., top-down); ii) self-organized extracellular matrix (ECM) structures and tumor cell-ECM spontaneous remodeling (i.e., bottom-up); and iii) free physical access to the samples on a device with minimized system disturbance. The UOMS microtumor model - allowing a controlled but also self-organized, cell-directed tumor-ECM microenvironment in an open microfluidic configuration - is used to test an anti-metastasis drug (incyclinide, aka CMT-3) with a triple-negative breast cancer cell line (MDA-MB-231). The in vitro results show a suppression of tumor cell migration and ECM remodeling echoing the in vivo mice metastasis results.

A cell-based drug screening assay on a centrifugal platform

Drug screening is an indispensable procedure in drug development and pharmaceutical research. For cell-based drug testing, cells were treated with compounds at different concentrations, and their responses were measured to assess the compounds' effects on cellular behavior. A concentration gradient test creates a growth environment with different compound concentrations for cultured cells, facilitating faster determination of the compound concentration's effect on cellular responses. However, most concentration gradient tests on cell cultures were carried out manually, which is labor-intensive and time-consuming. Microfluidic technology enables drug screening to be conducted in microstructures, which not only improves efficiency and sensitivity but also reduces reagent usage and operating time. Centrifugal microfluidics utilizes the rotation of a disk platform to perform complex fluid functions such as pumping, metering, and mixing. The complete process can be carried out with a low-cost motor without the need for an expensive pumping system. In this work, a centrifugal platform for drug screening is presented. The microfluidic platform can be divided into two parts. The inner disk features branch structures designed to establish a concentration gradient for cell growth. The outer ring contains fluidics for cell culturing, which can discharge the waste fluid when the nutrient is exhausted and replenish the new culture medium by spinning the platform. In conclusion, the proposed centrifugal platform can provide a rapid generation of the concentration gradients and automate the operation of cell culturing. It provides an efficient and low-cost platform for drug screening.

Applications of Artificial Intelligence, Deep Learning, and Machine Learning to Support the Analysis of Microscopic Images of Cells and Tissues

Artificial intelligence (AI) transforms image data analysis across many biomedical fields, such as cell biology, radiology, pathology, cancer biology, and immunology, with object detection, image feature extraction, classification, and segmentation applications. Advancements in deep learning (DL) research have been a critical factor in advancing computer techniques for biomedical image analysis and data mining. A significant improvement in the accuracy of cell detection and segmentation algorithms has been achieved as a result of the emergence of open-source software and innovative deep neural network architectures. Automated cell segmentation now enables the extraction of quantifiable cellular and spatial features from microscope images of cells and tissues, providing critical insights into cellular organization in various diseases. This review aims to examine the latest AI and DL techniques for cell analysis and data mining in microscopy images, aid the biologists who have less background knowledge in AI and machine learning (ML), and incorporate the ML models into microscopy focus images.

3D bioprinting for the construction of drug testing models-development strategies and regulatory concerns

A drug to be successfully launched in the market requires a significant amount of capital, resources and time, where the unsuccessful results in the last stages lead to catastrophic failure for discovering drugs. This is the very reason which calls for the invention of innovative models that can closely mimic the human in vivo model for producing reliable results. Throughout the innovation line, there has been improvement in the rationale in silico designing but yet there is requirement for in vitro-in vivo correlations. During the evolving of the drug testing models, the 3D models produced by different methods have been proven to produce better results than the traditional 2D models. However, the in vitro fabrications of live tissues are still bottleneck in realizing their complete potential. There is an urgent need for the development of single, standard and simplified in vitro 3D tissue models that can be reliable for investigating the biological and pathological aspects of drug discovery, which is yet to be achieved. The existing pre-clinical models have considerable drawbacks despite being the gold standard in pre-clinical research. The major drawback being the interspecies differences and low reliability on the generated results. This gap could be overcome by the fabrication of bioengineered human disease models for drug screening. The advancement in the fabrication of 3D models will provide a valuable tool in screening drugs at different stages as they are one step closer to bio-mimic human tissues. In this review, we have discussed on the evolution of preclinical studies, and different models, including mini tissues, spheroids, organoids, bioengineered three dimensional models and organs on chips. Furthermore, we provide details of different disease models fabricated across various organs and their applications. In addition to this, the review also focuses on the limitations and the current prospects of the role of three dimensionally bioprinted models in drug screening and development.

Nanoscale Cellular Traction Force Quantification: CRISPR-Cas12a Supercharged DNA Tension Sensors in Nanoclustered Ligand Patterns

High-throughput measurement of cellular traction forces at the nanoscale remains a significant challenge in mechanobiology, limiting our understanding of how cells interact with their microenvironment. Here, we present a novel technique for fabricating protein nanopatterns in standard multiwell microplate formats (96/384-wells), enabling the high-throughput quantification of cellular forces using DNA tension gauge tethers (TGTs) amplified by CRISPR-Cas12a. Our method employs sparse colloidal lithography to create nanopatterned surfaces with feature sizes ranging from sub 100 to 800 nm on transparent, planar, and fully PEGylated substrates. These surfaces allow for the orthogonal immobilization of two different proteins or biomolecules using click-chemistry, providing precise spatial control over cellular signaling cues. We demonstrate the robustness and versatility of this platform through imaging techniques, including total internal reflection fluorescence microscopy, confocal laser scanning microscopy, and high-throughput imaging. Applying this technology, we measured the early stage mechanical forces exerted by 3T3 fibroblasts across different nanoscale features, detecting forces ranging from 12 to 56 pN. By integrating the Mechano-Cas12a Assisted Tension Sensor (MCATS) system, we achieved rapid and high-throughput quantification of cellular traction forces, analyzing over 2 million cells within minutes. Our findings reveal that nanoscale clustering of integrin ligands significantly influences the mechanical responses of cells. This platform offers a powerful tool for mechanobiology research, facilitating the study of cellular forces and mechanotransduction pathways in a high-throughput manner compatible with standard cell culture systems.

