Environmental factors modify silver nanoparticles ecotoxicity in Chydorus eurynotus (Cladocera).

Silver nanoparticles (AgNPs) are among the most produced nanomaterials in the world and are incorporated into several products due to their biocide and physicochemical properties. Since freshwater bodies are AgNPs main final sink, several consequences for biota are expected to occur. With the hypothesis that AgNPs can interact with environmental factors, we analyzed their ecotoxicity in combination with humic acids and algae. In addition to the specific AgNPs behavior in the media, we analyzed the mortality, growth, and phototactic behavior of Chydorus eurynotus (Cladocera) as response variables. While algae promoted Ag+ release, humic acids reduced it by adsorption, and their combination resulted in an intermediated Ag+ release. AgNPs affected C. eurynotus survival and growth, but algae and humic acids reduced AgNPs lethality, especially when combined. The humic acids mitigated AgNP effects in C. eurynotus growth, and both factors improved its phototactic behavior. It is essential to deepen the study of the isolated and combined influences of environmental factors on the ecotoxicity of nanoparticles to achieve accurate predictions under realistic exposure scenarios.

4D Printing: The Development of Responsive Materials Using 3D-Printing Technology.

Additive manufacturing, widely known as 3D printing, has revolutionized the production of biomaterials. While conventional 3D-printed structures are perceived as static, 4D printing introduces the ability to fabricate materials capable of self-transforming their configuration or function over time in response to external stimuli such as temperature, light, or electric field. This transformative technology has garnered significant attention in the field of biomedical engineering due to its potential to address limitations associated with traditional therapies. Here, we delve into an in-depth review of 4D-printing systems, exploring their diverse biomedical applications and meticulously evaluating their advantages and disadvantages. We emphasize the novelty of this review paper by highlighting the latest advancements and emerging trends in 4D-printing technology, particularly in the context of biomedical applications.

Development and Validation of a Simple, Fast, and Accessible HPLC-UV Method for Cannabinoids Determination in Cannabis sativa L. Extracts and Medicinal Oils.

INTRODUCTION: Cannabis sativa L. is a well-recognized medicinal plant. Cannabis regulations in Argentina are insufficient to solve the problem of patient access to full-spectrum cannabis-based products. So, the market of artisanal products with unknown quality and dosage of cannabinoids is increasing, and so is the local demand and need for analyzing these products. However, much of the latest validated methodologies for cannabinoid quantification include expensive instrumentation that is not always available in laboratories of health institutions in Argentina. METHODS: The aim of this work was to develop and validate a simple and rapid HPLC-UV method for the identification and quantification of principal cannabinoids in cannabis resins, inflorescences, and medicinal oils using standard HPLC equipment. The cannabinoids selected for validation were cannabidiol acid (CBDA), cannabigerol (CBG), cannabidiol (CBD), cannabinol (CBN), delta-9-tetrahydrocannabinol (Δ9-THC), cannabichromene (CBC), and tetrahydrocannabinol acid (THCA). A method for the simultaneous identification and quantification of these 7 main cannabinoids was developed and then validated. Some data parameters were comparable to other reports with more sophisticated analytical instruments for the analysis of cannabis. The assessed limits of detection and the limits of quantitation ranged from 0.9 to 3.66 µg/mL and 2.78 to 11.09 µg/mL, respectively. The concentration-response relationship of the method indicated a linear relationship between the concentration and peak area with R2 values of > 0.99 for all 7 cannabinoids. RESULTS: The relative standard deviation (RSD%) varied from 2.34 to 4.82 for intraday repeatability and from 1.16 to 3.15 for interday repeatability. The percentage of recovery values was between 94 to 115% (resins) and 80 to 103% (inflorescence extract). The cannabis industry is growing rapidly, and there is a need for reliable testing methods to ensure the safety and efficacy of cannabis products. In addition, current methods for cannabinoid analysis are often time-consuming and expensive, while the HPLC-UV method herein reported is a simple, rapid, accurate, and cost-effective alternative for the analysis of cannabinoids in cannabis resins, inflorescences, and medicinal oils. CONCLUSION: This method will be proposed to be included in the Cannabis sativa L. monograph of the Argentine Pharmacopoeia.

Ecotoxicity of nanosilver on cladocerans and the role of algae provision.

