Reprogrammable Magnetic Soft Actuators with Microfluidic Functional Modules via Pixel-Assembly.

Magnetic soft actuators and robots have attracted considerable attention in biomedical applications due to their speedy response, programmability, and biocompatibility. Despite recent advancements, the fabrication process of magnetic actuators and the reprogramming approach of their magnetization profiles continue to pose challenges. Here, a facile fabrication strategy is reported based on arrangements and distributions of reusable magnetic pixels on silicone substrates, allowing for various magnetic actuators with customizable architectures, arbitrary magnetization profiles, and integration of microfluidic technology. This approach enables intricate configurations with decent deformability and programmability, as well as biomimetic movements involving grasping, swimming, and wriggling in response to magnetic actuation. Moreover, microfluidic functional modules are integrated for various purposes, such as on/off valve control, curvature adjustment, fluid mixing, dynamic microfluidic architecture, and liquid delivery robot. The proposed method fulfills the requirements of low-cost, rapid, and simplified preparation of magnetic actuators, since it eliminates the need to sustain pre-defined deformations during the magnetization process or to employ laser heating or other stimulation for reprogramming the magnetization profile. Consequently, it is envisioned that magnetic actuators fabricated via pixel-assembly will have broad prospects in microfluidics and biomedical applications.

HMGCR inhibition stabilizes the glycolytic enzyme PKM2 to support the growth of renal cell carcinoma.

Renal cell carcinoma (RCC) is responsible for most cases of the kidney cancer. Previous research showed that low serum levels of cholesterol level positively correlate with poorer RCC-specific survival outcomes. However, the underlying mechanisms and functional significance of the role of cholesterol in the development of RCC remain obscure. 3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) plays a pivotal role in RCC development as it is the key rate-limiting enzyme of the cholesterol biosynthetic pathway. In this study, we demonstrated that the inhibition of HMGCR could accelerate the development of RCC tumors by lactate accumulation and angiogenesis in animal models. We identified that the inhibition of HMGCR led to an increase in glycolysis via the regulated HSP90 expression levels, thus maintaining the levels of a glycolysis rate-limiting enzyme, pyruvate kinase M2 (PKM2). Based on these findings, we reversed the HMGCR inhibition-induced tumor growth acceleration in RCC xenograft mice by suppressing glycolysis. Furthermore, the coadministration of Shikonin, a potent PKM2 inhibitor, reverted the tumor development induced by the HMGCR signaling pathway.

PCL scaffold combined with rat tail collagen type I to reduce keratocyte differentiation and prevent corneal stroma fibrosis after injury.

The cornea is one of the major refractive eye components and could be easily injured. An ineffective healing of corneal stromal wound may cause fibrosis and even loss of vision. Therefore, it is pivotal to prevent corneal fibrosis after injury. In this study, a poly (ε-caprolactone) (PCL) microfibrous scaffold infused with rat tail collagen type I was fabricated to obtain a 3D composite material. Physical and biological properties of PCL/collagen scaffold were evaluated, the effect of PCL/collagen scaffold on the proliferation and differentiation of limbal stromal stem cells (LSSCs) were detected in vitro, the differentiation of keratocytes as well as the expression and arrangement of extracellular matrix (ECM) influenced by PCL/collagen scaffold were investigated in vivo. RNA-sequencing on normal and injured corneas was carried out to find out the differential enriched pathways and gene expression. We discovered that the PCL/collagen scaffold simulated the stromal structure with properties that were most similar to the native cornea, the PCL/collagen scaffold exhibited good mechanical and biological properties. We also observed that the PCL/collagen scaffold reduced keratocyte differentiation. Injured corneas treated with PCL/collagen scaffold exhibited more regular collagen distribution and less fibroblasts and myofibroblasts distribution. By RNA-sequencing, we observed that in injured group, ECM-related pathway was enriched and several ECM-related genes were up-regulated. This study provides evidence that application of PCL/collagen scaffold could be a new therapeutic strategy for corneal injury.

Study on patterned photodynamic cross-linking for keratoconus.