Human brain organoids for understanding substance use disorders

Substance use disorders (SUDs) are complex mental health conditions involving a problematic pattern of substance use. Challenges remain in understanding its neural mechanisms, which are likely to lead to improved SUD treatments. Human brain organoids, brain-like 3D in vitro cultures derived from human stem cells, show unique potential in recapitulating the response of a developing human brain to substances. Here, we review the recent progress in understanding SUD using human brain organoid models focusing on neurodevelopmental perspectives. We first summarize the background of SUD in humans. Moreover, we introduce the development of various human brain organoid models and then discuss current progress and findings underlying the abuse of substances like nicotine, alcohol, and other addictive drugs using organoid models. Furthermore, we review efforts to develop organ chips and microphysiological systems to engineer better human brain organoids for advancing SUD studies. Lastly, we conclude by elaborating on the current challenges and future directions of SUD studies using human brain organoids.

Challenges in Humoral Immune Response to Adeno-Associated Viruses Determination

Adeno-associated viruses (AAVs) are non-pathogenic, replication-deficient viruses that have gained widespread attention for their application as gene therapy vectors. While these vectors offer high transduction efficiency and long-term gene expression, the host immune response poses a significant challenge to their clinical success. This review focuses on the obstacles to evaluating the humoral response to AAVs. We discuss the problems with the validation of in vitro tests and the possible approaches to overcome them. Using published data on neutralizing titers of AAV serotypes, we built the first antigenic maps of AAVs in order to visualize the antigenic relationships between varying serotypes.

Comprehensive Insights Into the Combinatorial Uses of Selected Phytochemicals in Colorectal Cancer Prevention and Treatment: Isothiocyanates, Quinones, Carotenoids, and Alkaloids

Despite the advancement in cancer diagnosis and treatment, colorectal cancer remains the leading cause of cancer-related death worldwide. Given the high recurrence rate of colorectal cancer even after surgical resection, chemotherapy has been clinically used to improve the treatment outcomes of colorectal cancer. However, chemotherapy is well-known for its toxic side effects. Thus, phytochemicals have been widely studied in recent years as preventive and therapeutic agents for colorectal cancer owing to their relatively low toxicity. Moreover, combinatorial uses of phytochemicals with other natural compounds or with drugs may amplify the positive outcomes of colorectal cancer prevention and treatment by intervening in multiple signaling pathways and targets. This review summarized the combinatorial use of several well-studied groups of phytochemicals, that is, isothiocyanates, quinones, carotenoids, and alkaloids, in the prevention and treatment of colorectal cancer, and suggested it as a potential approach to improve the anticancer efficacy of single compounds and minimize the toxic side effects associated with conventional drugs. Notably, we generalized the in vitro, in vivo, and clinical experiments-based molecular mechanisms whereby the selected phytochemicals in combination with other compounds exerted anti-colorectal cancer effects by inhibiting cancer cell proliferation, cell apoptosis, cell invasion, and tumor growth. Overall, this review provides a reference and new perspective to propel further advancements in research and development of preventative and therapeutic strategies for colorectal cancer.

Chaotic (bio)printing in the context of drug delivery systems

Chaotic (bio)printing, an innovative fabrication technique that uses chaotic flows to create highly ordered microstructures within materials, may be transformative for drug delivery systems. This review explores the principles underlying chaotic flows and their application in fabricating complex, multi-material constructs designed for advanced drug delivery and controlled release. Chaotic printing enables the precise layering of different active ingredients-a feature that may greatly facilitate the development of polypills with customizable release profiles. Recently, chaos-assisted fabrication has been extended to produce micro-architected hydrogel spheres in a high-throughput manner, potentially enhancing the versatility and efficiency of drug delivery methods. In addition, chaotic bioprinting enables the creation of evolved tissue models that more accurately emulate physiological systems, providing a more relevant platform for drug testing. This review also highlights the unique advantages of chaotic printing, including the ability to fabricate tissues with organized porosity and pre-vascularized structures, addressing critical challenges in tissue engineering. Despite its promising capabilities, challenges remain, particularly in expanding the range of materials compatible with chaotic printing. Continued research and development in this area are essential to fully realize the potential of chaotic (bio)printing in advancing drug delivery, paving the way for the next generation of smart drug delivery systems and functional tissue models for drug testing.

Analysis of chemosensitivity of tumor spheroids exposed to two-dimensional gradient of combination drugs in a hydrogel-based diffusion microfluidic platform

BACKGROUND

Liver cancer stands as a leading cause of cancer-related deaths globally, challenging conventional treatments due to resistance to chemotherapy and targeted therapy. Although frontline medications show initial efficacy, prolonged use often leads to resistance and harm. Current clinical strategies rely on combination therapies, but evaluating their effectiveness remains challenging.

RESULTS

To address this, we developed a hydrogel-based diffusion microfluidic platform for assessing chemosensitivity. This platform features a hydrogel-filled diffusion layer linked to liquid wells, allowing the creation of drug gradients. Tumor spheroids, cultured on the non-adhesive hydrogel surface, were exposed to single or combination drug gradients. Analysis revealed that drug efficacy, quantified by IC50 values, could be determined from responses to single drug gradients. A novel method was introduced to assess spheroid circularity as a time-invariant index of drug efficacy. Furthermore, exposing spheroids to 2D combination drug gradients allowed intuitive visualization of their responses via a color map. This analysis identified optimal drug combinations, exhibiting superior efficacy to monotherapy.

SIGNIFICANCE

The microfluidic platform enables assessment of synergistic effects and replicates in vivo conditions, enhancing the relevance of test results. By offering a streamlined, fast, and efficient drug screening approach, this platform aims to provide insight into tumor spheroid responses to varying drug combinations, facilitating more effective clinical applications.

