Biosensors and nanobiosensors for rapid point of care measurement of biomarker proteins (original) (raw)

Meta Gene

Abstract

Abstract The current gold standard for protein biomarker measurement is the ELISA, which shows good sensitivity and specificity but is typically quite slow and requires expensive and complex equipment. For applications such as early cancer diagnosis, this may limit access, whilst for critical conditions such as acute kidney injury (AKI), sepsis, stroke then rapid measurement has the potential to drive the clinical response. Other applications such as immediate confirmation of bacterial Vs viral infection to inform antibiotic prescribing, also require a fast analysis. Biosensors offer the prospect of reagent-less, processing-free measurements at the patient's bedside. We have fabricated electrochemical immunosensors against a wide range of medical analytes; such sensor operate by virtue of an immobilized bioreceptor, typically an antibody or antibody fragment, or more recently a synthetic binding protein (Affimer) onto an electrode surface. Sensor readout after exposure to the biomarker, in blood, urine or other bio-fluid is then by electrochemical impedance measurement. We have also developed lanthanide ion doped nanoparticles, typically 20–40 nm diameter which are surface-functionalized with antibodies or Affimers. Here, readout after biomarker presentation is via alteration of luminescence intensity, either quenching or enhancement. Also since the nanobiosensors are in suspension and the emission profile can be tuned, then real time measurement, e.g. of the AKI biomarker NGAL in urine should be possible. With all of these devices, the surface nanostructure is absolutely key to performance and this will be discussed.

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