PURPOSE: This study examined the patterned treatment of corneal collagen cross-linking (CXL) for keratoconus to reduce the complications caused by ultraviolet (UV) irradiation. By modifying the method of UV irradiation during the cross-linking process, cross-linking with a special structure is achieved, and the cross-linking effect is analyzed and compared to that of traditional cross-linking. By constructing an animal model of keratoconus, the process and effect of corneal cross-linking can be investigated more fundamentally. These studies provide valuable references for future cross-linking precision improvement and specialization. METHOD: By injecting exogenous collagenase into the corneal stroma of rabbits, the balance between collagenase and collagenase inhibitor in the corneal stroma was disrupted, the collagen fiber structure of the cornea was broken to simulate the pathogenesis of keratoconus, and an animal model of keratoconus was thus constructed. Two custom cross-linking patterns were designed with reference to the cable dome structure, and these two special patterns were irradiated and cross-linked by a DMD chip. The cross-linking effect was evaluated by optical coherence tomography (OCT), corneal topography and corneal biaxial tensile tests. The experimental rabbits were divided into four groups: group A, cross-linking of the bird's nest structure; group B, cross-linking of the honeycomb structure; group C, cross-linking of the traditional spot structure; and group D, normal (without modeling and cross-linking). RESULT: Following collagenase treatment, the collagen fiber structure of the rabbit cornea was destroyed, the central thickness of the cornea was reduced, the mechanical properties of the cornea were weakened, and no keratitis, ulcers or haze occurred. After the three cross-linking treatments, the morphology of the cornea improved, the density of the stromal layer increased, and the mechanical properties were enhanced. For the improvement of keratoconus mechanical properties, the average relative difference (Δ) of the four outcome measures was 61.98% for bird's nest cross-linking versus keratoconus (Wilcoxon rank sum test, P = 0.024), 16.13% for honeycomb cross-linking versus keratoconus (Wilcoxon rank sum test, P = 0.025), and 21.07% for traditional spot cross-linking versus keratoconus (Wilcoxon rank sum test, P = 0.014). All these differences are statistically significant. CONCLUSION: All three methods of cross-linking can improve the morphology and tissue structure of keratoconus and significantly improve the biomechanical properties of the cornea. Among them, the corneal cross-linking of the bird's nest structure attains the best biomechanical properties, followed by the corneal cross-linking of the traditional spot structure and of the honeycomb structure. This suggests that similar or better cross-linking effects can be achieved by designing custom structures with less UV exposure. This provides a direction for future research on better and more accurate pattern cross-linking treatments.

Stretch-driven microfluidic chip for nucleic acid detection.

Molecular diagnosis is an essential means to detect pathogens. The portable nucleic acid detection chip has excellent prospects in places where medical resources are scarce, and it is also of research interest in the field of microfluidic chips. Here, the article developed a new type of microfluidic chip for nucleic acid detection where stretching acts as the driving force. The sample entered the chip by applying capillary force. The strain valve was opened under the action of tensile force, and the spring pump generated the power to drive the fluid to flow to the detection chamber in a specific direction. The detection of coronavirus disease 2019 (COVID-19) was realized on the chip. The RT-LAMP amplification system was adopted to observe the liquid color in the detection chamber to decide whether the sample tested positive or negative qualitatively.

An integrated microfluidic detection system for the automated and rapid diagnosis of high-risk human papillomavirus.

Human papillomavirus (HPV) causes the prevalent sexually transmitted infection that accounts for the majority of cervical cancer incidences. Therefore, the development of a rapid, accurate, automatic and affordable nucleic acid detection strategy is urgently required for HPV tests, among which microfluidic chip is a promising diagnostic method. In this work, we developed a microfluidic detection system consisting of a microfluidic chip and the corresponding detection equipment to diagnose high-risk HPV. The proposed method integrates nucleic acid purification, isothermal amplification and real-time fluorescence detection into one device. Moreover, it demonstrates good detection performance such as high specificity of primer sets (100%) and exceptional stability (coefficient of variation <6%) among five HPV genotypes. Besides, the microfluidic loop-mediated isothermal amplification (LAMP) assay is accurate (specificity of 91.7% and sensitivity of 100%) and fast (average time threshold = 10.56 minutes) when considering the conventional qPCR assay as the gold standard. The integrated microfluidic detection system offers automated and rapid diagnosis within 40 minutes and shows broad potential to deliver point-of-care detection in resource-limited circumstances owing to its simplicity and affordability.

A core-skirt designed artificial cornea with orthogonal microfiber grid scaffold.

