Sustainable and Biomimetic Methodology for Extraction of High-Value-Added Compounds in Almond Hulls.

Almond trees are the most cultivated nut tree in the world. The production of almonds generates large amounts of by-products, much of which goes unused. Herein, this study aimed to develop a green chemistry approach to identify and extract potentially valuable compounds from almond by-products. Initially, a screening was performed with 10 different Natural Deep Eutectic Solvents (NADESs). The mixture lactic acid/glycerol, with a molar ratio 1:1 (1:50 plant material to NADES (w/v) with 20% v/v of water) was identified as the best extraction solvent for catechin, caffeoylquinic acid, and condensed tannins in almond hulls. Subsequently, a method was optimized by a Design of Experiment (DoE) protocol using a miniaturized extraction technique, Microwave-Assisted Extraction (MAE), in conjunction with the chosen NADESs. The optimal conditions were found to be 70 °C with 15 min irradiation time. The optimal extraction conditions determined by the DoE were confirmed experimentally and compared to methods already established in the literature. With these conditions, the extraction of metabolites was 2.4 times higher, according to the increase in total peak area, than the established literature methods used. Additionally, by applying the multiparameter Analytical Greenness Metric (AGREE) and Green Analytical Process Index (GAPI) metrics, it was possible to conclude that the developed method was greener than the established literature methods as it includes various principles of green analytical chemistry.

Biomimetic Chemical Reactions with Natural Products Using Metalloporphyrins and Salen Complexes as Catalysts: A Brief Review.

The cytochrome P450 is a superfamily of hemoproteins mainly present in the liver and are versatile biocatalysts. They participate in the primary metabolism and biosynthesis of various secondary metabolites. Chemical catalysts are utilized to replicate the activities of enzymes. Metalloporphyrins and Salen complexes can contribute to the products' characterization and elucidate biotransformation processes, which are investigated during pre-clinical trials. These catalysts also help discover biologically active compounds and get better yields of products of industrial interest. This review aims to investigate which natural product classes are being investigated by biomimetic chemical models and the functionalities applied in the use of these catalysts. A limited number of studies were observed, with terpenes and alkaloids being the most investigated natural product classes. The research also revealed that Metalloporphyrins are still the most popular in the studies, and the identity and yield of the products obtained depend on the reaction system conditions.

Microfabrication-based engineering of biomimetic dentin-like constructs to simulate dental aging.

Human dentin is a highly organized dental tissue displaying a complex microarchitecture consisting of micrometer-sized tubules encased in a mineralized type-I collagen matrix. As such, it serves as an important substrate for the adhesion of microbial colonizers and oral biofilm formation in the context of dental caries disease, including root caries in the elderly. Despite this issue, there remains a current lack of effective biomimetic in vitro dentin models that facilitate the study of oral microbial adhesion by considering the surface architecture at the micro- and nanoscales. Therefore, the aim of this study was to develop a novel in vitro microfabricated biomimetic dentin surface that simulates the complex surface microarchitecture of exposed dentin. For this, a combination of soft lithography microfabrication and biomaterial science approaches were employed to construct a micropitted PDMS substrate functionalized with mineralized type-I collagen. These dentin analogs were subsequently glycated with methylglyoxal (MGO) to simulate dentin matrix aging in vitro and analyzed utilizing an interdisciplinary array of techniques including atomic force microscopy (AFM), elemental analysis, and electron microscopy. AFM force-mapping demonstrated that the nanomechanical properties of the biomimetic constructs were within the expected biological parameters, and that mineralization was mostly predominated by hydroxyapatite deposition. Finally, dual-species biofilms of Streptococcus mutans and Candida albicans were grown and characterized on the biofunctionalized PDMS microchips, demonstrating biofilm-specific morphologic characteristics and confirming the suitability of this model for the study of early biofilm formation under controlled conditions. Overall, we expect that this novel biomimetic dentin model could serve as an in vitro platform to study oral biofilm formation or dentin-biomaterial bonding in the laboratory without the need for animal or human tooth samples in the future.

