Decubitus ulcers or bedsores notoriously known as pressure ulcers have not been studied immensely. Elderly people who shifted to long-term care facilities (LTCFs) are more prone to this type of ulcer, which is commonly seen in medical conditions. These ulcers are formed in bed-rest patients, by the pressure generated on the skin because of friction and the body weight for a longer period. Such initial pressure for approximately 1–2 h leads to pressure-induced cell deformation causing cell death. Pressure ulcers if untreated for a long time can also infect soft tissues, causing osteomyelitis and may even lead to death (in 39.7% of patients) (Rennert et al., 2009). P. aeruginosa, S. aureus, coagulase-negative Staphylococcus (CoNS), and E. faecalis are prominent microbes associated with pressure ulcers (Suleman and Percival, 2015). According to the National Pressure Ulcer Advisory Panel (NPUAP) and the European Pressure Ulcer Advisory Panel (EPUAP), pressure ulcers are categorized into four stages of wound infection, i.e., stage I (non-blanchable erythema), stage II (partial thickness), stage III (full thickness skin loss), and stage IV (full thickness tissue loss) (Panel, 2014). Medical sectors are under huge economic strain because of the increased cost of treatment of pressure ulcers, i.e., approximately £1,214 (category 1) to £14,108 (category IV) (Dealey et al., 2012). The peptide nucleic acid-based fluorescence in situ hybridization (PNA-FISH) studies by Kirketerp-Møller and colleagues on pressure ulcers revealed the existence of biofilms in it. Polymicrobial biofilm in association with S. aureus and C. albicans in this ulcer has been responsible for resistance to vancomycin (Harriott and Noverr, 2009).

Fazli and his colleagues used PNA-FISH to figure out that the VLU had biofilm (Fazli et al., 2011). P. aeruginosa is the persistent and prime bacterium responsible for chronic VLU. A leg ulcer is a long-lasting sore that usually develops on the inside of the leg, between the knee and the ankle. Its symptoms include pain, itching, swelling, and discoloration. The hardened skin around the ulcer and the sore may produce a discharge with a foul smell. There are two major causes for its development. It develops after a minor injury due to persistent high pressure in the veins of the legs. When there is high pressure in the veins of the lower leg, the veins become scarred and blocked, resulting in blood pooling in the legs. This is called venous insufficiency. The increased pressure and fluid buildup prevent nutrients and oxygen from reaching tissues. The lack of nutrients causes damage to the tissue and wound formation. Improvement of blood flow in the legs is a temporary method of treatment, and this internal environment facilitates the pathogens to develop a sustained colony as biofilm.

Approximately 15%–25% of the patients suffering from diabetes mellitus are prone to developing DFU (Armstrong et al., 2017). Diabetic foot complications are the most common cause of non-traumatic lower extremity amputations. A round, red crater in the skin bordered by thickened callused skin is the identifying feature of this disease. Poor control of blood sugar, foot deformities, bad foot care, shoes that do not fit right, peripheral neuropathy, poor circulation, and dry skin are the root causes. Slow recovery is one of the biggest problems with getting rid of this disease. This makes it easier for bacteria to take over the affected area, which causes biofilm to form. Routine practice for treatment includes optimizing diabetes control to reduce neuropathic and vascular complications. Implementing MADADORE (M = metabolic/medication; A = assessment; D = debridement; A = antibiotics; D = dressing; O = offloading; R = referral; E = education) is now being talked about in the medical community as a way to control it (Lazzarini et al., 2019).

Composites made up of polymer matrix and filler (clay, nanotubes, nanoparticles, etc.) with at least one dimension less than 100 nm are called polymer nanocomposites. Scratch-resistant transparent amorphous thermoplastic coating is the latest example of the modern application of polymer-based nanocomposite materials due to the small size of the fillers. Unlike traditional micron-filled composites, these novel fillers often alter the properties of the entire polymer matrix and, at the same time, impart new functionality because of their chemical composition and nanoscale size.

