近來表面增強拉曼散射基板以具有表面電漿共振特性的金屬材料(金或銀)和2D平面結構材料(石墨烯和硫化鉬)為主，而且這些材料也已經有完整且豐富的報導，但是具有表面電子轉移特性的磁性奈米氧化鐵材料卻很少有表面增強拉曼的研究。因此，我們提出一種合成磁性氧化鐵的方法-以聯胺輔助水熱法，使得奈米氧化鐵同時具有磁性與表面電子轉移特性，達到以物理吸附而非共價鍵方式增強拉曼散射。我們將0.5 mM的亞甲基藍(methylene blue)與氧化鐵奈米晶體(nanocrystal)混合，發現混和後亞甲基藍的峰值位移4 cm-1，而且具有447.10/1621.54的高峰值比，也表示著亞甲基藍是以C-S-C垂直吸附於奈米氧化鐵的表面，並且讓表面電子轉移(charge transfer)導致表面增強拉曼散射。此增強效應可以使亞甲基藍在相同濃度下的訊號增強2-3倍，並且利用吸收光譜計算出亞甲基藍吸附於氧化鐵的吸附量，計算出來增強因子(enhancement factor)為103-104。另外，我們利用四種表面帶電染劑與表面帶負電的奈米氧化鐵混和，以及利用亞甲基藍分別與表面修飾正、負電性的聚介電質混和的拉曼增強實驗，證明氧化鐵與亞甲基藍是因為靜電吸附導致表面增強拉曼散射。除此之外，我們發現除了以物理吸附方式增強拉曼外，還有化學鍵結增強拉曼。我們將氧化鐵與多巴胺混和，使氧化鐵表面上的苯三酸或檸檬酸鈉與多巴胺上的烯二醇形成配位基，並且發現在混和四小時後，多巴胺的拉曼訊號有明顯提升，也就是說表面增強拉曼技術可以隨時間監控配位狀況。最後，我們利用奈米氧化鐵的磁導引特性，增加表面增強拉曼散射效應以及拉曼偵測的靈敏度，達到一個有電性選擇的磁控制表面電子轉移增強拉曼散射平台。

Non-metal surface-enhanced Raman scattering (SERS) has attracted considerable attention due to its new vision on the determination of the surface chemistry from the electron transfer between molecules and non-metal SERS substrate. In comparison to popular plasmonic nanoparticles (Au and Ag) and 2D materials (graphene and MoS2), the development of magnetic iron oxide nanoparticle to achieve SERS of molecules is very useful to manipulate the signal improvement by magnetic concentration under an external magnetic field, but is very limited to be report yet. Thus, we have demonstrated the N2H4-assisted hydrothermal synthesis of very pure Fe3O4 nanocrystals to be capable of the non-covalent surface enhanced Raman scattering of electrostatic attached dye molecules. With mixture of methylene blue (MB) molecule as probe below 0.5 mM, ~ 4 cm-1 hypsochromic shift and high 447.10/1621.54 peak ratio were observed, showing that a vertical plane of C-S-C skeleton structure of MB absorbed on the surface of Fe3O4 nanocrystals and thus evoke the SERS via charge transfer (CT) process. The signal improvement is 2-3 fold increase of intensity with 103-104 of enhancement factor in contrast to the same MB concentration in the bulk solution. Furthermore, the charge selectivity of four dyes to the Fe3O4(-)- and Fe3O4@polyelectrolyte(+)/(-)-based SERS property was determined. In addition to the physisorption, the ligand exchange reaction of Fe3O4@TMA/citrate with endiol group at the dopamine at least 6 h could be in-situ monitor with such Fe3O4-evolved SERS analysis method. Additional examinations with different fraction of Fe3O4 and γ-Fe2O3 nanocrystals resulted in the non-covalent SERS of MB molecules with different absorption orientation. This surface-dependent CT SERS platform with magnetic iron oxide nanocrystals provides additional function of easy separation for improving signal intensity and sensitive to surface chemistry of molecule charges and complex environments.

[1] O. Veiseh, J. W. Gunn and M. Zhang, Adv Drug Deliv Rev, 2010, 62, 284-304.
