Use of Aloe Vera Gel as Media to Assess Antimicrobial Activity and Development of Antimicrobial Nanocomposites.

Antimicrobial resistance is a menace to public health on a global scale. In this regard, nanomaterials exhibiting antimicrobial properties represent a promising solution. Both metal and metal oxide nanomaterials are suitable candidates, even though their mechanisms of action vary. Multiple antimicrobial mechanisms can occur simultaneously or independently; this includes either direct contact with the pathogens, nanomaterial uptake, oxidative stress, ion release, or any of their combinations. However, due to their specific properties and more particularly fast settling, existing methods to study the antimicrobial properties of nanoparticles have not been specifically adapted in some cases. The development of methodologies that can assess the antimicrobial properties of metallic nanomaterials accurately is necessary. A cost-effective methodology with a straightforward set-up that enables the easy and quick assessment of the antimicrobial properties of metal nanoparticles with high accuracy has been developed. The methodology is also capable of confirming whether the killing mechanism involves ionic diffusion. Finally, Aloe Vera gel showed good properties for use as a medium for the development of antimicrobial ointment.

Switching to nanonutrients for sustaining agroecosystems and environment: the challenges and benefits in moving up from ionic to particle feeding.

The worldwide agricultural enterprise is facing immense pressure to intensify to feed the world's increasing population while the resources are dwindling. Fertilizers which are deemed as indispensable inputs for food, fodder, and fuel production now also represent the dark side of the intensive food production system. With most crop production systems focused on increasing the quantity of produce, indiscriminate use of fertilizers has created havoc for the environment and damaged the fiber of the biogeosphere. Deteriorated nutritional quality of food and contribution to impaired ecosystem services are the major limiting factors in the further growth of the fertilizer sector. Nanotechnology in agriculture has come up as a better and seemingly sustainable solution to meet production targets as well as maintaining the environmental quality by use of less quantity of raw materials and active ingredients, increased nutrient use-efficiency by plants, and decreased environmental losses of nutrients. However, the use of nanofertilizers has so far been limited largely to controlled environments of laboratories, greenhouses, and institutional research experiments; production and availability on large scale are still lagging yet catching up fast. Despite perceivable advantages, the use of nanofertilizers is many times debated for adoption at a large scale. The scenario is gradually changing, worldwide, towards the use of nanofertilizers, especially macronutrients like nitrogen (e.g. market release of nano-urea to replace conventional urea in South Asia), to arrest environmental degradation and uphold vital ecosystem services which are in critical condition. This review offers a discussion on the purpose with which the nanofertilizers took shape, the benefits which can be achieved, and the challenges which nanofertilizers face for further development and real-world use, substantiated with the significant pieces of scientific evidence available so far.

Photo-responsive polymeric nanocarriers for target-specific and controlled drug delivery.

Conventional drug delivery systems often have several pharmacodynamic and pharmacokinetic limitations related to their low efficacy and bad safety. It is because these traditional systems cannot always be selectively addressed to their therapeutic target sites. Currently, target-specific and controlled drug delivery is one of the foremost challenges in the biomedical field. In this context, stimuli-responsive polymeric nanomaterials have been recognized as a topic of intense research. They have gained immense attention in therapeutics - particularly in the drug delivery area - due to the ease of tailorable behavior in response to the surroundings. Light irradiation is of particular interest among externally triggered stimuli because it may be specifically localized in a contact-free manner. Light-human body interactions may sometimes be harmful due to photothermal and photomechanical reactions that lead to cell death by photo-toxicity and/or photosensitization. However, these limitations may also be overcome by the use of photo-responsive polymeric nanostructures. This review summarizes recent developments in photo-responsive polymeric nanocarriers used in the field of drug delivery systems, including nanoparticles, nanogels, micelles, nanofibers, dendrimers, and polymersomes, as well as their classification and mechanisms of drug release.

A meta analysis for evaluation of marginal bone level changes at dental implants.

