Biosurfactants’ Potential Role in Combating COVID-19 and Similar Future Microbial Threats

Potential anti-aging applications of microbial-derived surfactantsin cosmetic formulations

The skin aging process is a complex interaction of genetic, epigenetic, and environmental factors, such as chemical pollution and UV radiation. There is growing evidence that biosurfactants, especially those of microbial origin, have distinct age-supportive effects through different mechanisms, such as stimulation of fibroblast growth, high antioxidant capacities, and favorable anti-inflammatory properties. With a growing financial contribution of more than 15 m€per year, microbial surfactants (MSs) display unique biological effects on the skin including improved cell mobility, better nutrient access, and facilitated cellular growth under harsh conditions. Their biodegradable nature, unusual surface activity, good safety profile and tolerance to high temperature and pH variations widen their potential spectrum in biomedical and pharmaceutical applications. MSs typically have lower critical micelle concentration (CMC) levels than chemical surfactants enhancing their effectiveness. As natural surfactants, MSs are considered possible "green" alternatives to synthetic surfactants with better biodegradability, sustainability, and beneficial functional properties. This review therefore aims to explore the potential impacts of MSs as anti-aging ingredients.

Sustainable biorefinery approach by utilizing xylose fraction of lignocellulosic biomass

Lignocellulosic biomass (LCB) has been a lucrative feedstock for developing biochemical products due to its rich organic content, low carbon footprint and abundant accessibility. The recalcitrant nature of this feedstock is a foremost bottleneck. It needs suitable pretreatment techniques to achieve a high yield of sugar fractions such as glucose and xylose with low inhibitory components. Cellulosic sugars are commonly used for the bio-manufacturing process, and the xylose sugar, which is predominant in the hemicellulosic fraction, is rejected as most cell factories lack the five‑carbon metabolic pathways. In the present review, more emphasis was placed on the efficient pretreatment techniques developed for disintegrating LCB and enhancing xylose sugars. Further, the transformation of the xylose to value-added products through chemo-catalytic routes was highlighted. In addition, the review also recapitulates the sustainable production of biochemicals by native xylose assimilating microbes and engineering the metabolic pathway to ameliorate biomanufacturing using xylose as the sole carbon source. Overall, this review will give an edge on the bioprocessing of microbial metabolism for the efficient utilization of xylose in the LCB.

Microbial Biosurfactants: Antimicrobial Activity and Potential Biomedical and Therapeutic Exploits

The rapid emergence of multidrug-resistant pathogens worldwide has raised concerns regarding the effectiveness of conventional antibiotics. This can be observed in ESKAPE pathogens, among others, whose multiple resistance mechanisms have led to a reduction in effective treatment options. Innovative strategies aimed at mitigating the incidence of antibiotic-resistant pathogens encompass the potential use of biosurfactants. These surface-active agents comprise a group of unique amphiphilic molecules of microbial origin that are capable of interacting with the lipidic components of microorganisms. Biosurfactant interactions with different surfaces can affect their hydrophobic properties and as a result, their ability to alter microorganisms' adhesion abilities and consequent biofilm formation. Unlike synthetic surfactants, biosurfactants present low toxicity and high biodegradability and remain stable under temperature and pH extremes, making them potentially suitable for targeted use in medical and pharmaceutical applications. This review discusses the development of biosurfactants in biomedical and therapeutic uses as antimicrobial and antibiofilm agents, in addition to considering the potential synergistic effect of biosurfactants in combination with antibiotics. Furthermore, the anti-cancer and anti-viral potential of biosurfactants in relation to COVID-19 is also discussed.

