Antibody-Functionalized SERRS Nanoprobe Based Imaging: A Highly Sensitive Raman-imaging Technique to Detect Metastatic Ovarian Cancer In Vivo

Surface-Enhanced Resonance Raman Scattering or SERRS technique utilizes analyte molecules bearing a Raman reporter dye to interact with incident light and cause inelastic light scattering.

Begin with an injection mix containing two types of nanoprobes - targeted nanoprobes tagged with specific anti-receptor antibodies carrying a distinct reporter dye and non-targeted control nanoprobes possessing a different reporter dye. Inject this suspension into the peritoneal cavity of a female mouse bearing metastasized ovarian cancer. Allow sufficient time for the nanoprobes to distribute within the peritoneal cavity.

The targeted anti-receptor antibody functionalized nanoprobes bind to their specific receptors overexpressed on ovarian cancer cells, while the non-targeted nanoprobes adhere non-specifically to the visceral surface.

Euthanize the mouse and secure it on an imaging platform in a supine position. Surgically incise its abdomen and remove the intestines to expose the peritoneal cavity. Image the mouse under a Raman microspectrophotometer.

On irradiation with laser light, both types of nanoprobes cause the incident light to scatter differently, each generating unique spectral signatures. Process the spectra to determine the relative abundance of nanoprobes to differentiate the cancer cells from the visceral background.

For nanoprobe injection, spin down both nanoprobe flavors and resuspend the pellets in fresh MES buffer at a 600 picomolar concentration. Mix the nanoparticles and load 1 milliliter of the resulting solution into one 1 milliliter syringe equipped with a 26 gauge needle per mouse and intraperitoneally inject the entire volume into the abdomen of each mouse. Then, gently massage the abdomen to distribute the nanoparticles throughout the peritoneal cavity.

After at least 25 minutes, secure the limbs of a euthanized injected animal onto a surgical platform and use serrated forceps and dissection scissors to remove the skin to expose the peritoneum. Incise the peritoneum. Attach the peritoneal flaps to the platform and wash the inside of the peritoneal cavity with at least 60 milliliters of PBS. Then, transfer the platform to a Raman microspectrophotometer with an upright optical configuration in a motorized stage and image the abdomen under the appropriate imaging parameters.

It is crucial that the focal plane for the Raman scan is on the surface of most of the viscera. If the organs are out of plane, the acquired signal will not be useful.

• Surface-Enhanced Resonance Raman Scattering (SERRS) - Technics to cause inelastic light scattering using dye.
• Targeted Nanoprobes - Tagged with antibodies to detect specific receptors.
• Non-targeted Nanoprobes - Adhere non-specifically to detect control samples.
• Raman Microspectrophotometer - Device used to generate unique spectral signatures.
• Spectral Signature - Unique light scattering pattern for distinguishing different materials.

• Introduce SERRS – Technique to analyze molecules via light scattering (e.g., SERRS).
• Explain Nanoprobes – Role of targeted and non-targeted nanoprobes in disease detection (e.g., ovarian cancer).
• Using Raman Microspectrophotometer – Imaging and analysis method (e.g., spectral signature).
• Connecting to Experiment – Approach to differentiate cancer cells via nanoprobes.

• [Question 1] What is SERRS and how does it use dyes?
• [Question 2] How do targeted and non-targeted nanoprobes work?
• [Question 3] How does a Raman microspectrophotometer generate spectral signatures?

• Practical Applications – Non-invasive cancer cell detection methodology (e.g., SERRS).
• Industry Impact – Advancement in cancer research and diagnostics (e.g., healthcare).
• Societal Importance – Enhancing early detection and treatment of diseases (e.g., ovarian cancer).
• Scientific Advancements – Contributions to photonic and biomedical research.