Background/Objectives: Biofilm-related infections represent a major concern in clinical practice because of their poor responsiveness to standard antimicrobial treatments. Over the past decade, many efforts have been made to identify new compounds capable of inhibiting this particularly resistant form of bacterial life. Although several compounds have shown interesting anti-biofilm properties, none have reached the clinic. Methods: In the present work, we describe the synthesis and biological assessment as anti-biofilm agents, of a novel library of twenty-one imidazo[2,1-b][1,3,4]thiadiazol-2-yl]-1H-pyrrolo[2,3-b]pyridines. Results: The newly synthesized compounds were in vitro evaluated for their ability to prevent biofilm formation and to eradicate established biofilms in Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 15442. Additionally, the most potent compounds, 9g and 9u, were in vivo assayed for their safety profile and the anti-infective effect in a Galleria mellonella model. Conclusions: Derivatives 9g, 9i, 9n, 9q and 9u proved to be potent inhibitors of S. aureus biofilm showing BIC50 values lower than 15 µg/mL. Noteworthy, the in vivo results revealed the promising protective properties of compound 9u in the early stage of staphylococcal infection.

Oxidative stress and bacterial infections can lead to compromised tissue regeneration in chronic wounds. Since traditional treatments are often ineffective, in this study a hydrogel based on two inulin derivatives, called dcINU-TA-NS, was design as multifunctional wound dressing platform with in vitro Anti-Staphylococcus aureus and antioxidant performance. Thanks to double crosslinking the hydrogel is characterized by modulable viscoelastic properties: dynamic interactions, based on the boronic ester bonds between inulin functionalized with 3-aminophenyl boronic acid (INU-APBA) and tannic acid (TA), ensure adaptability and adhesion to the injured site and ease of application; afterward a covalent crosslinking is obtained by UV cross-linking of the methacrylic groups of methacrylate inulin (INU-MA), giving greater persistence to the hydrogel at the site of interest. Thanks to the presence of TA, the hydrogel demonstrated a strong in vitro antioxidant activity, which lasts up to a week and is essential for reducing oxidative stress and promoting healing. Furthermore, the sensitivity of the boronic bonds to acidic pH allows for increased release of TA in an inflammatory environment. To ensure antibacterial efficacy, we introduced manganese dioxide nanosheets (NS), which exhibit photothermal activity upon NIR irradiation, making the polysaccharide platform thereby enabling antibacterial photothermal therapy (PTTA), which demonstrated in vitro activity exclusively against Staphylococcus aureus after a single irradiation. The photostability of the hydrogel allows for multiple irradiation cycles to increase effectiveness. Cytocompatibility was assessed on FD-MSC and RAW 264.7 cells.

In this study, seven Pleosporaceae strains isolated from the seagrass Posidonia oceanica and the jellyfish Pelagia noctiluca in the central Tyrrhenian Sea were characterized using a polyphasic approach (morpho-physiological, molecular, and phylogenetic analyses). Based on multi-locus phylogenetic inference and morphological characters, a new species, Tamaricicola fenicei sp. nov. was proposed. Multi-locus phylogenetic analyses, using the nuclear ribosomal regions of DNA (nrITS1-nr5.8S-nrITS2, nrLSU, and nrSSU) as well as the rpb2 and tef-1α gene sequences, strongly supported the new taxon. The phylogenetic inference, estimated using Maximum Likelihood and Bayesian Inference, clearly indicates that Tamaricicola fenicei sp. nov. forms a distinct clade within the monospecific genus Tamaricicola. The antimicrobial activity of the chloroformic and butanolic extracts from malt agar cultures of the new species exhibited interesting antiviral and antibiofilm properties. In particular, a MIC of 3.0 µg/mL was observed against the Echovirus E11 in Vero-76 cells; moreover, a biofilm BIC50 reduction at 53 µg/mL was observed against Staphylococcus aureus ATCC 25923.

