Antibacterial smart hydrogels: New hope for infectious wound management

Millions of people die annually due to uncured wound infections. Healthcare systems incur high costs to treat wound infections. Tt is predicted to become more challenging due to the rise of multidrug-resistant conditions. During the last decades, smart antibacterial hydrogels could attract attention as a promising solution, especially for skin wound infections. These antibacterial hydrogels are termed 'smart' due to their response to specific physical and chemical environmental stimuli. To deliver different drugs to particular sites in a controlled manner, various types of crosslinking strategies are used in the manufacturing process. Smart hydrogels are designed to provide antimicrobial agents to the infected sites or are built from polymers with inherent disinfectant properties. This paper aims to critically review recent pre-clinical and clinical advances in using smart hydrogels against skin wound infections and propose the next best thing for future trends. For this purpose, an introduction to skin wound healing and disease is presented and intelligent hydrogels responding to different stimuli are introduced. Finally, the most promising investigations are discussed in their related sections. These studies can pave the way for producing new biomaterials with clinical applications

The stabilization and release performances of curcumin-loaded liposomes coated by high and low molecular weight chitosan

A comprehensive stability evaluation for curcumin-loaded liposomes (Cur-LP) coated by low (LCS) or high (HCS) molecular weight chitosan with three gradient concentrations (L: low; M: medium; H: high) was the main objective of this study. Apart from leading to a higher encapsulation efficiency (>90%), all chitosan-coated Cur-LP displayed an improved stability with respect to resistant to salt, sunlight, heat, accelerated centrifugation and long-term storage at 4 °C. Increasing the molecular weight and concentration of chitosan could effectively improve the stability of Cur-LP, in which HCS-H coatings displayed the best performance. According to the fluorescence probe analysis, the mechanical reinforcement of liposomes and the concomitant reduction in membrane fluidity accounts for the major contribution to vesicle stability. Secondly, a simulated digestion model was used to prove the applicability of sustained curcumin release, achieved by adjusting the molecular weight and concentration of the chitosan stabilizer for Cur-LP. The results of this study show that high molecular weight chitosan used at relatively high concentrations, is a promising coating material for improving the stability and sustained release of Cur-LP in vitro

Latent Thermal Energy Storage Technologies and Applications: A Review

The achievement of European climate energy objectives which are contained in the European Union's (EU) “20-20-20” targets and in the European Commission's (EC) Energy Roadmap 2050 is possible, among other things, through the use of energy storage technologies. The use of thermal energy storage (TES) in the energy system allows to conserving energy, increase the overall efficiency of the systems by eliminating differences between supply and demand for energy. The article presents different methods of thermal energy storage including sensible heat storage, latent heat storage and thermochemical energy storage, focusing mainly on phase change materials (PCMs) as a form of suitable solution for energy utilisation to fill the gap between demand and supply to improve the energy efficiency of a system . PCMs allow the storage of latent thermal energy during phase change at almost stable temperature. The article presents a classification of PCMs according to their chemical nature as organic, inorganic and eutectic and by the phase transition with their advantages and disadvantages. In addition, different methods of improving the effectiveness of the PCM materials such as employing cascaded latent heat thermal energy storage system, encapsulation of PCMs and shape-stabilisation are presented in the paper. Furthermore, the use of PCM materials in buildings, power generation, food industry and automotive applications are presented and the modelling tools for analysing the functionality of PCMs materials are compared and classified

Human-Adaptable Sensors for Wearable Healthcare Monitors

In the introduction chapter, the background, research aims, and context of the thesis have been introduced, including the significance of wearable healthcare monitors. The importance of material selection for wearable devices has been discussed, focusing on key properties such as conductivity, self-healing, elasticity, and adhesion. The review of the literature highlights the various materials used in wearable healthcare devices, including conductive fillers, conductive polymers, and other materials. The different types of sensors and sensing mechanisms for monitoring various parameters such as tissue regeneration, biomolecules, pressure and strain, pH, temperature, and humidity have been discussed. The chapter also sheds light on the fabrication methods used in wearable devices, including 3D printing and the challenges associated with it.This study investigates the development and potential applications of cutting-edge materials, known as (Conductive Adhesive Reconfigurable Elastic gum like material) CareGum, which are designed to address the limitations of traditional rigid electronics in wearable healthcare monitors. CareGum is a novel material comprised of adhesive, self-healing, and stretchable gum-like substances synthesized by crosslinking polyethylene oxide or silk fibroin. The material exhibits mechanical flexibility, electrical conductivity, and self-healing properties. By adjusting the molar ratio of components, crosslinker, and pH, the material's properties can be tailored to suit specific applications.Moreover, CareGum's multimodal sensing capabilities facilitate the simultaneous monitoring of diverse physical parameters, including pressure and strain, temperature and humidity, and pH. This opens up exciting possibilities for diagnosing and treating a wide range of medical conditions. The material's remarkable self-healing properties render it a promising candidate for use in demanding environments. CareGum's rapid self-healing time and high healing efficiency enable it to withstand harsh conditions, further broadening its potential applications in exploration robotics

Principles of electrospraying: a new approach in protection of bioactive compounds in foods

