Lichen-Based Nano-Particles, an Emerging Antibacterial Approach

Bacterial pathogens produced resistance against the existing antimicrobial applications. Scientist trending towards the potent novel eco-friendly and cost effective antimicrobial approaches and fabricating bio-based nano-particles. In this regard, several bio-materials have been investigated, such as, bacteria, fungi, algae, lichens and green plants. Lichens are introduced as an emerging sour-ce to synthesis bio-based nano-particles. The lichen-based metal nano-mate-rials, especially fabricated by applying green chemistry strategies, have resulted significant alternates to traditional antimicrobial applications. Several studies break out and revealed that lichen-based nano-particle showed strong antimicrobial efficacy, as the lichens are biologically compatible. Current review summarizes an overview of lichen-based nano-materials, their fabrication, their applications, and their molecular action mechanism. As it emerged a broad spectrum antimicrobial agent for pharmaceutical and agricultural applications. nanocomposites with reduced lichen-reduced gra-phene oxide nanoparticles (LrGO) (LrGO-AgAu). The characterization of nanoparticles, so formed, was carried out using techniques such as TEM, scanning electron microscopy (SEM), XRD, and FT-IR.


Introduction
Antibiotic resistance is an ecosystem issue that threatens the health of humans, animals and the environment within the unified framework of "One Health". Resistant bacteria from one geographic area can spread to other parts of the world through direct exposure or through the food chain in a reservoir and environment [1]. However, recent advances in nanotechnology have led to the development of nanoparticles, which are considered effective broad-spectrum an-tibacterial agents [2]. Nanotechnology has been recently revolutionized in the scientific world, especially in the fields of industry, medicine, agriculture, and electronics [3]. The biosynthesis of nanoparticles using green synthesis methods involves the biological reduction of metals or metal element oxides to their basic elements. The shape is from 1 to 100 nm; therefore, the process has received a lot of attention due to its environmental friendliness and cost efficiency [4] [5]. Lichens are extensively studied for the production of green nanoparticles and as well as for the antibacterial efficiency [4]. Basically Lichens are the symbiotic association of fungi and algae. They have several biologically active compounds [6]. Many reports are available on the synthesis of nanoparticles from different types of lichens.
Recently Parmotrema pseudotinctorum and Ramalina hossei were used in combination of two kinds of extracts to synthesize the AgNPs against several grampositive and gram-negative bacteria that caused food poisoning [7]. The four gram-positive pathogens (Bacillus subtilis, Salmonella typhimurium, Staphylococcus epidermidis, and Methicillin-resistant Staphylococcus aureus) and four Gramnegative strains (Salmonella typhi, Proteus vulgaris, Pseudomonas aeruginosa, and Serratia marcescens) were inhibited by using Ag-NP synthesized from water extract of Ramalina dumeticola [8]. NP-Ag produced by four lichens, flounder (Parmeliopsis ambigua), fleshy dots (Punctelia subrudecta), medium-sized Evernia (Evernia mesomorpha) and Xanthoparmelia plitti was tested against various grampositive bacteria, including Pseudomonas aeruginosa, Escherichia coli, Proteus vulgaricus, Staphylococcus aureus, Streptococcus pneumoniae, and Bacillus subtilis and against several gram-negative too [9]. Nano-composites were fabricated by SiO 2 , Fe 3 O 4 , ZnO, and TiO 2 by Lecanora muralis against bacterial pathogens (Pseudomonas, Escherichia coli, Staphylococcus aureus) and fungal pathogens (Candida albicans and Candida) [10]. Even anti-mosquito gold nanoparticles were synthesized by using the lichen Parmelia sulcata extract against Anopheles stephensi [11]. Nanoparticles derived from metals and their oxides (such as silver, gold, titanium, cadmium, iron, zinc, and copper) appear to be synthesized using many lichens [12] [13]. Figure 1 shows that, lichen can fabricate NPs with several elements. This article focuses on the usefulness of lichen as a biological laboratory for the sustainable production of antibacterial metal nano-particles.

