Facile coating of urinary catheter with bio-inspired antibacterial coating

N-Acetyl Cysteine-Decorated Nitric Oxide-Releasing Interface for Biomedical Applications

Biomedical devices are vulnerable to infections and biofilm formation, leading to extended hospital stays, high expenditure, and increased mortality. Infections are clinically treated via the administration of systemic antibiotics, leading to the development of antibiotic resistance. A multimechanistic strategy is needed to design an effective biomaterial with broad-spectrum antibacterial potential. Recent approaches have investigated the fabrication of innately antimicrobial biomedical device surfaces in the hope of making the antibiotic treatment obsolete. Herein, we report a novel fabrication strategy combining antibacterial nitric oxide (NO) with an antibiofilm agent N-acetyl cysteine (NAC) on a polyvinyl chloride surface using polycationic polyethylenimine (PEI) as a linker. The designed biomaterial could release NO for at least 7 days with minimal NO donor leaching under physiological conditions. The proposed surface technology significantly reduced the viability of Gram-negative Escherichia coli (>97%) and Gram-positive Staphylococcus aureus (>99%) bacteria in both adhered and planktonic forms in a 24 h antibacterial assay. The composites also exhibited a significant reduction in biomass and extra polymeric substance accumulation in a dynamic environment over 72 h. Overall, these results indicate that the proposed combination of the NO donor with mucolytic NAC on a polymer surface efficiently resists microbial adhesion and can be used to prevent device-associated biofilm formation.

Medical Device-Associated Biofilm Infections and Multidrug-Resistant Pathogens

Medical devices such as venous catheters (VCs) and urinary catheters (UCs) are widely used in the hospital setting. However, the implantation of these devices is often accompanied by complications. About 60 to 70% of nosocomial infections (NIs) are linked to biofilms. The main complication is the ability of microorganisms to adhere to surfaces and form biofilms which protect them and help them to persist in the host. Indeed, by crossing the skin barrier, the insertion of VC inevitably allows skin flora or accidental environmental contaminants to access the underlying tissues and cause fatal complications like bloodstream infections (BSIs). In fact, 80,000 central venous catheters-BSIs (CVC-BSIs)-mainly occur in intensive care units (ICUs) with a death rate of 12 to 25%. Similarly, catheter-associated urinary tract infections (CA-UTIs) are the most commonlyhospital-acquired infections (HAIs) worldwide.These infections represent up to 40% of NIs.In this review, we present a summary of biofilm formation steps. We provide an overview of two main and important infections in clinical settings linked to medical devices, namely the catheter-asociated bloodstream infections (CA-BSIs) and catheter-associated urinary tract infections (CA-UTIs), and highlight also the most multidrug resistant bacteria implicated in these infections. Furthermore, we draw attention toseveral useful prevention strategies, and advanced antimicrobial and antifouling approaches developed to reduce bacterial colonization on catheter surfaces and the incidence of the catheter-related infections.

S-Nitroso-N-acetylpenicillamine impregnated latex: A new class of barrier contraception for the prevention of intercourse-associated UTIs

Urinary tract infections (UTIs) are some of the most common infections seen in humans, affecting over half of the female population. Though easily and quickly treatable, if gone untreated for too long, UTIs can lead to narrowing of the urethra as well as bladder and kidney infections. Due to the disease potential, it is crucial to mitigate the development of UTIs throughout healthcare. Unfortunately, sexual activity and the use of condoms have been identified as common risk factors for the development of sexually acquired UTIs. Therefore, this study outlines a potential alteration to existing condom technology to decrease the risk of developing sexually acquired UTIs using S-nitroso-N-acetylpenicillamine (SNAP), a nitric oxide (NO) donor. Herein, varying concentrations of SNAP are integrated into commercialized condoms through a facile solvent swelling method. Physical characterization studies showed that 72%-100% of the ultimate tensile strength was maintained with lower SNAP concentrations, validating the modified condom's mechanical integrity. Additionally, the evaluation of room-temperature storage stability via NO release analysis outlined a lack of special storage conditions needed compared to commercial products. Moreover, these samples exhibited >90% relative cell viability and >96% bacterial killing, proving biocompatibility and antimicrobial properties. SNAP-Latex maintains the desired condom durability while demonstrating excellent potential as an effective new contraceptive technology to mitigate the occurrence of sexually acquired UTIs.

