[3] Lane L A, Qian X, Nie S. Chem. Rev., 2015, 115(19): 10489.

[4] Jin H Y, Li D W, Zhang N, et al. ACS Appl. Mater. Interf., 2015, 7(22): 12249.

[5] Chaudhari K, Pradeep T. Sci. Rep., 2014, 4: 5948.

[6] Lee K, Cui Y, Lee L P, et al. Nat. Nanotech., 2014, 9(6): 474.

[7] Kang J W, So P T C, Dasari R R, et al. Nano. Lett., 2015, 15(3): 1766.

[9] Zhang Q, Lu X, Tang P, et al. Plasmonics, 2016: 1.

[10] Zhang Y, Walkenfort B, Yoon J H, et al. Phys. Chem. Chem. Phys., 2015, 17(33): 21120.

[11] Fang W, Wang Z, Zong S, et al. Biosens Bioelectron, 2014, 57: 10.

[12] Zheng X S, Hu P, Cui Y, et al. Anal. Chem., 2014, 86(24): 12250.

[13] Wei H, Willner M R, Marr L C, et al. Analyst, 2016.

[14] Kannadorai RK, Chiew GG Y, Luo K Q, et al. Cancer Lett., 2015, 357(1): 152.

[15] Jeyaraj M, Arun R, Sathishkumar G, et al. Mater Res. Bull., 2014, 52: 15.

[16] Wen Q, Zhang X, Cai J, et al. Analyst, 2014, 139(10): 2499.

[17] Chen W H, Luo G F, Xu X D, et al. Nanoscale, 2014, 6(16): 9531.

[18] Kang B, Austin L A, El-Sayed M A. ACS Nano, 2014, 8(5): 4883.

[19] Aioub M S, El-Sayed M A. J. Am. Chem. Soc., 2016, 138(4): 1258.

[20] Jiang J, Auchinvole C, Fisher K, et al. Nanoscale, 2014, 6(20): 12104.

[21] Han G, Liu R, Han M Y, et al. Anal. Chem., 2014, 86(23): 11503.

[22] Panikkanvalappil S R, Hira S M, Mahmoud M A, et al. J. Am. Chem. Soc., 2014, 136(45): 15961.

[23] Xiao L, Harihar S, Welch D R, et al. Anal. Chim. Acta, 2014, 843: 73.

[24] Gao L, Liu M, Ma G, et al. ACS Nano, 2015, 9(11): 10979.

[25] Prigodich A E, Randeria P S, Briley W E, et al. Anal. Chem., 2012, 84(4): 2062.

[26] Halo T L, McMahon K M, Angeloni N L, et al. Proc. Natl. Acad. Sci. USA, 2014, 111(48): 17104.

[27] Yang Y, Huang J, Yang X, et al. J. Am. Chem. Soc., 2015, 137(26): 8340.

[28] Yang Y, Huang J, Yang X, et al. Anal. Chem., 2016. 11.

[29] Banga R J, Chernyak N, Narayan S P, et al. J. Am. Chem. Soc., 2014, 136(28): 9866.