Interspecific comparisons of C\u3csub\u3e3\u3c/sub\u3e turfgrass for tennis use: I. Wear tolerance and carrying capacity under actual match play

Previous studies in the evaluation of wear tolerance have been conducted using wear simulators. Research to investigate wear tolerance of C3 turfgrasses under actual playing conditions and their carrying capacity is limited. Three grass tennis courts (replicates) maintained as official size (single) courts were constructed. Eight species and cultivars were randomized within the three courts (blocks): (1) ‘Keeneland’ Kentucky bluegrass (KB, Poa pratensis L.), (2) ‘Rubix’ KB, (3) ‘Villa’ velvet bentgrass (VBG, Agrostis canina L.), (4) ‘Puritan’ colonial bentgrass (CL, Agrostis capillaris L.), (5) ‘007’ creeping bentgrass (CB, Agrostis stolonifera L.), (6) fine fescue (FF, Festuca spp.) mixture, (7) ‘Karma’ perennial ryegrass (PR, Lolium perenne L.), and (8) ‘Wicked’ PR. Injury at the baseline was measured by counting healthy grass on four dates in 2017 and 2019 using an intersect grid. Carrying capacity at the baseline was derived as hours of play to sustain 90, 80, 70, and 60% grass cover. After 6 wk of actual tennis play involving \u3e120 participating players in 2017 and 2019, KB and PR were superior to other C3 turfgrass for wear tolerance and carrying capacity. These two species exhibited four times the carrying capacity of FF species and nearly 60% more carrying capacity than bentgrass (BG) species. Species of BG afforded higher shoot density and better traction than KB and PR, with VBG exhibiting the best traction, and FF and PR exhibiting the poorest traction. In 2017, greater cell wall content increased wear tolerance and carrying capacity. Velvet bentgrass was as good as KB and PR in overall wear tolerance and carrying capacity under actual match play

Mineral-based nanoparticles for arthritis treatment

Aspects of the invention are directed to mineral-based nanoparticles comprising silicate nanoparticles that induce human mesenchymal stem cells (hMSCs) into a cartilage-lineage through the upregulation of cartilage-specific genes resulting in the transformation of the cell phenotype into that of a chondrocyte, i.e., a cartilage producing cell. The silicate nanoparticles are synthesized through a process where the precipitate of sodium silicate is mixed with one or more elements and compounds and milled into nanoparticles.U

3D-printed bioactive scaffolds from nanosilicates and PEOT/PBT for bone tissue engineering

Additive manufacturing (AM) has shown promise in designing 3D scaffold for regenerative medicine. However, many synthetic biomaterials used for AM are bioinert. Here, we report synthesis of bioactive nanocomposites from a poly(ethylene oxide terephthalate) (PEOT)/poly(butylene terephthalate) (PBT) (PEOT/PBT) copolymer and 2D nanosilicates for fabricating 3D scaffolds for bone tissue engineering. PEOT/PBT have been shown to support calcification and bone bonding ability in vivo, while 2D nanosilicates induce osteogenic differentiation of human mesenchymal stem cells (hMSCs) in absence of osteoinductive agents. The effect of nanosilicates addition to PEOT/PBT on structural, mechanical and biological properties is investigated. Specifically, the addition of nanosilicate to PEOT/ PBT improves the stability of nanocomposites in physiological conditions, as nanosilicate suppressed the degradation rate of copolymer. However, no significant increase in the mechanical stiffness of scaffold due to the addition of nanosilicates is observed. The addition of nanosilicates to PEOT/PBT improves the bioactive properties of AM nanocomposites as demonstrated in vitro. hMSCs readily proliferated on the scaffolds containing nanosilicates and resulted in significant upregulation of osteo-related proteins and production of mineralized matrix. The synergistic ability of nanosilicates and PEOT/PBT can be utilized for designing bioactive scaffolds for bone tissue engineering

Sequential Thiol–Ene and Tetrazine Click Reactions for the Polymerization and Functionalization of Hydrogel Microparticles