Novel surface biochemical modifications of urinary catheters to prevent catheter-associated urinary tract infections

More than 70% of hospital-acquired urinary tract infections are related to urinary catheters, which are commonly used for the treatment of about 20% of hospitalized patients. Urinary catheters are used to drain the bladder if there is an obstruction in the tube that carries urine out of the bladder (urethra). During catheter-associated urinary tract infections, microorganisms rise up in the urinary tract and reach the bladder, and cause infections. Various materials are used to fabricate urinary catheters such as silicone, polyurethane, and latex. These materials allow bacteria and fungi to develop colonies on their inner and outer surfaces, leading to bacteriuria or other infections. Urinary catheters could be modified to exert antibacterial and antifungal effects. Although so many research have been conducted over the past years on the fabrication of antibacterial and antifouling catheters, an ideal catheter needs to be developed for long-term catheterization of more than a month. In this review, we are going to introduce the recent advances in fabricating antibacterial materials to prevent catheter-associated urinary tract infections, such as nanoparticles, antibiotics, chemical compounds, antimicrobial peptides, bacteriophages, and plant extracts.

Structure-activity relationship of drug conjugated polymeric materials against uropathogenic bacteria colonization under in vitro and in vivo settings

The human world has been plagued with different kinds of bacterial infections from time immemorial. The increased development of resistance towards commercial antibiotics has made these bacterial infections an even more critical challenge. Bacteria have modified their mode of interactions with different types of commercial drugs by bringing changes to the receptor proteins or by other resisting mechanisms like drug efflux. Various chemical approaches have been made to date to fight against these smart adapting species. Towards this, we hypothesize chemically modifying the commercial antibacterial drugs in order to deceive the bacteria and destroy the bacterial biomass. In this study, different molecular weight polyethyleneimines are taken and conjugated with some well-known commercial drugs like penicillin and chloramphenicol to explore their antibacterial properties against some of the laboratory and uro-pathogenic strains of Gram-positive and Gram-negative bacteria. A detailed structure-activity relationship of these polymeric prodrug-like materials has been evaluated to determine the optimum formulation. The standardized system not only shows significant ∼90% bacterial killing in liquid broth culture, but also demonstrates promising bacterial inhibition towards biofilm formation for the pathogenic strains on inanimate surfaces like urinary catheters and on an in vivo mouse skin abrasion model. The reported bioactive polymeric materials can be successfully used for widespread therapeutic applications with promising medical relevance.

Resveratrol-Encapsulated Glutathione-Modified Robust Mesoporous Silica Nanoparticles as an Antibacterial and Antibiofilm Coating Agent for Medical Devices

The emergence of various lethal bacterial infections and their adherence to medical devices are major public health concerns. The increased bacterial exposure and titer are accompanied by the inappropriate use of antibiotics that sometimes lead to antibiotic resistance, and therefore, a drug-free antibacterial approach is required. Several nanoparticles (NPs) have been developed as antibacterial and antibiofilm coating agents, which can overcome different drug resistance mechanisms by inhibiting the important processes related to bacterial virulence potential. However, developing safe and biocompatible nanomaterials (NMs) for these applications has remained a major challenge due to their poorly understood mechanism of action. In this work, biogenic silica NPs were modified with glutathione (GSH) to form GSH@SNP (∼80 ± 15 nm) for targeting the bacterial cell surface and biofilm. GSH@SNP was loaded with resveratrol to obtain Res_GSH@SNP (∼124 ± 15 nm) that enhances the antibacterial activity of the NPs against Staphylococcus aureus and Escherichia coli by ∼51 and ∼49%, respectively, compared to GSH@SNP. Res_GSH@SNP is responsible for binding to the bacterial cell surface receptors that interrupt the cell membrane potential, leading to reactive oxygen species (ROS) generation, membrane disruption, and DNA damage and eventually resulting in antibacterial activity. Moreover, the antibiofilm activity of Res_GSH@SNP has been found to result from the interaction of the NPs with the abundant carbohydrates present on the biofilm surface. To check the practical utility of Res_GSH@SNP, these were further evaluated as an antibacterial and antibiofilm coating agent for urinary catheters and were found to be effective even after multiple washes. Res_GSH@SNP has been found to exhibit ∼80 ± 1.4% cytocompatibility toward fibroblast NIH-3T3 cells. Overall, this study is expected to pave the way for the development of biocompatible NP-based coating agents for medical devices.

