Size-Controlled Synthesis of Carboxyl-Functionalized Magnetite Particles: Effects of Molecular Weight of the Polymer and Aging

Abstract

Magnetic particles (MPs) are of great interest in many varied applications in the fields of biotechnology, biomedicine, and environmental remediation. To accommodate different applications, size-control synthesis of MPs is of particular interest. Here, we report a simple synthesis of MPs in the range of nano to microsize (23 nm to 1.2 μm). Specifically, the particle size of MPs was tuned by the (i) molecular weight (M w ) of poly(acrylic acid) (PAA) and (ii) aging process. Three different hydrothermal procedures using different M w of PAA were compared, namely, one-step hydrothermal, two-step hydrothermal, and coating-after hydrothermal methods. The M w of PAA used was 1.8k, 30k, 50k, and 100k g/mol. The resulted particle sizes of the onestep hydrothermally synthesized 1.8k, 30k, 50k, and 100k MPs were 1202 ± 359, 447 ± 156, 418 ± 88, and 247 ± 34 nm, respectively, and those of the two-step ones were 23 ± 3, 100 ± 14.1, 116 ± 26, and 78 ± 6 nm, respectively. The crystal composition, ζ-potentials, magnetic properties, magnetic separation efficiencies, and protein conjugation properties were studied systematically. The results showed that MPs synthesized via one-step hydrothermal synthesis demonstrated the highest yield and the highest magnetic separation efficiency. Bovine serum albumin, lysozyme, and enhanced green fluorescent protein as protein models were successfully conjugated with the MPs, and the application of antibody-conjugated PAA-MPs for bacterial capture was demonstrated.

Fabrication of Epsilon-Polylysine-Based Magnetic Nanoflowers with Effective Antibacterial Activity against Alicyclobacillus acidoterrestris

“…After that, 12 mL of N 2 H 4 ·H 2 O solution was added into the mixture and continually stirred for another 1 h, followed by transferring into a 100 mL sealed Teflon autoclave. After being maintained at 180 °C for 10 h, the obtained products were magnetically isolated, thoroughly washed with DI water, and dried at 60 °C to obtain spherical Fe 3 O 4 NPs …”

“…After being maintained at 180 °C for 10 h, the obtained products were magnetically isolated, thoroughly washed with DI water, and dried at 60 °C to obtain spherical Fe 3 O 4 NPs. 24 Fe 3 O 4 @MoS 2 NPs were synthesized by a facile hydrothermal method. 25 In detail, 50.0 mg of synthesized Fe 3 O 4 NPs were ultrasonically (150 W) dispersed in 60 mL of DI water, after which 2.1 g of ammonium molybdate tetrahydrate and 4.6 g of thiourea were added into the mixture with ultrasonication (150 W) for 30 min.…”

CoFe2O4@SiO2@TiO2 core-shell nanoparticles for photocatalytic water decontamination

“…(2.0  0.1) mg of the dried cobalt ferrite particles were put in a glass beaker [14,15]. Then, 0.54 mL of water and 13 mL of ethanol were added and a sonication process was carried out for 20 min.…”

Preparation and Application of Magnetite (Fe3O4) Nanoparticles by Co-precipitation Method for Removal Rhodamine B in Wastewater

“…After adsorption, Fe3O4 can be separated from the medium by a simple magnetic process. Thus, the economical, scalable, non-toxic and efficient synthesis of Fe3O4 nanoparticles is of great interest for potential applications and fundamental research (Eskandari, 2021;Song, 2018). However, pure Fe3O4 is easily oxidized and easily agglomerates in water (Demirezen, 2022).…”