Appeal No. 1999-1384
Application No. 08/583,912
application of 40 µl test solution to obtain a two minute draw-
through time.
The examiner finds (Answer, page 6) that “[i]t would have been obvious to
the ordinarily skilled artisan at the time the instant invention was made to have
substituted the solid phase support of the displacement assay device and
method of Ligler et al. with a porous membrane such as is taught by Kidwell.”
According to the examiner (id.):
The limitation as to the amount of interaction time being no
more than about 15 seconds appears to be a result effective
variable which depends upon pore size of the membrane,
the surface area of the membrane, and the analyte to be
detected ([s]ee Kidwell[,] column 6, lines 22-34), as well as
the flow rate of the system (Ligler et al.) and it would have
been obvious to one having ordinary skill in the art at the
time the invention was made to have designed the system
and method so as to achieve a rapid interaction time and
obtain displacement as desired by Ligler et al. (e.g. column
6, lines 51-54) since it has been held that discovering an
optimum value of a result effective variable involves only
routine skill in the art. In re Boesch, 617 F.2d 272, 205
USPQ 215 (CCPA 1980).
In response, appellants argue (Brief, pages 5-6) that:
To achieve the proper flow rate through the membrane and
thus (in a passive flow system) the correct interaction time of
one to five minutes, Kidwell must use a small pore size for
the supporting membrane or provide a flow-control
membrane of a specified pore size beneath the supporting
membrane (col. 6, lines 3 through 44). The obvious
implication of Kidwell’s teaching is that unless sample flow is
significantly restricted, even gravity-assisted flow through a
transversely positioned antibody-supporting membrane is
too fast to allow an adequate interaction times [sic] for
immunoassays. Therefore Kidwell also teaches against
actively pumping a sample through a transversely positioned
antibody-supporting membrane.
Appellants find (Brief, page 6) that “[t]his teaching against is particularly
pertinent where, as in the claims, the resulting interaction time are [sic] no more
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