Cagla Celik Yoldas

A smartphone-based microfluidic platform for rapid antibiotic susceptibility testing of carbapenem- and colistin-resistant bacteria within a few hours.

Many phenotypic resistance tests have been developed for Methicillin-resistant Staphylococcus aureus (MRSA), but they still have disadvantages such as long incubation times, complicated procedure and a lack of portability. Herein, we designed ready-to-use microfluidic chips to use more advanced and new methods for analyzing antibiotic resistance specifically for the rapid detection of MRSA. Anthocyanin molecules, which change color depending on the pH value of the reaction medium in the microfluidic chip wells, are utilized as pH indicator in the test. The color change in the wells depends on the inhibition of antibiotic-resistant or susceptible bacteria at varying cefoxitin doses. The antibiotic resistance profiles of MRSA to multiple doses were revealed on a single chip. The obtained colorimetric responses were analyzed using a mobile application and color image processing techniques. The feasibility of the system was demonstrated using standard reference strains (S. aureus ATCC 43300 and ATCC 25923). Thus, this proof-of-concept study shows that antibiotic resistance detection can be performed in a few hours with minimal device requirements, warranting further validation with clinical isolates.

The rapid and cost-effective identification of Streptococcus pneumoniae (S. pneumoniae) is crucial for the prompt treatment of pneumonia and meningitis. However, conventional culture methods are time-consuming and molecular techniques are prohibitively expensive in resource-limited settings. To address this challenge, we developed a novel anthocyanin chromogenic agar as a diagnostic tool for the selective and rapid detection of S. pneumoniae. Unlike traditional pH-based indicators, this method exploits the unique oxidative capability of S. pneumoniae, which releases excessive amounts of hydrogen peroxide (H₂O₂). This results in the oxidative degradation of the blue anthocyanin pigment to a colorless form, creating distinct gray zones. The detection efficiency was evaluated as a function of bacterial concentration and incubation time. Upon inoculation at concentrations ranging from 1 to 1000 CFU/mL, color changes were monitored visually over 24 h. Notably, an inoculum of 1000 CFU/mL produced visible gray spots within just 7 h of incubation. The anthocyanin chromogenic agar demonstrated high selectivity against common coexisting pathogens, which caused a pH-dependent color change from blue to pink, whereas only S. pneumoniae induced the specific gray signal. Furthermore, colorimetric results were analyzed using digital image processing for objective detection and differentiation. In conclusion, anthocyanin chromogenic agar presents a clinically applicable alternative that significantly reduces both incubation time and cost compared to other chromogenic agars. While the standardization of natural anthocyanin stability remains a consideration for commercial upscaling, this method offers a promising perspective for decentralized testing in resource-limited settings.

The increase in antimicrobial resistance necessitates the development of new therapeutics. In this context, silver nanoparticles (AgNPs) show considerable promise due to their multiple antimicrobial mechanisms, including cell wall disruption, oxidative stress, and DNA damage, as well as their relatively low toxicity. The effectiveness of AgNPs depends on their size, shape, and surface modifications; their combination with ligands can also produce synergistic effects. In this study, cloxacillin sodium (a β-lactam antibiotic) was employed as a ligand to synthesize Clox@AgNPs under UV (311 nm) irradiation using a photo-reduction method. The characteristic absorbance peak, morphology, surface charge, and diameter of the Clox@AgNPs were analyzed using UV–visible spectroscopy, scanning transmission electron microscopy, fourier-transform infrared spectroscopy, dynamic light scattering and zeta potential analyses. The antibacterial activity of the Clox@AgNPs against methicillin-resistant Staphylococcus aureus (MRSA) was then evaluated to enhance the efficacy of existing antibiotics. This approach may provide a valuable contribution to future antimicrobial strategies.

H ₂ O ₂ -triggered anthocyanin degradation enables rapid, instrument-light S. pneumoniae screening with objective Δ E image readout.

Purpose: The aim of this study is to synthesize hybrid nanocomposites from various DNA sequences and to investigate their peroxidase mimic activities.Method: The DNA sequences were used as the organic component and the copper (II) ions were used as the inorganic component for the synthesis. The effect of different synthesis conditions (pH and concentration) on morphology was investigated using a scanning electron microscope. Additionally, the peroxidase mimic activity of nanocomposites was examined.Findings: DNA sequences coded as C20, C20A and C20AA were used at various concentrations within three synthesis environments with different pH levels. This resulted in the formation of flower-like hybrid nanocomposite structures. These structures also exhibited effective peroxidase mimic activity.Conclusion: Various DNA hybrid nanocomposites can be synthesised successfully. These nanocomposites could be used in DNA-related drug delivery systems.

Hybrid nanoflowers synthesized from proteins, enzymes, amino acids and various plant extracts have attracted considerable interest and are used for a variety of purposes. Notably, they exhibit increased stability, as well as enhanced catalytic, antimicrobial and antioxidant activity compared to free molecules. Most synthesis techniques are expected to occur in a solution medium. In this study, we synthesized catecholamine hybrid nanoflowers in situ as a result of a one-day incubation. The in situ catecholamine nanoflower that we synthesized on the surface of a glass exhibits high antimicrobial activity. Thanks to this feature, they have the potential to be used as antimicrobial surface coatings. For surface-bound synthesis, we selected a glass surface as the model surface and catecholamines (dopamine, epinephrine and norepinephrine) as the model organic components. We characterized the in situ catecholamine nanoflower using Scanning Electron Microscopy and contact angle analysis. Additionally, we tested the antimicrobial activities of the in situ catecholamine nanoflower coating against the bacteria Staphylococcus aureus and Escherichia coli and the fungus Candida albicans. The results revealed that the antimicrobial activity of the in situ catecholamine nanoflower coatings had increased significantly. In view of the findings, it is expected that they will have a successful impact as part of antimicrobial surface coatings.