A quaternized derivative of gellan gum (GG-EDA-GTMAC) was synthesized and employed to develop injectable and printable nanocomposite hydrogels incorporating silver nanoparticles (AgNPs). The specific physicochemical properties of the GG-EDA-GTMAC derivative enabled efficient synthesis and stabilization of AgNPs within the hydrogel matrix. The hydrogels demonstrated remarkable stability, resisting hydrolytic degradation with only similar to 20 % weight loss over 14 days of incubation, and exhibited controlled silver release. A comprehensive study of the properties of nanocomposite hydrogels was conducted to evaluate their ease of formulation, injectability, safety, and broad-spectrum antimicrobial effectiveness. Rheological characterization highlighted shear-thinning and self-healing behavior, as well as sensitivity to ionic strength, ensuring good injectability and shape maintenance after injection. These properties enabled the successful 3D printing of the hydrogels into structures with various shapes and sizes, demonstrating excellent model fidelity and structural stability. Biological and microbiological evaluations confirmed cytocompatibility, hemocompatibility, and strong antimicrobial activity against Gram-positive and Gram-negative bacteria, Candida albicans, and protozoa, highlighting the multifunctional antimicrobial potential of the system. Collectively, these findings suggest the developed hydrogels as promising candidates for the treatment of wounds infected by a wide range of pathogens, including both bacterial and protozoan agents.

Streptomyces coelicolor spent fermentation medium was used to produce biogenic silver nanoparticles (ScoAgNPs) which were characterized for their size, morphology, stability, structure, macromolecular composition, and bioactivities. In particular, ATR-FTIR spectroscopy revealed the presence of lipids, nucleic acids, and proteins in ScoAgNPs. Differential shotgun proteomic analysis - comparing the ScoAgNP protein content with the S. coelicolor secretome - identified proteins accumulated in the biogenic nanomaterial. Bioinformatic analysis revealed their binding domains for nucleotides, carbon compounds, and metal compounds, as well as their predicted molecular functions. Additionally, in vitro assays revealed ScoAgNPs antimicrobial, antibiofilm, anticancer, and seed germination-promoting activities. These properties suggest that the ScoAgNPs could serve as promising bionanotechnological tools with applications in biomedicine and agriculture. Additionally, the identification of associated proteins provides novel insights into the biomolecular mechanisms underlying AgNP biogenesis, also paving the way for rational strategies aimed at optimizing production and enhancing bio-functionality.

Nanofibrous electrospun scaffolds were produced by electrospinning using polybutylene succinate (PBS), a biodegradable and biocompatible polymer, loaded with a poorly water-soluble antibacterial agent, ciprofloxacin (CPX). The morphological analysis revealed that the PBS-CPX 5 % scaffold possessed smaller average fiber sizes compared to the PBS-CPX 20 % scaffold, attributed to the higher CPX concentration. MicroCT scans demonstrated uniform morphology within the scaffold structures. Wettability studies indicated the membrane-like behavior of the scaffolds, facilitating the passage of blood components while filtering red blood cells, fostering an environment conducive to wound healing, combined with their non-hemolytic property. Dissolution studies revealed distinct release profiles, with PBS-CPX 20 % exhibiting prolonged modified release, whereas PBS-CPX 5 % facilitated the enhanced systemic circulation of CPX. Ex-vivo permeation studies on porcine skin demonstrated increased CPX permeation compared to raw CPX, showcasing the scaffold's potential for enhanced transdermal absorption. As predicted, scaffolds demonstrated great cytocompatibility, with cell viability above 90 %. Additionally, both scaffolds exhibited potent antibiofilm efficacy against Staphylococcus aureus and Pseudomonas aeruginosa biofilms, significantly reducing viable bacterial counts compared to controls. Overall, these findings highlight the potential of the developed scaffolds as promising drug delivery systems (DDSs) for wound healing and skin infection treatment, offering controlled drug release, enhanced transdermal absorption, and effective antibacterial activity, thereby addressing critical challenges in wound management.