Analysis and Characterization of Nanoparticles from Lichen
Calculation of physical characteristics such as stability, crystallinity, charge, dispersion and optical properties is the most important stage in the production of nanoparticles (NPs). To understand this phenomenon, several spectroscopic approaches are required. Functional groups confirmation, charge evaluation and hydrodynamic diameter of NPs, nuclear magnetic resonance spectroscopy, UVvisible spectroscopy, dynamic light scattering, Fourier transform infrared (FTIR), zeta potential are common techniques. Chemical composition, crystal structure Journal of Materials Science and Chemical Engineering and phase of the fabricated NPs determined by X-ray-based analyses such as X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), and energy-dispersive spectroscopy (EDAX or EDS). Finally Microscopic techniques such as atomic force microscope, Scan electron microscope and Transmission electron microscope is practicing for morphological observation [14]. A schematic representation of analysis described in Figure 2.
Various methods, such as chemical and biomechanical solid-state synthesis, are used to synthesize lichen-based nanoparticles [15]. [4] reported that using the water extract of Parmotrema praesorediosum lichen as a reducing agent and stabilizer to synthesize silver nanoparticles by reducing silver nitrate. Use UVvisible spectroscopy, electron microscopy, energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) to characterize nanoparticles. The average size of the structured nanoparticles was 19 nm. [16] synthesized magnesium nanoparticles with an average size of 23 nm from Cladonia rangiferina, and they used light scattering and ultraviolet spectroscopy to characterize the nanoparticles. [8] Successfully synthesized silver nanoparticles by reducing silver nitrate with the water extract of Ramalina dumeticola lichen. The synthesis of silver nanoparticles in solution was confirmed by UV-Vis spectroscopy at 433 nm. Its appearance was characterized by transmission electron microscopy (TEM) and XRD, and it showed a cubic shape with an average size of 13 nm. [17] reported Acroscyphus sp. biosynthesis of gold nanoparticles. They are almost spherical and prismatic in shape, and are characterized by UV-Visible spectroscopy, Fourier transform infrared spectroscopy (FT-IR), powder XRD and TEM. [18] used Cetraria islandica's one-pot method to produce bimetallic nanocomposites with reduced lichen-reduced graphene oxide nanoparticles (LrGO) (LrGO-AgAu). The characterization of nanoparticles, so formed, was carried out using techniques such as TEM, scanning electron microscopy (SEM), XRD, and FT-IR.  [19] using solid-state mechanochemical synthesis methods, using pseudomonas pseudomonas and Lobaria pulmonaria to synthesize silver nanoparticles with an average particle size of 10 nm (some up to 100 nm).

Antimicrobial and Antibacterial Behaviour of Bio-Fabricated Lichen Based Nano-Particles
It is reported that many lichen-based nano-particles have antibacterial biological activity against various bacteria and fungi, which can be explained by their ability to destroy microbial membranes, oxidize various cellular components and generate hydroxyl free [20]. Applications of Lichen based NPs are summarized in Figure 3.

Action Mechanism of Lichen-Based Nano-Particles
The antimicrobial properties of lichen nanomaterials confirm their ability to disrupt the barrier of microbial cells (cell walls and membranes), enabling them to penetrate the cytoplasm and destroy cell components and genetic material, and ultimately terminate their metabolic functions (Figure 4; [23], however, Compared with 1) interference in the process of cell wall synthesis, 2) cell stress caused by reactive oxygen species (ROS), 3) interference in protein synthesis, and, 4) the proposed possible mechanism for the antibacterial activity of lichen nanoparticles Less. Changes in the transcription process, 5) changes in the main metabolic pathways, 6) introduction of genetic material and 7) changes in cell signaling [24]; however, studies have shown that antibacterial efficacy and the molecular mechanism of lichen nanomaterials depends on 1) the type of material, 2) the shape and size, 3) the composition of the microbial membrane, and 4) the physical and chemical state (pH, temperature, the presence of Co ions, the formation of biofilms, etc.) [25]. [21] demonstrated the antibacterial properties of silver nanoparticles driven by Usnea longissima by denaturing ribosomes, T. Ahsan et al. which led to the inactivation of enzymes and proteins, which eventually stopped their metabolic functions and led to bacterial apoptosis. [13] strictly reviewed 1) Pseudomonas aeruginosa [18] Journal of Materials Science and Chemical Engineering the green synthesis of Protoparmeliopsis muralis aqueous solution extracted from silver, copper, titanium oxide, zinc oxide and iron oxide nanoparticles and its related antibacterial properties. The total antioxidant capacity (TAC) and 2,2-diphenyl-1-pyridohydrazino hydrate (DPPH) were used to determine the antioxidant properties of the village shrimp. The results clearly show that copper and silver nanoparticles have better antioxidant and antibacterial properties than other nanoparticles. [9] reported that compared with Klebsiella-positive bacteria, silver nanoparticles based on xanthan skin and flavonoids have greater antibacterial activity against gram-negative bacteria, which may be related to the effect of nanoparticles on gram-negative bacteria. The permeability is stronger than that of Gramnegative bacteria. Gram-positive bacteria are caused by the thinning of the peptidoglycan layer on the cell wall. [18] reported the antibacterial properties of synthetic iron oxide nanoparticles from Chinese Lamarina extract. A study revealed the potential antibacterial effects of synthetic nanoparticles against Gram-positive and Gram-negative bacteria. The electrostatic interaction between the positively charged iron nanomaterials and the negatively charged bacterial cells can cause the bacterial membrane to be oxidized by iron ions and cause oxidative stress in the microbial cells. Cellular components and may cause cell death.

Future Prospective and Conclusion
According to reports, lichen-mediated nanoparticles are stable, inexpensive and biocompatible, making them ideal candidates for antibiotic use. Due to their unique physical and chemical properties, they can resist a variety of pathogenic microorganisms, such as Gram-positive and Gram-negative. Cost efficiency and cytotoxicity are some of the key issues, which need to be rigorously studied before a comprehensive study of candidate antibiotics in drugs. In addition, there are many obstacles to the biosynthetic process, including toxicity and agglomeration, polydispersity, stability, and inconsistent nanoparticle size. These prob-lems can be solved by intensive research to optimize the synthesis of the green woofer and obtain the required woofer. The mechanism of synthesizing NP from natural sources will help the development and adoption of nanomedicine in various fields.

Data Availability Statement
The data supporting this article are shown in Figures 1-4 and one table. The data sets analyzed in the present study are available from the corresponding author upon reasonable request.