2-Ketophenyl Assisted Biomimetic Synthesis of 3-Thio Substituted Glycals at Room Temperature

Herein we designed a strategy for the synthesis of regioselective and stereoselective displacement of C-3 acetate group in the presence of other C-4 and C-6 acetate of 2-ketophenyl-glycal by different aromatic and cyclic aliphatic thiol nucleophiles taking inspiration from cytosolic esterase mediated thiolation of glucosamine sugars into cellular glycan. Under a mild base condition at room temperature, the protocol generated a library of 3-arylthiosugars with excellent yields and high axial selectivity. This stereoselective approach tolerated well with different ester-protected glycals and thiophenols, aliphatic cyclic thiols, and mercaptans. A variety of control experiments were conducted to establish the mechanism and reason behind the stereoselectivity.     

A New Strong-Acid Free Route to Produce Xanthan Gum-PANI Composite Scaffold Supporting Bioelectricity

Conductive hybrid xanthan gum (XG)–polyaniline (PANI) biocomposites forming 3D structures able to mimic electrical biological functions are synthesized by a strong-acid free medium. In situ aniline oxidative chemical polymerizations are performed in XG water dispersions to produce stable XG–PANI pseudoplastic fluids. XG–PANI composites with 3D architectures are obtained by subsequent freeze-drying processes. The morphological investigation highlights the formation of porous structures; UV–vis and Raman spectroscopy characterizations assess the chemical structure of the produced composites. I–V measurements evidence electrical conductivity of the samples, while electrochemical analyses point out their capability to respond to electric stimuli with electron and ion exchanges in physiological-like environment. Trial tests on prostate cancer cells evaluate biocompatibility of the XG–PANI composite. Obtained results demonstrate that a strong acid-free route produces an electrically conductive and electrochemically active XG–PANI polymer composite. The investigation of charge transport and transfer, as well as of biocompatibility properties of composite materials produced in aqueous environments, brings new perspective for exploitation of such materials in biomedical applications. In particular, the developed strategy can be used to realize biomaterials working as scaffolds that require electrical stimulations for inducing cell growth and communication or for biosignals monitoring and analysis.     

Mimicking Non-Canonical Radical Cyclizations in the Synthesis of Dibenzocyclooctadiene Natural Products

Unique chemical structures that are often characteristic of biologically active natural products are often created by oxidative cyclizations. Many of these reactions are catalysed by ‘non-canonical’ or ‘thwarted’ iron oxygenases that appear to involve long-lived radicals. This perspective summarizes our group‘s efforts to mimic these biosynthetic transformations for the synthesis of highly oxidized dibenzocyclooctadiene lignan natural products using redox neutral photocatalysis. We describe the evolution of this research program, which hinges on the use of Okada's redox active ester, and show how multiple factors control the fate of the resulting radicals.     

Advances in 3D Bioprinting of Biomimetic and Engineered Meniscal Grafts

The meniscus plays a crucial role in loads distribution and protection of articular cartilage. Meniscal injury can result in cartilage degeneration, loss of mechanical stability in the knee joint and ultimately lead to arthritis. Surgical interventions provide only short-term pain relief but fail to repair or regenerate the injured meniscus. Emerging tissue engineering approaches based on 3D bioprinting provide alternatives to current surgical methods for meniscus repair. In this review, the current bioprinting techniques employed in developing engineered meniscus grafts are summarized and discuss the latest strategies for mimicking the gradient structure, composition, and viscoelastic properties of native meniscus. Recent progress is highlighted in gene-activated matrices for meniscus regeneration as well. Finally, a perspective is provided on the future development of 3D bioprinting for meniscus repair, emphasizing the potential of this technology to revolutionize meniscus regeneration and improve patient outcomes.     

