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The rapid and reliable detection of triethylamine (TEA), a toxic, explosive, volatile organic compound at room temperature, is highly significant for food safety, environmental, and human health monitoring. This manuscript reports a layered molybdenum disulfide (MoS2) nanosheet-coated polypyrrole (PPy) nanorod-based heterostructure sensor (MsPy) which offers superior sensing properties toward TEA at room temperature (25 °C). Herein, different MsPy nanocomposites were synthesized, followed by a controlled sulfidation reaction through dissolution, diffusion, and regrowth mechanisms. Optimizing the ratio of the precursor of molybdenum trioxide (MoO3/PPy) is crucial for achieving effective deposition of a layered MoS2nanosheet on the PPy surface. The as-prepared MoS2nanosheet-coated PPy sensor (MsPy_40) enables one to selectively detect trace TEA vapor at 25 °C with a detection lower limit of 0.5 ppm. The MsPy_40 sensor exhibits 17 times higher response than the pristine MoS2nanosheet to 50 ppm TEA, with rapid response (∼3.9 s) and recovery (∼19.6 s), along with better stability, good selectivity, and remarkable repeatability. The significantly enhanced sensing performance is attributed to the unique surface morphology of the layered MoS2nanosheet-coated PPy nanorod and the formation of a p–n heterojunction between PPy and MoS2.

Nanotechnology has acquired an immense recognition in cancer theranostics. Considerable progress has been made in the development of targeted drug delivery system for potent delivery of anticancer drugs to tumor-specific sites. Recently, multifunctional nanomaterials have been explored and used as nanovehicles to carry drug molecules with enhanced therapeutic efficacy. In this present work, graphene oxide quantum dot (GOQD) was conjugated with folic acid functionalized chitosan (FA-CH) to develop a nanocargo (FA-CH-GOQD) for drug delivery in cancer therapy. The synthesized nanomaterials were characterized using Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, scanning electron microscopy, transmission electron microscopy, and dynamic light scattering. Photoluminescence spectroscopy was also employed to characterize the formation of GOQD. To validate the efficacy of FA-CH-GOQD as nanocarriers, doxorubicin (DOX) drug was chosen for encapsulation. The in vitro release pattern of DOX was examined in various pH ranges. The drug release rate in a tumor cell microenvironment at pH 5.5 was found higher than that under a physiological range of pH 6.5 and 7.4. An MTT assay was performed to understand the cytotoxic behavior of GOQD and FA-CH-GOQD/DOX. Cytomorphological micrographs of the A549 cell exhibited the various morphological arrangements subject to apoptosis of the cell. Cellular uptake studies manifested that FA-CH-GOQD could specifically transport DOX within a cancerous cell. Further anticancer efficacy of this nanomaterial was corroborated in a breast cancer cell line and demonstrated through 4′,6-diamidino-2-phenylindole dihydrochloride staining micrographs.