addressing the challenge. These combined units are often named MGPs
(macroporous gel particles).
MIPs were synthesized with 17β-estradiol as template in the presence of some
acrylic monomers and crosslinkers. The polymerization gave a block polymer that
was mechanically disrupted; the particles were sieved and two fractions were saved,
25–38 μm and 38–106 μm. The MIPs were extensively washed with methanol in
order to remove the print molecule. After drying, the smaller fraction was added to
the monomer solution that was going to be polymerized to a cryogel. The polymerization took place in a glass tube filled with plastic housings of AnoxKaldnes
type. After polymerization, the housings with their content (the MGPs) were
separated from surplus cryogel and then washed properly before use. More details
can be found in the literature [110–112].
The MGPs were placed in a fluidized bed through which the water to be treated
was passed. Fluidization was used in order to get some mixing in the bed. A
schematic presentation of the set-up is shown in Fig. 16 [112]. When running
buffer solutions spiked with estradiol, it was shown that 100 % (within the experimental error) was removed. No estrogen could be detected afterwards. Estradiol is
very hydrophobic, and therefore hydrophobic monomers had been used to create
the cryogel. Whereas the MIPs gave efficient removal of all estradiol from the water
0
300
600
900
-3
-4
-5
-3
-4
-5
-6
-7
-8
-9
Estradiol Concentration Log (M) →
Blank
MIP
NIP
β-galactosidase activity
Extracts
Fig. 17 β-galactosidase activity in transformed Saccharomyces cerevisiae cultures exposed to
estradiol concentrations of 1 Â 10
À3 to 1 Â 10
À9 M in methanol/acetic acid (4:1 v/v) (MeOH:Aa)
(symbols) compared to clean MeOH:Aa (bar, Blank) or extracts from solid-phase extraction (SPE)
columns packed with 100 mg MIP or NIP and percolated with 100 mL of a wastewater sample (bars,
MIP and NIP, respectively). The results from the different adsorbents are presented as bars in the figure.
The polymers were extracted with 4 mL of MeOH:Aa and the values shown represent the average yeast
activity (normalized to 100 mL of wastewater) Æ standard deviation. No activity was found in the
extracts (4 mL MeOH:Aa) from SPE columns packed with clean MIP and NIP (100 mg). β-Galactosidase activity is calculated as 1000  OD 420 /(t  V  OD 660 ), where OD 420 is the final absorbance
at 420 nm, t is the time of reaction of the mixture (41 min), V is the volume of culture used in the assay,
and OD 660 is the absorbance of the diluted yeast inoculum. (Reproduced from [111] with permission)
Cryogels for Biotechnological Applications
273
(macroporous gel particles).
MIPs were synthesized with 17β-estradiol as template in the presence of some
acrylic monomers and crosslinkers. The polymerization gave a block polymer that
was mechanically disrupted; the particles were sieved and two fractions were saved,
25–38 μm and 38–106 μm. The MIPs were extensively washed with methanol in
order to remove the print molecule. After drying, the smaller fraction was added to
the monomer solution that was going to be polymerized to a cryogel. The polymerization took place in a glass tube filled with plastic housings of AnoxKaldnes
type. After polymerization, the housings with their content (the MGPs) were
separated from surplus cryogel and then washed properly before use. More details
can be found in the literature [110–112].
The MGPs were placed in a fluidized bed through which the water to be treated
was passed. Fluidization was used in order to get some mixing in the bed. A
schematic presentation of the set-up is shown in Fig. 16 [112]. When running
buffer solutions spiked with estradiol, it was shown that 100 % (within the experimental error) was removed. No estrogen could be detected afterwards. Estradiol is
very hydrophobic, and therefore hydrophobic monomers had been used to create
the cryogel. Whereas the MIPs gave efficient removal of all estradiol from the water
0
300
600
900
-3
-4
-5
-3
-4
-5
-6
-7
-8
-9
Estradiol Concentration Log (M) →
Blank
MIP
NIP
β-galactosidase activity
Extracts
Fig. 17 β-galactosidase activity in transformed Saccharomyces cerevisiae cultures exposed to
estradiol concentrations of 1 Â 10
À3 to 1 Â 10
À9 M in methanol/acetic acid (4:1 v/v) (MeOH:Aa)
(symbols) compared to clean MeOH:Aa (bar, Blank) or extracts from solid-phase extraction (SPE)
columns packed with 100 mg MIP or NIP and percolated with 100 mL of a wastewater sample (bars,
MIP and NIP, respectively). The results from the different adsorbents are presented as bars in the figure.
The polymers were extracted with 4 mL of MeOH:Aa and the values shown represent the average yeast
activity (normalized to 100 mL of wastewater) Æ standard deviation. No activity was found in the
extracts (4 mL MeOH:Aa) from SPE columns packed with clean MIP and NIP (100 mg). β-Galactosidase activity is calculated as 1000  OD 420 /(t  V  OD 660 ), where OD 420 is the final absorbance
at 420 nm, t is the time of reaction of the mixture (41 min), V is the volume of culture used in the assay,
and OD 660 is the absorbance of the diluted yeast inoculum. (Reproduced from [111] with permission)
Cryogels for Biotechnological Applications
273