Ting-Yuan Tu

Metastatic invasiveness emerges from coordinated intrinsic programs and microenvironmental cues that converge on mitochondrial quality control (MQC). Here, we use “context” to denote stage‐ and site‐aware constellations of tumor‐intrinsic states (e.g., mtROS tone, mtDNA integrity, epigenetic wiring, cellular stiffness, oncogenic mutations) and extrinsic landscapes (oxygen–nutrient availability, ECM mechanics, stromal/inflammatory signals). These axes jointly shape mitochondrial adaptation by tuning bioenergetics, redox balance, metabolic plasticity, fission–fusion dynamics, mechanosensitive hubs, and Ca ^{2 +} homeostasis. As pressures intensify, mitochondrial vulnerabilities—such as mtDNA compromise and mtUPR activation—signal the engagement of mitophagy to preserve organelle fitness under stress. Through these coupled changes in mitochondrial performance and stress responses, context governs EMT/MET plasticity and transitions across migratory, invasive, and proliferative states. Mechanistically, ubiquitin conjugation, via E3 ligases and deubiquitinases, serves as an integrating conduit that links mitochondrial remodeling and mitophagy to cytoskeletal reprogramming and invasive behavior. This ubiquitin–mitochondria interface therefore represents a coherent therapeutic entry point; translational strategies including PROTAC‐enabled targeting and selective E3/DUB or mitophagy‐pathway modulators may rebalance pathological ubiquitin signaling, restore mitochondrial homeostasis, and constrain tumor dissemination.

Hierarchical extracellular matrix (ECM) cues spanning mechanics, architecture, and matrix–matrix interfaces (MMIs) regulate the directionality and efficiency of tumor-cell migration and invasion. Despite their relevance, the contributions of interfacial structures within 3D ECMs remain under-resolved, particularly whether discrete boundaries serve as “attractor-and-track” drivers. Here, we engineered a polydimethylsiloxane (PDMS) microfluidic platform to create controlled MMIs that emulate the tumor microenvironment (TME)’s mechanical heterogeneity, achieved by sequential collagen gelation to create both planar and curved boundaries. With the system, we quantified how MDA-MB-231 (invasive) and MCF-7 (non-invasive) breast cancer spheroids migrate in uniform matrices of graded stiffness and when encountering soft–stiff boundaries. MDA-MB-231 spheroids demonstrated significantly greater migration in soft matrices and exhibited distinct invasive outgrowth at interfacial boundaries, with soft-top pairings (o–o, t–o) gating early detachment, followed by convergence of outgrowth across stiffness pairings at later times. Spheroids positioned above or below planar or curved MMIs showed directional approach toward the boundary and alignment of trajectories within the interfacial plane, consistent with interface-seeking and interface-parallel migration. In contrast, MCF-7 spheroids displayed minimal migration under all tested conditions, underscoring a phenotype-dependent responsiveness to ECM cues. Overall, our findings highlight the critical role of interfacial structures, in addition to bulk stiffness and architecture, in shaping cancer invasion, supporting a two-phase model in which local bulk mechanics license early outward dissemination, whereas interfacial stiffness increasingly sustains expansion. The proposed microfluidic platform offers a tunable and physiologically relevant model for dissecting 3D cell migration mechanisms within complex ECM environments, with optical access, curvature control, and validated passive gradients enabling future chemotaxis studies.

Traditional monolithic microfluidic devices are constrained by their inability to accommodate modifications to circuit elements, necessitating complete redesign and refabrication. To address these limitations, this study introduces modular microfluidic connectors fabricated via stereolithographic (SL) 3D printing. We designed and evaluated three distinct connector types––tessellated, sponge, and solid-walled––using tailored photoresins to enhance reusability, flexibility, and sealing performance. The tessellated connectors, printed with poly(ethylene glycol) diacrylate (PEGDA, Mw ~258) and incorporating an Octet Unit cell structure, reduced the rigidity of PEGDA prints, improving reusability under moderate conditions. The sponge connectors, fabricated from a PEGDA and 2-hydroxyethyl acrylate (2-HEA, Mw ~ 116) blend (2-HEA-co-PEGDA), exhibited greater flexibility; however, swelling in aqueous environments may limit their long-term utility. In contrast, the solid-walled connectors, produced with commercial Asiga Soft Resin, demonstrated superior reliability and adaptability, as validated in a reconfigurable concentration gradient generator (CGG) with scalable output capabilities. Cytocompatibility tests confirmed that PEGDA-printed devices, following isopropanol (IPA) and UV post-processing, are suitable for bioanalytical applications that do not require incubation. These findings establish SL 3D printing as a promising method for developing flexible, reconfigurable microfluidic platforms, with potential uses in material synthesis, chemical analysis, and point-of-care diagnostics. While challenges related to environmental durability persist, these advances lay the foundations for developing more robust and adaptable microfluidic systems with versatile applications.