Sobrevivência em fadiga de coroas bioinspiradas bilaminadas: estudo in vitro / Fatigue survival rate of bioinspired bilaminar crowns: in vitro study

O objetivo deste estudo foi avaliar o comportamento biomecânico através da resistência à fadiga e análise por elementos finitos de coroas bioinspiradas bilaminadas com infraestruturas modificadas na superfície vestibular (Estudo A) e utilizando diferentes materiais cerâmicos com módulos elásticos distintos (Estudo B). Para isso, foram confeccionados 90 preparos para coroa total em resina epóxi G10, sobre os quais foram preparadas coroas bioinspiradas de acordo com os seguintes grupos: Estudo A - IC (infraestrutura convencional), IME (infraestrutura modificada estratificada) e IMC (infraestrutura modificada cimentada), todas confeccionadas em dissilicato de lítio (infraestrutura) + porcelana (recobrimento); Estudo B ­ DL+LEU (dissilicato de lítio + leucita), LEU+DL (leucita + dissilicato de lítio), CH+DL (cerâmica híbrida + dissilicato de lítio) e CH+LEU (cerâmica híbrida + leucita). Para o Estudo A, todas as infraestruturas foram usinadas; os recobrimentos dos grupos IC e IME foram confeccionados através da estratificação, e os recobrimentos do grupo IMC foram usinados. Já para o Estudo B, todas as peças foram usinadas, de acordo com o material cerâmico de cada grupo. Em seguida, foi realizada a cimentação adesiva dos recobrimentos sobre as infraestruturas (a depender do grupo) e das coroas sobre os preparos utilizando cimento resinoso fotopolimerizável (Variolink Esthetic LC). Após a cimentação, os espécimes foram submetidos ao teste de fadiga cíclica (10.000 ciclos, 20Hz), e como desfecho foram considerados dois eventos, em que o primeiro foi a ocorrência de trinca e/ou lascamento (evento 1) e o segundo foi a falha catastrófica do conjunto (evento 2). Os valores de carga e número de ciclos para falha em que foram observados os eventos 1 e 2 foram utilizados para realizar a análise de sobrevivência de acordo com Kaplan-Meier e Log-Rank (Mantel-Cox; 95%). As marcas de fratura e o modo de falha das coroas foram avaliados e classificados por estereomicroscópio óptico e microscópio eletrônico de varredura. Por fim, foi realizada análise por elementos finitos (FEA) para ambos os estudos, a fim de avaliar a distribuição de tensões sobre as coroas e interface adesiva. Para o Estudo A, os resultados do teste de fadiga mostraram que, considerando o evento 1 (trinca/lascamento), os grupos IC e IMC apresentaram médias de carga fadiga estatisticamente significantes entre si (733,33 N e 913,33 N, respectivamente), enquanto o grupo IME apresentou média superior (1.020 N). O mesmo foi observado para o número de ciclos em fadiga para todos os grupos. Ao considerar o evento 2 (falha catastrófica), os três grupos apresentaram médias estatisticamente semelhantes entre si (~1.028 N). Os resultados de FEA mostraram que o grupo IC concentrou maior tensão de tração do que os grupos IME e IMC. Para o Estudo B, no teste de fadiga, o grupo DL+LEU apresentou a maior média de resistência à fadiga (evento 1: 913,33 N e evento 2: 1033,33 N), enquanto todas as outras combinações de materiais cerâmicos analisadas foram estatisticamente semelhantes entre si, considerando carga e número de ciclos. Com relação ao FEA, os grupos com cerâmica híbrida (CH+DL e CH+LEU) apresentaram menores picos de concentração de tensão na infraestrutura do que os grupos com cerâmicas vítreas (DL+LEU e LEU+DL), porém, em contrapartida, concentraram maior tensão na interface adesiva. Com isso, conclui-se que a utilização da infraestrutura modificada é uma alternativa viável e promissora para tratamentos reabilitadores, apresentando sobrevivência em fadiga e distribuição de tensões satisfatórias. Além disso, a combinação entre uma infraestrutura de dissilicato de lítio e recobrimento de cerâmica a base de leucita corresponde a melhor abordagem considerando a infraestrutura modificada.(AU)