Biosurfactant potential and antiviral activity of multistrain probiotics

The COVID-19 caused by the SARS-CoV-2 has become a great threat to humans. However, there is no recommendation for an effective and safe drug to treat the disease. The strategy developed in this study is to utilize biosurfactant potential activity of Lactobacillus spp. and Rhodopseudomonas palustris probiotics to prevent the virus from entering human body. The outer membrane of the virus is comprising of phospholipid compounds. Biosurfactants, are known to have detergent-like properties (able to dissolve lipids) that are safe for in vivo use. Thus, the biosurfactant potential activity of the multistrain probiotics extract is expected to be able to disrupt the phospholipid membrane, resulting in the inactivity of the virus to infect human body. The biosurfactant potential activity of the probiotics extract was evaluated using oil spreading, drop collapse, and emulsification methods. The virus infectivity was evaluated on the SARS-CoV-2 of delta variant as a virus model. The results indicated that the probiotics extract has biosurfactant potential activity, able to inhibit virus growth up to 99.9 % within 48 h in the prevention platform, and up to 99.6 % within 48 h in the treatment platform. Therefore, the multistrain probiotics extract was identified to have potential as a promising antiviral agent.

A comprehensive review of biosurfactant production and its uses in the pharmaceutical industry

Biosurfactants are naturally occurring, surface-active chemicals generated by microorganisms and have attracted interest recently because of their numerous industrial uses. Compared to their chemical equivalents, they exhibit qualities that include lower toxic levels, increased biodegradable properties, and unique physiochemical properties. Due to these traits, biosurfactants have become attractive substitutes for synthetic surfactants in the pharmaceutical industry. In-depth research has been done in the last few decades, demonstrating their vast use in various industries. This review article includes a thorough description of the various types of biosurfactants and their production processes. The production process discussed here is from oil-contaminated waste, agro-industrial waste, dairy, and sugar industry waste, and also how biosurfactants can be produced from animal fat. Various purification methods such as ultrafiltration, liquid-liquid extraction, acid precipitation, foam fraction, and adsorption are required to acquire a purified product, which is necessary in the pharmaceutical industry, are also discussed here. Alternative ways for large-scale production of biosurfactants using different statistical experimental designs such as CCD, ANN, and RSM are described here. Several uses of biosurfactants, including drug delivery systems, antibacterial and antifungal agents, wound healing, and cancer therapy, are discussed. Additionally, in this review, the future challenges and aspects of biosurfactant utilization in the pharmaceutical industry and how to overcome them are also discussed.

Statistical Optimization of Biosurfactant Production from Aspergillus niger SA1 Fermentation Process and Mathematical Modeling

In this study, we sought to investigate the production and optimization of biosurfactants by soil fungi isolated from petroleum oil-contaminated soil in Saudi Arabia. Forty-four fungal isolates were isolated from ten petroleum oil-contaminated soil samples. All isolates were identified using the internal transcribed spacer (ITS) region, and biosurfactant screening showed that thirty-nine of the isolates were positive. Aspergillus niger SA1 was the highest biosurfactant producer, demonstrating surface tension, drop collapsing, oil displacement, and an emulsification index (E24) of 35.8 mN/m, 0.55 cm, 6.7 cm, and 70%, respectively. This isolate was therefore selected for biosurfactant optimization using the Fit Group model. The biosurfactant yield was increased 1.22 times higher than in the nonoptimized medium (8.02 g/l) under conditions of pH 6, temperature 35°C, waste frying oil (5.5 g), agitation rate of 200 rpm, and an incubation period of 7 days. Model significance and fitness analysis had an RMSE score of 0.852 and a p-value of 0.0016. The biosurfactant activities were surface tension (35.8 mN/m), drop collapsing (0.7 cm), oil displacement (4.5 cm), and E24 (65.0%). The time course of biosurfactant production was a growth-associated phase. The main outputs of the mathematical model for biomass yield were Yx/s (1.18), and μmax (0.0306) for biosurfactant yield was Yp/s (1.87) and Yp/x (2.51); for waste frying oil consumption the So was 55 g/l, and Ke was 2.56. To verify the model's accuracy, percentage errors between biomass and biosurfactant yields were determined by experimental work and calculated using model equations. The average error of biomass yield was 2.68%, and the average error percentage of biosurfactant yield was 3.39%.

