Chemistry: molecular biology and microbiology – Apparatus
Reexamination Certificate
1998-11-23
2001-11-06
Naff, David M. (Department: 1651)
Chemistry: molecular biology and microbiology
Apparatus
C435S178000, C435S182000, C435S382000, C436S529000, C436S535000, C530S813000, C530S817000
Reexamination Certificate
active
06312942
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention concerns a process and an apparatus for encapsulating microbial, vegetable and animal cells or biological and chemical substances through a nozzle into small, substantially spherical particles.
The encapsulation of microbial, vegetable and animal cells and biological and chemical substances such as catalysts is a matter of great significance in particular in biotechnology and medicine for immobilization purposes. In medicine encapsulation additionally serves to provide shielding from the immune system. By virtue of the immobilization effect, it is possible to retain the cells or the catalyst in the process and at the same time harvest the product. That makes it possible to achieve prolonged utility and an enhanced level of space-time yield. By virtue of the shielding effect for the cells from the immune system, it is possible to implant in a patient cells that are foreign to the patient's body and which over a prolonged period of time discharge a desired substance into the body of the patient without their being attacked and destroyed by the immune system of the patient.
The encapsulation of cells and catalysts in biopolymers such as carrageenan or alginate and synthetic polymers such as polyacrylamide is a method which has been used for some years in research laboratories. Many different apparatuses are described for that purpose in the literature. One of the most efficient methods involves dividing up a jet by the superimposition of an external oscillation or vibration on the immobilization fluid. That procedure provides that, as it is discharged from a nozzle in a laminar flow, the fluid is divided up into equal-sized fractions. A number of methods for vibration transmission are used or described, for example coupling to a vibrator, piezoelectric crystal, sound waves.
The applicants' WO 96/28247 shows a commercial encapsulation apparatus in which the vibration is transmitted by a rigid connection to a vibrator. That method suffers from the difficulty that the axis of the vibrator and the axis of the nozzle must be precisely aligned as otherwise disturbance phenomena occur, which have a massively adverse effect on the homogeneity of the sphere size. In addition the vibrator is expensive.
In consideration of that state of the art, the inventor set himself the aim of optimising an apparatus and a process of the kind set forth above.
SUMMARY OF THE INVENTION
In accordance with the process of the invention the immobilization mixture is divided into equal-sized fractions by the superimposition of an external vibration, wherein said vibrations are transmitted to the immobilization mixture either within a pulsation space or by way of the nozzle which is caused to pulsate.
The invention includes an apparatus in which a pulsation chamber which is arranged upstream of the nozzle and which accommodates the immobilization mixture is overlaid by a permanent magnet and the latter is arranged opposite an electric coil: one of the two units is provided in accordance with the invention within the pulsation chamber or on a diaphragm which spans over the pulsation chamber, while the other unit is separated from that associated with the pulsation chamber by an air gap.
In another embodiment of the apparatus, the permanent magnet and the electric coil are associated with the nozzle or the suspension means thereof so that it can introduce the pulsation effect.
In accordance with a further feature of the invention the permanent magnet and the coil through which alternating current flows generate vibrations in a preferred range of between 300 and 4000 Hz.
By virtue of the invention, using simple means, it is possible to miniaturize the vibration transmission means, with a very low level of expenditure in terms of material and energy. In that way the costs of the process and the apparatus can be reduced by a multiple in comparison with the previously known vibration processes.
The invention is essentially based on the fact that the principle of a vibrator comprising a magnet and a coil through which alternating current flows is taken out of the vibrator and a part thereof is associated directly with the pulsation chamber. If alternating current is passed through the coil, it is alternately positively and negatively magnetized. The magnetic waves interact with the magnet disposed therebeneath and cause it to vibrate. The vibrations are transmitted almost without resistance to the immobilization fluid.
A point which is to be deemed a further advantage is that alignment of the magnet and the coil does not have to be centered accurately to 0.1 mm. Also there are no axes which have to be exactly aligned.
REFERENCES:
patent: 5460943 (1995-10-01), Hayashi et al.
patent: 9628247 (1996-09-01), None
Brandenberger Harry
Heinzen Christoph
Plüss-Wenzinger Raphael
Widmer Fritz
Bachman & LaPointe P.C.
Inotech AG
Naff David M.
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