# US 11,998,989 B2 · Method and apparatus for magnetic nanoparticles development with ultra-small size, uniformity and monodispersity > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,998,989 B2 - Document ID: US11998989B2 - Status: Granted - Kind: B2 - Application number: 17/602,409 - Filed: 2020-04-20 - Published: 2022-06-30 - Granted: 2024-06-04 - Earliest claimed: 2019-04-20 - Assignees: Trustees of Dartmouth College - Applicants: Trustees of Dartmouth College - Inventors: John X. J. Zhang; Nanjing Hao; Yuan Nie - Web page: https://patentgrep.com/patent/US11998989B2 ## CPC - B22F 9/24: starting from liquid metal compounds, e.g. solutions - B01J 19/0093: {Microreactors, e.g. miniaturised or microfabricated reactors (laboratory containers with capillary fluid transport in microfabricated channels or chambers B01L3/5027)} - B22F 1/054: Nanosized particles - B22F 1/0547: {Nanofibres or nanotubes} - B22F 1/065: Spherical particles - B22F 1/102: Metallic powder coated with organic material - B22F 1/16: Metallic particles coated with a non-metal (coated with lubricating or binding agents or with organic material B22F1/10) - B22F 1/17: Metallic particles coated with metal - B01F 25/4331: {Mixers with bended, curved, coiled, wounded mixing tubes or comprising elements for bending the flow} - B01F 33/30: Micromixers - B01J 2219/00795: Spiral-shaped - B01J 2219/00891: Feeding or evacuation - B22F 1/05: Metallic powder characterised by the size or surface area of the particles - B22F 2999/00: Aspects linked to processes or compositions used in powder metallurgy - B82Y 40/00: Manufacture or treatment of nanostructures - B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - B01F: MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING (mixing paints B44D3/06) - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES ## Abstract In an embodiment, the present disclosure pertains to a method of making magnetic nanoparticles through the utilization of a microfluidic reactor. In some embodiments, the microfluidic reactor includes a first inlet, a second inlet, and an outlet. In some embodiments, the method includes applying a magnetic nanoparticle precursor solution into the first inlet of the microfluidic reactor through a first flow rate and applying a reducing agent into the second inlet of the microfluidic reactor through a second flow rate. In some embodiments, the magnetic nanoparticles are produced in the microfluidic reactor and collected from the outlet of the microfluidic reactor. In an additional embodiment, the present disclosure pertains to a composition including a plurality of magnetic nanoparticles. In a further embodiment, the present disclosure pertains to a microfluidic reactor. ## Claims ### Claim 1 A method of making magnetic nanoparticles through the utilization of a microfluidic reactor, wherein the microfluidic reactor comprises: a first end, a second end, a spiral shaped microchannel between the first end and the second end, a first inlet and a second inlet, wherein the first inlet and the second inlet are positioned at the first end, and an outlet positioned at the second end, and wherein the method comprises: applying a magnetic nanoparticle precursor solution into the first inlet of the microfluidic reactor through a first flow rate; and applying a reducing agent into the second inlet of the microfluidic reactor through a second flow rate, wherein the first flow rate and the second flow rate provide laminar flow of the magnetic nanoparticle precursor solution and the reducing agent through the microfluidic reactor, and wherein the magnetic nanoparticles are produced in the microfluidic reactor and collected from the outlet of the microfluidic reactor. ### Claim 2 (depends on 1) The method of claim 1, wherein the magnetic nanoparticle precursor solution comprises metal salts, wherein the metal salts are selected from the group consisting of metal chlorides, metal fluorides, metal bromides, metal iodides, and combinations thereof. ### Claim 3 (depends on 1) The method of claim 1, wherein the reducing agents are selected from the group consisting of hydrazine, diborane, sodium borohydride, lithium aluminium hydride, potassium borohydride, ferrous sulfate, stannous chloride, oxalic acid, sodium hydroxide, hydrogen peroxide, hydrochloric acid, and combinations thereof. ### Claim 4 (depends on 1) The method of claim 1, wherein the applying of the magnetic nanoparticle precursor solution and the reducing agent occur simultaneously. ### Claim 5 (depends on 1) The method of claim 1, wherein the applying of the magnetic nanoparticle precursor solution occurs after the applying of the reducing agent. ### Claim 6 (depends on 1) The method of claim 1, wherein the first flow rate and the second flow rate are the same. ### Claim 7 (depends on 1) The method of claim 1, wherein the first flow rate and the second flow rate are different. ### Claim 8 (depends on 1) The method of claim 1, wherein the microfluidic reactor is a continuous microfluidic reactor, wherein the continuous microfluidic reactor provides uninterrupted flow of the magnetic nanoparticle precursor solution and the reducing agent through the microfluidic reactor for the continuous production of magnetic nanoparticles. ### Claim 9 (depends on 8) The method of claim 8, wherein droplets or immiscible phases do not form within the microfluidic reactor. ### Claim 10 (depends on 1) The method