Characteristics and Key Features of Antimicrobial Materials and Associated Mechanisms for Diverse Applications

Since the Fourth Industrial Revolution, three-dimensional (3D) printing has become a game changer in manufacturing, particularly in bioengineering, integrating complex medical devices and tools with high precision, short operation times, and low cost. Antimicrobial materials are a promising alternative for combating the emergence of unforeseen illnesses and device-related infections. Natural antimicrobial materials, surface-treated biomaterials, and biomaterials incorporated with antimicrobial materials are extensively used to develop 3D-printed products. This review discusses the antimicrobial mechanisms of different materials by providing examples of the most commonly used antimicrobial materials in bioengineering and brief descriptions of their properties and biomedical applications. This review will help researchers to choose suitable antimicrobial agents for developing high-efficiency biomaterials for potential applications in medical devices, packaging materials, biomedical applications, and many more.

Silver nanoparticles with plasma-polymerized hexamethyldisiloxane coating on 3D printed substrates are non-cytotoxic and effective against respiratory pathogens

Due to the emerging resistance of microorganisms and viruses to conventional treatments, the importance of self-disinfecting materials is highly increasing. Such materials could be silver or its nanoparticles (AgNPs), both of which have been studied for their antimicrobial effect. In this study, we compared the biological effects of AgNP coatings with and without a plasma-polymerized hexamethyldisiloxane (ppHMDSO) protective film to smooth silver or copper coatings under three ambient conditions that mimic their potential medical use (dry or wet environments and an environment simulating the human body). The coatings were deposited on 3D printed polylactic acid substrates by DC magnetron sputtering, and their surface morphology was visualized using scanning electron microscopy. Cytotoxicity of the samples was evaluated using human lung epithelial cells A549. Furthermore, antibacterial activity was determined against the Gram-negative pathogenic bacterium Pseudomonas aeruginosa PAO1 and antiviral activity was assessed using human rhinovirus species A/type 2. The obtained results showed that overcoating of AgNPs with ppHMDSO creates the material with antibacterial and antiviral activity and at the same time without a cytotoxic effect for the surrounding tissue cells. These findings suggest that the production of 3D printed substrates coated with a layer of AgNPs-ppHMDSO could have potential applications in the medical field as functional materials.

Emerging evidence-based innovative approaches to control catheter-associated urinary tract infection: a review

Healthcare settings have dramatically advanced the latest medical devices, such as urinary catheters (UC) for infection, prevention, and control (IPC). The continuous or intermittent flow of a warm and conducive (urine) medium in the medical device, the urinary catheter, promotes the formation of biofilms and encrustations, thereby leading to the incidence of CAUTI. Additionally, the absence of an innate immune host response in and around the lumen of the catheter reduces microbial phagocytosis and drug action. Hence, the review comprehensively overviews the challenges posed by CAUTI and associated risks in patients' morbidity and mortality. Also, detailed, up-to-date information on the various strategies that blended/tailored the surface properties of UC to have anti-fouling, biocidal, and anti-adhesive properties to provide an outlook on how they can be better managed with futuristic solutions.

Biosurfactant from Nile Papyrus endophyte with potential antibiofilm activity against global clones of Acinetobacter baumannii

Acinetobacter baumannii is a leading cause of biofilm-associated infections, particularly catheter-related bloodstream infections (CRBSIs) that are mostly recalcitrant to antimicrobial therapy. One approach to reducing the burden of CRBSIs is inhibiting biofilm formation on catheters. Owing to their prodigious microbial diversity, bacterial endophytes might be a valuable source of biosurfactants, which are known for their great capacity to disperse microbial biofilms. With this in mind, our study aimed to screen bacterial endophytes from plants growing on the banks of the River Nile for the production of powerful biosurfactants capable of reducing the ability of A. baumannii to form biofilms on central venous catheters (CVCs). This was tested on multidrug- and extensive drug-resistant (M/XDR) clinical isolates of A. baumannii that belong to high-risk global clones and on a standard strain of A. baumannii ATCC 19606. The drop collapse and oil dispersion assays were employed in screening the cell-free supernatants (CFS) of all endophytes for biosurfactant activity. Of the 44 bacterial endophytes recovered from 10 plants, the CFS of Bacillus amyloliquefaciens Cp24, isolated from Cyperus papyrus, showed the highest biosurfactant activity. The crude biosurfactant extract of Cp24 showed potent antibacterial activity with minimum inhibitory concentrations (MICs) ranging from 0.78 to 1.56 mg/ml. It also showed significant antibiofilm activity (p-value<0.01). Sub-MICs of the extract could reduce biofilm formation by up to 89.59%, while up to 87.3% of the preformed biofilms were eradicated by the MIC. A significant reduction in biofilm formation on CVCs impregnated with sub-MIC of the extract was demonstrated by CV assay and further confirmed by scanning electron microscopy. This was associated with three log₁₀ reductions in adhered bacteria in the viable count assay. GC-MS analysis of the crude biosurfactant extract revealed the presence of several compounds, such as saturated, unsaturated, and epoxy fatty acids, cyclopeptides, and 3-Benzyl-hexahydro-pyrrolo [1, 2-a] pyrazine-1,4-dione, potentially implicated in the potent biosurfactant and antibiofilm activities. In the present study, we report the isolation of a B. amyloliquefaciens endophyte from the plant C. papyrus that produces a biosurfactant with potent antibiofilm activity against MDR/XDR global clones of A. baumannii. The impregnation of CVCs with the biosurfactant was demonstrated to reduce biofilms and, hence, proposed as a potential strategy for reducing CRBSIs.

