skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • Informing rational design of graphene oxide through surface chemistry manipulations: properties governing electrochemical and biological activities
Title: Informing rational design of graphene oxide through surface chemistry manipulations: properties governing electrochemical and biological activities
It is increasingly realized that rational design is critical to advance potential applications and proactively preclude adverse consequences of carbon nanomaterials (CNMs). Central to this approach is the establishment of parametric relationships that correlate material properties to both their functional performance and inherent hazard. This work aims to decouple the causative mechanisms of material structure and surface chemistry as it relates to the electrochemical and biological activities of graphene oxide (GO). The results are evaluated in the context of established relationships between surface chemistry and oxygen functionalized multi-walled carbon nanotubes (O-MWCNTs), a carbon allotrope. Systematic manipulation of GO surface chemistry is achieved through thermal annealing (under inert conditions, 200–900 °C). To further elucidate the contribution of several properties, chemical reduction was also used as an approach to differentially modify the surface chemistry. Physicochemical properties of GO and reduced GO (rGO) samples were comprehensively characterized using multiple techniques (AFM, TGA, XPS, ATR-FTIR, Raman, and DLS). The results indicate that surface chemistry is a viable design handle to control both activities. Rather than a single direct property ( i.e. , relative presence of carbonyl-containing moieties), it is a balance of multiple consequential properties, (extent of dispersion, defect density, and electrical conductivity) in combination with the relative presence of carbonyl moieties that synergistically contribute to electrochemical and biological activities. The identification of these governing physicochemical properties aims to inform the establishment of design parameters to guide the rational and safe design of CNMs.  more » « less
Award ID(s):
1709031
PAR ID:
10064681
Author(s) / Creator(s):
;
Date Published:
Journal Name:
Green Chemistry
Volume:
19
Issue:
12
ISSN:
1463-9262
Page Range / eLocation ID:
2826 to 2838
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; (, Organic & Biomolecular Chemistry)
    null (Ed.)
    Fluorescent small molecules are powerful tools for visualizing biological events, embodying an essential facet of chemical biology. Since the discovery of the first organic fluorophore, quinine, in 1845, both synthetic and theoretical efforts have endeavored to “modulate” fluorescent compounds. An advantage of synthetic dyes is the ability to employ modern organic chemistry strategies to tailor chemical structures and thereby rationally tune photophysical properties and functionality of the fluorophore. This review explores general factors affecting fluorophore excitation and emission spectra, molar absorption, Stokes shift, and quantum efficiency; and provides guidelines for chemist to create novel probes. Structure–property relationships concerning the substituents are discussed in detail with examples for several dye families. We also present a survey of functional probes based on PeT, FRET, and environmental or photo-sensitivity, focusing on representative recent work in each category. We believe that a full understanding of dyes with diverse chemical moieties enables the rational design of probes for the precise interrogation of biochemical and biological phenomena. 
    more » « less
  2. ; ; ; ; ; ; ; (, npj Flexible Electronics)
    Abstract Paper-based electrochemical sensors provide the opportunity for low-cost, portable and environmentally friendly single-use chemical analysis and there are various reports of surface-functionalized paper electrodes. Here we report a composite paper electrode that is fabricated through designed papermaking using cellulose, carbon fibers (CF), and graphene oxide (GO). The composite paper has well-controlled structure, stable, and repeatable properties, and offers the electrocatalytic activities for sensitive and selective chemical detection. We demonstrate that this CF/GO/cellulose composite paper can be reduced electrochemically using relatively mild conditions and this GO reduction confers electrocatalytic properties to the composite paper. Finally, we demonstrate that this composite paper offers sensing performance (sensitivity and selectivity) comparable to, or better than, paper-based sensors prepared by small-batch surface-modification (e.g., printing) methods. We envision this coupling of industrialized papermaking technologies with interfacial engineering and electrochemical reduction can provide a platform for single-use and portable chemical detection for a wide range of applications. 
    more » « less
  3. ; ; ; ; ; ; ; ; (, Environmental Science: Nano)
    null (Ed.)
