The development of new materials has brought about a change in the world since the era of bronze and iron. The evolution of stainless steel, concrete, and silicon redefined new boundaries and made modern era possible. It would not be a hyperbole if the present age is termed as the age of nanomaterials. Nanomaterials can be categorized in various types based on their shape and structure such as 0D (quantum dots (QDs)), 1D (nanorods, nanotubes), 2D (nanosheets), and 3D (flower like, cubical etc.).Molybdenum disulfide (MoS 2 ), a typical layered 2D transition metal dichalcogenide, has received colossal interest in the past few years due to its unique structural, physicochemical, optical, and biological properties. While MoS 2 is mostly applied in traditional industries such as dry lubricants, intercalation agents, and negative electrode material in lithium-ion batteries, its 2D and 0D forms have led to diverse applications in sensing, catalysis, therapy, and imaging. Herein, a systematic overview of the progress that is made in the field of MoS 2 research with an emphasis on its different biomedical applications is presented. This article provides a general discussion on the basic structure and property of MoS 2 and gives a detailed description of its different morphologies that are synthesized so far, namely, nanosheets, nanotubes, and quantum dots along with synthesis strategies. The biomedical applications of MoS 2 -based nanocomposites are also described in detail and categorically, such as in varied therapeutic and diagnostic modalities like drug delivery, gene delivery, phototherapy, combined therapy, bioimaging, theranostics, and biosensing. Finally, a brief commentary on the current challenges and limitations being faced is provided, along with a discussion of some future perspectives for the overall improvement of MoS 2 -based nanocomposites as a potential nanomedicine. 2D MoS 2 -Based Nanomaterials www.advancedsciencenews.com

Two-dimensional molybdenum disulfide (MoS2) based nanosheets functionalized or loaded with an antimicrobial agent have recently attracted attention as highly efficient antibacterial agent. MoS2 sheets act as the photothermal transducers in inducing bacterial cell death on impingement of NIR radiation or enabled cell inactivation by wrapping around the cells. However, the intrinsic ability of MoS2 to act as an effective antibacterial agent without the use of any external stimuli or antimicrobial agent is still not well explored. This study provides a detailed mechanism of antibacterial action of chitosan exfoliated MoS2 nanosheets (CS-MoS2) by deciphering the key events happening both at the membrane surface and inside the bacteria as a result of interaction of bacterial cells with the nanosheets. A simple, green, one-step process was employed for synthesizing stable and positively charged MoS2 nanosheets. The prepared nanosheets showed excellent bactericidal activity against both Gram-positive (MIC = 90 μg/mL, MBC = 120 μg/mL) and Gram-negative bacteria (MIC = 30 μg/mL, MBC = 60 μg/mL). Investigations into deciphering the mechanism of action revealed that the CS-MoS2 nanosheets interacted strongly with the bacterial cells through electrostatic interactions and caused rapid depolarization of the membranes through dent formations. On account of strong van der Waals and electrostatic forces occurring between the CS-MoS2 nanosheets and membrane phospholipid molecules, deepening of dents occurred, which resulted in complete membrane disruption and leakage of cytoplasmic contents. This led to inactivation of the bacterial respiratory pathway through inhibition of dehydrogenase enzymes and induced metabolic arrest in the cells. Simultaneously, disruption of the antioxidant defense system of the cells by increased levels of intracellular ROS subjected the cells to oxidative damage and added to the overall bactericidal action. The nanosheets also displayed antibiofilm properties and were found to be compatible with mammalian cells even at high concentrations.

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Generally, mandibular first molars have one mesial and distal root but in few cases there are morphological variations where in the number of roots and root canals may vary. Radix Entomolaris (RE) is the presence of an additional lingual root distally in mandibular molars. Correct diagnosis is important before starting with endodontic therapy in these teeth to ensure successful treatment outcome. This case report series describes the endodontic management of mandibular first molar with radix entamolaris.