AIM: The aim of this study was to assess the marginal bone level changes at dental implants after 1 year in function. METHODS: Detailed searches from PubMed databases were made. A MEDLINE search (PubMed) published in the English language from 1980 to December 2018 was included in this study. RESULTS: The electronic database research (MEDLINE) produced 166 corresponding articles. One hundred and twenty studies were excluded on the basis of abstract while the 46 researches were used chosen for full-text examination after the title and abstract testing, and 41 studies were excluded that did not meet the requirements of our inclusion and exclusion criteria. A total of 5 studies for a quantitative analysis were taken into account. CONCLUSION: Within the limits of the study, the mean marginal bone loss (MBL) was found to be 0.56 mm. A statistically significant difference in the MBL was found between the various studies.

Aryldiazoquinoline based multifunctional small molecules for modulating Aß42 aggregation and cholinesterase activity related to Alzheimer's disease.

Research continues to find a breakthrough for the treatment of Alzheimer's Disease (AD) due to its complicated pathology. Presented herein is a novel series of arydiazoquinoline molecules investigated for their multifunctional properties against the factors contributing to Alzheimer's disease (AD). The inhibitory properties of fourteen closely related aryldiazoquinoline derivatives have been evaluated for their inhibitory effect on Aß42 peptide aggregation. Most of these molecules inhibited Aß42 fibrillation by 50-80%. Selected molecules were also investigated for their binding behaviour to preformed Aß40 aggregates indicating a nanomolar affinity. In addition, these compounds were further investigated as cholinesterase inhibitors. Interestingly, some of the compounds turned out to be moderate in vitro inhibitors for AChE activity with IC50 values in low micro molar range. The highest anti-AChE activity was shown by compound labelled as 2a with an IC50 value of 6.2 µM followed by 2b with IC50 value of 7.0 µM. In order to understand the inhibitory effect, binding of selected molecules to AChE enzyme was studied using molecular docking. In addition, cell toxicity studies using Neuro2a cells were performed to assess their effect on neuronal cell viability which suggests that these molecules possess a non-toxic molecular framework. Overall, the study identifies a family of molecules that show good in vitro anti-Aß-aggregation properties and moderately inhibit cholinesterase activity.

Evaluation of osseintegration between traditional and modified hydrophilic titanium dental implants - Systematic analysis.

The aim of the study was to conduct a systematic review to access the osseointegration between traditional and modified Hydrophilic Titanium Dental Implants for period of 10 years. PUBMed articles were searched from last ten years up to 15/12/2019 from which 24 studies included in this review. This systematic review compiles the data about osseintegration in hydrophilic titanium implants in human trials. It sheds light on the mechanism of integration of hydrophilic surfaces and numeric data to support the purpose of the review.

A comparative evaluation of immediate versus delayed loading of two implants with mandibular overdenture: An in vivo study.

INTRODUCTION: Implant-supported overdenture has been a common treatment for edentulous patients for the past several years and predictably achieves good clinical results, especially in those patients who were uncomfortable with their conventional dentures, as they provide additional retention and support. The concept of immediate loading is more applicable to completely edentulous patients because of their functional and esthetic requirements. Hence, the present study aims to evaluate the outcomes of immediate loading of mandibular two-implant-retained overdenture and compare it with the conventional delayed loading concept. METHOD: This in vivo study was conducted to compare immediate versus delayed loading of two implants with mandibular overdenture. A total of 20 completely edentulous patients (10 delayed loading and 10 immediate loading) were included in the study and certain parameters, i.e., bone loss around implants, periodontal pocket depth, pain and discomfort, implant stability, and microflora around implants, were measured immediately and after healing period of 3 and 6 months. RESULT: It can be analyzed from the observations that patients were more satisfied with delayed loading in terms of comfort, speech, function, pain, and chewing efficiency as compared to immediate loading. CONCLUSION: It is concluded that implants loaded under delayed protocol seem to have a higher success rate as compared to those that are loaded immediately.

