In this study, BT@ZnO:Yb heterostructures prepared using the combined sol-gel-hydrothermal methods were coated with chitosan (Qo) to obtain a hybrid heterostructure [BT@ZnO:Yb]-Qo. The structure, particle morphology, luminescence properties, and cytotoxicity of the hybrid heterostructure are discussed. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infra-red (FT-IR) as well as Raman and photoluminescence spectra, were used for characterisation and monitoring of the heterostructure formation process. The results reveal the formation of the BT@ZnO:Yb heterostructure, and are consistent with the relative intensities and positions of peaks in the XRD spectra of BT and ZnO:Yb, with the average particle size of similar to 75 nm. Effective Qo coating was achieved and a narrow, well-defined, and high-intensity luminescence signal was detected at similar to 610 nm for all the analysed samples. In vitro studies suggested that treatment with 1 mu g/ml BT@ZnO:Yb 3 mol% induced very low cytotoxicity on HeLa cells.