Mussel-inspired, catechol-functionalized polypeptides were synthesized from natural feedstocks and investigated as redox-active organic electrode materials, to combine electrochemical performance with sustainability and cytocompatibility. Postpolymerization grafting of dopamine onto pre-established poly(α-l-glutamic acid)s resulted in low conjugation, giving poor aqueous solubility and failing to function electrochemically in initial solution-state studies. Therefore, a direct strategy was adopted, whereby the redox-active catechol functionality was embedded into the monomer, followed by ring-opening polymerization to afford a polypeptide bearing a catechol group at each repeat unit. In the solid state, WAXS revealed short-range order, thermogravimetric analysis (TGA) and microscale combustion calorimetry (MCC) indicated thermal stability and low flammability, and electrochemical evaluation demonstrated a quasi-reversible catechol/o-quinone aqueous redox process. The composite thin film electrochemical signal intensity was significantly greater for this poly(l-DOPA) than for the original catechol-grafted poly(α-l-glutamic acid). Cell-viability assays further support these catechol-functionalized polypeptides as viable components in sustainable and safe energy storage media.

Regenerative strategies for bone repair would benefit from scaffolds that are mechanically resilient and biologically compatible. We present a fully bioderived and 3D-printable composite scaffold that meets these requirements while offering environmental sustainability through the integration of CO2-derived eugenol polycarbonate, bioderived cross-linkers, and hydroxyapatite (HAp) reinforcement. This scaffold exhibits excellent thermal stability (T-g >= 60 degrees C and T-d >= 350 degrees C) and robust mechanical properties (flexural modulus similar to 2.54 GPa and compressive modulus similar to 220 MPa), aligning with the mechanical properties of human trabecular bone and outperforming reported polymer/HAp composites. It demonstrates exceptional creep resistance (similar to 0.82% strain under 3 MPa for 24 h), ensuring long-term mechanical integrity under physiological loads. A UV-assisted direct ink writing (DIW) technique, followed by post-UV curing, fabricates precise 3D structures that support cell attachment. The hydrophilicity of the scaffold is tunable via surface modifications to optimize cell-material interactions. In vitro cytocompatibility studies using MC3T3 preosteoblasts show >91% viability. Under simulated physiological conditions (PBS, 37 degrees C), the scaffold shows negligible mass loss over 18 weeks. Compared to conventional 3D-printed scaffolds that rely on petrochemical feedstocks and exhibit weaker mechanical resilience, this sustainable system offers a compelling combination of printability, mechanical robustness, and biocompatibility with potential for advanced bone regenerative therapies.

Inspired by Nature, we present a polypeptide-based organic redox-active material constructed from renewable feedstocks, L-glutamic acid (an amino acid) and riboflavin (vitamin B2), to address challenges with start-to-end-of-life management in energy storage systems (ESSs). The amino acid was utilized to establish a degradable polymer backbone, along which many copies of riboflavin were incorporated to serve as the redox-active pendant groups that enabled energy storage. The overall synthesis involved the ring-opening polymerization (ROP) of an l-glutamic acid-derived N-carboxyanhydride (NCA) monomer, followed by side chain activation with azides and, finally, click coupling to achieve installation of alkyne-functionalized riboflavin moieties. The steric bulkiness and rich chemical functionality of riboflavin resulted in synthetic complexities that required reaction optimization to achieve the desired polymer structure. Electrochemical characterization of the resultant riboflavin polypeptide, in organic electrolyte, showed quasireversible redox activity with a half-wave potential (E1/2) of ca. -1.10 V vs. ferrocene/ferrocenium (Fc/Fc+). Cell viability assays revealed biocompatibility, as indicated by negligible cytotoxicity for fibroblast cells. The polypeptide design, consisting of labile amide backbone linkages and side-chain ester functionalities that tethered the riboflavin units to the backbone, enabled hydrolytic degradation to recover building blocks for future upcycling or recycling. This bioinspired strategy advances the development of degradable redox-active polymers and promotes sustainable materials design for circular energy storage technologies.

We describe an update to an experiment demonstrating low-field NMR spectroscopy in the undergraduate physical chemistry laboratory. A Python-based data processing and analysis protocol is developed for this experiment. The Python language is used in fillable worksheets in the notebook software JupyterLab, providing an interactive means for students to work with the measured data step by step. The protocol teaches methods for the analysis of large data sets in science or engineering, a topic that is absent from traditional chemistry curricula. Python is among the most widely used modern tools for data analysis. In addition, its open-source nature reduces the barriers for adoption in an educational laboratory.