Ceramics have good wear resistance and high thermal and chemical stability. However, they are brittle. To overcome this limitation, ceramic–matrix nanocomposites (metal/ceramic and ceramic/ceramic) have been receiving attention along with metal/metal nanocomposites.

The use of chemicals have attracted attention from the public since they affect not just researchers and businesses but also the environment. To reduce this global concern, scientists have developed new ways to minimize it. In this context, natural products have played a vital role in fulfilling it. Mostly, plant parts and microbes are utilized for this purpose. Extracts of these have multiple roles, such as media for reactions, reducing agents, and capping agents. They are cheap as compared to chemicals, are easily available, and are easy to use—factors that contribute to the versatility of this technique, leading to the term “green.” Among various green nanoformulations, green nanocomposites have gained attention. To maintain a sustainable environment, green nanocomposites have played an important role through various applications in automotive, construction (Presting and Konig, 2003; Sharwani et al., 2022), packaging (Zare et al., 2019), and medical science (Bibi et al., 2021). They are based on eco-friendly materials. The biodegradable polymers generated provide solutions to the issues caused by synthetic and plastic waste. Green composites are composed of plant fibers and natural resins. We need to use synthetic polymers and/or additives as complements to green polymers. Green nanocomposites (either nanoscale natural macromolecules or biopolymers containing nanoparticles) are a class of scaffolds with acceptable biomedical properties (drug delivery and cardiac, nerve, bone, and cartilage as well as skin tissue engineering), enabling one to achieve the required level of skin regeneration and wound healing (Pathania et al., 2022).

There are various Gram-positive bacteria such as S. aureus and S. epidermidis that impede the healing of wounds (Roy et al., 2020). Studies reported that nanocomposites are more effective than pure NPs; for example, CuO embedded with Zn nanocomposite showed increased antibacterial activity compared with pure CuO or ZnO (Malka et al., 2013). Moreover, TiO₂-doped CuO and Li-doped MgO also have a significant antibacterial effect than pure MgO and TiO₂ (Rao et al., 2013). Similarly, CeO₂-CdO nanocomposites also had antimicrobial activity against Gram-negative bacteria (Magdalane et al., 2017). Furthermore, nanocomposite Mn and Fe ion-doped ZnO NPs have been observed to have higher antibacterial activity against a wide range of bacteria such as S. aureus, Bacillus subtilis, Proteus mirabilis, and E. coli compared with ZnO (Unal et al., 2018; Bahari et al., 2019). It was also seen that nanocomposites with metal oxides significantly improve the antimicrobial action through some external factor induction (Hsueh, 2010). Apart from this, a combination of three metal oxides like TiO₂-ZnO-MgO and CuZnFe oxide nanomaterials have higher antibacterial activity in inhibiting biofilm synthesis (Alzahrani et al., 2018). CuZnFe oxide NPs were found to be more effective against E. faecalis than ZnO NPs but less effective than CuO (Alzahrani et al., 2018). Thus, the nanocomposite with the combination of three NPs affected the biofilm formation to a higher degree than alone (Alzahrani et al., 2018). The mechanism behind the metal oxide NPs is that oxide causes the slow release of metal ions, which disrupt cellular processes by penetrating the cell membrane (Hayden et al., 2012). Metallic NPs cause severe oxidative stress through the generation of reactive oxygen species (ROS). The ROS level is in turn correlated with the antibacterial activity due to its damaging effect to the bacterial cell membrane, disrupting the nucleic acids, inhibiting the enzyme, and thus obstructing the biofilm formation (Ali et al., 2019; Song et al., 2019). Some studies report the effects of different nanocomposites such as biodegradable crosslinked polymer-stabilized oil-in-water, effective against bacterial biofilm (Landis et al., 2018). Nanocomposites are observed to be effective against the antibiotic-resistant bacterial biofilm of Gram-positive bacteria. A study has reported that a nanocomposite with immobilized ciprofloxacin results in the reduction of biofilm formation in S. aureus of up to 85%. This nanocomposite has higher antibacterial activity against Gram-positive bacteria compared with Gram-negative bacteria (Rumyantceva et al., 2021). This showed that nanocomposites have better antibacterial properties and are effective in treating Gram-positive bacteria such as S. aureus (Xu et al., 2021). Furthermore, it was observed that the dendritic collagen matrix embedded dexamethasone-silver nanoparticle biofilm was formed, which involved S. aureus (Ramyaa Shri et al., 2021). Another study reported that using Legistromia speciosa floral extract, the synthesis of graphene oxide-silver nanocomposite (GO-Ag) inhibited the Gram-negative (E. cloacae) biofilm formation (Kulshrestha et al., 2017). Moreover, combining graphene quantum dots (GQDs) and OH– radicals was observed to inhibit the biofilm formation of S. aureus by damaging the intercellular components (Sun et al., 2014). Polymethyl methacrylate (PMMA) incorporation into CNTs could also reduce the infections caused by microbes, such as S. mutans, S. aureus, and C. albicans, by affecting microbial adherence (Kim et al., 2019). Nanocomposite GO with Ag impedes the growth of S. aureus by preventing cell mitosis of bacterial cells (Singh et al., 2018). These studies indicated that nanocomposites have excellent antibacterial ability against Gram-positive bacteria. Thus, it can be used as a novel antimicrobial agent for treatment.

