Effects of different colors of film mulch on soil temperature and rice growth in a non-flooded condition.

BACKGROUND: Rice cultivation under film mulching with no flooding is widely used as an effective water-saving technology. Different colors of film mulch have different effects on the soil hydrothermal environment and crop growth because of their different optical properties. However, the effects of different colors of film mulch on soil temperature and rice physiological growth are not clearly understood. RESULTS: Field experiments were conducted in 2019 and 2020 to investigate the effects of different color mulches on soil temperature and rice growth in a non-flooded condition. Transparent film (TM), black film (BM), two-color film (BWM, silver on the front and black on the back), and no film (NM) in a non-flooded condition were designed. Soil temperature variation at different soil depths of 0-0.25 m and rice plant height, stem thickness, dry matter, yield and quality were monitored. The results showed that compared to no mulching, the mulching treatment effectively increased the average soil temperature during the whole rice growth stage with the soil temperature ranked TM > BM > BWM. Compared with NM, the BM and BWM treatments increased rice yield by 12.1-17.7% and 6.4-14.4% in 2019 and 2020, respectively. The BWM had 18.2% and 6.8% greater gel consistency than NM in 2019 and 2020, respectively. CONCLUSION: Transparent film should be applied with care because of the high soil temperature stress. Black film and two-color film (silver on the front and black on the back) could be better option for rice yield, increasing and quality improving in a non-flooded condition. © 2023 Society of Chemical Industry.

Proapoptotic effect of control-released basic fibroblast growth factor on skin wound healing in a diabetic mouse model.

The ability of basic fibroblast growth factor (bFGF) to improve wound healing is attenuated by its short half-life in free form. This study aimed to enhance skin wound healing in a diabetes mouse model while concomitantly decreasing scar formation using control-released bFGF together with acidic gelatin hydrogel microspheres (AGHMs). Bilateral full-thickness wounds (10 mm in diameter) were made on the backs of db/db mice. Forty-five mice were divided into three groups, and the base of the wound under the panniculus carnosus and the wound periphery were injected with phosphate-buffered saline (300 µL) containing (1) control-released bFGF (50 µg), (2) control-released bFGF (20 µg), or (3) AGHMs alone. The size of the wound area was recorded on each postoperative day (POD). Mice were sacrificed on postoperative day 4, 7, 10, 14, and 28, and skin wound specimens were obtained to assess the endothelium/angiogenesis index via cluster of differentiation 31 immunohistochemistry, the proliferation index via Ki-67 immunohistochemistry, and the myofibroblast and fibroblast apoptosis indices by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling and alpha-smooth muscle actin or vimentin staining, respectively. Epithelialization rates and indices of proliferation and myofibroblast/fibroblast apoptosis were higher in the bFGF groups than in the AGHM group, mainly within 2 weeks of injury. No dose-effect relationship was found for control-released bFGF, although the actions of 50 µg bFGF seemed to last longer than those of 20 µg bFGF. Therefore, control-released bFGF may accelerate diabetic skin wound healing and induce myofibroblast/fibroblast apoptosis, thereby reducing scar formation.

Individual earmuff during reconstruction of the auricle.

BACKGROUND: Auricular reconstruction represents one of the most demanding challenges in craniofacial surgery. But some of the complications may be stimulated by trauma or continuing pressures. Therefore, earmuff is important to the reconstructed ears as a protective guard. The widely used traditional earmuff was designed by Tanzer and Chaisson. We renovated a more comfortable and much safer individual earmuffs using a low-temperature thermoplastic splint. METHODS: The low-temperature thermoplastic splint was softened by hot water at 60°C to 70°C. Afterward, the low-temperature thermoplastic splint was stretched over an oval plaster mold. Then, it was fabricated, followed by trimming of the excess material, leaving a quarter-inch flange attached to the cup. Individualized adjustment of the earmuff was performed by immersing in hot water at 60°C to 70°C. When intenerated, it was placed around the reconstructed ear for 10 to 15 minutes until completion of shaping could be achieved. Finally, the earmuff was fixed with elastic band, which was based on the size of child's head circumference and could be adjusted for the patient's comfort. RESULTS: The individualized earmuff was applied in more than 400 patients after surgery of microtia reconstruction. Such individualized earmuffs are proved to provide sufficient protection, while leaving no major problems. CONCLUSIONS: The individual earmuff provides effective protection, secure fit, and comfort for the reconstructed ear.

Cryoprotectant enables structural control of porous scaffolds for exploration of cellular mechano-responsiveness in 3D.