Harnessing the Potential of Biosurfactants for Biomedical and Pharmaceutical Applications

Biosurfactants (BSs) are microbial compounds that have emerged as potential alternatives to chemical surfactants due to their multifunctional properties, sustainability and biodegradability. Owing to their amphipathic nature and distinctive structural arrangement, biosurfactants exhibit a range of physicochemical properties, including excellent surface activity, efficient critical micelle concentration, humectant properties, foaming and cleaning abilities and the capacity to form microemulsions. Furthermore, numerous biosurfactants display additional biological characteristics, such as antibacterial, antifungal and antiviral effects, and antioxidant, anticancer and immunomodulatory activities. Over the past two decades, numerous studies have explored their potential applications, including pharmaceuticals, cosmetics, antimicrobial and antibiofilm agents, wound healing, anticancer treatments, immune system modulators and drug/gene carriers. These applications are particularly important in addressing challenges such as antimicrobial resistance and biofilm formations in clinical, hygiene and therapeutic settings. They can also serve as coating agents for surfaces, enabling antiadhesive, suppression, or eradication strategies. Not least importantly, biosurfactants have shown compatibility with various drug formulations, including nanoparticles, liposomes, micro- and nanoemulsions and hydrogels, improving drug solubility, stability and bioavailability, and enabling a targeted and controlled drug release. These qualities make biosurfactants promising candidates for the development of next-generation antimicrobial, antibiofilm, anticancer, wound-healing, immunomodulating, drug or gene delivery agents, as well as adjuvants to other antibiotics. Analysing the most recent literature, this review aims to update the present understanding, highlight emerging trends, and identify promising directions and advancements in the utilization of biosurfactants within the pharmaceutical and biomedical fields.

Galdieria sulphuraria: An Extremophilic Alga as a Source of Antiviral Bioactive Compounds

In the last decades, the interest in bioactive compounds derived from natural sources including bacteria, fungi, plants, and algae has significantly increased. It is well-known that aquatic or terrestrial organisms can produce, in special conditions, secondary metabolites with a wide range of biological properties, such as anticancer, antioxidant, anti-inflammatory, and antimicrobial activities. In this study, we focused on the extremophilic microalga Galdieria sulphuraria as a possible producer of bioactive compounds with antiviral activity. The algal culture was subjected to organic extraction with acetone. The cytotoxicity effect of the extract was evaluated by the 2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The antiviral activity was assessed through a plaque assay against herpesviruses and coronaviruses as enveloped viruses and poliovirus as a naked one. The monolayer was treated with different concentrations of extract, ranging from 1 µg/mL to 200 µg/mL, and infected with viruses. The algal extract displayed strong antiviral activity at non-toxic concentrations against all tested enveloped viruses, in particular in the virus pre-treatment against HSV-2 and HCoV-229E, with IC₅₀ values of 1.7 µg/mL and IC₉₀ of 1.8 µg/mL, respectively. However, no activity against the non-enveloped poliovirus has been detected. The inhibitory effect of the algal extract was confirmed by the quantitative RT-PCR of viral genes. Preliminary chemical profiling of the extract was performed using ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS), revealing the enrichment in primary fatty acid amides (PFAA), such as oleamide, palmitamide, and pheophorbide A. These promising results pave the way for the further purification of the mixture to explore its potential role as an antiviral agent.

