Bo Yang,Guo-Ling Li,Hai-Lin Cong,Bing Yu,Lei Wang,Shu-Jing Yang
In this study, we prepared a porous poly (glycidyl methacrylate) (PGMA) microsphere by modified seed-swelling emulsion polymerization. The structure and morphology of the porous microspheres were characterized by SEM. We discussed the effect of the ratio of crosslinker and monomer on microsphere formation and micropores, and found the most favorable conditions for the preparation of porous PGMA microspheres. The great structure and specific surface area of the porous microspheres and the active functional groups on the surface indicate a wide range of applications.
Tianhao Xia,Yuwen Yuan,Yunpeng Wang,Pragati Awasthi,Wenkun Dong,Xvsheng Qiao,Dong Chen,Shisheng Ling,Xianping Fan
This study aims to advance the development of magnetic fluorescent polymer microspheres for biomedical detection applications. Conventionally, dopants have utilized europium(III) (Eu(III)) organic complexes due to their high compatibility with polymers and strong fluorescence. However, as the common magnetic material Fe 3 O 4 can quench their fluorescence, it is hard to synthesize Eu complex-doped magnetic fluorescent materials. To maintain fluorescence in the presence of magnetic parts, in this work, we synthesized Eu-doped magnetic microspheres with multi-layered structure. Firstly, poly-(glycidyl methacrylate) (PGMA) microspheres were prepared as templates and subsequently coated with layers of Fe 3 O 4 and SiO 2 . Then, the synthesized Eu(TTA) 3 (TPPO) 2 were added into PGMA@Fe 3 O 4 @SiO 2 microspheres in either basic or acidic conditions, and covered them with an extra sol–gel layer of silica at the same time. The microspheres exhibit a core–shell structure with sub-micron dimensions (580 nm) and possess favorable superparamagnetic properties ( M s = 22.02 A·m 2 /kg, M r = 1.37 A·m 2 /kg, H c = 0.242 A/m). But the fluorescence of Eu 3+ are significantly quenched by Fe 3 O 4 , O–H oscillators, and N–H oscillators. Finally, to exclude the quenching mentioned above, the first pure SiO 2 shielding layer and the second Eu(TTA) 3 (TPPO) 2 -dispersed SiO 2 layer were coated onto PGMA@Fe 3 O 4 microspheres to prevent the energy transfer due to the quenching centers and hold the fluorescence of Eu 3+ . These findings underscore the considerable potential of these microspheres exhibiting rapid magnetic separation and stable fluorescence for bioimaging and biosensing applications.
The separation of target substances is a significant biological detection procedure, where magnetic microspheres can act as high-performance separation materials. However, challenges are still kept to fulfill all the requirements. A submicron magnetic poly (glycidyl methacrylate) (PGMA) microsphere was synthesized in this investigation by utilizing three distinct techniques: in situ coprecipitation, electrostatic self-assembly, and silica surface coating. The PGMA microspheres were initially produced through a soap-free emulsion polymerization technique, wherein the coagulation process was governed by surface charge density. This factor additionally impacted the size and monodispersity of the microspheres. Then, we discovered that the capping agent sodium citrate (Na 3 Cit) effectively regulated the superparamagnetism properties of magnetic microspheres; the critical size of the superparamagnetic was 10.9 nm. Furthermore, the concentration of Fe 2+ and Fe 3+ effectively regulated the saturation magnetization, a property that correlated with the nucleation rate of the Fe 3 O 4 crystal. Additionally, we demonstrated that the pH regulated the electrostatic self-assembly, and it was suggested that positively charged PGMA–NH 2 microspheres and negatively charged Fe 3 O 4 nanoparticles be tightly coupled. For application, the PGMA@Fe 3 O 4 microspheres were subsequently coated with SiO 2 , which had been surface-modified with carboxyl groups. The PGMA@Fe 3 O 4 and carboxyl-modified microspheres exhibited saturated magnetization values of 23.73 and 17.73 emu/g, respectively. These microspheres have been effectively utilized for the extraction of DNA from various sources such as Salmonella typhi, monkeypox virus, and clinical swab samples, suggesting the potential of these microspheres for nucleic acid separation in the biomedical domain.
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