Application of the MTT-based colorimetric method for evaluating bacterial growth using different solvent systems

In vitro analysis of XLAsp-P2 peptide loaded cellulose acetate nanofiber for wound healing

Recently, nanofiber-based wound dressings are currently a viable strategy to expedite the healing of wounds by providing a suitable microenvironment for tissue growth with active ingredients. This research study subjects the development of electrospun cellulose acetate (CA) nanofibers loaded with the XLAsp-P2, an antimicrobial peptide (AMP) that holds great potential for enhanced wound healing as a therapeutic agent. The synthesized XLAsp-P2-loaded CA nanofibers were fabricated via three loading percentages, 0.1 %, 0.2 %, and 0.3 % w/w, and characterized and evaluated their antimicrobial potential with MTT assay and Agar overlay methods as an alternative strategy. FT-IR analysis confirmed the compatibility of the peptide-loaded CA nanocomposite, showing distinct peaks corresponding to the constituent materials. Scanning electron microscopy (SEM) analysis was employed to characterize the morphology of electrospun peptide CA nanocomposites and illustrate the fiber's size at the nanoscale. The in vitro release study during the 24 hr, 87 % of the peptide was released which was approximately 5.2 mg; which was closer matched to the square root model of Higuchi at room temperature. MTT assay presented sensitive results towards Gram-positive bacteria compared to Gram Negative bacteria; which corresponded to the inhibition zones of the Agar overlay method proving that Escherichia coli (ATCC 25922) 17.66 ± 0.38 mm and Pseudomonas aeruginosa (ATCC 27853) 17.44 ± 0.38 mm exhibited moderate susceptibility, while Staphylococcus aureus (ATCC 25923)19.89 ± 0.69 mm and Bacillus cereus (ATCC 11778) 23.00 ± 0.33 mm showed promising responses. Collectively, The study's findings indicate that the XLAsp-P2 incorporated CA mat possesses an opportunity to function as an efficient platform for delivering therapeutic peptides.

Novel ZnO-TiO2@MSC nanomaterial based on corn stover template enhances disease resistance in tomato plants

Crop diseases significantly threaten global food security, driving the need for innovative control strategies. This study explored using ZnO-TiO2@MSC, a novel nanomaterial synthesized using a corn stover template, to enhance disease resistance in tomato plants. In vitro assays demonstrated potent antimicrobial activity of ZnO-TiO2@MSC against the pathogen Pseudomonas syringae pv. tomato DC3000 (Pst. DC3000) by disrupting bacterial cell membranes and modulating oxidative stress-related gene expression. When applied to tomato leaves in pot trials, ZnO-TiO2@MSC achieved 79.83% control of bacterial leaf spot disease while promoting plant growth and photosynthesis. The nanomaterial triggered plant defense mechanisms, upregulating resistance genes and increasing the activities of key enzymes. Metabolomic profiling revealed elevated lipids, lipid-like molecules, and organic acid derivative levels in treated leaves, suggesting cell membrane remodeling as part of the defense response. These findings highlight the potential of biologically-templated nanomaterials like ZnO-TiO2@MSC as multifunctional tools for sustainable disease management in crops. The corn stover-based synthesis approach also provides a way to valorize agricultural waste. Further research is needed to understand the long-term impacts and viability of field-scale application of ZnO-TiO2@MSC as an alternative to conventional pesticides.

Epidemiological and genetic charateristics of Vibrio vulnificus from diverse sources in China during 2012-2023

Vibrio vulnificus is a significant zoonotic pathogen that causes severe vibriosis in humans and fish. The lack of a national annual surveillance program in China has hindered understanding of its epidemiological characteristics and genetic diversity. This study characterized 150 V. vulnificus isolates collected from diverse sources in China during 2012-2023, including seafood, aquaculture water, migratory birds, marine animals, and clinical patients. Most seafood-derived isolates and all 15 clinical isolates harbored the virulence-related gene vcgC and 16S rRNA type B. The isolates exhibited diverse virulence factors (VFs), including flagella, outer membrane components, RTX toxins, and multiple secretion systems. Genes associated with the Type III secretion system were identified in migratory bird isolates, while a unique Type VI secretion system (T6SS1) were identified exclusively within a specific phylogenetic sub-lineage. T6SS1-positive strains demonstrated an increased number of genomic islands (GIs) and VFs compared to T6SS1-negative strains. Enrichment of genes related to secretion systems and biofilm formation likely facilitated the expansion of the T6SS1-positive population. The novel association between T6SS1 and a specific sub-lineage underscores potential ecological and adaptive advantages. These findings provide new insights into the ecological and evolutionary dynamics of V. vulnificus.

Screening of antimicrobial activity in venom: Exploring key parameters

The escalating challenge of antibiotic resistance significantly threatens global health, underscoring the critical need for new antimicrobial agents. Venoms, increasingly recognized as reservoirs of bioactive compounds with diverse pharmacological effects, have been the focus of recent research. This work evaluates the use of various screening methodologies in assessing the antimicrobial activities of 185 venoms against some gram positive and gram negative bacteria, including E. coli ATCC 8739, B. subtilis ATCC 6633, P. aeruginosa ATCC 9027, and S. aureus ATCC 6538P species and explores the influence of settings on the findings. Furthermore, the research explored the possibility of purifying antimicrobial molecules from venoms through HPLC. Several fractions demonstrated antimicrobial activity against the tested strains. Our results reveal that the measured antimicrobial efficacy of venoms varies according to:i) venom concentration, ii) the detection method, including microdilution and radial diffusion assays, and iii) the choice of culture medium, specifically LB or MH. This strategy has allowed us, for the first time, to identify antimicrobial activity in: i) Bitis arietans venom against P. aeruginosa ATCC 9027, ii) Naja nubiae and Bothrops lanceolatus against B. subtilis ATCC 6633, P. aeruginosa ATCC 9027, and S. aureus ATCC 6538P, and iii) Hadogenes zuluanus, Mesobuthus caucasicus, Nebo hierichonticus, Opistophthalmus wahlbergii scorpions, and Mylabris quadripunctata beetles against S. aureus ATCC 6538P. These findings highlight venoms potential as effective antimicrobial resources and improve our understanding of key factors critical for an accurate detection of venoms antimicrobial properties.

