Microcantilever array biosensors for detection and recognition of Gram-negative bacterial endotoxins

• The use of cantilever sensors to detect bacterial endotoxins is proposed.
• Specific antibodies are grown and tested using SDS-PAGE and ELISA methods.
• Self-assembling monolayers are used to immobilize antibodies on sensors.
• Custom-made readout system is used to monitor cantilever array's behavior.
• Endotoxins from strains of Hafnia alvei PCM 1185 and PCM 1186 are recognized.

Gram-negative sepsis is an increasingly common medical problem, in particular in developed countries. Toxic effects associated with Gram-negative sepsis are driven mainly by lipopolysaccharides (endotoxin), a species specific component of the outer membrane of bacterial cell wall. Quick and accurate detection of the endotoxin and determination of the pathogen species responsible for the infection are crucial for prompt and effective treatment. Micromechanical biosensor arrays can be an effective approach for construction of endotoxin (lipopolysaccharides) biosensors. In this work, we present the preparation and application of a microcantilever array for the detection and recognition of Gram-negative bacterial endotoxins. Self-assembling monolayers on sensing elements were functionalized with monoclonal antibodies specific to endotoxins of choice. Purity and cross-reactivity of antibodies were verified using SDS-PAGE and ELISA analyses. A home-made micromechanical sensors analysis platform was used to test the performance of prepared cantilever biosensor arrays. The sensor array was shown to recognize endotoxins from strains of Hafnia alvei PCM 1185 and PCM 1186. The proposed functionalization procedure and the applied measurement system form a promising platform for further investigations, including that of different antigens.