Abstract

Cancer vaccines based on tumor cell components have shown promising results in animal and clinical studies. The vaccine system contains abundant tumor antigen components, which can activate the immune system by antigens. However, their efficacy has been limited by the inability of antigens delivery, which are the core components of vaccines, further fail to be presented and activation of effective cells. Nanotechnology offers a novel platform to enhance the immunogenicity of tumor-associated antigens and deliver them to antigen-presenting cells (APCs) more efficiently. In addition, nanotreatment of tumor cells derivate active ingredients could also help improve the effectiveness of cancer vaccines. In this review, we summarize recent advances in the development of cancer vaccines by the combination of nanotechnology and tumor-based ingredients, including liposomes, polymeric nanoparticles, metallic nanoparticles, virus-like particles and tumor cells membrane, tumor lysate, and specific tumor antigens. These nanovaccines have been designed to increase antigen uptake, prolong antigen presentation, and modulate immune responses through codelivery of immunostimulatory agents. We also further discuss challenges and opportunities in the clinical translation of these nanovaccines.

Introduction

Cancer immunotherapy has revolutionized cancer treatment by harnessing the immune system to recognize and attack cancer cells [1–3]. Among various immunotherapeutic approaches, cancer vaccines have attracted significant attention due to their potential to induce long-lasting and specific immune responses against tumor cells [4–7]. By comparison with surgery, it hardly produce large wounds, nor does it cause higher toxicity in normal tissues and drug tolerance like chemotherapy in the treatment of tumor. However, the clinical efficacy of cancer vaccines based on tumor cell components, such as peptides and proteins, is limited by their poor immunogenicity and inefficient delivery to antigen presentation cells (APCs). Although, many cancer vaccines were applied with the immune-stimulatory agents, such as the programmed cell death protein 1 (PD-1), CpG oligonucleotide, etc. The clinical response rates remain low, especially in the hypoimmunogenic tumors. As we all know, pancreatic cancer is a more difficult type for immunotherapy as a low immunogenic tumor. Therefore, there are few effective cancer vaccines that can actively promote the pancreatic cancer treatment. Meanwhile, limited by the specific tumor antigens, the development of cancer vaccines was extremely difficult.

The field of cancer vaccines has seen significant advancements in recent years, with numerous studies focusing on different aspects of vaccine development and application [8–12]. These advances have been facilitated by the exploration of various types of cancer vaccines, including those targeting viral antigens, neoantigens, and other tumor-specific antigens [13–16]. One approach in cancer vaccine research involves targeting shared antigens from viral infections linked to certain cancer types, such as Epstein–Barr virus and HPV. Studies have shown promising results with vaccines targeting viral antigens like Epstein–Barr nuclear antigen 1 and latent membrane proteins, as well as HPV-related antigens, demonstrating favorable antitumor efficacy and the potential to establish durable T cell memory in rapidly progressing HPV-positive tumors [17]. Another significant area of research is neoantigen cancer vaccines. Neoantigens, derived from nonsynonymous cell variants, are only expressed in tumor cells and can bypass thymus-negative selection, leading to robust neoantigen-specific T cell responses [14]. Advances in genomic and transcriptional profiling have made identifying putative neoantigens possible, although challenges remain in predicting which neoantigens can effectively induce neoantigen-specific T cell responses [18–20]. Cancer vaccines are being developed to stimulate antitumor immunity with tumor antigens delivered in various forms, such as cells, peptides, viruses, and nucleic acids [21–24]. These vaccines aim to overcome tumor heterogeneity and reverse the immunosuppressive microenvironment. Challenges in the field include single antigen targeting, weak immunogenicity, off-target effects, and impaired immune response [25–27]. Current research and reviews provide insights into the principle of action, components, classification, delivery methods, and progress of cancer vaccines, offering a broader perspective for future vaccine design.

