A micro-vial for handling micro-volume of sample fluids. The interior wall defined in the vial has a cylindrical sample section, a wider cylindrical alignment section, a tapered or conical guide section, and a relatively large cylindrical body section, arranged in sequence in that order along the center axis of the vial. The sample section holds a small volume of a sample fluid and receives the tip end of a capillary tube. The alignment section has a larger diameter than the sample section, receiving a cylindrical support that coaxially supports the relatively fragile capillary tube. The tip of the capillary tube dips into the micro-volume of sample fluid held in the sample section. The conical section guides the capillary tube and the support tube into the alignment section and the tip of the capillary tube into the sample section.

BACKGROUND OF THE INVENTION

1. Priority Claim

2. Field of the Invention

The present invention is directed to receptacles for holding fluid for bio-analysis, and more particularly to vials for holding small volumes of fluids.

3. Description of Related Art

DNA sequencing is a type of bio-analysis, involving the process of determining the precise order of nucleotides within a DNA molecule. It includes any method or technology that is used to determine the order of the four bases—adenine, guanine, cytosine, and thymine—in a strand of DNA. The advent of rapid DNA sequencing methods has greatly accelerated biological and medical research and discovery.

Knowledge of DNA sequences has become indispensable for basic biological research, and in numerous applied fields such as diagnostic, biotechnology, forensic biology, and biological systematics. The rapid speed of sequencing attained with modern DNA sequencing technology has been instrumental in the sequencing of complete DNA sequences, or genomes of numerous types and species of life, including the human genome and other complete DNA sequences of many animal, plant, and microbial species.

Next-generation sequencing (NGS) has revolutionized the genetic landscape. It is a lengthy, labor-intensive process that yields results never before achieved. As a result, it is imperative that the quality of the DNA sample be evaluated from the start, as most NGS sample preparation protocols require PCR amplification to generate DNA libraries prior to sequencing.

The likelihood of artifact generation could contribute to bias, affecting the potential results. High sensitivity DNA analysis has been optimized with the improved capillary gel electrophoresis detection systems developed by the assignee of the present invention, BiOptic, Inc. (see, U.S. Patent Application Publication Nos. US2011/0253540A1 and 2012/0168312A1; and, for example, the Qsep100 instrument developed by BiOptic, Inc.). Improved sensitivity allows the numbers of library PCR cycles to be reduced, removing amplification bias and significantly improving the quality of NGS data with increased accuracy.

Since relatively large volumes (e.g., in the order of 20 to 40 micro-liters) of PCR products are necessary/needed to be used in sequencing type instruments, and the sequencing sample preparation process is costly, preferably a small volume of PCR product is sampled for screening quickly (e.g., through gel-electrophoresis or capillary electrophoresis) to make sure there is enough PCR product present (detected) in the PCR products before proceeding with the full sequencing process (DNA analysis). This involves injecting a small volume of sample PCR product into the tip of a capillary tube, to allow the sample to undergo electrophoresis through the capillary tube. It is desired to sample as small a volume of PCR product as possible, so as to leave more PCR products available for subsequent sequencing.

It has always been a challenge in the field to try to contain a small volume of fluid in micro volume in the order of several micro-liters in a receptacle, and in particular in a manner to provide access to sample by a capillary tube.

SUMMARY OF THE INVENTION

The present invention provides a simple, low cost, efficient and stable micro-vial configuration for handling micro-volume of sample fluids, which overcomes the drawbacks of the prior art. Accordingly to the present invention, the internal wall geometry of the inventive vial is designed to include several axial sections of various interior diameters to provide a range of functionalities to address various design considerations. The interior wall defined in the vial has a cylindrical sample section, a wider cylindrical alignment section, a tapered or conical guide section, and a relatively large cylindrical body section, arranged in sequence in that order along the center axis of the vial.

The sample section has the smallest diameter of all the sections, designed to hold a small volume of a sample fluid (e.g., in the order of less than 5 micro-liters, preferably 1 to 2 micro liters), and to receive the tip end of a capillary tube. The alignment section has a larger diameter than the sample section, designed to receive a cylindrical support that coaxially supports the relatively fragile capillary tube. The support may be a metal tube, which extends from a capillary cartridge and functions as a tube-shaped electrode for such cartridge. The capillary tube is threaded through the bore of the support tube, and the tip of the capillary tube extends beyond and is exposed from the end of the support tube. The tip of the capillary tube dips into the micro-volume of sample fluid held in the sample section. The conical section functions to guide the capillary tube and the support tube into the alignment section and the tip of the capillary tube into the sample section. The body section has the largest diameter. The vial thus has the capacity to hold a relatively large volume of fluid, which can fill the body section.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This invention is described below in reference to various embodiments with reference to the figures. While this invention is described in terms of the best mode for achieving this invention's objectives, it will be appreciated by those skilled in the art that variations may be accomplished in view of these teachings without deviating from the spirit or scope of the invention.