The objective of this study was to evaluate the biomechanical behavior through fatigue resistance and finite element analysis of bilaminar bioinspired crowns with modified infrastructures on the buccal surface (Study A) and using different ceramic materials with different elastic moduli (Study B). For this, 90 preparations were made for a full crown in G10 epoxy resin, on which bioinspired crowns were prepared according to the following groups: Study A - CI (conventional infrastructure), SMI (stratified modified infrastructure) and CMI (cemented modified infrastructure ), all made of lithium disilicate (infrastructure) + porcelain (veneer); Study B ­ LD+LEU (lithium disilicate + leucite), LEU+LD (leucite + lithium disilicate), HC+LD (hybrid ceramic + lithium disilicate) and HC+LEU (hybrid ceramic + leucite). For Study A, all infrastructures were machined; the coverings of the CI and SMI groups were made through stratification technique, and the veneers of the SMI group were machined. For Study B, all pieces were machined, according to the ceramic material of each group. Then, the veneers were cemented into their infrastructures (depending on the group) and crowns were cemented into preparations using light-cured resin cement (Variolink Esthetic LC). After cementing, the specimens were subjected to the cyclic fatigue test (10,000 cycles, 20Hz), and as an outcome two events were considered: the occurrence of cracking and/or chipping (event 1) and catastrophic failure (event 2). The load (N) and number of cycles to failure in which events 1 and 2 were observed were used to perform the survival analysis according to Kaplan-Meier and Log-Rank (Mantel- Cox; 95%). The fracture marks and failure mode of the crowns were evaluated and classified by optical stereomicroscope and scanning electron microscope. Finally, finite element analysis (FEA) was performed for both studies in order to evaluate the stress distribution over the crowns and adhesive interface. For Study A, the results of the fatigue test showed that, considering event 1 (cracking/chipping), the CI and CMI groups presented average to failure that were statistically significant compared to each other (733.33 N and 913.33 N, respectively), while the SMI group showed higher averages (1,020 N). Same pattern was observed for the number of cycles under fatigue for both groups. When considering event 2 (catastrophic failure), the three groups presented statistically similar means (~1,028 N). The FEA results showed that the CI group concentrated greater tensile stress than the CMI and SMI groups. For Study B, in the fatigue test, the LC+LEU group presented the highest average fatigue resistance (event 1: 913.33 N and event 2: 1033.33 N), while all other combinations of ceramic materials analyzed were statistically similar to each other, considering load and number of cycles. Regarding FEA, the groups with hybrid ceramics (HC+LC and HC+LEU) showed lower stress concentration peaks in the infrastructure than the groups with glass ceramics (LC+LEU and LEU+LC), however, on the other hand, concentrated greater tension at the adhesive interface. With this, it is concluded that the use of modified infrastructure is a viable and promising alternative for oral rehabilitation treatments, presenting satisfactory fatigue survival and adequate stress distribution. Furthermore, the combination of a lithium disilicate infrastructure and a leucite-based ceramic coating corresponds to the best approach considering the modified infrastructure.(AU)

Annexin A5 stabilizes matrix vesicle-biomimetic lipid membranes: unravelling a new role of annexins in calcification.