The increasingly complex treatment of bacterial infections, and its relevance in the clinical setting, requires the development of innovative strategies to improve patients' quality of life. In this context, polymeric microparticles represents a versatile drug delivery system (DDS) capable of improving the antibiotics' efficacy in the treatments, by loading drugs while modifying their release profile. In this study we aimed to produce polymeric microparticles by electrospraying using Poly-Butyl-Succinate (PBS), a biodegradable and biocompatible polyester. This versatile and easy-to-use technique enabled the incorporation of the poorly water-soluble Ciprofloxacin (CPX) into the polymer matrix. CPX is a fluoroquinolone antibiotic, inhibiting bacterial replication and effectively treating various infections. PBS is a well-known water-insoluble polymer with tuneable chemical-physical properties, also used for tissue regeneration and wound healing applications. An ex-vivo permeation study on porcine skin, serving as a model for human skin, was performed to assess potential enhancement in drug permeation. The microparticles were characterized by means of different techniques (SEM-EDX, XRD, ATR-FTIR, DSC), and their degradation rate was tested in DPBS and human plasma. Moreover, the as-produced DDS enabled the sustained release of CPX for several days, which proved effective against S. aureus and P. aeruginosa and also against a reference group of bacteria of skin microbiota often involved in pathological processes that make wounds chronic and difficult to heal. MIC and MBC assays were conducted using different culture media. Effective antibacterial activity was observed, along with inhibition of P. aeruginosa biofilm formation at sub-MIC concentrations.

Several new synthesized 4-cinnamamido- and 2-phenoxyacedamido-1H-pyrazol-5-yl)benzamides were obtained by two multi step different synthetic routes in order to maximize their yield. The new derivatives were screened to determinate the antiproliferative, antimicrobial and antibiofilm activity. The biological results showed how, respect to the antiproliferative and antimicrobial activities, the compounds showed a low to missing activity. Different are the results obtained with respect to the antibiofilm activity, especially towards Candida albicans. Most of the synthesized compounds showed a good percentage inhibition of biofilm formation ranging from 60 to 73% with a Biofilm Inhibition Concentration 50% (BIC50) from 0.13 to 0.01 µM. Among the synthesized the ethyl 5-(4-(2-(4-chlorophenoxy)acetamido)benzamido)-1-methyl-1H-pyrazole-4-carboxylate (27c) resulted the most active with a BIC50 of 0.01 µM. According to the result obtained, such compound could be considered a lead subject of further studies to obtain novel and more effective antibiofilm agents against C. albicans infections.

Biofilm-associated infections pose significant challenges in healthcare settings due to their resistance to conventional antimicrobial therapies. In the last decade, the marine environment has been a precious source of bioactive molecules, including numerous derivatives with antibiofilm activity. In this study, we reported the synthesis and the biological evaluation of a new series of twenty-two thiadiazopyrimidinone derivatives obtained by using a hybridization approach combining relevant chemical features of two important classes of marine compounds: nortopsentin analogues and Essramycin derivatives. The synthesized compounds were in vitro tested for their ability to inhibit biofilm formation and to disrupt mature biofilm in various bacterial strains. Among the tested compounds, derivative 8j exhibited remarkable dispersal activity against preformed biofilms of relevant Gram-positive and Gram-negative pathogens, as well as towards the fungus Candida albicans, showing BIC50 values ranging from 17 to 40 µg/mL. Furthermore, compound 8j was in vivo assayed for its toxicity and the anti-infective effect in a Galleria mellonella model. The results revealed a promising combination of anti-infective properties and a favorable toxicity profile for the treatment of severe chronic biofilm-mediated infections.

