摘要:
Improved detection methods and apparatus which may be used individually or in various combinations enhance the ability of the electrophoresis apparatus to detect fluorophore-labeled materials in short periods of time. One such apparatus comprises a housing adapted to receive an electrophoresis gel holder; an excitation source of electromagnetic radiation having a frequency effective to induce emission of electromagnetic radiation from the fluorophore; a plurality of optical fibers for delivering electromagnetic radiation from the excitation source to a linear array of excitation/detection sites on the gel holder, optical switching means for sequentially directing electromagnetic radiation into one of several pre-defined groups of the optical fibers; detection means such as a photomultiplier tube, or an array of photomultiplier tubes for detecting emission from the fluorophore induced by a radiation from the excitation source; and means for correlating a detected emission with the switching of the excitation electromagnetic radiation such that a given emission may be linked with the excitation/detection site being irradiated.
摘要:
An electrophoresis microgel is formed in a gel holder. The gel holder comprises a top substrate, a bottom substrate and a spacer disposed between the top substrate and the bottom substrate. The spacer establishes a separation of from 25 to 250 microns between the top substrate and the bottom substrate. A gel compartment is formed by partially sealing the top substrate to the bottom substrate, while leaving an opening for the introduction of unpolymerized gel. The gel compartment is then filled with an unpolymerized gel, which is polymerized in the gel compartment. Electrodes may be printed on the substrates, may be contacts to an exposed edge of gel, or may be applied through windows cut into one of the substrates. One type of gel holder makes use of graded beads having a diameter of 25 to 250 microns slurried in an adhesive such as an acrylate adhesive as the spacer. The slurry is printed onto the surface of one or both substrates to form a spacer of the desired shape, and then hardened using heat or light. If desired, the spacer can establish lanes within the gel.
摘要:
Improved detection methods and apparatus which may be used individually or in combinations enhance the ability of the electrophoresis apparatus to detect fluorophore-labeled materials in short periods of time. One such apparatus comprises a housing adapted to receive an electrophoresis gel holder; an excitation source of electromagnetic radiation having a frequency effective to induce emission of electromagnetic radiation from the fluorophore; a plurality of optical fibers for delivering electromagnetic radiation from the excitation source to a linear array of excitation/detection sites on the gel holder, optical switching means for sequentially directing electromagnetic radiation into one of several pre-defined groups of the optical fibers; detection means such as a photomultiplier tube, or an array of photomultiplier tubes for detecting emission from the fluorophore induced by a radiation from the excitation source; and means for correlating a detected emission with the switching of the excitation electromagnetic radiation such that a given emission may be linked with the excitation/detection site being irradiated. For example, the optical switching means may alternate between directing radiation from the source into every other optical fiber, or may provide radiation in rotation to every third or fourth fiber. Alternatively, a spot array generation grating can be used for dividing an incident beam of coherent radiation into an array of excitation beamlets and directing each excitation beamlets to an excitation/detection site on the electrophoresis gel. Light emitting diode disposed to deliver excitation energy to an array of excitation/detection sites may also be used. This latter form of the apparatus is particularly advantageous due to the low costs of light emitting diodes (LEDs) compared to coherent light sources (e.g. lasers).
摘要:
An electrophoresis microgel is formed in a gel holder. The gel holder comprises a top substrate, a bottom substrate and a spacer disposed between the top substrate and the bottom substrate. The spacer establishes a separation of from 25 to 250 microns between the top substrate and the bottom substrate. A gel compartment is formed by partially sealing the top substrate to the bottom substrate, while leaving an opening for the introduction of unpolymerized gel. The gel compartment is then filled with an unpolymerized gel, which is polymerized in the gel compartment. Electrodes may be printed on the substrates, may be contacts to an exposed edge of gel, or may be applied through windows cut into one of the substrates. One type of gel holder makes use of graded beads having a diameter of 25 to 250 microns slurried in an adhesive such as an acrylate adhesive as the spacer. The slurry is printed onto the surface of one or both substrates to form a spacer of the desired shape, and then hardened using heat or light. If desired, the spacer can establish lanes within the gel.
摘要:
An apparatus for the rapid preparation of electrophoresis gels comprises: (a) a housing; (b) a support fixture removably disposed within the housing and adapted to receive a gel holder having an internal gel compartment, the support fixture being optionally adapted to permit filling of the gel holder within the housing; (c) an optional injection system, which is connectible to a reservoir for holding a polymerizable solution; (d) an optional solution injection connector adapted to couple the injection system to a gel holder placed within the filling fixture, (e) an optional controller for the injection system, which causes the injection system to inject polymerizable solution from the reservoir into the gel compartment; and (f) a radiation source disposed within the housing in a location effective to irradiate polymierizable solution within the gel compartment of a gel holder in the support fixture. The support fixture may be mounted on a drawer which is slidable between a position inside the housing, and a position outside the housing to permit easy placement of a gel holder into the support fixture.
