Local Bacterial Infection Research Articles

Burns, Sepsis and Procalcitonin

The basis of the pathogenesis of burn disease is a systemic inflammatory response syndrome with episodes of bacteremia and the development of sepsis. An analysis of the literature showed that the existing clinical diagnostic scales for sepsis do not allow a confident diagnosis. The interest in changes in the concentration of procalcitonin in the blood serum is justified by the fact that this prohormone is one of the proinflammatory mediators, the concentration of which quickly increases during local and systemic bacterial and fungal infections. It seems important to consider the possibilities of various scales for determining the criteria for sepsis, analyze the values of procalcitonin and its monitoring for more effective diagnosis and procalcitonin-controlled antibiotic therapy in patients with burns.CONCLUSION. The problem of clinical diagnosis of sepsis in patients with burns has not yet been solved. Procalcitonin is an effective biomarker of bacterial infection, and its monitoring reflects the dynamics of the burn disease, predicts the outcome, indicates the effectiveness of antibiotic therapy and allows for its correction.

Blood levels of zearalenone, thyroid-stimulating hormone, and thyroid hormones in patients with colorectal cancer

Mycotoxins are secondary metabolites produced by various species of mold fungi commonly found in plant materials. Zearalenone (ZEN) adversely affects the endocrine system. This study aimed to determine whether thyroid-stimulating hormone (TSH), procalcitonin (PCT), free triiodothyronine (fT3), and free thyroxine (fT4) levels are altered during natural zearalenone mycotoxicosis in patients diagnosed with sigmoid colon cancer (SCC) or colorectal cancer (CRC). A study was conducted on women and men diagnosed with SCC or CRC accompanied by the presence or absence (Patients Without ZEN – PWZ group) of ZEN in the blood. The PWZ group consisted of 17 patients with symptoms of SCC and CRC in whom ZEN and its metabolites were not detected in peripheral blood. The experimental (empirical) groups included a total of 16 SCC and CRC patients who tested positive for ZEN, but not its metabolites. TSH values in both sexes were within the upper limit of the reference range (0.27 – 4.2 μIU/mL) adopted by the hospital laboratory and corresponded to the upper second tertile and the lower third tertile. PCT values demonstrated that SCC and CRC were accompanied by a systemic or local bacterial infection. All mean values of fT3 were in the middle of the reference range, and the mean values of fT4 were within the upper reference limit. The fT3/fT4 prognostic marker was somewhat above the cut-off point of 0.22. These results indicate that in postmenopausal women and andropausal men who were diagnosed with SCC and CRC and were exposed to food-borne ZEN, higher values of the prognostic marker (fT3/fT4) were associated with an unfavorable prognosis. The study also revealed that the more distal the neoplastic lesions in the colon, the higher the percentage of both thyroid hormones, regardless of the patient's sex. The presence of ZEN in the diet alters thyroid activity in patients diagnosed with SCC and CRC.

Polymeric Antibiotic Beads for Canine Osteomyelitis: Advancing Localized Antibiotic Treatment with Enhanced Efficacy and Minimized Side Effects

Antibiotic beads represent a compelling treatment method for the treatment and prevention of canine osteomyelitis, as they provide localized antibiotic concentrations at the infection site with minimal systemic toxicity. The therapeutic efficacy of these beads has been demonstrated, highlighting their potential as a valuable local antibiotic therapy. In particular, the introduction of vancomycin - polymethylmethacrylate (PMMA) beads is highlighted as a promising new form of local antibiotic therapy. This article focuses on the use of antibiotic-impregnated beads to treat localized bacterial infections in the bones and joints of canines. Typically composed of poly(lactic-co-glycolic acid) (PLGA) or polymethylmethacrylate (PMMA), these beads contain antibiotics such as vancomycin, placed directly into the affected area, providing a high antibiotic concentration at the site of infection. These beads were developed for a slow antibiotic release over time; they ensure a constant protective effect against a broad spectrum of bacteria, demonstrating high efficacy and biocompatibility with the animal's body. This localized antibiotic treatment option offers several advantages over systemic antibiotics, such as reduced side effects and improved efficacy. It could be a promising option for the treatment of bone and joint infections in canines.