Nanocomposites are efficient against the development of resistant biofilms by Gram-negative bacteria as well as Gram-positive bacteria in various combinations. Same as Gram-positive bacteria, dendritic collagen matrix embedded dexamethasone-silver nanoparticles inhibit biofilm formation in the Gram-negative bacteria K. pneumoniae (Ramyaa Shri et al., 2021). A recent study has also observed that the AMP@PDA@AgNP nanocomposite has an inhibitory effect against Gram-negative bacteria, and E. coli and P. aeruginosa biofilm was higher than Gram-positive S. aureus. Furthermore, biofilm destruction in Gram-negative bacteria was also observed to be significantly different when compared with control (Xu et al., 2021). Moreover, nanocomposite immobilized with an antibiotic, ciprofloxacin, leads to reduced E. coli biofilm formation, and approximately 71% of its activity was even more effective compared with antibiotic alone (Rumyantceva et al., 2021). There are various studies that reported that, just like Gram-negative bacteria, there are various crosslinked polymer-stabilized oil-in-water and graphene oxide-silver nanocomposites that have antibacterial activity against Gram-negative bacteria biofilm formation (Kulshrestha et al., 2017; Landis et al., 2018). It has been seen that nanocomposites eradicated Gram-negative bacteria, including P. aeruginosa, E. coli, and E. cloacae complex in the biofilms (Li et al., 2019). These results indicated that nanocomposites are a better and novel approach for targeting resistant biofilm formation due to the wide range of Gram-negative bacteria. Apart from this, there were nanocomposites of copper, silver, or zinc NPs, embedded with zeolite, that were not effective against V. cholera biofilm formation, which showed that these bacteria have a resistance mechanism for these nanocomposites (Meza-Villezcas et al., 2019). Furthermore, the nanocomposite of silver NPs modified with curcumin causes oxidative stress through a hole in the membrane leading to antibacterial activity against B. subtilis and E. coli (Song et al., 2019). Similar to Gram-positive bacteria, metal oxides have antibacterial properties. For instance, mixing zinc and magnesium oxide with hydroxypropyl methylcellulose prevented P. mirabilis from forming a biofilm (Iribarnegaray et al., 2019). Another nanocomposite of octenyl succinic anhydride modified HA (OSA-HA) encapsulated antibiotic peptides, and poly D,L-lactic-co-glycolic acid (PLGA) disseminated the P. aeruginosa biofilm formation in lung mucus lining (Kłodzińska et al., 2019). Carbon NPs with an iron oxide nanocomposite have an antibacterial effect through the cell membrane, protein, and DNA degradation of E. coli (Alimardani et al., 2019). As we have already discussed, metal oxides have antibacterial activity, and ZnO, CuO, MgO, and TiO₂ doped with other metal nanoparticles have higher antibacterial activity against Gram-negative such as E. coli than any of them in pure form (Malka et al., 2013; Rao et al., 2013). Furthermore, the combination of three metal oxide nanoparticles such as CuZnFe oxides reduces E. coli biofilm formation ability more than individual oxides of metal alone (Alzahrani et al., 2018). These oxides release metals slowly, which can penetrate the cell membrane and affect the cellular processes (Hayden et al., 2012). The toxic effect of ZnO can be minimized significantly by doping iron or Mg, which is safe for mammalian cells (Vidic et al., 2013; Ravichandran et al., 2015). In addition, nickel oxide also showed antibacterial activity against the P. aeruginosa biofilm. The mechanism behind the antibacterial activity of NiO is that it affects DNA replication and protein synthesis and alters the cell membrane, which also leads to cell death (Maruthupandy et al., 2020). A study reported that the ZnO/CdS nanocomposite impedes P. aeruginosa biofilm formation and also reduces the biofilm microbial population (Gholap et al., 2020). Moreover, the addition of Ag and Au in nanocomposites enhances their antibacterial potential against resistant E. coli (Matai et al., 2014); for example, Ag-SiO₂ and Ag/Fe₃O₄ nanocomposites have increased antibacterial ability against E. coli (Mosselhy et al., 2017; Chang et al., 2018). The nanocomposite of ZnO NPs doped with Mn and Fe has also increased antibacterial activity against a wide range of bacteria such as E. coli, K. pneumoniae, S. typhi, P. aeruginosa, and P. mirabilis (Sharma et al., 2016; Bahari et al., 2019). Thus, as discussed previously, these nanocomposites with metal oxides have improved the efficacy of bacterial biofilm treatment through ROS generation and targeting bacterial DNA and proteins. Therefore, these results showed that choosing nanocomposites for biofilm treatment is the better way to treat biofilm-related infections.