Versatile biomedical potential of biosynthesized silver nanoparticles from Acacia nilotica bark.

The present study reports the development of potent silver nanoparticles (AgNPs) using bark extract of Acacia nilotica and evaluation of its wound healing, anti-biofilm, anti-cancer and anti-microbial activity. Stable, small sized nanoparticles with spherical morphology were obtained after significant optimization studies that was evaluated through UV-visible spectroscopy. Thereafter, physicochemical characterization of biosynthesized AgNPs was carried out through DLS and FESEM for evaluation of size. EDAX and FTIR were carried out for the evaluation of composition and possible functional groups involved in the reduction and capping of AgNPs. The antibacterial potential was investigated through disc diffusion assay against Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa). Further, the Congo Red Assay (CRA) successfully revealed the anti-biofilm activity against Bacillus subtilis (B. subtilis), Staphylococcus aureus (S. aureus), Proteus vulgaris (P. vulgaris), Pseudomonas aeruginosa (P. aeruginosa). Alamar blue assay was conducted in A549 cells to reveal the remarkable anticancer activity of biosynthesized AgNPs that resulted in a very appreciable manner. Further, the wound healing activity of AgNPs can heal the excised wound of mice up-to 100% within 15 days. All these studies suggested that our biosynthesized AgNPs possess versatile biomedical application.

Evaluation of Anticancer activity of Silver Nanoparticles on the A549 Human lung carcinoma cell lines through Alamar Blue Assay.

Silver nanoparticles have been widely studied to possess antimicrobial as well as anticancer activity, and have found its applications in various fields including pharmaceutical industry, diagnostics, drug delivery, food industry, and others. For this purpose, several cell proliferation assays are widely used for the evaluation of anticancer activity of synthetic compounds as well as natural plant extracts. In general, a compound is said to possess an anticancer activity if it prevents the cancer cells to grow and divide actively, and indirectly activates the generic program of cell death. In this protocol, Alamar blue and MTT assay are described for the analysis of metabolic function and health of the cell. These procedures are generally used for the endpoint analysis. A549 cells are seeded in a 96-well plate, and after the adherence of the cells, they are treated with different concentrations of silver nanoparticles. Followed by 24 h of incubation, colorimetric dyes are added to the wells, and the absorbance is recorded to quantify the percentage cytotoxicity in the sample wells.

Catalytic, antibacterial and antibiofilm efficacy of biosynthesised silver nanoparticles using Prosopis juliflora leaf extract along with their wound healing potential.

The present study focuses on the catalytic, antibacterial and antibiofilm efficacy of silver nanoparticles (AgNPs) in an easy, rapid and eco-friendly pathway. Herein, we have synthesised AgNPs using an aqueous extract of P. juliflora leaf. The bioactive compounds present in the extract are responsible for the reduction of Ag+ to Ag0. The particle synthesis was first observed by visual color change and then characterized using UV-visible spectroscopy to confirm the formation of AgNPs. The synthesis conditions were then optimised using critical parameters such as reaction time, AgNO3 concentration, extract to AgNO3 ratio and temperature of the reaction. The hydrodynamic size of the AgNPs with Dynamic light scattering (DLS) was 55.24 nm, while, was in the range of 10-20 nm as determined through Transmission Electron Microscopy (TEM). Further, Fourier transform infrared spectroscopy (FTIR) studies were conducted to discern the functional groups or compounds responsible for the reduction of silver nitrate as well as the capping of silver nanoparticles. Later, X-ray diffraction (XRD) results showed crystalline nature of the biosynthesized AgNPs. To evaluate their antibacterial potential, AgNPs were assessed through disc-diffusion assay, which resulted in an appreciable dose-dependent activity. The antibacterial potential was investigated through disc-diffusion assay against E. coli and P. aeruginosa. The Congo red agar (CRA) plate assay successfully revealed the anti-biofilm activity against B. subtilis and P. aeruginosa. Further, the catalytic activity of synthesised AgNPs was assessed against azo dyes such a Methylene Blue (MB) and Congo Red (CR) that resulted in its effective degradation of toxic compounds in a short span of time. Further, AgNPs were assessed for their wound healing potential.

