6‐Mercaptopurine‐Induced Fluorescence Quenching of Monolayer MoS₂ Nanodots: Applications to Glutathione Sensing, Cellular Imaging, and Glutathione‐Stimulated Drug Delivery

Abstract

Molybdenum disulfide (MoS 2 ) nanodots (NDs) with sulfur vacancies have been demonstrated to be suitable to conjugate thiolated molecules. However, thiol-induced fluorescence quenching of MoS 2 NDs has been rarely explored. In this study, 6-mercaptopurine (6-MP) serves as an efficient quencher for the fluorescence of monolayer MoS 2 (M-MoS 2 ) NDs. 6-MP molecules are chemically adsorbed at the sulfur vacancy sites of the M-MoS 2 NDs. The formed complexes trigger the efficient fluorescence quenching of the M-MoS 2 NDs due to acceptor-excited photoinduced electron transfer. The presence of glutathione (GSH) efficiently triggers the release of 6-MP from the M-MoS 2 NDs, thereby switching on the fluorescence of the M-MoS 2 NDs. Thus, the 6-MP-M-MoS 2 NDs are implemented as a platform for the sensitive and selective detection of GSH in erythrocytes and live cells. Additionally, thiolated doxorubicin (DOX-SH)-loaded M-MoS 2 NDs (DOX-SH/M-MoS 2 NDs) serve as GSH-responsive nanocarriers for DOX-SH delivery. In vitro studies reveal that the DOX-SH/M-MoS 2 NDs exhibit efficient uptake by HeLa cells and greater cytotoxicity than free DOX-SH and DOX. In vivo study shows that GSH is capable of triggering the release of DOX-SH from M-MoS 2 ND-based nanomaterials in mice. It is revealed that the DOX-SH/M-MoS 2 NDs can be implemented for simultaneous drug delivery and fluorescence imaging.

Functionalized MoS2 Nanovehicle with Near‐Infrared Laser‐Mediated Nitric Oxide Release and Photothermal Activities for Advanced Bacteria‐Infected Wound Therapy

“…Evaluation of GSH Oxidation : The changes in GSH concentration were assessed using were assessed using Ellman's experiments . Typically, 225 µL of MoS 2 ‐α‐CD nanosheets (150 µg mL −1 ) dispersed in bicarbonate buffer solution (50 × 10 −3 m , pH = 8.7) were mixed well with 1.0 × 10 −3 m GSH bicarbonate buffer solution (225 µL) and incubated for 30, 60, 90, and 120 min with mixing at 180 rpm at 25 and 50 °C in the dark.…”

“…Based on the antibacterial potential of NO and the design requirements of controlled‐release NO nanovehicles, we envisaged that combination of a distinctive NIR laser‐mediated NO donor with PTT could achieve promising antibacterial effects. In particular, nano‐sized molybdenum sulfide (MoS 2 ), one of the new rising 2D transition metal dichalcogenides (TMDs), is being investigated for biomedical applications, particularly as a nanocarrier and photothermal nanoagent, owing to its advantages such as large surface area, easy surface modification, and high NIR photothermal conversion property . To date, although there are some concerns related to antibacterial applications of MoS 2 , utilizing the high NIR photothermal effect and unique surface characteristics of MoS 2 for constructing highly effective antibacterial platforms is still in its infancy .…”

2D MoS2‐Based Nanomaterials for Therapeutic, Bioimaging, and Biosensing Applications

“…As a result, the MoS 2 @PANI‐PEG nanohybrids demonstrated highly efficient in vitro and in vivo bimodal imaging guided combined PTT‐radiotherapy of tumors. In another study, monolayer MoS 2 nanodots (M‐MoS 2 NDs) were synthesized and loaded with thiolated DOX, which served as an intracellular glutathione‐responsive drug delivery system . The drug‐loaded nanodots were readily taken up by HeLa cells in culture and showed enhanced cytotoxicity as compared to free DOX.…”

Boosting heterojunction interaction in electrochemical construction of MoS2 quantum dots@TiO2 nanotube arrays for highly effective photoelectrochemical performance and electrocatalytic hydrogen evolution

“…Thus, constructing MoS2 nanodots are a promising strategy to enhance the efficiency of hydrogen evolution reaction (HER). Previous reports of MoS2 QDs include sonication and hydrothermal treatment [9], liquid exfoliation [10] and ball milling with chemical Li-intercalation [11], however, these synthetic approaches are sensitive to the conditions and are limited by time consumption, harsh environments and toxic organic solvents. Usually, MoS2 nanodots are supported on Au foil, Pt piece and other conductive substrates to carry out the hydrogen evolution reaction [12].…”