The dynamics of certain indicators (such as oxygen level, pH, ions, and metabolite concentrations) within bacterial biofilms have been tracked using a variety of sensing techniques. The most effective method for a given application depends on several variables, including the type of target and the biofilm’s level of resistance to intrusive operations. For instance, highly sensitive and dependable electrochemical sensors are based on microelectrodes. To take the measurement, they must contact and pierce the biofilm, potentially endangering the biofilm’s structural integrity. Conversely, optical methods utilizing planar optodes and tiny particles are less intrusive. The biofilm’s oxygen and pH levels have been monitored using nanoparticles. Planar optodes, which are polymeric films embedded with oxygen-sensitive luminescent probes, and labeled micro- and nanoparticles have been employed in optical imaging systems based on confocal and fluorescence microscopy to monitor changes in oxygen and pH in the biofilm. Planar optodes, which are 2D polymer films on which the cells cling to form the biofilm, are unable to reveal information inside the biofilm. In contrast, micro- and nanoparticles doped with fluorescent or luminescent dyes, which are sensitive to changes in pH or oxygen levels in the biofilm, can be dispersed inside the EPS matrix, providing 3D mapping of the oxygen concentration and pH inside the biofilm. In situ studies of the biofilm can be conducted with less stress due to their non-destructive nature. The detection of heavy metal (Fe³⁺, Cu²⁺, Zn²⁺, and Hg²⁺) adsorption by bacterial biofilms that is pertinent to bioremediation applications has also been done using fluorescent probes (Funari and Shen, 2022).

The challenges of detecting biofilm in complex food samples, such as the characterization of biofilm formation mechanisms, identification of microbial metabolic activities, diagnosis of potential food pathogens, and sanitation monitoring of food processing equipment, have been taken on by optical nanosensors (Pu et al., 2021). Recently, nanosensors have been developed for biofilm optical detection with high sensitivity and great spatial resolution at nanoscale scopes that can convert biological information into optical signals (Talebi et al., 2019). Nanosensors, which are usually referred to as nanoprobes and nanozymes in microbiological detection due to their varied optical properties, can be tuned and designed for bacterium sensing and chemical recognition. The primary focus of nanosensors is on their capacity to transform chemical data from biomolecules in a microscopic environment into signals appropriate for detection. As a result, fluorescent, SERS, and colorimetric nanosensors make up the majority of optical nanosensors (Talebi et al., 2019).

