実験報告書様式（一般利用課題・成果公開利用）（ ※本報告書は英語で記述してください。ただし、産業利用課題として採択されている方は日本語で記述していただいても結構です。 ）提出日 Date of Report

Experimental Report

November 29, 2012

装置責任者 Name of responsible
person: Dr. Jun-ichi Suzuki
実験課題名 Title of experiment
Small-angle neutron scattering studies on the adsorption of DNA 装置名 Name of Instrument/（BL No.）by cationic diblockcopolymer micelles in aqueous solutions
BL-15 (TAIKAN)
実験責任者名 Name of principal investigator
実施日時 Date and time of Experiment
June12 (Tue) 21:00 - June 13 (Wed) 9:00
Tsang-Lang Lin
am and June 13 (Wed) 21:00 - June 16
所属 Affiliation(Sat) 10:00 am
National Tsing Hua University (TAIWAN)
課題番号 Project No. 2012A0100

試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.
1.

diblock copolymer poly(styrene-b-N-methyl-4-vinyl pyridinium iodide (PS-P4VPQ),(CH2CHC6H5)n-(CH2CHC5H4NCH3I)m, dissolved in D2O.

2. DNA, C232 N92O139P22, dissolved in D2O

2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results.

If you failed to conduct experiment as planned, please describe reasons.

The SANS measurements were conducted at the BL-15 (TAIKAN) of J-PARC. Fig. 1 shows the measured
SANS profiles of the PS-P4VPQ diblockcopolymer micelles in D2O at 0.1, 0.2, 0.3, 0.4, and 0.5 mM
concentrations. The data reduction program was not yet fully developed during the period of this experiment andthe scattering data from different neutron wavelength deviates slightly from each group which caused the spreadof the scattering intensity. This problem will be fixed later by reducing all the data appropriately once the data
reduction software is fully developed. The measured scattering profiles are all similar for different concentrations
with a feature of globular micelle particle of around 15~20 nm in diameter. It seems that the cationicdiblockcopolymer form very stable micelles. The tendency to grow into cylindrical shape is small as theconcentration is increased. This could be attributed to the highly asymmetric size of the hydrophobic part and thehydrophilic part of this diblockcopolymer. When DNA is added into the diblockcopolymer micelle solution, thescattering profile is dramatically changed from globular micelles to larger aggregates, which are confirmed assoft cylindrical micelles by TEM. An interference peak occurs around Q=0.032 1/A for the cases with DNA.

1

2. 実験方法及び結果（つづき） Experimental method and results (continued)
This interference peak is likely due to the DNA adsorbed around the cylindrical diblockcopolymer. The
first interference fringe occurs at around Q=0.06 1/A for the diblockcopolymer micelle without DNA. Thismeans that DNA is basically adsorbed to the surface of the diblockcopolymer micelles at least not too deep into
the brush layer (such as the case of DNA adsorption by the planar cationic diblockcopolymer monolayer at theair-water interface). As revealed by TEM and a similar study indicated that DNA would wrap tightly around thecylindrical cationic micelle helically. This SANS study shows that the adsorption of DNA could induce structuraltransformation of the diblockcopolymer micelles.

I(Q) (cm-1)

101

0.1

0.01

0.1 mM CP4571
0.2 mM CP4571
0.3 mM CP4571
0.4 mM CP4571
0.5 mM CP4571
0.1

Q (Å-1)

Fig. 1 The measured SANS profiles of the PS-P4VPQ diblockcopolymer with molecular weight of
3.5K-28.0K at different concentrations.

10I(Q) (cm-1)

10.1

0.01

0.4 mM CP4571
With 1.68 µM DNA
With 3.36 µM DNA
With 6.72 µM DNA
With 10.08 µM DNA
With 13.44 µM DNA
With 16.80 µM DNA
With 20.16 µM DNA*All DNA are 700 b.p.

0.1-1

Q (Å )

Fig. 2 The measured SANS profiles of the 0.4 mM PS-P4VPQ diblockcopolymer with molecular weight of
3.5K-28.0K mixed with different amounts of DNA in D2O at 25 C.
2