Spectroscopic characterization and antimicrobial activity of nanoparticle doped cyclodextrin polyurethane bionanosponge

The effect of TiO2 nanoparticles on bacterial growth: the effect of particle size and their structure - a systematic review

One of the widely used microbiological methods to determine the toxicity of chemicals, catalysts, and other types of materials is the minimum inhibitory concentration (MIC) test. The present study aims to investigate the influence of composition of composite materials based on TiO2 and their particle size as well as bacterial type and shape based on the MIC values reported in the literature. The results show that among the 36 articles selected, most of the studies used Escherichia coli (E. coli) (26) and Staphylococcus aureus (S. aureus) (19) bacteria to determine MIC values. This study revealed that the MIC in values below 70 µg ml-1 for S. aureus was lower than that for E. coli bacteria (below 200 µg ml-1). Importantly, MIC value decreased from 60.6 to 7.66 µg ml-1 with decrease in the size of nanoparticles. It follows from the increased surface area for smaller-sized particles, thus increased interaction with bacteria during MIC test.

Fabrication of Low-Temperature Fast Gelation β-Cyclodextrin-Based Hydrogel-Loaded Medicine for Wound Dressings

β-Cyclodextrin (β-CD) is often used as a drug carrier for biomedical materials due to its unique cavity structure. Herein, β-CD was modified by acryloyl chloride and further copolymerized with N-isopropylacrylamide (NIPAM) and acrylic acid (AA) to obtain PNIPAM-co-β-CD-AC. The results showed that the critical phase transition temperature of PNIPAM/β-CD-AC could be controlled at 19 °C, and the fast sol-gel phase transition was realized in 2-10 s. The hydrophobic drug carried in this hydrogel can constantly be released for more than 6 days at pH values (pH 5.5-8), and the duration may match the recovery of the wound. As a dressing hydrogel, its rapid gel formation and inversion as well as shear-thinning behavior prevent secondary wound damage. The β-CD-based hydrogel also has good biocompatibility and antioxidant properties, which provide a good potential choice for wound dressings, especially for exposed wounds in winter.

Nanotechnology-based fungal detection and treatment: current status and future perspective

Fungal infections impose a significant impact on global health and encompass major expenditures in medical treatments. Human mycoses, a fungal co-infection associated with SARS-CoV-2, is caused by opportunistic fungal pathogens and is often overlooked or misdiagnosed. Recently, there is increasing threat about spread of antimicrobial resistance in fungus, mostly in hospitals and other healthcare facilities. The diagnosis and treatment of fungal infections are associated with several issues, including tedious and non-selective detection methods, the growth of drug-resistant bacteria, severe side effects, and ineffective drug delivery. Thus, a rapid and sensitive diagnostic method and a high-efficacy and low-toxicity therapeutic approach are needed. Nanomedicine has emerged as a viable option for overcoming these limitations. Due to the unique physicochemical and optical properties of nanomaterials and newer biosensing techniques, nanodiagnostics play an important role in the accurate and prompt differentiation and detection of fungal diseases. Additionally, nano-based drug delivery techniques can increase drug permeability, reduce adverse effects, and extend systemic circulation time and drug half-life. This review paper is aimed at highlighting recent, promising, and unique trends in nanotechnology to design and develop diagnostics and treatment methods for fungal diseases.

Chitosan-Based Polymer Nanocomposites for Environmental Remediation of Mercury Pollution

Mercury is a well-known heavy metal pollutant of global importance, typically found in effluents (lakes, oceans, and sewage) and released into the atmosphere. It is highly toxic to humans, animals and plants. Therefore, the current challenge is to develop efficient materials and techniques that can be used to remediate mercury pollution in water and the atmosphere, even in low concentrations. The paper aims to review the chitosan-based polymer nanocomposite materials that have been used for the environmental remediation of mercury pollution since they possess multifunctional properties, beneficial for the adsorption of various kinds of pollutants from wastewater and the atmosphere. In addition, these chitosan-based polymer nanocomposites are made of non-toxic materials that are environmentally friendly, highly porous, biocompatible, biodegradable, and recyclable; they have a high number of surface active sites, are earth-abundant, have minimal surface defects, and are metal-free. Advances in the modification of the chitosan, mainly with nanomaterials such as multi-walled carbon nanotube and nanoparticles (Ag, TiO₂, S, and ZnO), and its use for mercury uptake by batch adsorption and passive sampler methods are discussed.

Novel Intrinsic Self-Healing Poly-Silicone-Urea with Super-Low Ice Adhesion Strength

Accumulation of snow and ice often causes problems and even dangerous situations for both industry and the general population. Passive de-icing technologies, e.g., hydrophobic, liquid-infused bionic surfaces, have attracted more and more attention compared with active de-icing technologies, e.g., electric heating, hot air heating, due to the passive de-icing technology's lower energy consumption and sustainability footprint. Using passive de-icing coatings seems to be one of the most promising solutions. However, the previously reported de-icing coatings suffer from high ice adhesion strength or short service life caused by wear. An intrinsic self-healing material based on poly-silicone-urea is developed in this work to address these problems. The material is prepared by introducing dynamic disulfide bonds into the hard phase of the polymer. Experimental results indicate that this poly-silicone-urea has a self-healing efficiency of close to 99%. More interestingly, it is found that the coating prepared from this poly-silicone-urea has a super low ice adhesion force, only 7 ± 1 kPa, which is almost the lowest value compared with previous intrinsic self-healing de-/anti-icing reports. This material can maintain low ice adhesion strength after healing. This intrinsic self-healing poly-silicone-urea can meet several practical applications, opening the door for future sustainable anti-/de-icing technologies.