Bio-based polylactic acid labware as a sustainable alternative for microbial cultivation in life science laboratories

Single-use plastics (SUPs) in life science laboratories account for approximately 5.5 million tonnes of waste per year globally. Of SUPs used in life science laboratories, Petri dishes, centrifuge tubes, and inoculation loops are some of the most common. In order to reduce the reliance on petrochemical-based SUPs in the life science research laboratory and minimize the negative environmental impacts associated with SUPs, this research investigates the applicability of polylactic acid (PLA) in single-use labware as a replacement for petrochemical-based plastics. PLA is one of the most well-studied biodegradable plastics that can be produced from sustainable resources. Commercially available PLA was used to 3D print a select range of labware to test the suitability of PLA-based material for routine microbiology work. An injection moulded PLA-based Petri dish was also designed and produced, for increased optical clarity. The biocompatibility was tested against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus epidermidis) strains of bacteria. The PLA-based labware did not negatively impact the cell growth, viability, and metabolic activity of the bacterial cultures. The injection moulded PLA Petri dish showed a reduced colony forming unit count for the Gram-negative E. coli strain compared to the polystyrene Petri dish, ∼1.5 × 109 CFU/mL and ∼3.0 × 109 CFU/mL respectively, during late-exponential growth. The colony counts were, however, in the same order of magnitude. This observed difference may be due to the internal environment inside the Petri dish, hence the internal O2 concentration, humidity, and temperature during bacterial growth were investigated. This work demonstrates, for the first time, a full successful workflow of bacterial growth using a sustainable bioplastic, providing a pathway to reducing the environmental impacts of SUPs in life science laboratories.

Activated carbon-coated iron oxide magnetic nanocomposite (IONPs@CtAC) loaded with morin hydrate for drug-delivery applications

Cancer is a major disease that affects millions of people around the world every year. It affects individuals of all ages, races, and backgrounds. Since drugs used to treat cancer cannot distinguish between cancerous and healthy cells, they cause systemic toxicity along with serious side effects. Recently, controlled drug-release systems have been developed to reduce the side effects caused by anticancer drugs used for treatment. Morin is an anticancer drug with a flavonol structure. It has been extensively researched for its antioxidant, anti-inflammatory, antitumoral, and antibacterial properties, especially found in Chinese herbs and fruits, and its multiple positive effects on different diseases. In this study, a nanocomposite with magnetic properties was synthesized by coating biocompatible activated carbon obtained using the fruits of the Celtis tournefortii plant on the surface of iron oxide magnetic nanoparticles. Characterization of the synthesized activated carbon-coated iron oxide magnetic nanocomposite was confirmed by Fourier transform infrared, scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffraction, dynamic light scattering, zeta potential, and vibrating sample magnetometry. The cytotoxic effects of the drug-loaded magnetic nanocomposite were examined in HT-29 (colorectal), T98-G (glioblastoma) cancer cell lines, and human umbilical vein endothelial cell (HUVEC) healthy cell line. The morin loading and release behavior of the activated carbon-coated iron oxide magnetic nanocomposite were studied, and the results showed that up to 60% of the adsorbed morin was released within 4 h. In summary, activated carbon-coated iron oxide magnetic nanocomposite carriers have shown promising results for the delivery of the morin drug.

In vitro antibacterial, antibiofilm activities, and phytochemical properties of Posidonia oceanica (L.) Delile: An endemic Mediterranean seagrass

In the antibiotic resistance era, utilizing understudied sources for novel antimicrobials or antivirulence agents can provide new advances against antimicrobial resistant pathogens. In this study, we aimed to investigate antibacterial and antibiofilm activities of Posidonia oceanica (L.) Delile against Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Klebsiella pneumoniae ATCC 700603 and several S. aureus clinical isolates obtained from medical devices, including patient urinary catheters and breast implant infections, with varying antibiotic recalcitrance profiles. The ethanolic and methanolic extracts from P. oceanica rhizome exhibited significant antibacterial activity against E. faecalis and S. aureus, as well as drug resistant S. aureus clinical isolates. Furthermore, significant antibiofilm activity was observed against S. aureus and E. faecalis treated with ER, MR1, and MR2. P. oceanica extracts also exhibited synergistic antimicrobial activity with ciprofloxacin against E. faecalis, sensitizing E. faecalis to a lower ciprofloxacin concentration. Collectively, our data demonstrate the selective antibacterial and antibiofilm activity of the extracts of P. oceanica against Gram-positive bacteria and clinical isolates along with potentiation of current antibiotics, which suggests that P. oceanica can be further investigated as a potential source for novel therapeutic options in the treatment of drug resistant bacterial infections.

