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Detection of cardiac biomarkers using single polyaniline nanowire-based conductometric biosensors.

Lee I, Luo X, Huang J, Cui XT, Yun M - Biosensors (Basel) (2012)

Bottom Line: The single PANI nanowire-based biosensors displayed linear sensing profiles for concentrations ranging from hundreds (fg/mL) to tens (ng/mL).This single PANI nanowire-based biosensor demonstrated superior biosensing reliability with the feasibility of label free detection and improved processing cost efficiency due to good biocompatibility of PANI to monoclonal antibodies (mAbs).Therefore, this development of single PANI nanowire-based biosensors can be applied to other biosensors for cancer or other diseases.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA. inl8@pitt.edu.

ABSTRACT
The detection of myoglobin (Myo), cardiac troponin I (cTnI), creatine kinase-MB (CK-MB), and b-type natriuretic peptide (BNP) plays a vital role in diagnosing cardiovascular diseases. Here we present single site-specific polyaniline (PANI) nanowire biosensors that can detect cardiac biomarkers such as Myo, cTnI, CK-MB, and BNP with ultra-high sensitivity and good specificity. Using single PANI nanowire-based biosensors integrated with microfluidic channels, very low concentrations of Myo (100 pg/mL), cTnI (250 fg/mL), CK-MB (150 fg/mL), and BNP (50 fg/mL) were detected. The single PANI nanowire-based biosensors displayed linear sensing profiles for concentrations ranging from hundreds (fg/mL) to tens (ng/mL). In addition, devices showed a fast (few minutes) response satisfying respective reference conditions for Myo, cTnI, CK-MB, and BNP diagnosis of heart failure and for determining the stage of the disease. This single PANI nanowire-based biosensor demonstrated superior biosensing reliability with the feasibility of label free detection and improved processing cost efficiency due to good biocompatibility of PANI to monoclonal antibodies (mAbs). Therefore, this development of single PANI nanowire-based biosensors can be applied to other biosensors for cancer or other diseases.

No MeSH data available.


Related in: MedlinePlus

Tests of net surface charge effect on the functionalized PANI nanowires. (a) Decrease of conductance on the nanowire biosensor in sensing test with positively charged cTnI protein solutions (a: PBS of pH 5, b: 1 ng/mL, and c: 10 ng/mL). cTnI protein solutions were prepared with PBS of pH 5; (b) Comparison of sensitivity with different concentrations of cTnI detection. The nanowire biosensor shows significantly higher sensitivity with higher concentration. The mark “a” on black solid line presents the injection of BSA (100 ng/mL). After the injection of BSA, 300 fg/mL cTnI was injected into the biosensor.
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biosensors-02-00205-f006: Tests of net surface charge effect on the functionalized PANI nanowires. (a) Decrease of conductance on the nanowire biosensor in sensing test with positively charged cTnI protein solutions (a: PBS of pH 5, b: 1 ng/mL, and c: 10 ng/mL). cTnI protein solutions were prepared with PBS of pH 5; (b) Comparison of sensitivity with different concentrations of cTnI detection. The nanowire biosensor shows significantly higher sensitivity with higher concentration. The mark “a” on black solid line presents the injection of BSA (100 ng/mL). After the injection of BSA, 300 fg/mL cTnI was injected into the biosensor.

Mentions: The charge of the target protein solutions is related to the pH value of PBS, which is used as a buffer solution for the target protein, and the isoelectric point (pI) values of the proteins. It is generally known that Myo, cTnI, CK-MB, and BNP have pIs of 7.2, 5.2–5.4, 5.2, and 6.5 respectively [52,53,54]. The net charges of these target protein solutions in PBS (pH 7.4) are negative due to the pI values lower than pH 7.4. Based on our biosensing experiments and pI values of target proteins, it is assumed that the negative charges of target proteins resulted in a carrier accumulation on the PANI nanowire and consequently an increase of conductance. To verify this hypothesis, another cTnI solution in PBS of pH 5 was prepared and tested as shown in Figure 6(a). cTnI in PBS with pH 5 has positive charges due to a pI value of 5.2–5.4 and the binding to immobilized cTnI mAbs leads to carrier depletion in the PANI nanowire. Figure 6(a) shows that the conductance of the PANI nanowire decreased upon the addition of the cTnI solution. The inset of Figure 6(a) depicts the change of conductive area in the nanowire by depletion after binding the positive charged target protein to the mAbs.