[2] C. C. Huang, P. Y. Chang, C. L. Liu, J. P. Xu, S. P. Wu and W. C. Kuo, Nanoscale, 2015, 7, 12689-12697.
[3] M. J. Chiu, S. Y. Yang, H. E. Horng, C. C. Yang, T. F. Chen, J. J. Chieh, H. H. Chen, T. C. Chen, C. S. Ho, S. F. Chang, H. C. Liu, C. Y. Hong and H. C. Yang, ACS Chem Neurosci, 2013, 4, 1530-1536.
[4] M.-C. Hsieh, J.-H. Chen, Y.-F. Tong and S.-H. Liao, Sensors and Actuators A: Physical, 2017, 261, 1-8.
[5] S. Laurent, D. Forge, M. Port, A. Roch, C. Robic, L. V. Elst, and R. N. Muller, Chem Rev, 2008, 108, 2064-2110
[6] M. Y. Liao, P. S. Lai, H. P. Yu, H. P. Lin and C. C. Huang, Chem Commun (Camb), 2012, 48, 5319-5321.
[7] M.-Y. Liao, C.-H. Wu, P.-S. Lai, J. Yu, H.-P. Lin, T.-M. Liu and C.-C. Huang, Advanced Functional Materials, 2013, 23, 2044-2051.
[8] H. A. Garcia, R. P. de Melo, A. Azevedo and C. B. de Araújo, Applied Physics B, 2013, 111, 313-321.
[9] M. Ando, K. Kadono, M. Haruta, T. Sakaguchi, M. Miya, Nature 1995, 374, 625-625.
[10] N. Lee, P. J. Schuck, P. S. Nico and B. Gilbert, J Phys Chem Lett, 2015, 6, 970-974
[11] J. Kneipp, ACS Nano, 2017, 11, 1136-1141.
[12] K. Ulbrich, K. Hola, V. Subr, A. Bakandritsos, J. Tucek and R. Zboril, Chem Rev, 2016, 116, 5338-5431.
[13] L. Gao, J. Zhuang, L. Nie, J. Zhang, Y. Zhang, N. Gu, T. Wang, J. Feng, D. Yang, S. Perrett and X. Yan, Nat Nanotechnol, 2007, 2, 577-583.
[14] Z. Wu, K. Yu, S. Zhang, and Y. Xie, J Phys Chem C, 2008, 112, 11307–11313.
[15] W. Shi, H. Zeng, Y. Sahoo, T. Y. Ohulchanskyy, Y. Ding, Z. L. Wang, M. Swihart, and P. N. Prasad, Nano Lett, 2006, 6, 875-881
[16] J. Lee, J. Yang, H. Ko, S. Oh, J. Kang, J. Son, K. Lee, S. W. Lee, H. G. Yoon, J. S. Suh, Y. M. Huh and S. Haam, Advanced Functional Materials, 2008, 18, 258-264.
[17] W. H. Hung, M. Aykol, D. Valley, W. Hou and S. B. Cronin, Nano Lett, 2010, 10, 1314-1318.
[18] A. Mezni, I. Balti, A. Mlayah, N. Jouini and L. S. Smiri, The Journal of Physical Chemistry C, 2013, 117, 16166-16174.
[19] P. Gong, H. Li, X. He, K. Wang, J. Hu, W. Tan, S. Zhang and X. Yang, Nanotechnology, 2007, 18, 285604.
[20] L. Yang, Z. Bao, Y. Wu and J. Liu, Journal of Raman Spectroscopy, 2012, 43, 848-856.
[21] L. Ai, C. Zeng and Q. Wang, Catalysis Communications, 2011, 14, 68-73.
[22] Y. Lu, Y. Yin, B. T. Mayers, and Y. Xia, Nano Lett, 2002, 2, 183-186
[23] L. Cheng, S. Zhang, Y. Wang, G. Ding and Z. Jiao, Materials Research Bulletin, 2016, 73, 77-83.
[24] Y. Chen, L. Chen, L. Chen and J. Zhang, Particle & Particle Systems Characterization, 2015, 32, 893-898.