Analysis of the broad-spectrum potential of nitric oxide for antibacterial activity against clinically isolated drug-resistant bacteria

The development of drug-resistant microorganisms is taking a heavy toll on the biomedical world. Clinical infections are costly and becoming increasingly dangerous as bacteria that once responded to standard antibiotic treatment are developing resistance mechanisms that require innovative treatment strategies. Nitric oxide (NO) is a gaseous molecule produced endogenously that has shown potent antibacterial capabilities in numerous research studies. Its multimechanistic antibacterial methods prevent the development of resistance and have shown potential as an alternative to antibiotics. However, there has yet to be a direct comparison study evaluating the antibacterial properties of NO against antibiotic susceptible and antibiotic-resistant clinically isolated bacterial strains. Herein, standardized lab and clinically isolated drug-resistant bacterial strains are compared side-by-side for growth and viability following treatment with NO released from S-nitrosoglutathione (GSNO), an NO donor molecule. Evaluation of growth kinetics revealed complete killing of E. coli lab and clinical strains at 17.5 mM GSNO, though 15 mM displayed >50% killing and significantly reduced metabolic activity, with greater dose dependence for membrane permeability. Clinical P. aeruginosa showed greater susceptibility to GSNO during growth curve studies, but metabolic activity and membrane permeability demonstrated similar effects for 12.5 mM GSNO treatment of lab and clinical strains. MRSA lab and clinical strains exhibited total killing at 17.5 mM treatment, though metabolic activity was decreased, and membrane permeation began at 12.5 mM for both strains. Lastly, both S. epidermidis strains were killed by 15 mM GSNO, with sensitivities in metabolic activity and membrane permeability at 12.5 mM GSNO. The mirrored antibacterial effects seen by the lab and clinical strains of two Gram-negative and two Gram-positive bacteria reveal the translational success of NO as an antibacterial therapy and potential alternative to standard antibiotic treatment.

Development of a Convenient and Quantitative Method for Evaluating Photosensitizing Activity Using Thiazolyl Blue Formazan Dye

Photosensitizers cause oxidative damages in various biological systems under light. In this study, the method for analyzing photosensitizing activity of various dietary and medicinal sources was developed using 1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan (thiazolyl blue formazan; MTT-F) as a probe. Significant and quantitative decolorization of MTT-F was observed in the presence of photosensitizers used in this study under light but not under dark conditions. The decolorization of MTT-F occurred irradiation time-, light intensity-, and photosensitizer concentration-dependently. The decolorized MTT-F was reversibly reduced by living cells; the LC-MS/MS results indicated the formation of oxidized products with -1 m/z of base peak from MTT-F, suggesting that MTT-F decolorized by photosensitizers was its corresponding tetrazolium. The present results indicate that MTT-F is a reliable probe for the quantitative analysis of photosensitizing activities, and the MTT-F-based method can be an useful tool for screening and evaluating photosensitizing properties of various compounds used in many industrial purposes.

Dual-modified starch as particulate emulsifier for Pickering emulsion: Structure, safety properties, and application for encapsulating curcumin

In this study, cinnamic acid modified acid-ethanol hydrolyzed starch (CAES) with different degrees of substitution (DS) was fabricated to stabilize Pickering emulsions and probed their application for encapsulating curcumin (Cur). Successful preparation of CAES (with DS from 0.016 to 0.191) was confirmed by 1H NMR and FT-IR, and their physicochemical properties were characterized by XRD, SEM, and TGA. The biosafety evaluations and surface wettability confirmed the excellent safety and amphiphilic character of CAES. CAES-stabilized Pickering emulsion (CS-PE) exhibited different emulsion stability at different DS, with CS-PE (0.031) showing the highest stability. CLSM revealed that the CAES (0.031) formed a dense barrier on the surface of the oil droplets, preventing them from coalescing. The CS-PE (0.031) achieved effective encapsulation of Cur (up to 96.2 %). Compared with free Cur, CS-PE (0.031) exhibited better photochemical stability, higher free fatty acids (FFA) release, and enhanced bioaccessibility. These studies suggested that CAES may serve as a promising emulsifier for stabilizing Pickering emulsions to encapsulate and deliver hydrophobic bioactive compounds.

Biodegradation of Trichloroethylene by Trametes versicolor and its Physiological Response to Contaminant Stress

Trichloroethylene (TCE) poses a potentially toxic threat to humans and the environment and widely exists in contaminated sites. White rot fungi effectively degrade refractory pollutants, while a few research studies use white rot fungi to degrade TCE. In this study, we investigated TCE biodegradation by white rot fungi and the potential influencing factors in the environment and attempted to research the effect of TCE on the physiological characteristics of white rot fungi. White rot fungi (Trametes versicolor, Pseudotrametes gibbosa, Pycnoporus sanguines and Pleurotus ostreatus) were added to the liquid medium for shock culture. The results revealed that T. versicolor exhibited the most pronounced efficacy in removing TCE, with a degradation rate of 81.10% within a 7 d period. TCE induces and is degraded by cytochrome P450 enzymes. High pH and Cr(VI) adversely affected the effectiveness of the biodegradation of TCE, but the salinity range of 0-1% had less effect on biodegradation. Overall, the effectiveness of degradation of TCE by T. versicolor has been demonstrated, and it provides a reference for the application prospects of white rot fungi in TCE-contaminated soils.

