The synthesis of D/[email protected] was shown in Scheme 1. First, a one-pot seedless-mediated growth method was adopted to synthesize CTAB-stabilized AuNRs. Transmission electron microscopy (TEM) images show that the AuNRs are about 25 nm in length and 8 nm in width [Fig. 1(a)] and longitudinal surface plasmon resonance (LSPR) peak of 730 nm [Fig. 1(d)]. Then, a mesoporous silica shell layer coating on the surface of the AuNRs by the sol–gel method is observed, and the thickness of the silica shell is about 20 nm [Fig. 1(b)]. After coating, the LSPR peak was found to shift to 757 nm due to the surface refractive index changes [Fig. 1(d)]. The anticancer drug DOX was loaded into the pores of the [email protected] by diffusing prior to the PDA deposition. Subsequently, the [email protected] was incubated with dopamine hydrochloride in Tris-HCl (pH 8.5, 10 mM) solution to form polydopamine layer. After coating with PDA, a block layer on the surface of the [email protected] can be observed [Fig. 1(c)], and the peak of the LSPR has a further red shift to 783 nm [Fig. 1(d)]. The hydrodynamic diameter of the [email protected] is about 40 nm (Fig. S1). The loading of another anticancer drug Btz on the [email protected] was conducted through the conjugation between boronic acid of Btz and catechol of PDA.Each modification of the AuNRs is confirmed by FT-IR, zeta potential, and N2 absorption–adsorption. FT-IR spectrum of [email protected] shows the characteristic C–H stretching vibrations at 2922 and 2856 cm−1 and C–H deformation vibration around 1480 cm−1.3535. J. Wang, H. Liu, F. Leng, L. Zheng, J. Yang, W. Wang, and C. Z. Huang, “ Autofluorescent and pH-responsive mesoporous silica for cancer-targeted and controlled drug release,” Microporous Mesoporous Mater. 186, 187–193 (2014). https://doi.org/10.1016/j.micromeso.2013.11.006 These C–H peaks disappear after removing CTAB. Compared to [email protected], [email protected] displays an absorption band of 1290 cm−1, which is assigned to the stretching vibration of C–O and primary amine vibration from PDA, which indicates the PDA layer is successfully coated on the surface of the [email protected] (Fig. S2).3636. R. Zheng, S. Wang, Y. Tian, X. Jiang, D. Fu, S. Shen, and W. Yang, “ Polydopamine-coated magnetic composite particles with an enhanced photothermal effect,” ACS Appl. Mater. Interfaces 7(29), 15876–15884 (2015). https://doi.org/10.1021/acsami.5b03201 Due to the existence of the CTAB, the AuNRs and [email protected] exhibit a zeta potential of +23.3 and +22.2 mV, respectively. After removing the template of CTAB, the potential of [email protected] has a negative value of −14.5 mV. Moreover, after the [email protected] are coated with the PDA shell, the potential of the obtained nanoparticles is still −15.0 mV because of the catechol groups on the surface of the [email protected] nanoparticles [Fig. 1(e)].3636. R. Zheng, S. Wang, Y. Tian, X. Jiang, D. Fu, S. Shen, and W. Yang, “ Polydopamine-coated magnetic composite particles with an enhanced photothermal effect,” ACS Appl. Mater. Interfaces 7(29), 15876–15884 (2015). https://doi.org/10.1021/acsami.5b03201 Figures 1(f) and 1(g) show the nitrogen adsorption–desorption isotherms and the pore size distribution diagram of the prepared [email protected] and [email protected] nanoparticles. For the [email protected], the BET surface area is 564.76 m2 g−1, the pore volume is 0.82 cm3 g−1, and the pore size is about 2.33 nm. After depositing the PDA shell, the BET specific surface area, pore size, and pore volume of the [email protected] nanoparticles are smaller than the [email protected] nanoparticles and are 62.35 m2 g−1, 1.89 nm, and 0.2 cm3 g−1, respectively. This further suggests that the PDA shell has been successfully modified on the surface of the [email protected] nanoparticles.