Peng Zhao

Engineering native-mimetic tissue constructs is challenging due to their intricate biological and structural gradients. To address this, Hybprinter-SAM was developed by integrating three bioprinting technologies: syringe extrusion (SE), acoustic droplet ejection (ADE) and molten material extrusion (MME). This system not only enables the creation of mechanical gradients by integrating soft and rigid materials spanning 7 order magnitude of stiffness but also facilitates precise patterning and controlled localization of biochemical signals within printed scaffolds. This capability is beneficial in replicating the complexity of native tissues to enhance functionality. Both the printing process and biomaterials were optimized to balance printability, mechanical integrity, and biocompatibility. As a proof of concept, Hybprinter-SAM was used in a bone-tendon regeneration study to engineer a multi-material construct with patterned fibroblast growth factor 2 (FGF-2), resulting in markers indicative of fibrocartilage development. These findings highlight the potential of Hybprinter-SAM as a versatile platform for diverse tissue engineering applications that require complex, functionally graded tissue constructs.

Deposition of extracellular matrix (ECM) in the liver is an important feature of liver cirrhosis. Recovery from liver cirrhosis is physiologically challenging, partially due to the ECM in scar tissue showing resistance to cell‐mediated degradation by secreted matrix metalloproteinases (MMPs). Here, a cell‐mediated ECM‐degradation screening system (CEDSS) in vitro is constructed for high‐throughput searching for cells with tremendous degradation ability. ECM‐degrading liver sinusoidal endothelial cells (dLSECs) are screened using CEDSS, which exhibit 17 times the ability to degrade collagen when compared to other cells. The degradation ability of dLSECs is mediated by the upregulation of MMP9. In particular, mRNA expression of MMP9 shows an 833‐fold increase in dLSECs compared to normal endothelial cells (nLSECs), and MMP9 is regulated by transcription factor c‐Fos. In vivo, single intrasplenic injection of dLSECs alleviates advanced liver fibrosis in mice, while intraperitoneal administration of liver‐targeting peptide‐modified dLSECs shows enhanced fibrosis‐targeting effects. Degradative human umbilical vein endothelial cells (dHUVECs) prove their enhanced potential of clinical translation. Together, these results highlight the potential of ECM‐degrading endothelial cells in alleviating advanced liver fibrosis, thus providing remarkable insights in the development of ECM‐targeting therapeutics.

A water soluble and metal free phthalocyanine oligomer sulfonate (H2PPc⋅(SO3Na)x)(H2PPc⋅(SO3Na)x) has been synthesized and its corrosion inhibitive effect has been investigated by potentiodynamic measurement, ac impedance, and surface analysis. The potentiodynamic parameters show that H2PPc⋅(SO3Na)xH2PPc⋅(SO3Na)x can effectively reduce the corrosion current density and inhibit the corrosion of iron in 1molL−11molL−1 HCl at 313K313K . The H2PPc⋅(SO3Na)xH2PPc⋅(SO3Na)x functions as a mixed type inhibitor with anodic suppression outweighing the cathodic one. The ac impedance result, which is shown in the form of a compressed capacitive semicircle on complex plots, demonstrates that charge transfer resistance RctRct increases with the increase in concentration of H2PPc⋅(SO3Na)xH2PPc⋅(SO3Na)x in acidic solution. The X-ray photoelectron spectroscopy (XPS) result indicates the presence of the electronic donor-acceptor between Fe atoms and front molecular orbital of H2PPc⋅(SO3Na)xH2PPc⋅(SO3Na)x , evidence that the H2PPc⋅(SO3⋅Na)xH2PPc⋅(SO3⋅Na)x forms an adsorption layer on iron surface via chemical adsorption to protect iron from erosion in acid.