Nanomaterials in Biosensing Using Ion Selective Field Effect Transistors and Metal Particles
30 Jul 2008 | Online Presentations | Contributor(s): Nalam Madhusudhana Rao
The multifunctionality, multilayerable architechture and size of nanomaterials offer tremendous opportunities in developing sensing platforms. Ion Selective Field Effect Transistors (ISFET) are solid state and robust pH/ion sensing devices with excellent “voltage vs. ion concentration” characteristics. However, maintaining effective concentrations of enzymes at the sensor gate of an FET device is a challenge. Earlier attempts to develop ISFETs as enzyme based biosensors were reported by crosslinking enzymes on to the surface or by entrapping in a polymer matrix at the gate surface. We attempted a new approach wherein the enzymes are immobilized on magnetic nanoparticles and thereby retaining the enzyme on sensor surface using permanent magnet. Triglycerides could be mesaured in physiological range in small volumes. This platform could be expanded to other analytes such as cholesterol, urea, creatinine etc. We observed nanoparticle surface induced inactivation of proteins. Efforts in defining the stability in protein upon interaction with surfaces would be discussed.