Silver nanoparticles (AgNPs) are applied in diverse industries due to their biocide and physicochemical properties; therefore, they can be released into aquatic systems, interact with environmental factors, and ultimately exert adverse effects on the biota. We analyzed AgNPs effects on Ceriodaphnia reticulata (Cladocera) through mortality and life-history traits, considering the influence of food (Tetradesmus obliquus, Chlorophyceae) presence and concentration. C. reticulata was exposed to AgNPs in acute (absence and two algae concentrations plus five AgNPs treatments) and chronic assays (two algae concentrations plus three AgNPs treatments). AgNPs did not affect algae flocculation but increased Ag+ release, being these ions less toxic than AgNPs (as proved by the exposure to AgNO3). A reduction in AgNPs acute toxicity was observed when algae concentration increased. Acute AgNP exposure decreased C. reticulata body size and heart rate. The chronic AgNP exposure reduced C. reticulata molt number, growth, heart rate, and neonate size:number ratio, being these effects mitigated at the highest algae concentration. Increases in relative size and number of neonates were observed in AgNP treatments suggesting energy trade off. The increased Ag+ release with food presence suggests that the AgNP-algae interaction might be responsible of the decreased toxicity. Although algae reduced AgNP toxicity, they still exerted adverse effects on C. reticulata below predicted environmental concentrations. Since algae presence reduces AgNP effects but increases Ag+ release, studies should be continued to provide evidence on their toxicity to other organisms.

Green Synthesis: A Land of Complex Nanostructures.

The green synthesis of nanomaterials is nowadays gaining great attention owing to several beneficial aspects in terms of the low toxicity of reagents and by-products, low damage to the health and the environment, sustainability of energy savings and rational use of natural resources. The intrinsic complexity offered by the biological sources (plants, microorganisms, animal products) and the conditions applied in the synthetic procedures forms various nanomaterials with different sizes, morphologies and surface properties that strongly determine their functionality and applications. A deep understanding of the role of biological components, the mechanism of nanostructure formation and growth, and the effects of green synthesis conditions is of paramount importance to achieving the desired nanomaterial for the required application. In this context, this review aims to provide an overview of the structural and functional complexity of nanomaterials achieved by using green synthesis procedures, with a special focus on the role of biological sources and parameters in controlling the complexity and benefit of nanomaterial applications.

Entourage Effect and Analytical Chemistry: Chromatography as a Tool in the Analysis of the Secondary Metabolism of Cannabis sativa L.

Cannabis sativa L. has been used as medicine for thousands of years. Since the early identification of tetrahydrocannabinol (THC) in 1960, pharmacological activities were attributed to a group of unique structures named cannabinoids. For decades, research and development were applied to determine different cannabinoids and their medicinal properties. Nowadays there is evidence that the therapeutic benefits of the plant are based on the synergy of cannabinoids and other secondary metabolites such as terpenes and flavonoids. Differences between the medical performance of isolated compounds like cannabidiol (CBD) or THC and full-spectrum plant extracts are notable. Indeed, the superiority of the last one is provoked by the synergy between various different compounds. This improved medicinal effect is called the entourage effect. Chromatography has become the method of choice for the determination of cannabinoids, terpenes, and flavonoids, so it represents an excellent tool for a proper characterization of the plant and plant derived products. The objective of characterization relies not only in analyzing the fingerprint of cannabis, but also to identify different chemotypes for medical purposes. To understand the contributions of each natural product to this "entourage effect", this review presents an in-depth analysis of the utilization of High-performance liquid chromatography (HPLC), Gas chromatography (GC) and other methods for the analysis of phytocomponents of Cannabis sativa L. In this sense, a representative number of examples and advances made in the field together with limitations and future needs are provided. It can be concluded that standardized protocols and quality control policies and procedures are necessary for the comprehensive analysis of cannabis extracts and derivatives.

Design of a New 3D Gelatin-Alginate Scaffold Loaded with Cannabis sativa Oil.

There is an increasing medical need for the development of new materials that could replace damaged organs, improve healing of critical wounds or provide the environment required for the formation of a new healthy tissue. The three-dimensional (3D) printing approach has emerged to overcome several of the major deficiencies of tissue engineering. The use of Cannabis sativa as a therapy for some diseases has spread throughout the world thanks to its benefits for patients. In this work, we developed a bioink made with gelatin and alginate that was able to be printed using an extrusion 3D bioprinter. The scaffolds obtained were lyophilized, characterized and the swelling was assessed. In addition, the scaffolds were loaded with Cannabis sativa oil extract. The presence of the extract provided antimicrobial and antioxidant activity to the 3D scaffolds. Altogether, our results suggest that the new biocompatible material printed with 3D technology and with the addition of Cannabis sativa oil could become an attractive alternative to common treatments of soft-tissue infections and wound repair.

The 3D Bioprinted Scaffolds for Wound Healing.