Artificial cornea is an effective treatment option for cases of severe corneal loss. In this study, we prepared a core-skirt designed artificial cornea with orthogonal microfiber grid scaffold. We fabricated PCL orthogonal microfiber grid scaffolds by a direct writing technique, and then combined them with compressed collagen (CC) to obtain a sandwich-like CC/P (where P is used to represent the PCL microfiber grid scaffold). PHEMA hydrogel and the CC/P served as the core and the skirt, respectively, with the P also serving as an intermediate between the two. The physical properties of the artificial cornea, including the morphology, the mechanical properties and the light transmittance, were evaluated. SEM images showed an effective connection and a lack of phase separation at the interface between the core and the skirt, and the skirt formed a highly porous scaffold that promoted tissue biointegration. In addition, we used the skirt structure to construct a corneal tissue model containing two cells types: corneal stromal stem cells (CSSCs) and mouse hippocampal neurons. The results showed that the cells could grow and differentiate well, and the orthogonal microfiber grid scaffold fibers were good guides for the structural growth of CSSCs and neuronal axons.

Three-dimensional microfluidic tumor-macrophage system for breast cancer cell invasion.

The recrudescence of breast cancer can partly be attributed to poor understanding of the early steps and the mechanisms involved in breast cancer metastasis, especially how tumor inflammatory cells including tumor-associated macrophages (TAM) affect invasion process. However, invasion-related biological studies in traditional in vitro assays or in vivo models are challenging due to the arduousness in establishing models that precisely reproduce the tumor invasion environment. To this end, we proposed a juxtaposed dual-layer cell-loaded hydrogels biomimetic microfluidic system and formed monolayer size-selective permeable vascular endothelial barriers besides the dual layer to mimic mammalian blood vessels. We clarified that in this system, TAM promoted the invasion of breast cancer cells, whereas breast cancer cells maintained the phenotype of TAM cells and promoted the differentiation of U937 cells into TAM. It formed a tumor-macrophage bidirectional crosstalk system. This system could be used for drug screening. So finally, through the calculation of the survival rate of breast cancer cells when cocultured with different macrophages under paclitaxel treatment, we analyzed the antagonism of tumor-macrophage bidirectional crosstalk on anticancer drugs.

The Boom in 3D-Printed Sensor Technology.

Future sensing applications will include high-performance features, such as toxin detection, real-time monitoring of physiological events, advanced diagnostics, and connected feedback. However, such multi-functional sensors require advancements in sensitivity, specificity, and throughput with the simultaneous delivery of multiple detection in a short time. Recent advances in 3D printing and electronics have brought us closer to sensors with multiplex advantages, and additive manufacturing approaches offer a new scope for sensor fabrication. To this end, we review the recent advances in 3D-printed cutting-edge sensors. These achievements demonstrate the successful application of 3D-printing technology in sensor fabrication, and the selected studies deeply explore the potential for creating sensors with higher performance. Further development of multi-process 3D printing is expected to expand future sensor utility and availability.

Multi-step PDMS curing and a controlled separation method for mass manufacturing of high-performance and user-friendly micro-devices: valved micropumps.

Although valved micropumps have powerful performance, their popularized application is limited by high technical barriers and high costs brought by complex microstructures. Herein, we propose a multi-step PDMS curing method and a local PDMS separation strategy to achieve mass, standardized, and low-cost manufacturing of valved micropumps, solving their popularized problems by promoting role separation between manufacturers and users. The multi-step curing and the centralized structural layout enable a volume 20 times smaller than other valved micropumps. The lithography mold quality is the main reason for only 74% yield, and using metal molds would be a better alternative. Theoretical analysis shows that the thickness and diameter of the pump membrane are the main factors in designing different driving capabilities of the micropump. By driving the micropump through periodic fluid pressure, the results show that the flow rate is positively related to the input pressure and exhibits two flow rate formation mechanisms at high and low frequencies. Its powerful back pressure generating ability also indicates that the micropump has wide application prospects as injection pumps. The micropump also demonstrates tremendous flexibility and convenience in integration, driving, and application. The multi-step PDMS curing and controlled separating ideas show popularization value for other microfluidic components, such as one-way valves, hoping to innovate the microfluidics field.

Programmable and resilient metamaterials with anisotropic and non-linear mechanical responses composed exclusively of stiff constituents.

