Submit to Molecules Review for Molecules Propose a Special Issue

Journal Menu

Journal Browser

► Journal Browser

Novel Biologically Active Molecules, Biomaterials and Nanoparticles for the Microbial Biofilm Control in Human Medicine

Special Issue Editors
Special Issue Information
Keywords
Benefits of Publishing in a Special Issue
Published Papers

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Medicinal Chemistry".

Deadline for manuscript submissions: closed (31 March 2021) | Viewed by 55611

Share This Special Issue

Special Issue Editors

Dr. Rossella Grande

E-Mail Website
Guest Editor

Department of Pharmacy, University “G. d'Annunzio” of Chieti-Pescara, 66100 Chieti, Italy
Interests: microbial biofilms; Helicobacter pylori; Lactobacillus reuteri; outer membrane vesicles; extracellular DNA; antimicrobial/antibiofilm activity; human microbiome; probiotics; prebiotics and symbiotics
Special Issues, Collections and Topics in MDPI journals

Dr. Simone Carradori

E-Mail Website
Guest Editor

Department of Pharmacy, “G. d’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy
Interests: natural compounds; medicinal chemistry; food chemistry; antioxidants; antimicrobials; anti-inflammatory; anticancer; extracion; bioactive compounds; nutrceutical; well-being; food supplement; functional food
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Microbial biofilms are complex structures formed by cells embedded in an extracellular polymeric substance (EPS) matrix, a mixture of macromolecules such as exopolysaccharides; proteins; extracellular DNA; and, in some cases, outer membrane vesicles. EPS composition may differ with bacterial strains, culture conditions, and biofilm age. Biofilm formation ensures antibiotic tolerance and protection from the host immune system, making microbial biofilms difficult to eradicate. Biofilms are responsible for chronic infections, and biofilms developed by a wide range of microorganisms are considered a “virulence factor”. The variability in the composition of the biofilm matrix and in biofilm development as well as tolerance versus the antimicrobials used in conventional therapies suggest the need for multi-targeted or combinational therapies aimed at the eradication of biofilms. Antimicrobial tolerance is due to different mechanisms such as the presence of an extracellular matrix that does not allow or slow the penetration of drugs as well as the presence of a metabolic dormancy adopted by many cells inside a biofilm. Furthermore, polymicrobial biofilms represent an additional problem that makes necessary the use of antimicrobials that are efficacious versus all pathogens in biofilms restricting the success of species-specific biofilm-targeting strategies. New antimicrobials and anti-biofilm agents can be of synthetic or natural origin (the biological activity of natural extracts without a proper chemical characteriztion will not be considered).

The proposed Special Issue is a collection of articles focused on biofilm removal strategies/compounds as well as biofilm formation inhibition aimed at (a) the control of biofilm infections and (b) the eradication of a preformed biofilm and/or biofilm monitoring in medicine, food, industry, and natural environments. Our aim is to collect and disseminate some of the most significant and recent contributions in the interdisciplinary areas of microbiology, medicinal chemistry, and pharmacology, with particular emphasis on the feasibility of clinical applications of these strategies. Submissions of original research articles, short communications, review articles, opinion articles, hypotheses, and theory articles are encouraged.

Prof. Dr. Simone Carradori
Dr. Rossella Grande
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

Biofilm
Drug tolerance
Nanosystems
Biomaterials
Anti-biofilm activity
Natural compounds
Antimicrobial peptides
Anti-quorum sensing molecules
New antimicrobials
Bioactive agents
Drug delivery
Surfactants
Synthetic inhibitors
Food contamination
Medical device contamination

Benefits of Publishing in a Special Issue

Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
e-Book format: Special Issues with more than 10 articles can be published as dedicated e-books, ensuring wide and rapid dissemination.

Further information on MDPI's Special Issue polices can be found here.