Ionically Modified Gelatin Hydrogels Maintain Murine Myogenic Cell Viability and Fusion Capacity

For tissue engineering of skeletal muscles, there is a need for biomaterials which do not only allow cell attachment, proliferation, and differentiation, but also support the physiological conditions of the tissue. Next to the chemical nature and structure of the biomaterial, its response to the application of biophysical stimuli, such as mechanical deformation or application of electrical pulses, can impact in vitro tissue culture. In this study, gelatin methacryloyl (GelMA) is modified with hydrophilic 2-acryloxyethyltrimethylammonium chloride (AETA) and 3-sulfopropyl acrylate potassium (SPA) ionic comonomers to obtain a piezoionic hydrogel. Rheology, mass swelling, gel fraction, and mechanical characteristics are determined. The piezoionic properties of the SPA and AETA-modified GelMA are confirmed by a significant increase in ionic conductivity and an electrical response as a function of mechanical stress. Murine myoblasts display a viability of >95% after 1 week on the piezoionic hydrogels, confirming their biocompatibility. The GelMA modifications do not influence the fusion capacity of the seeded myoblasts or myotube width after myotube formation. These results describe a novel functionalization providing new possibilities to exploit piezo-effects in the tissue engineering field.     

Ballistic performance of novel design of bulletproof plates inspired by biomimetic approaches

Metal and polymer matrix composite materials are preferred in bulletproof applications due to their high-impact resistance and lightness. Personal/demand-specific designs that have become possible with the developing additive manufacturing technologies have brought a new perspective to armor technologies. At the same time, parts with complex structures designed with biomimetic approaches can be easily manufactured with additive manufacturing. In this study, biomimetic armors obtained from standard Carbon fiber reinforced polymer (CFRP) and Inconel 718 materials were compared with traditional armor structures. Within the scope of the study, 9 × 19 mm² parabellum and 7.62 mm NATO bullets were impacted at 275 m/s and 600 m/s speeds on biomimetic and conventional armor consisting of three and five layers. Bullet velocities during impact, deformation of bullets, deformation of armor, and harmonic behavior are discussed. The results obtained were also used to calculate the damped impact energies. In the study, it was determined that biomimetic plates could absorb 22%–38% more impact energy. It has been determined that CFRP materials can absorb 45% more impact energy compared to Inconel 718.     

Modulation of Biophysical Cues in Nature Inspired Patterning of Porous Silk Fibroin Scaffold for Replenishable Controlled Drug Delivery

While a sticking plasteris enough for healing of most of the minor cuts they may get routinely, critical situations like surgical, gunshot, accidental or diabetic wounds;lacarations and other cutaneous deep cuts may require implants and simultaneous medications for healing. From the biophysical standpoint, an internal force-based physical surface stimulusis crucial for cellular sensing during wound repair. In this paper, the authors report the fabrication of a porous, biomimmetically patterned silk fibroin scaffold loaded with ampicillin, which exhibits controlled release of the drug along with possible replenishment of the same. In vitro swelling study reveals that the scaffolds with hierarchical surface patterns exhibit lower swelling and degradation than other types of scaffolds. The scaffolds, that show remarkable broad–spectrum antibacterial efficacy, exhibit Korsemeyer–Peppas model for the ampicillin release patterns due to the structural hydrophobicity imparted by the patterns. Four distinct cell-matrix adhesion regimes are investigated for the fibroblasts to eventually form cell sheets all over the hierarchical surface structures. 4',6–diamidino–2–phenylindole (DAPI) and Fluorescein Diacetate (FDA) fluorescent staining clearly demonstrate the superiority of patterned surface over its other variants. A comparative immunofluorescence study among collagen I, vinculin, and vimentin expressions substantiated the patterned surface to be superior to others.     

Simple but Strong: A Mussel‐Inspired Hot Curing Adhesive Based on Polyvinyl Alcohol Backbone

The strong adhesion ability of mussel foot‐byssal proteins (Mfps) has inspired scientists to develop novel materials for strong and reversible adhesion, coating, antifouling, and many other applications. However, in many cases, the high costs and the tedious preparation steps of such bioinspired materials hamper the process to push them into practical application. Here a simple but effective way (one step) is presented to synthesize a mussel‐inspired glue from two cheap commercially available materials: polyvinyl alcohol (PVA) and 3,4‐dihydroxybenzaldehyde (DBA). This bioinspired hot curing adhesive exhibits a strong bonding ability as high as 17.3 MPa on stainless steel surfaces, which surpasses most of the commercially available adhesives.