Click chemistry is a versatile tool for the synthesis and functionalization of polymeric biomaterials. Here, we describe a versatile new strategy for producing bioactive, protein-functionalized poly­(ethylene glycol) (PEG) hydrogel microparticles that is based on sequential thiol–ene and tetrazine click reactions. Briefly, tetra-functional PEG-norbornene macromer and dithiothreitol (SH) cross-linker were combined at a 0.75:1 [SH]:[norbornene] ratio, emulsified in a continuous Dextran phase, and then photopolymerized to form PEG hydrogel microparticles that varied from 8 to 30 μm in diameter, depending on the PEG concentration used. Subsequently, tetrazine-functionalized protein was conjugated to unreacted norbornene groups in the PEG microparticles. Tetrazine-mediated protein tethering to the microparticles was first demonstrated using fluorescein-labeled ovalbumin as a model protein. Subsequently, bioactive protein tethering was demonstrated using alkaline phosphatase (ALP) and glucose oxidase (GOx). Enzyme activity assays demonstrated that both ALP and GOx maintained their bioactivity and imparted tunable bioactivity to the microparticles that depended on the amount of enzyme added. ALP-functionalized microparticles were also observed to initiate calcium phosphate mineralization <i>in vitro</i> when incubated with calcium glycerophosphate. Collectively, these results show that protein-functionalized hydrogel microparticles with tunable bioactive properties can be easily synthesized using sequential click chemistry reactions. This approach has potential for future applications in tissue engineering, drug delivery, and biosensing

Mechanically Stiff Nanocomposite Hydrogels at Ultralow Nanoparticle Content

Although hydrogels are able to mimic native tissue microenvironments, their utility for biomedical applications is severely hampered due to limited mechanical stiffness and low toughness. Despite recent progress in designing stiff and tough hydrogels, it is still challenging to achieve a cell-friendly, high modulus construct. Here, we report a highly efficient method to reinforce collagen-based hydrogels using extremely low concentrations of a nanoparticulate-reinforcing agent that acts as a cross-link epicenter. Extraordinarily, the addition of these nanoparticles at a 10 000-fold lower concentration relative to polymer resulted in a more than 10-fold increase in mechanical stiffness and a 20-fold increase in toughness. We attribute the high stiffness of the nanocomposite network to the chemical functionality of the nanoparticles, which enabled the cross-linking of multiple polymeric chains to the nanoparticle surface. The mechanical stiffness of the nanoengineered hydrogel can be tailored between 0.2 and 200 kPa simply by manipulating the size of the nanoparticles (4, 8, and 12 nm), as well as the concentrations of the nanoparticles and polymer. Moreover, cells can be easily encapsulated within the nanoparticulate-reinforced hydrogel network, showing high viability. In addition, encapsulated cells were able to sense and respond to matrix stiffness. Overall, these results demonstrate a facile approach to modulate the mechanical stiffness of collagen-based hydrogels and may have broad utility for various biomedical applications, including use as tissue-engineered scaffolds and cell/protein delivery vehicles

Nanoengineered Ionic–Covalent Entanglement (NICE) Bioinks for 3D Bioprinting

We introduce an enhanced nanoengineered ionic-covalent entanglement (NICE) bioink for the fabrication of mechanically stiff and elastomeric 3D biostructures. NICE bioink formulations combine nanocomposite and ionic-covalent entanglement (ICE) strengthening mechanisms to print customizable cell-laden constructs for tissue engineering with high structural fidelity and mechanical stiffness. Nanocomposite and ICE strengthening mechanisms complement each other through synergistic interactions, improving mechanical strength, elasticity, toughness, and flow properties beyond the sum of the effects of either reinforcement technique alone. Herschel-Bulkley flow behavior shields encapsulated cells from excessive shear stresses during extrusion. The encapsulated cells readily proliferate and maintain high cell viability over 120 days within the 3D-printed structure, which is vital for long-term tissue regeneration. A unique aspect of the NICE bioink is its ability to print much taller structures, with higher aspect ratios, than can be achieved with conventional bioinks without requiring secondary supports. We envision that NICE bioinks can be used to bioprint complex, large-scale, cell-laden constructs for tissue engineering with high structural fidelity and mechanical stiffness for applications in custom bioprinted scaffolds and tissue engineered implants