Published Papers (14 papers)

Download All Papers

Order results

Result details

Show export options Show export options

Select all

Export citation of selected articles as:

Editorial

Jump to: Research, Review

3 pages, 190 KiB

Open AccessEditorial

Novel Biologically Active Molecules, Biomaterials, and Nanoparticles for Microbial Biofilm Control in Human Medicine

by Rossella Grande and Simone Carradori

Molecules 2021, 26(9), 2749; https://doi.org/10.3390/molecules26092749 - 7 May 2021

Cited by 2 | Viewed by 1680

Abstract

The aim of the present special issue, proposed by two Co-Guest Editors with expertise in Clinical Microbiology and Medicinal Chemistry, is to collect and disseminate some of the most significant and innovative contributions focused on biofilm removal strategies, based on the use of natural or synthetic compounds/molecules/peptides or nanoparticles as well as biofilm formation inhibition aimed at both the control and monitoring of biofilm infections in medicine, food, industry, and natural environments [...] Full article

(This article belongs to the Special Issue Novel Biologically Active Molecules, Biomaterials and Nanoparticles for the Microbial Biofilm Control in Human Medicine)

Research

Jump to: Editorial, Review

19 pages, 1788 KiB

Open AccessFeature PaperArticle

Synthesis and Evaluation of Thymol-Based Synthetic Derivatives as Dual-Action Inhibitors against Different Strains of H. pylori and AGS Cell Line

by Francesca Sisto, Simone Carradori, Paolo Guglielmi, Mattia Spano, Daniela Secci, Arianna Granese, Anatoly P. Sobolev, Rossella Grande, Cristina Campestre, Maria Carmela Di Marcantonio and Gabriella Mincione

Molecules 2021, 26(7), 1829; https://doi.org/10.3390/molecules26071829 - 24 Mar 2021

Cited by 14 | Viewed by 3292

Abstract

Following a similar approach on carvacrol-based derivatives, we investigated the synthesis and the microbiological screening against eight strains of H. pylori, and the cytotoxic activity against human gastric adenocarcinoma (AGS) cells of a new series of ether compounds based on the structure of thymol. Structural analysis comprehended elemental analysis and ¹H/¹³C/¹⁹F NMR spectra. The analysis of structure–activity relationships within this molecular library of 38 structurally-related compounds reported that some chemical modifications of the OH group of thymol led to broad-spectrum growth inhibition on all isolates. Preferred substitutions were benzyl groups compared to alkyl chains, and the specific presence of functional groups at para position of the benzyl moiety such as 4-CN and 4-Ph endowed the most anti-H. pylori activity toward all the strains with minimum inhibitory concentration (MIC) values up to 4 µg/mL. Poly-substitution on the benzyl ring was not essential. Moreover, several compounds characterized by the lowest minimum inhibitory concentration/minimum bactericidal concentration (MIC/MBC) values against H. pylori were also tested in order to verify a cytotoxic effect against AGS cells with respect to 5-fluorouracil and carvacrol. Three derivatives can be considered as new lead compounds alternative to current therapy to manage H. pylori infection, preventing the occurrence of severe gastric diseases. The present work confirms the possibility to use natural compounds as templates for the medicinal semi-synthesis. Full article

(This article belongs to the Special Issue Novel Biologically Active Molecules, Biomaterials and Nanoparticles for the Microbial Biofilm Control in Human Medicine)

► Show Figures

Figure 1

21 pages, 2265 KiB

Open AccessArticle

Phytochemical Profiling, In Vitro and In Silico Anti-Microbial and Anti-Cancer Activity Evaluations and Staph GyraseB and h-TOP-IIβ Receptor-Docking Studies of Major Constituents of Zygophyllum coccineum L. Aqueous-Ethanolic Extract and Its Subsequent Fractions: An Approach to Validate Traditional Phytomedicinal Knowledge

by Hamdoon A. Mohammed, Riaz A. Khan, Atef A. Abdel-Hafez, Marwa Abdel-Aziz, Eman Ahmed, Shymaa Enany, Sebaey Mahgoub, Osamah Al-Rugaie, Mansour Alsharidah, Mohamed S. A. Aly, Ahmed B. M. Mehany and Mostafa M. Hegazy

Molecules 2021, 26(3), 577; https://doi.org/10.3390/molecules26030577 - 22 Jan 2021

