COLLOIDS AND SURFACES B-BIOINTERFACES
·
2020
·
IF 4.389
Yi-Ping Cao,Yu-Pei Xia,Xiao-Fei Gu,Li Han,Queting Chen,Gao-Ying Zhi,Dong-Hao Zhang
Here, PEI@PMMA microspheres were prepared by grafting polyethyleneimine (PEI) on poly(methyl methacrylate) (PMMA) magnetic microspheres and successfully used to immobilize lipase. The results showed that PEI@PMMA microspheres had strongly adsorbed lipase (49.1 mg/g microsphere) via electrostatic attraction. To prevent lipase shedding, the adsorbed lipase was further crosslinked with PEI on microspheres using glutaraldehyde as crosslinker. Consequently, PEI-crosslinked lipase (2.14 U/mg) exhibited 2.6 times and 1.4 times higher activity respectively than the directly covalent lipase (0.82 U/mg) and the crosslinked lipase aggregates (1.57 U/mg), which was close to the activity of adsorbed lipase (2.20 U/mg). Conformational analysis from FTIR spectroscopy showed that PEI-crosslinked lipase retained its natural structure well. And the α-helix structure seemed to play a key role in enhancing lipase activity. Furthermore, the effects of various parameters on crosslinking reaction were investigated. Also, PEI-crosslinked lipase revealed higher pH and thermal stability. The Michaelis constant ( K m ) was increased and the optimum temperature of lipase was widened observably after crosslinking with PEI on PEI@PMMA magnetic microspheres.
研究领域:
生物化学
·
酶工程
✓ 已验证
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2019
·
IF 6.393
Shuzhen Dou,Ning Li,Xueyun Wang,Qunyan Zhu,Zhongshun Wang,Nan Lu
Rapid quantification of peptides by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a challenge. Herein, we prepared a super-hydrophobic poly(methyl methacrylate) (PMMA) structured chip for quantifying peptides without internal standard by improving the detection reproducibility and sensitivity. The chip was formed by PMMA microspheres through a self-assembly method. As a good adsorbent of peptides, PMMA microspheres make peptides distributed uniformly on the chip, resulting in the elimination of the coffee ring effect and the homogeneous co-crystallization of peptides/matrix. The relative standard deviations (∼ 10 %) and coefficients of determination (∼ 0.99) are satisfactory when detecting 3 standard peptides, which show that the chip is applicable for rapid quantification of peptides. The limit of detection is improved by 1000-fold on this chip compared with conventional steel target because of the enrichment of the super-hydrophobicity. It can be concluded that the detection reproducibility and sensitivity are significantly improved by the super-hydrophobic structured-PMMA chip. The applicability of the chip for practical samples is demonstrated by quantifying bacitracin A in milk extract and bradykinin1-7 in serum with good linearities. The structured-PMMA chips exhibit competitive advantages for quantitative analysis of peptides, which have a great potential for proteomic research.
研究领域:
分析化学
·
生物医学工程
·
蛋白质组学
✓ 已验证
产品关联
DOI
高影响因子
COLLOID AND POLYMER SCIENCE
·
2023
·Vol. 301
·期 6
·655-663
·
IF 2.4
Wang Zhen,Leng Kangwei,Liu Jiuhong,Li Yueqiu,Liu Shucheng,Li Yan,Wang Zhongwei,Yu Qing,Han Yuxi
Poly(methyl methacrylate) microspheres with narrow particle size distribution were synthesized successfully under visible light (LED@420 nm) in this study, and no RAFT agent was involved. A novel acylphosphine oxide, (2,4-dimethylphenyl) phenylphosphine oxide (2,4-DMTPO), was used as the photoinitiator. Uniform microspheres with the weight-average diameter (D w ) of 1.03 μm and polydispersity index (PDI) of 1.06 were obtained upon irradiation for 30 min, when the ratio of methyl methacrylate (MMA) to solvent was 1:10, the amount of polyvinylpyrrolidone (PVP) and 2,4-DMTPO was 30 wt% and 2 wt% of MMA, respectively. However, no microspheres could be detected instead of large blocks when (2,4,6-trimethylbenzoyl) diphenylphosphine oxide (TPO) was the photoinitiator under the same condition. It could be due to the higher light absorption ability and quantum yield of 2,4-DMTPO at 420 nm than TPO. A possible formation mechanism of PMMA microspheres was proposed and the effects of photoinitiator, MMA, irradiation time, and PVP were discussed. Results shown that regular microspheres were formed when the irradiation time exceeded 30 min, and the amount of PVP was in the range of 25 to 40 wt% of MMA. Lowering the amount of photoinitiator to 0.5 wt% resulted in ca. 66% and 4% decrease of D w and PDI, respectively. This study may provide a rapid and energy saving way of synthesizing monodispersed PMMA microsphere, which would be benefit for the fields of coating, template, and so on.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2022
·Vol. 15
·期 19
·6553
·
IF 3.748
Yuan Zhao,Tian Liang,Pengpai Miao,Tao Chen,Xiaobing Han,Guowen Hu,Jie Gao
The modification of polymers can significantly improve the ability to remove rare earth ions from wastewater, but so far few studies have focused on the irradiation-induced grafting method. In this study, a novel magnetic chelating resin for Ce(III) uptake was first synthesized by suspension polymerization of PMMA@Fe3O4microspheres followed by irradiation-induced grafting of glycidyl methacrylate (GMA) and subsequent amination with polyethyleneimine (PEI). The FT-IR, SEM, TG and XRD characterization confirmed that we had successfully fabricated magnetic PMMA-PGMA-PEI microspheres with a well-defined structure and good thermal stability. The obtained adsorbent exhibited a satisfactory uptake capacity of 189.81 mg/g for Ce(III) at 318.15 K and an initial pH = 6.0. Additionally, the impact of the absorbed dose and GMA monomer concentration, pH, adsorbent dosage, contact time and initial concentration were thoroughly examined. The pseudo-second order and Langmuir models were able to describe the kinetics and isotherms of the adsorption process well. In addition, the thermodynamic data indicated that the uptake process was spontaneous and endothermic. Altogether, this research enriched the Ce(III) trapping agent and provided a new method for the removal rare earth pollutants.Keywords:magnetic PMMA microspheres;PEI;radiation induced grafting;Ce(III) adsorption