Thermodynamic Characterization of Rhamnolipid, Triton X-165 and Ethanol as well as Their Mixture Behaviour at the Water-Air Interface

In many industrial fields, in medicine or pharmacy, there are used multi-component mixtures of surfactants as well as more and more often mixtures containing biosurfactants. Thus, in our study the mixtures of rhamnolipid (RL), ethanol (ET) and Triton X-165 (TX165) were applied. For these mixtures the surface tension of aqueous solutions with constant concentration and composition of ET and RL as well as the variable concentration of TX165 was measured. Based on the obtained results and the literature data, thermodynamic analyses of the adsorption process of ET, RL, TX165, binary mixtures of ET + RL, ET + TX165 and RL + TX165 as well as the ternary mixtures of RL + ET + TX165 at the water-air interface were made. This analysis allows to propose a new equation for calculation of the total ethanol concentration at the water-air interface using the Guggenheim-Adam adsorption isotherm. The constants in the Langmuir and Szyszkowski equations for each component of the studied mixtures as well as the composition of the mixed monolayer at the water-air interface were also successfully analysed based on the contribution of particular surface active compounds to the water surface tension reduction as well as based on the Frumkin isotherm of adsorption.

The paradigm of prophylactic viral outbreaks measures by microbial biosurfactants

The recent emergence and outbreak of the COVID-19 pandemic confirmed the incompetence of countries across the world to deal with a global public health emergency. Although the recent advent of vaccines is an important prophylactic measure, effective clinical therapy for SARS-Cov-2 is yet to be discovered. With the increasing mortality rate, research has been focused on understanding the pathogenic mechanism and clinical parameters to comprehend COVID-19 infection and propose new avenues for naturally occurring molecules with novel therapeutic properties to alleviate the current situation. In accordance with recent clinical studies and SARS-CoV-2 infection markers, cytokine storm and oxidative stress are entwined pathogenic processes in COVID-19 progression. Lately, Biosurfactants (BSs) have been studied as one of the most advanced biomolecules of microbial origin with anti-inflammatory, antioxidant, antiviral properties, antiadhesive, and antimicrobial properties. Therefore, this review inspects available literature and proposes biosurfactants with these properties to be encouraged for their extensive study in dealing with the current pandemic as new pharmaceutics in the prevention and control of viral spread, treating the symptoms developed after the incubation period through different therapeutic approaches and playing a potential drug delivery model.

Bacterial-derived surfactants: an update on general aspects and forthcoming applications

The search for sustainable alternatives to the production of chemicals using renewable substrates and natural processes has been widely encouraged. Microbial surfactants or biosurfactants are surface-active compounds synthesized by fungi, yeasts, and bacteria. Due to their great metabolic versatility, bacteria are the most traditional and well-known microbial surfactant producers, being Bacillus and Pseudomonas species their typical representatives. To be successfully applied in industry, surfactants need to maintain stability under the harsh environmental conditions present in manufacturing processes; thus, the prospection of biosurfactants derived from extremophiles is a promising strategy to the discovery of novel and useful molecules. Bacterial surfactants show interesting properties suitable for a range of applications in the oil industry, food, agriculture, pharmaceuticals, cosmetics, bioremediation, and more recently, nanotechnology. In addition, they can be synthesized using renewable resources as substrates, contributing to the circular economy and sustainability. The article presents a general and updated review of bacterial-derived biosurfactants, focusing on the potential of some groups that are still underexploited, as well as, recent trends and contributions of these versatile biomolecules to circular bioeconomy and nanotechnology.

Pharmaceutical prospects of biosurfactants produced from fungal species

The development of novel types of biogenic surface-active compounds is of greater interest for combating many diseases and infections. In this respect research and development of biosurfactant has gained immense importance. Substantially, biosurfactant is defined as a class of active amphiphilic chemical compounds that comprise hydrophobic and hydrophilic moieties on their surfaces. It is generally known that many kinds of microorganisms can be used to produce these surfactants or surface-active compounds. Hosting interesting features such as biodegradability, emulsifying/de-emulsifying capacity, low toxicity, and antimicrobial activities; these amphiphilic compounds in recent years have flourished as an ideal replacement for the chemically synthesized surfactant, and also have various commercial attractions. Both bacteria and fungi are the producers of these amphiphilic molecules; however, the pathogenicity of certain bacterial strains has caused a shift in interest toward fungi. Therefore, various fungi species have been reported for the production of biosurfactants amongst which Candida species have been the most studied strains. Biosurfactants uphold desired properties like antibacterial, antifungal, antiviral, antiadhesion, and anticancer activity which proves them an ideal candidate for the application in various fields like pharmaceutical, gene therapy, medical insertion safety, immunotherapy to fight against many chronic diseases, and so forth. Hence, this review article discusses the pharmaceutical prospects of biosurfactants produced from different fungal species, providing new directions toward the discovery and development of molecules with novel structures and diverse functions for advanced application in the medical field.