A thermoresponsive and mucoadhesive hydrogel has been developed for the local delivery of a novel anti-Candida peptide. This antimicrobial peptide was custom-designed and synthesized, utilizing a natural peptide identified in the hemolymph of the freshwater crayfish Procambarus clarkii as a molecular scaffold. The hydrogel, fabricated from a xanthan gum/poly-N-isopropylacrylamide graft copolymer, demonstrates temperature-dependent viscoelastic properties and a pseudoplastic behaviour, making it suitable for potential administration in various tissues. Moreover, the high stability of the hydrogel (about 9 % weight loss after 24 h of incubation) in physiological fluids as well as its mucoadhesive properties indicate that it could withstand in the application site long enough to perform its intended function. Furthermore, the good cytocompatibility of the hydrogel and the peptide's release profile (approximately 90 % release within the first 24 h), coupled with its efficacy in inhibiting fungal growth (logarithmic reduction of 1.08 compared to the control), validates the prospective application of the formulation in managing mucosal and superficial skin C. albicans infections. This not only addresses concerns related to drug resistance but also establishes the hydrogel as a versatile platform for advanced drug delivery systems aimed at circumventing systemic administration of antifungal drugs for the treatment of superficial skin and mucosal candidiasis.

In this study, hydrogels were produced using a Schiff base reaction between two hyaluronic acid derivatives: one containing aldehyde groups (HA-Ald) and the other holding a diethylenetriamine with terminal amino groups (HA-DETA). The DETA portion promotes the in situ growth, complexation, and stabilization of silver nanoparticles (AgNPs), eliminating the need for external reducing agents. The reaction between HA-DETA and HA-Ald leads to the formation of imine bonds, which results in dynamically pH-responsive cross-linking. While the DETA capping ability helped in embedding the AgNPs, the on/off pH environmental responsivity of the hydrogel allows for a controlled and on-demand release of the drug, mainly when bacterial infections cause pH variation of the wound bed. The injectable hydrogels resulted in being highly compatible in contact with blood red cells, fibroblasts, and keratinocytes and capable of having a proliferative effect on an in vitro wound scratch model. The pH-responsive hydrogels showed proper antibacterial activity againstPseudomonas aeruginosaandStaphylococcus aureus, common bacterial strains presented in wound infections. Finally, in vivo wound model studies demonstrated an overall speeding up in the wound healing rate and advanced wound conditions in the experimental group treated with the hydrogels compared to control samples.

The demand for new molecules to counter bacterial resistance to antibiotics and tumor cell resistance is increasingly pressing. The Mediterranean seagrass Posidonia oceanica is considered a promising source of new bioactive molecules. Polypeptide-enriched fractions of rhizomes and green leaves of the seagrass were tested against Gram-positive (e.g., Staphylococcus aureus, Enterococcus faecalis) and Gram-negative bacteria (e.g., Pseudomonas aeruginosa, Escherichia coli), as well as towards the yeast Candida albicans. The aforementioned extracts showed indicative MIC values, ranging from 1.61 μg/mL to 7.5 μg/mL, against the selected pathogens. Peptide fractions were further analyzed through a high-resolution mass spectrometry and database search, which identified nine novel peptides. Some discovered peptides and their derivatives were chemically synthesized and tested in vitro. The assays identified two synthetic peptides, derived from green leaves and rhizomes of P. oceanica, which revealed interesting antibiofilm activity towards S. aureus, E. coli, and P. aeruginosa (BIC50 equal to 17.7 μg/mL and 70.7 μg/mL). In addition, the natural and derivative peptides were also tested for potential cytotoxic and apoptosis-promoting effects on HepG2 cells, derived from human hepatocellular carcinomas. One natural and two synthetic peptides were proven to be effective against the "in vitro" liver cancer cell model. These novel peptides could be considered a good chemical platform for developing potential therapeutics.

In this work a synthetic protocol for the functionalization of hyaluronic acid with diethylenetriamine (DETA) was standardized. HA-DETA derivatives were characterized by NMR and proton carbon correlation analysis HSQC and HMBC to confirm chemical structure. A selected derivative was used to set up a green fabrication procedure for HA-DETA capped silver nanoparticles with the aim to achieve a polymeric based coating with potential application in the treatment of medical devices associated infections. Data from UV-visible spectroscopy, electron scanning and transmission microscope (STEM), photoelectric spectroscopy (XPS) and rheological characterization were combined to characterize the HA-DETA/Ag nanocomposites. HA-DETA stabilized Ag nanoparticles (10-30 nm) were obtained through an UV accelerated production. The viability of MC3T3-E1 was analyzed with the aim of designing a cytocompatible antimicrobial coating. Antibacterial and antibiofilm activity of HA-DETA/Ag nanocomposites have been tested in vitro against Staphylococcus aureus and Pseudomonas aeruginosa both in culture plates than on titanium specimens.

