Hey there Aditya Raj! When it comes to conjugating a monoclonal antibody to gold nanoparticles, it's crucial to follow a reliable protocol to ensure efficiency. Here's a concise guide for your queries:

1. **Conjugation Protocol:**

There isn't a one-size-fits-all protocol, as it can depend on your specific antibody and nanoparticles. However, a commonly used method involves surface modification of nanoparticles followed by antibody binding. I'd recommend checking recent literature or established protocols in your field for the most suitable approach.

2. **Storage in PBS:**

Storing your conjugate in PBS is generally acceptable, but the stability can vary. Ensure the pH is suitable, and consider adding a protein stabilizer like BSA. Testing over time and monitoring any changes in activity or aggregation will give you Aditya Raj a better idea of the storage limits.

3. **Microbial Growth Prevention:**

Sodium azide is a common microbial growth inhibitor, but if you're looking for alternatives, consider adding antimicrobial agents like thimerosal or storing at lower temperatures. However, be mindful of any impact on your assay.

4. **Conjugation Efficiency Check:**

Assessing conjugation efficiency can involve techniques like UV-Vis spectroscopy or dynamic light scattering to measure changes in particle size. ELISA can also be adapted to quantify antibody binding. Experimentation and optimization are key here.

5. **ELISA on 96-Well Plate:**

For ELISA, coat the plate with your conjugate, block, and then incubate with your antigen. Detection can involve secondary antibodies or streptavidin conjugated to an enzyme. Again, protocol details may vary, so refer to literature or similar studies for a solid starting point.

6. **Alternative Antigen Detection:**

Beyond ELISA, other methods like lateral flow assays or surface plasmon resonance (SPR) can be considered for detecting antigens with gold-conjugated antibodies. Each method has its advantages and limitations, so choose based on your specific requirements.

Remember, these suggestions provide a starting point, and it's essential to adapt based on your experimental setup and results. Happy experimenting Aditya Raj!

#query

For now I don't have sodium azide, 2-chloroacetamide ir thermosiol?

Which one is the best?

Can I use ampicillin. What percentage of ampicillin is suitable for storage of mAb for longer time?