Fiber optic particle plasmon resonance (FOPPRTM) is a technology combining optical waveguides with noble metal nanoparticles for the sensitive and reliable detection of molecules. In FOPPRTM, gold nanoparticles (AuNPs) are in close proximity to an unclad optical fiber. As light propagates within the optical fiber, total internal reflection (TIR) results in an evanescent field that induces the AuNPs to undergo particle plasmon resonance (PPR).
As a derivation of surface plasmon resonance (SPR), PPR of noble metal nanoparticles is the collective oscillation of conductive electrons at the nanoparticle surface in response to incident light of a particular wavelength. The extreme sensitivity of this optical property to changes in the surrounding environment makes FOPPRTM an ideal technology for monitoring real-time interactions between a wide range of molecular species, including but not limited to organic drugs, oligonucleotides, proteins, and viruses.
Molecular detection is achieved through the capture of free-flowing analytes by bioreceptors chemically bound to the FOPPRTM sensing surface. As target analytes are introduced to the sensing surface by the sample fluid, binding interactions between analytes and bioreceptors lead to a change in refractive index near the sensing surface. This refractive index change local to the sensing surface results in an immediate change in optical response proportional to the mass concentration of bound analytes. The label-free and biointeraction-based detection of FOPPRTM enables a wide range of applications in biochemical research and development.