Recently, significant progress has been made in the field of flexible bulk metamaterials composed of soft and elastic materials, unlocking the potential for achieving programmable non-linear mechanical responses, such as shape morphing, energy absorption, and information processing. However, the majority of these metamaterials utilize expensive hyperelastic materials and require complex fabrication processes. Additionally, constructing eco-friendly stiff constituents for these metamaterials remains challenging due to their limited elastic limit strains (<0.1). Here, we propose a systematic design strategy by combining curved beams with chiral metastructures to generate a family of three-dimensional programmable resilient mechanical metamaterials without relying on flexible or hyperelastic constituents. These tiled metamaterials demonstrate robust, anisotropic and non-linear resilience under large elastic compression strains (>0.75), while exhibiting a programmable effective modulus reduction of nearly 6 orders of magnitude compared to the native stiff components. Furthermore, leveraging their stable resilience under high-frequency stimuli, we successfully developed a meter-scale soft robot capable of traversing complex narrow scenarios on demand without the need for flexible materials or sophisticated pipelines. We anticipate that these mechanical metamaterials could serve as a universal platform for programmable active dampers, modular flexible robots, and medical rehabilitation equipment at various scales.

Integrated nucleic acid purification technology based on amino-modified centrifugal microfluidic chip.

Nucleic acid detection is an important tool for clinical diagnosis. The purification of the sample is the most time-consuming step in the nucleic acid testing process and will affect the results of the assay. Here, we developed a surface modification-based nucleic acid purification method and designed an accompanying set of centrifugation equipment and chips to integrate the steps of nucleic acid purification on a single platform. The results of experiments with HeLa cells and HPV type 16 as samples showed that the mentioned method had good nucleic acid purification capability and the accompanying equipment greatly simplified the operation of the experimenters in the whole process. Overall, our equipment can improve the efficiency of nucleic acid purification and is suitable for application in larger-scale clinical assays.

Oriented cellulose hydrogel: Directed tissue regeneration for reducing corneal leukoplakia and managing fungal corneal ulcers.

Fungal corneal ulcer is one of the leading causes of corneal blindness in developing countries. Corneal scars such as leukoplakia are formed due to inflammation, oxidative stress and non-directed repair, which seriously affect the patients' subsequent visual and life quality. In this study, drawing inspiration from the oriented structure of collagen fibers within the corneal stroma, we first proposed the directional arrangement of CuTA-CMHT hydrogel system at micro and macro scales based on the 3D printing extrusion method combined with secondary patterning. It played an antifungal role and induced oriented repair in therapy of fungal corneal ulcer. The results showed that it effectively inhibited Candida albicans, Aspergillus Niger, Fusarium sapropelum, which mainly affects TNF, NF-kappa B, and HIF-1 signaling pathways, achieving effective antifungal functions. More importantly, the fibroblasts interacted with extracellular matrix (ECM) of corneal stroma through formation of focal adhesions, promoted the proliferation and directional migration of cells in vitro, induced the directional alignment of collagen fibers and corneal stromal orthogonally oriented repair in vivo. This process is mainly associated with MYLK, MYL9, and ITGA3 molecules. Furthermore, the downregulation the growth factors TGF-ß and PDGF-ß inhibits myofibroblast development and reduces scar-type ECM production, thereby reducing corneal leukoplakia. It also activates the PI3K-AKT signaling pathway, promoting corneal healing. In conclusion, the oriented CuTA-CMHT hydrogel system mimics the orthogonal arrangement of collagen fibers, inhibits inflammation, eliminates reactive oxygen species, and reduces corneal leukoplakia, which is of great significance in the treatment of fungal corneal ulcer and is expected to write a new chapter in corneal tissue engineering.

Bioprinted, spatially defined breast tumor microenvironment models of intratumoral heterogeneity and drug resistance.

Cellular, extracellular matrix (ECM), and spatial heterogeneity of tumor microenvironments (TMEs) regulate disease progression and treatment efficacy. Developing in vitro models that recapitulate the TME promises to accelerate studies of tumor biology and identify new targets for therapy. Here, we used extrusion-based, multi-nozzle 3D bioprinting to spatially pattern triple-negative MDA-MB-231 breast cancer cells, endothelial cells (ECs), and human mammary cancer-associated fibroblasts (HMCAFs) with biomimetic ECM inks. Bioprinted models captured key features of the spatial architecture of human breast tumors, including varying-sized dense regions of cancer cells and surrounding microvessel-rich stroma. Angiogenesis and ECM stiffening occurred in the stromal area but not the cancer cell-rich (CCR) regions, mimicking pathological changes in patient samples. Transcriptomic analyses revealed upregulation of angiogenesis-related and ECM remodeling-related signatures in the stroma region and identified potential ligand-receptor (LR) mediators of these processes. Breast cancer cells in distinct parts of the bioprinted TME showed differing sensitivities to chemotherapy, highlighting environmentally mediated drug resistance. In summary, our 3D-bioprinted tumor model will act as a platform to discover integrated functions of the TME in cancer biology and therapy.

