Detection of typhoid fever by diatom-based optical biosensor

Area of Science:

• Materials Science
• Biotechnology
• Environmental Science

Background:

• Typhoid fever, caused by Salmonella typhi, remains a significant global health concern.
• Accurate and rapid detection of S. typhi is crucial for effective disease management and public health surveillance.
• Existing diagnostic methods can be time-consuming or require specialized laboratory equipment.

Purpose of the Study:

• To develop a highly sensitive and specific immunocomplex-based optical biosensor for the detection of Salmonella typhi.
• To utilize surface-modified diatom substrates as a novel platform for biosensor development.
• To evaluate the performance of the developed biosensor for potential environmental monitoring applications.

Main Methods:

• Covalent immobilization of Salmonella typhi antibodies onto crosslinked diatom substrates using glutaraldehyde.
• Photoluminescent (PL) studies to assess the specificity of the biosensor against S. typhi and non-complementary antigens (Escherichia coli).
• Determination of the detection limit of the immunocomplexed biosensor.

Main Results:

• The conjugated diatom substrates exhibited excellent specificity, distinguishing between complementary (S. typhi) and non-complementary (Escherichia coli) antigens.
• The immunocomplexed biosensor achieved a low detection limit of 10 pg.
• The biosensor's performance is attributed to the diatom frustules' large surface-to-volume ratio, photoluminescent properties, and biocompatibility.

Conclusions:

• Surface-modified diatom substrates provide a suitable and effective platform for developing immunocomplex-based optical biosensors.
• The developed biosensor demonstrates high sensitivity and specificity for Salmonella typhi detection.
• This technology holds potential for the environmental monitoring of water-borne pathogens like S. typhi.