Guava Seed Oil: Potential Waste for the Rhamnolipids Production

Guava is consumed in natura and is also of considerable importance to the food industry. The seeds and peel of this fruit are discarded, however, guava seeds yield oil (~13%) that can be used for the bioproducts synthesis. The use of a by-product as a carbon source is advantageous, as it reduces the environmental impact of possible harmful materials to nature, while adding value to products. In addition, the use of untested substrates can bring new yield and characterization results. Thus, this research sought to study rhamnolipids (RLs) production from guava seed oil, a by-product of the fructorefinery. The experiments were carried out using Pseudomonas aeruginosa LBI 2A1 and experimental design was used to optimize the variables Carbon and Nitrogen concentration. Characterization of RLs produced occurred by LC-MS. In this study, variables in the quadratic forms and the interaction between them influenced the response (p < 0.05). The most significant variable was N concentration. Maximum RLs yield achieved 39.97 g/L, predominantly of mono-RL. Characterization analysis revealed 9 homologues including the presence of RhaC10C14:2 (m/z 555) whose structure has not previously been observed. This research showed that guava seed oil is an alternative potential carbon source for rhamnolipid production with rare rhamnolipid homologues.

Production of biosurfactants from agro-industrial waste and waste cooking oil in a circular bioeconomy: An overview

Waste generation is becoming a global concern owing to its adverse effects on environment and human health. The utilization of waste as a feedstock for production of value-added products has opened new avenues contributing to environmental sustainability. Microorganisms have been employed for production of biosurfactants as secondary metabolites by utilizing waste streams. Utilization of waste as a substrate significantly reduces the cost of overall process. Biosurfactant(s) derived from these processes can be utilized in environmental and different industrial sectors. This review focuses on global market of biosurfactants followed by discussion on production of biosurfactants from waste streams such as agro-industrial waste and waste cooking oil. The need for waste stream derived circular bioeconomy and scale up of biosurfactant production have been narrated with applications of biosurfactants in environment and industrial sectors. Road blocks and future directions for research have also been discussed.

Production of mannosylerythritol lipids: biosynthesis, multi-omics approaches, and commercial exploitation

Compilation of resources regarding MEL biosynthesis, key production parameters; available omics resources and current commercial applications, for smut fungi known to produce MELs.

Antiviral Activity of the Rhamnolipids Mixture from the Antarctic Bacterium Pseudomonas gessardii M15 against Herpes Simplex Viruses and Coronaviruses

Emerging and re-emerging viruses represent a serious threat to human health at a global level. In particular, enveloped viruses are one of the main causes of viral outbreaks, as recently demonstrated by SARS-CoV-2. An effective strategy to counteract these viruses could be to target the envelope by using surface-active compounds. Rhamnolipids (RLs) are microbial biosurfactants displaying a wide range of bioactivities, such as antibacterial, antifungal and antibiofilm, among others. Being of microbial origin, they are environmentally-friendly, biodegradable, and less toxic than synthetic surfactants. In this work, we explored the antiviral activity of the rhamnolipids mixture (M15RL) produced by the Antarctic bacteria Pseudomonas gessardii M15 against viruses belonging to Coronaviridae and Herpesviridae families. In addition, we investigated the rhamnolipids’ mode of action and the possibility of inactivating viruses on treated surfaces. Our results show complete inactivation of HSV-1 and HSV-2 by M15RLs at 6 µg/mL, and of HCoV-229E and SARS-CoV-2 at 25 and 50 µg/mL, respectively. Concerning activity against HCoV-OC43, 80% inhibition of cytopathic effect was recorded, while no activity against naked Poliovirus Type 1 (PV-1) was detectable, suggesting that the antiviral action is mainly directed towards the envelope. In conclusion, we report a significant activity of M15RL against enveloped viruses and demonstrated for the first time the antiviral effect of rhamnolipids against SARS-CoV-2.

