C-reactive protein DNA PLGA Research & information: general SPIONs antibody biological receptors biomarker biosensing biosensor biosensors cancer diagnosis carbon nanofiber carbon nanotubes carbon paste electrode carcinoembryonic antigen cell cellulose clinical analysis colorimetric detection cytosensing diagnostics electrochemical (bio)sensor electrochemical impedance electrochemical methods electrospinning encapsulation enzyme exosomes extracellular vesicles