Background: Previous studies have suggested that changes in the composition of the extracellular matrix (ECM) play a significant role in the development of ligamentum flavum hypertrophy (LFH) and the histological differences between the ventral and dorsal layers of the hypertrophied ligamentum flavum. Although LFH is associated with increased fibrosis in the dorsal layer, comprehensive research exploring the characteristics of the ECM and its mechanical properties in both regions is limited. Furthermore, the distribution of fibrosis‐associated myofibroblasts within LFH remains poorly understood. This study aimed to bridge the existing knowledge gap concerning the intricate relationships between ECM characteristics, mechanical properties, and myofibroblast expression in LFH.Methods: Histological staining, scanning electron microscopy, and atomic force microscopy were used to analyze the components, alignment, and mechanical properties of the ECM. Immunostaining and western blot analyses were performed to assess the distribution of myofibroblasts in LF tissues.Results: There were notable differences between the dorsal and ventral layers of the hypertrophic ligamentum flavum. Specifically, the dorsal layer exhibited higher collagen content and disorganized fibrous alignment, resulting in reduced stiffness. Immunohistochemistry analysis revealed a significantly greater presence of α‐smooth muscle actin (αSMA)‐stained cells, a marker for myofibroblasts, in the dorsal layer.Conclusions: This study offers comprehensive insights into LFH by elucidating the distinctive ECM characteristics, mechanical properties, and cellular composition disparities between the ventral and dorsal layers. These findings significantly enhance our understanding of the pathogenesis of LFH and may inform future research and therapeutic strategies.

Flow-based particle separation usually requires a sheath flow for particle manipulation. Sheath fluid is a specialized buffer solution that directs the alignment of particles or cells into the center of the stream. By utilizing sheath flow, the particles or cells can be focused on the middle line of the microchannel, where they can be individually analyzed. However, the method requires an additional design for creating a suitable sheath flow. Purity and separation efficiency may also be influenced by the sheath flow. In this study, we present a sheathless device for particle focusing and separation using standing surface acoustic waves (SSAWs). The device comprises two regions: the focusing and separation regions. In the focusing region, particles in a continuous flow are aligned in the middle of the microchannel by SSAWs; in the separation region, tilted-angle SSAW-based particle separation is used to control particle migration. Varying particle sizes were focused in the focusing region and then separated in the separation region in the sheathless device. Experiments and simulations were also utilized to optimize a sheathless device. 10 and 20 μm particle focusing and separation were conducted in a sheathless device for the first time. We demonstrate that the separation of particles with a diameter of 10 and 20 μm has 90.8 ± 1.75% and 99.5 ± 0.8% separation efficiency, and 98 ± 3.4 and 97.9 ± 0.9% purity. Compared with other focusing and separation technologies, our device can also provide high purity, high separation efficiency, and high device density.

Interbody fusion is an orthopedic surgical procedure to connect two adjacent vertebrae in patients suffering from spinal disc disease. The combination of synthetic bone grafts with protein-based drugs is an intriguing approach to stimulate interbody bone growth, specifically in patients exhibiting restricted bone progression. Recombinant human thrombomodulin (rhTM), a novel protein drug characterized by its superior stability and potency, shows promise in enhancing bone formation. A composite bone graft, termed CaP-rhTM, has been synthesized, combining calcium phosphate (CaP) microparticles as a delivery vehicle for rhTM to facilitate interbody fusion. In vitro studies have demonstrated that rhTM significantly promotes the proliferation and maturation of preosteoblasts at nanogram dosage, while exerting minimal impact on osteosarcoma cell growth. The expression levels of mature osteoblast markers, including osteocalcin, osteopontin, alkaline phosphatase, and calcium deposition were also enhanced by rhTM. In rat caudal disc model of interbody fusion, CaP-rhTM with 800 ng of drug dosage was implanted along with a polylactic acid cage, to ensure structural stability within the intervertebral space. Microcomputed tomography analyses revealed that from 8 to 24 weeks, CaP-rhTM substantially improves both bone volume and trabecular architecture, in addition to the textural integrity of bony endplate surfaces. Histological examination confirmed the formation of a continuous bone bridge connecting adjacent vertebrae. Furthermore, biomechanical assessment via three-point bending tests indicated an improved bone quality of the fused disc. This study has demostrated that rhTM exhibits considerable potential in promoting osteogenesis. The use of CaP-rhTM has also shown significant improvements in promoting interbody fusion.

Collagen is an important material for biomedical research, but using mammalian tissue-derived collagen carries the risk of zoonotic disease transmission. Marine organisms, such as farmed tilapia, have emerged as a safe alternative source of collagen for biomedical research. However, the tilapia collagen products for biomedical research are rare, and their biological functions remain largely unexamined. In this study, we characterized a commercial tilapia skin collagen using SDS-PAGE and fibril formation assays and evaluated its effects on skin fibroblast adhesion, proliferation, and migration, comparing it with commercial collagen from rat tails, porcine skin, and bovine skin. The results showed that tilapia skin collagen is a type I collagen, similar to rat tail collagen, and has a faster fibril formation rate and better-promoting effects on cell migration than porcine and bovine skin collagen. We also confirmed its application in a 3D culture for kidney cells’ spherical cyst formation, fibroblast-induced gel contraction, and tumor spheroid interfacial invasion. Furthermore, we demonstrated that the freeze-dried tilapia skin collagen scaffold improved wound closure in a mouse excisional wound model, similar to commercial porcine or bovine collagen wound dressings. In conclusion, tilapia skin collagen is an ideal biomaterial for biomedical research.