Ex Parte Hatcher et al

Board of Patent Appeals and Interferences

May 29, 2012

10616884 (B.P.A.I. May. 29, 2012)

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________

Ex parte BRIAN M. HATCHER, ANTHONY BRENNAN,
BRIAN CUEVAS, and CHARLES SEEGERT
__________

Appeal 2011-001270
Application 10/616,884
Technology Center 1600
__________

Before TONI R. SCHEINER, DEMETRA J. MILLS, and STEPHEN WALSH,
Administrative Patent Judges.

SCHEINER, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134 from the final rejection of
claims 11-39 and 41-44, directed to a bioactive glass composite, and
methods of making and using it. The Examiner has rejected the claims on
the grounds of anticipation and obviousness. We have jurisdiction under
35 U.S.C. § 6(b).
We reverse.
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STATEMENT OF THE CASE
“The use of bioactive glass fibers as tissue engineering scaffolds for
the regeneration of new bone offers a number of advantages” (Spec. ¶ 5).
For example, “[t]he bioactive glass fibers can undergo a series of chemical
reactions leading to the precipitation of a hydroxyapatite (HA) layer on their
surface, resulting in a chemical bond to the host tissue” (id.).
“Bioactive glass fibers have a relatively high silica content . . . [and]
extremely high melt viscosities” (id. at ¶ 6). Thus, “Na2O and CaO are
usually necessary coreactants . . . to adjust the viscosity to levels compatible
with fiber pulling” (id.). “However, the high concentration of Na2O and
CaO in bioactive glasses induces crystallization, which ultimately limits the
biological activity” of the glass fibers (id.).
One way to overcome this problem is through the use of
a sol-gel process, as opposed to a melt process, to produce
fibers. The sol-gel process uses lower processing temperatures
which can reduce crystallization. A sol-gel process involves
reactions of hydrolysis and condensation on metal alkoxides
that lead to the formation of inorganic chains, rings, and
clusters. These reactions can be controlled to produce the
required sol structure (colloidal suspension) necessary to
fabricate materials such as fibers, films, powders, and gels.
(Id. at ¶ 7.)
Claims 11-39 and 41-44 are pending and on appeal. Claims 1-10 are
also pending, but have been withdrawn from consideration. Claim 40 has
been canceled. (App. Br. 2.) Claims 11 and 36 are representative:
11. A bioactive glass composite, comprising:
a biocompatible polymer,
a bioactive glass including at least one calcium, and at least one
phosphorous molecular species;
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the biocompatible polymer being reacted with the bioactive glass,
wherein said calcium and said phosphorous molecular species are not
crystalline.
36. A method of forming a bioactive glass, comprising the steps of:
mixing a biocompatible polymer, a gelable inorganic base material,
and at least one calcium and phosphorous molecular species, and
hydrolizing said mixture, wherein said calcium and said phosphorous
molecular species are not crystalline.
The claims stand rejected as follows:
Claims 11, 13, 21-25, 28, 30, 34, 36, 37, 39, 41, 42, and 44 under 35
U.S.C. § 102(a) as anticipated by Ducheyne '990 (US 6,328,990 B1, issued
December 11, 2001) (Ans. 3-4).
Claims 11, 13, 21-29, 34-39, 41, 42, and 44 under 35 U.S.C. § 103(a)
as unpatentable over Ducheyne '990 and Ducheyne '453 (US 5,591,453,
issued January 7, 1997).
Claims 11, 12, 14, 18-20, 30, and 33 under 35 U.S.C. § 103(a) as
unpatentable over Ducheyne '990 and Shikinami (5,711,960, issued January
27, 1998).
Claims 11-17, 28-32, 34-36, 38, 41, and 42 under 35 U.S.C. § 102(b)
as anticipated by Marcolongo (US 5,721,049, issued February 24, 1998)
(Ans. 4-5).
REJECTIONS BASED ON DUCHEYNE '990
There are three separate rejections of the claims based in whole, or in
part, on Ducheyne '990, but the dispositive issues in all three are the same,
so we will discuss them together.
Appellants emphasize that the claims require a reaction between the
biocompatible polymer and the bioactive glass to form a composite material,