All-aqueous synthesis of alginate complexed with fibrillated protein microcapsules for membrane-bounded culture of tumor spheroids

Water-in-water (W/W) emulsions provide bio-compatible all-aqueous compartments for artificial patterning and assembly of living cells. Successful entrapment of cells within a W/W emulsion via the formation of semipermeable capsules is a prerequisite for regulating on the size, shape, and architecture of cell aggregates. However, the high permeability and instability of the W/W interface, restricting the assembly of stable capsules, pose a fundamental challenge for cell entrapment. The current study addresses this problem by synthesizing multi-armed protein fibrils and controlling their assembly at the W/W interface. The multi-armed protein fibrils, also known as 'fibril clusters', were prepared by cross-linking lysozyme fibrils with multi-arm polyethylene glycol (PEG) via click chemistry. Compared to linear-structured fibrils, fibril clusters are strongly adsorbed at the W/W interface, forming an interconnected meshwork that better stabilizes the W/W emulsion. Moreover, when fibril clusters are complexed with alginate, the hybrid microcapsules demonstrate excellent mechanical robustness, semi-permeability, cytocompatibility and biodegradability. These advantages enable the encapsulation, entrapment and long-term culture of tumor spheroids, with great promise for applications for anti-cancer drug screening, tumor disease modeling, and tissue repair engineering.

Adipo-on-chip: a microphysiological system to culture human mesenchymal stem cells with improved adipogenic differentiation

Obesity is associated with several comorbidities that cause high mortality rates worldwide. Thus, the study of adipose tissue (AT) has become a target of high interest because of its crucial contribution to many metabolic diseases and metabolizing potential. However, many AT-related physiological, pathophysiological, and toxicological mechanisms in humans are still poorly understood, mainly due to the use of non-human animal models. Organ-on-chip (OoC) platform is a promising alternative to animal models. However, the use of adipose-derived human mesenchymal stem cells (hASCs) in these models is still scarce, and more knowledge on the effects properties of culturing hASCs in OoC models is needed. Here, we present the development of an OoC using hASCs to assess adipogenic differentiation. The device capability to increase hASC differentiation levels was confirmed by Nile red staining to verify lipid droplets inside cells after 10 days of culture and fluid flow of 10 µL/h. The Adipo-on-a-chip system increases hASC proliferation and differentiation area compared with the standard culture method under static conditions (96-well plates) verified in hASCs from different donors by image analysis of cells stained with Nile red. The expression of the gene FABP4 is lower in the MPS, which calls attention to different homeostasis and control of lipids in cells in the MPS, compared with the plates. An increase of hASC proliferation in the MPS related to the 96-well plate was verified through protein Ki-67 expression. Cell and nuclei morphology (area, roundness, perimeter, width, length, width to length rate, symmetry, compactness, axial and radial properties to nuclei, and texture) and dominant direction of cells inside the MPS were evaluated to characterize hASCs in the present model. The presented microphysiological system (MPS) provides a promising tool for applications in mechanistic research aiming to investigate adipogenesis in AT and toxicological assessment based on the hASC differentiation potential.

Using Label-Free Raman Spectroscopy Integrated with Microfluidic Chips to Probe Ferroptosis Networks in Cells

Ferroptosis, a regulated form of cell death driven by oxidative stress and lipid peroxidation, has emerged as a pivotal research focus with implications across various cellular contexts. In this study, we employed a multifaceted approach, integrating label-free Raman spectroscopy and microfluidics to study the mechanisms underpinning ferroptosis. Our investigations included the ferroptosis initiation based on the changes in the lipid Raman band at 1436 cm-1 under different cellular states, the generation of reactive oxygen species (ROS), lipid peroxidation, DNA damage/repair, and mitochondrial dysfunction. Importantly, our work highlighted the dynamic role of vital cellular components, such as nicotinamide adenine dinucleotide phosphate hydrogen (NADPH), ferredoxin clusters, and other key factors such as glutathione peroxidase 4 and nuclear factor erythroid 2, which collectively influenced cellular responses to redox imbalance and oxidative stress. Quantum mechanical (QM) and molecular docking simulations (MD) provided further evidence of interactions between the ferredoxin (containing 4Fe-4S clusters), NADPH, and ROS, which led to the production of reactive Fe species in the cells. As such, our approach not only offered a real-time, multidimensional perspective on ferroptosis but also provided valuable methods and insights for therapeutic interventions in diverse biomedical contexts.

A Systems Biology Approach Towards a Comprehensive Understanding of Ferroptosis

Ferroptosis is a regulated cell death process characterized by iron ion catalysis and reactive oxygen species, leading to lipid peroxidation. This mechanism plays a crucial role in age-related diseases, including cancer and cardiovascular and neurological disorders. To better mimic iron-induced cell death, predict the effects of various elements, and identify drugs capable of regulating ferroptosis, it is essential to develop precise models of this process. Such drugs can be tested on cellular models. Systems biology offers a powerful approach to studying biological processes through modeling, which involves accumulating and analyzing comprehensive research data. Once a model is created, it allows for examining the system's response to various stimuli. Our goal is to develop a modular framework for ferroptosis, enabling the prediction and screening of compounds with geroprotective and antiferroptotic effects. For modeling and analysis, we utilized BioUML (Biological Universal Modeling Language), which supports key standards in systems biology, modular and visual modeling, rapid simulation, parameter estimation, and a variety of numerical methods. This combination fulfills the requirements for modeling complex biological systems. The integrated modular model was validated on diverse datasets, including original experimental data. This framework encompasses essential molecular genetic processes such as the Fenton reaction, iron metabolism, lipid synthesis, and the antioxidant system. We identified structural relationships between molecular agents within each module and compared them to our proposed system for regulating the initiation and progression of ferroptosis. Our research highlights that no current models comprehensively cover all regulatory mechanisms of ferroptosis. By integrating data on ferroptosis modules into an integrated modular model, we can enhance our understanding of its mechanisms and assist in the discovery of new treatment targets for age-related diseases. A computational model of ferroptosis was developed based on a modular modeling approach and included 73 differential equations and 93 species.