Recent studies have shown that tumor antigens can be used for the design of cancer vaccines without the necessity to identify, parse, and reconstruct certain antigens [28–31]. A novel concept has been proposed that the whole antigen vaccine systems derived from tumor cells could be designed to conquer cancer treatments [32–34]. The tumor cells themselves are a huge antigen pool with countless tumor antigen epitopes, which can be used to activate antitumor immune response. Among them, more studies have focused on the application of tumor cell membrane as tumor antigens to stimulate APCs and further activate the antitumor immune response of T cells. In addition, the activation of T cells in immune response requires the involvement of costimulatory molecules. Some studies are based on this theoretical foundation, using genetic engineering to modify tumor cell membranes. By retaining antigen on the cell membrane and inducing the expression of costimulatory molecule CD80, T cells can be directly activated, thereby achieving antitumor immune response [35] (Figure 1). Of course, many studies combine tumor cell membranes that retain tumor antigens with other functional molecules to directly activate dendritic cells (DCs) for antigen presentation, leading to the activation of T cell immune response. These are two different approaches aimed at achieving the same goal [36–38]. A series of nanovaccines developed on this basis have been widely used in the treatment of different tumor cells and preclinical experiments.

Abstract

Climate change requires transforming the production processes of high-emission industries toward low-carbon technologies. One of the main emitters of greenhouse gases is the steel industry. Therefore, steel manufacturers are planning to substitute the blast furnace-basic oxygen furnace route with hydrogen-based direct reduction and electric arc furnaces. Thus, direct greenhouse gas emissions can be avoided almost entirely. This involves changes in the materials and energies used. Besides hydrogen, natural gas is becoming more important for the direct reduction of iron ores. Therefore, future greenhouse gas emissions associated with low-carbon steelmaking are deeply intertwined with the developments of the system environment. Upon potential transformation pathways of the system environment, future greenhouse gas emissions from natural gas and hydrogen-based direct reduction coupled with electric arc furnaces are investigated. To this end, a prospective cradle-to-gate life cycle assessment approach is used. The results indicate that greenhouse gas emissions highly depend on the electricity mix if hydrogen is produced by electrolysis. Using natural gas for direct reduction is a viable short-term option until the decarbonization of the energy sector is further advanced.

Introduction

Due to climate change, it is required to decarbonize highemission industries such as the steel industry. Approximately 7% of global greenhouse gas (GHG) emissions result from steelmaking processes, especially from primary steelmaking [1]. In most cases, the coal-based blast furnace-basic oxygen furnace (BF-BOF) route is used for the primary production of crude steel [2]. However, alternative technologies for reducing direct GHG emissions of steelmaking already exist. As of today, most steel manufacturers are planning to substitute BFBOF production facilities with direct reduction plants (DRP) and electric arc furnaces (EAF) from 2025 onwards [3–5]. In this process design, sponge iron is produced within the DRP. Afterward, the sponge iron is further processed within the EAF for crude steel production. Existing DRPs are currently solely operated with natural gas (NG/DR) for direct reduction [1]. The NG/DR-EAF process serves as a transitional technology in the transformation process of integrated steel mills toward lowcarbon steelmaking. In the long term, NG/DR can be substituted by hydrogen-based direct reduction (H/DR) of iron ore. If hydrogen is used, direct GHG emissions can be reduced by up to 97% [6]. A framework for designing economically advantageous transformation pathways is developed within [7].

Conclusion

Most European steel manufacturers are planning to transform their integrated steel mills’ production infrastructure toward DR-EAF production to significantly reduce GHG emissions from primary steelmaking. This article consists of a prospective cradle-to-gate LCA approach for DR-EAF steelmaking. For environmental impact assessment, it is differentiated between NG/DR, H/DR with hydrogen from electrolysis using the German electricity mix, and H/DR with hydrogen from electrolysis using electricity from onshore wind turbines. The developed assessment provides an understanding of the environmental impacts of the DR-EAF route considering different future developments of the system environment.

This study finds that direct GHG emissions can be reduced by around 96% if H/DR-EAF production is applied to substitute the BF-BOF route. However, indirect GHG emissions are highly intertwined with future developments of the system environment. Thus, fast decarbonization of the energy sector is highly important to heavily reduce overall GHG emissions. Also, GHG emissions from raw material extraction, processing, and transportation need to be reduced to aim for a low GHG emission steel industry. Process-related, direct GHG emissions are higher when NG/DR is applied. Indirect emissions, however, are less affected by system environment developments. Thus, natural gas provides a viable short-term option for the DR process. Besides decarbonization of the system environment which needs to be driven by policymakers, steel manufacturers need to focus on measures to increase their shares of low-carbon hydrogen in the early phase of the transformation process. To this end, electrolysis capacities need to be installed if sufficient external hydrogen sources for H/DR are not available. Also, increasing the share of low-carbon electricity to operate electrolysis facilities is of high importance.

Abstract

Introduction

Wastewater in area of focus

Nanotechnology in water purifcation

Nano‑adsorption

Microbial agent

Nanocomposites

Types of nanocomposites

Synthesis modes for nanocomposites

Graphene oxide‑based composites as a disinfectant

Zinc oxide nanocomposites as disinfectant

Copper oxide nanocomposites

Silver/silver oxide nanocomposites

Titanium oxide nanocomposites

Discussion

Conclusion

References

Abstract

     Water is crucial for the existence of life. The world, however, is facing a global water crisis. There are variety of microorganisms, gases and other toxins responsible for water contamination. Various types of nanomaterials exist that have enormous potential to treat contaminated water (water containing metal toxins or specific organic or inorganic impurities) due to their unique properties such as a high surface area and their ability to work effectively even at low concentrations. In recent years, scientists have been giving considerable attention to the application of nanocomposites for water purification, wastewater treatment, microorganism elimination, chemical contaminants, heavy metals removal and so forth. The incorporation of different nanofillers such as carbon nanotubes, graphene oxide, 2D materials, zinc oxide, titanium dioxide, copper and silver nanoparticles into polymeric materials has facilitated important advances, such as suppressing the accumulation of pollutants and foulants, improving the hydrophilicity, increasing the efficiency and improving the mechanical properties. This review discusses leading advances in the development of nanocomposites for antimicrobial and wastewater treatment with the aim of providing an improved understanding of nanocomposites and their applications in antimicrobial and wastewater treatment.

Introduction

     Water is a basic requirement for human life. However, we are far from meeting global requirements for clean water, and this issue will continue to grow over the time (Hillie and Hlophe 2007; Elwakeel et al. 2020b). The demand of clean drinking water is rising as a result of the deterioration of water quality, global climate change and population growth (Tchobanoglous et al. 1991; Elwakeel et al. 2020d). Emissions of organic dyes and heavy metal ions from the paper, leather and textile industries are a serious problem, as they are potentially mutagenic and carcinogenic. To meet environmental requirements, wastewater contaminated with these organic and inorganic species need to be treated before being discharged (Santhosh et al. 2016; Elwakeel et al. 2021). Heavy metals are widely used in various industries for many purposes, including mining and pigment production. Synthetic dyes are also an important type of pollutant, and their sources for water contamination include the textile, pulp and paper, tinting, printing, painting and tanning industries. The removal of dye from such wastewater is a challenging task, as pigments and synthetic dyes are biodegradation-resistant and remain in the environment for a long time. The destruction and handling of organic dyes is therefore an important issue, and a cost-efective method for removing dye substances from wastewater has been developed (Santhosh et al. 2016; Elwakeel et al. 2018).

Conclusion

     This paper explores the existing nanocomposites used to extract heavy metal ions and dyes from wastewater as efective adsorbents. This article addressed recent developments in nanomaterials as economical and environmentally sustainable water purifcation adsorbents. This review highlights fve commonly used nanomaterials/nanoparticles that are used in most existing nanocomposites. In this review, we concluded that TiO2-based nanocomposites have been used for photodegradation activity by most of the researchers in the literature. Silver-based nanocomposites are mostly used for antimicrobial activity. Silver and GO-based nanocomposites were used for the removal of green dye, anionic dye and Cu(II). Copper-based nanocomposites are mostly used for adsorption and photodegradation activity. Zinc oxide nanocomposites are used for adsorption, antimicrobial and photodegradation activity. Finally, we concluded that GO also greatly contributes to the improvement of other materials’ efciency. Further, much needs to be done to control the two-dimensional GO sheets for advanced technologies in the future. There are many challenges and obstacles associated with handling wastewater, and many precautions are required to prevent environmental and health problems. Therefore, new modern wastewater treatment equipment should be versatile, low-cost and commercially efective.

Abstract

1. Introduction

2. Experimental

3. Results and discussion

4. Conclusion

Conflict of Interest

Supplementary Information

References

Abstract

     This study investigates the effect of graphene oxide (GO) on the mechanical and corrosion behavior, antibacterial performance, and cell response of Mg—Zn—Mn (MZM) nanocomposite. MZM/GO nanocomposites with different amounts of GO (i.e., 0.5wt%, 1.0wt%, and 1.5wt%) were fabricated by the semi-powder metallurgy method. The influence of GO on the MZM nanocomposite was analyzed through the hardness, compressive, corrosion, antibacterial, and cytotoxicity tests. The experimental results showed that, with the increase in the amount of GO (0.5wt% and 1.5wt%), the hardness value, compressive strength, and antibacterial performance of the MZM nanocomposite increased, whereas the cell viability and osteogenesis level decreased after the addition of 1.5wt% GO. Moreover, the electrochemical examination results showed that the corrosion behavior of the MZM alloy was significantly enhanced after encapsulation in 0.5wt% GO. In summary, MZM nanocomposites reinforced with GO can be used for implant applications because of their antibacterial performance and mechanical property.

Introduction

     Currently, because magnesium (Mg) alloys have more benefits than common metallic materials, ceramics, and biodegradable polymers, their biomedical applications have been increasing. In terms of mechanical features, metals have higher mechanical strength and fracture toughness than ceramics or polymers; thus, metals are more appropriate for load-bearing usages than ceramics or polymers [1–2]. The density of human cortical bone (1.75 g/cm3 ) is similar to the density of Mg (1.738 g/cm3 ) and Mg alloys (1.75–1.85 g/cm3 ) but lower than the density of biomedical titanium alloy Ti6Al4V (4.47 g/cm3 ) [3–4]. In terms of biocompatibility, certain amounts of Mg ions in the human body are connected with many metabolic reactions and biological mechanisms [5–6]. Mg alloys are suitable orthopedic and cardiovascular implants because further surgery to remove them is not needed [7–8]. However, an important drawback of Mgbased implants is that they do not have good resistance against corrosion in physiological environments [9]. Mechanical strength could be significantly reduced by rapid and uncontrollable corrosion processes, which leads to premature failure [10]. Moreover, the health of patients who have such implants could be at risk because of the evolution of hydrogen gas and alkalinization of the environments close to the interface between implant and tissue [11]. Therefore, to achieve the secure deployment of biomedical devices, the degradation/corrosion rate of Mg alloys needs to be controlled [12]. In this context, several methods, such as alloying, powder metallurgy (PM), and surface modification strategies, have been used in an extensive number of studies that aimed to solve the problem of corrosion in Mg alloys [13–14]. Among the best methods to enhance the corrosion resistance of porous Mg are PM processes, such as mechanical alloying [15–17].

Conclusion

     In this study, using the semi-powder metallurgy method, different contents of GO were embedded in the Mg–Zn–Mn (MZM) matrix to prepare MZM/xGO nanocomposites for orthopedic applications. The corrosion performance and the 24 20 16 12 8 4 0 0 −0.5 −1.0 −1.5 −2.0 Extension / mm MZM/GO Graphene oxide Graphene oxide Graphene oxide Graphene oxide Crack Crack (a) (c) 1.5GO 0.5GO 1GO MZM (b) MZM composite MZM/0.5GO MZM/1GO MZM/1.5GO 49 59 63 64 Compression strength / N 4820 17810 19960 9620 1.12 1.31 1.44 0.72 Force / (10 3 N) Micro hardness, HV Extension / mm Material nanocomposite Fig. 10.    (a) Typical compressive curves and (b) hardness and compressive strength values of the MZM/xGO nanocomposites; (c) schematic diagram of the crack deflection toughening mechanisms of GO in the MZM/xGO nanocomposites. S. Jabbarzare et al., Effect of graphene oxide on the corrosion, mechanical and biological properties of Mg-based … 317 mechanical and biological characteristics of the MZM/xGO nanocomposites were analyzed. The microstructural assessment showed that a uniform distribution was achieved in the MZM/0.5GO and MZM/1GO nanocomposite specimens. However, agglomeration was observed in the MZM/1.5GO nanocomposite specimen. The results showed that the GO content, hardness value, and compressive strength are positively associated. In this context, the MZM/1GO nanocomposite has higher hardness value and compressive strength than the Mg-based nanocomposite without GO. The MZM/ 0.5GO nanocomposite exhibited a nearly comparable corrosion resistance to the MZM/1GO nanocomposite, even though the incorporation of more GO has an unfavorable effect on the Rct value of the MZM matrix. The MTT assay results showed that the MZM/1GO nanocomposite increased the MG63 cell viability and ALP activity, indicating the increasing level of osteogenesis. The results of the analysis of antibacterial activity showed that the MZM/1.5GO nanocomposite had a noticeable effect on antibacterial effectiveness toward bacteria, including Salmonella–Shigella and Klebsiella pneumoniae. In summary, the results indicate the possibility of utilizing the MZM/1GO nanocomposite for implant applications with effective anti-infection characteristics.

Abstract

Introduction

Materials and methods

DPPH

Microbial studies

Result and discussion

Microbial studies

Conclusion

Acknowledgements

References

Abstract

     Nanotechnology involving biopolymers is comprehensively used in biomedical applications, planning sciences, and food development. The present work describes the synthesis, characterization, and application of carrageenan and zinc oxide nanoparticles (ZnONPs) based hydrogel. The synthesized hydrogels were subsequently characterized using FTIR, XRD, SEM, and TG-DTA. The swelling property, antioxidant activity, and whole blood clotting effectiveness of the Carrageenan hydrogel, and Carrageenan Hydrogels Impregnated with Zinc Oxide Nanoparticles were evaluated. The Carrageenan + ZnONPs (C/ZnONPs) hydrogels showed good antioxidant, and blood clotting activity than the pure carrageenan hydrogel. In addition, the stable C/ZnONPs hydrogels exhibit good antimicrobial activities against both Gram-negative and Gram-positive bacterial strains. Biofilm analysis showed that C/ZnONPs hydrogels have excellent anti-biofilm potential in both inhibition and disruption of preformed biofilm. The obtained results suggested that the carrageenan and Zinc oxide nanoparticles based hydrogel have promising biological applications.

Introduction

     Pathogenic microorganism resistance to frequently used antibiotic substances have become an important health concern in the 21st century. The development of microorganism resistance to antibiotics has significantly increased morbidity and mortality, longer hospitalization and increased health care costs.[1] Resistance is increasing against antibiotics, particularly to the first line, inexpensive, and broad-spectrum antibiotics, but also to the newly developed antibiotics; since the development of novel alternative is necessary.[2,3]

In the specific case of wound management there are several reports of the microorganism resistance to the drug used to manage wounds.[4] The role of microbial infections in the development of wound infections is well established, the life threatening nature of the wound infections has maximized its importance in human health. In addition, the cost of medication for wound management is also high.[5,6] Hence the exploration of new substance for the wound management is very important.

Conclusion

     The synthesized C/ZnONPs hydrogels was produced by a simple and efficient method, performing proper swelling capacity and much better mechanical properties. It exhibited better antioxidant, blood clotting activity and also possess excellent antibacterial and biofilm efficacy against B. subtilis, S. aureus, E. coli and K. pneumonia. The present study confirmed that C/ZnONPs hydrogel have multi-potential property. Thus, the present study suggests that this bio-reduction practice is a well suitable system for large-scale production. The blood clotting and biofilm efficacy were tested in this study only at the grassroot stage which needs to be addressed further.

Abstract

Introduction

Polyacrylamide hydrogels and their polymerization

Polyacrylamide hydrogel in cell biology and drug delivery system

Classification of hydrogels: a broad overview

Homo-polymeric hydrogels

Co-polymer hydrogels

Semi-interpenetrating network

Interpenetrating network

Recent progress (2019–2022) of polyacrylamide-based hydrogel composites

Swelling and degradation behaviour of PAM hydrogels

Mechanical properties of PAM hydrogel composites

Tribological and rheological properties of PAM composites

Magnetic hydrogel composites

Biological properties of the PAM hydrogel composites

Applications of polyacrylamide hydrogels

Conclusions

Scope for the future work

Acknowledgements

References

Abstract

     Polyacrylamide hydrogels have made an immensely important place in various fields having bio-compatibility, high water-holding capacity, tunability and cheap synthesis, which has attracted researchers’ attention. Polyacrylamide can be chemically infused with other elements or compounds to find applications in magnetic biosensors, drug delivery, cartilage repair and wound dressing. This paper throws light on the brief introduction of hydrogels and their classification. The polymerization method of polyacrylamide hydrogel followed by its clinical uses (cell biology and drug delivery) is adorned in the report. Keeping at the centre, the recent highlights on the research work done on polyacrylamide hydrogel composites using various reinforcing additives are crucially explored first time in the present report. The improvement practice in the strength, bonding and self-healing of the polyacrylamide hydrogel is demonstrated by the encapsulation of nanoparticles like silicon, carbon nanotubes, gelatine, cellulose, etc. The clinical aspects of the polyacrylamide are corroborated by the cell viability, proliferation and migration. Thus, polyacrylamide hydrogels are emerging candidates, precisely illuminated in the review, which can be an influential highlight designed for upcoming research.

Introduction

     Hydrogels are flexible polymers with excellent biocompatibility. Due to their three-dimensional network, hydrogels have high water-holding capacity. Further, hydrogels have the ability to form blends by using more than one monomers and cross-linkers. Chemical infusion of hydrogels has also been tested with several biocompatible materials. These hydrogel composites are tested for a ‘new generational’ changes in existing applications. This infusion using corresponding salts followed by reduction using a suitable reducing agent forms nanoparticles suspended in the hydrogel. Research in magnetic bio-sensing materials has tested hydrogels infused with magnetic nanoparticles also called ferrogels. For applications like cartilage replacement as well, hydrogel-based composites are carefully prepared for specific cartilage-like properties [1, 2]. Gels are formed when crosslinker forms bonds laterally linking two polymeric chains. This is much like the two sugar phosphate DNA backbones that are joined by chromosome pairs. Except that, the polymeric chains are flexible, unlike DNA backbones! Without cross-linking, the polymeric chains will dissolve into the aqueous phase and only interaction between the chains is through a physical bond. Cross-linking also decides the strength-related properties of the gel. Optimizing the cross-linking method and the cross-linking ratio is essential for strength-related properties.

Conclusions

     Polyacrylamide hydrogels are emerging polymers due to their unique properties, which have made them useful in fields like cartilage repair, wound dressing, contact lenses, drug delivery and biosensors. The PAM hydrogel can be prepared by a monomer unit along with a cross-linker mixed in a suitable quantity. The PAM composites were fabricated by introducing some nanoparticles and reducing them to change these cations/anions into metal ions. The present review described the introduction of hydrogels with their different types, based on the polymeric network structure. The PAM hydrogels along with different nanoparticles like TiO2 and CNTs are turned with high strength ([ 0.43 and 2.340 MPa compressive strength and elastic modulus, respectively) composites. However, the puncture resistant of the PAM was also enhanced with these nanoparticles, estimated using the needle insertion technique. The tribological and magnetic investigations (magnetic saturation 1.41 emu/g) revealed an improved performance of PAM with encapsulation of nanoparticles due to the fine-grained structure and lubrication effects (created by CNTs). Furthermore, the biological activity of PAM composites was remarkably important and ideal for the implementation in biomedical research. Thus, in short, this review report is an important highlight for PAM hydrogel composites and can provide a prominent direction to future research based on the PAM hydrogels for biomedical applications.

Abstract

Introduction

Materials and methods

Characterizations

Results and discussion

Optimized reaction conditions

FTIR spectra analysis

SEM–EDS analysis

XRD analysis

TGA analysis

Conclusion

Declarations

References

Abstract

     An interpenetrating polymer network (IPN) containing gum acacia (GA), poly(methacrylic acid) (MAA), and poly(acrylic acid) (AA) was developed using a two-step aqueous polymerization method. Firstly, semi-IPNs were produced by radical polymerization of MAA chains onto GA in the presence of ammonium persulfate as a free radical initiator and N, N′-methylene-bisacrylamide (MBA) as a cross-linking agent using a microwave heating. To obtain a semi-IPN with a higher swelling percentage, several reaction parameters such as initiator, monomer, and crosslinker concentrations were varied. The percentage swelling (%S) was highly dependent upon the reaction conditions. The optimal reaction conditions for maximal %S were 2.55 × 10–2 mol/L initiator concentration, 12 mL solvent, 0.424 × 10–3 mol/L of monomer, and 2.16 × 10–2 mol/L cross-linker concentration, according to the findings. GA-g-poly(MAA) was the name to given to the semi-IPN. Second, IPN was created by grafting AA chains onto a GA-g-poly(MAA) matrix that had been optimized. The IPN was named as a GA-g-poly(MAA-IPN-AA). The reduction of silver ions to silver nanoparticles (AgNPs) was carried out by heating the mixture of flower extract of Koelreuteria apiculate under microwave radiation.

Introduction

     Hydrogels are three-dimensional (3D) networks formed by the crosslinking of hydrophilic polymers [1, 2]. They might swell while maintaining their network structure by absorbing signifcant amounts of water or biological fluids. The inclusion of hydrophilic groups such as -OH, -CONH, -CONH2, -COOH, and -SO3H along the polymer chain contributes to their ability to absorb a large amount of water [1]. Polysaccharide hydrogel networks have received a lot of attention in recent years [3–5]. The physico-chemical properties of these hydrogels frequently differ significantly from those of the macromolecular constituents. Hydrogel characteristics can also be altered utilizing a range of physical and chemical crosslinking techniques [3, 6]. Various researchers have examined a number of polymeric systems to create hydrogels [7]. The polymer composition can be classified as natural polymeric hydrogels, synthetic polymer hydrogels, and or a combination of both [7]. Because of their non-toxicity, low cost, permeability, and biocompatibility, hydrogels have gotten a lot of attention in a variety of sectors [8–10].

Conclusion

     Antimicrobial materials have been studied extensively in response to rising microbial resistance to traditional antibiotics and disinfectants. Natural polysaccharidebased hydrogels and their composites containing metal nanoparticles could be suitable for antibacterial applications in some cases. Using a microwave irradiation approach, we were able to successfully synthesis GA-gpoly(MAA) and GA-g-poly(MAA-IPN-AA) based hydrogels from GA. APS and MBA being used as initiator and cross-linker, respectively. To achieve maximum %S of semi-IPN (588%) and IPN (500%), diferent parameters were optimized. The formation of cross-linked hydrogels and hydrogel composites with AgNPs was successfully demonstrated using FTIR analysis. The SEM investigation of hydrogel networks reveals a variety of morphologies, which could be attributed to structural diferences between semi-IPN, IPN, and their composites with AgNPs. SemiIPN, IPN and their composite showed superb antibacterial potential against E. coli, M. luteus, P. aeruginosa, Rihzobium species, and S. aureus, and may be used to treat a variety of infected efuents. Such interconnected hydrogels will give superior material properties, particularly in biomedical research, to prevent biomaterialassociated infections as well as general pathogenic invasions into the body. The synthesized hydrogel samples will lead to enhanced applications in the future, as well as a deeper knowledge of material interactions. The eforts to improve the property profle of cross-linked hydrogels are still on, with the hope of improving overall performance in terms of water uptake capacity, biocompatibility, and biodegradability.

Abstract

1. Introduction

2. Experimental section

3. Result

4. Discussion

5. Conclusion

Declaration of competing interest

Acknowledgements

References

Abstract

     Hydrogel is a nature scaffold that can degraded in animal body and can be used as a drug delivery system, we hypothesized that patch made of three layers of hydrogel with different PLGA nanoparticle drugs (bio-patch) can be used to decrease venous neointimal hyperplasia. Rat inferior vena cava (IVC) patch venoplasty model was used. Samples from rat IVC direct suture (DS), decellularized thoracic artery patch (TA) venoplasty and bovine pericardial patch (BPP) venoplasty were examined at day 14 after implantation. Sodium alginate and hyaluronic acid (SA/HA) hydrogel was used, three layers hydrogel patch (control) and three layers hydrogel patch with PLGA nanoparticle drugs (bio-patch) were used in rat IVC venoplasty. Patches were harvested at day 14 and analyzed. In rats, TA and BPP patch showed a thicker neointima and adventitia compared to the DS, there were larger numbers of CD68 and PCNA positive cells in both groups. The control hydrogel patch showed much thinner neointima and adventitia compared to TA and BPP patches. In both of the neointima and peri-patch area, bio-patch showed significantly fewer smooth muscle cells, fewer CD68, fewer PCNA positive cells, fewer collagen-1 positive cells, fewer p-smad2 positive cells, fewer TNF-α positive cells compared to control hydrogel patch. Bio-patch made of hydrogel and PLGA nanoparticle drugs showed a thinner neointimal thickness, and is biocompatible to the animal body.

Introduction

     Prosthetic vascular grafts like Dacron and expanded poly tetra fluoroethylene (ePTFE) have a lower patency rate in peripheral bypass surgeries [1,2]. Both grafts showed poor long-term patency rate when the diameter is smaller than 6 ​mm [3]. In addition, biological graft like cryopreserved allografts, bovine or porcine pericardium, are also commonly developed as vascular grafts [[4], [5], [6]]. However, these materials have a risk of infection, foreign body reaction as non-autologous materials, meanwhile they cannot be absorbed by the body, which limit their application [7]. Along with the advancement of material science and technologies, various of novel materials are emerging and under investigation in vascular surgery [[8], [9], [10]]. Decellularized fish swim bladder also showed potential application as tube and patch grafts [3], plant leaf can also be used a patch to repair rat inferior vena cava (IVC) [11,12]. Great progress has been made in the field of vascular patches recently, however, the big challenge of neointima formation still not be solved [13,14].

Conclusion

     In conclusion, we showed a novel idea to fabricate a three layers vascular patch with different PLGA nanoparticle drugs (bio-patch), this bio-patch can effectively decrease neointimal hyperplasia in a rat IVC venoplasty model; this research showed that the bio-patch may be a potential substitute of other prosthetic patches in vascular surgery.

Abstract

     Two dimensional nanomaterials, such as graphene and MXene, have been widely used to fabricate high performance nanocomposite films owing to their unique structure and excellent physiochemical properties, showing enormous potential applications in many areas. However, the existing voids and wrinkling in the nanocomposite films inevitably impedes realizing the high performance of the nanocomposite films during the assembly process of graphene and MXene nanosheets. Nacre provides an inspiration for fabricating high performance graphene and MXene nanocomposite films through constructing a high alignment structure and strong interface interactions. In this review, we summarize the preparation approaches of graphene and MXene nanocomposite films and discuss the mechanical properties. Then, several effective strategies for assembling graphene and MXene nanosheets have been concluded and discussed. Meanwhile, we also summarize and discuss the applications of graphene and MXene nanocomposite films including electromagnetic interference (EMI) shielding and thermal management. Finally, outlooks and challenges are proposed to promote their progress and applications in the future.

Introduction

     Since the first discovery of graphene in 2004, graphene has gradually aroused widespread attention [1]. Due to the outstanding mechanical, electrical and thermal properties, graphene has been applied in flexible electronic devices, aerospace and thermal management fields in the past decade [2], [3], [4], [5], [6]. For instance, the single-layer graphene has a Young’s modulus of 1.0 TPa [7] and a superhigh thermal conductivity of about 5300 W/mK [8] at room temperature, demonstrating enormous practical potentiality in the above mentioned fields. Before realizing these applications, it is crucial to assemble graphene nanosheets into high performance graphene nanocomposites including one dimensional (1D) fiber, two dimensional (2D) film and three dimensional (3D) bulk. Especially, high performance graphene nanocomposite films have gained enormous attention. However, it is difficult to achieve high performance nanocomposite films due to weak interaction between adjacent graphene nanosheets. Graphene oxide (GO) is a usual precursor for obtaining graphene with plentiful surface terminating groups, which can easily interact with various materials for preparing nanocomposite films [9,10]. Meanwhile, in recent years, MXene, a novel two dimensional (2D) materials, shows promising electrical and thermal properties, which shows promising application in aerospace field [11], [12], [13], [14], [15], [16]. Indeed, compared with graphene, the intrinsic mechanical and thermal conductivity properties and stabilities of MXene is relatively poor. Furthermore, the easily oxidizable characteristics and thermal vulnerability of MXene may restrict its practical applications. However, compared with graphene, MXene has plentiful surface functional groups, which is an ideal building block for fabricating nanocomposite films without chemical modification any more.

Summary and outlook

     In the past several years, two dimensional materials such as graphene and MXene have been widely studied owing to the excellent physiochemical properties. In this review, we have focused on the preparation methods, assembling strategies and mechanical properties of graphene and MXene nanocomposite films. Moreover, we have also discussed the applications of obtained graphene and MXene nanocomposite films such as EMI shielding and thermal conductivity. Various methods such as VAF, blade coating, drop casting and LbL have been used to prepare high performance graphene and MXene nanocomposite films. However, as aforementioned, the existing voids and wrinkling are harmful for the mechanical properties of graphene and MXene nanocomposite films. Hence, several strategies for fabricating high performance graphene and MXene nanocomposite films are proposed.