Nanoemulsions: Formulation, characterization, biological fate, and potential role against COVID-19 and other viral outbreaks

Viral diseases are emerging as global threats. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), that causes coronavirus disease (COVID-19), has severe global impacts. Safety, dosage, and potency of vaccines recently approved for emergency use against SARS-CoV-2 need further evaluation. There is still no effective treatment against COVID-19; therefore, safe, and effective vaccines or therapeutics against SARS-CoV-2 are urgently needed. Oil-in-water nanoemulsions (O/W NEs) are emerging as sophisticated, protective, and therapeutic platforms. Encapsulation capacity, which offers better drug pharmacokinetics, coupled with the tunable surfaces present NEs as promising tools for pharmaceutical applications. The challenges facing drug discovery, and the advancements of NEs in drug delivery demonstrate the potential of NEs against evolving diseases, like COVID-19. Here we summarize current COVID-19 knowledge and discuss the composition, stability, preparation, characterization, and biological fate of O/W NEs. We also provide insights into NE structural-functional properties that may contribute to therapeutic or preventative solutions against COVID-19.

Surfactants - Compounds for inactivation of SARS-CoV-2 and other enveloped viruses

We provide here a general view on the interactions of surfactants with viruses, with a particular emphasis on how such interactions can be controlled and employed for inhibiting the infectivity of enveloped viruses, including coronaviruses. The aim is to provide to interested scientists from different fields, including chemistry, physics, biochemistry, and medicine, an overview of the basic properties of surfactants and (corona)viruses, which are relevant to understanding the interactions between the two. Various types of interactions between surfactant and virus are important, and they act on different components of a virus such as the lipid envelope, membrane (envelope) proteins and nucleocapsid proteins. Accordingly, this cannot be a detailed account of all relevant aspects but instead a summary that bridges between the different disciplines. We describe concepts and cover a selection of the relevant literature as an incentive for diving deeper into the relevant material. Our focus is on more recent developments around the COVID-19 pandemic caused by SARS-CoV-2, applications of surfactants against the virus, and on the potential future use of surfactants for pandemic relief. We also cover the most important aspects of the historical development of using surfactants in combatting virus infections. We conclude that surfactants are already playing very important roles in various directions of defence against viruses, either directly, as in disinfection, or as carrier components of drug delivery systems for prophylaxis or treatment. By designing tailor-made surfactants, and consequently, advanced formulations, one can expect more and more effective use of surfactants, either directly as antiviral compounds or as part of more complex formulations.

Fungal biosurfactants, from nature to biotechnological product: bioprospection, production and potential applications

Biosurfactants are in demand by the global market as natural commodities that can be added to commercial products or use in environmental applications. These biomolecules reduce the surface/interfacial tension between fluid phases and exhibit superior stability to chemical surfactants under different physico-chemical conditions. Biotechnological production of biosurfactants is still emerging. Fungi are promising producers of these molecules with unique chemical structures, such as sophorolipids, mannosylerythritol lipids, cellobiose lipids, xylolipids, polyol lipids and hydrophobins. In this review, we aimed to contextualize concepts related to fungal biosurfactant production and its application in industry and the environment. Concepts related to the thermodynamic and physico-chemical properties of biosurfactants are presented, which allows detailed analysis of their structural and application. Promising niches for isolating biosurfactant-producing fungi are presented, as well as screening methodologies are discussed. Finally, strategies related to process parameters and variables, simultaneous production, process optimization through statistical and genetic tools, downstream processing and some aspects of commercial products formulations are presented.