Electrospraying is a potential answer to the demands of nanoparticle fabrication such as scalability, reproducibility, and effective encapsulation in food nanotechnology. Electrospraying (and the related process of electrospinning) both show promise as a novel delivery vehicle for supplementary food compounds since the process can be carried out from an aqueous solution, at room temperature and without coagulation chemistry to produce matrices or particulates in the micro- and nano-range. The presentation of core materials at the nanoscale improves target ability to specific areas of the digestive tract and gives improved control of release rate. Adoption of these electrohydrodynamic atomization technologies will allow the industry to develop a wide range of novel high added value functional foods. To optimize production conditions and maximize throughput, a clear understanding of the mechanism of electrospraying is essential. This article presents a comprehensive review of the principles of electrospraying to produce nanoparticles suitable for food technology application, particularly for use in encapsulation and as nanocarriers

Physicochemical, Thermal, and Morphological Properties of Chitosan Nanoparticles Produced by Ionic Gelation

Chitosan nanoparticles (CSNPs) can be widely used in the food, pharmaceutical, and cosmetic sectors due to their high performance, unique properties, and high surface area. In this research, CSNPs were produced by the ionic gelation method and using sodium tripolyphosphate (STPP) as an appropriate technique compared to the conventional methods. To evaluate the effects of various factors on the size, zeta potential (ZP), and optimal synthesis conditions, different concentrations of CS (1, 3, and 5 mg/mL), STPP (0.5, 0.75, and 1 mg/mL), and CS to STPP ratio (1:1, 3:1, and 5:1) were applied and optimized using the response surface methodology. The size of CSNPs was increased by using higher concentrations of CS, STPP, and CS/STPP ratios. The value of ZP was determined positive and it increased with increasing CS concentrations and CS/STPP ratios. ATR-FTIR spectra revealed interactions between CS and STPP. The DSC thermogram of CSNPs showed a double sharp endothermic peak at about 74.5 °C (ΔH = 122.00 J/g); further, the TGA thermograms indicated the total weight loss of STPP, CS, and CSNPs as nearly 3.30%, 63.60%, and 52.00%, respectively. The XRD data also revealed a greater chain alignment in the CSNPs. Optimized, the CSNPs can be used as promising carriers for bioactive compounds where they also act as efficient stabilizers in Pickering emulsions

Stabilization of a saffron extract through its encapsulation within electrospun/electrosprayed zein structures

In this work, electrospinning and electrospraying techniques were used to encapsulate the sensitive bioactive compounds of a saffron extract (i.e. picrocrocin, safranal, and crocin) using zein as protective matrix. Initially, a dried saffron extract (DSE) was obtained and characterized and was subsequently incorporated within zein solutions prepared at two concentrations (10% w/v for capsules and 20% for fiber development). The greatest encapsulation efficiency was observed for the fiber samples, with retention values for picrocrocin, safranal, and crocin of up to 97, 88, and 97%, respectively. The stability of the free and encapsulated extract when exposed to UV light, different pH (2, 7.4) and temperatures (25, 75 °C) was also studied. The photostability of crocin and safranal was significantly (p < 0.05) increased upon encapsulation. Similarly, while about 98% of the non-encapsulated crocin degraded after 15 h of exposure to acetic acid at 75 °C, only 67.23% of the encapsulated compound was lost under the same conditions. The release profiles of crocin, safranal and picrocrocin from the encapsulation structures were fitted using the Peppas-Sahlin model (R2 = 0.98), showing that the dominant release mechanism was diffusion. Finally, the encapsulation structures retained their integrity upon contact with water, highlighting their potential use as food packaging coatings.A. Alehosseini received a scholarship by the Ministry of Science, Research and Technology (MSRT) of Iran. The authors would like to thank the Spanish MINECO project AGL2015-63855-C2-1 for financial support.Peer reviewe

Electrospun curcumin-loaded protein nanofiber mats as active/bioactive coatings for food packaging applications

In this study, curcumin was encapsulated within electrospun protein (i.e. gelatin and zein) fibers to generate bioactive coatings for food packaging. Additionally, a green tea extract (GTE) was also incorporated within the formulations to evaluate its impact on the stability, protective ability, and release properties of the curcumin-loaded fibers. Due to the poor solubility of curcumin in aqueous media, a strategy based on its incorporation through liposomes was developed, allowing to successfully incorporating curcumin into gelatin fibers. Very high encapsulation efficiencies were attained for both zein and gelatin, with the former showing an enhanced protection effect and a more limited and slower release of the curcumin in hydrophobic food simulants. The addition of GTE resulted in strong interactions being established with the proteins and, in the particular case of gelatin, it improved the protective effect and slowed down the curcumin release from the fibers, although it did not prevent their collapse in water. The results showed that while the developed gelatin coatings showed a promising release behavior in contact with fatty food simulants, zein-based coatings would be more adequate for packaging of high water content food products.A. Alehosseini received a scholarship by the Ministry of Science Research and Technology of Iran. L. G. Gómez-Mascaraque and M. Martínez-Sanz are recipients of a predoctoral (BES-2013-065883) and Juan de la Cierva (IJCI-2015-23389) contracts from the Spanish Ministry of Economy and Competitiveness (MINECO). The authors would like to thank the Spanish MINECO project AGL2015-63855-C2-1 for financial support.Peer reviewe