Saponaria officinalis saponins as a factor increasing permeability of Candida yeasts' biomembrane

Saponins are a large group of compounds, produced mostly by plants as a side product of their metabolic activity. These compounds have attracted much attention over the years mostly because of their surface activity and antibacterial, anti-inflammatory and antifungal properties. On the other hand, most of the hitherto research has concerned the action of saponins against microbial cells as a whole. Therefore, knowing the possible interaction of saponins with biomembrane, we decided to check in-vitro the influence of saponin-rich extract of Saponaria officinalis on spheroplasts of two Candida sp. The obtained results show that 10 mg L- 1 of extract increased the permeability of spheroplasts up to 21.76% relative to that of the control sample. Moreover, the evaluation of surface potential has revealed a decrease by almost 10 mV relative to that of the untreated samples. Such results suggest its direct correlation to integration of saponins into the biomembrane structure. The obtained results have proved the antifungal potential of saponins and their ability of permeabilization of cells. This proves the high potential of saponins use as additives to antifungal pharmaceutics, which is expected to lead to improvement of their action or reduction of required dosage.

α-Amylase purified and characterized from fenugreek (Trigonella foenum-graecum) showed substantial anti-biofilm activity against Staphylococcus aureus MTCC740

Starch hydrolyzing α-amylase from germinated fenugreek (Trigonella foenum-graecum) has been purified 104-fold to apparent electrophoretic homogeneity with a final specific activity of 297.5 units/mg. SDS-PAGE of the final preparation revealed a single protein band of 47.5 kDa, supported by LC/MS analysis and size-exclusion chromatography on the Superdex 200 (ÄKTA-FPLC). α-Amylase exhibited maximum activity at pH 5.5. An activation energy (Ea) of 9.12 kcal/mol was found to exist in the temperature range of 20 to 90 °C. When substrate concentrations were evaluated between 0.5 and 10 mg/mL, the Km and Vmax values for starch were observed to be 1.12 mg/mL and 384.14 μmol/min/mg, respectively. The major substrate starch exhibited high specificity for fenugreek α-amylase. In the presence of EDTA (5 mM), the activity was lost, however, it could be largely reversed with the addition of calcium. Furthermore, an effort was made to assess the ability of fenugreek seed-derived partially purified (DEAE-cellulose enzyme) and purified α-amylase to disperse inside 48 h-old biofilms of Staphylococcus aureus MTCC740. The outcomes clearly demonstrated that the purified and partially purified α-amylase both exhibited strong biofilm dispersion activity.

Study on the transport and internalisation mechanism of dietary supplement nattokinase in the small intestine using animal and Caco-2 cell monolayer models

Maintaining proper blood flow is critical to promoting good health. Nattokinase is a serine protease from Bacillus subtilis that has significant in vitro thrombolytic activity, but its mechanism as a dietary supplement to prevent thrombosis through intestinal absorption and transport is still unclear.The purpose of this study is to study the transport and internalisation mechanism of NK in the small intestine using animal models and Caco-2 cell monolayer models.This study first evaluated the preventive effect of supplementing low dose (4000 FU (Fibrin Unit)/kg, n = 6), medium dose (8000 FU/kg, n = 6), and high dose (12000 FU/kg, n = 6) of nattokinase on carrageenan induced thrombosis in mice. Subsequently, we used the rat gut sac model, ligated intestinal loop model, and Caco-2 cell uptake model to study the intestinal transport mechanism of NK.Results indicate that NK is a moderately absorbed biomolecule whose transport through enterocytes is energy- and time-dependent. Chlorpromazine, nystatin and EIPA all inhibited the endocytosis of NK to varying degrees, indicating that the endocytosis of NK in Caco-2 cells involves macropinocytosis, clathrin-mediated and caveolae-mediated pathway. These findings offer a theoretical basis for investigating the mechanism of oral NK supplementation in greater depth.

Transition Metal High-Entropy Nanozyme: Multi-Site Orbital Coupling Modulated High-Efficiency Peroxidase Mimics

Strong substrate affinity and high catalytic efficiency are persistently pursued to generate high-performance nanozymes. Herein, with unique surface atomic configurations and distinct d-orbital coupling features of different metal components, a class of highly efficient MnFeCoNiCu transition metal high-entropy nanozymes (HEzymes) is prepared for the first time. Density functional theory calculations demonstrate that improved d-orbital coupling between different metals increases the electron density near the Fermi energy level (EF ) and shifts the position of the overall d-band center with respect to EF , thereby boosting the efficiency of site-to-site electron transfer while also enhancing the adsorption of oxygen intermediates during catalysis. As such, the proposed HEzymes exhibit superior substrate affinities and catalytic efficiencies comparable to that of natural horseradish peroxidase (HRP). Finally, HEzymes with superb peroxidase (POD)-like activity are used in biosensing and antibacterial applications. These results suggest that HEzymes have great potential as new-generation nanozymes.

An improved MTT colorimetric method for rapid viable bacteria counting

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay has been employed in the analysis of bacterial growth. In comparison to experiments conducted on mammalian cells, the MTT bacterial assay encounters a greater number of interfering factors and obstacles that impact the accuracy of results. In this study, we have elucidated an improved MTT assay protocol and put forth an equation that establishes a correlation between colony-forming units (CFU) and the amount of formazan converted by the bacteria, drawing upon the fundamental principle of the MTT assay. This equation is represented as CFU=kF. Furthermore, we have explicated a methodology to determine the scale factor "k" by employing S. aureus and E. coli as illustrative examples. The findings indicate that S. aureus and E. coli reduce MTT by a cyclic process, from which the optimal reduction time at room temperature was determined to be approximately 30 mins. Furthermore, individual E. coli exhibits an MTT reduction capacity approximately four times greater than that of S. aureus. HPLC analysis proves to be the most accurate method for mitigating interferences during the dissolution and quantification of formazan. Additionally, this study has identified a new constraint related to the narrow linear range (0-125 μg/mL) of formazan concentration-absorbance and has presented strategies to circumvent this limitation.

