Living cells suspensed in a saline buffering media are exposed to microwave radiation without raising the temperature of the cells, to study the non-thermal effects of radiation on the cells, in an apparatus which includes a vertically disposed microwave waveguide having a partitioned end filled with a temperature controlled liquid solution. The sample is contained in a micropipette which projects across the width of the waveguide through the solution. The radiation projected through the waveguide and into the solution is measured.
Material having relatively high electrical resistivity, such as food products and containers, is disposed within a magnetic coil and subjected to one or more pulses of an oscillating magnetic field having an intensity of between about 2 and about 100 Tesla and a frequency of between about 5 and about 500 kHz. A single pulse of the magnetic field generally decreases the microorganism population by at least about two orders of magnitude, and substantially complete sterility is more closely approached by subjecting the material to additional pulses.
A flow-through cell cultivation apparatus and method is described. The flow-through cell cultivation system comprises a flowcell, a chamber inside the flowcell for holding cells, and a flowcell holder. The flowcell has a lower intake port for flowing liquid nutrient through a cellbed inside the flowcell and an upper outlet port for flowing the liquid nutrient out of the flowcell. The flowcell also includes a chuck for receipt of a thermal probe. The probe is made of electromagnetically non-interactive material. The flowcell is enclosed inside the flowcell holder. The flowcell holder includes a pair of intake ports into a cavity having an open end at the flowcell for turbulently flowing a temperature controlled gas against the flowcell. The cavity has rough walls to promote the turbulent flow. The flowcell holder includes an exhaust port for flowing the gas out of the flowcell holder which also serves as a port for another thermal probe. A one-way valve prevents flow of the liquid nutrient out of the chamber through the intake port. Temperature controlled air is supplied to the flowcell holder by dividing air from an air supply into two conduits. One conduit travels through a coil inside a refrigerated liquid bath and the other through a coil inside a heated liquid bath. The heated and cooled air are recombined to make an even temperature air supply which is then divided once more to provide the two air supplies for creating a turbulent supply of temperature controlled air through the two flowcell holder intake ports. The flowcell may include on one side a semi-permeable membrane for introducing a gas/liquid interface to the cellbed.
A flow-through cell cultivation apparatus and method is described. The flow-through cell cultivation system comprises a flowcell, a chamber inside the flowcell for holding cells, and a flowcell holder. The flowcell has a lower intake port for flowing liquid nutrient through a cellbed inside the flowcell and an upper outlet port for flowing the liquid nutrient out of the flowcell. The flowcell also includes a chuck for receipt of a thermal probe. The probe is made of electromagnetically non-interactive material. The flowcell is enclosed inside the flowcell holder. The flowcell holder includes a pair of intake ports into a cavity having an open end at the flowcell for turbulently flowing a temperature controlled gas against the flowcell. The cavity has rough walls to promote the turbulent flow. The flowcell holder includes an exhaust port for flowing the gas out of the flowcell holder which also serves as a port for another thermal probe. A one-way valve prevents flow of the liquid nutrient out of the chamber through the intake port. Temperature controlled air is supplied to the flowcell holder by dividing air from an air supply into two conduits. One conduit travels through a coil inside a refrigerated liquid bath and the other through a coil inside a heated liquid bath. The heated and cooled air are recombined to make an even temperature air supply which is then divided once more to provide the two air supplies for creating a turbulent supply of temperature controlled air through the two flowcell holder intake ports. The flowcell may include on one side a semi-permeable membrane for introducing a gas/liquid interface to the cellbed.
The present invention provides a method for detecting a molecular event, comprising (1) applying an electromagnetic test signal to a sample in which a molecular event is being detected, whereby the sample interacts with and modulates the test signal to produce a modulated test signal, and (2) detecting the modulated test signal, wherein the applying and detecting take place in a temperature-controlled environment, wherein the temperature-controlled environment comprises the sample, a radiating portion of a signal generating circuit, and a receiving portion of a signal detection circuit and wherein the applying and detecting take place in the environment at a temperature controlled to within .+-.0.5.degree. C.
A microwave device has a monolithic microwave integrated circuit (MMIC) disposed therein for applying microwave radiation to a microfluidic structure, such as a chamber, defined in the device. The microwave radiation from the MMIC is useful for heating samples introduced into the microfluidic structure and for effecting lysis of cells in the samples. Microfabrication techniques allow the fabrication of MMICs that perform heating and cell lysing of samples having volumes in the microliter to picoliter range.