Cited by 51 | Viewed by 5930

Abstract

Zygophyllum coccineum, an edible halophytic plant, is part of the traditional medicine chest in the Mediterranean region for symptomatic relief of diabetes, hypertension, wound healing, burns, infections, and rheumatoid arthritis pain. The current study aimed to characterize Z. coccineum phytoconstituents, and the evaluations of the anti-microbial-biofilm, and anti-cancers bioactivities of the plant’s mother liquor, i.e., aqueous-ethanolic extract, and its subsequent fractions. The in silico receptors interaction feasibility of Z. coccineum major constituents with Staph GyraseB, and human topoisomerase-IIβ (h-TOP-IIβ) were conducted to confirm the plant’s anti-microbial and anti-cancer biological activities. Thirty-eight secondary metabolites of flavonoids, stilbene, phenolic acids, alkaloids, and coumarin classes identified by LC-ESI-TOF-MS spectrometric analysis, and tiliroside (kaempferol-3-O-(6′′′′-p-coumaroyl)-glucoside, 19.8%), zygophyloside-F (12.78%), zygophyloside-G (9.67%), and isorhamnetin-3-O-glucoside (4.75%) were identified as the major constituents. A superior biofilm obliteration activity established the minimum biofilm eradication concentration (MBEC) for the chloroform fraction at 3.9–15.63 µg/mL, as compared to the positive controls (15.63–31.25 µg/mL) against all the microbial strains that produced the biofilm under study, except the Aspergillus fumigatus. The aqueous-ethanolic extract showed cytotoxic effects with IC₅₀ values at 3.47, 3.19, and 2.27 µg/mL against MCF-7, HCT-116, and HepG2 cell-lines, respectively, together with the inhibition of h-TOP-IIβ with IC₅₀ value at 45.05 ng/mL in comparison to its standard referral inhibitor (staurosporine, IC₅₀, 135.33 ng/mL). This conclusively established the anti-cancer activity of the aqueous-ethanolic extract that also validated by in silico receptor-binding predicted energy levels and receptor-site docking feasibility of the major constituents of the plant’s extract. The study helped to authenticate some of the traditional phytomedicinal properties of the anti-infectious nature of the plant. Full article

(This article belongs to the Special Issue Novel Biologically Active Molecules, Biomaterials and Nanoparticles for the Microbial Biofilm Control in Human Medicine)

► Show Figures

Figure 1

16 pages, 4552 KiB

Open AccessArticle

Ellagic Acid–Cyclodextrin Complexes for the Treatment of Oral Candidiasis

by Aline da Graça Sampaio, Aline Vidal Lacerda Gontijo, Gabriela de Morais Gouvêa Lima, Maria Alcionéia Carvalho de Oliveira, Laura Soares Souto Lepesqueur and Cristiane Yumi Koga-Ito

Molecules 2021, 26(2), 505; https://doi.org/10.3390/molecules26020505 - 19 Jan 2021

Cited by 15 | Viewed by 3082

Abstract

The increase in the prevalence of fungal infections worldwide and the rise in the occurrence of antifungal resistance suggest that new research to discover antifungal molecules is needed. The aim of this study was to evaluate the potential use of ellagic acid–cyclodextrin complexes (EA/HP-β-CD) for the treatment of oral candidiasis. First, the effect of EA/HP-β-CD on C. albicans planktonic cells and biofilms was evaluated. Then, the cytotoxicity of the effective concentration was studied to ensure safety of in vivo testing. Finally, the in vivo effectiveness was determined by using a murine model of induced oral candidiasis. Data was statistically analyzed. The minimal inhibitory concentration of EA/HP-β-CD was 25 µg/mL and a concentration of 10 times MIC (250 µg/mL) showed an inhibitory effect on C. albicans 48 h-biofilms. The complex at concentration 250 µg/mL was classified as slightly cytotoxic. In vivo experiments showed a reduction in fungal epithelial invasion after treatment with EA/HP-β-CD for 24 h and 96 h when compared to the negative control. In conclusion, the results demonstrated that EA/HP-β-CD has antifungal and anti-inflammatory effects, reducing the invasive capacity of C. albicans, which suggests that EA/HP-β-CD may be a promising alternative for the treatment of oral candidiasis. Full article