Despite the wide applications, systematic mechanobiological investigation of 3D porous scaffolds has yet to be performed due to the lack of methodologies for decoupling the complex interplay between structural and mechanical properties. Here, we discover the regulatory effect of cryoprotectants on ice crystal growth and use this property to realize separate control of the scaffold pore size and stiffness. Fibroblasts and macrophages are sensitive to both structural and mechanical properties of the gelatin scaffolds, particularly to pore sizes. Interestingly, macrophages within smaller and softer pores exhibit pro-inflammatory phenotype, whereas anti-inflammatory phenotype is induced by larger and stiffer pores. The structure-regulated cellular mechano-responsiveness is attributed to the physical confinement caused by pores or osmotic pressure. Finally, in vivo stimulation of endogenous fibroblasts and macrophages by implanted scaffolds produce mechano-responses similar to the corresponding cells in vitro, indicating that the physical properties of scaffolds can be leveraged to modulate tissue regeneration.

Physical Properties of Implanted Porous Bioscaffolds Regulate Skin Repair: Focusing on Mechanical and Structural Features.

Porous bioscaffolds are applied to facilitate skin repair since the early 1990s, but a perfect regeneration outcome has yet to be achieved. Until now, most efforts have focused on modulating the chemical properties of bioscaffolds, while physical properties are traditionally overlooked. Recent advances in mechanobiology and mechanotherapy have highlighted the importance of biomaterials' physical properties in the regulation of cellular behaviors and regenerative processes. In skin repair, the mechanical and structural features of porous bioscaffolds are two major physical properties that determine therapeutic efficacy. Here, first an overview of natural skin repair with an emphasis on the major biophysically sensitive cell types involved in this multistage process is provided, followed by an introduction of the four roles of bioscaffolds as skin implants. Then, how the mechanical and structural features of bioscaffolds influence these four roles is discussed. The mechanical and structural features of porous bioscaffolds should be tailored to balance the acceleration of wound closure and functional improvements of the repaired skin. This study emphasizes that decoupling and precise control of the mechanical and structural features of bioscaffolds are significant aspects that should be considered in future biomaterial optimization, which can build a foundation to ultimately achieve perfect skin regeneration outcomes.

Preconditioning of mesenchymal stromal cells toward nucleus pulposus-like cells by microcryogels-based 3D cell culture and syringe-based pressure loading system.

To precondition mesenchymal stromal/stem cells (MSCs) with mechanical stimulation may enhance cell survival and functions following implantation in load bearing environment such as nucleus pulposus (NP) in intervertebral disc (IVD). In this study, preconditioning of MSCs toward NP-like cells was achieved in previously developed poly (ethylene glycol) diacrylate (PEGDA) microcryogels (PMs) within a syringe-based three-dimensional (3D) culture system which provided a facile and cost-effective pressure loading approach. PMs loaded with alginate and MSCs could be incubated in a sealable syringe which could be air-compressed to apply pressure loading through a programmable syringe pump. Expression levels of chondrogenic marker genes SOX9, COL II, and ACAN were significantly upregulated in MSCs when pressure loading of 0.2 MPa or 0.8 MPa was implemented. Expression levels of COL I and COL X were downregulated when pressure loading was applied. In a nude mouse model, MSCs loaded in PMs mechanically stimulated for three days were subcutaneously injected using the same culture syringe. Three weeks postinjection, more proteoglycans (PGs) were deposited and more SOX9 and COL II but less COL I and COL X were stained in 0.2 MPa group. Furthermore, injectable MSCs-loaded PMs were utilized in an ex vivo rabbit IVD organ culture model that demonstrated the leak-proof function and enhanced cell retention of PMs assisted cell delivery to a load bearing environment for potential NP regeneration. This microcryogels-based 3D cell culture and syringe-based pressure loading system represents a novel method for 3D cell culture with mechanical stimulation for better function. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 507-520, 2017.

Pathology-targeted cell delivery via injectable micro-scaffold capsule mediated by endogenous TGase.

Targeted cell delivery to lesion sites via minimally invasive approach remains an unmet need in regenerative medicine to endow satisfactory therapeutic efficacy and minimized side-effects. Here, we rationally designed a pathology-targeted cell delivery strategy leveraging injectable micro-scaffolds as cell-loading capsule and endogenous tissue transglutaminase (TGase) at lesion site as adhesive. Up-regulated TGase post-liver injury catalyzed chemical bonding between the glutamine and lysine residues on liver surface and micro-scaffolds both ex vivo and in vivo, facilitating sufficient adhesion on the pathological liver. Upon intraperitoneal injection, Mesenchymal Stem Cell-loaded capsules, exhibiting cell protection from shear-induced damage and post-transplantation anoikis, adhered to the CCl4-treated liver with a hundred-fold improvement in targeting efficiency (70.72%) compared to free-cell injection, which dramatically improved mice survival (33.3% vs. 0% for free-cell therapy) even with low-dosage treatment. This unique and widely-applicable cell delivery mechanism and strategy hold great promise for transforming cell therapy for refractory diseases.

Comparison of cell behavior on pva/pva-gelatin electrospun nanofibers with random and aligned configuration.