The development of wound dressings with combined antioxidant, antibacterial and tissue adhesion functions has been a difficult medical task for the treatment of wound infections. We synthetized a dopamine and PEG functionalized Gellan Gum (GG) to produce an injectable hydrogel with radical scavenging activity having both specific and aspecific antibiotic/antimicrobial properties. Using starting GG with different molecular weights, we obtained two derivatives that have been used to prepare the gel precursor dispersion, that undergoes gelation in the presence of colistin and dried microparticles (MPs) functionalized on the surface with polydopamine (pDA). Both were used to dope the hydrogel, increase the radical scavenger activity and impart near-infrared light (NIR) responsiveness. Indeed, with an irradiation of 810 nm, the incorporated microparticles exhibit photothermal transformation properties and improve the release of antibiotics on demand. The combination of photothermal and antibiotic therapy with synergistic antibacterial action acts on Pseudomonas aeruginosa and leads to a bactericidal effect in a few hours, while on Staphylococcus aureus there is an effect of inhibition of growth over time due only to the hyperthermic effect. We believe this study provides a promising method for fabricating a multifunctional injectable hydrogel for the potential treatment of infected skin wounds.

The defense system of freshwater crayfish Procambarus clarkii as a diversified source of bioactive molecules with antimicrobial properties was studied. Antimicrobial activity of two polypeptide-enriched extracts obtained from hemocytes and hemolymph of P. clarkii were assessed against Gram positive (Staphylococcus aureus, Enterococcus faecalis) and Gram negative (Pseudomonas aeruginosa, Escherichia coli) bacteria and toward the yeast Candida albicans. The two peptide fractions showed interesting MIC values (ranging from 11 to 700 μg/mL) against all tested pathogens. Polypeptide-enriched extracts were further investigated using a high-resolution mass spectrometry and database search and 14 novel peptides were identified. Some peptides and their derivatives were chemically synthesized and tested in vitro against the bacterial and yeast pathogens. The analysis identified a synthetic derivative peptide, which showed an interesting antifungal (MIC and MFC equal to 31.2 μg/mL and 62.5 μg/mL, respectively) and antibiofilm (BIC50 equal to 23.2 μg/mL) activities against Candida albicans and a low toxicity in human cells.

The much-publicised increased resistance of pathogenic bacteria to conventional antibiotics has focused research effort on the characterization of new antimicrobial drugs. In this context, antimicrobial peptides (AMPs) extracted from animals are considered a promising alternative to conventional antibiotics. In recent years, freshwater crayfish species have emerged as an important source of bioactive compounds. In fact, these invertebrates rely on an innate immune system based on cellular responses and on the production of important effectors in the haemolymph, such as AMPs, which are produced and stored in granules in haemocytes and released after stimulation. These effectors are active against both Gram-positive and Gram-negative bacteria. In this review, we summarise the recent progress on AMPs isolated from the several species of freshwater crayfish and their prospects for future pharmaceutical applications to combat infectious agents.