Funari et al. have demonstrated that the utilization of localized surface plasmon resonance (LSPR) is done for label-free, in situ, real-time monitoring of E. coli biofilm formation on a gold mushroom-shaped nanoplasmonic substrate. By tracking the wavelength change in the LSPR resonance peak with fine temporal precision, the LSPR sensor can detect the traces of biofilm growth in real time (Funari et al., 2018). This sensor functions to analyze how different medications, such as kanamycin and ampicillin, as well as rifapentine, affect biofilm formation, preventing cell adhesion (Funari et al., 2018). LSPR-based technology is flexible and easy to use, making it a great tool for biofilm characterization and drug screening. It can be applied to a wide range of therapeutically relevant bacteria and provides an invaluable tool for drug screening and biofilm characterization (Funari et al., 2018).

There are recent advancements in biofilm prevention and control by using active antibiofilm nanocoatings. Antibiofilm tactics based on antimicrobial substances that eliminate infections and prevent their growth or interfere with the molecular pathways underlying the biofilm-associated rise in resistance and tolerance have been developed (Balaure and Grumezescu, 2020). These substances, which come in a variety of chemical forms, work in a variety of ways to target important bacterial metabolic pathways, cellular components including cell walls and membranes, or processes that underlie various stages of the biofilm life cycle. Eventually, smart antibiofilm coatings have been introduced that release their antimicrobial payload when necessary and are activated by a variety of triggers, including changes in the environment’s pH or temperature or enzymatic triggers.

Oxygen-sensitive luminescent nanosensors that can be incorporated into biofilms to study oxygen penetration, distribution, and antibiotic efficacy were successfully tested (Jewell et al., 2019). Sensors were used to track how antibiotics affect metabolism in biofilms made from clinical isolates. It not only provides a non-disruptive method for imaging and detecting oxygen in biofilms but also shows how to adapt a nanoparticle-based sensing platform to measure a variety of ions and small-molecule analytes (Jewell et al., 2019).

Antibiotic resistance among bacteria has evolved because of profound antibiotic stress. Likewise, P. aeruginosa evolve an elevated level of resistance to antibacterial agents via quorum sensing (QS) (Sadoq et al., 2023). With the advancement of antiviral therapies, the bacterial infection can be constrained without offending its resistance. In the phenomenon called QS, the bacteria correspond to each other in a density-dependent manner. This communication between the bacteria can be interrupted by disarming quorum-sensing systems. Such a strategy would save an ample amount of investment in the pharmaceutical industry. The Rhll/R system of P. aeruginosa is involved in the formation of biofilm. Molecular docking studies have shown the capability of silver, zinc, and copper oxide-based interactions with the acyl-homoserine-lactone synthases (LasI and RhII), thereby impeding the synthesis of functional signaling molecules. There are some regulatory proteins (LasR and RhIR) as well, which can bind to the nanoparticles, reducing the expression of QS-controlled genes (Sadoq et al., 2023).

These nanoparticles thwart the process of biofilm formation. Biofilm-based infections can be cured by intruding on the QS signaling cascade. pH, signal flow rate, and nutrient availability regulate QS-mediated biofilm function (Mishra et al., 2023). QS works by binding signaling molecules to the microbial receptors, instigating the activation of the gene network. Histidine kinase receptors sense the QS signals regulating gene expression in Gram-positive bacteria, which is nothing but the two-component regulating system, whereas receptive cell regulatory proteins after attaching to AHLs regulate the gene network in Gram-negative bacteria (Kalia, 2013).

Microbiology, nanotechnology, and optical technology are all involved in the multidisciplinary field of study on the imaging, identification, and chemical characterization of biofilms using optical nanosensors. Future studies on biofilm control will have a theoretical foundation due to the data collected by optical nanosensors, which include information on changes in biochemical contents as well as their spatial distribution and morphology.