Skin tissue engineering and regeneration aim at repairing defective skin injuries and progress in wound healing. Until now, even though several developments are made in this field, it is still challenging to face the complexity of the tissue with current methods of fabrication. In this review, short, state-of-the-art on developments made in skin tissue engineering using 3D bioprinting as a new tool are described. The current bioprinting methods and a summary of bioink formulations, parameters, and properties are discussed. Finally, a representative number of examples and advances made in the field together with limitations and future needs are provided.

Development of 3D-Printed Collagen Scaffolds with In-Situ Synthesis of Silver Nanoparticles.

UV-irradiation method has grown as an alternative approach to in situ synthetize silver nanoparticles (AgNPs) for avoiding the use of toxic reducing agents. In this work, an antimicrobial material by in situ synthesizing AgNPs within 3D-printed collagen-based scaffolds (Col-Ag) was developed. By modifying the concentration of AgNO3 (0.05 and 0.1 M) and UV irradiation time (2 h, 4 h, and 6 h), the morphology and size of the in situ prepared AgNPs could be controlled. As a result, star-like silver particles of around 23 ± 4 µm and spherical AgNPs of 220 ± 42 nm were obtained for Ag 0.05 M, while for Ag 0.1 M cubic particles from 0.3 to 1.0 µm and round silver precipitates of 3.0 ± 0.4 µm were formed in the surface of the scaffolds at different UV irradiation times. However, inside the material AgNPs of 10-28 nm were obtained. The DSC thermal analysis showed that a higher concentration of Ag stabilizes the 3D-printed collagen-based scaffolds, while a longer UV irradiation interval produces a decrease in the denaturation temperature of collagen. The enzymatic degradation assay also revealed that the in situ formed AgNPs act as stabilizing and reinforcement agent which also improve the swelling capacity of collagen-based material. Finally, antimicrobial activity of Col-Ag was studied, showing high bactericidal efficiency against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. These results showed that the UV irradiation method was really attractive to modulate the size and shape of in situ synthesized AgNPs to develop antimicrobial 3D-printed collagen scaffolds with different thermal, swelling and degradation properties.

Collagen Hydrogels Loaded with Silver Nanoparticles and Cannabis Sativa Oil.

Wounds represent a major healthcare problem especially in hospital-associated infections where multi-drug resistant strains are often involved. Nowadays, biomaterials with therapeutic molecules play an active role in wound healing and infection prevention. In this work, the development of collagen hydrogels loaded with silver nanoparticles and Cannabis sativa oil extract is described. The presence of the silver nanoparticles gives interesting feature to the biomaterial such as improved mechanical properties or resistance to collagenase degradation but most important is the long-lasting antimicrobial effect. Cannabis sativa oil, which is known for its anti-inflammatory and analgesic effects, possesses antioxidant activity and successfully improved the biocompatibility and also enhances the antimicrobial activity of the nanocomposite. Altogether, these results suggest that this novel nanocomposite biomaterial is a promising alternative to common treatments of wound infections and wound healing.

Recent Advances in Micro-Electro-Mechanical Devices for Controlled Drug Release Applications.

In recent years, controlled release of drugs has posed numerous challenges with the aim of optimizing parameters such as the release of the suitable quantity of drugs in the right site at the right time with the least invasiveness and the greatest possible automation. Some of the factors that challenge conventional drug release include long-term treatments, narrow therapeutic windows, complex dosing schedules, combined therapies, individual dosing regimens, and labile active substance administration. In this sense, the emergence of micro-devices that combine mechanical and electrical components, so called micro-electro-mechanical systems (MEMS) can offer solutions to these drawbacks. These devices can be fabricated using biocompatible materials, with great uniformity and reproducibility, similar to integrated circuits. They can be aseptically manufactured and hermetically sealed, while having mobile components that enable physical or analytical functions together with electrical components. In this review we present recent advances in the generation of MEMS drug delivery devices, in which various micro and nanometric structures such as contacts, connections, channels, reservoirs, pumps, valves, needles, and/or membranes can be included in their design and manufacture. Implantable single and multiple reservoir-based and transdermal-based MEMS devices are discussed in terms of fundamental mechanisms, fabrication, performance, and drug release applications.

Silicified collagen materials: Modulation of the in vitro and in vivo response.

