Electronic Supplementary Material
Preparation of Surface Imprinted Particles with Metal Chelating Strategy for Albumin Recognition
Qinran Li1,2, Kaiguang Yang1, Senwu Li1,2, Lukuan Liu1,2,Lihua Zhang1*,Zhen Liang1, Yukui Zhang1
1 Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R.&.A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
2 University of Chinese Academy of Sciences, Beijing 100039, China
* Correspondence: Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China. Tel. &: +86 411 84379720; E-mail:
1. The main reaction of the MIP particles preparation
Scheme S1. Principle of the main reaction for the MIP preparation: (a) composition of IDA-GLYMO; (b) modification of vinyl group; (c) modification of IDA group; (d) modification of aminopropyl group; (e) metal chelating reaction between IDA group and copper ion.
2. Calculation of the double bonds modified on the silica
Vinyl groups modified on the surface of the silica particles could improve the polymerization and was critical for the forming of the imprinting polymer shell. In our research, the amount of vinyl groups modified on the surface of silica was determined through the reaction of bromine addition and iodometry. The addition reaction occurred between Br2 (produced by the reaction of KBrO3 and KBr under acidic conditions) and the vinyl groups at the surface of silica particles. And then the excessive Br2 as consumed by KI to form I2, which could be quantitated through titrating with Na2S2O3, and the starch solution was used as an indicator. In our research, the turbid liquid contained vinyl-silica reacted with the excessive Br2, which was calculated by the following iodometric method. Blank control was used commensurable Br2 above but without the vinyl-silica added. The dissimilarity of Br2 between with and without vinyl-silica, which was calculated by iodometric method, was the wasting Br2 in the addition reaction. As a result, the amount of double bonds could be acquired due to the ratio of vinyl and Br2 was 1:1 in this addition reaction.
Scheme S2. Principle of bromine addition and iodometry
By the help of Br2 addition reaction, we could calculate the double bonds on the surface of silica and the current reacted condition was suitable to modify vinyl groups on the silica. The silica without modified vinyl groups was as the blank. The concentration of the vinyl groups at the surface of silica particles is could be defined as:
（1）
Where E is the concentration of the double bonds at the surface of silica particles (μmol/g), Vb is the volume of Na2S2O3 standard solution consumed in the blank experiment (L), Vs is the volume of Na2S2O3 standard solution consumed in the sample experiment (L), C is the concentration of Na2S2O3 standard solution (μmol/L), and m is the mass of silica particles (g).
Silica particles were mixed with 50.0 μL VPTMS in 2.0 mL methanol and the concentration of the double bonds at the surface of silica was 26.0±1.41 μmol/g, which was calculated by Eq.(1). The result of this measurement above was indicated that the vinyl groups was modified successfully on the surface of the silica.
3. SEM observation
For scanning electron microscopy (SEM) imaging, imprinting particles (2 mg) were washed with ethanol, and then were dried at 70 °C for 2 hours, followed by sputter coating with gold. A JSM-6360LV scanning electron microscope (JEOL, Hitachi, Japan) was applied for the SEM measurement.
SEM image was measured for the size and shape of these surface imprinting core-shell particles. As shown in Fig. S1, the particles were regular spherical, with the particle size of about 5μm. Neither aggregation nor incompact solidified polymer could be observed among the core-shell particles. This phenomenon indicated that the polymerization was mainly occurred on the surface of particles, which was the presupposition of surface imprinting achieved.
Figure S1 SEM image of the PSA imprinting particles with metal chelating strategy (magnification×10000)
4. Selectivity of MIP and NIP particles prepared by sol-gel strategy
Figure S2. Selectivity of MIP and NIP particles prepared by sol-gel strategy for four proteins with different Mw, hydrophilic and pI. 20mg MIP or NIP particles were respectively incubated in 10 mM phosphate buffer at pH 7.4 containing PSA, RNB, Cyt-c and Mb with each concentration 0.30 mg/mL at 4 °C for 24h. The result was obtained by the duplicate experiments