[25] S. Chidambaram, B. Pari,N. Kasi, S. Muthusamy, Journal of Alloys and Compounds, 2016, 665, 404-410
[26] L. E. Jennings and N. J. Long, Chem Commun (Camb), 2009, DOI: 10.1039/b821903f, 3511-3524.
[27] H. B. Na, I. C. Song and T. Hyeon, Advanced Materials, 2009, 21, 2133-2148.
[28] E. Gullotti, and Y. Yeo, Molecular Pharmaceutics, 2009, 6, 1041–1051
[29] Y. Matsumura, Jpn J Clin Oncol, 2008, 38, 793-802.
[30] M. Yokoyama, J Artif Organs, 2005, 8, 77-84.
[31] C. C. Lee, E. R. Gillies, M. E. Fox, S. J. Guillaudeu, J. M. J. F. chet, E. E. Dy, and F. C. Szoka, Proc Natl Acad Sci USA, 2006, 103, 16649 -16654
[32] K. E. Uhrich, S. M. Cannizzaro, R. S. Langer and K. M. Shakesheff, Chemical Reviews, 1999, 99, 3181-3198.
[33] E. Soussan, S. Cassel, M. Blanzat and I. Rico-Lattes, Angew Chem Int Ed Engl, 2009, 48, 274-288.
[34] C. Xu, J. Xie, D. Ho, C. Wang, N. Kohler, E. G. Walsh, J. R. Morgan, Y. E. Chin and S. Sun, Angew Chem Int Ed Engl, 2008, 47, 173-176.
[35] C. Xu, B.Wang, and S. Sun, J Am Chem Soc, 2009, 131, 4216–4217
[36] S. Santra, C. Kaittanis, J. Grimm and J. M. Perez, Small, 2009, 5, 1862-1868.
[37] M. Chu, Y. Shao, J. Peng, X. Dai, H. Li, Q. Wu and D. Shi, Biomaterials, 2013, 34, 4078-4088.
[38] H. Chen, J. Burnett, F. Zhang, J. Zhang, H. Paholak and D. Sun, J. Mater. Chem. B, 2014, 2, 757-765.
[39] X. Zhou, W. Xu, Y. Wang, Q. Kuang, Y. Shi, L. Zhong, and Q. Zhang, J Phys Chem C, 2010, 114, 19607–19613
[40] H. Hu, Z. Wang, L. Pan, S. Zhao, and S. Zhu, J Phys Chem C, 2010, 114, 7738-7742.
[41] W. Shi, X. Liu, C. Wei, Z. J. Xu, S. S. Sim, L. Liu and C. Xu, Nanoscale, 2015, 7, 17249-17253.
[42] E. A. Genina, Y. I. Svenskaya, I. Y. Yanina, L. E. Dolotov, N. A. Navolokin, A. N. Bashkatov, G. S. Terentyuk, A. B. Bucharskaya, G. N. Maslyakova, D. A. Gorin, V. V. Tuchin and G. B. Sukhorukov, Biomed Opt Express, 2016, 7, 2082-2087.
[43] C. Kim, C. Favazza, and L. V. Wang, Chem Rev, 2010, 110, 2756–2782
[44] L. S. Lin, Z. X. Cong, J. B. Cao, K. M. Ke, Q. L. Peng, J. Gao, H. H.Yang, G. Liu, and X. Chen, ACS Nano, 2014, 8, 3876-3883
[45] J. Yu, W. Yin, X. Zheng, G. Tian, X. Zhang, T. Bao, X. Dong, Z. Wang, Z. Gu, X. Ma and Y. Zhao, Theranostics, 2015, 5, 931-945.
[46] I. A. Reyes, F. Patiño, M. U. Flores, J.Narayanan, H. Calderón, and T. Pandiyan, J Mex Chem Soc, 2013, 57, 96-104.
[47] G. Xi, B. Yue, J. Cao and J. Ye, Chemistry, 2011, 17, 5145-5154.
[48] J.-F. Guo, B. Ma, A. Yin, K. Fan and W.-L. Dai, Applied Catalysis B: Environmental, 2011, 101, 580-586.
[49] R. Chalasani and S. Vasudevan, ACS Nano, 2013, 7, 4093-4104
[50] Y. Wu, L. Zhou, X. Du and Y. Yang, International Journal of Heat and Mass Transfer, 2015, 82, 545-554.