Collagen derived materials offer distinct advantages over synthetic polymers, considering their natural inherited biocompatibility and mechanical properties. However, because of the extraction procedure, the latter frequently need to be enhanced through the use of different crosslinking methods. Aldehydes are often used for the stabilization of biomaterials but the introduction of crosslinkers slightly alters the protein's surface reactivity hence calling for new biocompatibility studies. At the same time, silicate modification of natural polymers has gained interest within the biomaterials field for their strengthening potential and ease of manipulation, giving rise to different surfaces and bulk materials. In the present work, collagen gels modified with glutaraldehyde (ColGA) or glutaraldehyde and an aminosilane (ColGASi) were evaluated in vitro and in vivo with the aim to obtain biomaterials for wound dressings. The results obtained were compared to those derived from unmodified collagen matrices (Col). In vitro assays focused on the interaction of the materials with elements present in the human blood whereas in vivo assays evaluated their ability to support cell proliferation and angiogenesis for a period of 30 days in a rodent model. Col gels induced an increase in platelet aggregation while ColGA gels decreased it. On the other hand, ColGASi had no effect on platelet aggregation but induced IL-1ß and nitric oxide platelet secretion. All gels induced lower IL-6 levels in PMN cells cultures when compared to controls. Col and ColGA gels decreased IL-1ß concentration whereas ColGASi induced high expression of TGF-ß in PMN cells. All gels decreased nitric oxide secretion but Col and ColGA gels increased IL-1ß production by monocytes. Definitely, all gels induced an anti and pro-inflammatory profile depending on the cell type with which they interact. In vivo, an increased cellular infiltration was observed along with new blood vessel formation in those matrices containing silicified collagen, while glutaraldehyde fixed collagen induced a foreign body reaction and appeared surrounded by a fibrous capsule after 30 days of subcutaneous implantation. Overall, the results obtained show that the silicification of collagen has advantages not only through the enhancement of its mechanical properties but also through the stimulation of the integration of the material with the surrounding tissue.

Copper-induced cell death and the protective role of glutathione: the implication of impaired protein folding rather than oxidative stress.

Copper (Cu) is a bioelement essential for a myriad of enzymatic reactions, which when present in high concentration leads to cytotoxicity. Whereas Cu toxicity is usually assumed to originate from the metal's ability to enhance lipid peroxidation, the role of oxidative stress has remained uncertain since no antioxidant therapy has ever been effective. Here we show that Cu overload induces cell death independently of the metal's ability to oxidize the intracellular milieu. In fact, cells neither lose control of their thiol homeostasis until briefly before the onset of cell death, nor trigger a consistent antioxidant response. As expected, glutathione (GSH) protects the cell from Cu-mediated cytotoxicity but, surprisingly, fully independent of its reactive thiol. Moreover, the oxidation state of extracellular Cu is irrelevant as cells accumulate the metal as cuprous ions. We provide evidence that cell death is driven by the interaction of cuprous ions with proteins which impairs protein folding and promotes aggregation. Consequently, cells mostly react to Cu by mounting a heat shock response and trying to restore protein homeostasis. The protective role of GSH is based on the binding of cuprous ions, thus preventing the metal interaction with proteins. Due to the high intracellular content of GSH, it is depleted near the Cu entry site, and hence Cu can interact with proteins and cause aggregation and cytotoxicity immediately below the plasma membrane.

Development of pH-responsive biopolymer-silica composites loaded with Larrea divaricata Cav. extract with antioxidant activity.

A detailed study of biomaterials is mandatory to comprehend their feasible biomedical applications in terms of drug delivery and tissue regeneration. Particularly, mucoadhesive biopolymers such as chitosan (chi) and carboxymethylcellulose (CMC) have become interesting biomaterials regards to their biocompatibility and non-toxicity for oral mucosal drug delivery. In this work, pH-responsive biopolymer-silica composites (Chi-SiO2, Chi-CMC-SiO2) were developed. These two types of composites presented a different swelling behavior due to the environmental pH. Moreover, the nanocomposites were loaded with aqueous Larrea divaricata Cav. extract (Ld), a South American plant which presents antioxidant properties suitable for the treatment of gingivoperiodontal diseases. Chi-CMC-SiO2 composites showed the highest incorporation and reached the 100% of extract release in almost 4 days while they preserved their antioxidant properties. In this study, thermal and swelling behavior were pointed out to show the distinct water-composite interaction and therefore to evaluate their mucoadhesivity. Furthermore, a cytotoxicity test with 3T3 fibroblasts was assessed, showing that in both composites the addition of Larrea divaricata Cav. extract increased fibroblast proliferation. Lastly, preliminary in vitro studies were performed with simulated body fluids. Indeed, SEM-EDS analysis indicated that only chi-SiO2 composite may provide an environment for possible biomineralization while the addition of CMC to the composites discouraged calcium accumulation. In conclusion, the development of bioactive composites could promote the regeneration of periodontal tissue damaged throughout periodontal disease and the presence of silica nanoparticles could provide an environment for biomineralization.

Development and evaluation of thymol-chitosan hydrogels with antimicrobial-antioxidant activity for oral local delivery.