This study reports the first enzymatic synthesis leading to several oligomer analogues of poly[3-(3,4-dihydroxyphenyl)glyceric acid]. This biopolymer, extracted from plants of the Boraginaceae family has shown a wide spectrum of pharmacological properties, including antimicrobial activity. Enzymatic ring opening polymerization of 2-methoxycarbonyl-3-(3,4-dibenzyloxyphenyl)oxirane (MDBPO) using lipase from Candida rugosa leads to formation of poly[2-methoxycarbonyl-3-(3,4-dibenzyloxyphenyl)oxirane] (PMDBPO), with a degree of polymerization up to 5. Catalytic debenzylation of PMDBPO using H2 on Pd/C yields poly[2-methoxycarbonyl-3-(3,4-dihydroxyphenyl)oxirane] (PMDHPO) without loss in molecular mass. Antibacterial assessment of natural polyethers from different species of Boraginaceae family Symhytum asperum, S. caucasicum,S. grandiflorum, Anchusa italica, Cynoglossum officinale, and synthetic polymers, poly[2-methoxycarbonyl-3-(3,4-dimethoxyphenyl)oxirane (PMDMPO) and PMDHPO, reveals that only the synthetic analogue produced in this study (PMDHPO) exhibits a promising antimicrobial activity against pathogenic strains S.aureus ATCC 25923 and E.coli ATCC 25922 the minimum inhibitory concentration (MIC) being 100 µg/mL.

Helianthemum lippii is a perennial shrubby plant growing in the sandy environments of Italy, Mediterranean countries of North Africa and Middle East. H. lippii is used in traditional medicine but there are very few reports referring to the phytochemical characterization, the ethnopharmacology, and the biological activity of H. lippii. The goal of this study was to determine the phytochemical composition of different H. lippii extracts, cold (CME) and hot (HME) methanol, cold (CPEE) and hot (HPEE) petroleum ether, as well as to evaluate their anticancer and antimicrobial activities and biofilm formation reduction. Fifty-fours phytocompounds have been determined by HPLC-UV-ESI-QTOF-MS analysis. All the four extracts reduced the viability of human MDA-MB231 and HCT116 cells, being cold and hot methanol extracts the most effective. The antimicrobial activity against S. aureus, P. aeruginosa, E. faecalis, E. coli, C. albicans was also evaluated. Data showed the greater susceptibility of S. aureus to hot methanolic extract. Concerning antifungal activity, C. albicans resulted more susceptible to petroleum ether. Moreover, some of the samples exhibited a good antibiofilm activity both on immature and on mature biofilms. The four extracts showed interesting antimicrobial and cytotoxic activities and can be considered good candidates for new therapeutic applications

The development of biomedical systems with antimicrobial and antibiofilm properties is a difficult medical task for preventing bacterial adhesion and growth on implanted devices. In this work, a fibrillar scaffold was produced by electrospinning a polymeric organic dispersion of polylactic acid (PLA) and poly(α,β-(N-(3,4-dihydroxyphenethyl)-L-aspartamide-co-α,β-N-(2-hydroxyethyl)-L-aspartamide) (PDAEA). The pendant catechol groups of PDAEA were used to reduce silver ions in situ and produce silver nanoparticles onto the surface of the electrospun fibers through a simple and reproducible procedure. The morphological and physicochemical characterization of the obtained scaffolds were studied and compared with virgin PLA electrospun sample. Antibiofilm properties against Pseudomonas aeruginosa, used as a biofilm-forming pathogen model, were also studied on planar and tubular scaffolds. These last were fabricated as a proof of concept to demonstrate the possibility to obtain antimicrobial devices with different shape and dimension potentially useful for different biomedical applications. The results suggest a promising approach for the development of antimicrobial and antibiofilm scaffolds.

Here we reported the fabrication of an electrospun membrane based on a hyaluronic acid derivative (HA-EDA) to be used as a bandage for the potential treatment of chronic wounds. The membrane, loaded with graphene oxide (GO) and ciprofloxacin, showed photothermal properties and light-triggered drug release when irradiated with a near-infrared (NIR) laser beam. Free amino groups of HA-EDA derivative allowed autocrosslinking of the electrospun membrane; thus, a substantial enhancement in the hydrolytic resistance of the patch was obtained. In vitro antibacterial activity studies performed on Staphylococcus aureus and Pseudomonas aeruginosa revealed that such electrospun membranes, due to the synergistic effect of the antibiotic and NIR-mediated hyperthermia, reduced the viability of both pathogens. Specific in vitro experiment demonstrated also that is possible to disrupt, through laser irradiation, the biofilms formed onto the membrane.