They are a good choice to attack the unique target sites either in bacterial cell walls or non-selectively by generating bactericidal molecules. The antimicrobial properties of enzymes are attributed to their tendencies to aggregate or incorporate polymeric nanocomposites, which have potential in human therapeutics (Wu et al, 2017). Dispersin B (glycoside hydrolase), along with cefamandole nafate, is found to be a highly promising tool for preventing bacterial colonization of medical devices against S. epidermidis. Deoxyribonuclease I is also a potent anti-biofilm agent that acts by degrading extracellular DNA present in the matrix and rendering the matrix weaker and more susceptible to antimicrobials. DNase acts as a better anti-biofilm agent in individual biofilm formation than against the mixed species biofilms (Donelli et al., 2007; Sharma and Singh, 2018).

They are also known as nubiotics, which act as novel antimicrobials for enhanced killing of antibiotic-resistant and biofilm-forming bacteria. These are small protonated deoxynucleotide molecules that cause depolarization of bacterial cell membrane and also penetration of bacterial biofilms leading to death of encased bacteria (Wong et al., 2015).

The most abundant polyphenol found in green tea (Camella sinesis) is epigallocatechin gallate (EGCG) (Vidigal et al., 2014). Ellagic acid, esculetin, and fisetin are natural ingredients of dietary plants where fisetin was found to inhibit biofilm formation by S. aureus and S. dysgalactiae in a better manner than esculetin and ellagic acid. Esculetin, in turn, is found to be more efficient in preventing biofilms by S. aureus than ellagic acid. Ellagic acid prevents biofilm formation by S. dysgalactiae. Ellagic acid is also obtained from green tea while sources for esculetin are Santolina oblongifolia, Tagetes lucida, and Alchemilla speciosa, and those for fisetin are Vitis vinifera, Cucumis sativa, Fragaria ananassa, Allium cepa, Solanum lycopersicum, and Malus domestica (Durig et al., 2020).

Chitosan (a polysaccharide), curcumin (a beta diketone), eugenol (a phenol), and linoleic acid (omega-6-fatty acid) are antibacterial while berberine and resperine suppress biofilm formation in K. pneumoniae. The source of curcumin is Curcuma longa; that of eugenol is Syzigium aromaticum and Ocimum plants; that of linoleic acid is Coptis chinensis, Berberis vulgaris, B. aquifolium, B. aristata, and Hydrastis canadensis; that of berberine is Berberis aristata, B. vulgaris, and B. aquifolium; and that of Resperine is Rauwolfia serpentine and R. vomitoria (Magesh et al., 2013). Quercetin is obtained from Usnea longissima and it acts against biofilms of K. pneumoniae, Campylobacter violaccum, and P. aeruginosa (Gopu et al., 2015).

The synthetic halogenated Furanone (F-56) compound is derived from natural Furanone. It is produced by Australian macro alga Delisea pulchra and causes detachment of biomass of E. coli and P. aeruginosa (Hentzer et al., 2002).

A previous study demonstrated the effect of an antimicrobial peptide derived from the stomach of the toad, Buforin-II, which enters the cell and binds to the nucleic acid to kill it without any membrane permeabilization (Cho et al., 2009). A small lytic peptide PTP-7 was found to be capable of diffusing into deeper layers of S. aureus biofilms to kill the bacteria effectively, thus providing a very good alternative to antibiotics for controlling infections related to bacterial biofilms (Kharidia and Liang, 2011). Two antibacterial peptides, cecropin P1 and PR-39, can be obtained from the intestine of a pig. Cecropin can kill E. coli in association with more peptides while PR-39 is capable of killing wild-type E. coli (Boman et al., 1993). Indolicidin was isolated from bovine neutrophils and found to inhibit E. coli DNA synthesis, making this antimicrobial agent of significant use in human therapeutics (Subbalakshmi and Sitaram, 1998). The antibiotic microcin B17 is a bactericidal peptide that acts as a poison for the DNA replication enzyme DNA gyrase, hence killing the bacteria (Vizan et al., 1991). Similarly, lytic peptide (PTP-7), a synthetic analog from Gaegurin 5; LL-37, a human cationic host defense peptide; PMAP-23, a cathelicidin-derived peptide identified from porcine leukocytes; and sushi peptides, derived from the sushi-3 domain of factor C, which is an LPS-sensitive serine protease of horseshow crab coagulation cascade, are potent anti-biofilm agents. Peptide 1018 is a small peptide that has the potential to eradicate Acinetobacter baumannii, E. coli, K. pneumoniae, P. aeruginosa, S. aureus, and Salmonella typhimurium biofilms at high doses and even checks the formation of biofilms (Fuente-Núñez et al., 2014). This peptide is derived from bovine host defense peptide bactenecins found in neutrophil granules.