[51] M. Zheng, P. Zhao, Z. Luo, P. Gong, C. Zheng, P. Zhang, C. Yue, D. Gao, Y. Ma and L. Cai, ACS Appl Mater Interfaces, 2014, 6, 6709-6716.
[52] H. H. Richardson, M. T. Carlson, P. J. Tandler, P. Hernandez, and A. O. Govorov, Nano Lett, 2009, 9, 1139-1146
[53] X. Huang, I. H. El-Sayed, W. Qian, and M. A. El-Sayed, J Am Chem Soc, 2006, 128, 2115-2120
[54] P. K. Jain, X. Huang, I. H. El-Sayed, and M. A. El-Sayed, Accounts of Chemical Research, 2008, 41, 1578-1586
[55] C. A. Orozco, C. Urban, M. W. Knight, A. S. Urban, O. Neumann, S. W. Bishnoi, S. Mukherjee, A.M. Goodman, H. Charron,T. Mitchell, M. Shea, R.Roy, S. Nanda, R.lSchiff, N. J. Halas, and A. Joshi, ACS Nano, 2014, 8, 6372-6381
[56] M. Fleischmann, P. J. Hendra and A.J. Mcquillan, Chem Phys Lett, 974, 26, 163–166.
[57] D. L. Jeanmaire and R. P. V. Duyne, J Electroanal Chem, 1977, 84, 1–20
[58] H. Xu, J. Aizpurua, M. Ka and P. Apell, Phys Rev E, 2000, 62, 4318(7)
[59] K. 1. Bantz, A. F. Meyer, N. J. Wittenberg, H. Im, O. Kurtulus, S. H. Lee, N. C. Lindquist, S. H. Oh and C. L. Haynes, Phys Chem Chem Phys, 2011, 13, 11551-11567.
[60] M. Shaban and A. R. Galaly, Sci Rep, 2016, 6, 25307.
[61] W. E. Doering and S. Nie, J Phys Chem B, 2002, 106, 311-317
[62] D. Y. Wu, L. B. Zhao, X. M. Liu, R. Huang, Y. F. Huang, B. Ren and Z. Q. Tian, Chem Commun (Camb), 2011, 47, 2520-2522.
[63] X. Zhang, Z. Yu, W. Ji, H. Sui, Q. Cong, X. Wang and B. Zhao, The Journal of Physical Chemistry C, 2015, 119, 22439-22444.
[64] M. Moskovits, Reviews of Modern Physics, 1985, 57, 783-826.
[65] F. J. Garcı´a-Vidal and J. B. Pendry, Phys Rev Lett, 1996, 77, 1163-1166
[66] G. Mie, Ann Phys, 1908, 330, 377–445.
[67] B. J. Messinger, K. U. von Raben, R. K. Chang and P. W. Barber, Physical Review B, 1981, 24, 649-657.
[68] J. R. Lombardi and R. L. Birke, The Journal of Physical Chemistry C, 2014, 118, 11120-11130.
[69] A. D. McFarland, M. A. Young, J. A. Dieringer, and R. P. V. Duyne, J Phys Chem B, 2005, 109, 11279−11285.
[70] Z. Liu, L. Bai, G. Zhao and Y. Liu, Beilstein J Nanotechnol, 2016, 7, 1028-1032.
[71] I. Alessandri, J Am Chem Soc, 2013, 135, 5541-5544.
[72] S. Hayashi, R. Koh, Y. Ichiyama, and K. Yamamoto, Phys Rev Lett, 1988, 60, 1085–1088
[73] S. K. Islam, M. Tamargo, R. Moug and J. R. Lombardi, The Journal of Physical Chemistry C, 2013, 117, 23372-23377.
[74] X. X. Han, W. Ji, B. Zhao and Y. Ozaki, Nanoscale, 2017, 9, 4847-4861.
[75] J. R. Lombardi and R. L. Birke, Acc Chem Res, 2009, 42, 734–742
[76] X. Wang, W. Shi, G. She and L. Mu, Phys Chem Chem Phys, 2012, 14, 5891-5901.