and also require that the calcium and phosphorous molecular species are not
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crystalline (App. Br. 10). Appellants contend that the composite disclosed
in Ducheyne '990 contains crystalline calcium and phosphorous (id.).
Moreover, Appellants contend that Ducheyne '990‟s composite is made by
“blending crystalline glass powders with a polymer” (id.), and Ducheyne
'990 “does not teach that the glass powder is reacted with the polymer” (id.
at 11).
The Examiner‟s position is that Ducheyne '990 “teaches a bioactive
glass composite identical to the instant claims” (Ans. 10), since the prior art
composite “comprise[s] the same components combined in the same way for
the same purpose” (id.).
The issues raised by the rejections over Ducheyne '990 are:
Has the Examiner established an adequate factual basis to support the
finding that the prior art composite contains calcium and phosphorus
molecular species that are not crystalline?
Has the Examiner established an adequate factual basis to support the
finding that the bioactive glass and the polymer react with each other to form
the prior art composite?
Findings of Fact
1. The Specification discloses a composite material produced
according to a sol-gel process comprising “mixing a biocompatible polymer,
a gelable inorganic base material, and at least one calcium and phosphorous
molecular species, and hydrolyzing the mixture” (Spec. ¶ 25).
2. The Specification teaches that:
A sol-gel process involves the evolution of inorganic
networks through the formation of a colloidal suspension (sol)
and gelation of the sol to form a network in a continuous phase
(gel). The precursors for synthesizing these colloids include a
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metal or metalloid element surrounded by various reactive
ligands. Metal alkoxides are the most popular sol-gel
precursors because they react readily with water. The most
widely used metal alkoxides are the alkoxysilanes, such as
tetramethoxysilane (TMOS) and tetraethoxysilane (TEOS).
(Spec. ¶ 57.)
3. The Specification explains that “[t]hree reactions are generally
used to describe the sol-gel process: hydrolysis, alcohol condensation, and
water condensation” (Spec. ¶ 58).
“Generally, the hydrolysis reaction, through the addition of water,
replaces alkoxide groups (OR) with hydroxyl groups (OH). Subsequent
condensation reactions involving the silanol groups (Si-OH) produce
siloxane bonds (Si-O-Si)” (id. at ¶ 59). “[B]ecause water and alkoxides are
immiscible, a mutual solvent is preferably utilized, such as an alcohol” (id.).
The polymer, “in solution with a diluent, such as ethanol (EtOH), and
an acid catalyst, such as hydrochloric acid” (id. at ¶ 61), “can then be mixed
with the alkoxide solution” and “[a]t least one phosphorous source, such as
TEP, and at least one calcium source, such as calcium chloride dehydrate,
can be added to the mixture” (id. at ¶ 62).
The bioactive glass and polymer mixture “is then further reacted to
form a sol[-gel] solution” (id.), from which various composite forms, such as
fibers, coatings, and powders, are prepared (id. at ¶ 64).
4. Ducheyne '990 discloses a “bioactive, degradable composite
material” which “may be used in tissue engineering for implantation or as a
microcarrier for delivery of drugs” (Ducheyne '990, col. 2, ll. 10-15). “[T]he
composite is made from mixing a modified bioactive glass powder with a
poly(lactic co-glycolic acid) polymer matrix” (id. at col. 2, ll. 12-13).
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5. The unmodified glass powder disclosed in Ducheyne '990 has
an initial composition of 45% SiO2, 24.5% CaO, 24.5% Na2O, and 6% P2O5
(Ducheyne '990, col. 2, ll. 55-57). Neither the Examiner nor Appellants
have addressed the nature and/or physical form of the calcium and
phosphorus species in the unmodified glass powder.
6. Ducheyne '990 teaches that “the presence and formation of
calcium hydroxyapatite at [an] implant-bone interface is critical for bone
bonding and is one of the key features necessary for successful bioactive