Synthetic and natural polymer hydrogels: A review of 3D spheroids and drug delivery

This review centers on the synthesis and characterization of both natural and synthetic hydrogels, highlighting their diverse applications across various fields. We will delve into the evolution of hydrogels, focusing on the importance of polysaccharide-based and synthetic variants, which have been particularly chosen for 3D spheroid development in cancer research and drug delivery. A detailed background on the research and specific methodologies, including the in-situ free radical polymerization used for synthesizing these hydrogels, will be extensively discussed. Additionally, the review will explore various applications of these hydrogels, such as their self-healing properties, swelling ratios, pH responsiveness, and cell viability. A comprehensive literature review will support this investigation. Ultimately, this review aims to clearly outline the objectives and significance of hydrogel synthesis and their applications.

New Cellular Models to Support Preclinical Studies on ICAM-1-Targeted Drug Delivery

Intercellular adhesion molecule 1 (ICAM-1) is a cell-surface protein actively explored for targeted drug delivery. Anti-ICAM-1 nanocarriers (NCs) target ICAM-1-positive sites after intravenous injection in animal models, but quantitative mechanistic examination of cellular-level transport in vivo is not possible. Prior studies in human cell cultures indicated efficient uptake of these formulations via cell adhesion molecule-(CAM)-mediated endocytosis. However, ICAM-1 sequence differs among species; thus, whether anti-ICAM-1 NCs induce similar behavior in animal cells, key for intracellular drug delivery, is unknown. To begin bridging this gap, we first qualitatively verified intracellular transport of anti-ICAM-1 NCs in vivo and then developed new cellular models expressing ICAM-1 from mouse, dog, pig, and monkey, species relevant to pharmaceutical translation and veterinary medicine. ICAM-1 expression was verified by flow cytometry and confocal microscopy. These cells showed specific targeting compared to IgG NCs or cells treated with anti-ICAM-1 blocker. Anti-ICAM-1 NCs entered cells in a time- and temperature-dependent manner, with kinetics and pathway compatible with CAM-mediated endocytosis. All parameters tested were strikingly similar to those from human cells expressing ICAM-1 endogenously. Therefore, this new cellular platform represents a valuable tool that can be used in parallel to support in vivo studies on ICAM-1-targeted NCs during pharmaceutical translation.

Toolbox for creating three-dimensional liver models

Research within the hepato-biliary system and hepatic function is currently experiencing heightened interest, this is due to the high frequency of relapse rates observed in chronic conditions, as well as the imperative for the development of innovative therapeutic strategies to address both inherited and acquired diseases within this domain. The most commonly used sources for studying hepatocytes include primary human hepatocytes, human hepatic cancer cell lines, and hepatic-like cells derived from induced pluripotent stem cells. However, a significant challenge in primary hepatic cell culture is the rapid decline in their phenotypic characteristics, dedifferentiation and short cultivation time. This limitation creates various problems, including the inability to maintain long-term cell cultures, which can lead to failed experiments in drug development and the creation of relevant disease models for researchers' purposes. To address these issues, the creation of a powerful 3D cell model could play a pivotal role as a personalized disease model and help reduce the use of animal models during certain stages of research. Such a cell model could be used for disease modelling, genome editing, and drug discovery purposes. This review provides an overview of the main methods of 3D-culturing liver cells, including a discussion of their characteristics, advantages, and disadvantages.

Development of Advanced Oral-on-a-Chip: Replicating the Intricate Human Oral Microenvironment

The interactions between various cellular populations in the oral cavity, including gingival keratinocytes, tonsil-resident stem cells, periodontal ligament fibroblasts, and vascular endothelial cells, are crucial for maintaining oral health. These interactions regulate essential functions like tooth support and pathogen defense. However, conventional 2D and 3D in vitro models often fail to capture the complexity of these interactions and the multicellular architecture of the oral environment. To address this limitation, we developed an advanced 3D oral-on-a-chip system that mimics the dynamic microenvironment of oral tissues. This system incorporates multiple oral cells into a 3D structure made from natural polymers such as collagen and hyaluronic acid, crosslinked by blood-coagulating factors. Our study revealed that tonsil-resident stem cells are more sensitive to toxic exposure compared to differentiated cells like fibroblasts and endothelial cells. SERPINB2 was identified as a key biomarker of oral toxicity, with significant upregulation observed in tonsil-resident stem cells after exposure to toxins. Based on this, we developed a fluorescence-linked toxicity detection system using SERPINB2, enabling sensitive and quantitative assessments of oral toxicity. This integrated system provides a valuable tool for evaluating the oral toxicity of drug candidates.

Reversible bonding in thermoplastic elastomer microfluidic platforms for harvestable 3D microvessel networks

Transplantable ready-made microvessels have therapeutic potential for tissue regeneration and cell replacement therapy. Inspired by the natural rapid angiogenic sprouting of microvessels in vivo, engineered injectable 3D microvessel networks are created using thermoplastic elastomer (TPE) microfluidic devices. The TPE material used here is flexible, optically transparent, and can be robustly yet reversibly bonded to a variety of plastic substrates, making it a versatile choice for microfluidic device fabrication because it overcomes the weak self-adhesion properties and limited manufacturing options of poly(dimethylsiloxane) (PDMS). By leveraging the reversible bonding characteristics of TPE material templates, we present their utility as an organ-on-a-chip platform for forming and handling microvessel networks, and demonstrate their potential for animal-free tissue generation and transplantation in clinical applications. We first show that TPE-based devices have nearly 6-fold higher bonding strength during the cell culture step compared to PDMS-based devices while simultaneously maintaining a full reversible bond to (PS) culture plates, which are widely used for biological cell studies. We also demonstrate the successful generation of perfusable and interconnected 3D microvessel networks using TPE-PS microfluidic devices on both single and multi-vessel loading platforms. Importantly, after removing the TPE slab, microvessel networks remain intact on the PS substrate without any structural damage and can be effectively harvested following gel digestion. The TPE-based organ-on-a-chip platform offers substantial advantages by facilitating the harvesting procedure and maintaining the integrity of microfluidic-engineered microvessels for transplant. To the best of our knowledge, our TPE-based reversible bonding approach marks the first confirmation of successful retrieval of organ-specific vessel segments from the reversibly-bonded TPE microfluidic platform. We anticipate that the method will find applications in organ-on-a-chip and microphysiological system research, particularly in tissue analysis and vessel engraftment, where flexible and reversible bonding can be utilized.