Magnetically Driven Modular Mechanical Metamaterials with High Programmability, Reconfigurability, and Multiple Applications.

Shape transformation and motion guidance are emerging research hotspots of mechanical metamaterials. In this case, the key issue is how to improve the programmability and reconfigurability of metamaterials. The magnetically driven method enables materials to accomplish remote, fast, and reversible deformation, so it is desired for improving the programmability and reconfigurability of metamaterials. However, conventional magnetically driven materials are often pure elastomer materials. Their magnetic programming method is single, and their overall shape is unchangeable after fabrication, which limits their programmability and reconfigurability. Herein, this article proposes a kind of magnetically driven, programmable, and reconfigurable modular mechanical metamaterial based on origami and kirigami design mechanisms. The motion and deformation were designed to follow the predefined creases and incisions that could be transformed into each other. This metamaterial enabled more discrete motion and force transmission and integrated the fold of origami, the rotation of kirigami, and the fold guided by cuts. Such designs laid the foundation for complex, three-dimensional structures which could be quickly reassembled and constructed to deal with complex situations. This paper also demonstrated applications of this metamaterial in information storage and manifestation, mechanical logic computing, reconfigurable robotics, deployable mechanisms, and so on. The results indicated that the high programmability and reconfigurability expanded the application potential of the metamaterial for broader needs.

Modular design of curved beam-based recyclable architected materials.

Advances in manufacturing technologies have enabled architected materials with unprecedented properties. These materials are typically irreversibly designed and fabricated with characteristic geometries and specific mechanical properties, thus rendering them suitable for pre-specified requests. However, these materials cannot be recycled or reconstructed into different shapes and functionalities to economically adapt to various environments. Hence, we present a modular design strategy to create a category of recyclable architected materials comprising elastic initially curved beams and rigid cylindrical magnets. Based on numerical analyses and physical prototypes, we introduce an arc-serpentine curved beam (ASCB) and systematically investigate its mechanical properties. Subsequently, we develop two sets of hierarchical modules for the ASCB, thus expanding the constructable shape of architected materials from regular cuboids to complex curved surfaces. Furthermore, we demonstrate that the magnets attached to the centers of specific serpentine patterns of the modules allows the effective in-situ recycling of the designed materials, including sheet materials for non-damage storage, bulk materials for tunable stiffness, and protective package boxes for reshaping into decorative lampshades. We expect our approach to improve the flexibility of architected materials for multifunctional implementation in resource-limited scenarios.

Variable-position centrifugal platform achieves droplet manipulation and logic circuitries on-chip.

Taking information as material to realize non-electronic physical computing is a promising idea, which facilitates the integration of technologies in different fields such as chemistry, biology, and mechanical control into a new computing platform. Here, we propose a novel, efficient and robust manipulation platform that drives droplet computing by way of inertial force. Combining this with droplet flow path design, we demonstrated multiple basic functions of droplet manipulation, including storage, dosing, interrupts, controllable release and addressing. These basic functions without external control lay the foundation for the realization of droplet calculation. We developed AND, OR, and XOR logic gates of the "liquid circuit" and combined them into a binary adder, which successfully completed the addition of four-digit binary numbers through droplet movement. Moreover, we attempted to perform algorithmic design for biological information under the control of droplets based on synchronous logical operations, developing the possibility of biological applications. This programmable physical computing system exists independently of electronic computing, aiming to supplement and expand the computing methods outside the field of electronic technology and to open a new method for the algorithmic operation of materials after combining new physical computing technologies such as biological or chemical computing.

Research of restricted migration evaluation of MDA-MB-231 cells in 2D and 3D co-culture models.