(This article belongs to the Special Issue Novel Biologically Active Molecules, Biomaterials and Nanoparticles for the Microbial Biofilm Control in Human Medicine)

► Show Figures

Figure 1

20 pages, 2575 KiB

Open AccessArticle

Docking Prediction, Antifungal Activity, Anti-Biofilm Effects on Candida spp., and Toxicity against Human Cells of Cinnamaldehyde

by Danielle da Nóbrega Alves, Alex France Messias Monteiro, Patrícia Néris Andrade, Josy Goldoni Lazarini, Gisely Maria Freire Abílio, Felipe Queiroga Sarmento Guerra, Marcus Tullius Scotti, Luciana Scotti, Pedro Luiz Rosalen and Ricardo Dias de Castro

Molecules 2020, 25(24), 5969; https://doi.org/10.3390/molecules25245969 - 16 Dec 2020

Cited by 41 | Viewed by 4796

Abstract

Objective: This study evaluated the antifungal activity of cinnamaldehyde on Candida spp. In vitro and in situ assays were carried out to test cinnamaldehyde for its anti-Candida effects, antibiofilm activity, effects on fungal micromorphology, antioxidant activity, and toxicity on keratinocytes and human erythrocytes. Statistical analysis was performed considering α = 5%. Results: The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of cinnamaldehyde ranged from 18.91 μM to 37.83 μM. MIC values did not change in the presence of 0.8 M sorbitol, whereas an 8-fold increase was observed in the presence of ergosterol, suggesting that cinnamaldehyde may act on the cell membrane, which was subsequently confirmed by docking analysis. The action of cinnamaldehyde likely includes binding to enzymes involved in the formation of the cytoplasmic membrane in yeast cells. Cinnamaldehyde-treated microcultures showed impaired cellular development, with an expression of rare pseudo-hyphae and absence of chlamydoconidia. Cinnamaldehyde reduced biofilm adherence by 64.52% to 33.75% (p < 0.0001) at low concentrations (378.3–151.3 µM). Cinnamaldehyde did not show antioxidant properties. Conclusions: Cinnamaldehyde showed fungicidal activity through a mechanism of action likely related to ergosterol complexation; it was non-cytotoxic to keratinocytes and human erythrocytes and showed no antioxidant activity. Full article

(This article belongs to the Special Issue Novel Biologically Active Molecules, Biomaterials and Nanoparticles for the Microbial Biofilm Control in Human Medicine)

► Show Figures

Graphical abstract

16 pages, 2610 KiB

Open AccessArticle

Design of Nanosystems for the Delivery of Quorum Sensing Inhibitors: A Preliminary Study

by Supandeep Singh Hallan, Paolo Marchetti, Daria Bortolotti, Maddalena Sguizzato, Elisabetta Esposito, Paolo Mariani, Claudio Trapella, Roberta Rizzo and Rita Cortesi

Molecules 2020, 25(23), 5655; https://doi.org/10.3390/molecules25235655 - 30 Nov 2020

Cited by 18 | Viewed by 2859

Abstract

Biofilm production is regulated by the Quorum Sensing system. Nowadays, Quorum Sensing represents an appealing target to design new compounds to increase antibiotics effects and avoid development of antibiotics multiresistance. In this research the use of liposomes to target two novel synthetic biofilm inhibitors is presented, focusing on a preformulation study to select a liposome composition for in vitro test. Five different liposome (LP) formulations, composed of phosphatidyl choline, cholesterol and charged surfactant (2:1:1, molar ratio) have been prepared by direct hydration and extrusion. As charged surfactants dicetyl phosphate didecyldimethylammonium chloride, di isobutyl phenoxy ethyl dimethyl benzyl ammonium chloride and stearylamine (SA) and have been used. Liposome charge, size and morphology were investigated by zeta potential, photon correlation spectroscopy, small angle x-ray spectroscopy and electron microscopy. LP-SA was selected for the loading of biofilm inhibitors and subjected to high performance liquid chromatography for entrapment capacity evaluation. LP-SA loaded inhibitors showed a higher diameter (223.6 nm) as compared to unloaded ones (205.7 nm) and a dose-dependent anti-biofilm effect mainly after 48 h of treatment, while free biofilm inhibitors loose activity. In conclusion, our data supported the use of liposomes as a strategy to enhance biofilm inhibitors effect. Full article

