Despite numerous existing potent antibiotics and other antimicrobial means, bacterial infections are still a major cause of morbidity and mortality. Moreover, the need to develop additional bactericidal means has significantly increased due to the growing concern regarding multidrug-resistant bacterial strains and biofilm associated infections. Consequently, attention has been especially devoted to new and emerging nanoparticle-based materials in the field of antimicrobial chemotherapy. The present review discusses the activities of nanoparticles as an antimicrobial means, their mode of action, nanoparticle effect on drug-resistant bacteria, and the risks attendant on their use as antibacterial agents. Factors contributing to nanoparticle performance in the clinical setting, their unique properties, and mechanism of action as antibacterial agents are discussed in detail.

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Alternative Antimicrobial Approach: Nano-Antimicrobial Materials

Author(s): Chen, Fanqing; Gerion, Daniele | Abstract: One of the biggest challenges in cell biology is the imaging of living cells. For this purpose, the most commonly used visualization tool is fluorescent markers. However, conventional labels, such as organic fluorescent dyes or green fluorescent proteins (GFP), lack the photostability to allow the tracking of cellular events that happen over minutes to days. In addition, they are either toxic to cells (dyes), or difficult to construct and manipulate (GFP). We report here the use of a new class of fluorescent labels, silanized CdSe/ZnS nanocrystal-peptide conjugates, for imaging the nuclei of living cells. CdSe/ZnS nanocrystals, or so called quantum dots (qdots), are extremely photostable, and have been used extensively in cellular imaging of fixed cells. However, most of the studies about living cells so far have been concerned only with particle entry into the cytoplasm or the localization of receptors on the cell membrane. Specific targeting of qdots to the nucleus of living cells has not been reported in previous studies, due to the lack of a targeting mechanism and proper particle size. Here we demonstrate for the first time the construction of a CdSe/ZnS nanocrystal-peptide conjugate that carries the SV40 large T antigen nuclear localization signal (NLS), and the transfection of the complex into living cells. By a novel adaptation of commonly used cell transfection techniques for qdots, we were able to introduce and retain the NLS-qdots conjugate in living cells for up to a week without detectable negative cellular effects. Moreover, we can visualize the movement of the CdSe/ZnS nanocrystal-peptide conjugates from cytoplasm to the nucleus, and the accumulation of the complex in the cell nucleus, over a long observation time period. This report opens the door for using qdots to visualize long-term biological events that happen in the cell nucleus, and provides a new nontoxic, long-term imaging platform for cell nuclear processes.

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Fluorescent CdSe/ZnS nanocrystal-peptide conjugates for long-term, nontoxic imaging and

Classically all vaccines were produced using live or attenuated microorganisms or parts of them. However, the use of whole organisms, their components or the biological process for vaccine production has several weaknesses. The presence of immunologically redundant biological components or biological impurities in such vaccines might cause major problems. All the disadvantageous of traditional vaccines might be overcome via the development of fully synthetic peptide-based vaccines. However, once minimal antigenic epitopes only are applied for immunisation, the immune responses are poor. The use of an adjuvant can overcome this obstacle; however, it may raise new glitches. Here we briefly summarise the current stand on peptide-based vaccines, discuss epitope and adjuvant design, and multi-epitope and nanoparticle-based vaccine approaches. This mini review discusses also the disadvantages and benefits associated with peptide-based vaccines. It proposes possible methods to overcome the weaknesses of the synthetic vaccine strategy and suggests future directions for its development.

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Peptide-based synthetic vaccines

The era of antibiotic resistance is a cause of increasing concern as bacteria continue to develop adaptive countermeasures against current antibiotics at an alarming rate In recent years, studies have reported nanoparticles as a promising alternative to antibacterial reagents because of their exhibited antibacterial activity in several biomedical applications, including drug and gene delivery, tissue engineering, and imaging Moreover, nanomaterial research has led to reports of a possible relationship between the morphological characteristics of a nanomaterial and the magnitude of its delivered toxicity However, conventional synthesis of nanoparticles requires harsh chemicals and costly energy consumption Additionally, the exact relationship between toxicity and morphology of nanomaterials has not been well established Here, we review the recent advancements in synthesis techniques for silver, gold, copper, titanium, zinc oxide, and magnesium oxide nanomaterials and composites, with a focus on the toxicity exhibited by nanomaterials of multidimensions This article highlights the benefits of selecting each material or metal-based composite for certain applications while also addressing possible setbacks and the toxic effects of the nanomaterials on the environment

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Antibacterial properties and toxicity from metallic nanomaterials.

Effect of metal and metal oxide nanoparticles on growth and physiology of globally important food crops: A critical review

Nanotechnology has emerged as one of the leading fields of the science having tremendous application in diverse disciplines. As nanomaterials are increasingly becoming part of everyday consumer products, it is imperative to assess their impact on living organisms and on the environment. Physicochemical characteristics of nanoparticles and engineered nanomaterials including size, shape, chemical composition, physiochemical stability, crystal structure, surface area, surface energy, and surface roughness generally influence the toxic manifestations of these nanomaterials. This compels the research fraternity to evaluate the role of these properties in determining associated toxicity issues. Reckoning with this fact, in this paper, issues pertaining to the physicochemical properties of nanomaterials as it relates to the toxicity of the nanomaterials are discussed.

