1 hexadecyl trimethyl ammonium bromide

All chemicals were used without purification. The ammonium hydroxide solution (NH₄OH in H₂O, 30–33%), methanol (CH₃OH, 99.99%), and tetraethyl orthosilicate (TEOS, 99.99%) were obtained from Sigma‐Aldrich (Saint Louis, MO, US). Ethanol (C₂H₅OH, 99.8%) was purchased from Thermo Fisher Chemical (Waltham, Massachusetts, US). (1‐Hexadecyl) trimethyl ammonium bromide (CTAB, 98%), zinc acetate (Zn(CH₃COO)₂, 99.98%), tin(II) chloride (99%), and chromium(III) nitrate nonahydrate (Cr(NO₃)₃·9H₂O, 98.5%) were obtained from Alfa Aesar (Haverhill, MA,USA). Gallium oxide (Ga₂O₃, 99.99%) was procured from Gredmann. Nitric acid (HNO₃, 69–70%) was from J. T. Baker (Phillipsburg, NJ, USA). The Keratinocyte Serum‐Free Growth (K‐SFM) and Roswell Park Memorial Institute (RPMI 1640) media were purchased from Thermo Fisher Scientific (Waltham, Massachusetts, US) for cell seeding. The Beas2B normal lung bronchus cells used K‐SFM medium, and A549 and CL1‐5 lung cancer cells were incubated in RPMI 1640 medium. The penicillin–streptomycin–glutamine (PSG) supplement for culture media was purchased from GIBCO (Waltham, MA, USA).

Copper (II) chloride dehydrate (Riedel-de Haën, USA), Iron(II) chloride anhydrous(Alfa Aesar, USA), Hydrogen tetrachloroaurate(III) hydrate(Alfa Aesar, USA), (1-Hexadecyl) trimethylammonium bromide(Alfa Aesar, USA), Hydrazine hydrate(Acros Organics, USA), Poly(styrene-alt-maleic acid) sodium salt solution (PSMA)(Aldrich, USA), L-Ascorbic acid(Sigma-Aldrich, USA), Hydrogen peroxide solution(Sigma, USA), p-Toluenesulfonic Acid, 12% in Acetic Acid (TA) (Acros Organics, USA), N, N-Dimethyl-4-nitrosoaniline (RNO) (Alfa Aesar, USA).

Gold(iii) chloride hydrate (99.995%), cysteamine (∼95%), l-ascorbic acid (reagent grade), silver nitrate (99.9999%), sodium borohydrate (99%) and trisodium citrate dihydrate were purchased from Sigma Aldrich. (1-Hexadecyl)trimethylammonium bromide (98%) were purchased from Alfa Aesar.
To characterize the synthesized AuNPs, dynamic light scattering (Zetasizer Nano ZSP, Malvern Panalytical) was used to measure the zeta potential and hydrodynamic radius. UV-vis spectra were measured using a spectrophotometer (Biowave II, WPA) and a fluorometer plate reader (Infinite M200 PRO, Tecan). Images of the well plates were taken using a commercially available CCD camera (Lumix DC-TZ91, Panasonic).