The inventive micro-vial is described in connection with the embodiment of sample injection and detection technique in bio-analysis, particularly micro-volume sample injection, separation and detection through a micro-capillary channel, and more particularly a capillary tube supported in a gel capillary cartridge (e.g., developed by BiOptic, Inc.). The inventive micro-vial is especially useful for pre-screening of PCR DNA products prior to Next Generation Sequencing applications. The inventive micro-vial can be adapted for use with other bio-analysis tools, instruments and systems, in connection with other bio-analysis processes, which is well within the scope and spirit of the present invention.

The present invention provides a simple, low cost, efficient and stable micro-vial configuration for handling micro-volume of sample fluids, e.g., for injection into a capillary column for bio-separation (e.g., capillary electrophoresis for detection of PCR products (i.e., DNA sample)).

Referring to the embodiment shown inFIGS. 1-6, the micro volume vials10can be configured in a strip12of N vials (wherein N is at least 1, but can be 8, 12, or any desired number). Referring toFIGS. 7-12, an alternate embodiment is shown with broken lines to depict a strip12′ having at least two vials10, but the number of vials may be indefinite, or of any number. Further, instead of a strip of a plurality of vials10, it is well within the present invention to configure separate single vials10(see, e.g.,FIG. 15, depicting a single vial10). Further, instead of strips, the vials10may be defined as wells in a block or plate (i.e., a 96-well micro-titer plate having wells defined with the interior wall geometry of the vial10disclosed here).

Specifically, adjacent vials are connected at the opening area by a tap14. A handle19is provided at each end of the strip12. In one embodiment, the center spacing between vials may be configured to correspond to the format of an industry standard 96-well (8×12) micro-titer plate. Several strips12of vials may be assembled to form a tray of wells, e.g., resembling a 96-well titer plate, by using an appropriate holder or bracket (not shown).

Referring to the sectional views inFIGS. 6 and 12, the vial10has an external geometry which is not critical to the function of micro-volume fluid handling. In this regards, the vial10may be configured with a relatively large external body (e.g., a block having interior walls defining the interior wall geometry of the vial) for easier handling by a user. Accordingly to the present invention, the internal wall geometry of each vial10is designed to include several axial sections of various interior diameters to provide a range of functionalities to address various design considerations. Referring also to the pictorialFIG. 15, the interior wall defined in the vial10has a cylindrical sample section20, a cylindrical alignment section22, a tapered or conical section24, and a cylindrical body section26, arranged in sequence in that order along the center axis18of the vial. As shown in this embodiment, the wider cylindrical alignment section22is immediate adjoining to the cylindrical sample section20along the center axis of the body, wherein an exit end of the wider cylindrical alignment section22immediate adjoins an opening end of the cylindrical sample section20.

The section20has a cylindrical section with a bottom, and has the smallest diameter of all the sections, designed to hold a small volume of a sample fluid30(e.g., in the order of less than 5 micro-liters, preferably 1 to 2 micro liters), and to receive the tip end of a capillary tube32(e.g., about 0.350-400 mm overall external diameter, including cladding or protective coating on the silica capillary tube32).

The alignment section22has a larger diameter than section20, designed to receive a cylindrical support34that coaxially supports the relatively fragile capillary tube32. The support may be a metal tube (e.g., about 1 mm outside diameter, with a bore having an inner diameter of about 0.5 mm internal diameter to receive the capillary tube32), which extends from a capillary cartridge38and functions as a tube-shaped cathode34for such cartridge28, as shown inFIG. 15(see BiOptic's capillary cartridge and analysis system discussed in U.S. Patent Application Publication Nos. US2011/0253540A1 and 2012/0168312A1). The capillary tube32is threaded through the support tube34, and the tip of the capillary tube32extends beyond and is exposed from the end of the support tube34. As shown inFIG. 15, the tip of the capillary tube32dips into the sample fluid in section20.

The conical section24provides a tapered wall surface to guide the capillary tube32and the support tube34into the alignment section22and the tip of the capillary tube32into the section20.

The body section26has an opening, and the largest diameter of the wall sections. The vial10thus has the capacity to hold a relatively large volume of fluid, which can fill the body section26.

A mineral oil36may be provided to fill the space above the sample fluid in the section20, to prevent evaporation of the small volume of sample fluid. The mineral oil36may fill the alignment section22and/or the conical section24and/or the body section26.

Referring toFIGS. 16-19, exemplary dimensions of a strip12of vials10are provided, in accordance with one embodiment of the present invention. All dimensions shown inFIGS. 16-19are in mm unit, unless otherwise stated.

