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Updated: Apr 16, 2026
Fabrication of Carbon Nanotube High-Frequency Nanoelectronic Biosensor for Sensing in High Ionic Strength Solutions
Published on: July 22, 2013
Protein functionalized carbon nanotubes-based smart lab-on-a-chip
Md Azahar Ali1, Pratima R Solanki2, Saurabh Srivastava3
1‡Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Ordnance Factory Estate, Yeddumailaram, Hyderabad, Andhra Pradesh 502205, India.
Insights
A novel biosensor using carbon nanotubes-nickel oxide nanocomposite detects low-density lipoprotein (LDL) with high sensitivity. This impedimetric lab on a chip (iLOC) shows promise for in vivo diagnostics and improved stability.
Area of Science:
- Biomedical Engineering
- Nanotechnology
- Analytical Chemistry
Background:
- Cardiovascular diseases are a major health concern, often linked to elevated low-density lipoprotein (LDL) levels.
- Accurate and sensitive detection of LDL is crucial for early diagnosis and management of cardiovascular risks.
- Existing diagnostic methods can be time-consuming, expensive, or require complex sample preparation.
Purpose of the Study:
- To develop a label-free impedimetric lab on a chip (iLOC) for sensitive and rapid detection of LDL.
- To investigate the potential of a carbon nanotubes-nickel oxide (CNT-NiO) nanocomposite functionalized with antiapolipoprotein B for LDL sensing.
- To evaluate the cytotoxicity and electrochemical performance of the developed iLOC system.
Main Methods:
- Fabrication of a CNT-NiO nanocomposite and functionalization with antiapolipoprotein B (AAB).
- Assembly of a microfluidic electrode using polydimethylsiloxane microchannels.
- Cytotoxicity assessment using MTT assay on A549 lung cancer cell line.
- Characterization of the electrode surface using X-ray photoelectron spectroscopy.
- Electrochemical analysis using chronocoulometry and impedance spectroscopy for binding kinetics and activity.
Main Results:
- The CNT-NiO nanocomposite exhibited lower cytotoxicity compared to individual CNTs at tested concentrations.
- The iLOC demonstrated high sensitivity (5.37 kΩ (mg/dL)(-1)) and a low detection limit (0.63 mg/dL) for LDL detection within a wide range (5-120 mg/dL).
- Binding kinetics revealed a high association rate constant (8.13 M(-1) s(-1)) for LDL antigen-antibody interactions.
Conclusions:
- The developed CNT-NiO based iLOC offers a sensitive, stable, and reproducible platform for label-free LDL detection.
- The biosensor shows significant potential for in vivo diagnostics and improved cardiovascular disease monitoring.
- The study highlights the advantages of using CNT-NiO nanocomposites in electrochemical biosensing applications.
Abstract:
A label-free impedimetric lab on a chip (iLOC) is fabricated using protein (bovine serum albumin) and antiapolipoprotein B functionalized carbon nanotubes-nickel oxide (CNT-NiO) nanocomposite for low-density lipoprotein (LDL) detection. The antiapolipoprotein B (AAB) functionalized CNT-NiO microfluidic electrode is assembled with polydimethylsiloxane rectangular microchannels (cross section: 100 × 100 μm). Cytotoxicity of the synthesized CNTs, NiO nanoparticles, and CNT-NiO nanocomposite has been investigated in the presence of lung epithelial cancer A549 cell line using MTT assay. The CNT-NiO nanocomposite shows higher cell viability at a concentration of 6.5 μg/mL compared to those using individual CNTs. The cell viability and proliferation studies reveal that the toxicity increases with increasing CNTs concentration. The X-ray photoelectron spectroscopy studies have been used to quantify the functional groups present on the CNT-NiO electrode surface before and after proteins functionalization. The binding kinetic and electrochemical activities of CNT-NiO based iLOC have been conducted using chronocoulometry and impedance spectroscopic techniques. This iLOC shows excellent sensitivity of 5.37 kΩ (mg/dL)(-1) and a low detection limit of 0.63 mg/dL in a wide concentration range (5-120 mg/dL) of LDL. The binding kinetics of antigen-antibody interaction of LDL molecules reveal a high association rate constant (8.13 M(-1) s(-1)). Thus, this smart nanocomposite (CNT-NiO) based iLOC has improved stability and reproducibility and has implications toward in vivo diagnostics.