On-demand bactericidal and self-adaptive antifouling hydrogels for self-healing and lubricant coatings of catheters

Catheter-related infections are one of the most common nosocomial infections with increasing morbidity and mortality, and robust antibacterial or antifouling catheter coatings remain great challenges for long-term implantation. Herein, multifunctional hydrogel coatings were developed to provide persistent and self-adaptive antifouling and antibacterial effects with self-healing and lubricant capabilities. Polyvinyl alcohol (PVA) with β-cyclodextrin (β-CD) grafts (PVA-Cd) and 4-arm polyethylene glycol (PEG) with adamantane and quaternary ammonium compound (QAC) terminals (QA-PEG-Ad) were crosslinked through host-guest recognitions between adamantane and β-CD moieties to acquire PVEQ coatings. In response to bacterial infections, QACs exhibit reversible transformation between zwitterions (pH 7.4) and cationic lactones (pH 5.5) to generate on-demand bactericidal effect. Highly hydrophilic PEG/PVA backbones and zwitterionic QACs build a lubricate surface and decrease the friction coefficient 10 times compared with that of bare catheters. The antifouling hydrated layer significantly inhibits blood protein adsorption and platelet activation and reveals negligible hemolysis and cytotoxicity. The dynamic host-guest crosslinking achieves full self-healing of cracks in PVEQ hydrogels, and the mechanical profiles were recovered to over 90 % after rejuvenating the broken hydrogels, exhibiting a long-term stability after mechanical stretching, twisting, knotting and compression. After subcutaneous implantation and local bacterial infection, the retrieved PVEQ-coated catheters display no tissue adhesion and 3 log folds lower bacterial number than that of bare catheters. PVEQ coatings effectively prevent the repeated bacterial infections and there are few inflammatory reactions in the surrounding tissue, while substantial lymphoid infiltration and inflammatory cell aggregation occur in muscle tissues around the bare catheter. Thus, this study demonstrates a catheter coating strategy by on-demand bactericidal, self-adaptive antifouling, self-healing and lubricant hydrogels to address medical devices-related infections. Statement of significanceIt is estimated over two billion peripheral intravenous catheters are annually used in hospitals around the world, and catheter-associated infection has become a great clinical challenge with rapidly rising morbidity and mortality. Surface coating is considered a promising approach, but substantial challenges remain in the development of coatings that simultaneously satisfy both anti-fouling and antibacterial attributes. Even more, few attempts have been made to design mechanically robust coatings and reversible antibacterial or antifouling capabilities, which are critical for long-term medical implants. To address these challenges, we propose a concise strategy to develop hydrogel coatings from commercially available poly(ethylene glycol) and polyvinyl alcohol. In addition to self-healing and lubricant capabilities, the reversible conversion between zwitterionic and cationic lactones of quaternary ammonium compounds enables on-demand bactericidal and self-adaptive antifouling effects.

Immunosuppressive Induction Therapy Using the Antithymocyteglobulin Grafalon: A Single-Center Non-Interventional Study.

Background: Induction therapy with depleting antibodies in the setting of liver transplantation (LT) is discussed controversially to this day. The rabbit antithymocyteglobulin (ATG) Thymoglobulin (rATG) was introduced as early as 1984 and was frequently used as a standard regime for induction therapy after LT. There are no public reports characterizing Grafalon (ATG-F), a novel ATG, as an induction agent after LT. Objectives: The aim of this observational non-interventional study was to investigate the safety and efficacy of Grafalon induction therapy and characterize its clinical effects in the setting of LT. Methods: A cohort of 80 patients undergoing deceased donor LT at the Medical University of Vienna and receiving Grafalon as part of the clinical standard immunosuppressive regimen was prospectively included between March 2021 and November 2022. Patients were monitored closely for leukocytopenia and thrombocytopenia during the first postoperative week and followed up for incidence and severity of biopsy-proven acute rejection (BPAR), overall survival, and bacterial infections in the first year after LT. Results: The incidences of thrombocytopenia and leukocytopenia following Grafalon treatment peaked on postoperative day four, with 64% and 31%, respectively. However, there were no cases of severe leukocytopenia after the first postoperative week. Induction therapy with Grafalon resulted in a rate of localized bacterial infections and bacteremia of 28% and 21%, respectively. The rate of BPAR was 12.5% in the first year after LT; the one-year survival rate in this cohort was 90%. Conclusions: Overall, this study provides evidence of the safety and efficacy of Grafalon as an induction agent. Further studies investigating the potential long-term effects of Grafalon, as well as comparison studies with different immunosuppressive regimens, are needed in order to draw further conclusions.