Mussel-inspired proteins functionalize catheter with antifouling and antibacterial properties

Bacterial adhesion and subsequent biofilm formation on catheter can cause inevitably infection. The development of multifunctional antibacterial coating is a promising strategy to resist the bacteria adhesion and biofilm formation. Herein, a mussel-inspired chimeric protein MZAgP is prepared and employed to modify a variety of polymeric catheters. The MZAgP is composed of mussel-adhesive peptide, zwitterionic peptide, and silver-binding peptide, which can endow catheters with antifouling, bactericidal and biocompatibility performances. Expectedly, negligible biofilm is observed on the MZAgP coated catheters after incubating with bacteria for 120 h. And ignorable hemolysis and cytotoxicity are obtained on coated catheters. In addition, the modified catheters also display persistent antifouling and bacteriostatic properties throughout 168 h under hydrodynamic conditions. Moreover, the coated catheters still remain excellent antifouling and antibacterial properties even after 2 months of storage. This multifunctional coating may be promising as antibacterial and antibiofilm material, and the coated catheters are potential in clinical application.

Nanotechnology Involved in Treating Urinary Tract Infections: An Overview

Considered as the most frequent contaminations that do not require hospitalization, urinary tract infections (UTIs) are largely known to cause significant personal burdens on patients. Although UTIs overall are highly preventable health issues, the recourse to antibiotics as drug treatments for these infections is a worryingly spread approach that should be addressed and gradually overcome in a contemporary, modernized healthcare system. With a virtually alarming global rise of antibiotic resistance overall, nanotechnologies may prove to be the much-needed 'lifebuoy' that will eventually suppress this prejudicial phenomenon. This review aims to present the most promising, currently known nano-solutions, with glimpses on clinical and epidemiological aspects of the UTIs, prospective diagnostic instruments, and non-antibiotic treatments, all of these engulfed in a comprehensive overview.

Eucalyptus-Mediated Synthesized Silver Nanoparticles-Coated Urinary Catheter Inhibits Microbial Migration and Biofilm Formation

Catheter-associated urinary tract infections (CAUTIs) are significant complications among catheterized patients, resulting in increased morbidity, mortality rates, and healthcare costs. Foley urinary catheters coated with synthesized silver nanoparticles (AgNPs) using Eucalyptus camaldulensis leaf extract were developed using a green chemistry principle. In situ-deposited AgNPs with particle size ranging between 20 and 120 nm on the catheter surface were illustrated by scanning electron microscopy. Atomic force microscopy revealed the changes in surface roughness after coating with nanoparticles. The coated catheter could significantly inhibit microbial adhesion and biofilm formation performed in pooled human urine-supplemented media to mimic a microenvironment during infections (p 0.05). AgNPs-coated catheter exhibited broad-spectrum antimicrobial activity against important pathogens, causing CAUTIs with no cytotoxic effects on HeLa cells. A reduction in microbial viability in biofilms was observed under confocal laser scanning microscopy. A catheter bridge model demonstrated complete prevention of Proteus mirabilis migration by the coated catheter. Significant inhibition of ascending motility of Escherichia coli and P. mirabilis along the AgNPs-coated catheter was demonstrated in an in vitro bladder model (p 0.05). The results suggested that the AgNPs-coated urinary catheter could be applied as an alternative strategy to minimize the risk of CAUTIs by preventing bacterial colonization and biofilm formation.

