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CN-122006480-A - High-recovery-rate micro-filter and method

CN122006480ACN 122006480 ACN122006480 ACN 122006480ACN-122006480-A

Abstract

The application relates to the technical field of experimental equipment, and provides a high-recovery-rate micro-filter and a method thereof. The tapered channel of the conical tube body can guide samples to naturally converge under the action of centrifugal force, the dead volume of the cavity is greatly reduced, the filtering membrane component adopts the combination of the prefilter membrane and the fine filter membrane, the filtering precision is ensured, the blocking is prevented at the same time, and the key is that the pressure regulating interface arranged at the upper opening end allows the connection with an external pressure source after the centrifugation, the controllable positive pressure is applied to the top space, and the final liquid drop residue caused by the surface tension of the membrane is actively overcome. The bottom of the collecting pipe is provided with a collecting ridge which is convenient for collecting and sucking micro filtrate. The application can realize the recovery rate of more than 99 percent for 10-200 mu L of samples, and is particularly suitable for the pretreatment of precious and limited trace samples.

Inventors

  • ZHU XUDONG
  • YIN DONG

Assignees

  • 中山大学孙逸仙纪念医院

Dates

Publication Date
20260512
Application Date
20251231

Claims (10)

  1. 1. A micro-filter with high recovery rate, characterized by comprising the following steps: the conical tube body is provided with an upper opening end, a lower opening end and a tapered channel for connecting the upper opening end and the lower opening end; The filtering membrane component is fixedly arranged at the middle lower part of the tapered channel and divides the tapered channel into a top space at the upper part and an outflow channel at the lower part; a pressure regulating port provided at the upper opening end for sealing connection with an external pressure control device to selectively regulate the pressure in the head space, and A collection tube detachably and sealingly connected below the lower open end for receiving the filtered liquid; Wherein the tapered structure of the tapered channel, the location of the filtering membrane module, and the pressure regulating interface are collectively configured to enable a micro sample to pass through the filtering membrane module with high recovery rate under the drive of centrifugal force and/or controlled air pressure.
  2. 2. A high recovery micro filter according to claim 1, wherein the filter membrane module comprises at least two layers of filter membranes with successively decreasing pore sizes in the direction of liquid flow, wherein the nominal pore size of the downstream-most fine filter membrane is 0.22 μm and the nominal pore size of the upstream-most pre-filter membrane is between 0.45 μm and 10 μm.
  3. 3. The high recovery micro filter of claim 2, wherein the filter membrane module further comprises a porous support layer or a flow directing layer between the at least two filter membranes.
  4. 4. The high recovery micro filter of claim 1, wherein said pressure regulating interface comprises a valve structure capable of sealing said headspace in a closed condition and communicating said headspace with an external environment or pressure source in an open condition.
  5. 5. The high recovery micro filter of claim 1, wherein the taper angle of the tapered channel of the tapered tube body is between 5 ° and 30 °, and the filtering membrane module is disposed 1/4 to 1/2 of the total height of the tapered tube body from the lower open end.
  6. 6. A high recovery micro filter as claimed in claim 1, wherein the collection tube is centrally provided with an upwardly convex collection ridge or cone at the inner bottom for forming a pool of droplets upon collection of micro liquid.
  7. 7. The high recovery micro filter of claim 1, further comprising a detachable annular support, wherein the filtering membrane module is fixed in the annular support, and wherein the outer wall of the annular support is in interference fit with the inner wall of the tapered channel or forms a seal with a sealing ring.
  8. 8. The high recovery micro-filter of claim 1, wherein the conical tube body and the collection tube are detachably connected in a sealing manner by threads, luer-lock connectors or snap-fit structures.
  9. 9. The high recovery micro filter of claim 1, wherein in the initial storage state, the headspace and the pores of the filtration membrane module are filled with a storage liquid, the storage liquid being a non-volatile solvent having a viscosity greater than water or an aqueous solution composed of the same.
  10. 10. A method for performing micro-sample filtration, characterized in that it is carried out based on the high recovery micro-filter according to any one of claims 1-9, comprising the steps of: Providing the high-recovery micro-filter to ensure that the filtering membrane component of the micro-filter is wetted; a sample loading step, namely injecting a sample to be filtered with the volume smaller than 200 mu L into the top space of the conical tube body; a sealing step, namely, the pressure regulating interface is connected with a pressure control device in a sealing way; a step of driving filtration, in which the pressure of the head space is regulated through centrifugal operation and/or through the pressure control device, and a sample is driven to completely enter the collecting pipe through the filtering membrane component; and collecting, namely separating the collecting pipe to obtain filtrate.