Optimizing alkaline hydrothermal treatment for biomimetic smart metallic orthopedic and dental implants

Orthopedic and dental implant failure continues to be a significant concern due to localized bacterial infections. Previous studies have attempted to improve implant surfaces by modifying their texture and roughness or coating them with antibiotics to enhance antibacterial properties for implant longevity. However, these approaches have demonstrated limited effectiveness. In this study, we attempted to engineer the titanium (Ti) alloy surface biomimetically at the nanometer scale, inspired by the cicada wing nanostructure using alkaline hydrothermal treatment (AHT) to simultaneously confer antibacterial properties and support the adhesion and proliferation of mammalian cells. The two modified Ti surfaces were developed using a 4 h and 8 h AHT process in 1 N NaOH at 230 °C, followed by a 2-hour post-calcination at 600 °C. We found that the control plates showed a relatively smooth surface, while the treatment groups (4 h & 8 h AHT) displayed nanoflower structures containing randomly distributed nano-spikes. The results demonstrated a statistically significant decrease in the contact angle of the treatment groups, which increased wettability characteristics. The 8 h AHT group exhibited the highest wettability and significant increase in roughness 0.72 ± 0.08 µm (P < 0.05), leading to more osteoblast cell attachment, reduced cytotoxicity effects, and enhanced relative survivability. The alkaline phosphatase activity measured in all different groups indicated that the 8 h AHT group exhibited the highest activity, suggesting that the surface roughness and wettability of the treatment groups may have facilitated cell adhesion and attachment and subsequently increased secretion of extracellular matrix. Overall, the findings indicate that biomimetic nanotextured surfaces created by the AHT process have the potential to be translated as implant coatings to enhance bone regeneration and implant integration.Graphical

Borate bonds-containing pH-responsive chitosan hydrogel for postoperative tumor recurrence and wound infection prevention

Chitosan has been widely used in biomedical fields due to its good antibacterial properties, excellent biocompatibility, and biodegradability. In this study, a pH-responsive and self-healing hydrogel was synthesized from 3-carboxyphenylboronic acid grafted with chitosan (CS-BA) and polyvinyl alcohol (PVA). The dynamic boronic ester bonds and intermolecular hydrogen bonds are responsible for the hydrogel formation. By changing the mass ratio of CS-BA and PVA, the tensile stress and compressive stress of hydrogel can controlled in the range of 0.61 kPa - 0.74 kPa and 295.28 kPa - 1108.1 kPa, respectively. After doping with tannic acid (TA)/iron nanocomplex (TAFe), the hydrogel successful killed tumor cells through the near infrared laser-induced photothermal conversion and the TAFe-triggered reactive oxygen species generation. Moreover, the photothermal conversion of the hydrogel and the antibacterial effect of CS and TA give the hydrogel a good antibacterial effect. The CS-BA/PVA/TAFe hydrogel exhibit good in vivo and in vitro anti-tumor recurrence and antibacterial ability, and therefore has the potential to be used as a powerful tool for the prevention of local tumor recurrence and bacterial infection after surgery.

Effect of carbon quantum dots doping on structural, optical, and antibacterial properties of barium tungstate nanocomposite material

Local bacterial infection remains an increasingly severe threat to human health worldwide, and infection control is still a challenging task. Carbon Quantum Dots (CQSs) and barium tungstate show antibacterial properties. CQDs doped Barium Tungstate (BaWO4) are synthesized by using a hydrothermal route and their optical and antimicrobial activities against the Gram-positive bacteria staphylococcus aureus and optical properties were investigated. The UV–Vis reveals a shift in the bandgap from 3.62 eV to 2.93 eV due to doping of CQDs in BaWO4. The structure of the CQDs/BaWO4 were studied by XRD, which shows CQDs doped BaWO4 samples possess tetragona4 werelite structure with the preferred orientation of (112) identified by XRD at 26° having crystallite size ∼ 31 nm. Nanocomposite BaWO4/CQDs exhibit a spherical-like shape and are composed of Ba, O, W and C according to the design of the experiment. Zeta sizer of CQDs by DLS shows the size of CQDs is 7.65 nm. The FT-IR shows the presence of functional groups in doped material like CC, CO, and COOH bonds which indicate that the C-dots are functionalized with epoxy, carbonyl, hydroxyl, and carboxylic acid groups. Their elemental composition and surface morphology were studied by EDS which shows the percentage variation of CQDs in BaWO4, SEM results show the change in shape of the sample by adding CQDs to BaWO4. The TEM image proves the presence of doped material in the BaWO4. The PL spectra reveals the emission spectra shift towards a higher wavelength and absorption increases. The qualitative analysis shows the antimicrobial activity and enlargement of the inhibition zone and quantitative analysis confirms it.