Chemical Profiling and Biological Activity of Psydrax dicoccos Gaertn

Breast cancer is one of the deadliest diseases in women with a mortality rate of 6.6%. Adverse effects of synthetic drugs have directed research toward safer alternatives such as natural compounds. This study focused on Psydrax dicoccos Gaertn, an evergreen tree abundantly distributed in Tamil Nadu (India) for its possible application against breast cancer cells. P. dicoccos leaf methanol extract, found within a wide range of phytochemicals, demonstrated cytotoxic effects against MCF7 breast cancer cells at IC50 of 34 μg/mL. The extract exhibited good antioxidant activities against DPPH• (62%) and ABTS•+ (80%), as well as concentration-dependent (100-800 μg/mL) anti-inflammatory potential of 18-60% compared to standards, ascorbic acid or aspirin, respectively. Moreover, even low extract concentrations (10 μg/mL) inhibited the growth of Escherichia coli (1.9 ± 0.6 mm) and Pseudomonas aeruginosa (2.3 ± 0.7 mm), thus showing high antimicrobial and anti-inflammatory potential. GC-MS and LC-MS analyses identified 31 and 16 components, respectively, of which selected compounds were used to evaluate the interaction between key receptors (AKT-1, COX-2, and HER-2) of breast cancer based on binding energy (ΔG) and inhibition constant (Ki). The results indicate that bioactive compounds from P. dicoccos have potential against breast cancer cells, but further evaluations are needed.

Efficient encapsulation of fat-soluble food-derived biofunctional substances (curcumin as an example) in dual-modified starch-based nanoparticles containing large conjugated systems

Acid-ethanol hydrolysis and subsequent cinnamic acid (CA) esterification were employed to prepare a series of dual-modified starches efficiently loaded with curcumin (Cur) utilizing large conjugation systems provided by CA. Structures of the dual-modified starches were confirmed by IR and NMR, and their physicochemical properties were characterized by SEM, XRD and TGA. The nanoparticles fabricated from the dual-modified starch have perfect spherical shape (250.7-448.5 nm, polydispersity index <0.3), excellent biosafety (no hematotoxicity, no cytotoxicity, no mutagenicity) and high loading of Cur (up to 26.7 % loading). By XPS analysis, this high loading is believed to be supported by the synergistic effect of hydrogen bonding (provided by hydroxyl groups) and π-π interactions (provided by large conjugation system). In addition, the encapsulation of dual-modified starch nanoparticles effectively enhanced the water solubility (18-fold) and physical stability (6-8-fold) of free Cur. In vitro gastrointestinal release showed that Cur-encapsulated dual-modified starch nanoparticles were released more preferably than free Cur and that the Korsmeyer-Peppas model was the most suitable release model. These studies suggest that dual-modified starches containing large conjugation systems would be a better alternative for encapsulating fat-soluble food-derived biofunctional substances in functional food and pharmaceutical applications.

Triple-function chitosan-based film for pork and shrimp packaging

A film simultaneously with colorimetric, fluorescent and active functions was engineered using chitosan (CS) and polyvinyl alcohol (PVA) as the film matrix and curcumin-β-cyclodextrin complex (Cur-β-CD) as the indicator for freshness monitoring and maintaining of pork and shrimp. In addition to the efficacy of prolonging shelf life, the film's color could change from yellow to orange with ΔE > 5 and its fluorescence intensity could decrease during storage. The incorporation of PVA significantly enhanced the mechanical properties of CS film with tensile strength of 31.80 MPa and elongation at break of 127.22 %. The Cur-β-CD improved the antioxidant and antibacterial properties, water contact angle (from 86.3° to 111.2°), water vapor permeability (from 3.28 × 10^-10 g (m s Pa)^-1 to 0.42 × 10^-10 g (m s Pa)^-1) and mechanical properties of CS/PVA film. These results show the potential of the film as promising alternatives for intelligent and active food packaging.

Evaluation of a novel water-soluble decanoic acid formulation as a fruit sanitizer

Fruits irrigated with contaminated water can transmit various pathogens. High sugar content in fruits such as black cherry (BC) fruit encourages microbial proliferation. A novel water-soluble decanoic acid (WSDA) was evaluated as a fruit sanitizer and compared with other traditional fruit sanitizers such as ethanol, bleach, or dishwasher surfactants. WSDA sanitizer killed yeasts, molds and bacteria including E. coli microbes effectively as other sanitizers with (4 log cycle reduction) of microbial load. Furthermore, the bacterial sanitization mechanism i.e. bactericidal or bacteriostatic was evaluated for alcohol, bleaching and WASDA solutions. E. coli was selected as the model pathogen used for such comparison. Results indicated that the mechanism of action for the three sanitizer solutions against E. coli was bactericidal. The problem with most used fruit sanitizers is their negative influence on fruit quality in terms of physical, mechanical and taste properties. In addition, some led to toxicological and ecological concerns. Thus, studies were conducted to explore the changes in the exocarp cell structure of BC fruit upon exposure to WSDA and other sanitizers using microscopic investigation. WSDA could have a very mild or gentle effect on the BC fruit cells compared to other sanitizers. Alcohol, bleaching and dishwasher surfactant changed the cellular structures and the intercellular spaces. Sanitizers may also affect fruit swelling. WSDA showed an increase in percent weight gain but it was significantly (p < 0.05) much lower than dishwasher surfactant and bleaching solution. BC Fruit flesh firmness and hardness were investigated upon exposure to different sanitizer solutions. BC fruit treated with WSDA showed the highest firmness values. Some liquid sanitizers could affect fruit quality in terms of fruit taste. Sensory evaluation in terms of the sanitizer's smell, texture and hedonic of BC fruit after soaking in different sanitizers was carried out. All sensory parameters of BC fruit soaked with WSDA were similar with insignificant differences (p > 0.05) compared to BC fruit soaked in tap water. However, the sensory parameters were significantly different (p < 0.05) when compared with alcohol, bleach and dishwasher surfactant. This ensures that WSDA was superior to other evaluated sanitizers in terms of physical, mechanical and fruit quality.