(This article belongs to the Special Issue Novel Biologically Active Molecules, Biomaterials and Nanoparticles for the Microbial Biofilm Control in Human Medicine)

► Show Figures

Figure 1

14 pages, 2756 KiB

Open AccessArticle

Optimization of Fungal Dextranase Production and Its Antibiofilm Activity, Encapsulation and Stability in Toothpaste

by Nucharee Juntarachot, Duangporn Kantachote, Sartjin Peerajan, Sasithorn Sirilun and Chaiyavat Chaiyasut

Molecules 2020, 25(20), 4784; https://doi.org/10.3390/molecules25204784 - 18 Oct 2020

Cited by 18 | Viewed by 2819

Abstract

Dextranase catalyzes the degradation of the substrate dextran, which is a component of plaque biofilm. This enzyme is involved in antiplaque accumulation, which can prevent dental caries. The activity of crude dextranase from Penicillium roquefortii TISTR 3511 was assessed, and the maximum value (7.61 unit/g) was obtained at 37 °C and pH 6. The Plackett–Burman design was used to obtain significant factors for enhancing fungal dextranase production, and three influencing factors were found: Dextran, yeast extract concentration and inoculum age. Subsequently, the significant factors were optimized with the Box–Behnken design, and the most suitable condition for dextranase activity at 30.24 unit/g was achieved with 80 g/L dextran, 30 g/L yeast extract and five day- old inoculum. The use of 0.85% alginate beads for encapsulation exhibited maximum dextranase activity at 25.18 unit/g beads, and this activity was stable in toothpaste for three months of testing. This study explored the potential production of fungal dextranase under optimal conditions and its encapsulation using alginate for the possibility of applying encapsulated dextranase as an additive in toothpaste products for preventing dental caries. Full article

(This article belongs to the Special Issue Novel Biologically Active Molecules, Biomaterials and Nanoparticles for the Microbial Biofilm Control in Human Medicine)

► Show Figures

Figure 1

12 pages, 2789 KiB

Open AccessArticle

IgY Targeting Bacterial Quorum-Sensing Molecules in Implant-Associated Infections

by Ulrike Dapunt, Birgit Prior, Christopher Oelkrug and Jan Philippe Kretzer

Molecules 2020, 25(17), 4027; https://doi.org/10.3390/molecules25174027 - 3 Sep 2020

Cited by 7 | Viewed by 3220

Abstract

Background: Implant-associated infections are still a major complication in the field of orthopedics. Bacteria can form biofilms on implant surfaces, making them more difficult to detect and treat. Since standard antibiotic therapy is often impaired in biofilm infections, particular interest is directed towards finding treatment alternatives. Biofilm-formation is a well-organized process during which bacteria communicate via quorum-sensing molecules (QSM). The aim of this study was to inhibit bacterial communication by directing avian IgY against specific QSM. Methods: Chicken were immunized against the following QSM: (1) AtlE, a member of the autolysin family which mediates attachment to a surface in Staphylococcus epidermidis; (2) GroEL, the bacterial heat shock protein; (3) PIA (polysaccharide intercellular adhesion), which is essential for cell–cell adhesion in biofilms. Staphylococcus epidermidis biofilms were grown and inhibition of biofilm-formation by IgYs was evaluated. Additionally, human osteoblasts were cultivated and biocompatibility of IgYs was tested. Results: We were able to demonstrate that all IgYs reduced biofilm-formation, also without prior immunization. Therefore, the response was probably not specific with regard to the QSM. Osteoblasts were activated by all IgYs which was demonstrated by microscopy and an increased release of IL-8. Conclusions: In conclusion, avian IgY inhibits biofilm-formation, though the underlying mechanism is not yet clear. However, adverse effects on local tissue cells (osteoblasts) were also observed. Full article

