Gel Funnel Specifications

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Technical drawings of the funnel-like gel-stretching apparatus. It is used for radially compressing polyacrylamide gel of diameter d0 into an open-ended NMR tube of internal diameter dN, thus weakly aligning macromolecules inside the hydrogel. After compression, the aspect ratio of the gel is (d0/dN)^3.

The assembly consists of five parts, labeled 1-5:

  1. Funnel
  2. Cylinder
  3. O-ring plug
  4. Brass cap
  5. Brass screw
Two ends of the cylinder have threads so that the funnel and the brass cap can be screwed onto the cylinder for assembly.

In the technical drawing, INSTANCES A, B, C, and D correspond to apparatus dimensions for different degrees of radial compression, yielding the following gel aspect ratios:

INSTANCE Aspect Ratio
A 4.5
B 2.8
C 2.1
D 1.6

Funnels and other accessories can now be purchased from NewEra Research, for information contact


James J. Chou, Sander Gaemers, Bernard Howder, John M. Louis, and Ad Bax. "A simple apparatus for generating stretched polyacrylamide gels, yielding uniform alignment of proteins and detergent micelles" J. Biomol. NMR 21, 377-382 (2001). (302.pdf, 116030 Bytes)

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