Electrospinning technique is able to create nanofibers with specific orientation. Poly(vinyl alcohol) (PVA) have good mechanical stability but poor cell adhesion property due to the low affinity of protein. In this paper, extracellular matrix, gelatin is incorporated into PVA solution to form electrospun PVA-gelatin nanofibers membrane. Both randomly oriented and aligned nanofibers are used to investigate the topography-induced behavior of fibroblasts. Surface morphology of the fibers is studied by optical microscopy and scanning electron microscopy (SEM) coupled with image analysis. Functional group composition in PVA or PVA-gelatin is investigated by Fourier Transform Infrared (FTIR). The morphological changes, surface coverage, viability and proliferation of fibroblasts influenced by PVA and PVA-gelatin nanofibers with randomly orientated or aligned configuration are systematically compared. Fibroblasts growing on PVA-gelatin fibers show significantly larger projected areas as compared with those cultivated on PVA fibers which p-value is smaller than 0.005. Cells on PVA-gelatin aligned fibers stretch out extensively and their intracellular stress fiber pull nucleus to deform. Results suggest that instead of the anisotropic topology within the scaffold trigger the preferential orientation of cells, the adhesion of cell membrane to gelatin have substantial influence on cellular behavior.

Substrate stiffness orchestrates epithelial cellular heterogeneity with controlled proliferative pattern via E-cadherin/ß-catenin mechanotransduction.

UNLABELLED: Epithelial cellular heterogeneity has been observed in pathological tissues with abnormal matrix stiffness and cells cultured on rigid substrates. However, it remains unclear how matrix stiffness influences cellular heterogeneity formation in multi-cellular population. Here, we demonstrated that cellular heterogeneity regulated by substrate stiffness is evident starting from the initial single-cell stage (indicated by cellular Young's modulus and morphology) until the resulting multi-cellular stage (indicated by cellular functions) through distinguished proliferative patterns. Epithelial cells on soft substrate proliferated in a neighbor-dependent manner with stronger E-cadherin expression and more homogeneous E-cadherin/ß-catenin localization compared to those on coverslips, which resulted in reduced heterogeneity in downstream cellular functions of the multi-cellular population. In particular, decreased heterogeneity in human embryonic stem cells upon expansion and endodermal induction was achieved on soft substrate. Overall, our work provides new insights on mechanotransduction during epithelial proliferation which regulates the formation of cellular heterogeneity and potentially provides a highly efficient approach to regulate stem cell fate by fine-tuning substrate stiffness. STATEMENT OF SIGNIFICANCE: This study demonstrates that cellular heterogeneity regulated by substrate stiffness is evident starting from the initial single-cell stage until the resulting multi-cellular stage through distinguished proliferative patterns. During this process, E-cadherin/ß-catenin mechanotransduction is found to play important role in substrate stiffness-regulated epithelial cellular heterogeneity formation. In particular, decreased heterogeneity in human embryonic stem cells upon expansion and endodermal induction is achieved on soft substrate. Hence, we believe that this work not only provides new insights on mechanotransduction of E-cadherin/ß-catenin which regulates the formation of cellular heterogeneity during proliferation, but also potentially provides a highly efficient approach to regulate stem cell fate by fine-tuning substrate stiffness.

Concentric Magnetic Structures for Magnetophoretic Bead Collection, Cell Trapping and Analysis of Cell Morphological Changes Caused by Local Magnetic Forces.

Concentric magnetic structures (ring and square) with domain wall (DW) pinning geometry are designed for biological manipulation. Magnetic beads collection was firstly demonstrated to analyse the local magnetic field generated by DWs and the effective regions to capture magnetic targets of size 1 µm. Primary mouse embryonic fibroblasts (MEFs) are magnetically labeled by internalizing poly (styrene sulfonic acid) stabilized magnetic nanoparticles (PSS-MNPs) and then are selectively trapped by head-to-tail DWs (HH DWs) or tail-to-tail DWs (TT DWs) to be arranged into linear shape or cross shape. The morphologies and the nuclear geometry of the cells growing on two kinds of concentric magnetic structures are shown to be distinctive. The intracellular magnetic forces generated by the local magnetic field of DWs are found to influence the behaviour of cells.

Biomaterials as carrier, barrier and reactor for cell-based regenerative medicine.

Cell therapy has achieved tremendous success in regenerative medicine in the past several decades. However, challenges such as cell loss, death and immune-rejection after transplantation still persist. Biomaterials have been designed as carriers to deliver cells to desirable region for local tissue regeneration; as barriers to protect transplanted cells from host immune attack; or as reactors to stimulate host cell recruitment, homing and differentiation. With the assistance of biomaterials, improvement in treatment efficiency has been demonstrated in numerous animal models of degenerative diseases compared with routine free cell-based therapy. Emerging clinical applications of biomaterial assisted cell therapies further highlight their great promise in regenerative therapy and even cure for complex diseases, which have been failed to realize by conventional therapeutic approaches.