Staphylococcus aureus (S. aureus), which is a member of Micrococcacease family, is one of the most dangerous disease-causing bacteria. S. aureus is also the biggest factor causing hospital-acquired infections worldwide, as well as life-threatening infections such as meningitis, septicaemia, and suppurating wounds in the human body. Today, there have been various phenotypic and/or genotypic methods for the detection of both S. aureus and methicillin-resistant S. aureus (MRSA) strains. Although genotypic methods have been commonly used for certain and rapid results, they are quite expensive and rarely available in all hospitals; they need costly and complicated devices and expert use. To address these issues, researchers have recently developed nanomaterials (NMs) and organic molecules-based phenotypic methods for rapid, sensitive, and economical detection of S. aureus and MRSA. We focus on evaluating colorimetric assays using NMs and pH indicator-containing tests for the rapid, sensitive, and cost-effective detection of S. aureus and MRSA, and specifically target their application in both clinical and environmental contexts.

Background/aim: Neuropathic pain (NP) is a type of chronic pain usually caused by damage to the somatosensory system. Bioactive antioxidant compounds, such as curcumin and ginger, are widely preferred in the treatment of NP. However, the ingredient-based mechanism that underlies their pain-relieving activity remains unknown. The aim of this study was to investigate the therapeutic effects of trans-[6]-Shogaol and [6]-Gingerol active ingredients of the Zingiber officinale Roscoe extract on the spinal cord and cortex in the neuroinflammatory pathway in rats with experimental sciatic nerve injury. Materials and methods: Forty-six volatile phenolic components were identified in ginger samples using gas chromatography-mass spectrometry analysis. Thirty 3-month-old male 250-300 g Wistar Albino rats were divided into three groups as (i) sham, (ii) chronic constriction injury (CCI), and (iii) CCI+ginger. NP was induced using the CCI model. A ginger extract treatment enriched with trans-[6]-shogaol and [6]-gingerol active ingredients was administered by gavage at 200 mg/kg/day for 7 days. On the 14th day of the experiment, locomotor activity was evaluated in open field and hyperalgesia in tail flick tests. Results: In behavioural experiments, a significant decrease was observed in the CCI group compared to the sham group, while a significant increase was observed in the CCI+ginger group compared to the CCI group (p < 0.05). In the spinal cord and cortex tissues, there was a significant increase in the TNF-α, IL-1ß, and IL-18 neuroinflammation results of the CCI group compared to the sham group, while there was a significant decrease in the CCI+ginger group compared to the CCI group. Conclusion: In this study, ginger treatment was shown to have a therapeutic effect on neuroinflammation against sciatic nerve damage.

Objective The purpose in the study was to evaluate the effect of biogenic silver nanoparticles (Ag NPs) synthesized by the green synthesis method on dentin bond strength in three different universal adhesives and investigate their antibiofilm activity against Streptococcus mutans (S. mutans). Materials and methods Three different universal adhesives (single bond universal, all-bond universal, and clearfil universal) were used in this study. Ag NPs were synthesized using rose hip (Rosa canina) extract as a reducing and stabilizing agent and they were characterized with STEM, UV–vis spectrophotometer, DLS, and zeta potential. Ag NPs were added to the adhesive resins at a rate of 0.05% (w/w), and their homogeneous distribution in the adhesive was determined using EDX spectrometry. Samples in all groups were tested at baseline-after 5000 and 10,000 thermal cycles. Adhesive composite discs were used for the live/dead analysis of S. mutans, MTT metabolic activity test, lactic acid production, and determination of colony-forming unit (CFU) values (n = 3). Ninety extracted caries-free human third molars were used to determine microtensile bond strength (μTBS) (n = 10). After the universal adhesive was applied to the dentin surface, composite resin (Z550 XT, 3 M ESPE, USA) was placed and sections were taken to form a composite-dentin stick of 1 mm × 1 mm wideness and 8-mm length. The sticks were broken at a rate of 1 mm/min under uniaxial tension in a universal testing machine, and the failure modes were determined by SEM. One-way analysis of variance (ANOVA) for antibacterial tests and two-way analysis of variance for μTBS tests were performed (p < 0.05). Results All universal adhesive groups containing Ag NPs showed higher antibacterial activity than control groups without Ag NPs (p < 0.05). There was a statistically significant difference in the live/dead assay analysis, MTT metabolic activity test, lactic acid production, and CFU values in the thermal cycled Ag NPs groups (p < 0.05). Antibacterial activity decreased in groups containing Ag NPs subjected to 10,000 thermal cycles. The highest lactic acid production 11.06 (± 0.629) and CFUs 7.61 (± 0.304), live bacteria 31.13 (± 0.466), and S. mutans MTT metabolic activity 0.29 (± 0.376) at AU (All-Bond Universal—Ag NPs) 10,000 thermal cycles group. There was no difference in μTBS values between the initial and 5000 thermal cycle groups, there was a difference between the 10,000 thermal cycle groups. The CU (Clearfil Universal—Ag NPs) group subjected to 10,000 thermal cycles showed lower μTBS 11.1 (± 3.2). Conclusion In conclusion, universal adhesives containing biogenic Ag NPs showed higher antibacterial activity than the control groups and did not reduce the μTBS. Clinical relevance Antibacterial universal adhesives can contribute to restoration success in clinical applications by reducing residual bacteria and preventing secondary caries formation.