In this study, cobalt ferrite (CoFe
2
O
4
) nanoparticles were synthesized by sol–gel auto-combustion technique in the presence of agarose as a natural gelling agent, and its influence on the ...morphology and magnetic properties of CoFe
2
O
4
as well as kinetic parameters of their synthesis was investigated. The synthesized samples were characterized by TG–DTA, XRD, FTIR, FE-SEM, and VSM. A highly crystalized CoFe
2
O
4
with a spinel structure was obtained by calcination at 1073 K for three hours. The agarose acted as a chelating and templating agent during the formation of CoFe
2
O
4
nanoparticles, so that it showed a significant effect not only on decreasing agglomeration but also on reducing crystallite size from 70.3 to 54.6 nm. The VSM results revealed that coercivity increased from 818 to 1076 Oe by agarose addition. Furthermore, the effect of adding agarose on the kinetic parameters and formation mechanism of CoFe
2
O
4
nanoparticles during the calcination process under a non-isothermal condition was investigated by differential thermal analysis (DTA). The results showed that agarose reduces the activation energy in CoFe
2
O
4
formation during the calcination process from 143.9 to 64.33 kJ mol
−1
. Moreover, the mechanism of this process was changed after agarose addition from Avrami–Erofeev models (A) to the phase boundary reaction (R). Overall, these results demonstrated the positive effect of agarose on the nucleation of cobalt ferrite nanoparticles.
Display omitted
Health monitoring systems that incorporate stretchable sensors can provide real-time feedback on a person's physical activity, stress levels, and overall well-being. For instance, ...stretchable sensors based on conductive hydrogels have emerged as a promising technology for monitoring physiological signals such as heart rate, respiration, and muscle activity. For developing such systems, a strain machine is accounted as the first requirement for laboratories focusing on developing conductive hydrogels as strain sensors. In this article, we present a programmable, user-friendly, and versatile 3D-printed setup designed and fabricated for measuring the strain and strain sensitivity of soft electronic materials. The setup comprises a computer (or mobile), an impedance analyzer, and the strain machine that are required for developing stretchable strain sensors in scientific laboratories. We provide a very detailed build manual on how to manufacture and use the strain machine, using an ionic conductive hydrogel based on polyacrylic acid and polyvinyl alcohol as a model system. The results demonstrated the excellent performance of the strain machine in applying programmable strain regimes to the material of interest. By offering clear instructions and a build manual, our work enables scientific researchers to construct an affordable and user-friendly strain machine to boost their research progress.
Abstract
Composite hydrogels with excellent properties can open new opportunities to terminate the need for auto/allografts in bone augmentations. However, their clinical application has been limited ...by their insufficient mechanical strength and lack of osteoinductivity. Here we report a new strategy to design an injectable bioactive double network hydrogel reinforced by inorganic calcium/magnesium phosphate cement (CMPC) hydrates to meet the mechanical performance requirements for bone regeneration. The engineered CMPC hydration endows the composite hydrogel with an appropriate gelation time and temperature for injection, which shows no harm in the defect site. CMPC hydrates could also provide a lower swelling ratio and higher biodegradation rate fitting the in vivo bone regeneration needs. In vitro and in vivo experiments prove that the ions released from inorganic particles endow biocompatibility, cell migration, adhesion, differentiation, and significantly higher bone regeneration capacity. Taken together, the simple addition of CMPC particles imparts in‐demand features that bring us closer to the clinical utilization of hydrogel‐based materials for bone regeneration.
A two-dimensional non-isothermal mathematical model has been developed for the ethane dehydrogenation reaction in a fixed-bed catalytic membrane reactor. Since ethane dehydrogenation is an ...equilibrium reaction,removal of produced hydrogen by the membrane shifts the thermodynamic equilibrium to ethylene production.For further displacement of the dehydrogenation reaction, oxidative dehydrogenation method has been used.Since ethane dehydrogenation is an endothermic reaction, the energy produced by the oxidative dehydrogenation method is consumed by the dehydrogenation reaction. The results show that the oxidative dehydrogenation method generated a substantial improvement in the reactor performance in terms of high conversions and signi ficant energy saving. It was also established that the sweep gas velocity in the shell side of the reactor is one of the most important factors in the effectiveness of the reactor.