Silicone Foley catheters impregnated with microbial indole derivatives inhibit crystalline biofilm formation by Proteus mirabilis

Proteus mirabilis is a common causative agent for catheter-associated urinary tract infections (CAUTI). The crystalline biofilm formation by P. mirabilis causes catheter encrustation and blockage leading to antibiotic treatment resistance. Thus, biofilm formation inhibition on catheters becomes a promising alternative for conventional antimicrobial-based treatment that is associated with rapid resistance development. Our previous work has demonstrated the in vitro antibiofilm activity of microbial indole derivatives against clinical isolates of P. mirabilis. Accordingly, we aim to evaluate the capacity of silicone Foley catheters (SFC) impregnated with these indole derivatives to resist biofilm formation by P. mirabilis both phenotypically and on the gene expression level. Silicon Foley catheter was impregnated with indole extract recovered from the supernatant of the rhizobacterium Enterobacter sp. Zch127 and the antibiofilm activity was determined against P. mirabilis (ATCC 12435) and clinical isolate P8 cultured in artificial urine. The indole extract at sub-minimum inhibitory concentration (sub-MIC=0.5X MIC) caused a reduction in biofilm formation as exhibited by a 60-70% reduction in biomass and three log₁₀ in adhered bacteria. Results were confirmed by visualization by scanning electron microscope. Moreover, changes in the relative gene expression of the virulence genes confirmed the antibiofilm activity of the indole extract against P. mirabilis. Differential gene expression analysis showed that extract Zch127 at its sub-MIC concentration significantly down-regulated genes associated with swarming activity: umoC, flhC, flhD, flhDC, and mrpA (p< 0.001). In addition, Zch127 extract significantly down-regulated genes associated with polyamine synthesis: speB and glnA (p< 0.001), as well as the luxS gene associated with quorum sensing. Regulatory genes for capsular polysaccharide formation; rcsB and rcsD were not significantly affected by the presence of the indole derivatives. Furthermore, the impregnated catheters and the indole extract showed minimal or no cytotoxic effect against human fibroblast cell lines indicating the safety of this intervention. Thus, the indole-impregnated catheter is proposed to act as a suitable and safe strategy for reducing P. mirabilis CAUTIs.

Recent developments in the use of gold and silver nanoparticles in biomedicine

Gold and silver nanoparticles (NPs) are widely used in the biomedical research both in the therapeutic and the sensing/diagnostics fronts. Both metals share some common optical properties with surface plasmon resonance being the most widely exploited property in therapeutics and diagnostics. Au NPs exhibit excellent light‐to‐heat conversion efficiencies and hence have found applications primarily in precision oncology, while Ag NPs have excellent antibacterial properties which can be harnessed in biomaterials' design. Both metals constitute excellent biosensing platforms owing to their plasmonic properties and are now routinely used in various optical platforms. The utilization of Au and Ag NPs in the COVID‐19 pandemic was rapidly expanded mostly in biosensing and point‐of‐care platforms and to some extent in therapeutics. In this review article, the main physicochemical properties of Au and Ag NPs are discussed with selective examples from the recent literature.

This article is categorized under:

Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease

Diagnostic Tools > In Vitro Nanoparticle‐Based Sensing

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology

Combating Bacterial Biofilm Formation in Urinary Catheter by Green Silver Nanoparticle

Urinary catheters are commonly associated with urinary tract infections. This study aims to inhibit bacterial colonisation and biofilm of urinary tract catheters. Silicon catheter pieces were varnished with green silver nanoparticles (AgNPs) using Pistacia lentiscus mastic to prevent bacterial colonisation. Pomegranate rind extract was used to synthesize AgNPs. AgNPs were characterized by UV-Vis spectroscopy, X-ray crystallography, and transmission electron microscopy (TEM). Results obtained revealed that the size of most AgNPs ranged between 15–25 nm and they took crystallised metal and oxidised forms. The amounts of released silver ions from 1 cm pieces of catheters coated with AgNPs were estimated for five days and ranged between 10.82 and 4.8 µg. AgNPs coated catheters significantly inhibited the colonisation of catheters by antibiotic-resistant clinical Gram-positive (Staphylococcus epidermidis and Staphylococcus aureus) and Gram-negative (Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa) bacteria. AgNPs-varnish was more active against Gram-negative bacteria than Gram-positive bacteria. The significant inhibitory effect of coated catheters lasted for 72 h for both Gram-positive and Gram-negative bacteria. Varnishing catheters with AgNPs may help to prevent bacterial colonisation and infections.