[77] L. Jiang, P. Yin, T. You, H. Wang, X. Lang, L. Guo and S. Yang, Chemphyschem, 2012, 13, 3932-3936.
[78] X. Ling, L. G. Moura, M. A. Pimenta and J. Zhang, The Journal of Physical Chemistry C, 2012, 116, 25112-25118.
[79] L. G. Quagliano, J Am Chem Soc, 2004, 126, 7393–7398
[80] C. B. Mou, T. J. He, X. Y. Wang, F. Z. Liu, J. S. Jiang, L. W. Chen, Acta Phys Chim Sin, 1996, 12, 841–844
[81] P. Zhang, Y. Wang, T. He, B. Zhang, X. Wang, H. Xin and F.-t. Liu’, Chem Phys Lett, 1988, 153, 215–222
[82] X. Fu, F. Bei, X. Wang, X. Yang and L. Lu, Materials Letters, 2009, 63, 185-187.
[83] J. S. Teguh, F. Liu, B. Xing and E. K. Yeow, Chem Asian J, 2012, 7, 975-981.
[84] X. Xue, W. Ji, Z. Mao, H. Mao, Y. Wang, X. Wang, W. Ruan, B. Zhao and J. R. Lombardi, The Journal of Physical Chemistry C, 2012, 116, 8792-8797.
[85] S. J. Hurst, H. C. Fry, D. J. Gosztola, and T. Rajh, J Phys Chem C, 2011, 115, 620–630
[86] Q. Liu, L. Jiang and L. Guo, Small, 2014, 10, 48-51.
[87] A. Kudelski, W. Grochala, M. Janik-Czachor, Bukowska, A. Szummer and M. Dolata, J Raman Spectrosc, 1998, 29, 431–435
[88] O. Blajiev, H. Terryn, A. Hubin, L. Soukupova and P. Geerlings, Journal of Raman Spectroscopy, 2006, 37, 777-788.
[89] C. Mou, D. Chen, X. Wang, B. Zhang, T. He, H. Xin and F. Chen, Spectrochim Acta Part A, 1991, 47, 1575–1581.
[90] Y. Wang, Z. Sun, Y. Wang, H. Hu, B. Zhao, W. Xu and J. R. Lombardi, Spectrochim Acta A Mol Biomol Spectrosc, 2007, 66, 1199-1203.
[91] Y. Wang, Z. Sun, H. Hu, S. Jing, B. Zhao, W. Xu, C. Zhao and J. R. Lombardi, Journal of Raman Spectroscopy, 2007, 38, 34-38.
[92] X. Fu, Y. Pan, X. Wang and J. R. Lombardi, J Chem Phys, 2011, 134, 024707.
[93] X. Fu, T. Jiang, Q. Zhao and H. Yin, Journal of Raman Spectroscopy, 2012, 43, 1191-1195.
[94] D. Qi, L. Lu, L. Wang and J. Zhang, J Am Chem Soc, 2014, 136, 9886-9889.
[95] I. Alessandri and L. E. Depero, Small, 2014, 10, 1294-1298.
[96] W. Ji, W. Song, I. Tanabe, Y. Wang, B. Zhao and Y. Ozaki, Chem Commun (Camb), 2015, 51, 7641-7644.
[97] W. Ji, Y. Wang, I. Tanabe, X. Han, B. Zhao and Y. Ozaki, Chem. Sci., 2015, 6, 342-348.
[98] L. Yang, Xin Jiang, W. Ruan, J. Yang, B. Zhao, W. Xu, and J. R. Lombardi, J Phys Chem C, 2014, 118, 11120–11130.
[99] A. M. Goodman, Y. Cao, C. Urban, O. Neumann, C. Ayala-Orozco, M. W. Knight, A. Joshi, P.r Nordlander, and N. J. Halas, ACS Nano, 2014, 8, 3222–3231
[100] M. I. Darab and S. A. Shivashankar, RSC Adv, 2014, 4, 4105–4113
[101] G. Thomas, F. Demoisson, R. Chassagnon, E. Popova and N. Millot, Nanotechnology, 2016, 27, 135604.
[102] S. K. Park, N. S Lee, and S. H. Lee, Bull Korean Chem Soc, 2000, 21, 959－968