A successful design, previously adapted for treatment of complex wastewaters in a microbial fuel cell （MFC）, was used to fabricate two MFCs, with a few changes for cost reduction and ease of ...construction. Performance and electrochemical characteristics of MFCs were evaluated in different environmental conditions （in complete darkness and presence of light）, and different flow patterns of batch and continuous in four hydraulic retention times from 8 to 30 h. Changes in chemical oxygen demand, and nitrate and phosphate concentrations were evaluated. In contrast to the microbial fuel cell operated in darkness （D-MFC） with a stable open circuit voltage of 700 mV, presence of light led to growth of other species, and consecutively low and unsteady open circuit voltage. Although the performance of the MFC subjected to light （L-MFC） was quite low and unsteady in dynamic state （internal resistance = 100 Ω, power density = 5.15 W.m-3）. it reached power density of 9.2 W.m-3 which was close to performance of D-MFC （internal resistance = 50 d, power density = 10.3 W.m-3）. Evaluated only for D-MFC, the coulombic efficiency observed in batch mode （30%） was quite higher than the maximum acquired in continuous mode （9.6%） even at the highest hydraulic retention time. In this study, changes in phosphate and different types of nitrogen existing in dairy wastewater were investigated for the first time. At hydraulic retention time of 8 h, the orthophosphate concentration in effluent was 84% higher compared to influent. Total nitrogen and total Kjeldahl nitrogen were reduced 70% and 99% respectively at hydraulic retention time of 30 h, while nitrate and nitrite concentrations increased. The microbial electrolysis cell （MEC）, revamped from D-MEC, showed the maximum gas production of 0.2 m3 H2·m-3·d-1 at 700 mV applied voltage.
Bacteria can be programmed to deliver natural materials with defined biological and mechanical properties for controlling cell growth and differentiation. Here, we present an elastic, resilient and ...bioactive polysaccharide derived from the extracellular matrix of Pantoea sp. BCCS 001. Specifically, it was methacrylated to generate a new photo crosslinkable hydrogel that we coined Pantoan Methacrylate or put simply PAMA. We have used it for the first time as a tissue engineering hydrogel to treat VML injuries in rats. The crosslinked PAMA hydrogel was super elastic with a recovery nearing 100 %, while mimicking the mechanical stiffness of native muscle. After inclusion of thiolated gelatin via a Michaelis reaction with acrylate groups on PAMA we could also guide muscle progenitor cells into fused and aligned tubes – something reminiscent of mature muscle cells. These results were complemented by sarcomeric alpha-actinin immunostaining studies. Importantly, the implanted hydrogels exhibited almost 2-fold more muscle formation and 50 % less fibrous tissue formation compared to untreated rat groups. In vivo inflammation and toxicity assays likewise gave rise to positive results confirming the biocompatibility of this new biomaterial system. Overall, our results demonstrate that programmable polysaccharides derived from bacteria can be used to further advance the field of tissue engineering. In greater detail, they could in the foreseeable future be used in practical therapies against VML.
Display omitted
•Pantoea sp. BCCS 001 yielded a bioactive, elastic, and resilient polysaccharide.•Utilized to create PAMA hydrogel to treat volumetric muscle loss injuries in rats.•PAMA hydrogel exhibits improved muscle formation and reduced fibrous tissue.•In vivo studies confirms the safety and potential for tissue engineering.
Microbial electrolysis cells (MECs) are bioelectrochemical reactors in which chemical energy stored in organic compounds are converted to hydrogen through biocatalytic oxidation by microorganisms. ...The performance of MECs is highly affected by microbial communities that are impartible parts of this technology. A better understanding of microbial interactions and competitions mechanisms, has aided the comprehension of ideas and guidelines for cost effective commercial scales design. In this study, a comprehensive review of current knowledge in the microbial characterization, enrichment, and evaluation of effective parameters of microbial community in microbial electrolysis cells for typical biohydrogen production is summarized. Some existing challenges of biocatalysts behaviors in MECs (such as undesirable microorganisms growth and deactivation of desirable species) were disclosed, and outlooks for future research were also proposed, which would aid the acquisition of knowledge and contribute to the development of MECs and their application in bioenergy production with simultaneous treatment of wastewater.