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Physicochemical properties of nanomaterials: implication in associated toxic manifestations

It is estimated that the global prevalence of dementia will rise as high as 24 million and predicted to be double in every 20 years which is attributed to the fact that the ageing population is increasing and so more individuals are at risk of developing neurodegenerative diseases like Alzheimer’s. Many scientists favored glycation of proteins such as tau, amyloid beta (Aβ) etc. as one of the important risk factor in Alzheimer’s disease (AD). Since, d-ribose shows highest glycation ability among other sugars hence, produces advanced glycation end products (AGEs) rapidly. However, there are several other mechanisms suggested by researchers through which d-ribose may cause cognitive impairments. There is a concern related to diabetic patients since they also suffer from d-ribose metabolism, may be more prone to AD risk. Thus, it is imperative that the pathogenesis and the pathways involved in AD progression are explored in the light of ribosylation and AGEs formation for identifying suitable diagnostics marker for early diagnosis or finding promising therapeutic outcomes.

d -ribose and pathogenesis of Alzheimer’s disease

Context: The global scenario of illness is shifting from infectious diseases to non-communicable diseases, with chronic conditions such as heart diseases, stroke and Chronic Obstructive Pulmonary Disease (COPD) now being chief causes of death globally and more than 90% of deaths due to COPD occur in low and midline income countries.[1] Low serum vitamin D level is associated with various lung diseases and decreased lung function.[2] Aims: This study was designed to study the serum vitamin D level and its correlation with severity of COPD as assessed by spirometry, COPD assessment test (CAT) and exercise capacity and BMI of COPD patients. Settings and Design: Observational cross sectional study conducted on patients of COPD attending the outpatient department. Materials and Methods: One hundred sixty consecutive patients of COPD attending the outpatient Department were included in the study. Pack years, CAT score, 6 minute walk distance, post bronchodilator spirometry values and BMI was recorded along with complete history and physical examination. Statistical Analysis Used: Data analysis was done using IBM SPSS 23 software. Descriptive statistics, Independent sample t test, ANOVA and Pearson correlation were applied. Results: A significant positive correlation was found between FeV1% of predicted and serum Vitamin D level(r = 0.291; P

Correlation of severity of chronic obstructive pulmonary disease with serum vitamin-D level

Context: India has 18% of the global population and an increasing burden of chronic respiratory diseases. The prevalence of Metabolic syndrome (MS) was found to be as high as 39.7% among Indian population. Metabolic syndrome is found to be more common in Chronic Obstructive Pulmonary Disease (COPD) when compared to the general population. This study was done to assess the prevalence of metabolic syndrome in COPD and the association of systemic inflammation in COPD patients with metabolic syndrome. Methodology: This study enrolled 150 consecutive consenting patients of stable COPD attending the outpatient pulmonology department. Detailed history, clinical examination, spirometry, and relevant routine laboratory investigations including complete blood count, fasting blood sugar, and lipid profile were done. In addition, hsCRP, Serum lactate and Vitamin D level was assessed in all patients. Diagnosis of COPD and Metabolic syndrome was done according to GOLD guidelines, 2018 and the International Diabetes Federation criteria respectively. Result: The prevalence of metabolic syndrome was found to be 27.3% in our COPD patients. The frequency of metabolic syndrome in GOLD stage I, II, III, and IV was 75%, 32%, 17%, and 13.5%, respectively. Logistic regression analysis showed a significant relationship of blood leucocyte count (OR = 0.342, CI = 0.171-0.686), hs-CRP (OR = 0.020, CI = 0.003-0.122), pack years (OR = 1.083, CI = 1.026-1.14) and vitamin D levels (OR = 1.219, CI = 1.093-1.359) with metabolic syndrome in COPD patients. Conclusion: Metabolic syndrome is a co-morbidity that is very often overlooked in patients of COPD. Systemic inflammation which is a common characteristic of both COPD and Metabolic syndrome has been found to be an important contributor towards cardiovascular morbidity and mortality.

Systemic inflammation in patients of chronic obstructive pulmonary disease with metabolic syndrome.

In the present scenario, the burgeoning field of nanotechnology is playing central role in various real world applications. Researches engrossing nanoparticles are evolving at a rapid pace owing to which engineered nanomaterials are increasingly becoming part of daily life in the form of cosmetics, food packaging, drug delivery, therapeutics, biosensors, etc. It is intrigued that the properties of nanoparticles which bestow them their unique physicochemical characteristics could also lead to adverse biological consequences such as increased uptake and interaction with the biological systems. Nanomaterials, due to their small size could enter the body through various semi open anatomical interfaces and can penetrate through cells and organelles and disrupt their normal function, which could lead to tissue inflammation, altered cellular redox balance or even cell death. Nanoparticles unlike larger particles can transverse through the circulatory/lymphatic to various vital organs of the body including nervous systems and brain. Nanomaterials could lead to various allied illnesses including bronchitis, asthma, lung and liver cancer, Parkinson’s disease, Alzheimer’s disease, Crohn’s disease, heart disease and colon cancer. Reckoning with the unprecedented applicability’s of nanomaterials in daily life, avenues for direct or indirect exposures of nanoparticles to human beings increases, which raises concern about their role in vivo toxicity. This necessitates intensive research to have knowledge of the various routes of nanoparticle exposure and their effects upon the human health. This review is an attempt to evaluate the various modes of exposure of nanoparticles in human beings, mechanism of toxicity, their fate inside body and adverse health effects.

Sufia Naseem

Papers

Physicochemical properties of nanomaterials: implication in associated toxic manifestations

d -ribose and pathogenesis of Alzheimer’s disease

Correlation of severity of chronic obstructive pulmonary disease with serum vitamin-D level

Systemic inflammation in patients of chronic obstructive pulmonary disease with metabolic syndrome.

In vivo toxicity of nanoparticles: modalities and treatment