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Application of paper-supported printed gold electrodes for impedimetric immunosensor development.

Ihalainen P, Majumdar H, Viitala T, Törngren B, Närjeoja T, Määttänen A, Sarfraz J, Härmä H, Yliperttula M, Österbacka R, Peltonen J - Biosensors (Basel) (2012)

Bottom Line: In this article, we report on the formation and mode-of-operation of an affinity biosensor, where alternate layers of biotin/streptavidin/biotinylated-CRP-antigen/anti-CRP antibody are grown on printed gold electrodes on disposable paper-substrates.We have successfully demonstrated and detected the formation of consecutive layers of supra-molecular protein assembly using an electrical (impedimetric) technique.The article provides a possible biosensor development scheme, where-(1) fabrication of paper substrate (2) synthesis of gold nanoparticle inks (3) inkjet printing of gold electrodes on paper (4) formation of the biorecognition layers on the gold electrodes and (5) electrical (impedimetric) analysis of growth-all are coupled together to form a test-structure for a recyclable and inexpensive point-of-care diagnostic platform.

View Article: PubMed Central - PubMed

Affiliation: Center of Excellence for Functional Materials and Laboratory of Physical Chemistry, Department of Natural Sciences, Åbo Akademi University, Turku, Finland; E-Mails: bjorn.torngren@abo.fi (B.T.); anni.maattanen@abo.fi (A.M.); jawad.sarfraz@abo.fi (J.S.); jouko.peltonen@abo.fi (J.P.).

ABSTRACT
In this article, we report on the formation and mode-of-operation of an affinity biosensor, where alternate layers of biotin/streptavidin/biotinylated-CRP-antigen/anti-CRP antibody are grown on printed gold electrodes on disposable paper-substrates. We have successfully demonstrated and detected the formation of consecutive layers of supra-molecular protein assembly using an electrical (impedimetric) technique. The formation process is also supplemented and verified using conventional surface plasmon resonance (SPR) measurements and surface sensitive characterization techniques, such as X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The article provides a possible biosensor development scheme, where-(1) fabrication of paper substrate (2) synthesis of gold nanoparticle inks (3) inkjet printing of gold electrodes on paper (4) formation of the biorecognition layers on the gold electrodes and (5) electrical (impedimetric) analysis of growth-all are coupled together to form a test-structure for a recyclable and inexpensive point-of-care diagnostic platform.

No MeSH data available.


Capacitance as a function of frequency after application of SAM.
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biosensors-03-00001-f006: Capacitance as a function of frequency after application of SAM.

Mentions: The proximity of the aqueous solution to the metal electrode usually indicates a higher capacitance value due to the high polarity of the buffer solution. However, there is a large variation between the capacitive responses of the different batches of paper-supported printed gold electrodes (Figure 6). These electrodes were fabricated using dodecanethiol-capped AuNP ink, and it has been previously shown that after IR sintering, there is a residual thiol layer still present on the surface of the electrodes [19]. The amount varies between the different batches of electrodes. This residual thiol layer is the source for a lower capacitance observed for pristine gold electrodes, as discussed earlier in this work, as well as in previously published work [20]. From Figure 6, we see that there is a dispersion in the capacitance value (increasing capacitance with decreasing frequencies) in the low-frequency region. This can be attributed to the roughness of the electrodes. An interesting observation was made as a consequence of the thiolation of the gold electrodes with MBP thiols. Following thiolation, the gold electrodes were covered by a “dielectric” layer and the capacitance of the structure changed. The quality of the thiol layers governs the change in the capacitance of the device structure. It was observed that all the electrodes, previously exhibiting variations due to a varying amount of residual thiols on the surface, now exhibit perfect dielectric properties with no or very little variation after formation of the thiol-coverage. Moreover, the saturated capacitance values of the thiol-covered electrodes in most cases showed steady capacitance values (~200–230 nF) at lower frequencies, indicating a very good quality of the MBP thiol SAM.