A review: early detection of oral cancer biomarkers using microfluidic colorimetric point-of-care devices

Oral squamous cell carcinoma (OSCC) is the most common type of head and neck cancers. OSCC constitutes 90% of the head and neck malignancies. The delayed identification of oral cancer is the primary cause of ineffective medical treatment. To address this issue, low-cost, reliable point-of-care devices that can be utilized for large-scale screening, even in low-resource settings, including rural areas and primary healthcare centers, are of great interest. Herein, a comprehensive analysis of numerous salivary biomarkers that exhibit significant variations in concentration between individuals with oral cancer and those without is given. Furthermore, the article explores several point-of-care devices that exhibit potential in the realm of oral cancer detection. The biomarkers are discussed with a focus on their structural characteristics and role in oral cancer progression. The devices based on colorimetry and microfluidics are discussed in detail, considering their compliance with the 'REASSURED' criteria given by the World Health Organization (WHO) and suitability for mass screening in low-resource settings. Finally, the discourse revolves around the fundamental aspects pertaining to the advancement of multiplex, cost-effective point-of-care devices designed for widespread screening purposes.

Bioprinted Multi-Composition Array Mimicking Tumor Microenvironments to Evaluate Drug Efficacy with Multivariable Analysis

Current organ-on-a-chip technologies confront limitations in effectively recapitulating the intricate in vivo microenvironments and accommodating diverse experimental conditions on a single device. Here, a novel approach for constructing a multi-composition tumor array on a single microfluidic device, mimicking complex transport phenomena within tumor microenvironments (TMEs) and allowing for simultaneous evaluation of drug efficacy across 12 distinct conditions is presented. The TME array formed by bioprinting on a microfluidic substrate consists of 36 individual TME models, each characterized by one of three different compositions and tested under four varying drug concentrations. Notably, the TME model exhibits precise compartmentalization, fostering the development of self-organized vascular endothelial barriers surrounding breast cancer spheroids affecting substance transport. Multivariable screening and analysis of diverse conditions, including model complexity, replicates, and drug concentrations, within a single microfluidic platform, highlight the synergistic potential of integrating bioprinting with microfluidics to evaluate drug responses across diverse TME conditions comprehensively.

Enhanced hepatotoxicity assessment through encapsulated HepG2 spheroids in gelatin hydrogel matrices: Bridging the gap from 2D to 3D culture

Conventional 2D drug screening often fails to accurately predict clinical outcomes. We present an innovative approach to improve hepatotoxicity assessment by encapsulating HepG2 spheroids in gelatin hydrogel matrices with different mechanical properties. Encapsulated spheroids exhibit sustained liver-specific functionality, enhanced expression of drug-metabolizing enzymes, and increased drug sensitivity compared to 2D cultures. The platform detects critical variations in drug response, with significant differences in IC50 values between 2D and spheroid cultures ranging from 1.3-fold to > 13-fold, particularly for acetaminophen. Furthermore, drug-metabolizing enzyme expression varies across hydrogel concentrations, suggesting a role for matrix mechanical properties in modulating hepatocyte function. This novel spheroid-hydrogel platform offers a transformative approach to hepatotoxicity assessment, providing increased sensitivity, improved prediction, and a more physiologically relevant environment. The use of such advanced in vitro models can accelerate drug development, reduce animal testing, and contribute to improved patient safety and clinical outcomes.

Concave/Convex Curvature of Anisotropic Grooves Differentially Alters Cellular Morphology, Adhesion, and Proliferation

Curvature is an integral part of the complex in vivo tissue architecture across various length scales. Therefore, several in vitro models with a patterned curvature in different length scales have been developed to understand the role of this in cellular behavior. At the subcellular scale, wavy patterns have been reported wherein concave and convex grooves are adjacently present. However, the independent effect of continuous subcellular concave and convex shapes has not been reported, mainly owing to the limitations in fabricating such patterns. In this study, we developed continuous concave and convex grooves on polydimethylsiloxane (PDMS) using a Dracaena sanderiana (bamboo) leaf as a template. The first (negative) replica from the abaxial side of the bamboo leaf, which imparted concave grooves on PDMS, was subsequently used as a template to fabricate a positive replica of the leaf, resulting in convex grooves of the same size and arrangement as the concave grooves. We examined the influence of the groove curvature on the morphology of bone marrow-derived human mesenchymal stem cells (BM-hMSCs) and skeletal muscle cells (C2C12). BM-hMSCs and C2C12 cells aligned on both concave and convex grooves as compared to the random orientation on a flat substrate. The significant difference was observed in the morphology of both cells, in terms of area, aspect ratio, number, and length of protrusions on concave and convex patterns. We found that the number of protrusions was also dependent on the ratio of cell to pattern length scale for convex-shaped grooves but independent of length scale for concave-shaped grooves. The proliferation of BM-hMSCs was also found to be different on concave and convex shapes. Therefore, this study shows the importance of (1) convex and concave curvatures of the subcellular length scale in cellular response, (2) dependence on the ratio of cell and curvature length scale, and (3) use of natural templates for overcoming fabrication challenges.

Tape-assisted fabrication method for constructing PDMS membrane-containing culture devices with cyclic radial stretching stimulation

Advanced in vitro culture systems have emerged as alternatives to animal testing and traditional cell culture methods in biomedical research. Polydimethylsiloxane (PDMS) is frequently used in creating sophisticated culture devices owing to its elastomeric properties, which allow mechanical stretching to simulate physiological movements in cell experiments. We introduce a straightforward method that uses three types of commercial tape-generic, magic and masking-to fabricate PDMS membranes with microscale thicknesses (47.2 µm for generic, 58.1 µm for magic and 89.37 µm for masking) in these devices. These membranes are shaped as the bases of culture wells and can perform cyclic radial movements controlled via a vacuum system. In experiments with A549 cells under three mechanical stimulation conditions, we analysed transcriptional regulators responsive to external mechanical stimuli. Results indicated increased nuclear yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) activity in both confluent and densely packed cells under cyclically mechanical strains (Pearson's coefficient (PC) of 0.59 in confluent and 0.24 in dense cells) compared with static (PC = 0.47 in confluent and 0.13 in dense) and stretched conditions (PC = 0.55 in confluent and 0.20 in dense). This technique offers laboratories without microfabrication capabilities a viable option for exploring cellular behaviour under dynamic mechanical stimulation using PDMS membrane-equipped devices.

