Magnetically driven formation of 3D freestanding soft bioscaffolds.

3D soft bioscaffolds have great promise in tissue engineering, biohybrid robotics, and organ-on-a-chip engineering applications. Though emerging three-dimensional (3D) printing techniques offer versatility for assembling soft biomaterials, challenges persist in overcoming the deformation or collapse of delicate 3D structures during fabrication, especially for overhanging or thin features. This study introduces a magnet-assisted fabrication strategy that uses a magnetic field to trigger shape morphing and provide remote temporary support, enabling the straightforward creation of soft bioscaffolds with overhangs and thin-walled structures in 3D. We demonstrate the versatility and effectiveness of our strategy through the fabrication of bioscaffolds that replicate the complex 3D topology of branching vascular systems. Furthermore, we engineered hydrogel-based bioscaffolds to support biohybrid soft actuators capable of walking motion triggered by cardiomyocytes. This approach opens new possibilities for shaping hydrogel materials into complex 3D morphologies, which will further empower a broad range of biomedical applications.

A specific RAGE-binding peptide inhibits triple negative breast cancer growth through blocking of Erk1/2/NF-κB pathway.

Triple-negative breast cancer (TNBC) is an aggressive cancer that poses a significant threat to women's health. Unfortunately, the lack of clinical targets leads the poor clinical outcomes in TNBC. Many cancers demonstrate overexpression of receptor for advanced glycation end products (RAGE), which can contribute to cancer progression. Despite the potential therapeutic value of blocking RAGE for TNBC treatment, effective peptide drugs have yet to be developed. In our study, we observed that RAGE was highly expressed in TNBC and was associated with poor disease progression. We subsequently investigated the antitumor effects and underlying mechanisms of the RAGE antagonist peptide RP7 in both in vitro and in vivo models of TNBC. Our study revealed that RP7 selectively binds to RAGE-overexpressing TNBC cell lines, including MDA-MB-231 and BT549, and significantly inhibits cell viability, migration, and invasion in both cell lines. Furthermore, RP7-treatment suppressed tumor growth in TNBC xenograft mouse models without inducing detectable toxicity in normal tissues. Mechanistically, RP7 was found to inhibit the phosphorylation of ERK1/2, IKKα/ß, IKBα, and p65 to block the NF-κB pathway, prevent the entry of p65 into the nucleus, decrease the protein expression of Bcl-2 and HMGB1, and promote the release of cytochrome C from the mitochondria into the cytoplasm. These effects were observed to activate apoptosis and inhibit epithelial-mesenchymal transition (EMT) in TNBC cells. This study highlights RAGE as a candidate therapeutic target for TNBC treatment and suggests that the RAGE antagonist peptide RP7 is a promising anticancer drug for TNBC.

Bead-jet printing enabled sparse mesenchymal stem cell patterning augments skeletal muscle and hair follicle regeneration.

Transplantation of mesenchymal stem cells (MSCs) holds promise to repair severe traumatic injuries. However, current transplantation practices limit the potential of this technique, either by losing the viable MSCs or reducing the performance of resident MSCs. Herein, we design a "bead-jet" printer, specialized for high-throughput intra-operative formulation and printing of MSCs-laden Matrigel beads. We show that high-density encapsulation of MSCs in Matrigel beads is able to augment MSC function, increasing MSC proliferation, migration, and extracellular vesicle production, compared with low-density bead or high-density bulk encapsulation of the equivalent number of MSCs. We find that the high-density MSCs-laden beads in sparse patterns demonstrate significantly improved therapeutic performance, by regenerating skeletal muscles approaching native-like cell density with reduced fibrosis, and regenerating skin with hair follicle growth and increased dermis thickness. MSC proliferation within 1-week post-transplantation and differentiation at 3 - 4 weeks post-transplantation are suggested to contribute therapy augmentation. We expect this "bead-jet" printing system to strengthen the potential of MSC transplantation.