Display omitted
•The methods of microbial communities analysis were summarized.•The existing challenges of desirable biocatalysts growth were disclosed.•The symbiosis of microbial groups and ways to dominate electrogens were summarized.•The effect of operational parameters on undesirable species growth was disclosed.
Myocardial infarction (MI) is still the leading cause of mortality worldwide. The success of cell-based therapies and tissue engineering strategies for treatment of injured myocardium have been ...notably hindered due to the limitations associated with the selection of a proper cell source, lack of engraftment of engineered tissues and biomaterials with the host myocardium, limited vascularity, as well as immaturity of the injected cells. The first-generation approaches in cardiac tissue engineering (cTE) have mainly relied on the use of desired cells (e.g., stem cells) along with non-conductive natural or synthetic biomaterials for in vitro construction and maturation of functional cardiac tissues, followed by testing the efficacy of the engineered tissues in vivo. However, to better recapitulate the native characteristics and conductivity of the cardiac muscle, recent approaches have utilized electroconductive biomaterials or nanomaterial components within engineered cardiac tissues. This review article will cover the recent advancements in the use of electrically conductive biomaterials in cTE. The specific emphasis will be placed on the use of different types of nanomaterials such as gold nanoparticles (GNPs), silicon-derived nanomaterials, carbon-based nanomaterials (CBNs), as well as electroconductive polymers (ECPs) for engineering of functional and electrically conductive cardiac tissues. We will also cover the recent progress in the use of engineered electroconductive tissues for in vivo cardiac regeneration applications. We will discuss the opportunities and challenges of each approach and provide our perspectives on potential avenues for enhanced cTE. STATEMENT OF SIGNIFICANCE: Myocardial infarction (MI) is still the primary cause of death worldwide. Over the past decade, electroconductive biomaterials have increasingly been applied in the field of cardiac tissue engineering. This review article provides the readers with the leading advances in the in vitro applications of electroconductive biomaterials for cTE along with an in-depth discussion of injectable/transplantable electroconductive biomaterials and their delivery methods for in vivo MI treatment. The article also discusses the knowledge gaps in the field and offers possible novel avenues for improved cardiac tissue engineering.
Biodegradation
Biodegradation of carbon‐based nanomaterials (CBNs) has been pursued extensively in the past few years in biomedical research. However, a major drawback to progress is that ...biomolecular corona (BMC) effects on CBN biodegradation have been omitted from a large number of studies. In article number 2105649, Mehdi Mehrali and co‐workers discuss the importance of the BMC and its possible impacts on the biodegradation of CBNs.
It has been over a decade since oxidative enzymes were first used to degrade carbon‐based nanomaterials (CBNs). Although enormous progress has been achieved in this field, many questions and problems ...remain unresolved that need to be answered to usher these materials toward their true destiny. Nanobioscience researchers now know that ignoring the biomolecular corona (BMC) in nanobiomedical studies, either inadvertently or intentionally, is by no means justified. However, a major drawback to progress is that BMC effects on CBN biodegradation have been omitted from a large number of studies. What's more, many studies in the field have eliminated the BMC source in the relevant experiments. Thus, the most critical question that one needs to probe is whether the BMC and its characteristics affect the biodegradability of CBNs? In this conceptual perspective paper, recent progress and significant research in CBNs biodegradation are summarized. Then, the importance of the BMC and its possible impacts on the biodegradation of CBNs are thoroughly explored as a conceptual guide. Finally, remaining challenges and the direction of future research are provided, and barriers that need to be overcome to advance the field are discussed including recommendations regarding BMC considerations and study design and reporting guidelines.
In this conceptual perspective article, the importance of the biomolecular corona (BMC) and its possible impacts on the biodegradation of carbon‐based nanomaterials are thoroughly discussed. Directions for future research along with the remaining challenges that need to be overcome to advance the field are presented with the focus on BMC impacts, study design, and reporting guidelines.
PDF