Antibacterial and anti-inflammatory activities of chitosan/copper complex coating on medical catheters: In vitro and in vivo

Copper ions (Cu) grafted chitosan coating was prepared using the pneumatic spraying method on the silicone rubber surface. Coating's surface properties, morphology, composition, Cu releasing behavior, antibacterial, and anti-inflammatory activities are investigated and discussed. Surface properties, composition, and morphology were investigated by scanning electron microscopy (SEM) and contact angle measurements. The antibacterial activity has been tested with Escherichia coli and Staphylococcus aureus suspensions in vitro. Besides, the morphology of the biofilm was inspected with a field emission SEM. To evaluate the anti-inflammatory activity and biosafety of the coating in vivo, the optimized coating samples and control groups were implanted subcutaneously into the back of mice. The bacterial environment model was established by injection of the bacterial suspension. The morphology and bacterial adhered on the surface of catheters and the surrounding tissues were analyzed after 5 days of implantation. As in vitro results, the number of adhered bacterial on the surface of the silicon rubber surface was decreased, and the anti-inflammatory rate was increased by the intensify of the Cu content in chitosan coating. As for in vivo results, after 5 days of implantation, there was no evident inflammation in the surrounding tissues of all catheters in all without the S. aureus injected group. In the injected chitosan/Cu coated group; the inflammation, the number of the adhered bacteria were observed less than other injected samples without Cu; no inflammation were noticeable. Results indicate that the Cu-modified chitosan coating can confer excellent antibacterial and anti-inflammatory activity as applied on medical catheters.

Bio-Inspired Proanthocyanidins from Blueberries’ Surface Coating Prevents Red Blood Cell Agglutination on Urinary Silicon-Based Catheters

Thrombosis can cause the occlusion of implantable medical devices, leading to the rejection of the device and subsequent mortality. Thrombosis is primarily induced by red blood aggregation and coagulation. The administration of anticoagulant drugs is generally used as a treatment to avoid these processes. Adverse effects such as bleeding in the event of an anticoagulant overdose, osteoporosis associated with prolonged use, hypersensitivity, and hives have been reported. New strategies such as biomolecule surface functionalization have recently been studied to overcome these problems. In this study, we report a novel coating composed of polydopamine (PDA) and proanthocyanidins (PACs) from blueberry extract to avoid red blood aggregation in short-term use medical devices such as silicone catheters. We showed that PDA formed stable films on silicone surfaces and PACs could be immobilized on PDA layers using laccase as a catalyst. The PDA–PACs films decreased surface hydrophilicity, increased surface roughness, and decreased plasma protein adsorption. The films were stable in phosphate buffer saline (PBS) and cell culture media. Furthermore, red blood cell adsorption and aggregation decreased. These effects are attributed to changes in the membrane fluidity that influences adhesion, the steric hindrance of the layers, and the low adsorption of plasma proteins on the PAC layer.

Hyaluronic Acid-Silver Nanocomposites and Their Biomedical Applications: A Review

For the last years scientific community has witnessed a rapid development of novel types of biomaterials, which properties made them applicable in numerous fields of medicine. Although nanosilver, well-known for its antimicrobial, anti-angiogenic, anti-inflammatory and anticancer activities, as well as hyaluronic acid, a natural polysaccharide playing a vital role in the modulation of tissue repair, signal transduction, angiogenesis, cell motility and cancer metastasis, are both thoroughly described in the literature, their complexes are still a novel topic. In this review we introduce the most recent research about the synthesis, properties, and potential applications of HA-nanosilver composites. We also make an attempt to explain the variety of mechanisms involved in their action. Finally, we present biocompatible and biodegradable complexes with bactericidal activity and low cytotoxicity, which properties suggest their suitability for the prophylaxis and therapy of chronic wounds, as well as analgetic therapies, anticancer strategies and the detection of chemical substances and malignant cells. Cited studies reveal that the usage of hyaluronic acid-silver nanocomposites appears to be efficient and safe in clinical practice.

Current approaches for the exploration of antimicrobial activities of nanoparticles

Infectious diseases of bacterial and viral origins contribute to substantial mortality worldwide. Collaborative efforts have been underway between academia and the industry to develop technologies for a more effective treatment for such diseases. Due to their utility in various industrial applications, nanoparticles (NPs) offer promising potential as antimicrobial agents against bacterial and viral infections. NPs have been established to possess potent antimicrobial activities against various types of pathogens due to their unique characteristics and cell-damaging ability through several mechanisms. The recently accepted antimicrobial mechanisms possessed by NPs include metal ion release, oxidative stress induction, and non-oxidative mechanisms. Another merit of NPs lies in the low likelihood of the development of microbial tolerance towards NPs, given the multiple simultaneous mechanisms of action against the pathogens targeting numerous gene mutations in these pathogens. Moreover, NPs provide a fascinating opportunity to curb microbial growth before infections: this outstanding feature has led to their utilization as active antimicrobial agents in different industrial applications, e.g. the coating of medical devices, incorporation in food packaging, promoting wound healing and encapsulation with other potential materials for wastewater treatment. This review discusses the progress and achievements in the antimicrobial applications of NPs, factors contributing to their actions, mechanisms underlying their efficiency, and risks of their applications, including the antimicrobial action of metal nanoclusters (NCs). The review concludes with a discussion of the restrictions on present studies and future prospects of nanotechnology-based NPs development.