(This article belongs to the Special Issue Novel Biologically Active Molecules, Biomaterials and Nanoparticles for the Microbial Biofilm Control in Human Medicine)

► Show Figures

Figure 1

16 pages, 1956 KiB

Open AccessArticle

Activity of Antimicrobial Peptides and Ciprofloxacin against Pseudomonas aeruginosa Biofilms

by Muhammad Yasir, Debarun Dutta and Mark D.P. Willcox

Molecules 2020, 25(17), 3843; https://doi.org/10.3390/molecules25173843 - 24 Aug 2020

Cited by 29 | Viewed by 6594

Abstract

Pseudomonas aeruginosa is increasingly resistant to conventional antibiotics, which can be compounded by the formation of biofilms on surfaces conferring additional resistance. P. aeruginosa was grown in sub-inhibitory concentrations of the antimicrobial peptides (AMPs) melimine and Mel4 or ciprofloxacin for 30 consecutive days to induce the development of resistance. Antibiofilm effect of AMPs and ciprofloxacin was evaluated using crystal violet and live/dead staining with confocal microscopy. Effect on the cell membrane of biofilm cells was evaluated using DiSC(3)-5 dye and release of intracellular ATP and DNA/RNA. The minimum inhibitory concentration (MIC) of ciprofloxacin increased 64-fold after 30 passages, but did not increase for melimine or Mel4. Ciprofloxacin could not inhibit biofilm formation of resistant cells at 4× MIC, but both AMPs reduced biofilms by >75% at 1× MIC. At 1× MIC, only the combination of either AMP with ciprofloxacin was able to significantly disrupt pre-formed biofilms (≥61%; p < 0.001). Only AMPs depolarized the cell membranes of biofilm cells at 1× MIC. At 1× MIC either AMP with ciprofloxacin released a significant amount of ATP (p < 0.04), but did not release DNA/RNA. AMPs do not easily induce resistance in P. aeruginosa and can be used in combination with ciprofloxacin to treat biofilm. Full article

(This article belongs to the Special Issue Novel Biologically Active Molecules, Biomaterials and Nanoparticles for the Microbial Biofilm Control in Human Medicine)

► Show Figures

Figure 1

12 pages, 2585 KiB

Open AccessArticle

Increased Antibacterial and Antibiofilm Properties of Silver Nanoparticles Using Silver Fluoride as Precursor

by Federico Bertoglio, Lorenzo De Vita, Agnese D’Agostino, Yuri Diaz Fernandez, Andrea Falqui, Alberto Casu, Daniele Merli, Chiara Milanese, Silvia Rossi, Angelo Taglietti, Livia Visai and Piersandro Pallavicini

Molecules 2020, 25(15), 3494; https://doi.org/10.3390/molecules25153494 - 31 Jul 2020

Cited by 16 | Viewed by 3176

Abstract

Silver nanoparticles were produced with AgF as the starting Ag(I) salt, with pectin as the reductant and protecting agent. While the obtained nanoparticles (pAgNP-F) have the same dimensional and physicochemical properties as those already described by us and obtained from AgNO₃ and pectin (pAgNP-N), the silver nanoparticles from AgF display an increased antibacterial activity against E. coli PHL628 and Staphylococcus epidermidis RP62A (S. epidermidis RP62A), both as planktonic strains and as their biofilms with respect to pAgNP-N. In particular, a comparison of the antimicrobial and antibiofilm action of pAgNP-F has been carried out with pAgNP-N, pAgNP-N and added NaF, pure AgNO₃, pure AgF, AgNO₃ and added NaF and pure NaNO₃ and NaF salts. By also measuring the concentration of the Ag⁺ cation released by pAgNP-F and pAgNP-N, we were able to unravel the separate contributions of each potential antibacterial agent, observing an evident synergy between p-AgNP and the F⁻ anion: the F⁻ anion increases the antibacterial power of the p-AgNP solutions even when F⁻ is just 10 µM, a concentration at which F⁻ alone (i.e., as its Na⁺ salt) is completely ineffective. Full article