Human brain organoids for understanding substance use disorders

Substance use disorders (SUDs) are complex mental health conditions involving a problematic pattern of substance use. Challenges remain in understanding their neural mechanisms, which are likely to lead to improved SUD treatments. Human brain organoids, brain-like 3D in vitro cultures derived from human stem cells, show unique potential in recapitulating the response of a developing human brain to substances. Here, we review the recent progress in understanding SUDs using human brain organoid models focusing on neurodevelopmental perspectives. We first summarize the background of SUDs in humans. Moreover, we introduce the development of various human brain organoid models and then discuss current progress and findings underlying the abuse of substances like nicotine, alcohol, and other addictive drugs using organoid models. Furthermore, we review efforts to develop organ chips and microphysiological systems to engineer better human brain organoids for advancing SUD studies. Lastly, we conclude by elaborating on the current challenges and future directions of SUD studies using human brain organoids.

Artificial Intelligence-Based Microfluidic Platform for Detecting Contaminants in Water: A Review

Water pollution greatly impacts humans and ecosystems, so a series of policies have been enacted to control it. The first step in performing pollution control is to detect contaminants in the water. Various methods have been proposed for water quality testing, such as spectroscopy, chromatography, and electrochemical techniques. However, traditional testing methods require the utilization of laboratory equipment, which is large and not suitable for real-time testing in the field. Microfluidic devices can overcome the limitations of traditional testing instruments and have become an efficient and convenient tool for water quality analysis. At the same time, artificial intelligence is an ideal means of recognizing, classifying, and predicting data obtained from microfluidic systems. Microfluidic devices based on artificial intelligence and machine learning are being developed with great significance for the next generation of water quality monitoring systems. This review begins with a brief introduction to the algorithms involved in artificial intelligence and the materials used in the fabrication and detection techniques of microfluidic platforms. Then, the latest research development of combining the two for pollutant detection in water bodies, including heavy metals, pesticides, micro- and nanoplastics, and microalgae, is mainly introduced. Finally, the challenges encountered and the future directions of detection methods based on industrial intelligence and microfluidic chips are discussed.

Development of Cell Culture Platforms for Study of Trabecular Meshwork Cells and Glaucoma Development

BACKGROUND

Various cell culture platforms that could display native environmental cue-mimicking stimuli were developed, and effects of environmental cues on cell behaviors were studied with the cell culture platforms. Likewise, various cell culture platforms mimicking native trabecular meshwork (TM) composed of juxtacanalicular, corneoscleral and uveal meshwork located in internal scleral sulcus were used to study effects of environmental cues and/or drug treatments on TM cells and glaucoma development. Glaucoma is a disease that could cause blindness, and cause of glaucoma is not clearly identified yet. It appears that aqueous humor (AH) outflow resistance increased by damages on pathway of AH outflow can elevate intraocular pressure (IOP). These overall possibly contribute to development of glaucoma.

METHODS

For the study of glaucoma, static and dynamic cell culture platforms were developed. Particularly, the dynamic platforms exploiting AH outflow-mimicking perfusion or increased IOP-mimicking increased pressure were used to study how perfusion or increased pressure could affect TM cells. Overall, potential mechanisms of glaucoma development, TM structures and compositions, TM cell culture platform types and researches on TM cells and glaucoma development with the platforms were described in this review.

RESULTS AND CONCLUSION

This will be useful to improve researches on TM cells and develop enhanced therapies targeting glaucoma.

Advancing Point-of-Care Applications with Droplet Microfluidics: From Single-Cell to Multicellular Analysis

Recent advances in single-cell and multicellular microfluidics technology have provided powerful tools for studying cancer biology and immunology. The ability to create controlled microenvironments, perform high-throughput screenings, and monitor cellular interactions at the single-cell level has significantly advanced our understanding of tumor biology and immune responses. We discuss cutting-edge multicellular and single-cell microfluidic technologies and methodologies utilized to investigate cancer-immune cell interactions and assess the effectiveness of immunotherapies. We explore the advantages and limitations of the wide range of 3D spheroid and single-cell microfluidic models recently developed, highlighting the various approaches in device generation and applications in immunotherapy screening for potential opportunities for point-of-care approaches.

Advancing Tissue Culture with Light-Driven 3D-Printed Microfluidic Devices

Three-dimensional (3D) printing presents a compelling alternative for fabricating microfluidic devices, circumventing certain limitations associated with traditional soft lithography methods. Microfluidics play a crucial role in the biomedical sciences, particularly in the creation of tissue spheroids and pharmaceutical research. Among the various 3D printing techniques, light-driven methods such as stereolithography (SLA), digital light processing (DLP), and photopolymer inkjet printing have gained prominence in microfluidics due to their rapid prototyping capabilities, high-resolution printing, and low processing temperatures. This review offers a comprehensive overview of light-driven 3D printing techniques used in the fabrication of advanced microfluidic devices. It explores biomedical applications for 3D-printed microfluidics and provides insights into their potential impact and functionality within the biomedical field. We further summarize three light-driven 3D printing strategies for producing biomedical microfluidic systems: direct construction of microfluidic devices for cell culture, PDMS-based microfluidic devices for tissue engineering, and a modular SLA-printed microfluidic chip to co-culture and monitor cells.