In this laboratory experiment, students modify a series of surfaces and explore the effects of varying surface chemistry and texture on wettability by different probe liquids. Students begin by building a simple contact angle goniometer utilizing their mobile phone cameras. Next, they contrast the wettability of planar glass substrates functionalized with alkyl silanes and fluorinated alkyl silanes and calculate surface free energies using Owens/Wendt plots. Subsequently, they synthesize ZnO tetrapods as robust textural elements and spray deposit the tetrapods onto stainless steel meshes to develop hierarchical texturation, which upon subsequent surface functionalization yields superhydrophobic and oleophobic surfaces. The series of experiments allow them to investigate the manner in which textured surfaces deviate from Young's equation and provide a vivid illustration of the thermodynamics of surface wettability. The laboratory exercise further provides a striking visual analogy for illustrating free energy landscapes and serves as a tangible means to demonstrate the role of surface chemistry with regards to the midstream oil-transportation infrastructure.

In only a few decades, lithium-ion batteries have revolutionized technologies, enabling the proliferation of portable devices and electric vehicles 1 , with substantial benefits for society. However, the rapid growth in technology has highlighted the ethical and environmental challenges of mining lithium, cobalt and other mineral ore resources, and the issues associated with the safe usage and non-hazardous disposal of batteries 2 . Only a small fraction of lithium-ion batteries are recycled, further exacerbating global material supply of strategic elements 3 – 5 . A potential alternative is to use organic-based redox-active materials 6 – 8 to develop rechargeable batteries that originate from ethically sourced, sustainable materials and enable on-demand deconstruction and reconstruction. Making such batteries is challenging because the active materials must be stable during operation but degradable at end of life. Further, the degradation products should be either environmentally benign or recyclable for reconstruction into a new battery. Here we demonstrate a metal-free, polypeptide-based battery, in which viologens and nitroxide radicals are incorporated as redox-active groups along polypeptide backbones to function as anode and cathode materials, respectively. These redox-active polypeptides perform as active materials that are stable during battery operation and subsequently degrade on demand in acidic conditions to generate amino acids, other building blocks and degradation products. Such a polypeptide-based battery is a first step to addressing the need for alternative chemistries for green and sustainable batteries in a future circular economy.

Rates of NO release from synthetic dinitrosyl iron complexes (DNICs) are shown to be responsive to coordination environments about iron. The effect of biologically relevant cellular components, glutathione and histidine, on the rate of NO release from a dimeric, "Roussin's Red Ester", DNIC with bridging μ-S thioglucose ligands, SGlucRRE or [(μ-SGluc)Fe(NO)2]2 (SGluc = 1-thio-β-d-glucose tetraacetate), was investigated. From the Griess assay and X-band EPR data, decomposition of the product from the histidine-cleaved dimer, [(SGluc)(NHis)Fe(NO)2], generated Fe(III) and increased the NO release rate in aqueous media when compared to the intact SGlucRRE precursor. In contrast, increasing concentrations of exogenous glutathione generated the stable [(SGluc)(GS)Fe(NO)2]- anion and depressed the rate of NO release. Both of the cleaved, monomeric intermediates were characterized with ESI-MS, EPR, and FT-IR spectroscopies. On the basis of the Griess assay coupled with data from an intracellular fluorometric probe, both the monomeric DNICs and dimeric SGlucRRE diffuse into smooth muscle cells, chosen as appropriate archetypes of vascular relaxation, and release their NO payload. Ultimately, this work provides insight into tuning NO release beyond the design of DNICs, through the incubation with safe, accessible biological molecules.

Understanding cellular remodeling in response to mechanical stimuli is a critical step in elucidating mechanical activation of biochemical signaling pathways. Experimental evidence indicates that external stress-induced subcellular adaptation is accomplished through dynamic cytoskeletal reorganization. To study the interactions between subcellular structures involved in transducing mechanical signals, we combined experimental data and computational simulations to evaluate real-time mechanical adaptation of the actin cytoskeletal network. Actin cytoskeleton was imaged at the same time as an external tensile force was applied to live vascular smooth muscle cells using a fibronectin-functionalized atomic force microscope probe. Moreover, we performed computational simulations of active cytoskeletal networks under an external tensile force. The experimental data and simulation results suggest that mechanical structural adaptation occurs before chemical adaptation during filament bundle formation: actin filaments first align in the direction of the external force by initializing anisotropic filament orientations, then the chemical evolution of the network follows the anisotropic structures to further develop the bundle-like geometry. Our findings present an alternative two-step explanation for the formation of actin bundles due to mechanical stimulation and provide new insights into the mechanism of mechanotransduction.