Bile Acid Oligomers and Their Combination with Antibiotics To Combat Bacterial Infections.

The ever-growing risk of bacterial resistance is a critical concern. Among the various antimicrobial resistant bacterial strains, methicillin and vancomycin resistant Staphylococcus aureus are among the most dreadful, causing serious complications. On the basis of the hypothesis that microbes have reduced ability to develop resistance against membrane targeting antibiotics, bile acid oligomers having unique facially amphiphilic topologies were designed and synthesized. The oligomers with specific linkers exhibited potent and selective antibacterial activity against Gram-positive bacteria. The lead compounds also improved the efficacy of a range of known antibiotics belonging to different classes when tested in combination. The active dimers were found to be effective against antibiotic-resistant clinical isolates of S. aureus, including multidrug resistant isolates. A significant inhibitory activity against S. aureus biofilm, a highly drug-resistant bacterial phenotype often unresponsive to antibiotic therapy, was also noticed. No adverse effects were observed by these dimers in a cell viability assay against HEK293 cells.

Hypochlorite-Mediated Modulation of Photoinduced Electron Transfer in a Phenothiazine-Boron dipyrromethene Electron Donor-Acceptor Dyad: A Highly Water Soluble "Turn-On" Fluorescent Probe for Hypochlorite.

A highly water-soluble phenothiazine (PTZ)-boron dipyrromethene (BODIPY)-based electron donor-acceptor dyad (WS-Probe), which contains BODIPY as the signaling antennae and PTZ as the OCl- reactive group, was designed and used as a fluorescent chemosensor for the detection of OCl- . Upon addition of incremental amounts of NaOCl, the quenched fluorescence of WS-Probe was enhanced drastically, which indicated the inhibition of reductive photoinduced electron transfer (PET) from PTZ to 1 BODIPY*; the detection limit was calculated to be 26.7 nm. Selectivity studies with various reactive oxygen species, cations, and anions revealed that WS-Probe was able to detect OCl- selectively. Steady-state fluorescence studies performed at varied pH suggested that WS-Probe can detect NaOCl and exhibits maximum fluorescence in the pH range of 7 to 8, similar to physiological conditions. ESI-MS analysis and 1 H NMR spectroscopy titrations showed the formation of sulfoxide as the major oxidized product upon addition of hypochlorite. More interestingly, when WS-Probe was treated with real water samples, the fluorescence response was clearly visible with tap water and disinfectant, which indicated the presence of OCl- in these samples. The in vitro cell viability assay performed with human embryonic kidney 293 (HEK 293) cells suggested that WS-probe is non-toxic up to 10 µm and implicates the use of the probe for biological applications.

Green synthesis of silver nanoparticles using Prosopis juliflora bark extract: reaction optimization, antimicrobial and catalytic activities.

In the present study, silver nanoparticles (PJB-AgNPs) have been biosynthesized employing Prosopis juliflora bark extract. The biosynthesis of silver nanoparticles was monitored on UV-vis spectrophotometer. The size, charge and polydispersity index (PDI) of PJB-AgNPs were determined using dynamic light scattering (DLS). Different parameters dictating the size of PJB-AgNPs were explored. Nanoparticles biosynthesis optimization studies suggested efficient synthesis of highly dispersed PJB-AgNPs at 25 °C when 9.5 ml of 1 mM AgNO3 was reduced with 0.5 ml of bark extract for 40 min. Characterization of PJB-AgNPs by SEM showed spherical-shaped nanoparticles with a size range ∼10-50 nm along with a hydrodynamic diameter of ∼55 nm as evaluated by DLS. Further, characterizations were done by FTIR and EDS to evaluate the functional groups and purity of PJB-AgNPs. The antibacterial potential of PJB-AgNPs was tested against E. coli and P. aeruginosa. The PJB-AgNPs remarkably exhibited anticancer activity against A549 cell line as evidenced by Alamar blue assay. The dye degradation activity was also evaluated against 4-nitrophenol that has carcinogenic effect. The results thus obtained suggest application of PJB-AgNPs as antimicrobial, anticancer and catalytic agents.