摘要:
A high dynamic range apparatus for separation and detection of polynucleotide fragments has a housing adapted to receive an electrophoresis gel holder containing an electrophoresis gel loaded with fluorophore-labeled samples; one or more laser diodes for providing radiation of a frequency suitable for excitation of the fluorophore which irradiates a an array of excitation/detection sites on the electrophoresis gel; an array of detectors aligned with the excitation/detection sites for collecting fluorescent emissions; and one or more components for increasing the dynamic range of the instrument by at least an order of magnitude. These components, which can be used individually or in combination include detectors that are connected to a signal processing system that modulates the period of signal integration employed so that large signals are totaled at short time intervals and smaller signals are totaled at longer time intervals; the use of a beam splitter to produces a high intensity beam of emitted light and a low intensity beam of emitted light from each excitation/detection site; and a device for modulating the intensity of the excitation beam can be used to improve the dynamic range of the instrument.
摘要:
An improved electrophoresis and fluorescence detection apparatus has an electromagnetic radiation sensor juxtaposed with a sensing region. The output signal from the electromagnetic radiation sensor is a current signal, and the current signal is converted to a voltage signal. The voltage signal is summed with a programmable offset generated by an inexpensive eight-bit D/A converter. The offset signal is selected to establish a lower starting point for the dynamic range of the A/D conversion, and is selected to null some or all of the background electromagnetic radiation level. The summed signal is amplified and integrated in an integrator. The integrator is switchable under program control. The integrator is switched on for long and short intervals. The short intervals permit sensing over a dynamic range accommodating very high levels of fluorescence; very high peaks may be measured and features of the peaks distinguished. The long intervals permit sensing over a dynamic range that is optimized for the peaks associated with the smaller peaks of individual nucleotides. In this way, the dynamic range of the A/D convertor is set to permit the highest possible resolution over the range of interest during the time in which the sequencing of the nucleotides takes place. The sequencer is fast and economical and yields data with high resolution.
摘要:
Electrophoresis gels are formed using a gel-forming insert having a beveled edge which results in loading sites having a beveled bottom surface. The gel forming insert can have a continuous beveled edge across the entire width of the gel, in which case a special loading insert is used which matches the bevel of the gel. Alternatively, the gel forming insert may be formed with a plurality of fingers with beveled ends, each finger defining a well in the gel. In one form of the gel-forming insert, the fingers are formed from a soft, flexible polymer such as silicone applied on a rigid support.
摘要:
An improved electrophoresis and fluorescence detection method for nucleotide sequences comprises a fluorescence sensing region along the path of nucleotide detection, coupled with amplification and integration in an integrator of output signals in the form of activity peaks. The output signal, which is converted to a voltage signal, is summed with a programmable offset generated by an inexpensive eight-bit D/A converter. The offset signal is selected to establish a lower starting point for the dynamic range of analog-digital conversion, and is selected to null some or all of the background fluorescence level. The integrator is switchable under program control. The integrator is switched on for long and short integration intervals. The short intervals permit sensing over a dynamic range accommodating very high levels of fluorescence; very high peaks may be measured and features of the peaks distinguished. The long intervals permit sensing over a dynamic range that is optimized for the peaks associated with the smaller peaks of individual nucleotides. In this way, the dynamic range of the analog-digital conversion permits the highest possible resolution over the range of interest during the time in which the sequencing of the nucleotides takes place. The method of nucleotide sequencing and analysis is fast, economical, and yields data with high resolution.
摘要:
An apparatus for the rapid filling and polymerization of electrophoresis gels comprises:(a) a housing;(b) a filling fixture removably disposed within the housing and adapted to receive a gel holder having an internal gel compartment;(c) an injection system, which is connectible to a reservoir for holding a polymerizable solution;(d) a solution injection connector adapted to couple the injection system to a gel holder placed within the filling fixture,(e) a controller for the injection system, which causes the injection system to inject polymerizable solution from the reservoir into the gel compartment; and(f) a radiation source disposed within the housing in a location effective to irradiate polymerizable solution within the gel compartment of a gel holder in the filling fixture. The filling fixture may be mounted on a base which is slidable between a position inside the housing, and a position outside the housing to permit easy placement of a gel holder into the filling fixture.