An official website of the United States government
Electronic sensors based on biomaterials can lead to novel green technologies that are low cost, renewable, and eco-friendly. Here we demonstrate bioelectronic ammonia sensors made from protein nanowires harvested from the microorganism Geobacter sulfurreducens. The nanowire sensor responds to a broad range of ammonia concentrations (10 to 106 ppb), which covers the range relevant for industrial, environmental, and biomedical applications. The sensor also demonstrates high selectivity to ammonia compared to moisture and other common gases found in human breath. These results provide a proof-of-concept demonstration for developing protein nanowire based gas sensors for applications in industry, agriculture, environmental monitoring, and healthcare.
more »
« less
Microbial nanowires with genetically modified peptide ligands to sustainably fabricate electronic sensing devices
Nanowires have substantial potential as the sensor component in electronic sensing devices. However, surface functionalization of traditional nanowire and nanotube materials with short peptides that increase sensor selectivity and sensitivity requires complex chemistries with toxic reagents. In contrast, microorganisms can assemble pilin monomers into protein nanowires with intrinsic conductivity from renewable feedstocks, yielding an electronic material that is robust and stable in applications, but also biodegradable. Here we report that the sensitivity and selectivity of protein nanowire-based sensors can be modified with a simple plug and play genetic approach in which a short peptide sequence, designed to bind the analyte of interest, is incorporated into the pilin protein that is microbially assembled into nanowires. We employed a scalable Escherichia coli chassis to fabricate protein nanowires that displayed either a peptide previously demonstrated to effectively bind ammonia, or a peptide known to bind acetic acid. Sensors comprised of thin films of the nanowires amended with the ammonia-specific peptide had a ca. 100-fold greater response to ammonia than sensors made with unmodified protein nanowires. Protein nanowires with the peptide that binds acetic acid yielded a 4-fold higher response than nanowires without the peptide. The protein nanowire-based sensors had greater responses than previously reported sensors fabricated with other nanomaterials. The results demonstrate that protein nanowires with enhanced sensor response for analytes of interest can be fabricated with a flexible genetic strategy that sustainably eliminates the energy, environmental, and health concerns associated with other common nanomaterials.
more »
« less
- Award ID(s):
- 2027102
- PAR ID:
- 10477366
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Biosensors and Bioelectronics
- Volume:
- 226
- Issue:
- C
- ISSN:
- 0956-5663
- Page Range / eLocation ID:
- 115147
- Subject(s) / Keyword(s):
- Protein nanowire Sustainable electronics e-biologics Nanowire sensor Electromicrobiology
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Electrically conductive, genetically tunable, pilin-based protein nanowires (ePNs) expressed in Escherichia coli grown on the biodiesel byproduct glycerol are a sustainable electronic material. They were previously shown to effectively function as sensing components for volatile analytes when deployed as thin films in electronic devices. However, thin-film devices are not suitable for analyzing components dissolved in water. To evaluate the possibility of fabricating a water-stable ePN matrix, ePNs purified from cells were mixed with polyvinyl butyral (PVB) to produce a transparent, electrically conductive, water-stable composite. ePN/PVB composite conductivity was tuned by changing the concentration of ePNs in the composite or genetically tailoring ePNs for different conductivities. Devices with an ePN/PVB sensing component rapidly responded in a linear fashion to changes in concentrations of dissolved ammonia or acetate. Genetically modifying nanowires to display an analyte-binding peptide on the ePN outer surface that was specific for ammonia or acetate increased sensing sensitivity and specificity. Composites comprised of whole cells of E. coli expressing ePNs and PVB were also electrically conductive. They functioned as sensing components whose sensitivity could also be tuned with the expression of ePNs displaying specific analyte-binding peptides. This approach avoids the laborious and time-consuming purification of protein nanowires from cells. The simplicity of sustainably fabricating an electronic sensing component with ePN-expressing E. coli mixed with a polymer, coupled with the potential of exquisitely tuning sensing specificity with facile ‘plug and play’ nanowire design, demonstrates the possibility of simply and inexpensively producing sensing devices for detecting a broad range of analytes.more » « less
-
Abstract Sustainably produced biomaterials can greatly improve the biocompatibility of wearable sensor technologies while reducing the energy and environmental impacts of materials fabrication and disposal. An electronic sensor device in which the sensing element is a thin (≈2 µm) film of electrically conductive protein nanowires harvested from the microbeGeobacter sulfurreducensis developed. The sensor rapidly responds to changes in humidity with high selectivity and sensitivity. The sensor is integrated on a flexible substrate as a wearable device, enabling real‐time monitoring of physiological conditions such as respiration and skin hydration. Noncontact body tracking is demonstrated with an array of sensors that detect a humidity gradient at distance from the skin with high sensitivity. Humidity gradients induce directional charge transport in the protein nanowires films, enabling the production of a current signal without applying an external voltage bias for powerless sensing. These results demonstrate the considerable promise for developing protein nanowire‐based wearable sensor devices.more » « less
-
Diamond-based sensors have shown great potential in the past few years due to their unique physicochemical properties. We report on the development of high-performance nitrogen-doped ultrananocrystalline diamond (UNCD) nanowire-based methane (CH4) gas sensors, taking advantage of a large surface-to-volume ratio and a small active area offered by the 1D nanowire geometry. The morphologic surface and crystalline structures of UNCD are also characterized by using scanning electron microscopy (SEM) and Raman scattering, respectively. By using synthesized nanowire arrays combined with 4-pin electrical electrodes, prototypic highly sensitive CH4 gas sensors have been designed, fabricated and tested. Various parameters including the sensitivity, response and recovery times, and thermal effect on the performance of the gas sensor have also been investigated in order to quantitate the sensing ability. Enhanced by the small grain size and porosity of the nanowire structure, fabricated nanowire UNCD sensors demonstrated a high sensitivity to CH4 gas at room temperature down to 2 ppm, as well as fast response and recovery times which are almost 10 times faster than that of regular nanodiamond thin film based sensors.more » « less
-
null (Ed.)Gallium oxide (Ga 2 O 3 ) and its most stable modification, monoclinic β-Ga 2 O 3 , is emerging as a primary material for power electronic devices, gas sensors and optical devices due to a high breakdown voltage, large bandgap, and optical transparency combined with electrical conductivity. Growth of β-Ga 2 O 3 is challenging and most methods require very high temperatures. Nanowires of β-Ga 2 O 3 have been investigated extensively as they might be advantageous for devices such as nanowire field effect transistors, and gas sensors benefiting from a large surface to volume ratio, among others. Here, we report a synthesis approach using a sulfide precursor (Ga 2 S 3 ), which requires relatively low substrate temperatures and short growth times to produce high-quality single crystalline β-Ga 2 O 3 nanowires in high yields. Even though Au- or Ag-rich nanoparticles are invariably observed at the nanowire tips, they merely serve as nucleation seeds while the nanowire growth proceeds via supply and local oxidation of gallium at the substrate interface. Absorption and cathodoluminescence spectroscopy on individual nanowires confirms a wide bandgap of 4.63 eV and strong luminescence with a maximum ∼2.7 eV. Determining the growth process, morphology, composition and optoelectronic properties on the single nanowire level is key to further application of the β-Ga 2 O 3 nanowires in electronic devices.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1016/j.bios.2023.115147