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2025
·
IF 3.8
Yansong Liu,Yongsheng Liu,Yejie Cao,Xiang Zheng,Xiaokun Sun,Yang Xu
Dual porous yttria-stabilized zirconia (YSZ) ceramics were fabricated via digital light processing (DLP) additive manufacturing using polymethyl methacrylate (PMMA) microspheres as pore-forming agent for the first time. The results showed that the introduction of PMMA microspheres effectively reduced the viscosity of the photosensitive YSZ ceramic slurry used in DLP printing, improved the cured depth of the slurry, and did not exert a strong influence on stability. After sintering at 1400°C, pores with dual scales were generated in the ceramics, while exhibiting the optimal physical and mechanical properties. With the increase of PMMA content from 0 to 40 vol%, the open porosity increased from 1.96% to 34.06% and the density decreased from 5.92 to 3.82 g/cm 3 , respectively. The compressive strength and thermal conductivity of porous ceramics decreased from 350.54 to 99.85 MPa and from 2.80 to 1.46 W/(m⋅K), respectively. This investigation opens up new prospects for the fabrication of porous YSZ ceramics with low thermal conductivity and high mechanical properties.
研究领域:
材料科学
·
增材制造
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2023
·
IF 5.1
Siyuan Yu,Yanting Zhou,Chunyue Zhao,Han Liu,Zhiyun Xue,Jinfeng Xing
Dispersion photopolymerization was carried out under green LED irradiation to rapidly prepare monodisperse poly(methyl methacrylate) (PMMA) microspheres with small size by using a high-efficient three-component initiating system. The polymerization parameters including exposure time, MMA content, stirring speed, water ratio and PVP content were systematically investigated. Crucial parameters were further optimized by response surface method (RSM), and a corresponding polymerization mechanism was proposed. Finally, PMMA microspheres with 375.6 nm of size and 0.101 of PDI were prepared. This study provides a facile method for the rapid fabrication of PMMA microspheres.
研究领域:
材料科学
·
高分子化学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2013
·
IF 5.521
Jianbo Tan,Xin Rao,Jianwen Yang,Zhaohua Zeng
Highly monodisperse PMMA microspheres have been synthesized by photoinitiated RAFT dispersion polymerization in the presence of a Macro-RAFT agent and a small molecular RAFT agent. A particle yield of over 90% was achieved within 3 h under UV irradiation at room temperature. The Macro-RAFT agent acts as a stabilizer and stabilizes the particles via formation of block copolymers in situ, and XPS analysis shows that about 29.9% of the particle surface was covered by the stabilizer. Various surface functional microspheres were prepared by using four kinds of Macro-RAFT agents, including poly(methoxy poly(ethylene glycol) acrylate)-based trithiocarbonate (P(mPEGA)-TTC), poly(methoxy poly(ethylene glycol) acrylate-co-acrylic acid)-based trithiocarbonate (P(mPEGA-co-AA)-TTC), poly(acrylic acid)-based trithiocarbonate (PAA-TTC), and poly(methoxy poly(ethylene glycol) acrylate-co-4-vinylpyridine)-based trithiocarbonate (P(mPEGA-co-4VP)-TTC). Ag/PMMA nanocomposite spheres were prepared using the P(mPEGA-co-AA)-TTC stabilized microspheres. The PAA-TTC stabilized microspheres showed pH sensitivity. The colloidal stability of the particles prepared by this photoinitiated RAFT dispersion polymerization was also investigated.
研究领域:
高分子化学
·
材料科学
·
纳米技术
·
胶体与界面科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 24
·18922-18931
·
IF 3.84
Jianbo Tan,Xin Rao,Jianwen Yang,Zhaohua Zeng
Cross-linked PMMA microspheres have been synthesized by photoinitiated RAFT dispersion polymerization with dipropylene glycol diacrylate (DPGDA) or trimethylolpropane triacrylate (TMPTA) as the cross-linker. Monodisperse microspheres were obtained in the presence of 0.5 wt% S,S′-bis(α,α′-dimethyl-α′′-acetic acid) trithiocarbonate (BDMAT, a RAFT agent) with DPGDA concentration up to 5 wt% or TMPTA concentration up to 2 wt%. The particle formation process was investigated, and the results reveal that the cross-linking reaction was retarded to a certain extent by the RAFT process, which is crucial for the formation of uniform particles under high cross-linker concentrations. The phase diagrams for the methodology have been built up, and show that the procedure could only give polydisperse microspheres at a low DPGDA concentration or coagulum at a high DPGDA concentration in the absence of a RAFT agent, and monodisperse microspheres were obtained at DPGDA concentration up to 5 wt% when the RAFT agent concentration reached an appropriately high level, e.g. 0.5 wt% BDMAT or 0.75 wt% DDMAT. By adjusting the reaction conditions, we have prepared monodisperse cross-linked PMMA microspheres with 10 wt% DPGDA added at the beginning of the reaction. Furthermore, we have functionalized the cross-linked microspheres by adding a functional comonomer to the system at the beginning of polymerization, or by surface-initiated RAFT polymerization via the RAFT groups attached on the particle surface.
研究领域:
材料科学
·
高分子化学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）