Bioengineered phytomolecules-capped silver nanoparticles using Carissa carandas leaf extract to embed on to urinary catheter to combat UTI pathogens

Rising incidents of urinary tract infections (UTIs) among catheterized patients is a noteworthy problem in clinic due to their colonization of uropathogens on abiotic surfaces. Herein, we have examined the surface modification of urinary catheter by embedding with eco-friendly synthesized phytomolecules-capped silver nanoparticles (AgNPs) to prevent the invasion and colonization of uropathogens. The preliminary confirmation of AgNPs production in the reaction mixture was witnessed by the colour change and surface resonance plasmon (SRP) band at 410nm by UV–visible spectroscopy. The morphology, size, crystalline nature, and elemental composition of attained AgNPs were further confirmed by the transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD) technique, Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The functional groups of AgNPs with stabilization/capped phytochemicals were detected by Fourier-transform infrared spectroscopy (FTIR). Further, antibiofilm activity of synthesized AgNPs against biofilm producers such as Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were determined by viability assays and micrographically. AgNPs coated and coating-free catheters performed to treat with bacterial pathogen to analyze the mat formation and disruption of biofilm formation. Synergistic effect of AgNPs with antibiotic reveals that it can enhance the activity of antibiotics, AgNPs coated catheter revealed that, it has potential antimicrobial activity and antibiofilm activity. In summary, C. carandas leaf extract mediated synthesized AgNPs will open a new avenue and a promising template to embed on urinary catheter to control clinical pathogens.

Varied-shaped gold nanoparticles with nanogram killing efficiency as potential antimicrobial surface coatings for the medical devices

Medical device-associated infections are a serious medical threat, particularly for patients with impaired mobility and/or advanced age. Despite a variety of antimicrobial coatings for medical devices being explored to date, only a limited number have been introduced for clinical use. Research into new bactericidal agents with the ability to eradicate pathogens, limit biofilm formation, and exhibit satisfactory biocompatibility, is therefore necessary and urgent. In this study, a series of varied-morphology gold nanoparticles in shapes of rods, peanuts, stars and spherical-like, porous ones with potent antibacterial activity were synthesized and thoroughly tested against spectrum of Candida albicans, Pseudomonas aeruginosa, Staphylococcus aureus clinical strains, as well as spectrum of uropathogenic Escherichia coli isolates. The optimization of gold nanoparticles synthesis allowed to develop nanomaterials, which are proved to be significantly more potent against tested microbes compared with the gold nanoformulations reported to date. Notably, their antimicrobial spectrum includes strains with different drug resistance mechanisms. Facile and cost-efficient synthesis of gold nanoparticles, remarkable bactericidal efficiency at nanogram doses, and low toxicity, underline their potential for development as a new coatings, as indicated by the example of urological catheters. The presented research fills a gap in microbial studies of non-spherical gold nanoparticles for the development of antimicrobial coatings targeting multidrug-resistant pathogens responsible for device-associated nosocomial infections.

Exploitation of Antimicrobial Nanoparticles and Their Applications in Biomedical Engineering

Antibiotic resistance is a major threat to public health, which contributes largely to increased mortality rates and costs in hospitals. The severity and widespread nature of antibiotic resistance result in limited treatments to effectively combat antibiotic-resistant pathogens. Nanoparticles have different or enhanced properties in contrast to their bulk material, including antimicrobial efficacy towards a broad range of microorganisms. Their beneficial properties can be utilised in various bioengineering technologies. Thus, antimicrobial nanoparticles may provide an alternative to challenge antibiotic resistance. Currently, nanoparticles have been incorporated into materials, such as fibres, glass and paints. However, more research is required to elucidate the mechanisms of action fully and to advance biomedical applications further. This paper reviews the antimicrobial efficacies and the intrinsic properties of different metallic nanoparticles, their potential mechanisms of action against certain types of harmful pathogens and how these properties may be utilised in biomedical and healthcare products with the aim to reduce cross contaminations, disease transmissions and usage of antibiotics.