Plant-based compositions for the treatment of local and topical bacterial infections: a patent review.

Aim: To examine recent patents related to plants with antimicrobial effects. Methods: Ourinvestigation was carried out using theEspacenet database, searching patents related to International Patent Classification (IPC) codes A61P31/04, and A61K36/00 between2008and2023. Results: The study began with 360 patents, of which 15 were found to be duplicates; 144 were not related to the research topicand six were not available. Then, 48 patentswere related to other administration routes. The final selection was 47 patents related to local administration compositions. The potential for these herbal compositions to be marketed as over-the-counter medicines was evident. Conclusion: Developing new plant-origin anti-infective agents could provide promising solutions for combating resistant infections and offer accessible treatment options.

Multifunctional carbon quantum dots decorated self-healing hydrogel for highly effective treatment of superbug infected wounds

Rapid healing of wounds infected by bacteria, especially multidrug-resistant bacteria, is a common clinical challenge. Local bacterial infection causes excessive reactive oxygen species (ROS) that further induce oxidative stress and inflammatory responses, which impairs cell migration, angiogenesis and delays cutaneous regeneration. Herein, we designed a novel type of carbon quantum dots (CQDs) derived from herbal medicines. The CQDs are able to against gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA), and possessed SOD-like as well as CAT-like activities for scavenging ROS. The biocompatible CQDs could protect HUVECs migration and angiogenesis from oxidative stress damage. Moreover, the expression of NO and pro-inflammatory cytokines (TNF-α and IL-6) of LPS-induced macrophages could be downregulated by the CQDs. Besides, the self-healing hydrogel decorated with multifunctional CQDs were prepared via the reaction between OSA and CMCS through Schiff base linkage for better wound management. The CQDs/hydrogel could continuously eliminate bacteria and scavenge ROS to modulate the complex oxidative stress microenvironment. The results of animal experiments demonstrated that the CQDs/hydrogel exerted the effects of eliminating MRSA, anti-inflammation, and promoting angiogenesis, which was manifested in enhancing wound healing, epithelial regeneration and collagen disposition. Therefore, the CQDs/hydrogel is excellent candidate for MRSA-infected skin wound healing.

Conjugated Polymer Composite Nanoparticles Augmenting Photosynthesis-Based Light-Triggered Hydrogel Promotes Chronic Wound Healing.

Diabetic chronic wounds are characterized by local hypoxia, impaired angiogenesis, and bacterial infection. In situ, self-supply of dissolved oxygen combined with the elimination of bacteria is urgent and challenging for chronic nonhealing wound treatment. Herein, an oxygen-generating system named HA-L-NB/PFE@cp involving biological photosynthetic chloroplasts (cp)/conjugated polymer composite nanoparticles (PFE-1-NPs@cp) and light-triggered hyaluronic acid-based (HA-L-NB) hydrogel for promoting diabetic wound healing is introduced. Briefly, conjugated polymer nanoparticles (PFE-1-NPs) possess unique light harvesting ability, which accelerates the electron transport rates in photosystem II (PS II) by energy transfer, elevating photosynthesis beyond natural chloroplasts. The enhanced release of oxygen can greatly relieve hypoxia, promote cell migration, and favor antibacterial photodynamic therapy. Additionally, the injectable hydrogel precursors are employed as a carrier to deliver PFE-1-NPs@cp into the wound. Under light irradiation, they quickly form a gel by S-nitrosylation coupling reaction and in situ anchor on tissues through amine-aldehyde condensation. Both in vitro and in vivo assays demonstrate that the oxygen-generating system can simultaneously relieve wound hypoxia, eliminate bacteria, and promote cell migration, leading to the acceleration of wound healing. This study provides a facile approach to develop an enhanced oxygen self-sufficient system for promoting hypoxic tissue, especially diabetic wound healing.