Understanding cellular remodeling in response to mechanical stimuli is a critical step in elucidating mechano-activation of biochemical signaling pathways. Experimental evidence indicates that external stress-induced subcellular adaptation is accomplished through dynamic cytoskeletal reorganization. To study the interactions between subcellular structures involved in transducing mechanical signals, we combined experimental and computational simulations to evaluate real-time mechanical adaptation of the actin cytoskeletal network. Actin cytoskeleton was imaged at the same time as an external tensile force was applied to live vascular smooth muscle cells using a fibronectin-functionalized atomic force microscope probe. In addition, we performed computational simulations of active cytoskeletal networks under a tensile external force. The experimental data and simulation results suggest that mechanical structural adaptation occurs before chemical adaptation during filament bundle formation: actin filaments first align in the direction of the external force, initializing anisotropic filament orientations, then the chemical evolution of the network follows the anisotropic structures to further develop the bundle-like geometry. This finding presents an alternative, novel explanation for the stress fiber formation and provides new insight into the mechanism of mechanotransduction. Author Summary Remodeling the cytoskeletal network in response to external force is key to mechanosensing and locomotion. Despite much focus on cytoskeletal remodeling in recent years, a comprehensive understanding of actin remodeling in real-time in cells under mechanical stimuli is still lacking. We integrated stress-induced 3D actin imaging and 3D computational simulations of actin cytoskeleton to study how the actin cytoskeleton form bundles and how these bundles evolve over time upon external tensile stress. We found a rapid actin alignment and a slower bundle evolution leading to denser bundles. Based on these results, we propose a “mechanics before chemistry” model of actin cytoskeleton remodeling under external force.

In this study, dinitrosyl iron complexes (DNICs) are shown to deliver nitric oxide (NO) into the cytosol of vascular smooth muscle cells (SMCs), which play a major role in vascular relaxation and contraction. Malfunction of SMCs can lead to hypertension, asthma, and erectile dysfunction, among other disorders. For comparison of the five DNIC derivatives, the following protocols were examined: (a) the Griess assay to detect nitrite (derived from NO conversion) in the absence and presence of SMCs; (b) the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay for cell viability; (c) an immunotoxicity assay to establish if DNICs stimulate immune response; and (d) a fluorometric assay to detect intracellular NO from treatment with DNICs. Dimeric Roussin's red ester (RRE)-type {Fe(NO)(2)}(9) complexes containing phenylthiolate bridges, [(mu-SPh)Fe(NO)(2)](2) or SPhRRE, were found to deliver NO with the lowest effect on cell toxicity (i.e., highest IC50). In contrast, the RRE-DNIC with the biocompatible thioglucose moiety, [(mu-SGlu)Fe(NO)(2)](2) (SGlu = 1-thio-beta-d-glucose tetraacetate) or SGluRRE, delivered a higher concentration of NO to the cytosol of SMCs with a 10-fold decrease in IC50. Additionally, monomeric DNICs stabilized by a bulky N-heterocyclic carbene (NHC), namely, 1,3-bis(2,4,6-trimethylphenyl)imidazolidene (IMes), were synthesized and yielded the DNIC complexes SGluNHC, [IMes(SGlu)Fe(NO)(2)], and SPhNHC, [IMes(SPh)Fe(NO)(2)]. These oxidized {Fe(NO)(2)}(9) NHC DNICs have an IC50 of similar to 7 mu M; however, the NHC-based complexes did not transfer NO into the SMC. Per contra, the reduced, mononuclear {Fe(NO)(2)}(10) neocuproine-based DNIC, neoDNIC, depressed the viability of the SMCs, as well as generated an increase of intracellular NO. Regardless of the coordination environment or oxidation state, all DNICs showed a dinitrosyl iron unit (DNIU)-dependent increase in viability. This study demonstrates a function relationship between the DNIU coordination environment and the efficacy of the DNIC treatments.