Vascularized Tumor Spheroid-on-a-Chip Model Verifies Synergistic Vasoprotective and Chemotherapeutic Effects.

Prolyl hydroxylases (PHD) inhibitors have been observed to improve drug distribution in mice tumors via blood vessel normalization, increasing the effectiveness of chemotherapy. These effects are yet to be demonstrated in human cell models. Tumor spheroids are three-dimensional cell clusters that have demonstrated great potential in drug evaluation for personalized medicine. Here, we used a perfusable vascularized tumor spheroid-on-a-chip to simulate the tumor microenvironment in vivo and demonstrated that the PHD inhibitor dimethylallyl glycine prevents the degradation of normal blood vessels while enhancing the efficacy of the anticancer drugs paclitaxel and cisplatin in human esophageal carcinoma (Eca-109) spheroids. Our results point to the potential of this model to evaluate anticancer drugs under more physiologically relevant conditions.

Injectable Mesenchymal Stem Cell-Laden Matrigel Microspheres for Endometrium Repair and Regeneration.

Endometrial injury and intrauterine adhesions are increasingly reported in recent years; however, treatment options remain limited. Intravenous injection of mesenchymal stem cells (MSCs) for endometrium regeneration has limited effectiveness as the retention rate of transplanted cells is low. Hydrogel-based tissue-engineered solutions, such as MSC-seeded bioscaffolds, are reported to increase retention rates; however, a less invasive alternative is still desirable. 560-µm homogeneous Matrigel microspheres are fabricated, loading them with about 1500 MSCs and injecting them into the injured endometria of rats' uteri. This minimally invasive procedure is proved to significantly increase endometrium thickness by over onefold after 21 d (p < 0.0001) and fertility rates from 25% to 75% in impaired and repaired uteri (p < 0.001), respectively. This study provides a minimally invasive alternative to endometrium repair with the promise to establish a broad-spectrum technique for MSC transplantation.

An Automated Organoid Platform with Inter-organoid Homogeneity and Inter-patient Heterogeneity.

Current organoid technologies require intensive manual manipulation and lack uniformity in organoid size and cell composition. We present here an automated organoid platform that generates uniform organoid precursors in high-throughput. This is achieved by templating from monodisperse Matrigel droplets and sequentially delivering them into wells using a synchronized microfluidic droplet printer. Each droplet encapsulates a certain number of cells (e.g., 1,500 cells), which statistically represent the heterogeneous cell population in a tumor section. The system produces >400-µm organoids within 1 week with both inter-organoid homogeneity and inter-patient heterogeneity. This enables automated organoid printing to obtain one organoid per well. The organoids recapitulate 97% gene mutations in the parental tumor and reflect the patient-to-patient variation in drug response and sensitivity, from which we obtained more than 80% accuracy among the 21 patients investigated. This organoid platform is anticipated to fulfill the personalized medicine goal of 1-week high-throughput screening for cancer patients.

Cascade Pumping Overcomes Hydraulic Resistance and Moderates Shear Conditions for Slow Gelatin Fiber Shaping in Narrow Tubes.

In microextrusion-based 3D bioprinting, shaping gel fibers online, i.e., in narrow tubes, benefits the structural maintenance after extrusion, but it is challenging for materials possessing slow sol-gel transition dynamics. Gelatin, for example, transforms into thermostable fibers via transglutaminase (TG) reaction in as much as 10 min. It causes dramatic flow resistance accumulation and shear stress increase in fluids moving along narrow tubes, resulting in channel clogging and cell detriments. In this study, we overcome the limitations by adopting cascade pumping and performing in a single peristaltic pump that comprises multi-channel pumping units. The pressure and shear stress reduction by over 1-fold are verified by finite element simulation; continuous gelatin fiber production and patterning in a substrate-free manner are achieved via slow online enzymatic cross-linking. The online fiber shaping can be scaled up by numbering up the pumping units and provides another paradigm for biomanufacturing.