High-accuracy gastric cancer cell viability evaluation based on multi-impedance spectrum characteristics

The increasing attention to precision medicine is widely paid to greatly rise the cure rate of cancer. Improving the stability and accuracy of cancer cell viability evaluation is one of the keys for precision medicine, as excess dosage of anti-cancer drugs not only kills the cancer cells, but also does harm to normal cells. Electrochemical impedance sensing (EIS) method is well known as a label-free, non-invasive approach for real-time, online monitoring of cell viability. However, the existing EIS methods using single-frequency impedances cannot reflect the comprehensive information of cellular impedance spectroscopy (CIS), ultimately leading to a poor stability and low accuracy of cancer cell viability evaluation. In this paper, we proposed a multi-frequency approach for improving the stability and accuracy of cancer cell viability evaluation based on multi-physical properties of CIS, including cell adhesion state and cell membrane capacitance. The results show that the mean relative error of multi-frequency method is reduced by 50% compared with single-frequency method, while the maximum relative error of the former is 7∼fold smaller than that of the latter. The accuracy of cancer cell viability evaluation is up to 99.6%.

Antibacterial and Antibiofilm Effect of Unifloral Honeys against Bacteria Isolated from Chronic Wound Infections

Honey is known as an alternative remedy for the treatment of wounds. To evaluate the potential of five Hungarian honey types against wound-associated bacteria, in vitro microbiological assays were conducted on Pseudomonas aeruginosa, Staphylococcus epidermidis and methicillin-resistant Staphylococcus aureus (MRSA). Minimum inhibitory concentration (MIC) was determined with the broth macrodilution method, and biofilm degradation capacity was tested with a crystal violet assay. To understand the underlying mechanisms, the effects of honey treatments were assessed on bacterial membrane integrity and quorum sensing (QS). The highest antibacterial activity, indicated by the lowest MIC values, as well as the highest biofilm inhibition rates and membrane disruption, was displayed by chestnut and linden honeys. The most sensitive bacterium was S. epidermidis. Bacterial membrane degradation took place 40 min after treatment with honey solutions of at least a 40% concentration. Each honey sample exhibited anti-QS activity, which was most pronounced in the case of chestnut honey. It was concluded that the antibacterial, biofilm-inhibiting and anti-QS activities of linden and chestnut honeys were superior to those of acacia, goldenrod and milkweed honeys. In addition to the floral source, the antibacterial effect of honey is influenced by the microbial species treated. The use of honey in wound treatment can be justified by its diverse antibacterial mechanisms.

Effect of porosity on mechanical and biological properties of bioprinted scaffolds

Treatment of tissue defects commonly represents a major problem in clinics due to difficulties involving a shortage of donors, inappropriate sizes, abnormal shapes, and immunological rejection. While many scaffold parameters such as pore shape, porosity percentage, and pore connectivity could be adjusted to achieve desired mechanical and biological properties. These parameters are crucial scaffold parameters that can be accurately produced by 3D bioprinting technology based on the damaged tissue. In the present research, the effect of porosity percentage (40%, 50%, and 60%) and different pore shapes (square, star, and gyroid) on the mechanical (e.g., stiffness, compressive and tensile behavior) and biological (e.g., biodegradation, and cell viability) properties of porous polycaprolactone (PCL) scaffolds coated with gelatin have been investigated. Moreover, human foreskin fibroblast cells were cultured on the scaffolds in the in-vitro procedures. MTT assay (4, 7, and 14 days) was utilized to determine the cytotoxicity of the porous scaffolds. It is revealed that the porous scaffolds produced by the bioprinter did not produce a cytotoxic effect. Among all the porous scaffolds, scaffolds with a pore size of about 500 μm and porosity of 50% showed the best cell proliferation compared to the controls after 14 days. The results demonstrated that the pore shape, porosity percentage, and pore connectivity have an important role in improving the mechanical and biological properties of porous scaffolds. These 3D bioprinted biodegradable scaffolds exhibit potential for future application as polymeric scaffolds in hard tissue engineering applications.

Unveiling the therapeutic potential of cabozantinib-loaded poly D,L-lactic-co-glycolic acid and polysarcosine nanoparticles in inducing apoptosis and cytotoxicity in human HepG2 hepatocellular carcinoma cell lines and in vivo anti-tumor activity in SCID female mice

Introduction

The study aimed to develop a nano-based drug delivery system for the treatment of hepatocellular carcinoma (HCC), a type of liver cancer that accounts for 90% of all liver malignancies. The study focused on the use of cabozantinib (CNB), a potent multikinase inhibitor that targets the VEGF receptor 2, as the chemotherapeutic drug. We developed CNB-loaded nanoparticles made from Poly D, L-lactic-co-glycolic acid, and Polysarcosine (CNB-PLGA-PSar-NPs) for use in human HepG2 cell lines.

