title: Enzymatic synthesis of magnetic nanoparticles.
abstract: We report the first in vitro enzymatic synthesis of paramagnetic and antiferromagnetic nanoparticles toward magnetic ELISA reporting. With our procedure, alkaline phosphatase catalyzes the dephosphorylation of l-ascorbic-2-phosphate, which then serves as a reducing agent for salts of iron, gadolinium, and holmium, forming magnetic precipitates of Fe45±14Gd5±2O50±15 and Fe42±4Ho6±4O52±5. The nanoparticles were found to be paramagnetic at 300 K and antiferromagnetic under 25 K. Although weakly magnetic at 300 K, the room-temperature magnetization of the nanoparticles found here is considerably greater than that of analogous chemically-synthesized LnxFeyOz (Ln = Gd, Ho) samples reported previously. At 5 K, the nanoparticles showed a significantly higher saturation magnetization of 45 and 30 emu/g for Fe45±14Gd5±2O50±15 and Fe42±4Ho6±4O52±5, respectively. Our approach of enzymatically synthesizing magnetic labels reduces the cost and avoids diffusional mass-transfer limitations associated with pre-synthesized magnetic reporter particles, while retaining the advantages of magnetic sensing.
authors: Department of Chemistry and Texas Center for Superconductivity, University of Houston, Houston, TX 77204, USA. akolhatkar@uh.edu.
authors: Arati G
authors: AG
authors: Kolhatkar
authors: Department of Physics and Astronomy, University of Texas at Brownsville, Brownsville, TX 78520, USA. chamath.dannangoda@gmail.com.
authors: Chamath
authors: C
authors: Dannongoda
authors: Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204, USA. edkourentzi@uh.edu.
authors: Katerina
authors: K
authors: Kourentzi
authors: Department of Chemistry and Texas Center for Superconductivity, University of Houston, Houston, TX 77204, USA. ajamison@uh.edu.
authors: Andrew C
authors: AC
authors: Jamison
authors: Department of Electrical and Computer Engineering, University of Houston, Houston, TX 77204, USA. inekrashevich@gmail.com.
authors: Ivan
authors: I
authors: Nekrashevich
authors: Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204, USA. archana.kar@gmail.com.
authors: Archana
authors: A
authors: Kar
authors: Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204, USA. eecacao@gmail.com.
authors: Eliedonna
authors: E
authors: Cacao
authors: Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA. ustrych@gmail.com.
authors: Ulrich
authors: U
authors: Strych
authors: Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, TX 77204, USA. rusakova@uh.edu.
authors: Irene
authors: I
authors: Rusakova
authors: Department of Physics and Astronomy, University of Texas at Brownsville, Brownsville, TX 78520, USA. Karen.Martirosyan@utb.edu.
authors: Karen S
authors: KS
authors: Martirosyan
authors: Department of Electrical and Computer Engineering, University of Houston, Houston, TX 77204, USA. litvinov@uh.edu.
authors: Dmitri
authors: D
authors: Litvinov
authors: Department of Chemistry and Texas Center for Superconductivity, University of Houston, Houston, TX 77204, USA. trlee@uh.edu.
authors: T Randall
authors: TR
authors: Lee
authors: Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204, USA. willson@uh.edu.|Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA. willson@uh.edu.|Centro de Biotecnología FEMSA, Departamento de Biotecnología e Ingeniería de Alimentos, Tecnológico de Monterrey, Campus Monterrey, Monterrey, NL 64849, Mexico. willson@uh.edu.
authors: Richard C
authors: RC
authors: Willson
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism*; D001205:Ascorbic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005682:Gadolinium / Q000737:chemistry; D006695:Holmium / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D058185:Magnetite Nanoparticles / Q000737:chemistry*
chemical_list: D058185:Magnetite Nanoparticles; C011669:ascorbate-2-phosphate; D005682:Gadolinium; D007501:Iron; D000469:Alkaline Phosphatase; D001205:Ascorbic Acid; D006695:Holmium