Discarded CHO cells as a valuable source of bioactive peptides for sustainable biotechnological applications

Repurposing discarded cells stands as a groundbreaking paradigm shift in sustainable biotechnology, with profound implications across diverse industrial sectors. Our study proposes a transformative concept by harnessing histone proteins from discarded CHO cells to produce bioactive peptides. We systematically isolated and hydrolyzed histones using Trypsin and Neutrase enzymes, optimizing reaction conditions. Ultrafiltration yielded distinct peptide fractions (<3 kDa and 3-10 kDa), which we analyzed for DPP-IV inhibition, antioxidant potential, and other activities. Furthermore, LC-Q-TOF-MS analysis and in silico tools unveiled the structural composition of bioactive peptides within these fractions. Three peptide sequences with high bioactivity potential were identified: KLPFQR, VNRFLR, and LSSCAPVFL. Our findings demonstrated exceptional DPP-IV inhibition, potent antioxidant effects, and effective anti-lipid peroxidation activities, surpassing reference compounds. Hemolytic activity assessment indicated promising biocompatibility, enhancing therapeutic application prospects. Pioneering the strategic repurposing of discarded cells, this research addresses cost-efficiency in cell-based studies and promotes sustainable use of biological resources across sectors. This novel approach offers an efficient, eco-friendly method for bioactive molecule procurement and resource management, revolutionizing cell culture studies and biotechnological applications.

Advancing diagnostics and disease modeling: current concepts in biofabrication of soft microfluidic systems

Soft microfluidic systems play a pivotal role in personalized medicine, particularly in in vitro diagnostics tools and disease modeling. These systems offer unprecedented precision and versatility, enabling the creation of intricate three-dimensional (3D) tissue models that can closely emulate both physiological and pathophysiological conditions. By leveraging innovative biomaterials and bioinks, soft microfluidic systems can circumvent the current limitations involving the use of polydimethylsiloxane (PDMS), thus facilitating the development of customizable systems capable of sustaining the functions of encapsulated cells and mimicking complex biological microenvironments. The integration of lab-on-a-chip technologies with soft nanodevices further enhances disease models, paving the way for tailored therapeutic strategies. The current research concepts underscore the transformative potential of soft microfluidic systems, exemplified by recent breakthroughs in soft lithography and 3D (bio)printing. Novel applications, such as multi-layered tissues-on-chips and skin-on-a-chip devices, demonstrate significant advancements in disease modeling and personalized medicine. However, further exploration is warranted to address challenges in replicating intricate tissue structures while ensuring scalability and reproducibility. This exploration promises to drive innovation in biomedical research and healthcare, thus offering new insights and solutions to complex medical challenges and unmet needs.

Open and closed microfluidics for biosensing

Biosensing is vital for many areas like disease diagnosis, infectious disease prevention, and point-of-care monitoring. Microfluidics has been evidenced to be a powerful tool for biosensing via integrating biological detection processes into a palm-size chip. Based on the chip structure, microfluidics has two subdivision types: open microfluidics and closed microfluidics, whose operation methods would be diverse. In this review, we summarize fundamentals, liquid control methods, and applications of open and closed microfluidics separately, point out the bottlenecks, and propose potential directions of microfluidics-based biosensing.

Achieving Precision Healthcare through Nanomedicine and Enhanced Model Systems

The ability to customize medical choices according to an individual's genetic makeup and biomarker patterns marks a significant advancement toward overall improved healthcare for both individuals and society at large. By transitioning from the conventional one-size-fits-all approach to tailored treatments that can account for predispositions of different patient populations, nanomedicines can be customized to target the specific molecular underpinnings of a patient's disease, thus mitigating the risk of collateral damage. However, for these systems to reach their full potential, our understanding of how nano-based therapeutics behave within the intricate human body is necessary. Effective drug administration to the targeted organ or pathological niche is dictated by properties such as nanocarrier (NC) size, shape, and targeting abilities, where understanding how NCs change their properties when they encounter biomolecules and phenomena such as shear stress in flow remains a major challenge. This Review specifically focuses on vessel-on-a-chip technology that can provide increased understanding of NC behavior in blood and summarizes the specialized environment of the joint to showcase advanced tissue models as approaches to address translational challenges. Compared to conventional cell studies or animal models, these advanced models can integrate patient material for full customization. Combining such models with nanomedicine can contribute to making personalized medicine achievable.

Compact Micropatterned Chip Empowers Undisturbed and Programmable Drug Addition in High-Throughput Cell Screening

Simultaneously adding multiple drugs and other chemical reagents to individual droplets at specific time points presents a significant challenge, particularly when dealing with tiny droplets in high-throughput screening applications. In this study, a micropatterned polymer chip is developed as a miniaturized platform for light-induced programmable drug addition in cell-based screening. This chip incorporates a porous superhydrophobic polymer film with atom transfer radical polymerization reactivity, facilitating the efficient grafting of azobenzene methacrylate, a photoconformationally changeable group, onto the hydrophilic regions of polymer matrix at targeted locations and with precise densities. By employing light irradiation, the cyclodextrin-azobenzene host-guest complexes formed on the polymer chip can switch from an "associated" to a "dissociated" state, granting precise photochemical control over the supramolecular coding system and its surface patterning ability. Significantly, the exceptional spatial and temporal control offered by these chemical transitions empowers to utilize digital light processing systems for simultaneous regulation and release of cyclodextrin-bearing drugs across numerous droplets containing suspended or adhered cells. This approach minimizes mechanical disruption while achieving precise control over the timing of addition, dosage, and integration varieties of released drugs in high-throughput screening, all programmable to meet specific requirements.

Advances in screening hyperthermic nanomedicines in 3D tumor models

Hyperthermic nanomedicines are particularly relevant for tackling human cancer, providing a valuable alternative to conventional therapeutics. The early-stage preclinical performance evaluation of such anti-cancer treatments is conventionally performed in flat 2D cell cultures that do not mimic the volumetric heat transfer occurring in human tumors. Recently, improvements in bioengineered 3D in vitro models have unlocked the opportunity to recapitulate major tumor microenvironment hallmarks and generate highly informative readouts that can contribute to accelerating the discovery and validation of efficient hyperthermic treatments. Leveraging on this, herein we aim to showcase the potential of engineered physiomimetic 3D tumor models for evaluating the preclinical efficacy of hyperthermic nanomedicines, featuring the main advantages and design considerations under diverse testing scenarios. The most recent applications of 3D tumor models for screening photo- and/or magnetic nanomedicines will be discussed, either as standalone systems or in combinatorial approaches with other anti-cancer therapeutics. We envision that breakthroughs toward developing multi-functional 3D platforms for hyperthermia onset and follow-up will contribute to a more expedited discovery of top-performing hyperthermic therapies in a preclinical setting before their in vivo screening.