Description

High-recovery-rate micro-filter and method Technical Field The invention belongs to the technical field of experimental equipment, and particularly relates to a high-recovery-rate micro-filter and a method. Background In the leading-edge scientific fields of biomedical research and development, clinical diagnosis, proteomics, metabonomics, nanomaterial analysis, etc., it is often necessary to process extremely precious or limited-volume liquid samples. The volume of these samples is typically between tens of microliters and two hundred microliters. When such micro-samples are filtered to remove particulate impurities, sediment, bacteria or cell debris, a long-standing technical pain is evident in that the recovery of the filtered sample is extremely low with conventional needle filters or small filter columns. The internal cavity of the traditional filter is cylindrical or has a large dead space, and the filtering membrane is generally arranged in the middle of the cavity. When the micro-sample is added, a portion of the liquid passes through the filter membrane under gravity or positive pressure drive, but a substantial portion of the liquid remains on the walls of the feed chamber, on the surface upstream of the membrane, and at the junction with the outlet structure. This fraction of the residual volume is very high relative to the total volume of the microsamples, resulting in a much smaller amount of filtrate being actually recovered than the loading. Experimental data indicate that recovery rates are typically only between 70% -85% for 50 μl of aqueous solution using conventional needle filters, and may be as low as 60% or less for very small amounts of 10 μl of sample. This unacceptable loss is fatal for samples of difficult sources, high cost, or extremely low concentrations. There have been some proposals in the prior art aimed at improving filtration efficiency or flux. For example, chinese patent CN213433865U discloses a needle filter with a multi-layer filter membrane structure, which aims to trap particles in stages, avoid excessively fast clogging of the membrane and increase the filtration amount by providing a four-layer structure of GFC membrane, GF10 membrane, PP membrane and microporous filter membrane. However, this design focuses on throughput and lifetime when handling relatively large volumes of samples, is not optimized for the cavity structure to minimize dead volume, nor does it take into account the special mechanical conditions required to drive trace amounts of liquid completely through the multilayer membrane, and therefore fails to address the core problem of low trace sample recovery. Therefore, there is an urgent need in the art for a new micro-filter design that is not simply a simple miniaturization of existing filters, but rather requires physical and conceptual redesign of its structure and operation to actively address dead volume residue and liquid film retention issues, thereby providing a reliable tool for micro-sample processing with recovery rates approaching 100%. Disclosure of Invention The invention aims to overcome the defects in the prior art and provide a high-recovery-rate micro-filter and a use method thereof. The invention is out of the design paradigm of the traditional filter, and by combining the unique conical convergence design and the pressure auxiliary drive, almost all micro samples are forcedly guided and pass through the filtering membrane, so that the unprecedented high recovery rate is realized. In order to achieve the above purpose, the present invention provides the following technical solutions: in a first aspect, the present invention provides a high recovery micro-filter comprising: the conical tube body is provided with an upper opening end, a lower opening end and a tapered channel for connecting the upper opening end and the lower opening end; The filtering membrane component is fixedly arranged at the middle lower part of the tapered channel and divides the tapered channel into a top space at the upper part and an outflow channel at the lower part; a pressure regulating port provided at the upper opening end for sealing connection with an external pressure control device to selectively regulate the pressure in the head space, and A collection tube detachably and sealingly connected below the lower open end for receiving the filtered liquid; Wherein the tapered structure of the tapered channel, the location of the filtering membrane module, and the pressure regulating interface are collectively configured to enable a micro sample to pass through the filtering membrane module with high recovery rate under the drive of centrifugal force and/or controlled air pressure. Further, the filtration membrane module comprises at least two layers of filtration membranes with pore diameters sequentially decreasing along the liquid flow direction, wherein the nominal pore diameter of the downstream-most fine filtration membrane is 0.22 μm, and the no