(This article belongs to the Special Issue Novel Biologically Active Molecules, Biomaterials and Nanoparticles for the Microbial Biofilm Control in Human Medicine)

► Show Figures

Figure 1

11 pages, 2114 KiB

Open AccessArticle

Metabolic Current Production by an Oral Biofilm Pathogen Corynebacterium matruchotii

by Divya Naradasu, Waheed Miran and Akihiro Okamoto

Molecules 2020, 25(14), 3141; https://doi.org/10.3390/molecules25143141 - 9 Jul 2020

Cited by 14 | Viewed by 3453

Abstract

The development of a simple and direct assay for quantifying microbial metabolic activity is important for identifying antibiotic drugs. Current production capabilities of environmental bacteria via the process called extracellular electron transport (EET) from the cell interior to the exterior is well investigated in mineral-reducing bacteria and have been used for various energy and environmental applications. Recently, the capability of human pathogens for producing current has been identified in different human niches, which was suggested to be applicable for drug assessment, because the current production of a few strains correlated with metabolic activity. Herein, we report another strain, a highly abundant pathogen in human oral polymicrobial biofilm, Corynebacterium matruchotii, to have the current production capability associated with its metabolic activity. It showed the current production of 50 nA/cm² at OD₆₀₀ of 0.1 with the working electrode poised at +0.4 V vs. a standard hydrogen electrode in a three-electrode system. The addition of antibiotics that suppress the microbial metabolic activity showed a significant current decrease (>90%), establishing that current production reflected the cellular activity in this pathogen. Further, the metabolic fixation of atomically labeled ¹³C (31.68% ± 2.26%) and ¹⁵N (19.69% ± 1.41%) confirmed by high-resolution mass spectrometry indicated that C. matruchotii cells were metabolically active on the electrode surface. The identified electrochemical activity of C. matruchotii shows that this can be a simple and effective test for evaluating the impact of antibacterial compounds, and such a method might be applicable to the polymicrobial oral biofilm on electrode surfaces, given four other oral pathogens have already been shown the current production capability. Full article

(This article belongs to the Special Issue Novel Biologically Active Molecules, Biomaterials and Nanoparticles for the Microbial Biofilm Control in Human Medicine)

► Show Figures

Figure 1

12 pages, 1888 KiB

Open AccessArticle

Lipoteichoic Acid Biosynthesis Inhibitors as Potent Inhibitors of S. aureus and E. faecalis Growth and Biofilm Formation

by George A. Naclerio, Kenneth I. Onyedibe and Herman O. Sintim

Molecules 2020, 25(10), 2277; https://doi.org/10.3390/molecules25102277 - 12 May 2020

Cited by 32 | Viewed by 4872

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE) have been deemed as serious threats by the CDC. Many chronic MRSA and VRE infections are due to biofilm formation. Biofilm are considered to be between 10–10,000 times more resistant to antibiotics, and therefore new chemical entities that inhibit and/or eradicate biofilm formation are needed. Teichoic acids, such as lipoteichoic acids (LTAs) and wall teichoic acids (WTAs), play pivotal roles in Gram-positive bacteria’s ability to grow, replicate, and form biofilms, making the inhibition of these teichoic acids a promising approach to fight infections by biofilm forming bacteria. Here, we describe the potent biofilm inhibition activity against MRSA and VRE biofilms by two LTA biosynthesis inhibitors HSGN-94 and HSGN-189 with MBICs as low as 0.0625 µg/mL against MRSA biofilms and 0.5 µg/mL against VRE biofilms. Additionally, both HSGN-94 and HSGN-189 were shown to potently synergize with the WTA inhibitor Tunicamycin in inhibiting MRSA and VRE biofilm formation. Full article

(This article belongs to the Special Issue Novel Biologically Active Molecules, Biomaterials and Nanoparticles for the Microbial Biofilm Control in Human Medicine)