bone implants” (Ducheyne '990, col. 1, ll. 41-44). Accordingly, Ducheyne
'990 discloses modifying the glass powder (before mixing it with the
polymer matrix to form the composite) by immersing the glass powder in a
simulated physiological solution, which “mimics the ion concentration in
body fluid,” and examining the glass powder for the formation of calcium
hydroxyapatite layers on the glass powder after 1 hour, 6 hours, 1 day, and 3
days of immersion (id. at col. 1, ll. 47-50; col. 2, ll. 65-67; col. 3, ll. 1-21).
After immersion in simulated physiological solution for 6
hours, amorphous calcium phosphate was formed [on the glass
powder] . . . . After immersion for 1 day, . . . the presence of
crystalline calcium phosphate ceramic phase [was detected] . . .
[and] identified as carbonated calcium hydroxyapatite. . . .
When bioactive glass particles were used without modification
in the preparation of the composites, the composite material
surface was severely cracked. It was found unexpectedly that
this problem could be avoided by pre-immersing the glass
powders. For instance, bioactive glass particles immersed for 3
days were used in preparation of microspheres of the composite
material of the present invention.
(Id. at col. 3, ll. 1-21.)
7. Ducheyne '990‟s composites are made by a solid-in-oil-in-water
method (Ducheyne '990, col. 2, l. 37). Briefly, in one working example, a
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polymer (polylactic acid (PLA)) was dissolved in methylene chloride and
mixed with the modified bioactive glass powder, and then added drop by
drop into a polyvinyl alcohol solution, to form microspheres (id. at col. 3, ll.
35-44).
8. According to Ducheyne '990, analysis of the resultant
microspheres showed that the modified glass powder was “distributed in the
outer polymeric shell of the [composite] microsphere” (Ducheyne '990, col.
3, ll. 50-51), and was “embedded in the porous polymer matrix” (id. at col.
3, l. 54).
Discussion
Independent claim 11 recites that “the biocompatible polymer . . . [is]
reacted with the bioactive glass,” while independent claim 36 requires
“mixing a biocompatible polymer, [and] a gelable inorganic base material
. . . and hydrolyzing said mixture” (emphasis added). Both claims require
calcium and phosphorous molecular species that “are not crystalline.”
Appellants contend that the composite disclosed in Ducheyne '990
contains crystalline calcium and phosphorous (App. Br. 10-11). Moreover,
Appellants contend that the prior art composite is made by “blending
crystalline glass powders with a polymer” (id. at 10), and Ducheyne '990
“does not teach that the glass powder is reacted with the polymer” (id. at
11), i.e., the reference “is silent as to a reaction between the glass powder
and the polymer” (id.).
The Examiner‟s position is that Ducheyne '990 “teaches a bioactive
glass composite identical to the instant claims” (Ans. 10), since the prior art
composite “comprise[s] the same components combined in the same way for
the same purpose” (id.).
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First, the Examiner has not established an adequate factual basis to
support the finding that the prior art composite contains non-crystalline
calcium and phosphorous. It is true that Ducheyne '990 examined glass
powders after 1 hour, 6 hours, 1 day, and 3 days of immersion in a simulated
physiological solution, and a layer of amorphous calcium phosphate was
observed on the glass powder after 6 hours of immersion (Ducheyne '990,
col. 2, ll. 65-67; col. 3, ll. 1-10; FF6). However, the Examiner has not
established that glass particles coated with amorphous calcium phosphate
were ever used to prepare the composite. Rather, Ducheyne '990 discloses
that the surface of composite material made by mixing unmodified glass
powder with polymer “was severely cracked” (id. at col. 3, ll. 14-16; FF6),
but “this problem could be avoided by pre-immersing the glass powders” in
simulated physiological solution (id. at col. 3, ll. 17-18; FF6). Ducheyne
'990 explicitly discloses that “bioactive glass particles immersed for 3 days