PCT, IL-6, and IL-10 facilitate early diagnosis and pathogen classifications in bloodstream infection

BackgroundIn the diagnosis of bloodstream infection (BSI), various inflammatory markers such as C-reactive protein (CRP), procalcitonin (PCT), interleukins (IL), white blood cell count (WBC), neutrophil percentage (NE%), platelet count (PLT), and erythrocyte sedimentation rate (ESR) have been extensively utilized. However, their specific roles in distinguishing BSI from local bacterial infection (LBI) and in classifying BSI pathogens remain uncertain.MethodsA historical cohort study was conducted, involving the enrollment of 505 patients with BSI and 102 patients with LBI. To validate the reliability of the clinical data obtained from this cohort, mouse models of BSI were utilized.ResultsOur findings revealed that patients with BSI had significantly higher levels of inflammatory markers, including CRP, PCT, IL-6, IL-10, WBC, NE%, and ESR, compared to those with LBI (p < 0.05). The receiver operating characteristic (ROC) curve analysis demonstrated that CRP, PCT, IL-6, IL-10, ESR and NE% exhibited excellent diagnostic efficacy for BSI. Additionally, we observed significant differences in CRP, PCT, IL-6, and IL-10 levels between patients with BSI caused by Gram-positive bacteria (GP-BSI) and Gram-negative bacteria (GN-BSI), but no significant variations were found among specific bacterial species. Furthermore, our study also found that CRP, PCT, and IL-10 have good discriminatory ability for vancomycin-resistant Enterococcus (VRE), but they show no significant diagnostic efficacy for other multidrug-resistant organisms (MDROs) such as carbapenem-resistant Enterobacteriaceae (CRE), carbapenem-resistant Pseudomonas aeruginosa (CRPA), and methicillin-resistant Staphylococcus aureus (MRSA). In our mouse model experiments, we observed a remarkable increase in PCT, IL-6, and IL-10 levels in mice with GN-BSI compared to those with GP-BSI.ConclusionOur study has confirmed that PCT, IL-6, and IL-10 are efficient biomarkers for distinguishing between BSI and LBI. Furthermore, they can be utilized to classify BSI pathogens and differentiate between VRE and vancomycin-susceptible Enterococcus. These findings are extremely valuable for clinicians as they enable timely initiation of empiric antibiotic therapies and ultimately lead to improved clinical outcomes for patients with BSI.

Prompt antibacterial activity of silver nanoparticle decorated on HAp embedded NiFe2O4 nanocomposite (NiFe2O4@HAp-Ag) against pathogenic strains and investigation of its photocatalytic activity towards degradation of antibiotics

Local bacterial infection in clinics is still a difficult task and poses serious health threats to human. Systemic antibiotic administration typically results in negative side-effects and bacterial resistance and only has transient antibacterial activity. Several biomedical applications immensely prefer modified hydroxyapatite with excellent biocompatibility and antibacterial characteristics. Herein, we fabricate hydroxyapatite-embedded NiFe2O4 using in situ hydrothermal method and used as a support for silver nanoparticle onto its surface to achieve an effective biological response. The properties of the as-synthesized materials were characterized using several spectroscopic techniques which include X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, ultraviolet–diffuse reflectance spectroscopy spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, high resolution transmission electron microscopy. In addition, the magnetic behavior of these nanocomposites was examined using the vibrating sample magnetometer technique. This ternary nanocomposite exhibits potent antimicrobial activity against both Gram-negative bacteria (Pseudomonas aeruginosa and klebsiella pneumoniae) as well as Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus). The MIC or minimum inhibitory concentration, MBC or minimum bactericidal concentration, the disc diffusion, bacterial growth rate, and inhibition rate tests were utilized for the examination of the antimicrobial effect of this synthesized nanocomposite against pathogenic strains. Along with this, we have also investigated its photocatalytic activity toward degradation of cefixime antibiotic under solar light and it shows excellent photodegradation performance. The fabricated nanocomposite demonstrated high reusability with good photostability. Notably, using magnetic decantation this prepared nanocomposite can be easily eliminated from the disinfected medium.