Methods

By O/W solvent evaporation method, the polymeric nanoparticles were prepared. The various techniques, such as photon correlation spectroscopy, scanning electron microscopy, and transmission electron microscopy were used, to determine the formulation's particle size, zeta potential, and morphology. SYBR Green/ROX qPCR Master Mix and RT-PCR equipment used to measure liver cancer cell line and tissue mRNA expression and MTT assay to test HepG2 cell cytotoxicity. Cell cycle arrest analysis, annexin V assay, and ZE5 Cell Analyzer apoptosis assay were also performed.

Results

The results of the study showed that the particle diameters were 192.0 ± 3.67 nm with 0.128 PDI and -24.18 ± 3.34 mV zeta potential. The antiproliferative and proapoptotic effects of CNB-PLGA-PSar-NPs were evaluated using MTT and flow cytometry (FCM). The IC50 value of CNB-PLGA-PSar-NPs was 45.67 µg/mL, 34.73 µg/mL, and 21.56 µg/mL for 24, 48, and 72 h, respectively. The study also found that 11.20% and 36.77% of CNB-PLGA-PSar-NPs-treated cells were apoptotic at 60 µg/mL and 80 µg/mL, respectively, suggesting that the nanoparticles were effective in inducing apoptosis in the cancer cells. It can also conclude that, CNB-PLGA-PSar-NPs inhibit human HepG2 hepatocellular carcinoma cells and kill them by upregulating the tumour suppressor genes MT1F, MT1X, and downregulating MTTP, APOA4. Further in vivo antitumor activity was well reported in SCID female mice.

Discussion

Overall, this study suggests that the CNB-PLGA-PSar-NPs are a promising drug delivery system for the treatment of HCC, and further research is needed to investigate their potential in clinical treatment.

Inhibitory effect of licorice extract on the germination and outgrowth of Paraclostridium bifermentans spores

INTRODUCTION

Paraclostridium bifermentans is responsible for spoilage properties in vacuum-packaged meat. Ordinary heat treatment techniques are ineffective to control the extremely heat-resistant spores of P. bifermentans. Therefore, finding a new strategy to prevent the contamination of P. bifermentans spores in vacuum-packaged meat is challenging.

METHODS

In this study, P. bifermentans was isolated from the vacuum-packaged chicken, and the inhibitory effects of licorice extract on the germination and outgrowth of P. bifermentans spores, as well as the key bioactive components in the licorice extract involved in inhibiting spore activity, were investigated.

RESULTS

The spores induced by combination-nutrient-germinant (150 mmol/L L-alanine and 20 mmol/L inosine, co-AI) did not germinate when the concentration of licorice extract was ≥ 3.13 mg/ml. The germination of P. bifermentans spores induced by non-nutrient-germinant (8 mmol/L dipicolinic acid, DPA) was completely prevented by licorice extract at least 1.56 mg/ml. While the outgrowth of P. bifermentans spores was inhibited at a concentration of 0.39 mg/ml. Licorice extract did not seem to damage the non-germinated spores but blocked the germinant sensing. Licorice extract prevented the outgrowing spores from becoming vegetable cells by disrupting the inner membrane. Furthermore, the results obtained from LC-MS data analysis exhibited 15 key bioactive compounds in licorice extract, such as glycyrrhizic acid, liquiritin, etc. Among them, glycyrrhizic acid and liquiritin apioside exerted efficient inhibitory properties on the germination and outgrowth of P. bifermentans spores.

DISCUSSION

This present study demonstrated that licorice extract can be used as a promising inhibitor of spores and provides a new method to control the residual P. bifermentans spores in meat products. Meanwhile, this study exhibits a baseline for the better understanding of the potential application of licorice extracts to control the P. bifermentans spores in meat products.

Selenophene-Modified Boron Dipyrromethene-Based Photosensitizers Exhibit Photodynamic Inhibition on a Broad Range of Bacteria

Microorganisms are crucial for human survival in view of both mutualistic and pathogen interactions. The control of the balance could be achieved by use of the antibiotics. There is a continuous arms race that exists between the pathogen and the antibiotics. The emergence of multidrug-resistant (MDR) bacteria threatens health even for insignificant injuries. However, the discovery of new antibiotics is not a fast process, and the healthcare system will suffer if the evolution of MDR lingers in its current frequency. The cationic photosensitizers (PSs) provide a unique approach to develop novel, light-inducible antimicrobial drugs. Here, we examine the antimicrobial activity of innovative selenophene-modified boron dipyrromethene (BODIPY)-based PSs on a variety of Gram (+) and Gram (-) bacteria. The candidates demonstrate a level of confidence in both light-dependent and independent inhibition of bacterial growth. Among them, selenophene conjugated PS candidates (BOD-Se and BOD-Se-I) are promising agents to induce photodynamic inhibition (PDI) on all experimented bacteria: E. coli, S. aureus, B. cereus, and P. aeruginosa. Further characterizations revealed that photocleavage ability on DNA molecules could be potentially advantageous over extracellular DNA possessing biofilm-forming bacteria such as B. cereus and P. aeruginosa. Microscopy analysis with fluorescent BOD-H confirmed the colocalization on GFP expressing E. coli.

