Macromolecular bioscience最新文献

In the field of orthopedic surgery, large bone defects resulting from trauma, surgical resection, or congenital anomalies present significant challenges. In many cases, treatment necessitates scaffold structures that not only support bone regeneration but also address potential bacterial infections that can impede healing. In this study, we developed 3D bioprinted scaffolds using hydrogel-based biomaterial ink comprising a blend of chitosan (CS) and agarose (AG), each separately fortified with ZnO, MgO, and CaO nanoparticles (NPs). We performed a comprehensive assessment of the inks' printability and wettability, and ascertained their rheological properties. The in vitro degradation of 3D bioprinted scaffolds was analyzed, their antibacterial capabilities against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were explored, and the differentiation of bone marrow mesenchymal stem cells (BMSCs) was evaluated. The findings indicated that the hydrogel, CS-AG (CA), composed of 3.5% (w/v) CS and 1.5% (w/v) AG, demonstrated superior printing characteristics. Among the nanoparticles, ZnO proved to be a notable booster of antibacterial activity and facilitated osteogenic differentiation and proliferation of bone marrow stem cells. Conversely, MgO showed similar antibacterial efficacy but was less successful in promoting cell proliferation compared to ZnO and CaO, whereas CaO displayed the weakest antibacterial efficacy. The results identify the ZnO NP-loaded CA biomaterial ink as a viable option for addressing bone abnormalities, enhancing bone repair, and preventing bacterial infection.

Bioprinting involves additive manufacturing of materials containing living cells, known as bioinks, which are formulated from cytocompatible hydrogel precursors. The bioink's characteristics before, during, and after crosslinking are critical for its printability, structural resolution, shape fidelity, and cell viability. The mechanical properties of printed constructs can be strongly influenced by their macroporous mesostructure, including pore size, filament diameter, and layer height, and are crucial for the intended applications in tissue engineering or regenerative medicine. It is known that the mechanical properties of hydrogels influence cell performance, but in turn, cells can also alter the mechanical properties of bioprinted constructs, which remain poorly understood. To explore these interdependencies, we selected an alginate-gelatin hydrogel (ALG-GEL), due to its well-known biocompatibility, combined with U87 cells and bioprinted three different multilayer macroporous mesostructures with varying porosity and filament diameter. We investigate how different macroporous mesostructures affect cells, how cells, in turn, influence mechanical properties, and whether the stability and mechanical properties of bioprinted macroporous mesostructures change over time. Our findings show that the bioprinted constructs are stable over the course of 14 days and highlight that cells can significantly influence their mechanical properties. This has important implications for biofabrication and tissue engineering applications.

Front Cover: In article 2500230, Amir Mellati, Somayeh Shahani, and co-workers present a collagen hydrogel reinforced with chitosan/poly(vinyl alcohol) nanofibers via wet electrospinning. The nanocomposite exhibits enhanced mechanical strength, reduced degradation, and improved cellular compatibility, retaining a nanofibrous microstructure that mimics the extracellular matrix, ideal for soft tissue engineering applications like cartilage and skin regeneration.

Macromol. Biosci. 2020, 20, 1900328

https://doi.org/10.1002/mabi.201900328

We have learned that the wrong image was used for Figure 10b, MT staining of the HA-SF group. Please kindly note that our discussion and conclusion were made based on the quantification data provided in Figure 10D, which was based on the CD68 staining data. These images were solely used as representatives of the stained tissues. Therefore, none of our discussion nor the conclusion part was influenced.

Correct image

We also have learned that there were a few typos in the caption of Figure 7. The correct captions should be as follows:

The cell results. a) SEM images of culture cells for 3 days (scale bar = 50 µm). b) Live and dead staining of cultured HaCat cells on nanofibers containing different amounts of ZO for 3 days. c) Fluorescent immunostaining of cells adhering to the mat surfaces after 3 days of culturing (yellow arrows showing the filopodial structures). d) Indirect MTT assay of different mats over 7 days of culturing (^*p < 0.05 and ^**p < 0.01).

Also in Materials and Methods, the SEM device should be revised to the following:

Morphologies and microstructures of all electrospun mats were analyzed using SEM (FESEM, MIRA3 TESCAN).

We apologize for these errors.

Timely and accurate assessment of wounds during the healing process is crucial for proper diagnosis and treatment. Conventional wound dressings lack both real-time monitoring capabilities and active therapeutic functionalities, limiting their effectiveness in dynamic wound environments. Herein, we report our proof-of-concept approach exploring the unique emission properties and antimicrobial activities of carbon nanodots (CNDs) for simultaneous detection and treatment of bacteria. This approach centers on the fabrication of well-defined CND-embedded poly(vinyl alcohol) (PVA) e-spun nanofibrous mats, which are crosslinked with degradable boronic ester (BE) crosslinks. The BE-CND/PVA mats exhibit stimuli-responsive degradation to pHs and hydrogen peroxide as well as pH-responsive release of CNDs. Promisingly, the mats turn out to be hemocompatible with blood and biocompatible with skin cells. Furthermore, they exhibit notable antimicrobial activity against Gram-negative bacteria and demonstrate great potential for real-time monitoring of wound pH to assess the wound status. These results suggest that BE-CND/PVA mats could significantly enhance wound healing by providing localized therapeutic action, reducing the risk of bacterial infections, and enabling non-invasive monitoring of wound progress.

Conventional gelatin's gel-to-sol transition upon heating restricts its utility in biomedical applications that benefit from a gel state at physiological temperatures such as Pluronic F127 and poly(NIPAAm). Herein, we present “rev-Gelatin”, a gelatin engineered with reverse thermo-responsive properties that undergoes a sol-to-gel transition as temperature rises from ambient to body temperature. Inspired by the phase dynamics of common materials like candy and ice cubes, whose surfaces soften or partially melt under warming, facilitating inter-object adhesion- rev-Gelatin leverages this concept to achieve fluidity at room temperature for easy injectability. At ambient temperature, rev-Gelatin exists as a microgel solution with sufficient fluidity in the sol state. However, upon exposure to elevated temperatures approaching physiological temperature, rev-Gelatin microgels coalesce through surface melting, forming a stable gel. This sol-to-gel transition is especially advantageous for hemostatic applications. Upon contact with blood, the temperature elevation induces rapid gelation of rev-Gelatin, effectively creating a barrier that reduces bleeding time and blood loss. Additionally, rev-Gelatin shows promise as a submucosal injection agent for gastrointestinal surgeries, making it a new class of thermo-sensitive biomaterials.