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Updated: May 5, 2026
Attaching Biological Probes to Silica Optical Biosensors Using Silane Coupling Agents
Published on: May 1, 2012
Non-faradaic electrochemical biosensor based on APTES-modified core-shell silica nanoparticles
Munira S Albuaimi1, Ahmed Mohamed El-Toni2, Mahmoud Al-Gawati3
1Department of Biomedical Technology, College of Applied Medical Sciences, King Saud University, P.O. Box 10219, Riyadh 11433, Saudi Arabia; King Salman Center for Disability Research, Riyadh 11614, Saudi Arabia; Biological and Environmental Sensing Research Unit, King Abdullah Institute for Nanotechnology, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
This study presents SiO2 nanoparticles biosensors for detecting human cytomegalovirus, a cause of newborn disability. Functionalization strategies improved detection limits for this critical diagnostic tool.
Area of Science:
- Nanotechnology
- Biosensing
- Materials Science
Background:
- Human cytomegalovirus (HCMV) is a significant cause of congenital disabilities in newborns.
- Non-faradaic electrochemical impedance spectroscopy (EIS) offers a label-free detection method for pathogens.
- SiO2 nanoparticles present a promising platform for biosensor development due to their tunable properties.
Purpose of the Study:
- To develop and optimize SiO2 nanoparticles-based biosensors for the non-faradaic EIS detection of HCMV.
- To investigate the impact of APTES functionalization concentration and method on biosensor performance.
- To enhance the sensitivity and limit of detection for HCMV diagnostics.
Main Methods:
- Fabrication of mesoporous SiO2 nanoparticles via sol-gel method.
- Functionalization of SiO2 nanoparticles with varying concentrations of APTES on interdigitated gold electrodes.
- Immobilization of UL83-antibodies using glutaraldehyde for antigen capture.
- Characterization of surface coverage using XPS and EIS.
- Optimization of APTES functionalization approach (pre- vs. post-casting).
Main Results:
- Optimized APTES functionalization improved SiO2 nanoparticle coverage on the electrode surface.
- Increased APTES concentration led to decreased sensitivity (13.99 to 10.78 nF/ln(ng/mL)).
- Limit of detection for HCMV was significantly improved, from 6 ng/mL to 2 ng/mL.
- Functionalization after nanoparticle drop casting yielded superior surface coverage and biosensing performance.
Conclusions:
- SiO2 nanoparticles functionalized with APTES are effective for non-faradaic EIS detection of HCMV.
- The method of APTES functionalization critically impacts biosensor performance, with post-casting application being superior.
- This optimized biosensor demonstrates improved detection limits for HCMV, aiding in early diagnosis and prevention of newborn disabilities.