Influence of Lactobacillus Biosurfactants on Skin Permeation of Hydrocortisone

One of the most widely used strategies to improve drug diffusion through the skin is the use of permeation enhancers. The aim of this work was to investigate the effect of two biosurfactants (BS), produced by Lactobacillus crispatus BC1 and Lactobacillus gasseri BC9, on the skin permeation profile of hydrocortisone (HC, model drug). HC aqueous solubility and in vitro diffusion studies through porcine skin were performed in the presence of BC1-BS and BC9-BS at concentrations below and above critical micellar concentrations (CMC). Moreover, skin hydration tests and differential scanning calorimetry (DSC) analysis were performed to further investigate BS interaction with the outermost layer of the skin. Both BS increased HC solubility, especially at concentrations above their CMC. At concentrations below the CMC, drug permeation through the skin was improved, as the result of a dual effect: a) the formation of a superficial lipophilic environment, as confirmed by the reduction in skin hydration and b) the interaction between BS and the stratum corneum (SC), as demonstrated by the DSC curves. From the obtained data, it appears that BC1-BS and BC9-BS could represent new promising green excipients for drug permeation enhancement through the skin.

Recent Advances in Biomedical, Therapeutic and Pharmaceutical Applications of Microbial Surfactants

The spread of antimicrobial-resistant pathogens typically existing in biofilm formation and the recent COVID-19 pandemic, although unrelated phenomena, have demonstrated the urgent need for methods to combat such increasing threats. New avenues of research for natural molecules with desirable properties to alleviate this situation have, therefore, been expanding. Biosurfactants comprise a group of unique and varied amphiphilic molecules of microbial origin capable of interacting with lipidic membranes/components of microorganisms and altering their physicochemical properties. These features have encouraged closer investigations of these microbial metabolites as new pharmaceutics with potential applications in clinical, hygiene and therapeutic fields. Mounting evidence has indicated that biosurfactants have antimicrobial, antibiofilm, antiviral, immunomodulatory and antiproliferative activities that are exploitable in new anticancer treatments and wound healing applications. Some biosurfactants have already been approved for use in clinical, food and environmental fields, while others are currently under investigation and development as antimicrobials or adjuvants to antibiotics for microbial suppression and biofilm eradication strategies. Moreover, due to the COVID-19 pandemic, biosurfactants are now being explored as an alternative to current products or procedures for effective cleaning and handwash formulations, antiviral plastic and fabric surface coating agents for shields and masks. In addition, biosurfactants have shown promise as drug delivery systems and in the medicinal relief of symptoms associated with SARS-CoV-2 acute respiratory distress syndrome.

Nanotechnology-Based Antimicrobial and Antiviral Surface Coating Strategies

Biocontamination of medical devices and implants is a growing issue that causes medical complications and increased expenses. In the fight against biocontamination, developing synthetic surfaces, which reduce the adhesion of microbes and provide biocidal activity or combinatory effects, has emerged as a major global strategy. Advances in nanotechnology and biological sciences have made it possible to design smart surfaces for decreasing infections. Nevertheless, the clinical performance of these surfaces is highly depending on the choice of material. This review focuses on the antimicrobial surfaces with functional material coatings, such as cationic polymers, metal coatings and antifouling micro-/nanostructures. One of the highlights of the review is providing insights into the virus-inactivating surface development, which might particularly be useful for controlling the currently confronted pandemic coronavirus disease 2019 (COVID-19). The nanotechnology-based strategies presented here might be beneficial to produce materials that reduce or prevent the transmission of airborne viral droplets, once applied to biomedical devices and protective equipment of medical workers. Overall, this review compiles existing studies in this broad field by focusing on the recent related developments, draws attention to the possible activity mechanisms, discusses the key challenges and provides future recommendations for developing new, efficient antimicrobial and antiviral surface coatings.