Hi !

Selecting the appropriate molecular weight of PEG is a critical step, as it significantly influences key factors such as nanoparticle coagulation, colloidal stability, and overall performance. I’ve provided answers to your queries, and I’d be glad to see your work progress positively from here:

1. Suitable Molecular Weights of PEG for Coating SeNPs

• PEG with molecular weights between 2–10 kDa is commonly used; 5 kDa strikes a good balance between stability, reduced opsonization, and minimal increase in hydrodynamic size.

2. Best PEGylation Methods for Plant-Mediated SeNPs

• Physical adsorption is simple and preserves biological functionality but is less stable; covalent coupling (e.g., using EDC/NHS chemistry) provides stronger attachment, better stability, and prolonged circulation time.

3. How PEGylation Affects Size, Zeta Potential, and Biological Activity

• Size: PEGylation increases hydrodynamic diameter (by ~10–30 nm depending on PEG MW).
• Zeta potential: It reduces surface charge magnitude (more neutral), enhancing colloidal stability.
• Biological activity: PEGylation may slightly reduce direct cytotoxicity but improves biocompatibility and in vivo stability.

4. Published Protocols or Characterization Strategies

• FTIR: Confirms PEGylation by C–O–C and C–H stretching peaks (~1100 and 2900 cm⁻¹).
• DLS: Tracks size increase and polydispersity index (PDI) after PEGylation.
• Zeta Potential: Indicates colloidal stability shift post-functionalization.
• TEM: Confirms core morphology and uniform PEG layer (indirectly via contrast or shell).
• Research paper you can refer to:

  Article Evaluation of Different Surface Coating Agents for Selenium ...

Dear friend Hafiz Abdul Haseeb

I was intrigued to learn about your work on PEGylation of plant-mediated selenium nanoparticles (SeNPs). PEGylation is indeed a promising strategy to enhance nanoparticle stability and biocompatibility, and I appreciate the innovative approach you are taking.

I am curious about several aspects of your project. Firstly, regarding the molecular weight of PEG, have you considered how different chain lengths might affect the colloidal stability and dispersion of your SeNPs? Lower molecular weights may offer greater flexibility, while higher ones could provide enhanced steric stabilization. What criteria are guiding your selection process?

Additionally, with plant-mediated synthesis, natural compounds present could interact with PEG during functionalization. In your view, what are the relative advantages or limitations of physical adsorption versus covalent coupling for your system, particularly in terms of stability and persistence in biological environments?

I am also interested in how you anticipate PEGylation will influence key physiochemical properties such as size, zeta potential, and biological activity. Do you expect these modifications to impact cellular uptake or other biological interactions? Furthermore, which characterization techniques are you planning to use to confirm successful PEGylation? For example, FTIR could provide evidence of chemical bonding, while DLS and TEM might reveal changes in size and morphology.

If you have identified any literature that closely aligns with your approach, I would be keen to hear about it. It might also be valuable to explore how similar functionalizations have been applied to other metal nanoparticles for additional insights.

Thank you for considering my questions. I look forward to your thoughts and wish you continued success with your research.

Some articles to read/ cite:

Chapter Synthesis Of Manganese Oxide Nanoparticles Using Similar Pro...

Article Hierarchical Ni-Mn Double Layered/Graphene Oxide with Excell...

Best regards,

Kaushik

PEGylation of CdSe quantum dots using silanes has been successful. See 969 of the attached article in which methoxypolyethyleneoxypropyltrimethoxysilane is referenced.