Antibodies are widely recognized as the gold standard for biological recognition, but unfortunately these molecules are fragile, unstable and short-lived in harsh environments. This issue has been overcome by the use of single domain antibody fragments (sdAb) or Nanobodies which are highly stable. However, determining the binding properties of these molecules under harsh conditions such as pH extremes, high temperature, high salt conditions, etc. has not been easy to accomplish because current biophysical methods are not compatible with highly complex matrices. Nevertheless, researchers from the US Air Force Research Laboratory were able to use MicroScale Thermophoresis (MST) to measure the binding affinity of Nanobodies in a highly complex environment — jet fuel.
Microbial contaminants in aviation fuels are a concern because of their potential to degrade the fuel, accelerate corrosion in the fuel tank, plug fuel filters and threaten flight safety. Methods for the detection of microorganisms in fuels have historically included laborious and rather slow techniques such as the classic culture in agar media or molecular-based methods such as genomic or metagenomics analyses.
The US Air Force Research Laboratory took advantage of the high affinity, selectivity, sensitivity and stability of Nanobodies for improving the existing methods. However, determining their binding properties under such harsh environments has not been widely employed because biophysical methods such as surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC), are not compatible with highly complex matrices.
This study demonstrated the ability of Nanobodies to recognize their target in this complex environment and suggests that Nanobodies may have the robustness in affinity to be applied in real world fuel tank biosensors for early detection of biocontamination. Moreover, this study highlights the broad applicability of MST, a technology utilized by the Monolith system, since harsh samples that require laborious cleanup for use in standard methods of biophysical characterizations can be used directly in disposable glass capillaries and with no need of immobilization.
To read the complete study, click here.