# US 5,707,877 A · Biodegradable gelatin-aminodextran particle coatings of and processes for making same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,707,877 A - Document ID: US5707877A - Status: Granted - Kind: A - Application number: 08/493,973 - Filed: 1995-06-23 - Granted: 1998-01-13 - Earliest claimed: 1990-10-31 - Assignees: Coulter Corporation - Inventors: Olavi Siiman; Alexander Burshteyn; Ravinder K. Gupta - Web page: https://patentgrep.com/patent/US5707877A ## CPC - B03C 1/01: by addition of magnetic adjuvants - G01N 33/531: Production of immunochemical test materials - G01N 33/54313: {the carrier being characterised by its particulate form} - G01N 33/5434: {using magnetic particle immunoreagent carriers which constitute new materials per se} - G01N 33/54393: {Improving reaction conditions or stability, e.g. by coating or irradiation of surface, by reduction of non-specific binding, by promotion of specific binding} - G01N 2446/20: the magnetic material being present in the particle core - G01N 2446/30: the magnetic material being dispersed in the polymer composition before their conversion into particulate form - G01N 2446/84: Polymer coating, e.g. gelatin - G01N 2446/86: the coating being pre-functionalised for attaching immunoreagents, e.g. aminodextran - G01N 2446/90: characterised by small molecule linker used to couple immunoreagents to magnetic particles - Y10S 530/81: Carrier - bound or immobilized peptides or proteins and the preparation thereof, e.g. biological cell or cell fragment as carrier - Y10S 530/812: Peptides or proteins is immobilized on, or in, an organic carrier - Y10S 530/813: Carrier is a saccharide - Y10T 428/2991: Coated - B03C: MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS (separating isotopes B01D59/00; combinations of magnetic or electrostatic separation with separation of solids by other means B03B, B07B) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The invention relates generally to colloidal particle having a core material and a gelatin/aminodextran coating with pendent functional groups attached thereto. Biological substances or molecules, especially monoclonal antibodies, may be attached to said particles. The monoclonal antibody containing particles are useful in a variety of positive and negative biological assays. ## Claims ### Claim 1 A method of preparing aminodextran compounds in aqueous solution comprising: (a) partially oxidizing a dextran compound to dextran aldehyde using a chemical oxidizing agent such as sodium periodate at ambient room temperature; (b) desalting the dextran-aldehyde solution of step (a); (c) reacting the dextran-aldehyde of step (b) with a diamine at a temperature of about 5-10.degree. C. to form a plurality of Schiff's base linkages between the dextran-aldehyde and amino groups of the diamine; and (d) reducing the Schiff's base linkages of step (c) to obtain an amino-dextran through the use of a chemical reducing agent. ### Claim 2 (depends on 1) The method of claim 1 wherein said dextran has a molecular weight in the range of 10,000 to two million daltons. ### Claim 3 (depends on 1) The method of claim 1 wherein said diamine is 1,3-diaminopropane. ### Claim 4 (depends on 1) The method of claim 1 wherein the diamine to periodate used has a molar ratio of greater than 2.2:1. ### Claim 5 (depends on 1) The method of claim 1 wherein the diamine to chemical oxidizing agent used has a molar ratio of about 2.2:1. ### Claim 6 (depends on 1) The aminodextran compounds produced by the method of claim 1. ### Claim 7 (depends on 1) The aminodextran compounds produced by the method of claim 1 wherein said compounds have a degree of sugar substitution in the range of about 3.3% to about 16.5%. ### Claim 8 A method of preparing aminodextran compounds having about 3.3% to about 16.5% of sugar residues doubly-substituted by diamine groups, said method comprising: (a) adding an aqueous periodate solution to an aqueous dextran solution over about a ten minute time period with vigorous stirring during the addition and stemming the resulting reaction mixture at room temperature for about 1.5 to about 3 hours to obtain a mixture wherein the dextran is partially oxidized to dextran aldehyde; (b) desalting and washing the mixture of step (a) to obtain a solution of the polymer dextran-aldehyde; (c) cooling the solution of polymer of step (b) to a temperature of about 5-10.degree. C., adding a diamine to the cooled solution over about a ten minute time period and reacting the resulting mixture for a sufficient time to form Schiff's base, the duration of the reaction being determined by spectroscopic monitoring of the Schiff's base formation and the molar amount of diamine added to the reaction mixture being greater than 2.2 times the molar amount of periodate used in step (a); (d) reducing the Schiff's base by reaction with borohydride anion in aqueous hydroxide at room temperature, the duration of said reaction being determined by spectroscopically monitoring the disappearance of the Schiff's base to yield a reduced aminodextran; and (e) purifying and drying the polymeric product of step (d) to obtain said aminodextran. ### Claim 9 (depends on 8) The method of claim 8 wherein said dextran has a molecular weight in the range of about 10,000 to two million Daltons. ### Claim 10 (depends on 8) The method of claim 8 wherein the diamine and periodate are used in a molar ratio of about 2.2:1. ### Claim 11 (depends on 8) The method of claim 8 wherein said diamine is 1,3-diaminopropane. ### Claim 12 (depends on 8) The method of claim 8 wherein said temperature is in the range of 5-10.degree. C. ### Claim 13 (depends on 8) The method of claim 8 wherein the product of step (d) is purified by dialysis or hollow fiber membrane filtration to optimize yield.