Detection of cardiac biomarkers using single polyaniline nanowire-based conductometric biosensors.

Lee I, Luo X, Huang J, Cui XT, Yun M - Biosensors (Basel) (2012)

Tests of net surface charge effect on the functionalized PANI nanowires. (a) Decrease of conductance on the nanowire biosensor in sensing test with positively charged cTnI protein solutions (a: PBS of pH 5, b: 1 ng/mL, and c: 10 ng/mL). cTnI protein solutions were prepared with PBS of pH 5; (b) Comparison of sensitivity with different concentrations of cTnI detection. The nanowire biosensor shows significantly higher sensitivity with higher concentration. The mark “a” on black solid line presents the injection of BSA (100 ng/mL). After the injection of BSA, 300 fg/mL cTnI was injected into the biosensor.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4263570&req=5

biosensors-02-00205-f006: Tests of net surface charge effect on the functionalized PANI nanowires. (a) Decrease of conductance on the nanowire biosensor in sensing test with positively charged cTnI protein solutions (a: PBS of pH 5, b: 1 ng/mL, and c: 10 ng/mL). cTnI protein solutions were prepared with PBS of pH 5; (b) Comparison of sensitivity with different concentrations of cTnI detection. The nanowire biosensor shows significantly higher sensitivity with higher concentration. The mark “a” on black solid line presents the injection of BSA (100 ng/mL). After the injection of BSA, 300 fg/mL cTnI was injected into the biosensor.
Mentions: The charge of the target protein solutions is related to the pH value of PBS, which is used as a buffer solution for the target protein, and the isoelectric point (pI) values of the proteins. It is generally known that Myo, cTnI, CK-MB, and BNP have pIs of 7.2, 5.2–5.4, 5.2, and 6.5 respectively [52,53,54]. The net charges of these target protein solutions in PBS (pH 7.4) are negative due to the pI values lower than pH 7.4. Based on our biosensing experiments and pI values of target proteins, it is assumed that the negative charges of target proteins resulted in a carrier accumulation on the PANI nanowire and consequently an increase of conductance. To verify this hypothesis, another cTnI solution in PBS of pH 5 was prepared and tested as shown in Figure 6(a). cTnI in PBS with pH 5 has positive charges due to a pI value of 5.2–5.4 and the binding to immobilized cTnI mAbs leads to carrier depletion in the PANI nanowire. Figure 6(a) shows that the conductance of the PANI nanowire decreased upon the addition of the cTnI solution. The inset of Figure 6(a) depicts the change of conductive area in the nanowire by depletion after binding the positive charged target protein to the mAbs.

Bottom Line: The single PANI nanowire-based biosensors displayed linear sensing profiles for concentrations ranging from hundreds (fg/mL) to tens (ng/mL).This single PANI nanowire-based biosensor demonstrated superior biosensing reliability with the feasibility of label free detection and improved processing cost efficiency due to good biocompatibility of PANI to monoclonal antibodies (mAbs).Therefore, this development of single PANI nanowire-based biosensors can be applied to other biosensors for cancer or other diseases.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA. inl8@pitt.edu.

ABSTRACT
The detection of myoglobin (Myo), cardiac troponin I (cTnI), creatine kinase-MB (CK-MB), and b-type natriuretic peptide (BNP) plays a vital role in diagnosing cardiovascular diseases. Here we present single site-specific polyaniline (PANI) nanowire biosensors that can detect cardiac biomarkers such as Myo, cTnI, CK-MB, and BNP with ultra-high sensitivity and good specificity. Using single PANI nanowire-based biosensors integrated with microfluidic channels, very low concentrations of Myo (100 pg/mL), cTnI (250 fg/mL), CK-MB (150 fg/mL), and BNP (50 fg/mL) were detected. The single PANI nanowire-based biosensors displayed linear sensing profiles for concentrations ranging from hundreds (fg/mL) to tens (ng/mL). In addition, devices showed a fast (few minutes) response satisfying respective reference conditions for Myo, cTnI, CK-MB, and BNP diagnosis of heart failure and for determining the stage of the disease. This single PANI nanowire-based biosensor demonstrated superior biosensing reliability with the feasibility of label free detection and improved processing cost efficiency due to good biocompatibility of PANI to monoclonal antibodies (mAbs). Therefore, this development of single PANI nanowire-based biosensors can be applied to other biosensors for cancer or other diseases.

No MeSH data available.


Related in: MedlinePlus