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PLASMONIC BIOSENSORS - Coggle Diagram
PLASMONIC BIOSENSORS
INTRODUCTION
Classification
- use thin metallic films
- use individual inorganic plasmon resonant nanostructures
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LOCALIZED SURFACE PLASMONS
Collective oscillation of the free surface electrons in response to the oscillating electric filed of the light
- Designed to be RI sensors
- Used as visual tags as an alternative to fluorophore tags or thera peutic egents for cancer treatment
- Single Nanoparticle Localized Surface Plasmon Resonance Sensors - Single plasmon resonant NPs
- Monitoring nuclease activity on DNA - coated gold NPs
- Plasmonic enzyme-linked immunosorbent assay (ELISA)
- Ensemble Localized Surface Plasmon Resonance Sensors
- Transmission LSPR spectroscopy probes hundreds-millions at a time
- Do not require extensive temperature
- Comprised of a high density of plasmon resonant nanostructures immobilized onto a glass slide or similar transparent substrate
- Using high throughput optical measurements are those done in a reflected optical geometry
- Plasmon Resonant Nanoparticles as Labels
- Use fluorophores is straightforward to conjugate gold and silver NPs
- Can be seen using dark field microscopy
- Lateral flow assay
+Step 1: Depositing a sample solution onto a chromatographic membrane strip
+Step 2: Sample flows via capillary action through a region of the membrane containing antibody labeled NPs
+Step 3: These NPs are carried with the sample solution to a region further along on the membrane strip that contains immobilized secondary antibody for the antigen of interest
+Step 4: When antigen is present in the sample solution a dark line appears on the strip in a pre-determined location due to immobilization of the plasmon resonant NPs.
- Limitation: quantitative data from visual-only detection
- Plasmon Resonant Nanoparticles Cancer Therapeutics
- NPs are localized to cancerous tumor cells and then are heated => virtue of absorption of illumination light et their LSPR wavelength => promotes cancer cell death
- NPs are used as carries of drug molecules (such as silencing RNA) to tumor cells to inhibit tumor cell growth => NPs are localized to tumor cells, the drugs conjugated to their surface can be released by intense illumination at the NP LSPR wavelength and subsequently promote cell death within tumor
PLASMONIC NANOPORES
Use in thin metal films for sensing combines characteristics of progating SPR and LSPR sensing
Use Extraordinary optical transmission (EOT)
Monitoring the intensity changes of light passing through pores or by monitoring shifts in the spectrum of the light transmitted through the pores
- First, pores can be interrogated with a simple collinear optical configuration with few optics
- Second, pores are nano-sized
- Third, nanopore arrays are fairly easy to create with standard patterning processes
- Fourth, the use of pores as a sensing element enables flow-through studies that can improve limits of detection in cases where sensing is otherwise mass transport limited.
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