Method for reducing non-specific aggregation of latex microparticles in the presence of serum or plasma
AssigneeBeckman Coulter, Inc.
InventorsKurt L. Brillhart, Julie A. Whiteside
Life of this patent
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Abstract
A particle-enhanced assay for determining an analyte in a test sample in which an additive for reducing non-specific particle aggregation is added in an amount to substantially reduce non-specific aggregation.
Claims36
An assay for detecting the presence of an analyte of interest in a test sample, comprising:
- (a) forming a reaction mixture by combining:
- (i) said test sample;
- (ii) a known amount of sensitized particles having immobilized thereon an analyte-specific binding partner;
- and
- (iii) a known amount of an additive that reduces non-specific aggregation of said particles, wherein said additive is a compound having the formula:
- 6
- where
- R1 and R2 independently are substituted or unsubstituted alkyl or —(CH2)mOH;
- m is 1-3;
- R3 is hydroxy, cyano, substituted or unsubstituted alkyl, —COOX, or —CH(NH2)Y;
- X is hydrogen or substituted or unsubstituted alkyl;
- Y is hydrogen, substituted or unsubstituted amino, or substituted or unsubstituted alkyl;
- and
- n is 0-3;
- (b) incubating the reaction mixture under conditions that allow said particle-immobilized binding partner to bind to said analyte to cause specific aggregation of said particles, wherein said additive is present in an amount sufficient to reduce non-specific particle aggregation;
- and
- (c) determining the extent of specific aggregation, wherein the extent is proportional to the amount of said analyte in said sample.
An indirect assay for determining the presence of an analyte of interest in a test sample, comprising:
- (a) providing a sample which may contain the analyte of interest;
- (b) providing a known amount of a suspension of sensitized particles having analyte of interest immobilized thereon;
- (c) providing a known amount of an analyte-specific binding partner;
- providing an additive that reduces non-specific aggregation of said particles, wherein said additive is a compound having the formula:
- 7
- where
- R1 and R2 independently are substituted or unsubstituted alkyl or —(CH2)mOH;
- m is 1-3;
- R3 is hydroxy, cyano, substituted or unsubstituted alkyl, —COOX, or —CH(NH2)Y;
- X is hydrogen or substituted or unsubstituted alkyl;
- Y is hydrogen, substituted or unsubstituted amino, or substituted or unsubstituted alkyl;
- and
- n is 0-3;
- (d) combining said sample with said sensitized particles, said binding partner and said additive under conditions that allow binding between said binding partner and said particle-immobilized analyte to cause specific aggregation of said particles or to said analyte in said sample, wherein said additive is present in an amount sufficient to reduce non-specific particle aggregation;
- and
- (e) determining the amount of said particle-immobilized analyte that is bound with said binding partner, wherein the amount is inversely proportional to the amount of said analyte in said sample.
A kit for assaying an analyte in a test sample, said kit comprising first and second container means, said first container means containing sensitized particles having an analyte-specific binding partner immobilized thereon, said second container means containing a sufficient amount of an additive to reduce non-specific aggregation of said particles, wherein said additive is a compound having the formula:
- 8
- where
- R1 and R2 independently are substituted or unsubstituted alkyl or —(CH2)mOH;
- m is 1-3;
- R3 is hydroxy, cyano, substituted or unsubstituted alkyl, —COOX, or —CH(NH2)Y;
- X is hydrogen or substituted or unsubstituted alkyl;
- Y is hydrogen, substituted or unsubstituted amino, or substituted or unsubstituted alkyl;
- and
- n is 0-3.
A composition useful for assaying an analyte of interest, said composition comprising microparticles having an analyte-specific binding partner immobilized thereon, and a sufficient amount of an additive to reduce non-specific aggregation of said particles, wherein said additive is a compound having the formula:
- 9
- where
- R1 and R2 independently are substituted or unsubstituted alkyl or —(CH2)mOH;
- m is 1-3;
- R3 is hydroxy, cyano, substituted or unsubstituted alkyl, —COOX, or —CH(NH2)Y;
- X is hydrogen or substituted or unsubstituted alkyl;
- Y is hydrogen, substituted or unsubstituted amino, or substituted or unsubstituted alkyl;
- and
- n is 0-3.
Dependencies are inferred from the claim text.