were used in preparation of microspheres of the composite material of the
present invention” (id. at col. 3, ll. 17-21; FF6).
Second, the Examiner has not established that the composite
disclosed in Ducheyne '990 and the claimed composite “comprise the same
components combined in the same way” (Ans. 10). We note, for instance,
that the prior art composite was made by mixing modified glass powder with
a polymer matrix (FFs 4, 7). After mixing the glass powder with the
polymer matrix, the mixture was added, drop by drop, into a polyvinyl
alcohol water solution, to form microspheres (FF7). There is no explicit
disclosure of a reaction between the modified glass powder and the polymer,
and the modified glass powder is simply described as “distributed in the
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outer polymeric shell of the [composite] microsphere” and “embedded in the
porous polymer matrix” (Ducheyne '990, col. 3, ll. 50-51, 54; FF8).
The present Specification, on the other hand, discloses a composite
made by mixing a gelable inorganic base material (that will eventually
become a bioactive glass) and a dissolved polymer, wherein the components
are “further reacted to form a sol solution” (Spec. ¶ 64; FF3), in a “process
[which] involves the evolution of inorganic networks through the formation
of a colloidal suspension (sol) and gelation of the sol to form a network in a
continuous phase (gel)” (Spec. ¶¶ 6, 7, 15, 57, 58, 64; FFs 2, 3).
The basis of the Examiner‟s finding that the bioactive glass and the
polymer in the prior art composite are reacted together is the underlying
finding that the prior art and present composites are made from the same
components in the same manner. Comparison of the two methods shows
that this is not the case. Therefore, the Examiner has not established an
adequate factual basis to support a finding that Ducheyne '990 implicitly or
inherently “teaches that the polymer and bioglass are reacted together in
order to form the composite” (id.).
Accordingly, the rejections of the claims based on Ducheyne '990 are
reversed.
REJECTION BASED ON MARCOLONGO
Claims 11-17, 28-32, 34-36, 38, 41, and 42 stand rejected as
anticipated by Marcolongo.
The issue raised by this rejection is whether the Examiner has
established that Marcolongo discloses a composite in which a bioactive glass
and a biocompatible polymer are reacted together.
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Briefly, Marcolongo discloses composite materials in which “a braid
or mesh of interwoven bone bioactive glass or ceramic fibers and structural
fibers is impregnated with a polymeric material to provide a composite of
suitable biocompatibility and structural integrity” (Abstract).
Here, the Examiner does not find that Marcolongo meets “the claim
limitation drawn to the biocompatible polymer reacting with the bioactive
glass compound” (Ans. 5). Rather, the Examiner‟s position is that “such a
limitation does not differentiate the claims over the prior art” (id.), and “the
instant claims are defined by a composite comprising a biocompatible
polymer and a bioactive glass” (id.).
Nevertheless, we agree with Appellants that “[t]he term „reacted‟
represents a structural limitation” and “the claims must be construed as
involving a biocompatible polymer that is reacted with a bioreactive glass”
(App. Br. 12).
The Examiner has not established that Marcolongo meets this
requirement of the claims. Accordingly, the rejection of the claims as
anticipated by Marcolongo is reversed.
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SUMMARY
The rejection of claims 11, 13, 21-25, 28, 30, 34, 36, 37, 39, 41, 42,
and as anticipated by Ducheyne '990 is reversed.
The rejection of claims 11, 13, 21-29, 34-39, 41, 42, and 44 as
unpatentable over Ducheyne '990 and Ducheyne '453 is reversed.
The rejection of claims 11, 12, 14, 18-20, 30, and 33 as unpatentable
over Ducheyne '990 and Shikinami is reversed.
The rejection of claims 11-17, 28-32, 34-36, 38, 41, and 42 as
anticipated by Marcolongo is reversed.

REVERSED

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