    The toxicity of graphene oxide (GO) has been documented for multiple species. However, GO has variable surface chemistry, and it is currently unclear whether changes in oxygen content impact GO-organism interactions the same way across species. In this study, a modified Hummer's GO (ARGO) was systematically reduced by thermal annealing at 200, 500, or 800 °C and toxicity towards bacteria ( Escherichia coli ), alga ( Scenedesmus obliquus ), cyanobacteria ( Microcystis aeruginosa ), and invertebrates ( Daphnia magna ) was assessed by measuring the effective concentrations inducing 50% inhibition (EC 50 ). The EC 50 –carbon/oxygen ratio relationships show similar trends for bacteria and invertebrates, where toxicity increases as the material is reduced. Conversely, cyanobacterial inhibition decreases as GO is reduced. Further testing supports differences in cell-GO interactions between bacteria and cyanobacteria. Cyanobacteria showed a decrease in metabolic activity, evidenced by a 69% reduction in esterase activity after ARGO exposure but no oxidative stress, measured by 2′,7′-dichlorodihydrofluorescein diacetate (H 2 DCFDA) fluorescence and catalase activity. In contrast, ARGO induced a 55% increase in H 2 DCFDA fluorescence and 342% increase in catalase activity in bacteria. These changes in cell–material interactions propose different mechanisms of action, a physical mechanism occurring in cyanobacteria, and a chemical mechanism in bacteria. The differences in GO toxicity observed in different organisms emphasize the need to differentiate the safe-by-design guidelines made for GO in relation to the potential organisms exposed. 
    more » « less
  4. ; ; ; (, Applied Spectroscopy)
    Fundamental understanding of chemistry and physical properties at the nanoscale enables the rational design of interface-based systems. Surface interactions underlie numerous technologies ranging from catalysis to organic thin films to biological systems. Since surface environments are especially prone to heterogeneity, it becomes crucial to characterize these systems with spatial resolution sufficient to localize individual active sites or defects. Spectroscopy presents as a powerful means to understand these interactions, but typical light-based techniques lack sufficient spatial resolution. This review describes the growing number of applications for the nanoscale spectroscopic technique, tip-enhanced Raman spectroscopy (TERS), with a focus on developments in areas that involve measurements in new environmental conditions, such as liquid, electrochemical, and ultrahigh vacuum. The expansion into unique environments enables the ability to spectroscopically define chemistry at the spatial limit. Through the confinement and enhancement of light at the apex of a plasmonic scanning probe microscopy tip, TERS is able to yield vibrational fingerprint information of molecules and materials with nanoscale resolution, providing insight into highly localized chemical effects. 
    more » « less
  5. ; ; ; ; ; ; ; (, Advanced Materials Interfaces)
    Abstract Marine biofouling is a sticky global problem that hinders maritime industries. Various microscale surface structures inspired by marine biological species have been explored for their anti‐fouling properties. However, systematic studies of anti‐marine‐fouling performance on surface architectures with characteristic length‐scales spanning from below 100 nm to greater than 10 µm are generally lacking. Herein, a study on the rational design and fabrication of ZnO/Al2O3core–shell nanowire architectures with tunable geometries (length, spacing, and branching) and surface chemistry is presented. The ability of the nanowires to significantly delay or prevent marine biofouling is demonstrated. Compared to planar surfaces, hydrophilic nanowires can reduce fouling coverage by up to ≈60% after 20 days. The fouling reduction mechanism is mainly due to two geometric effects: reduced effective settlement area and mechanical cell penetration. Additionally, superhydrophobic nanowires can completely prevent marine biofouling for up to 22 days. The nanowire surfaces are transparent across the visible spectrum, making them applicable to windows and oceanographic sensors. Through the rational control of surface nano‐architectures, the coupled relationships between wettability, transparency, and anti‐biofouling performance are identified. It is envisioned that the insights gained from the work can be used to systematically design surfaces that reduce marine biofouling in various industrial settings. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email