Magnolol, a neolignan natural product with antioxidant properties, contains inherent, orthogonal, phenolic, and alkenyl reactive groups that were used in both direct thermoset synthesis, as well as the stepwise synthesis of a small library of monomers, followed by transformation into thermoset materials. Each monomer from the small library was prepared via a single step functionalization reaction of the phenolic groups of magnolol. Thermoset materials were realized through solvent-free, thiol-ene reactions, and the resulting cross-linked materials were each comprised of thioether and ester linkages, with one retaining the hydrophilic phenols from magnolol, another having the phenols protected as an acetonide, and two others incorporating the phenols into additional cross-linking sites via hydrolytically labile carbonates or stable ether linkages. With this diversity of chemical compositions and structures, the thermosets displayed a range of thermomechanical properties including glass transition temperatures, Tg, 29-52 °C, onset of thermal degradation, Td, from about 290-360 °C, and ultimate strength up to 50 MPa. These tunable materials were studied in their degradation and biological properties with the aim of exploiting the antioxidant properties of the natural product. Hydrolytic degradation occurred under basic conditions (pH = 11) in all thermosets, but with kinetics that were dependent upon their chemical structures and mechanical properties: 20% mass loss was observed at 5, 7, 27, and 40 weeks for the thermosets produced from magnolol directly, acetonide-protected magnolol, bis(allyl carbonate)-functionalized magnolol, and bis(allyl ether)-functionalized magnolol, respectively. Isolated degradation products and model compounds displayed antioxidant properties similar to magnolol, as determined by both UV-vis and in vitro reactive oxygen species (ROS) assays. As these magnolol-based thermosets were found to also allow for extended cell culture, these materials may serve as promising degradable biomaterials.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The natural compound, isosorbide has been functionalized and rapidly cross-linked using thiol–ene click chemistry to afford an optically-transparent, flexible elastomer.

Honokiol, a highly functional phenolic- and alkenyl-containing neolignan natural product isolated fromMagnoliaplants, is an interesting bio-based resource which is shown to be useful as a monomer for the synthesis of poly(honokiol carbonate) (PHC).

Both monomeric and dimeric tetraacetylglucose-containing {Fe(NO)2}9 dinitrosyl iron complexes (DNICs) were prepared and examined for NO release in the presence of both chemical NO-trapping agents and endothelial cells.

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTPolymeric Nanostructures for Imaging and TherapyMahmoud Elsabahy*†‡§, Gyu Seong Heo†, Soon-Mi Lim†, Guorong Sun†, and Karen L. Wooley*†View Author Information† Department of Chemistry, Department of Chemical Engineering, Department of Materials Science & Engineering, Laboratory for Synthetic-Biologic Interactions, Texas A&M University, P.O. Box 30012, 3255 TAMU, College Station, Texas 77842-3012, United States‡ Department of Pharmaceutics, Faculty of Pharmacy, Assiut International Center of Nanomedicine, Al-Rajhy Liver Hospital, Assiut University, 71515 Assiut, Egypt§ Misr University for Science and Technology, Sixth of October City, Giza, Egypt*E-mail: [email protected]. Tel.: +2 088 2 2080711. Fax: +2 0882 2080774.*E-mail: [email protected]. Tel.: +1 979 845 4077. Fax: +1 979 862 1137.Cite this: Chem. Rev. 2015, 115, 19, 10967–11011Publication Date (Web):August 4, 2015Publication History Received4 March 2015Published online4 August 2015Published inissue 14 October 2015https://pubs.acs.org/doi/10.1021/acs.chemrev.5b00135https://doi.org/10.1021/acs.chemrev.5b00135review-articleACS PublicationsCopyright © 2015 American Chemical SocietyRequest reuse permissionsArticle Views11913Altmetric-Citations413LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Biological imaging,Cancer therapy,Nanoparticles,Pharmaceuticals,Polymers Get e-Alerts

The crosstalk between cells and their microenvironment enables cellular adaptation to external mechanical cues through the remodeling of cytoskeletal structures and cell-matrix adhesions to ensure normal cell function. This study investigates the relationship between the cytosketetal tension and integrin alpha(5)beta(1) adhesion strength to the matrix (i.e. fibronectin) in the context of RhoA-Src crosstalk. Integration of atomic force microscopy (AFM) with total internal reflection fluorescence and spinning-disk confocal microscopy enabled acquisition of complementary structural and functional measurements on live vascular smooth muscle cells expressing RhoA and c-Src variants (wild-type, dominant negative, constitutively active). Single ligand-receptor interaction measurements performed with AFM probes functionalized with fibronectin showed that RhoA and c-Src activation have different effects on cytoskeletat tension development, inducing two distinct force stiffness functional regimes for alpha(5)beta(1)-integrin binding to fibronectin. Moreover, fluorescence measurements showed that c-Src activation had a modest effect on actin morphology, while RhoA significantly modulated stress fiber formation. In addition, c-Src was associated with regulation of myosin light chain (MLC) phosphorylation, suggesting a c-Src-dependent modulation of RhoA pathway through activation of downstream effectors. Therefore, c-Src may be a possible component of cytoskeletal tension regulation through MLC activation. Our findings suggest that Src and RhoA coordinate a regulatory network that determines cytoskeletal tension through activation of actomyosin contractility. In turn, the cytoskeletal tension state modulates integrin alpha(5)beta(1)-fibronectin adhesion force.