Cyclodextrin-Based Nanosponges: Overview and Opportunities

Nanosponges are solid cross-linked polymeric nano-sized porous structures. This broad concept involves, among others, metal organic frameworks and hydrogels. The focus of this manuscript is on cyclodextrin-based nanosponges. Cyclodextrins are cyclic oligomers of glucose derived from starch. The combined external hydrophilicity with the internal hydrophobic surface constitute a unique "microenvironment", that confers cyclodextrins the peculiar ability to form inclusion host‒guest complexes with many hydrophobic substances. These complexes may impart beneficial modifications of the properties of guest molecules such as solubility enhancement and stabilization of labile guests. These properties complemented with the possibility of using different crosslinkers and high polymeric surface, make these sponges highly suitable for a large range of applications. Despite that, in the last 2 decades, cyclodextrin-based nanosponges have been developed for pharmaceutical and biomedical applications, taking advantage of the nontoxicity of cyclodextrins towards humans. This paper provides a critical and timely compilation of the contributions involving cyclodextrins nanosponges for those areas, but also paves the way for other important applications, including water and soil remediation and catalysis.

Nanomaterial-Based Antifungal Therapies to Combat Fungal Diseases Aspergillosis, Coccidioidomycosis, Mucormycosis, and Candidiasis

Over the last years, invasive infections caused by filamentous fungi have constituted a serious threat to public health worldwide. Aspergillus, Coccidioides, Mucorales (the most common filamentous fungi), and Candida auris (non-filamentous fungus) can cause infections in humans. They are able to cause critical life-threatening illnesses in immunosuppressed individuals, patients with HIV/AIDS, uncontrolled diabetes, hematological diseases, transplantation, and chemotherapy. In this review, we describe the available nanoformulations (both metallic and polymers-based nanoparticles) developed to increase efficacy and reduce the number of adverse effects after the administration of conventional antifungals. To treat aspergillosis and infections caused by Candida, multiple strategies have been used to develop new therapeutic alternatives, such as incorporating coating materials, complexes synthesized by green chemistry, or coupled with polymers. However, the therapeutic options for coccidioidomycosis and mucormycosis are limited; most of them are in the early stages of development. Therefore, more research needs to be performed to develop new therapeutic alternatives that contribute to the progress of this field.

Nanobiocomposite Polymer as a Filter Nanosponge for Wastewater Treatment

A multifunctional nanobiocomposite polymer was developed in this study through a cross-linking polymerization of cyclodextrin with phosphorylated multi-walled carbon nanotubes followed by sol-gel to incorporate TiO₂ and Ag nanoparticles. This work’s novelty was to prove that the developed nanobiocomposite polymer is a potential filter nanosponge capable of removing organic, inorganic, and microorganisms’ pollutants from wastewater samples. The synthesized multifunctional nanobiocomposite polymer was characterized using a range of spectroscopy and electron microscopy techniques. Fourier-transform infrared (FTIR) confirmed the presence of oxygen-containing groups on the developed nanobiocomposite polymer and carbamate linkage (NH(CO)) distinctive peak at around 1645 cm⁻¹, which is evidence that the polymerization reaction was successful. The scanning electron microscopy (SEM) image shows that the developed nanobiocomposite polymer has a rough surface. The Dubinin–Radushkevich and the pseudo-second-order kinetic models best described the adsorption mechanism of Co²⁺ and TCE’s onto pMWCNT/CD/TiO₂-Ag. The efficacy of the developed nanobiocomposite polymer to act as disinfectant material in an environmental media (e.g., sewage wastewater sample) compared to the enriched media (e.g., nutrient Muller Hinton broth) was investigated. From the results obtained, in an environmental media, pMWCNT/CD/TiO₂-Ag nanobiocomposite polymer can alter the bacteria’s metabolic process by inhibiting the growth and killing the bacteria, whereas, in enriched media, the bacteria’s growth was retarded.

Recent development in antimicrobial activity of biopolymer-inorganic nanoparticle composites with water disinfection potential: a comprehensive review

Nowadays, water-borne diseases including hepatitis remain the critical health challenge due to the inadequate supply of potable and safe water for human activities. The major cause is that the pathogenic microorganisms causing diseases have developed resistance against common techniques used by sewage water treatment plants for water disinfection. Therefore, there is a need to improve these conventional water treatment techniques by taking into consideration the application of nanotechnology for wastewater purification. The main aim of this paper is to provide a review on the synthesis of biopolymer-inorganic nanoparticle composites (BINCs), their used as antimicrobial compounds for water disinfection, as well as to elaborate on their antimicrobial mechanism of action. The microbial properties affecting the activity of antimicrobial compounds are also evaluated.

Chitosan nanocomposites for water treatment by fixed-bed continuous flow column adsorption: A review

Nowadays, access to clean water sources worldwide and particularly in Southern Africa is inadequate because of its pollution by organic, inorganic, and microorganism contaminants. A range of conventional water treatment techniques has been used to resolve the problem. However, these methods are currently facing the confronts posed by new emerging contaminants. Therefore, there is a need to develop simple and lower cost-effective water purification methods that use recyclable bio-based natural polymers such as chitosan modified with nanomaterials. These novel functional chitosan-based nanomaterials have been proven to effectively eliminate the different environmental pollutants from wastewater to acceptable levels. This paper aims to present a review of the recent development of functional chitosan modified with carbon nanostructured and inorganic nanoparticles. Their application as biosorbents in fixed-bed continuous flow column adsorption for water purification is also discussed.