Degradation of anthropogenic pollutant and organic dyes by biosynthesized silver nano-catalyst from Cicer arietinum leaves.

The work represents the potent catalytic activity of silver nanoparticles synthesized from Cicer arietinum (chickpea) leaf extract (CAL-AgNPs). Here, silver nano-catalysts were used against the anthropogenic pollutants mainly involving nitro-amines and azo dyes. These pollutants are extremely harmful to our environment and causes severe health issues. The CAL-AgNPs have the potential to degrade harmful toxins and their by-products, thereby decreasing the pollutants from the environment. The green synthesis of nano-catalyst includes a simple, cost effective and eco-friendly method using the leaf extract from the plant. A systematic study was conducted, including synthesis, optimization and characterization of the silver particles. The AgNPs were further assessed through DLS and TEM for size and morphological evaluation. The obtained particles have shown spherical morphology with the size range of 88.8nm. Further, FTIR were performed for compositional and functional group analysis of the particles. The antibacterial efficiency was also evaluated against E. coli and P. aeruginosa. For their catalytic evaluation, CAL-AgNPs were assessed for 4-nitrophenol, methylene blue and congo red. The results obtained through catalytic evaluation suggested that the CAL-AgNPs could be helpful to surmount the environmental pollution in a very effective manner.

Antibacterial potential of silver nanoparticles biosynthesised using Canarium ovatum leaves extract.

Silver nanoparticles (AgNPs) have been extensively used as antibacterial agents, owing to their ease of preparation. In the present study, leaves extract of Canarium ovatum have been employed for the biosynthesis of silver nanoparticles (CO-AgNPs). CO-AgNPs were synthesised under very mild, eco-friendly manner where the plant extract acted both as reducing and capping agent. These AgNPs were synthesised by taking into account several parameters, that included, time of reaction, concentration of AgNO3, amount of extract and temperature of reaction. The optimisation studies suggested efficient synthesis of CO-AgNPs at 25°C when 1.5 mM AgNO3 was reduced with 1:20 ratio of plant extract for 40 min. Size determination studies done on dynamic light scattering and scanning electron microscope suggested of spherical shape nanoparticles of size 119.7 ± 7 nm and 50-80 nm, respectively. Further, characterisations were done by Fourier transform infrared and energy-dispersive X-ray spectroscopy to evaluate the functional groups and the purity of CO-AgNPs. The antibacterial efficacy of CO-AgNPs was determined against the bacterial strain Pseudomonas aeruginosa. As evident from disc diffusion method studies, CO-AgNPs remarkably inhibited the growth of the tested microorganism. This study suggested that C. ovatum extract efficiently synthesises CO-AgNPs with significant antibacterial properties and can be good candidates for therapeutics.

Effect of size on biological properties of nanoparticles employed in gene delivery.

CONTEXT: The size of nanoparticles plays a pivotal role in determining the gene delivery efficiency. OBJECTIVE: A focus on the studies done to investigate the effect of nanoparticles size on biological aspects of gene delivery. METHODS: A through literature survey has been done regarding studies done to investigate the effect of nanoparticles size on uptake, transfection efficiency and biodistribution has been cited in the present review. RESULTS AND CONCLUSION: The gene delivery efficacy may depend on conjugation of several factors such as the chemical structure of polymers, cell type, and nanoparticle size, composition and interaction with cells.