The restricted migration evaluation is conducive to more complex tumor migration research because of the conformity with in vivo tumors. However, the differences between restricted and unrestricted cell migration and the distinction between different evaluation methods have not been systematically studied, hindering related research. In this study, by constructing the restricted environments on chips, the influence of co-culture conditions on the cancer cell migration capacity was studied. The results showed that the restricted channels can discriminate the influence of weak tumor environmental factors on complex tumor migration behaviors by limiting the free growth instinct of tumor cells. Through the comparison of 2D and 3D restricted migration methods, the extracellular matrix (ECM) restriction was also helpful in distinguishing the influence of the weak tumor environmental factor. However, the 3D ECM can better reflect the tortuosity of the cell migration process and the cooperative behavior among cancer cells. In the anticancer drug evaluation, 3D ECM can more accurately reflect the cytotoxicity of drugs and is more consistent with the drug resistance in the human body. In conclusion, the research will help to distinguish different evaluation methods of cancer cell migration, help researchers select appropriate evaluation models, and promote the research of tumor metastasis.

Apolipoprotein A-IV of diabetic-foot patients upregulates tumor necrosis factor α expression in microfluidic arterial models.

Diabetic peripheral arterial atherosclerosis is one of the important characteristics of diabetic foot syndrome. Apolipoprotein (Apo A-IV) participates in various physiological processes, and animal studies have shown that it has roles of anti-atherosclerosis, prevention of platelet aggregation and thrombosis. Apo A-IV glycosylation is closely related to the occurrence and development of diabetic peripheral atherosclerosis. This study aimed to explore the mechanism of diabetic peripheral arterial lesions caused by glycosylated Apo A-IV. Type 2 diabetes mellitus (T2DM) and T2DM with diabetic foot patients (T2DM-F; n = 45, 30) were enrolled in this study, and individuals without diabetes (n = 35) served as normal controls (NC). In T2DM group, serum Apo A-IV content was higher than those in NC and T2DM-F group, as carboxymethyl lysine (CML) glycosylation of Apo A-IV in mixed serum from T2DM-F group was identified to be more significant than those in two other groups. Within a microfluidic arterial chip model, Apo A-IV from T2DM and T2DM-F group significantly increased transcription and protein levels of tumor necrosis factor alpha (TNF-α) in chip arteries, and CML expression was observed in T2DM-F group, which were associated with increased nuclear receptor subfamily 4 group A member 3 (NR4A3) expression. Recombinant human Apo A-IV could reverse the stimulating effect of serum Apo A-IV from T2DM-F group on TNF-α expression, and NR4A3 blocking peptide downregulated TNF-α expression by inhibiting NR4A3 expression. In the chip arteries, Apo A-IV from T2DM and T2DM-F increased TNF-α expression and turn them into a pre-atherosclerotic state, which might be one of the important mechanisms of glycosylated Apo A-IV to induce diabetic peripheral arterial lesions and eventually lead to diabetic foot.

Biofabrication of Composite Tendon Constructs with the Fibrous Arrangement, High Cell Density, and Enhanced Cell Alignment.

Current tissue-engineered tendons are mostly limited to the replication of fibrous organizations of native tendons, which lack the biomimicry of a densely packed cell arrangement. In this study, composite tendon constructs (CTCs) with fibrous arrangement, high cell density, and enhanced cell alignment were developed by integrating the electrohydrodynamic jet 3D printing (e-jetting) technique and the fabrication of tissue strands (TSs). A tubular polycaprolactone (PCL) scaffold was created using e-jetting, followed by coating a thin layer of alginate. Human mesenchymal stem cells were then microinjected into the PCL scaffolds, aggregated into TSs, and formed CTCs with a core-shell structure. Owing to the presence of TSs, CTCs demonstrated the anatomically relevant cell density and morphology, and cells migrated from the TSs onto e-jetted scaffolds. Also, the mechanical strength of CTCs approached that of native tendons due to the existence of e-jetted scaffolds (Young's modulus: ∼21 MPa, ultimate strength: ∼5 MPa). During the entire culture period, CTCs maintained high survival rates and good structural integrity without the observation of necrotic cores and disintegration of two portions. In addition, CTCs that were cultured with uniaxial cyclic stretching revealed not only the increased expression of tendon-related proteins but also the enhanced cellular orientation. The promising results demonstrated the potential of this novel biofabrication strategy for building tissue-engineered tendon constructs with the proper biological, mechanical, and histological relevance..