Smart Wearable Patches Using Light-Controlled Activation and Delivery of Photoswitchable Antimicrobial Peptides.

A novel strategy to treat Staphylococcus aureus (S. aureus) skin infections is presented, where UV light is used to facilitate concomitant light-controlled activation and delivery of an antimicrobial therapeutic agent. Specifically, a new photoswitchable gramicidin S analogue was immobilized onto a polymeric wearable patch via a photocleavable linker that undergoes photolysis at the same wavelength of light required for activation of the peptide. Unlike toxic gramicidin S, the liberated active photoswitchable peptide exhibits antimicrobial activity against S. aureus while being ostensibly non-haemolytic to red blood cells. Moreover, irradiation with visible light switches off the antimicrobial properties of the peptide within seconds, presenting an ideal strategy to regulate antibiotic activity for localized bacterial infections with the potential to mitigate resistance.

Hyaluronic Acid-Alginate Homogeneous Structures with Polylactide Coating Applied in Controlled Antibiotic Release.

The use of a controlled-release drug carrier is an innovative solution for the treatment of local infections, in particular in dentistry, skin diseases, and in open wounds. The biocompatibility, biodegradability, the possibility of a large amount of drug adsorbed (especially those with hydrophilic properties), and the ability to create structures of any shape and size are the reasons for hydrogels to be frequently studied. The main disadvantage of hydrogel carriers is the rapid rate of drug release; hence, in this study, an attempt was made to additionally chemically cross-link 1-ethyl-3-(3-dimethyl aminopropyl)-1-carbodiimide hydrochloride (EDC) with the hyaluronic acid-alginate (HA-SAL) structure. The answer to significantly reduce the mass flux typical for hydrogel structure was to surround it with a polymer layer using a dry cover. By coating the carriers with polylactide, the release time was increased by around forty times. As the carriers were designed to reduce local bacterial infections, among others in dentistry, the released antibiotics were amoxycillin, metronidazole, and doxycycline.

Two Cases of Acute Focal Bacterial Nephritis With Central Nervous System Manifestations in Children and Literature Review.

Acute focal bacterial nephritis (AFBN) is a kidney disease characterized by a localized bacterial infection that manifests as an inflammatory mass. Most children with AFBN have nonspecific symptoms including fever, vomiting, and abdominal discomfort, and some develop neurological symptoms such as meningeal irritation, unconsciousness, and seizures as their condition worsens. This was 2 cases of AFBN with central nervous system manifestations in children, and we analyzed its possible mechanisms of the clinical and radiographic features. We experience 2 very unusual cases of AFBN which were linked to central nervous system abnormalities. A 6-year-old boy with AFBN and clinically moderate ncephalitis/encephalopathy with a reversible splenial lesion (MERS) presented with neurological symptoms, including unconsciousness and convulsions. The second case involved an 8-year-old child with AFBN-associated acute encephalopathy who exhibited neurological symptoms, including unconsciousness. According to previous research, AFBN is linked to central nervous system impairment. As a result, when a clinician meets a patient with an inexplicable fever caused by a neurological condition, he should pay attention to this diagnosis of AFBN and follow it in the abdominal graph.

Nucleopeptide-Coupled Injectable Bioconjugated Guanosine-Quadruplex Hydrogel with Inherent Antibacterial Activity.

The multicomponent reaction-directed self-assembled hydrogels offer the opportunities to fabricate materials with ubiquitous properties which sometimes are not possible to generate from single components. Therefore, multicomponent-derived hydrogels have enormous applications in biomedical fields, and the number of such systems is increasing day by day. Herein, the multicomponent self-assembly techniques have been employed to develop a biomimetic low-molecular-weight G-quadruplex hydrogel under physiological conditions. The bioconjugation of guanosine, 4-formylphenylboronic acid, and cytosine-functionalized nucleopeptide (NP) is important to generate the multicomponent self-assembled dynamic imino-boronate ester-mediated bioconjugated G-quadruplex hydrogels. Using thioflavin T fluorescence assay, powder X-ray diffraction, and circular dichroism spectroscopic techniques, we confirm the existence of a G-quartet-like structure as the key parameter for the formation of nanofibrillar hydrogels. The multicomponent self-assembled G-quadruplex hydrogel possesses excellent inherent antibacterial activity against a broad range of bacterial species. The in vitro cytocompatibility of the synthesized hydrogel was evaluated on MCF-7 and HEK 293T cell lines to study the biocompatibility of the hydrogel. The proposed injectable, biocompatible, and NP-coupled G-quadruplex hydrogel with inherent antibacterial efficiency holds promising importance to prevent localized bacterial infections.