Application of paper-supported printed gold electrodes for impedimetric immunosensor development.

Ihalainen P, Majumdar H, Viitala T, Törngren B, Närjeoja T, Määttänen A, Sarfraz J, Härmä H, Yliperttula M, Österbacka R, Peltonen J - Biosensors (Basel) (2012)

Capacitance as a function of frequency after application of SAM.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263588&req=5

biosensors-03-00001-f006: Capacitance as a function of frequency after application of SAM.
Mentions: The proximity of the aqueous solution to the metal electrode usually indicates a higher capacitance value due to the high polarity of the buffer solution. However, there is a large variation between the capacitive responses of the different batches of paper-supported printed gold electrodes (Figure 6). These electrodes were fabricated using dodecanethiol-capped AuNP ink, and it has been previously shown that after IR sintering, there is a residual thiol layer still present on the surface of the electrodes [19]. The amount varies between the different batches of electrodes. This residual thiol layer is the source for a lower capacitance observed for pristine gold electrodes, as discussed earlier in this work, as well as in previously published work [20]. From Figure 6, we see that there is a dispersion in the capacitance value (increasing capacitance with decreasing frequencies) in the low-frequency region. This can be attributed to the roughness of the electrodes. An interesting observation was made as a consequence of the thiolation of the gold electrodes with MBP thiols. Following thiolation, the gold electrodes were covered by a “dielectric” layer and the capacitance of the structure changed. The quality of the thiol layers governs the change in the capacitance of the device structure. It was observed that all the electrodes, previously exhibiting variations due to a varying amount of residual thiols on the surface, now exhibit perfect dielectric properties with no or very little variation after formation of the thiol-coverage. Moreover, the saturated capacitance values of the thiol-covered electrodes in most cases showed steady capacitance values (~200–230 nF) at lower frequencies, indicating a very good quality of the MBP thiol SAM.

Bottom Line: In this article, we report on the formation and mode-of-operation of an affinity biosensor, where alternate layers of biotin/streptavidin/biotinylated-CRP-antigen/anti-CRP antibody are grown on printed gold electrodes on disposable paper-substrates.We have successfully demonstrated and detected the formation of consecutive layers of supra-molecular protein assembly using an electrical (impedimetric) technique.The article provides a possible biosensor development scheme, where-(1) fabrication of paper substrate (2) synthesis of gold nanoparticle inks (3) inkjet printing of gold electrodes on paper (4) formation of the biorecognition layers on the gold electrodes and (5) electrical (impedimetric) analysis of growth-all are coupled together to form a test-structure for a recyclable and inexpensive point-of-care diagnostic platform.

View Article: PubMed Central - PubMed

Affiliation: Center of Excellence for Functional Materials and Laboratory of Physical Chemistry, Department of Natural Sciences, Åbo Akademi University, Turku, Finland; E-Mails: bjorn.torngren@abo.fi (B.T.); anni.maattanen@abo.fi (A.M.); jawad.sarfraz@abo.fi (J.S.); jouko.peltonen@abo.fi (J.P.).

ABSTRACT
In this article, we report on the formation and mode-of-operation of an affinity biosensor, where alternate layers of biotin/streptavidin/biotinylated-CRP-antigen/anti-CRP antibody are grown on printed gold electrodes on disposable paper-substrates. We have successfully demonstrated and detected the formation of consecutive layers of supra-molecular protein assembly using an electrical (impedimetric) technique. The formation process is also supplemented and verified using conventional surface plasmon resonance (SPR) measurements and surface sensitive characterization techniques, such as X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The article provides a possible biosensor development scheme, where-(1) fabrication of paper substrate (2) synthesis of gold nanoparticle inks (3) inkjet printing of gold electrodes on paper (4) formation of the biorecognition layers on the gold electrodes and (5) electrical (impedimetric) analysis of growth-all are coupled together to form a test-structure for a recyclable and inexpensive point-of-care diagnostic platform.

No MeSH data available.