What is polyacrylamide (PAM)?

Polyacrylamide (PAM) is a non-toxic polymer (-CH 2 CHCONH 2 -) formed from an acrylamide subunit, which is a highly water-soluble vinyl monomer 18. Cross-linked PAMs are water-insoluble, and form a soft gel in the presence of water 19.

What is the PAM matrix?

The PAM injection matrix was guided into the X-ray interaction point by helium flow (focusing gas pressure: 1–2 × 10 5 Pa) from the outer capillary of the injector. The PAM matrix was delivered at a stable flow rate of <400 nl/min (Fig. 2a ).

What is a C value in acrylamide methylene bisacrylamide?

The term C refers to the percentage of the total monomer represented by the crosslinker. For example, an 8%, 19:1 (acrylamide/bisacrylamide) gel would have a T value of 8% and a C value of 5%. Upon the introduction of the catalyst, the polymerization of acrylamide and methylene bisacrylamide proceeds via a free-radical mechanism.

What is the diffraction data of the Pam injection matrix?

The diffraction data of the experiment using the PAM injection matrix with the X-ray pluses were collected at the NCI (Nano Crystallography and Coherence Imaging) experimental hutch at PAL-XFEL 28, 30. The X-ray energy was 9.7 keV (1.2782 Å) with a pulse energy of approximately 500 μJ and a repetition rate of 30 Hz.

How do you control pore size of a polyacrylamide gel?

Control of the pore size of a polyacrylamide gel is accomplished by changing the T and C values. With increasing T, the pore size decreases in a nearly linear relationship. Higher percentage gels (higher T), with smaller pores, are used to separate smaller molecules. The relationship of C to pore size is more complex.

What percentage of Pam is in the injection matrix?

PAM fragments and crystal suspensions were mixed with the plunger gently moving back and forth more than 20 times in the two coupled syringe set-up. The final percentage of the crystal pellet was approximately 20–25% in the total injection matrix.