Advantages of Using 3D Spheroid Culture Systems in Toxicological and Pharmacological Assessment for Osteogenesis Research

Bone differentiation is crucial for skeletal development and maintenance. Its dysfunction can cause various pathological conditions such as rickets, osteoporosis, osteogenesis imperfecta, or Paget's disease. Although traditional two-dimensional cell culture systems have contributed significantly to our understanding of bone biology, they fail to replicate the intricate biotic environment of bone tissue. Three-dimensional (3D) spheroid cell cultures have gained widespread popularity for addressing bone defects. This review highlights the advantages of employing 3D culture systems to investigate bone differentiation. It highlights their capacity to mimic the complex in vivo environment and crucial cellular interactions pivotal to bone homeostasis. The exploration of 3D culture models in bone research offers enhanced physiological relevance, improved predictive capabilities, and reduced reliance on animal models, which have contributed to the advancement of safer and more effective strategies for drug development. Studies have highlighted the transformative potential of 3D culture systems for expanding our understanding of bone biology and developing targeted therapeutic interventions for bone-related disorders. This review explores how 3D culture systems have demonstrated promise in unraveling the intricate mechanisms governing bone homeostasis and responses to pharmacological agents.

Integrating mechanical cues with engineered platforms to explore cardiopulmonary development and disease

Mechanical forces provide critical biological signals to cells during healthy and aberrant organ development as well as during disease processes in adults. Within the cardiopulmonary system, mechanical forces, such as shear, compressive, and tensile forces, act across various length scales, and dysregulated forces are often a leading cause of disease initiation and progression such as in bronchopulmonary dysplasia and cardiomyopathies. Engineered in vitro models have supported studies of mechanical forces in a number of tissue and disease-specific contexts, thus enabling new mechanistic insights into cardiopulmonary development and disease. This review first provides fundamental examples where mechanical forces operate at multiple length scales to ensure precise lung and heart function. Next, we survey recent engineering platforms and tools that have provided new means to probe and modulate mechanical forces across in vitro and in vivo settings. Finally, the potential for interdisciplinary collaborations to inform novel therapeutic approaches for a number of cardiopulmonary diseases are discussed.

Recent Progress in Fabrication of Electrospun Nanofiber Membranes for Developing Physiological In Vitro Organ/Tissue Models

Nanofiber membranes (NFMs), which have an extracellular matrix-mimicking structure and unique physical properties, have garnered great attention as biomimetic materials for developing physiologically relevant in vitro organ/tissue models. Recent progress in NFM fabrication techniques immensely contributes to the development of NFM-based cell culture platforms for constructing physiological organ/tissue models. However, despite the significance of the NFM fabrication technique, an in-depth discussion of the fabrication technique and its future aspect is insufficient. This review provides an overview of the current state-of-the-art of NFM fabrication techniques from electrospinning techniques to postprocessing techniques for the fabrication of various types of NFM-based cell culture platforms. Moreover, the advantages of the NFM-based culture platforms in the construction of organ/tissue models are discussed especially for tissue barrier models, spheroids/organoids, and biomimetic organ/tissue constructs. Finally, the review concludes with perspectives on challenges and future directions for fabrication and utilization of NFMs.

Alternative Non-Mammalian Animal and Cellular Methods for the Study of Host-Fungal Interactions

In the study of fungal pathogenesis, alternative methods have gained prominence due to recent global legislation restricting the use of mammalian animals in research. The principle of the 3 Rs (replacement, reduction, and refinement) is integrated into regulations and guidelines governing animal experimentation in nearly all countries. This principle advocates substituting vertebrate animals with other invertebrate organisms, embryos, microorganisms, or cell cultures. This review addresses host-fungus interactions by employing three-dimensional (3D) cultures, which offer more faithful replication of the in vivo environment, and by utilizing alternative animal models to replace traditional mammals. Among these alternative models, species like Caenorhabditis elegans and Danio rerio share approximately 75% of their genes with humans. Furthermore, models such as Galleria mellonella and Tenebrio molitor demonstrate similarities in their innate immune systems as well as anatomical and physiological barriers, resembling those found in mammalian organisms.

Asymmetrical Obstacles Enable Unilateral Inertial Focusing and Separation in Sinusoidal Microchannel

Inertial microfluidics uses the intrinsic fluid inertia in confined channels to manipulate the particles and cells in a simple, high-throughput, and precise manner. Inertial focusing in a straight channel results in several equilibrium positions within the cross sections. Introducing channel curvature and adjusting the cross-sectional aspect ratio and shape can modify inertial focusing positions and can reduce the number of equilibrium positions. In this work, we introduce an innovative way to adjust the inertial focusing and reduce equilibrium positions by embedding asymmetrical obstacle microstructures. We demonstrated that asymmetrical concave obstacles could break the symmetry of original inertial focusing positions, resulting in unilateral focusing. In addition, we characterized the influence of obstacle size and 3 asymmetrical obstacle patterns on unilateral inertial focusing. Finally, we applied differential unilateral focusing on the separation of 10- and 15-μm particles and isolation of brain cancer cells (U87MG) from white blood cells (WBCs), respectively. The results indicated an excellent cancer cell recovery of 96.4% and WBC rejection ratio of 98.81%. After single processing, the purity of the cancer cells was dramatically enhanced from 1.01% to 90.13%, with an 89.24-fold enrichment. We believe that embedding asymmetric concave micro-obstacles is a new strategy to achieve unilateral inertial focusing and separation in curved channels.