Havan, also known as Homam or yagna, is a traditional Hindu ritual that involves the ceremonial burning of various substances, ghee, mango wood, sandal wood, herbs like tulsi, basil, neem leaves, and other aromatic herbs, rice grains and fragrant substances like benzoin and frankincense, in a fire pit [1]. The combustion of a mixture of natural materials, including aromatic plants, resins, wood, and other organic substances including sandalwood, frankincense, sage, palo santo, and various medicinal herbs, results in Havan smoke [2]. Havan smoke, is also known as sacred smoke or ritual smoke. This Havan smoke holds significant cultural and spiritual importance in many ancient traditions and religious practices. The smoke generated during these rituals contains a complex mixture of volatile organic compounds (VOCs), aromatic molecules, and other chemical constituents. While primarily performed for religious purposes, recent research has explored the potential antimicrobial properties of the smoke generated during havan ceremonies [3].
Moreover, the burning of certain plant materials in havan rituals has been found to release bioactive compounds into the air, which can have potential therapeutic benefits. Carbon nanodots have recently risen to the position where they hold immense promise in biomedicine. Their small size, excellent biocompatibility, and low toxicity make them suitable for various biomedical applications such as drug delivery, bioimaging, and therapeutics [4]. CNDs can be functionalized with biomolecules, enabling targeted drug delivery and imaging of specific cells or tissues.[5] They can also serve as efficient carriers for therapeutic agents, including genes and proteins. CNDs have been isolated from smoke and their role in the medicinal properties of medicinal smoke has been deliberated and confirmed [6].
CNDs exhibit potent antibacterial effects against various oral bacteria, including common pathogens such as Streptococcus mutans, Porphyromonas gingivalis, and Actinomyces naeslundii [7]. These bacteria are known to be associated with dental caries, periodontal diseases [8], and other oral infections. CNDs can interact with bacterial cell membranes, leading to their disruption and subsequent cell death [9]. The small size and unique surface chemistry of CNDs facilitate their penetration into bacterial cells, where they can interfere with essential cellular processes and structures. CNDs can induce oxidative stress in oral bacteria, leading to the generation of reactive oxygen species (ROS) within bacterial cells [10]. Elevated ROS levels can cause damage to cellular components, including proteins, DNA, and lipids, ultimately impairing bacterial growth and survival [11]. One advantage of using CNDs against oral bacteria is their biocompatibility and low toxicity. Studies have indicated that CNDs exhibit minimal cytotoxicity towards mammalian cells, making them potentially safe for oral healthcare applications [12].
Coliform bacteria, including Escherichia coli (E. coli), are a common group of microorganisms found in the intestines of humans and animals [13]. While most strains are harmless, some can cause severe gastrointestinal illnesses and urinary tract infections [14]. The prevalence of anti-coliform bacteria in the environment, along with the emergence of antibiotic-resistant strains, has raised concerns regarding public health and the need for alternative approaches to combat these pathogens. The smoke generated during havan ceremonies contains a complex mixture of volatile organic compounds (VOCs), such as [15] polyphenols, terpenes, and other bioactive compounds derived from the burning substances. These compounds have been recognized in scientific literature for their antimicrobial properties against a wide range of pathogens. that certain VOCs present in smoke, such as phenolic compounds, can exhibit antimicrobial effects by disrupting the cell membranes and inhibiting bacterial growth [16].
CNDs can interact with the biofilm matrix, which is primarily composed of polysaccharides, proteins, and extracellular DNA. The unique size and surface properties of CNDs allow them to penetrate the biofilm matrix and disrupt its structure, weakening the biofilm's integrity. CNDs have been found to inhibit the initial formation of biofilms by preventing bacterial adhesion to surfaces. They can penetrate bacterial cells, disrupt cellular processes, and induce cell death, thereby targeting the bacteria within the biofilm. CNDs can be used as carriers for antimicrobial agents, delivering them directly to the biofilm and increasing their efficacy.
The objective of the present study is to extract the carbon nanodots from the Havan smoke and characterize the nanomaterial. Further, the key objective behind isolating this nanomaterial is to obtain an eco-friendly nanomaterial that could exhibit bactericidal activity against coliforms such as E. coli and Enterobacter faecalis as well as oral bacteria. The anti- biofilm effect of these Havan smoke-derived carbon nanodots-initiated coatings was also evaluated.