Silver-Nanoparticle-Embedded Short Amphiphilic Peptide Nanostructures and Their Plausible Application to Reduce Bacterial Infections.

The microbiota-gut-brain axis (GBA) plays a critical role in the development of neurodegenerative diseases. Dysbiosis of the intestinal microbiome causes a significant alteration in the gut microbiota of Alzheimer's disease (AD) patients, followed by neuroinflammatory processes. Thus, AD beginning in the gut is closely related to an imbalance in gut microbiota, and hence a multidomain approach to reduce this imbalance by exerting positive effects on the gut microbiota is needed. In one example, a tyrosine-based short peptide amphiphile (sPA) was used to synthesize antibacterial AgNPs-sPA nanostructures. Such nanostructures showed high biocompatibility and low cytotoxicity, and therefore work as model drug delivery agents for addressing local bacterial infections. These may have therapeutic value for the treatment of microbiota-triggered progression of neurodegenerative diseases.

Enrichment of Bone Tissue with Antibacterially Effective Amounts of Nitric Oxide Derivatives by Treatment with Dielectric Barrier Discharge Plasmas Optimized for Nitrogen Oxide Chemistry.

Cold atmospheric plasmas (CAPs) generated by dielectric barrier discharge (DBD), particularly those containing higher amounts of nitric oxide (NO) or NO derivates (NOD), are attracting increasing interest in medical fields. In the present study, we, for the first time, evaluated DBD-CAP-induced NOD accumulation and therapeutically relevant NO release in calcified bone tissue. This knowledge is of great importance for the development of new therapies against bacterial-infectious complications during bone healing, such as osteitis or osteomyelitis. We found that by modulating the power dissipation in the discharge, it is possible (1) to significantly increase the uptake of NODs in bone tissue, even into deeper regions, (2) to significantly decrease the pH in CAP-exposed bone tissue, (3) to induce a long-lasting and modulable NO production in the bone samples as well as (4) to significantly protect the treated bone tissue against bacterial contaminations, and to induce a strong bactericidal effect in bacterially infected bone samples. Our results strongly suggest that the current DBD technology opens up effective NO-based therapy options in the treatment of local bacterial infections of the bone tissue through the possibility of a targeted modulation of the NOD content in the generated CAPs.

Mucoadhesive chitosan-methylcellulose oral patches for the treatment of local mouth bacterial infections.

Mucoadhesive buccal patches are dosage forms promising for successful drug delivery. They show the distinctive advantages of long residence time on the oral mucosa and increased in situ drug bioavailability. In this context, electrophoretic deposition (EPD) of chitosan (CS) has been demonstrated as a simple and easily tunable technique to produce mucoadhesive buccal patches. However, CS-based buccal patches may suffer from weak mucoadhesion, which can impair their therapeutic effect. In this work, methylcellulose (MC), a widely investigated biopolymer in the biomedical area, was exploited to increase the mucoadhesive characteristic of pristine CS patches. CS-MC patches were obtained in a one-pot process via EPD, and the possibility of incorporating gentamicin sulfate (GS) as a model of a broad-spectrum antibiotic in the so-obtained patches was investigated. The resulting CS-MC patches showed high stability in a water environment and superior mucoadhesive characteristic (σadh = 0.85 ± 0.26 kPa, Wadh = 1192.28 ± 602.36 Pa mm) when compared with the CS control samples (σadh = 0.42 ± 0.22 kPa, Wadh = 343.13 ± 268.89 Pa mm), due to both the control of the patch porosity and the bioadhesive nature of MC. Furthermore, GS-loaded patches showed no in vitro cytotoxic effects by challenging L929 cells with material extracts and noteworthy antibacterial activity on both Gram-positive and Gram-negative bacterial strains.