The above described micro-vials10and strips12may be made of materials including glass, metal, plastic, rubber, silicon, etc., preferably of a chemically inert material that is inert to reacting with the fluid intended to be held in the vials10. The vials10and/or strips12may be formed by etching (e.g., of a semiconductor material such as a silicon substrate), stamping (e.g., of a metal or plastic), or molding (e.g., plastic or rubber injection molding). Further, the vials10and strip12may be made of different materials, which may be fused together to form the strip12. The wall structure of the vials may be made of a certain material and the interior wall of the vials10may be lined with a chemically inert material.

Using the inventive vial for handling a micro volume of sample fluid, it is possible to develop bio-analysis systems that are significantly small in overall size (see, e.g., BiOptic's Qsep 100 instrument). Miniaturization of analytical instrumentation has many advantages over conventional systems and techniques. These advantages include improved data precision and reproducibility, short analysis times, minimal sample consumption, improved automation and integration of complex workflows.

In one embodiment, an injection-molded vial10can accommodate a small volume of 1 to 2 micro-liters (e.g., of PCR DNA Sample to be injected electro-kinetically using Capillary Gel Electrophoresis (CGE) for pre-screening and quality control (qualitative and quantitative). The micro-vials are injection molded in strips of 8-vials or 12-vials and can be directly inserted inside the BiOptic's CGE system (Qsep100) Sample Tray to interface the Pen-Shaped Gel-Cartridge for sample intake through the automated sample tray. Reference is made to BiOptic's capillary cartridge and analysis system discussed in U.S. Patent Application Publication Nos. US2011/0253540A1 and 2012/0168312A1).

According to the micro-vial design geometry of the present invention, it facilitates sample injection in micro-liter volume of 1 to 2 micro-liters. The alignment section22of the vial10allows the gel-cartridge electrode (cathode tube34inFIG. 15) with supported capillary tube32to be inserted and aligned accurately for sample intake at the sample holding section20.

The access of sample held in the vial10by a cartridge38is schematically shown inFIGS. 13, 14 and 15. Referring to BiOptic's Qsep100 DNA analyzer, the cartridge38is supported on a stand50(schematically shown inFIG. 13), and a robotic mechanism52(schematically shown inFIG. 13) moves the sample tray supporting the vials10relative to the tip of the capillary tube32supported in the cartridge38. The cathode tube34(which coaxially supports the capillary tube32) in the cartridge38may be aligned automatically by the sample tray mechanism, with the conical tapered section24of the vial10guiding entry of cathode tube34inside the alignment section22, which has an internal diameter (e.g., 1.75 mm) that is close to the outside diameter of the cathode tube34(1 mm). Referring toFIGS. 14 and 15, as the cathode tube34is further inserted inside the vial10, the tip of the capillary tube32is guided and aligned to ensure contact with the test or sample solution30(e.g., DNA sample).

One micro-liter of test solution can be placed in the sample section20inside the vial10by using, for example, a standard handheld pipette. Since small air-bubbles could be introduced during sample deposition by the pipette, it is recommended to spin (centrifuge) the vial10(e.g., the entire strips12before further processing (in much the same way a standard 96-well microtiter plate is centrifuged). It is also recommended to apply a small amount of mineral oil to prevent sample evaporation and facilitate multiple consecutive sample injections.

The vials10are designed to be single unit, or in 8 and/or 12-strips, or could be molded to be 96-vial or 384-vial format. The vials10can be used with other capillary electrophoresis, HPLC or micro-fluidic type products (from different manufacturers) that have capillary based cartridge, in which the capillary is supported by a metal, plastic, ceramic or other outside jacket/electrode.

In Summary, the inventive micro-vial achieve one or more of the following advantages:

The inventive micro-vial allows handling of 1 to 2 micro-liter volume of sample (e.g., PCR DNA sample) to be allocated inside the vial to be interfaced with a capillary based cartridge for automated sample injection.

By applying a drop of mineral oil over the 1 to 2 micro-liters of sample inside the micro-vial, one can do multiple sample injections (electro-kinetically) into the pen-shaped gel-cartridge. The mineral oil prevents sample evaporation, and due to conductive properties, it also facilitates multiple injections.

The inventive strips of vials (e.g., injection molded strips) may be either in a strips of 8 or 12 vials, conforming to industry standard formats, which allows the strips to be expanded to 96-vial and/or 384-vial formats, if desired.

The inventive micro-vial design allows small consumption of DNA products (gDNA) to be sample for quality control prior to qPCR or Sanger Sequencing analysis, or for post-PCR sample analysis using capillary electrophoresis-based DNA fragment analyzers.

The inventive micro-vial design provides flexibility for automated sample injection in CGE based instruments.

The inventive micro-vial design provides robust and reproducible sample injections, resulting in accurate analysis results with better integrity.

While the invention has been particularly shown and described with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit, scope, and teaching of the invention. Accordingly, the disclosed invention is to be considered merely as illustrative and limited in scope only as specified in the appended claims.