SPR Sensor

Summary

In this video, Hendri Uranus from the Department of Electrical Engineering at Universitas Pelita Harapan explains the principles of Surface Plasmon Resonance (SPR) sensors and their application in virus detection. SPR works by exciting surface plasmons on a metal surface through light interaction. When a target virus or pathogen binds to a receptor layer, the SPR signal shifts, indicating the presence and concentration of the virus. This technology, used for detecting COVID-19 and other pathogens, offers real-time, specific, and sensitive diagnostic capabilities by analyzing changes in light reflection at different angles.

Takeaways

• 😀 SPR stands for Surface Plasmon Resonance, a phenomenon where light interacts with free electrons in a metal, creating surface waves that can be used to detect various substances.
• 😀 SPR sensors can detect viruses by measuring shifts in the plasmon resonance caused by the binding of viruses to a receptor layer on the metal surface.
• 😀 When light strikes the surface of a metal at a specific angle, it causes a drop in reflectivity at the resonance point, which can be observed and measured.
• 😀 The presence of a virus or other analyte in the surrounding medium causes a shift in the SPR curve, which is proportional to the concentration of the analyte.
• 😀 A receptor layer, typically composed of antibodies, is used to specifically capture the virus, ensuring that the sensor only detects the target analyte.
• 😀 The sensor setup involves a prism coupled with a thin metal film and a receptor layer, with a fluidic system to introduce the sample for testing.
• 😀 As a virus binds to the receptor, the SPR curve shifts, and this shift can be measured to determine the amount of virus present in the sample.
• 😀 Once the receptor layer reaches saturation with the virus, the SPR response curve flattens, providing a quantitative measure of virus concentration.
• 😀 After saturation, if the virus is released or washed off, the SPR curve will decrease, allowing for a confirmation of virus presence and its dissociation rate.
• 😀 SPR sensors are a sensitive, real-time method for detecting viruses, providing a valuable diagnostic tool for viral infections such as COVID-19.
• 😀 The system can be reused multiple times by rinsing the chip, making it an efficient tool for continuous monitoring and detection of viral contaminants.

Q & A

What does SPR stand for, and what is its basic principle?

SPR stands for Surface Plasmon Resonance. It works based on the interaction of free electrons on a metal surface with light (photons). When light strikes the metal surface at a specific angle, it excites surface plasmon waves, which can be detected to observe changes caused by the presence of substances like viruses.

How does the SPR sensor detect substances such as viruses?

The SPR sensor detects substances by observing shifts in the light reflection curve as particles (such as viruses or bacteria) bind to a receptor layer on the sensor surface. These shifts indicate the presence and concentration of the target analyte.

What is the role of the receptor layer in the SPR sensor setup?

The receptor layer, often composed of antibodies, is used to specifically bind to the target analyte (e.g., a virus). This ensures that the sensor responds only to the presence of the desired substance, increasing the specificity of the detection.

What is the significance of the 'critical angle' in SPR?

The critical angle is the angle of light incidence at which total internal reflection occurs. This is when the surface plasmon resonance phenomenon is triggered, allowing the sensor to detect changes in reflection intensity caused by binding events at the sensor's surface.

How does the SPR sensor generate a reflection curve?

The SPR sensor generates a reflection curve by varying the angle of light incidence and measuring the intensity of light reflected from the surface. As the surface plasmon resonance is excited, the curve shows changes in reflection intensity that correspond to the presence of the analyte.

Can SPR sensors detect viruses in real-world applications?

Yes, SPR sensors can detect viruses in real-world applications. In the case of COVID-19, researchers have used SPR to detect the virus directly by passing a sample containing the virus over the sensor. The virus binds to the receptor layer, causing a shift in the reflection curve, which indicates its presence.

What type of samples can be analyzed with an SPR sensor?

SPR sensors can analyze a variety of samples, especially fluids such as body fluids, buffer solutions, and biological samples containing pathogens like viruses, bacteria, or other contaminants.

What happens when the SPR sensor detects a virus?

When the SPR sensor detects a virus, the virus binds to the receptor layer on the sensor's surface, which shifts the reflection curve. The magnitude of this shift provides information about the virus concentration in the sample.

What does the term 'response unit' mean in the context of SPR sensors?

The 'response unit' in an SPR sensor quantifies the shift in the reflection curve caused by the binding of an analyte (e.g., a virus) to the receptor layer. This unit helps to determine how much of the analyte is present in the sample.

How can the SPR sensor system be adjusted for optimal detection?

The SPR sensor system can be adjusted by rotating the prism to find the optimal angle of light incidence for exciting the surface plasmon resonance. This adjustment ensures accurate and sensitive detection of the analyte.