Nowadays, the research of innovative drug delivery devices is focused on the design of multiple drug delivery systems, the prevention of drug side effects and the reduction of dosing intervals. Particularly, new mucosal delivery systems for antimicrobials, antioxidants and anti-inflammatory drugs has a growing development, regards to the avoidance of side effects, easy administration and a suitable drug concentration in the mucosa. In this work, chitosan hydrogels are evaluated as a biodegradable scaffold and as a bioactive agent carrier of an antioxidant-antimicrobial compound called thymol. Throughout the study, swelling behavior, viscoelastic properties and thermal analysis are highlighted to present its advantages for a biomedical application. Furthermore, the in vitro results obtained indicate that thymol-chitosan hydrogels are biocompatible when exposed to [3T3] fibroblasts, exhibit antimicrobial activity against Staphylococcus aureus and Streptococcus mutans for 72h and antioxidant activity for 24h. These are desirable properties for a mucosal delivery system for an antimicrobial-antioxidant dual therapy for periodontal disease.

Nanoparticles and capillary electrophoresis: A marriage with environmental impact.

The impact of nanomaterials in the environment and human health is a cause of big concern and even though intensive studies are currently being carried out, there is still a lot to elucidate. The development of validated methods for the characterization and quantification of nanomaterials and their impact on the environment should be encouraged to achieve a proper, safe, and sustainable use of nanoparticles (NPs). Recently, CE emerged as a well-adapted technique for the analysis of environmental samples. This review presents the application of NPs together with CE systems for environmental pollutants analysis, as well as the application of CE techniques for the analysis of various types of NPs.

Advances in collagen, chitosan and silica biomaterials for oral tissue regeneration: from basics to clinical trials.

Different materials have distinct surface and bulk characteristics; each of them potentially useful for the treatment of a particular wound or disease. By reviewing those materials that have reached a clinical stage the reader will have a broad panorama of the possibilities a particular material can offer, regarding its ability to support fast tissue regeneration. This review covers the most recent advances made towards the development of biomaterials aimed to support regenerative processes. Indeed, we highlight key examples, from basic research to clinical trials, of biomaterials for a specific biomedical application. In this context, the focus is made on collagen, chitosan and silica which are key representatives of a protein, a polysaccharide and an inorganic material usually employed as biomaterials. Particularly, this review article presents an overview of their potential therapeutics in the treatment of disorders within the oral mucosa and tooth supporting tissues. Finally, the importance of in vivo and in vitro studies, clinical evidence studies, systematic reviews and meta-analyses as an adequate guidance for biomaterial design and development is highlighted.

Antibiotic-loaded silica nanoparticle-collagen composite hydrogels with prolonged antimicrobial activity for wound infection prevention.

Silica-collagen type I nanocomposite hydrogels are evaluated as medicated dressings to prevent infection in chronic wounds. Two antibiotics, gentamicin and rifamycin, are encapsulated in a single step within plain silica nanoparticles. Their antimicrobial efficiency against Pseudomonas aeruginosa and Staphylococcus aureus is assessed. Gentamycin-loaded 500 nm particles can be immobilized at high silica dose in concentrated collagen hydrogels without modifying their fibrillar structure or impacting on their rheological behavior and increases their proteolytic stability. Gentamicin release from the nanocomposites is sustained over 7 days, offering an unparalleled prolonged antibacterial activity. Particle immobilization also decreases their cytotoxicity towards surface-seeded fibroblast cells. Rifamycin-loaded 100 nm particles significantly alter the collagen hydrogel structure at high silica doses. The thus-obtained nanocomposites show no antibacterial efficiency, due to strong adsorption of rifamycin on collagen fibers. The complex interplay of interactions between drugs, silica and collagen is a key factor regulating the properties of these composite hydrogels as antibiotic-delivering biological dressings and must be taken into account for future extension to other wound healing agents.

Preparation of submicrometer monodispersed magnetic silica particles using a novel water in oil microemulsion: properties and application for enzyme immobilization.

The synthesis of monodispersed magnetic silica nanoparticles (MSN) is described using a water-in-oil reverse microemulsion system that does not require the use of co-surfactants. Sodium silicate, Tween 20 as a neutral surfactant and 1-butanol as the organic phase were used. There are several advantages of the proposed method including a saturation magnetization value of 10 emu/g for the particles obtained, uniformity of size and that they are easily functionalized to bind urease covalently. Moreover, the intra-day, inter-day and long-term stability results confirm that the procedure was successful and the enzyme-linked MSNs were stable over repeated uses and storage retaining more than 75% activity after 4 months.