In Situ Deposition of Green Silver Nanoparticles on Urinary Catheters under Photo-Irradiation for Antibacterial Properties

Urinary tract infections, especially catheter-associated urinary tract infections (CAUTIs), are the most common type of nosocomial infections. Patients with chronic indwelling urinary catheters have a higher risk of infection due to biofilm formation on the urinary catheter surface. Therefore, in this work, a novel, cost-effective antimicrobial urinary catheter was developed using green technology. Silver nanoparticles (AgNPs) synthesized from Mon Thong durian rind waste were used as an antimicrobial agent for the prevention of infection. Flavonoids, phenolic compounds, and glucose extracted from durian rind were used as a reducing agent to reduce the Ag+ dissolved in AgNO3 solution to form non-aggregated AgNPs under light irradiation. The AgNPs were simultaneously synthesized and coated on the inner and outer surfaces of silicone indwelling urinary catheters using the dip coating method. The results showed that the antimicrobial urinary catheter fabricated using a 0.3 mM AgNO3 concentration and 48 h coating time gave the highest antibacterial activity. The as-prepared spherical AgNPs with an average diameter of 9.1 ± 0.4 nm formed on catheter surfaces in a monolayer approximately 1.3 µm thick corresponding to a 0.712 mg/cm2 silver content. The AgNP layer was found to damage and almost completely inhibit the growth of Escherichia coli cells with antibacterial activity by 91%, equivalent to the commercial, high-price antimicrobial urinary catheter. The cumulative amount of silver released from the coated catheter through artificial urine over 10 days was about 0.040 µg/mL, which is less than the silver content that causes tissue and organ toxicity at 44 µg/mL. Thus, we concluded that the developed antimicrobial urinary catheter was useful in reducing the risk of infectious complications in patients with indwelling catheters.

Promising Roles of Alternative Medicine and Plant-Based Nanotechnology as Remedies for Urinary Tract Infections

Urinary tract infections (UTIs) are considered to be the most common infections worldwide, having an incidence rate of 40-60% in women. Moreover, the prevalence of this disorder in adult women is 30 times more than in men. UTIs are usually found in many hospitals and clinical practice; as disorders, they are complicated and uncomplicated; in uncomplicated cases, there is no structural or functional abnormality in the urogenital tract. However, obstruction, retention of urine flow and use of catheters increase the complexity. There are several bacteria (e.g., E. coli, Klebsiella pneumoniae, Proteus vulgaris, etc.) successfully residing in the tract. The diagnosis must not only be accurate but rapid, so early detection is an important step in the control of UTIs caused by uropathogens. The treatment of UTIs includes appropriate antimicrobial therapy to control the infection and kill the causal microbes inside the body. A long-time usage of antibiotics has resulted in multidrug resistance causing an impediment in treatment. Thus, alternative, combinatorial medication approaches have given some hope. Available treatments considered Homeopathic, Ayurvedic, Unani, and other herbal-based drugs. There are new upcoming roles of nanoparticles in combating UTIs which needs further validation. The role of medicinal plant-based nanotechnology approaches has shown promising results. Therefore, there must be active research in phyto-based therapies of UTIs, such as Ayurvedic Biology.

Antifouling and antimicrobial polyethersulfone/hyperbranched polyester-amide/Ag composite

This study provided a facile approach for the development of antifouling and antibacterial polyethersulfone (PES) composite film. Mainly, hyperbranched polyester-amide (PESAM) was used as both the reducing and capping agent for the in situ formation of AgNPs. The nanoparticles were intensively investigated using Fourier transform infrared spectroscopy (FTIR), ultra-violet spectroscopy (UV-vis), scanning and transmission electron microscopy (SEM & TEM) and X-ray diffraction (XRD). AgNPs were narrowly distributed with an average particle size of about 6 nm. PESAM was mixed with PES to realize free-standing film using the phase inversion method. The inclusion of PESAM in the composite film significantly improved hydrophilicity as confirmed by the contact angle measurements. Furthermore, SEM and EDX investigations confirmed that PESAM induced the in situ formation of AgNPs not only on the film surface but also inside its macro-voids. The composite film (PES/PESAM/Ag) displayed significant antibacterial potential against Gram positive and Gram negative bacteria. Overall, the described method paves the way towards development of advanced PES composite films with antimicrobial properties for broad application areas that include desalination membranes or active packaging materials.

This study provided a facile approach for the development of antifouling and antibacterial polyethersulfone (PES) composite film.