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. 2024 Jan 21;8(2):150-162.
doi: 10.7150/ntno.87536. eCollection 2024.

Biodegradable Nanocomposite of ZnS(Mn) Quantum Dots Immobilized Graphene Oxide for Bioimaging Applications

Pavithra Kurungottu  1 , Midhun Ben Thomas  2 , Mahesh M Lalitha  1 , Prathiksha Ganesh  1 , Divya Prakash Gnanadhas  3   4 , Dipshika Chakravortty  3 , Ashok M Raichur  2 , Rajendra Kurapati  1
Affiliations

Biodegradable Nanocomposite of ZnS(Mn) Quantum Dots Immobilized Graphene Oxide for Bioimaging Applications

Pavithra Kurungottu et al. Nanotheranostics. .

Abstract

Developing a biocompatible and biodegradable graphene-based fluorescent nanoprobe with the ability to visualize live cells could be interesting for intracellular imaging and monitoring the efficiency of chemotherapy. Herein, we report a biodegradable and biocompatible hybrid fluorescent graphene oxide (GO)-ZnS(Mn) composite synthesized via in situ growth of ZnS(Mn) quantum dots (QDs) on the surface of GO in the aqueous medium. The prepared 'GO-ZnS(Mn)' composite was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and high-resolution transmission electron microscopy (HR-TEM) along with selected area electron diffraction (SAED). Further, the fluorescence properties of the GO-ZnS(Mn) composite were studied using fluorescence emission spectroscopy. The composite material exhibited a strong and broad visible light fluorescence from 500 to 600 nm by excitation with 365 nm (UV) light. The cytotoxic experiments of folic acid (FA) conjugated GO-ZnS(Mn) using MTT [(3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide)] assay revealed that the composite had excellent biocompatibility even at higher concentrations up to 200 µg/mL in HeLa cell lines. Next, the bioimaging experiments carried out using confocal fluorescence laser scanning microscopy (CLSM) revealed that GO-ZnS(Mn) composite was taken up by the HeLa cells effectively within 12 h of incubation via receptor (folate) mediated endocytosis with strong fluorescence throughout the cell surface. Finally, the biodegradability of GO-ZnS(Mn) composite was studied by treating it with human myeloperoxidase enzyme (hMPO) isolated from the primary immune cells, neutrophils, which is important to understand the in vivo fate of GO-Zns(Mn). The HR-TEM and Raman analyses confirmed the biodegradation of GO-ZnS(Mn) within 15 h of hMPO treatment. Thus, the biodegradable GO-ZnS (Mn) composite could be helpful for chemotherapy and bioimaging applications.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interest exists.

Figures

Scheme 1
Scheme 1
Illustration of synthesis procedure for FA conjugated GO-ZnS(Mn) composite, specific cellular uptake, and bioimaging using the fluorescence of GO-ZnS(Mn) composite.
Figure 1
Figure 1
(A) FT-IR spectra of GO-ZnS(Mn), FA-GO-ZnS(Mn), and FA alone; and (B) UV-vis spectrum (a) and the fluorescence spectrum (b) of GO-ZnS(Mn) composite, respectively.
Figure 2
Figure 2
Digital photos of (A) the GO aqueous suspension, (B) aqueous ZnS(Mn) alone, (C) composite of GO-ZnS(Mn) and (D) aqueous GO-ZnS(Mn) composite under UV light exposure at a wavelength of 365 nm, respectively.
Figure 3
Figure 3
HR-TEM images of GO-ZnS(Mn) at low and high magnification shown in A and B, respectively, (C) represents the SAED pattern of the GO-ZnS(Mn) composite, (D) HR-TEM image of ZnS(Mn) particles alone without immobilization on the GO.
Figure 4
Figure 4
Shows the XRD patterns of GO (A), GO-ZnS(Mn) (B) and ZnS(Mn) (C), respectively.
Figure 5
Figure 5
Shows (A) TGA curves of GO, ZnS(Mn) QDs and GO-ZnS(Mn) composite and (B) the Raman spectrum of GO-ZnS(Mn) and GO, respectively.
Figure 6
Figure 6
(A) Shows the survey spectrum of GO-ZnS(Mn), and core level XPS spectra of (B) Zn 2p (C) S 2P (D) Mn 2p3/2 (E) C 1s and (F) O 1s in GO-ZnS(Mn) composite, respectively.
Figure 7
Figure 7
Cell viability assay for cytotoxicity values versus incubation concentration started from 1 µg/mL to 1000 µg/mL of GO-ZnS(Mn) composite in HeLa cells for 12 h.
Figure 8
Figure 8
Cellular uptake and bioimaging studies with FA conjugated GO-ZnS(Mn) composite treated with HeLa cells, where the first column shows DAPI stained nuclei, the second column shows green photoluminescence exhibited by the ZnS(Mn) NPs immobilized on the surface of GO, third and fourth column shows the merged and bright field images respectively.
Figure 9
Figure 9
Fluorescent imaging of the HeLa cells after incubating with GO-ZnS(Mn) alone for 12 h without staining the nuclei with the DAPI.
Figure 10
Figure 10
TEM images and SAED pattern of GO-ZnS(Mn) with hMPO+H2O2 (A-C) and GO-ZnS(Mn) with H2O2 alone (D-F) after treating for 15 h, respectively.
Figure 11
Figure 11
The Raman spectra of GO-ZnS(Mn) composite after treating with hMPO+H2O2 for 0 and 15 h, respectively, where each spectrum is an average of a minimum of five individual spectra.
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References

    1. Li J, Pant A, Chin CF, Ang WH, Ménard-Moyon C, Nayak TR. et al. In vivo biodistribution of platinum-based drugs encapsulated into multi-walled carbon nanotubes. Nanomedicine: NBM. 2014;10:1465–75. - PubMed
    1. Kurapati R, Martìn C, Palermo V, Nishina Y, Bianco A. Biodegradation of graphene materials catalyzed by human eosinophil peroxidase. Faraday Discuss. 2021;227:189–203. - PubMed
    1. Ma B, Martín C, Kurapati R, Bianco A. Degradation-by-design: how chemical functionalization enhances the biodegradability and safety of 2D materials. Chem Soc Rev. 2020;49:6224–47. - PubMed
    1. Chung C, Kim Y-K, Shin D, Ryoo S-R, Hong BH, Min D-H. Biomedical Applications of Graphene and Graphene Oxide. Acc Chem Res. 2013;46:2211–24. - PubMed
    1. Pan Y, Sahoo NG, Li L. The application of graphene oxide in drug delivery. Expert Opin Drug Del. 2012;9:1365–76. - PubMed

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