CFT073 group II capsular polysaccharide is produced by extraintestinal E. coli of phylogenetic group B2 or D. These have the potential to inhibit biofilm formation by E. faecalis, E. coli, K. pneumoniae, P. aeruginosa, S. aureus, and S. epidermidis (Rendueles et al., 2013). Two additional anti-biofilm polysaccharides, Pel and Psl, were identified in a similar study and were found to be effective against E. coli and Staphylococcus epidermidis biofilms (Qin et al., 2009; Liang, 2015).

Gallidermin, which is obtained from Staphylococcus gallinarum, is found to prevent biofilm formation by S. aureus and S. epidermidis (Saising et al., 2012). Subtilin is another antibiotic that is considered similar to Nisin. Both are known to destroy bacterial biofilms by creating membrane pores in S. simulans and B. subtilis cells. Subtilin is sourced from B. subtilis Strain ATCC6633, Nisin is sourced from Lactococcus lactis, and Epidermin is sourced from S. epidermidis (Parisot et al., 2008).

These are the category of hydrophobic or hydrophilic biosurfactants that are produced on microbial cells or excreted extracellularly. Their antimicrobial property is attributed to the tendency to disrupt biofilms and the prevention of biofilm formation (Rienzo et al., 2015). Colistin is a polymixin E, obtained from Paenibacillus polymyxa, and is known to check biofilm formation against S. aureus for cystic fibrosis infections in lungs (Vidigal et al., 2014), while polymixin B is another biosurfactant and has the potential to combat multidrug-resistant bacteria and their biofilms (Park et al., 2011).

An interesting study reported that chelating agents can disrupt the architecture of biofilms to destabilize bacterial membranes (Shadia and Aeron, 2014). Sodium citrate, tetrasodium EDTA, and disodium EDTA with tigecycline or gentamicin could reduce biofilms of Staphylococcus species and P. aeruginosa.

A bacteriophage-encoded enzyme endolysin, Ply C, can potentially act against the biofilms of Streptococcus (Shen et al., 2013). Ply C acts as a cell wall hydrolase enzyme to destroy the static and dynamic biofilms by diffusing through the matrix. It interacts with the cell surface carbohydrate that is peptidoglycan of the cell wall and has one enzyme active domain (EAD) to hydrolyze peptidoglycan bonds and another cell binding domain (CBD) in it (King et al., 2021).

Silver and iodine are employed as antimicrobials to help suppress the biofilms in chronic wounds (Percival et al., 2014). Octenidine hydrochloride, chlorhexidine, and cadexomer iodine polyhexamethylenebiguanide are also known antimicrobial agents. Gold nanoparticles integrated with graphitic carbon nitride (g-C3N4) have bactericidal effects against drug-resistant E. coli and S. aureus when combined with hydrogen peroxide (Wang et al., 2017). This has not only reduced bacterial infections but also accelerated wound healing rate.

Tannic acid was found to inhibit surface colonization in S. aureus (Payne et al, 2013) while usnic acid is a natural secondary lichen metabolite that acts as an antimicrobial agent for inhibiting the formation of bacterial biofilms even on polymeric surfaces (Francolini et al, 2004) and also inhibits the virulent morphological traits of Candida albicans (Nithyanand et al, 2015).