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allowed to sit for 24 h at room temperature. The solvent
was removed by rotary evaporation, and the resultant
solid was dried under vacuum for 2–3 days. The product
obtained was used without further purification [mp 147.2–
155.1 °C; 13C NMR (DMSO-d6): d 175.7, 73.0, 72.6, 71.9,
71.0 and 63.9 ppm].
7. Hiratani, H.; Alvarez-Lorenzo, C. Biomaterials 2004, 25,
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13. Wolfrom, M. L.; Bennett, R. B.; Crum, J. D. J. Am. Chem.
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8. Oral, E.; Peppas, N. A. J. Biomed. Mat. Res., Part A 2006,
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14. For the batch binding studies, a 0.40:15 w/v ratio of the
dry polymer hydrogels to a 50 mg/ml solution of the
sugar analyte (i.e., D-glucose, L-glucose, D-gluconamide
or D-fructose) in deionized water (prepared from house
distilled water using a Corning MP-3A still) was used.
Typically the binding studies were performed on a scale of
50 mg of dried hydrogel in 1.875 mL of sugar solution.
The mixture was gently agitated for 4 h,9,10 and the
amount of sugar still in solution (and hence not bound to
hydrogel) was then immediately measured using 1H NMR
(recorded at 400 MHz on a JEOL GSX spectrometer). An
aliquot of the solution was removed (typically 0.5 mL)
and added to an equal volume of a standard acetic acid
solution in D2O [5:1000 (v/v) glacial acetic acid in D2O].
An 1H NMR spectrum was recorded and integrated
(though the final solution contained 50% H2O, the signals
for sugar and the acetic acid methyl group were well
resolved from the large water peak). The amount of sugar
still present in solution was determined by reference to a
calibration curve (see below), and the binding capacity of
the hydrogels (mg of sugar bound per gram of dry
hydrogel) then calculated. All binding studies were
performed in duplicate, and the average of the two
measurements was used to calculate the binding capaci-
ties. Calibration curves were constructed for D-glucose, L-
glucose, D-gluconamide, and D-fructose by employing
solutions of known concentration (25, 30, 35, 40, 45, and
50 mg/mL). As above, an aliquot of each of these
solutions (usually 0.5 mL) was added to the same volume
of the 5:1000 glacial acetic acid solution in D2O, and an
1H NMR spectrum recorded. The integration for signals
of the analyte compound and the acetic acid methyl
group was measured, and the ratio for the 25 mg/mL
solution of analyte normalized to 1.0. A calibration curve
was then constructed for each of the four analytes (n = 6;
R2 = 0.991 for D-fructose, 0.996 for D-gluconamide, 0.981
for D-glucose, and 0.994 for L-glucose).
9. Parmpi, P.; Kofinas, P. Biomaterials 2004, 25, 1969.
10. Wizeman, W. J.; Kofinas, P. Biomaterials 2001, 22, 1485.
11. In a typical procedure, a 25% w/v aqueous solution of
poly(allylamine hydrochloride) (average molecular weight
15,000) [1.0 g PAAÆHCl (10.7 mmol allylamineÆHCl mono-
mer) in 4.0 deionized water] was allowed to stir with
0.16 mol of the template (GPS-Ba, D-glucose, L-glucose,
BaHPO4, or D-gluconamide) for 2 h. 0.534 mL of a 10 M
NaOH solution (5.34 mmol) was then added and the
resultant solution was allowed to stir for 20 minutes,
followed by the addition of 0.109 mL of ( )-epichlorohy-
drin (1.39 mmol). As indicated by the numbers above, the
molar ratio of monomer/template/NaOH/crosslinker was
200:3:100:26, the values employed in the earlier reports.9,10
Upon addition of the EPI, gelation occurred in 10–15 min,
and the hydrogel was then allowed to sit undisturbed
overnight. The next day, the hydrogel was cut into
approximately 4 mm cubes with a razor blade and was
then washed with gentle shaking in 4 M NaOH solution
for 24 h to remove the template and any unreacted
reagents. The NaOH solution was decanted off the
hydrogel cubes, which were then repeatedly washed by
gently shaking in deionized water over a period of 5 days.
Each day, the hydrogels were washed 3–4 times for 1–2
hours, and after every wash the solution was decanted,
and the pH measured with pH paper. After the 5 day
period, overnight incubation of the hydrogels prepared
with D-glucose, L-glucose, and D-fructose, as well as the
one prepared in the absence of a template molecule,
yielded
a wash solution that was no longer basic
(pH ꢀ 6.5). However, even after the 5 days of washing,
the pH of the wash solution for the GPS-Ba and BaHPO4
hydrogels was still slightly basic (pH ꢀ 8). These hydrogels
were thus washed repeatedly for an additional 3–4 days,
but the pH did not drop further. All the polymers were
then dried, open to the air, for 18–24 h in an oven at 50 °C.
Between 0.6 and 0.7 g of washed and dried hydrogel was
routinely obtained. Assuming that all of epichlorohydrin
had fully reacted (with loss of HCl) with the polyallyl-
amine and that all salts and template had been fully
washed away, 0.69 g of dried hydrogel would correspond
to a 100% yield.
15. Ramstro¨m, O.; Yan, M. In Molecularly Imprinted Mate-
rials: Science and Technology; Yan, M., Ramstro¨m, O.,
Eds.; Marcel Dekker: New York, 2005; p 1.
16. Pitt, C. G.; Bao, Y. T.; Andrady, A. L.; Samuel, P. N. K.
Int. J. Pharm. 1988, 45, 1.
17. Data obtained from SciFinderÒ Scholar [calculated using
Advanced Chemistry Development (ACD/Labs) Software
V8.14 for Solaris, Ó 1994–2006 ACD/Labs].
12. D-Gluconamide was synthesized using the method of
Wolfrom et al.13 5.0 g of d-gluconolactone (28.0 mmol)
was dissolved in 18.3 mL of concentrated ammonium
hydroxide (28–30%, ꢁ0.3 mol), and the solution was
18. Sangster, J. J. Phys. Chem. Ref. Data 1989, 18, 1111.
´
19. Mazzobre, M. F.; Roman, M. V.; Mourelle, A. F.; Corti,
H. R. Carbohydr. Res. 2005, 340, 1207.