Urease Encapsulation in Nanoorganized Microshells

Decher G., 1997, Science, 227, 1232, 10.1126/science.277.5330.1232

Sukhorukov G., 1998, Polym. Adv. Technol, 9, 759, 10.1002/(SICI)1099-1581(1998100)9:10/11<759::AID-PAT846>3.0.CO;2-Q

Sukhorukov G., 1998, Colloids Surfaces A, 137, 253, 10.1016/S0927-7757(98)00213-1

Donath E., 1998, Angew. Chem, Int. Ed. Engl., 37, 2202, 10.1002/(SICI)1521-3773(19980904)37:16<2201::AID-ANIE2201>3.0.CO;2-E

Caruso F., 1998, Science, 282, 1111, 10.1126/science.282.5391.1111

Caruso F., 2000, Langmuir, 16, 9595, 10.1021/la000942h

Lvov Y., 2000, Langmuir, 16, 5932, 10.1021/la000069k

Voigt A., 1999, Ind. Eng. Chem. Res., 38, 4037, 10.1021/ie9900925

Sukhorukov G., 2000, J. Microencapsulation, 17, 177, 10.1080/026520400288418

Moya S., 2000, Macromolecules, 33, 4538, 10.1021/ma9914974

Radtchenko I., 2000, J. Colloid Interface Sci., 230, 272, 10.1006/jcis.2000.7068

Sukhorukov G., 2001, Macromol. Rapid Commun., 22, 44, 10.1002/1521-3927(20010101)22:1<44::AID-MARC44>3.0.CO;2-U

Antipov A., 2001, J. Phys. Chem., 105, 723, 10.1021/jp002184+

Mendelson J., 2000, Langmuir, 16, 5017, 10.1021/la000075g

Moynihan H., 1989, Biotechnol. Bioengineer., 34, 34951, 10.1002/bit.260340710

Vasudevan P., 1990, Biotechnol. Bioengineer., 35, 1145, 10.1002/bit.260351110

Schussel L., 1995, Chemosphere, 30, 985, 10.1016/0045-6535(94)00453-2

Paddeu S., 1995, Sens. Actuators, 25, 876, 10.1016/0925-4005(95)85193-3

Chandler H., 1982, J. Immunolog. Methods, 53, 187, 10.1016/0022-1759(82)90140-5

Jabri E., 1992, J. Mol. Biol., 227, 934, 10.1016/0022-2836(92)90232-9

Lvov, Y.; Caruso, F.Anal. Chem.2001, in press.

Confocal laser scanning microscopy. Confocal micrographs were taken with Leica TCS SP, equipped with a 100× oil immersion objective. The investigated capsule suspension was placed between glass slide and cover slip glued at the edges. Excitation wavelength 488 nm was chosen accordingly to fluorescein labels.

To control the weight of empty and loaded capsules, the quartz crystal microbalance technique (QCM, USI-System, Japan) was used.27In the measurements, 5 μL of empty shells or loaded capsules with equal particle concentrations were dropped onto the QCM electrode and dried. By frequency shift, we calculated the mass of capsules in the solutions. The long-term stability (several hours) of the quartz resonator frequency was within ±2 Hz. The resonators used were coated with evaporated gold electrodes (0.16 cm2) on both faces, and their resonance frequency was 9 MHz (AT-cut). For the QCM electrodes used in this work, the following relationships between the frequency shift (ΔF, Hz) and polyion layer mass (M, g) is valid: M= −0.87 × 10-9·ΔF.27-28

Onda M., 1999, J. Ferment. Bioengin., 87, 69

Lvov Y., 1995, J. Am. Chem. Soc., 117, 6117, 10.1021/ja00127a026

Sauerbrey G., 1959, Z. Physik, 155, 206, 10.1007/BF01337937