Tetrazolium-Based Visually Indicating Bacteria Sensor for Colorimetric Detection of Point of Contamination

Protective equipment for detecting bacterial contamination has been in high demand with increasing interest in public health and hygiene. Herein, a fiber-based visually indicating bacteria sensor (VIBS) embedded with iodonitrotetrazolium chloride is developed for the general purpose of detecting live bacteria, and its chromogenic effectiveness is investigated for Gram-negative Escherichia coli and Gram-positive Micrococcus luteus. The developed color intensity is measured by the light absorption coefficient to the scattering coefficient (K/S) based on the Kubelka-Munk equation, and the colorimetric sensitivities of different membranes are examined by calculating the limit of detection (LOD) and the limit of quantification (LOQ). The results demonstrate that the interactions between VIBS and bacteria depend on the wetting properties of membranes. A hydrophobic membrane shows excessive interactions at high concentrations of Gram-negative E. coli bacteria, whose cell membrane is lipophilic. The membrane blended with hydrophobic and hydrophilic polymers displays linear colorimetric responses for both Gram-negative and Gram-positive bacteria strains, demonstrating a reliable sensing capability in the range of the tested bacteria concentration. This study is significant in that explorative experimentations are performed to conceive a proof of concept of a fiber-based bacteria sensor, which is readily applicable in various fields where bacteria pose a threat.

Synthesis of smart carriers based on tryptophan-functionalized magnetic nanoparticles and its application in 5- Fluorouracil delivery

Multifunctional nanocarriers, specifically for tumor targeting and traceable features, have been increasingly considered in cancer therapies. Herein, a novel targeting agent (TA), tryptophan(TRP), was proposed for the synthesis of functionalized APTES-iron oxide nanoparticles using two methods, creating a smart drug delivery system (DDS). In one method, two-step, glutaraldehyde (GA) as a linker, bonded TRP and amino-functionalized magnetite (AMFM), and in the second method, one step, TRP binding was carried out by (3-dimethyl aminopropyl)-N'-ethyl carbodiimide hydrochloride (EDC)/ N-hydroxysuccinimide ester (NHS). The synthesis yield of the second method was 7% higher than the first method. After synthesizing DDS, 5-Fluorouracil (5-FU) was loaded on nanocarriers and was observed that TRP functionalized nanoparticles by GA have better loading efficiency, which was 50% greater than the product from the one-step method. A pH-sensitive release profile was also studied for 5-FU/DDS with the release of almost 75% and 50% at pH 5.5 and 7.4, respectively. To analyze the biological aspects of nanocarriers, human breast cancer, MCF-7, and embryonic kidney, HEK293, cell lines were used for cellular uptake and MTT assays. In-vitro studies confirmed that TRP can act as a TA as its cellular uptake through cancerous cells was 40% greater than normal cells, and the MTT assay confirmed that using DDS can increase and decrease the cell viability of normal cells and cancerous cells, respectively, compared to free drug. Therefore, it was concluded that advanced nano-assembly is a great candidate for breast cancer cell-targeted delivery.

Development of a Tetrazolium-Derived Paper-Based Diagnostic Device as an Early, Alternative Bacteria Screening Tool

(1) Background: The complexity, amount of time, and the large amount of resource required to perform gold-standard bacteria culture procedures makes it difficult to perform timely pathogenic analyses, especially in areas where such resources are not readily available. A paper-based biochemical analytical tool can potentially tackle problems economically in terms of time and convenience, potentially finding utility in applications where simple and timely detection of bacteria is necessary; (2) Methods: The utility of paper-based MTT-PMS strips was tested using a simple colorimetric analytical methodology; (3) Results: Sufficient evidence was obtained to suggest that the strips can potentially be used as a rapid and convenient early, alternative bacteria screening tool for a variety of applications; (4) Conclusions: The potential of strips for the rapid detection of bacteria compared to standard bacteria culture is a key advantage in certain clinical, agricultural, and environmental applications.

Improved Formazan Dissolution for Bacterial MTT Assay

The MTT assay, based on the enzymatic reduction of the water-soluble, yellowish tetrazolium salt 3-(4,5-dimethylthiazol)-2,5-diphenyl-tetrazolium bromide (MTT) to purple formazan, is commonly used for assessment of cell viability and proliferation. Accurate performance by the MTT assay depends on complete solubilization of cells and formazan and stability of the colored solution. Comparison of different solubilization solutions revealed that dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), buffered with ammonia buffer, pH 10, and containing 5% SDS, produced the best results. These two solvents provided rapid and complete solubilization of formazan and cells, with minimal background absorbance at 700 nm, good reproducibility (low interassay coefficient of variation), high sensitivity, and color stability for at least 24 h. A linear relationship between viable-cell number and formazan absorbance was preserved for cell densities up to ∼1 × 10⁹ cells/mL for Gram-negative and Gram-positive microorganisms. Since MTT can be reduced by medium components in the absence of cells, blanks containing all medium components but no cells should be run simultaneously. Measurements at two wavelengths, one corresponding to absorption peak of formazan (570 nm) and a background absorbance far from the peak (700 nm), are necessary to avoid artifacts due to incomplete solubilization and turbidity.

IMPORTANCE Reduction of the water-soluble tetrazolium salt 3-(4,5-dimethylthiazol)-2,5 diphenyl-tetrazolium bromide (MTT) to purple, water-insoluble formazan is commonly used for assessment of cell viability and proliferation. Spectrophotometric detection of formazan requires its solubilization. The solubilization solvent has a strong influence on data acquisition and often introduces artifacts, leading to misreading of results. This study offers a choice of solvents that minimize solubilization artifacts when the MTT test is applied to microbiological cultures.