of claim 1, wherein the magnetic nanoparticles are formed at room temperature, and wherein the method occurs without heating. ### Claim 11 (depends on 1) The method of claim 1, wherein the spiral shape of the microchannel comprises a plurality of arcs. ### Claim 12 (depends on 1) The method of claim 1, wherein the microchannel comprises widths ranging from 50 μm to 500 μm and heights ranging from 50 μm to 500 μm. ### Claim 13 (depends on 1) The method of claim 1, wherein the magnetic nanoparticles comprise metals, wherein the metals are selected from the group consisting of iron (Fe), cobalt (Co), nickel (Ni), silver (Ag), copper (Cu), gold (Au), platinum (Pt), palladium (Pd), germanium (Ge), and combinations thereof. ### Claim 14 (depends on 1) The method of claim 1, wherein the magnetic nanoparticles have sizes of less than about 10 nm in diameter. ### Claim 15 (depends on 1) The method of claim 1, wherein the magnetic nanoparticles comprise surface areas that range from about 100 m2/g to about 1,000 m2/g. ### Claim 16 (depends on 1) The method of claim 1, wherein the magnetic nanoparticles comprise saturation magnetization values ranging from about 10 emu/g to about 150 emu/g. ### Claim 17 (depends on 1) The method of claim 1, wherein the magnetic nanoparticles have shapes selected from the group consisting of spherical shapes, rod shapes, flower shapes, cubic shapes, and combinations thereof. ### Claim 18 (depends on 1) The method of claim 1, further comprising coating the magnetic nanoparticles, wherein the magnetic nanoparticles are coated with a coating agent selected from the group consisting of silica coatings, polymer coatings, titania coatings, metal coatings, and combinations thereof. ### Claim 19 A method of making magnetic nanoparticles through the utilization of a microfluidic reactor, wherein the microfluidic reactor comprises: a first end, a second end, a spiral shaped microchannel between the first end and the second end, a first inlet and a second inlet, wherein the first inlet and the second inlet are positioned at the first end, and an outlet positioned at the second end, and wherein the method comprises: applying a magnetic nanoparticle precursor solution into the first inlet of the microfluidic reactor through a first flow rate; and applying a reducing agent into the second inlet of the microfluidic reactor through a second flow rate, wherein the applying of the magnetic nanoparticle precursor solution occurs after the applying of the reducing agent, and wherein the magnetic nanoparticles are produced in the microfluidic reactor and collected from the outlet of the microfluidic reactor. ### Claim 20 A method of making magnetic nanoparticles through the utilization of a microfluidic reactor, wherein the microfluidic reactor comprises: a first end, a second end, a spiral shaped microchannel between the first end and the second end, wherein the microchannel comprises widths ranging from 50 μm to 500 μm and heights ranging from 50 μm to 500 μm, a first inlet and a second inlet, wherein the first inlet and the second inlet are positioned at the first end, and an outlet positioned at the second end, and wherein the method comprises: applying a magnetic nanoparticle precursor solution into the first inlet of the microfluidic reactor through a first flow rate; and applying a reducing agent into the second inlet of the microfluidic reactor through a second flow rate, wherein the magnetic nanoparticles are produced in the microfluidic reactor and collected from the outlet of the microfluidic reactor. ### Claim 21 A method of making magnetic nanoparticles through the utilization of a microfluidic reactor, wherein the microfluidic reactor comprises: a first end, a second end, a spiral shaped microchannel between the first end and the second end, a first inlet and a second inlet, wherein the first inlet and the second inlet are positioned at the first end, and an outlet positioned at the second end, and wherein the method comprises: applying a magnetic nanoparticle precursor solution into the first inlet of the microfluidic reactor through a first flow rate; and applying a reducing agent into the second inlet of the microfluidic reactor through a second flow rate, wherein the magnetic nanoparticles are produced in the microfluidic reactor and collected from the outlet of the microfluidic reactor, and wherein the magnetic nanoparticles have sizes of less than about 10 nm in diameter. ### Claim 22 A method of making magnetic nanoparticles through the utilization of a microfluidic reactor, wherein the microfluidic reactor comprises: a first end, a second end, a spiral shaped microchannel between the first end and the second end, a first inlet and a second inlet, wherein the first inlet and the second inlet are positioned at the first end, and an outlet positioned at the second end, and wherein the method comprises: applying a magnetic nanoparticle precursor solution into the first inlet of the microfluidic reactor through a first flow rate; and applying a reducing agent into the second inlet of the microfluidic reactor through a second flow rate, wherein the spiral shaped microchannel provides laminar flow of the magnetic nanoparticle precursor solution and the reducing agent through the microfluidic reactor, and wherein the magnetic nanoparticles are produced in the microfluidic reactor and collected from the outlet of the microfluidic reactor.