I have my bare SPR gold chips that I'd like to conjugate some PLL coated nanoparticles on. From what I've been reading I understand that I need to functionalize my gold surface with Thiolated PEG with COOH group, (I'm not sure if I can make that or should I buy it? ), activate it with EDC -NHS chemistry and then conjugate with PLL particles which have an amine group (NH2). I have two questions:
1. Can the experiment be done through SPR? Or should I go over 48 hours of conjugation chemistry with just dip coating?
2. I find very contradictory information on how to a. make the thiolated PEG, b. how to conjugate the COOH group to the gold and c. the concentration and duration of incubation in EDC prior to addition of PLL particles.
Any help , paper, information will be highly appreciated. Thank you,
I have to say i did not any of the questions and I am not a chemist. I lloked through my literature and this may be of help.
1) I did not do it myself but from what i know it is simpler to make the SAM out side the instrument in order to have longer incubation times. The assembly proces is fairly fast but longer incubations give better quality surface with respect to the packing and chain orientation. Ref: Bain, Troughton, Tao, Evall, Whitesides and Nuzzo; Formation of monolayer films by the spontaneous assembly of organic thiols from solution onto gold; Journal/Journal of the American Chemical Society; (111) 321-335; 1989
2a) I would buy it form a chemical supplier. Maybe you can also buy the SH-PEG-COOH or with a group that is easily converted to –COOH.
2b) one way to do it: Chatelier, Gengenbach, Griesser, Brigham and O'Shannessy; A general method to recondition and reuse BIAcore sensor chips fouled with covalently immobilized protein/peptide; Journal/Analytical Biochemistry; (229) 112-118; 1995.
2c) Standard activation of 7 minutes is in general enough. Immobilization conditions are investigated by Johnsson, Lofas and Lindquist; Immobilization of proteins to a carboxymethyldextran-modified gold surface for biospecific interaction analysis in surface plasmon resonance sensors; Journal/Analytical Biochemistry; (198) 268-277; 1991.