► Show Figures

Graphical abstract

Review

Jump to: Editorial, Research

40 pages, 1734 KiB

Open AccessReview

Approaches for Mitigating Microbial Biofilm-Related Drug Resistance: A Focus on Micro- and Nanotechnologies

by Harinash Rao, Sulin Choo, Sri Raja Rajeswari Mahalingam, Diajeng Sekar Adisuri, Priya Madhavan, Abdah Md. Akim and Pei Pei Chong

Molecules 2021, 26(7), 1870; https://doi.org/10.3390/molecules26071870 - 26 Mar 2021

Cited by 24 | Viewed by 5597

Abstract

Biofilms play an essential role in chronic and healthcare-associated infections and are more resistant to antimicrobials compared to their planktonic counterparts due to their (1) physiological state, (2) cell density, (3) quorum sensing abilities, (4) presence of extracellular matrix, (5) upregulation of drug efflux pumps, (6) point mutation and overexpression of resistance genes, and (7) presence of persister cells. The genes involved and their implications in antimicrobial resistance are well defined for bacterial biofilms but are understudied in fungal biofilms. Potential therapeutics for biofilm mitigation that have been reported include (1) antimicrobial photodynamic therapy, (2) antimicrobial lock therapy, (3) antimicrobial peptides, (4) electrical methods, and (5) antimicrobial coatings. These approaches exhibit promising characteristics for addressing the impending crisis of antimicrobial resistance (AMR). Recently, advances in the micro- and nanotechnology field have propelled the development of novel biomaterials and approaches to combat biofilms either independently, in combination or as antimicrobial delivery systems. In this review, we will summarize the general principles of clinically important microbial biofilm formation with a focus on fungal biofilms. We will delve into the details of some novel micro- and nanotechnology approaches that have been developed to combat biofilms and the possibility of utilizing them in a clinical setting. Full article

(This article belongs to the Special Issue Novel Biologically Active Molecules, Biomaterials and Nanoparticles for the Microbial Biofilm Control in Human Medicine)

► Show Figures

Figure 1

10 pages, 451 KiB

Open AccessReview

Gentamicin-Coated Tibia Nail in Fractures and Nonunion to Reduce Fracture-Related Infections: A Systematic Review

by Daniele De Meo, Federico M. Cannari, Luisa Petriello, Pietro Persiani and Ciro Villani

Molecules 2020, 25(22), 5471; https://doi.org/10.3390/molecules25225471 - 23 Nov 2020

Cited by 23 | Viewed by 3035

Abstract

The incidence of a fracture-related infection (FRI) can reach 30% of open tibia fractures (OTF). The use of antibiotic-coated implants is one of the newest strategies to reduce the risk of infection in orthopedic surgery. The aim of this study was to investigate the efficacy and safety of a gentamicin-coated tibia nail in primary fracture fixation (FF) and revision surgery (RS) of nonunion cases in terms of FRI incidence. We conducted a systematic review according to the PRISMA checklist on Pub-Med, Cochrane, and EMBASE. Of the 32 studies, 8 were included, for a total of 203 patients treated: 114 were FF cases (63% open fractures) and 89 were RS cases, of which 43% were infected nonunion. In the FF group, four FRI were found (3.8%): three OTF (Gustilo-Anderson III) and one closed fracture; bone healing was achieved in 94% of these cases. There were four relapses of infection and one new onset in the RS group; bone healing occurred in 88% of these cases. No side effects were found. There were no significant differences in terms of FRI, nonunion, and healing between the two groups. Gentamicin-coated tibia nail is an effective therapeutic option in the prophylaxis of high-risk fracture infections and in complex nonunion cases. Full article

(This article belongs to the Special Issue Novel Biologically Active Molecules, Biomaterials and Nanoparticles for the Microbial Biofilm Control in Human Medicine)

► Show Figures

Journal Menu

Journal Browser

Novel Biologically Active Molecules, Biomaterials and Nanoparticles for the Microbial Biofilm Control in Human Medicine

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (14 papers)

Editorial

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI