Chitosan-Based Beads Incorporating Inorganic-Organic Composites for Copper Ion Retention in Aqueous Solutions.

In recent years, there has been a challenging interest in developing low-cost biopolymeric materials for wastewater treatment. In the present work, new adsorbents, based on different types of chitosan (commercial, commercial chitin-derived chitosan and chitosan synthesized from shrimp shell waste) and inorganic-organic composites have been evaluated for copper ions removal. The efficacy of the synthesis of chitosan-based composite beads has been determined by studying various characteristics using several techniques, including FTIR spectroscopy, X-ray diffraction, porosimetry (N2 adsorption), and scanning electron microscopy (SEM). Adsorption kinetics was performed using different adsorption models to determine the adsorption behavior of the materials in the aqueous media. For all composite beads, regardless of the type of chitosan used, good capacity to remove copper ions from simulated waters was observed (up to 17 mg/g), which proves that the new materials hold potential for heavy metal retention. However, the adsorption efficiency was influenced by the type of chitosan used. Thus, for the series where commercial chitosan (CC) was used, the removal efficiency was approximately 29%; for the series with chitosan obtained from commercial chitin (SC), the removal efficiency was approximately 34%; for the series with chitosan enriched with CaCO3 (SH), the removal efficiency was approximately 52%.

Nanoengineered biomimetic hydrogels: A major advancement to fabricate 3D-printed constructs for regenerative medicine.

Nanostructured compounds already validated as performant reinforcements for biomedical applications together with different fabrication strategies have been often used to channel the biophysical and biochemical features of hydrogel networks. Ergo, a wide array of nanostructured compounds has been employed as additive materials integrated with hydrophilic networks based on naturally-derived polymers to produce promising scaffolding materials for specific fields of regenerative medicine. To date, nanoengineered hydrogels are extensively explored in (bio)printing formulations, representing the most advanced designs of hydrogel (bio)inks able to fabricate structures with improved mechanical properties and high print fidelity along with a cell-interactive environment. The development of printing inks comprising organic-inorganic hybrid nanocomposites is in full ascent as the impact of a small amount of nanoscale additive does not translate only in improved physicochemical and biomechanical properties of bioink. The biopolymeric nanocomposites may even exhibit additional particular properties engendered by nano-scale reinforcement such as electrical conductivity, magnetic responsiveness, antibacterial or antioxidation properties. The present review focus on hydrogels nanoengineered for 3D printing of biomimetic constructs, with particular emphasis on the impact of the spatial distribution of reinforcing agents (0D, 1D, 2D). Here, a systematic analysis of the naturally-derived nanostructured inks is presented highlighting the relationship between relevant length scales and size effects that influence the final properties of the hydrogels designed for regenerative medicine.

Development of Biocomposite Alginate-Cuttlebone-Gelatin 3D Printing Inks Designed for Scaffolds with Bone Regeneration Potential.

Fabrication of three-dimensional (3D) scaffolds using natural biomaterials introduces valuable opportunities in bone tissue reconstruction and regeneration. The current study aimed at the development of paste-like 3D printing inks with an extracellular matrix-inspired formulation based on marine materials: sodium alginate (SA), cuttlebone (CB), and fish gelatin (FG). Macroporous scaffolds with microporous biocomposite filaments were obtained by 3D printing combined with post-printing crosslinking. CB fragments were used for their potential to stimulate biomineralization. Alginate enhanced CB embedding within the polymer matrix as confirmed by scanning electron microscopy (ESEM) and micro-computer tomography (micro-CT) and improved the deformation under controlled compression as revealed by micro-CT. SA addition resulted in a modulation of the bulk and surface mechanical behavior, and lead to more elongated cell morphology as imaged by confocal microscopy and ESEM after the adhesion of MC3T3-E1 preosteoblasts at 48 h. Formation of a new mineral phase was detected on the scaffold's surface after cell cultures. All the results were correlated with the scaffolds' compositions. Overall, the study reveals the potential of the marine materials-containing inks to deliver 3D scaffolds with potential for bone regeneration applications.

Chitosan-Based Materials Featuring Multiscale Anisotropy for Wider Tissue Engineering Applications.

We designed graphene oxide composites with increased morphological and structural variability using fatty acid-coupled polysaccharide co-polymer as the continuous phase. The matrix was synthesized by N, O-acylation of chitosan with palmitic and lauric acid. The obtained co-polymer was crosslinked with genipin and composited with graphene oxide. FTIR spectra highlighted the modification and multi-components interaction. DLS, SEM, and contact angle tests demonstrated that the conjugation of hydrophobic molecules to chitosan increased surface roughness and hydrophilicity, since it triggered a core-shell macromolecular structuration. Nanoindentation revealed a notable durotaxis gradient due to chitosan/fatty acid self-organization and graphene sheet embedment. The composited building blocks with graphene oxide were more stable during in vitro enzymatic degradation tests and swelled less. In vitro viability, cytotoxicity, and inflammatory response tests yielded promising results, and the protein adsorption test demonstrated potential antifouling efficacy. The robust and stable substrates with heterogeneous architecture we developed show promise in biomedical applications.

Graphene-Oxide Porous Biopolymer Hybrids Enhance In Vitro Osteogenic Differentiation and Promote Ectopic Osteogenesis In Vivo.

Over the years, natural-based scaffolds have presented impressive results for bone tissue engineering (BTE) application. Further, outstanding interactions have been observed during the interaction of graphene oxide (GO)-reinforced biomaterials with both specific cell cultures and injured bone during in vivo experimental conditions. This research hereby addresses the potential of fish gelatin/chitosan (GCs) hybrids reinforced with GO to support in vitro osteogenic differentiation and, further, to investigate its behavior when implanted ectopically. Standard GCs formulation was referenced against genipin (Gp) crosslinked blend and 0.5 wt.% additivated GO composite (GCsGp/GO 0.5 wt.%). Pre-osteoblasts were put in contact with these composites and induced to differentiate in vitro towards mature osteoblasts for 28 days. Specific bone makers were investigated by qPCR and immunolabeling. Next, CD1 mice models were used to assess de novo osteogenic potential by ectopic implantation in the subcutaneous dorsum pocket of the animals. After 4 weeks, alkaline phosphate (ALP) and calcium deposits together with collagen synthesis were investigated by biochemical analysis and histology, respectively. Further, ex vivo materials were studied after surgery regarding biomineralization and morphological changes by means of qualitative and quantitative methods. Furthermore, X-ray diffraction and Fourier-transform infrared spectroscopy underlined the newly fashioned material structuration by virtue of mineralized extracellular matrix. Specific bone markers determination stressed the osteogenic phenotype of the cells populating the material in vitro and successfully differentiated towards mature bone cells. In vivo results of specific histological staining assays highlighted collagen formation and calcium deposits, which were further validated by micro-CT. It was observed that the addition of 0.5 wt.% GO had an overall significant positive effect on both in vitro differentiation and in vivo bone cell recruitment in the subcutaneous region. These data support the GO bioactivity in osteogenesis mechanisms as being self-sufficient to elevate osteoblast differentiation and bone formation in ectopic sites while lacking the most common osteoinductive agents.

3D Printable Composite Biomaterials Based on GelMA and Hydroxyapatite Powders Doped with Cerium Ions for Bone Tissue Regeneration.

The main objective was to produce 3D printable hydrogels based on GelMA and hydroxyapatite doped with cerium ions with potential application in bone regeneration. The first part of the study regards the substitution of Ca2+ ions from hydroxyapatite structure with cerium ions (Ca10-xCex(PO4)6(OH)2, xCe = 0.1, 0.3, 0.5). The second part followed the selection of the optimal concentration of HAp doped, which will ensure GelMA-based scaffolds with good biocompatibility, viability and cell proliferation. The third part aimed to select the optimal concentrations of GelMA for the 3D printing process (20%, 30% and 35%). In vitro biological assessment presented the highest level of cell viability and proliferation potency of GelMA-HC5 composites, along with a low cytotoxic potential, highlighting the beneficial effects of cerium on cell growth, also supported by Live/Dead results. According to the 3D printing experiments, the 30% GelMA enriched with HC5 was able to generate 3D scaffolds with high structural integrity and homogeneity, showing the highest suitability for the 3D printing process. The osteogenic differentiation experiments confirmed the ability of 30% GelMA-3% HC5 scaffold to support and efficiently maintain the osteogenesis process. Based on the results, 30% GelMA-3% HC5 3D printed scaffolds could be considered as biomaterials with suitable characteristics for application in bone tissue engineering.

Redox Mechanism of Azathioprine and Its Interaction with DNA.

The electrochemical behavior and the interaction of the immunosuppressive drug azathioprine (AZA) with deoxyribonucleic acid (DNA) were investigated using voltammetric techniques, mass spectrometry (MS), and scanning electron microscopy (SEM). The redox mechanism of AZA on glassy carbon (GC) was investigated using cyclic and differential pulse (DP) voltammetry. It was proven that the electroactive center of AZA is the nitro group and its reduction mechanism is a diffusion-controlled process, which occurs in consecutive steps with formation of electroactive products and involves the transfer of electrons and protons. A redox mechanism was proposed and the interaction of AZA with DNA was also investigated. Morphological characterization of the DNA film on the electrode surface before and after interaction with AZA was performed using scanning electron microscopy. An electrochemical DNA biosensor was employed to study the interactions between AZA and DNA with different concentrations, incubation times, and applied potential values. It was shown that the reduction of AZA molecules bound to the DNA layer induces structural changes of the DNA double strands and oxidative damage, which were recognized through the occurrence of the 8-oxo-deoxyguanosine oxidation peak. Mass spectrometry investigation of the DNA film before and after interaction with AZA also demonstrated the formation of AZA adducts with purine bases.

In Vitro Macrophage Immunomodulation by Poly(ε-caprolactone) Based-Coated AZ31 Mg Alloy.

Due to its excellent bone-like mechanical properties and non-toxicity, magnesium (Mg) and its alloys have attracted great interest as biomaterials for orthopaedic applications. However, their fast degradation rate in physiological environments leads to an acute inflammatory response, restricting their use as biodegradable metallic implants. Endowing Mg-based biomaterials with immunomodulatory properties can help trigger a desired immune response capable of supporting a favorable healing process. In this study, electrospun poly(ε-caprolactone) (PCL) fibers loaded with coumarin (CM) and/or zinc oxide nanoparticles (ZnO) were used to coat the commercial AZ31 Mg alloy as single and combined formulas, and their effects on the macrophage inflammatory response and osteoclastogenic process were investigated by indirect contact studies. Likewise, the capacity of the analyzed samples to generate reactive oxygen species (ROS) has been investigated. The data obtained by attenuated total reflection Fourier-transform infrared (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS) analyses indicate that AZ31 alloy was perfectly coated with the PCL fibers loaded with CM and ZnO, which had an important influence on tuning the release of the active ingredient. Furthermore, in terms of degradation in phosphate-buffered saline (PBS) solution, the PCL-ZnO- and secondary PCL-CM-ZnO-coated samples exhibited the best corrosion behaviour. The in vitro results showed the PCL-CM-ZnO and, to a lower extent, PCL-ZnO coated sample exhibited the best behaviour in terms of inflammatory response and receptor activator of nuclear factor kappa-B ligand (RANKL)-mediated differentiation of RAW 264.7 macrophages into osteoclasts. Altogether, the results obtained suggest that the coating of Mg alloys with fibrous PCL containing CM and/or ZnO can constitute a feasible strategy for biomedical applications.

Development of New Collagen/Clay Composite Biomaterials.

The fabrication of collagen-based biomaterials for skin regeneration offers various challenges for tissue engineers. The purpose of this study was to obtain a novel series of composite biomaterials based on collagen and several types of clays. In order to investigate the influence of clay type on drug release behavior, the obtained collagen-based composite materials were further loaded with gentamicin. Physiochemical and biological analyses were performed to analyze the obtained nanocomposite materials after nanoclay embedding. Infrared spectra confirmed the inclusion of clay in the collagen polymeric matrix without any denaturation of triple helical conformation. All the composite samples revealed a slight change in the 2-theta values pointing toward a homogenous distribution of clay layers inside the collagen matrix with the obtaining of mainly intercalated collagen-clay structures, according X-ray diffraction analyses. The porosity of collagen/clay composite biomaterials varied depending on clay nanoparticles sort. Thermo-mechanical analyses indicated enhanced thermal and mechanical features for collagen composites as compared with neat type II collagen matrix. Biodegradation findings were supported by swelling studies, which indicated a more crosslinked structure due additional H bonding brought on by nanoclays. The biology tests demonstrated the influence of clay type on cellular viability but also on the antimicrobial behavior of composite scaffolds. All nanocomposite samples presented a delayed gentamicin release when compared with the collagen-gentamicin sample. The obtained results highlighted the importance of clay type selection as this affects the performances of the collagen-based composites as promising biomaterials for future applications in the biomedical field.

Grafting versus Crosslinking of Silk Fibroin-g-PNIPAM via Tyrosine-NIPAM Bridges.

This paper reports the synthesis and complex characterization of novel polymeric networks based on the crosslinking of Bombyx mori silk fibroin via poly(N-isopropylacrylamide) bridges generated by an ammonium cerium nitrate redox system. The research study gives an understanding of the polymerization mechanism in terms of the generation of radical sites, radical growth and termination reaction, as well as the involvement of modifications on silk fibroin structure and properties. The physico-chemical characterization was carried out by FTIR-ATR, X-ray photoelectron spectroscopy and RAMAN spectroscopy with unravelling the chemical modification. The structural characterization and spatial arrangement by secondary structure were carried out by X-ray diffraction and circular dichroism. The thermal behavior and thermal stability were evaluated by differential scanning calorimetry and thermogravimetric analysis. The novel complex polymer network is intended to be used in the field of smart drug delivery systems.

Nanocomposite particles with improved microstructure for 3D culture systems and bone regeneration.

Nano-apatite and gelatin-alginate hydrogel microparticles have been prepared by a one-step synthesis combined with electrostatic bead generation, for the reconstruction of bone defects. Based on the analysis of bone composition, architecture and embryonic intramembranous ossification, a bio-inspired fabrication has been developed. Accordingly, the mineral phase has been in situ synthesized, calcifying the hydrogel matrix while the latter was crosslinked, finally generating microparticles that can assemble into a bone defect to ensure interconnected pores. Although nano-apatite-biopolymer composites have been widely investigated, microstructural optimization to provide improved distribution and stability of the mineral is rarely achieved. The optimization of the developed method progressively resulted in two types of formulations (15P and 7.5P), with 15 and 7.5 (wt%) phosphate content in the initial precursor. The osteolytic potential was investigated using differentiated macrophages. A commercially available calcium phosphate bone graft substitute (Eurocer 400) was incorporated into the hydrogel, and the obtained composites were in vitro tested for comparison. The cytocompatibility of the microparticles was studied with mouse osteoblast-like cell line MC3T3-E1. Results indicated the best in vitro performance have been obtained for the sample loaded with 7.5P. Preliminary evaluation of biocompatibility into a critical size (3 mm) defect in rabbits showed that 7.5P nanocomposite is associated with newly formed bone in the proximity of the microparticles, after 28 days.

Hybrid networks based on epoxidized camelina oil.

Lately, renewable resources received great attention in the macromolecular compounds area, regarding the design of the monomers and polymers with different applications. In this study the capacity of several modified vegetable oil-based monomers to build competitive hybrid networks was investigate, taking into account thermal and mechanical behavior of the designed materials. In order to synthesize such competitive nanocomposites, the selected renewable raw material, camelina oil, was employed due to the non-toxicity and biodegradability behavior. General properties of epoxidized camelina oil-based materials were improved by loading of different types of organic-inorganic hybrid compounds - polyhedral oligomeric silsesquioxane (POSS) bearing one (POSS1Ep) or eight (POSS8Ep) epoxy rings on the cages. In order to identify the chemical changes occurring after the thermal curing reactions, FT-IR spectrometry was employed. The new synthesized nanocomposites based on epoxidized camelina oil (ECO) were characterized by dynamic mechanical analyze and thermogravimetric analyze. The morphology of the ECO-based materials was investigate by scanning electron microscopy and supplementary information regarding the presence of the POSS compounds were establish by energy dispersive X-ray analysis and X-ray photoelectron spectroscopy. The smooth materials without any separation phase indicates a well dispersion of the Si-O-Si cages within the organic matrix and the incorporation of this hybrid compounds into the ECO network demonstrates to be a well strategy to improve the thermal and mechanical properties, simultaneously.

Fabrication of k-Carrageenan/Alginate/Carboxymethyl Cellulose basedScaffolds via 3D Printing for Potential Biomedical Applications.

Three-dimensional (3D) printing technology was able to generate great attention because of its unique methodology and for its major potential to manufacture detailed and customizable scaffolds in terms of size, shape and pore structure in fields like medicine, pharmaceutics and food. This study aims to fabricate an ink entirely composed of natural polymers, alginate, k-carrageenan and carboxymethyl cellulose (AkCMC). Extrusion-based 3D printing was used to obtain scaffolds based on a crosslinked interpenetrating polymer network from the alginate, k-carrageenan, carboxymethyl cellulose and glutaraldehide formulation using CaCl2, KCl and glutaraldehyde in various concentrations of acetic acid. The stabile bonding of the crosslinked scaffolds was assessed using infrared spectroscopy (FT-IR) as well as swelling, degradation and mechanical investigations. Moreover, morphology analysis (µCT and SEM) confirmed the 3D printed samples' porous structure. In the AkCMC-GA objects crosslinked with the biggest acetic acid concentration, the values of pores and walls are the highest, at 3.9 × 10-2 µm-1. Additionally, this research proves the encapsulation of vitamin B1 via FT-IR and UV-Vis spectroscopy. The highest encapsulation efficiency of vitamin B1 was registered for the AkCMC-GA samples crosslinked with the maximum acetic acid concentration. The kinetic release of the vitamin was evaluated by UV-Vis spectroscopy. Based on the results of these experiments, 3D printed constructs using AkCMC-GA ink could be used for soft tissue engineering applications and also for vitamin B1 encapsulation.

Three-Dimensional-Printed Sodium Alginate and k-Carrageenan-Based Scaffolds with Potential Biomedical Applications.

This work reports the development of a marine-derived polysaccharide formulation based on k-Carrageenan and sodium alginate in order to produce a novel scaffold for engineering applications. The viscoelastic properties of the bicomponent inks were assessed via rheological tests prior to 3D printing. Compositions with different weight ratios between the two polymers, without any crosslinker, were subjected to 3D printing for the first time, to the best of our knowledge, and the fabrication parameters were optimized to ensure a controlled architecture. Crosslinking of the 3D-printed scaffolds was performed in the presence of a chloride mixture (CaCl2:KCl = 1:1; v/v) of different concentrations. The efficiency of the crosslinking protocol was evaluated in terms of swelling behavior and mechanical properties. The swelling behavior indicated a decrease in the swelling degree when the concentration of the crosslinking agent was increased. These results are consistent with the nanoindentation measurements and the results of the macro-scale tests. Moreover, morphology analysis was also used to determine the pore size of the samples upon freeze-drying and the uniformity and micro-architectural characteristics of the scaffolds. Overall, the registered results indicated that the bicomponent ink, Alg/kCG = 1:1 may exhibit potential for tissue-engineering applications.

Retention of Ciprofloxacin and Carbamazepine from Aqueous Solutions Using Chitosan-Based Cryostructured Composites.

Water pollution is becoming a great concern at the global level due to highly polluted effluents, which are charged year by year with increasing amounts of organic residues, dyes, pharmaceuticals and heavy metals. For some of these pollutants, the industrial treatment of wastewater is still relevant. Yet, in some cases, such as pharmaceuticals, specific treatment schemes are urgently required. Therefore, the present study describes the synthesis and evaluation of promising cryostructured composite adsorbents based on chitosan containing native minerals and two types of reinforcement materials (functionalized kaolin and synthetic silicate microparticles). The targeted pharmaceuticals refer to the ciprofloxacin (CIP) antibiotic and the carbamazepine (CBZ) drug, for which the current water treatment process seem to be less efficient, making them appear in exceedingly high concentrations, even in tap water. The study reveals first the progress made for improving the mechanical stability and resilience to water disintegration, as a function of pH, of chitosan-based cryostructures. Further on, a retention study shows that both pharmaceuticals are retained with high efficiency (up to 85.94% CIP and 86.38% CBZ) from diluted aqueous solutions.

Recent Advances in Membranes Used for Nanofiltration to Remove Heavy Metals from Wastewater: A Review.

The presence of heavy metal ions in polluted wastewater represents a serious threat to human health, making proper disposal extremely important. The utilization of nanofiltration (NF) membranes has emerged as one of the most effective methods of heavy metal ion removal from wastewater due to their efficient operation, adaptable design, and affordability. NF membranes created from advanced materials are becoming increasingly popular due to their ability to depollute wastewater in a variety of circumstances. Tailoring the NF membrane's properties to efficiently remove heavy metal ions from wastewater, interfacial polymerization, and grafting techniques, along with the addition of nano-fillers, have proven to be the most effective modification methods. This paper presents a review of the modification processes and NF membrane performances for the removal of heavy metals from wastewater, as well as the application of these membranes for heavy metal ion wastewater treatment. Very high treatment efficiencies, such as 99.90%, have been achieved using membranes composed of polyvinyl amine (PVAM) and glutaraldehyde (GA) for Cr3+ removal from wastewater. However, nanofiltration membranes have certain drawbacks, such as fouling of the NF membrane. Repeated cleaning of the membrane influences its lifetime.

A Comparative Study of the Impact of the Bleaching Method on the Production and Characterization of Cotton-Origin Nanocrystalline Cellulose by Acid and Enzymatic Hydrolysis.

Due to environmental concerns, as well as its exceptional physical and mechanical capabilities, biodegradability, and optical and barrier qualities, nanocellulose has drawn a lot of interest as a source of reinforcing materials that are nanometer sized. This article focuses on how to manufacture cellulose nanomaterials from cotton by using different types of acids such as H2SO4 and HCI in different concentrations and in the presence of enzymes such as cellulase and xylanase. Two different types of bleaching methods were used before acid and enzyme hydrolysis. In the first method, cellulose was extracted by bleaching the cotton with H2O2. In the second method, NaOCl was utilized. For both methods, different concentrations of acids and enzymes were used to isolate nanocellulose materials, cellulose nanocrystals (CNC), and cellulose nanofibrils (CNF) at different temperatures. All obtained nanocellulose materials were analyzed through different techniques such as FT-IR, Zeta potentials, DLS, Raman spectroscopy, TGA, DSC, XRD, and SEM. The characteristic signals related to cellulose nanocrystals (CNC) were confirmed with the aid of Raman and FT-IR spectroscopy. According to the XRD results, the samples' crystallinity percentages range from 54.1% to 63.2%. The SEM image showed that long fibers break down into small fibers and needle-like features are seen on the surface of the fibers. Using different types of bleaching has no significant effect on the thermal stability of samples. The results demonstrate a successful method for synthesizing cellulose nanofibrils (CNF) from cotton through enzymatic hydrolysis, but the results also demonstrated that the choice of bleaching method has a significant impact on the hydrodynamic properties and crystallinity of both CNC and CNF samples.

Electrospun/3D-Printed Bicomponent Scaffold Co-Loaded with a Prodrug and a Drug with Antibacterial and Immunomodulatory Properties.

This work reports the construction of a bicomponent scaffold co-loaded with both a prodrug and a drug (BiFp@Ht) as an efficient platform for wound dressing, by combining the electrospinning and 3D-printing technologies. The outer component consisted of a chitosan/polyethylene oxide-electrospun membrane loaded with the indomethacin-polyethylene glycol-indomethacin prodrug (Fp) and served as a support for printing the inner component, a gelatin methacryloyl/sodium alginate hydrogel loaded with tetracycline hydrochloride (Ht). The different architectural characteristics of the electrospun and 3D-printed layers were very well highlighted in a morphological analysis performed by Scanning Electron Microscopy (SEM). In vitro release profile studies demonstrated that both Fp and Ht layers were capable to release the loaded therapeutics in a controlled and sustained manner. According to a quantitative in vitro biological assessment, the bicomponent BiFp@Ht scaffold showed a good biocompatibility and no cytotoxic effect on HeLa cell cultures, while the highest proliferation level was noted in the case of HeLa cells seeded onto an Fp nanofibrous membrane. Furthermore, the BiFp@Ht scaffold presented an excellent antimicrobial activity against the E. coli and S. aureus bacterial strains, along with promising anti-inflammatory and proangiogenic activities, proving its potential to be used for wound dressing.

Phytoremediation of Wastewater Containing Lead and Manganese Ions Using Algae.

Heavy metal pollution of water from industrial discharge is a major problem worldwide. Thus, the quality of the environment and human health are severely affected. Various conventional technologies have been applied for water treatment, but these can be expensive, especially for industrial water treatment, and may have limited treatment efficiencies. Phytoremediation is a method that is successfully applied to remove metal ions from wastewater. In addition to the high efficiency of the depollution treatment, this method has the advantages of a low cost of the operation and the existence of many plants that can be used. This article presents the results of using algae (Sargassum fusiforme and Enteromorpha prolifera) to treat water containing manganese and lead ions. It was observed that maximum efficiencies for wastewater treatment were obtained when was used the algae Enteromorpha prolifera for a 600 min contact time period. The highest wastewater treatment efficiency obtained using Sargassum fusiforme was 99.46%.

Hybrid Cryogels with Superabsorbent Properties as Promising Materials for Penicillin G Retention.

This present study describes the investigation of new promising hybrid cryogels able to retain high amounts of antibiotics, specifically penicillin G, using chitosan or chitosan-biocellulose blends along with a naturally occurring clay, i.e., kaolin. In order to evaluate and optimize the stability of cryogels, three types of chitosan were used in this study, as follows: (i) commercial chitosan; (ii) chitosan prepared in the laboratory from commercial chitin; and (iii) chitosan prepared in the laboratory from shrimp shells. Biocellulose and kaolin, previously functionalized with an organosilane, were also investigated in terms of their potential to improve the stability of cryogels during prolonged submergence under water. The organophilization and incorporation of the clay into the polymer matrix were confirmed by different characterization techniques (such as FTIR, TGA, SEM), while their stability in time underwater was investigated by swelling measurements. As final proof of their superabsorbent behavior, the cryogels were tested for antibiotic adsorption in batch experiments, in which case cryogels based on chitosan extracted from shrimp shells seem to exhibit excellent adsorption properties for penicillin G.