Green synthesis of ZnS quantum dot/biopolymer photoluminescent nanoprobes for bioimaging brain cancer cells

• Published in: Materials chemistry and physics 2020-04, Vol.244, p.122716, Article 122716
• Main Authors: Caires, Anderson J., Mansur, Alexandra A.P., Carvalho, Isadora C., Carvalho, Sandhra M., Mansur, Herman S.
• Format: Article
• Language: English
• Subjects: Biocompatibility; Biopolymers; Blue shift; Brain cancer; Cancer; Cancer bioimaging; Colloiding; Fluorescence; Fluorescent nanoprobes; Green nanotechnology; Luminescent nanoconjugates; Luminescent nanomaterials; Medical imaging; Nanomaterials; Optical properties; Photoluminescence; Photon correlation spectroscopy; Precursors; Quantum dots; Spectrum analysis; Synthesis; Toxicity; Zeta potential; Zinc sulfide; ZnS quantum dots
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2020.122716

Semiconductor quantum dots (QDs) are one of the most interesting photoluminescent nanomaterials with very promising applications in cancer nanomedicine. In this work, ZnS fluorescent quantum dots (ZnS-QDs) were synthesized and stabilized by carboxymethylcellulose (CMC) as a pH-sensitive biopolymer using a facile one-step green aqueous colloidal process at distinct pH conditions (acidic, neutral and alkaline) and chemical proportions of precursors (Zn2+, S2−). The optical properties of these nanoconjugates (ZnS@CMC) were characterized by UV–visible and photoluminescence spectroscopy. The morphological features and physicochemical properties were evaluated by TEM, FTIR spectroscopy, zeta potential, and dynamic light scattering (DLS) analyses. The cytocompatibility in vitro of ZnS@CMC was assessed by MTT assay using normal and malignant glioma cells. The UV–Vis results indicated that ZnS-QDs were effectively produced with different bandgap energies (from 4.5 to 3.8 eV) blue-shifted from bulk (Ebulk = 3.61 eV), and sizes (typically from 3.3 to 4.5 nm), dependent on the pH and concentration ratio of precursors during the synthesis. Analogously, the changes of synthesis parameters significantly altered the photoluminescence emission energies and intensities within the visible range of spectra (PL maxima from λ = 400–430 nm, at pH = 3.5, [Zn:S] ratio = 1:2). The cell viability results in vitro (>90%) demonstrated no cytotoxicity of ZnS@CMC nanohybrids towards both cell types. Importantly, these ZnS@CMC nanoconjugates behaved as active fluorescent nanoprobes for bioimaging malignant glioma cells proving the high potential for applications in cancer nanomedicine. [Display omitted] •Facile green synthesis of ZnS quantum dot-carboxymethylcellulose nanoconjugates. (79).•CMC pH-sensitive ligand tailored nucleation/growth processes of ZnS nanocrystals. (80).•Colloidal process parameters regulated the optical properties of ZnS@CMC nanohybrids. (84).•ZnS@CMC colloids behaved as active photoluminescent biological nanoprobes. (73).•Fluorescent nanoconjugates were effective for bioimaging brain cancer cells in vitro. (84).