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Amperometric urea biosensors based on sulfonated graphene/polyaniline nanocomposite.

Das G, Yoon HH - Int J Nanomedicine (2015)

Bottom Line: The biosensor achieved a broad linear range of detection (0.12-12.3 mM) with a notable response time of approximately 5 seconds.Moreover, the fabricated biosensor retained 81% of its initial activity (based on sensitivity) after 15 days of storage at 4°C.The ease of fabrication coupled with the low cost and good electrochemical performance of this system holds potential for the development of solid-state biosensors for urea detection.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical and Biological Engineering, Gachon University, Seongnam, Gyeonggi-do, South Korea.

ABSTRACT
An electrochemical biosensor based on sulfonated graphene/polyaniline nanocomposite was developed for urea analysis. Oxidative polymerization of aniline in the presence of sulfonated graphene oxide was carried out by electrochemical methods in an aqueous environment. The structural properties of the nanocomposite were characterized by Fourier-transform infrared, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques. The urease enzyme-immobilized sulfonated graphene/polyaniline nanocomposite film showed impressive performance in the electroanalytical detection of urea with a detection limit of 0.050 mM and a sensitivity of 0.85 (μA · cm(-2)·mM(-1). The biosensor achieved a broad linear range of detection (0.12-12.3 mM) with a notable response time of approximately 5 seconds. Moreover, the fabricated biosensor retained 81% of its initial activity (based on sensitivity) after 15 days of storage at 4°C. The ease of fabrication coupled with the low cost and good electrochemical performance of this system holds potential for the development of solid-state biosensors for urea detection.

No MeSH data available.


Raman spectra.Notes: (A) GO and SGO; and (B) SG-PANI. Inset: Shows the enlarged portion indicated in the red dotted circle.Abbreviations: GO, graphene oxide; SGO, sulfonated graphene oxide; SG-PANI, sulfonated graphene/polyaniline; ID, intensity of D band; IG, intensity of G band.
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f6-ijn-10-055: Raman spectra.Notes: (A) GO and SGO; and (B) SG-PANI. Inset: Shows the enlarged portion indicated in the red dotted circle.Abbreviations: GO, graphene oxide; SGO, sulfonated graphene oxide; SG-PANI, sulfonated graphene/polyaniline; ID, intensity of D band; IG, intensity of G band.

Mentions: The Raman spectra of GO, SGO, and SG-PANI are shown in Figure 6. The Raman spectra show two characteristic peaks centered approximately 1,351 and 1,594 cm−1, corresponding to the D band due to a breathing mode of κ-point photons of A1g symmetry, and to the G mode originated from the first-order scattering of E2g phonons by the sp2 carbon of GO, respectively.40 The ratio between the intensity of D band (ID) to G band (IG) increased from 0.92 for GO to 1.02 for SGO, which indicates a decrease in the sp2 carbon domain size. Compared to GO, in the case of the SGO, the positions of the D and G bands shifted to 1,345 cm−1 and 1,598 cm−1 (Figure 6A), respectively. The shift of the D and G bands in SG-PANI denotes lattice distortion of graphene in the presence of PANI.41 Several additional peaks were observed for SG-PANI (Figure 6B) such as the peak at 1,266 cm−1 due to the C–H bending vibration of the benzoid ring, at 1,174 cm−1 corresponding to the C–H bending of the quinoid ring, and the peaks at 1,041 and 1,000 cm−1 corresponding to C–H bending of the quinoid ring and to the C–N+ stretching of the bipolaron and polaron structure of PANI, respectively.41–43 The appearance of such peaks indicates the formation of an emeraldine salt-type structure of PANI on SG. The spectrum of the SG-PANI composite included bands corresponding to both individual components in good agreement with the FTIR results.


Amperometric urea biosensors based on sulfonated graphene/polyaniline nanocomposite.

Das G, Yoon HH - Int J Nanomedicine (2015)

Raman spectra.Notes: (A) GO and SGO; and (B) SG-PANI. Inset: Shows the enlarged portion indicated in the red dotted circle.Abbreviations: GO, graphene oxide; SGO, sulfonated graphene oxide; SG-PANI, sulfonated graphene/polyaniline; ID, intensity of D band; IG, intensity of G band.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4554425&req=5

f6-ijn-10-055: Raman spectra.Notes: (A) GO and SGO; and (B) SG-PANI. Inset: Shows the enlarged portion indicated in the red dotted circle.Abbreviations: GO, graphene oxide; SGO, sulfonated graphene oxide; SG-PANI, sulfonated graphene/polyaniline; ID, intensity of D band; IG, intensity of G band.
Mentions: The Raman spectra of GO, SGO, and SG-PANI are shown in Figure 6. The Raman spectra show two characteristic peaks centered approximately 1,351 and 1,594 cm−1, corresponding to the D band due to a breathing mode of κ-point photons of A1g symmetry, and to the G mode originated from the first-order scattering of E2g phonons by the sp2 carbon of GO, respectively.40 The ratio between the intensity of D band (ID) to G band (IG) increased from 0.92 for GO to 1.02 for SGO, which indicates a decrease in the sp2 carbon domain size. Compared to GO, in the case of the SGO, the positions of the D and G bands shifted to 1,345 cm−1 and 1,598 cm−1 (Figure 6A), respectively. The shift of the D and G bands in SG-PANI denotes lattice distortion of graphene in the presence of PANI.41 Several additional peaks were observed for SG-PANI (Figure 6B) such as the peak at 1,266 cm−1 due to the C–H bending vibration of the benzoid ring, at 1,174 cm−1 corresponding to the C–H bending of the quinoid ring, and the peaks at 1,041 and 1,000 cm−1 corresponding to C–H bending of the quinoid ring and to the C–N+ stretching of the bipolaron and polaron structure of PANI, respectively.41–43 The appearance of such peaks indicates the formation of an emeraldine salt-type structure of PANI on SG. The spectrum of the SG-PANI composite included bands corresponding to both individual components in good agreement with the FTIR results.

Bottom Line: The biosensor achieved a broad linear range of detection (0.12-12.3 mM) with a notable response time of approximately 5 seconds.Moreover, the fabricated biosensor retained 81% of its initial activity (based on sensitivity) after 15 days of storage at 4°C.The ease of fabrication coupled with the low cost and good electrochemical performance of this system holds potential for the development of solid-state biosensors for urea detection.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical and Biological Engineering, Gachon University, Seongnam, Gyeonggi-do, South Korea.

ABSTRACT
An electrochemical biosensor based on sulfonated graphene/polyaniline nanocomposite was developed for urea analysis. Oxidative polymerization of aniline in the presence of sulfonated graphene oxide was carried out by electrochemical methods in an aqueous environment. The structural properties of the nanocomposite were characterized by Fourier-transform infrared, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques. The urease enzyme-immobilized sulfonated graphene/polyaniline nanocomposite film showed impressive performance in the electroanalytical detection of urea with a detection limit of 0.050 mM and a sensitivity of 0.85 (μA · cm(-2)·mM(-1). The biosensor achieved a broad linear range of detection (0.12-12.3 mM) with a notable response time of approximately 5 seconds. Moreover, the fabricated biosensor retained 81% of its initial activity (based on sensitivity) after 15 days of storage at 4°C. The ease of fabrication coupled with the low cost and good electrochemical performance of this system holds potential for the development of solid-state biosensors for urea detection.

No MeSH data available.