Matrix vesicles are a special class of extracellular vesicles thought to actively contribute to both physiologic and pathologic mineralization. Proteomic studies have shown that matrix vesicles possess high amounts of annexin A5, suggesting that the protein might have multiple roles at the sites of calcification. Currently, Annexin A5 is thought to promote the nucleation of apatitic minerals close to the inner leaflet of the matrix vesicles' membrane enriched in phosphatidylserine and Ca2+. Herein, we aimed at unravelling a possible additional role of annexin A5 by investigating the ability of annexin A5 to adsorb on matrix-vesicle biomimetic liposomes and Langmuir monolayers made of dipalmitoylphosphatidylserine (DPPS) and dipalmitoylphosphatidylcholine (DPPC) in the absence and in the presence of Ca2+. Differential scanning calorimetry and dynamic light scattering measurements showed that Ca2+ at concentrations in the 0.5-2.0 mM range induced the aggregation of liposomes probably due to the formation of DPPS-enriched domains. However, annexin A5 avoided the aggregation of liposomes at Ca2+ concentrations lower than 1.0 mM. Surface pressure versus surface area isotherms showed that the adsorption of annexin A5 on the monolayers made of a mixture of DPPC and DPPS led to a reduction in the area of excess compared to the theoretical values, which confirmed that the protein favored attractive interactions among the membrane lipids. The stabilization of the lipid membranes by annexin A5 was also validated by recording the changes with time of the surface pressure. Finally, fluorescence microscopy images of lipid monolayers revealed the formation of spherical lipid-condensed domains that became unshaped and larger in the presence of annexin A5. Our data support the model that annexin A5 in matrix vesicles is recruited at the membrane sites enriched in phosphatidylserine and Ca2+ not only to contribute to the intraluminal mineral formation but also to stabilize the vesicles' membrane and prevent its premature rupture.

Biomineralization of calcium phosphates functionalized with hydroxyapatite-binding peptide.

Functionalization of calcium phosphates with biomimetic peptides is a promising strategy to increase cellular response for bone tissue repair. In this work, biphasic calcium phosphate pellets were functionalized with the hydroxyapatite-binding peptide pVTK by dropping a suspension of the peptide on the pellet surface. The bioactivity tests were performed in vitro by using McCoy culture medium. Cytotoxicity tests were also performed to assess cell viability. The material was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy with field emission gun (FEG-SEM). The results showed that functionalization with the biomimetic peptide was most effective in inducing precipitation of bone-like apatite on the pellets surface, when compared to the control groups (two positive control groups and one negative control group). Cytotoxicity tests showed that all samples are biocompatible but the pellets with peptide showed the highest values of cell viability.

Biomimetic catalysis of nitrite reductase enzyme using copper complexes in chemical and electrochemical reduction of nitrite.

Copper nitrite reductase mimetics were synthesized using three new tridentate ligands sharing the same N,N,N motif of coordination. The ligands were based on L-proline modifications, attaching a pyridine and a triazole to the pyrrolidine ring, and differ by a pendant group (R = phenyl, n-butyl and n-propan-1-ol). All complexes coordinate nitrite, as evidenced by cyclic voltammetry, UV-Vis, FTIR and electron paramagnetic resonance (EPR) spectroscopies. The coordination mode of nitrite was assigned by FTIR and EPR as κ2O chelate mode. Upon acidification, EPR experiments indicated a shift from chelate to monodentate κO mode, and 15N NMR experiments of a Zn2+ analogue, suggested that the related Cu(II) nitrous acid complex may be reasonably stable in solution, but in equilibrium with free HONO under non catalytic conditions. Reduction of nitrite to NO was performed both chemically and electrocatalytically, observing the highest catalytic activities for the complex with n-propan-1-ol as pendant group. These results support the hypothesis that a hydrogen bond moiety in the secondary coordination sphere may aid the protonation step.

Oxidation Products from the Neolignan Licarin A by Biomimetic Reactions and Assessment of in vivo Acute Toxicity.

Licarin A, a dihydrobenzofuranic neolignan presents in several medicinal plants and seeds of nutmeg, exhibits strong activity against protozoans responsible for Chagas disease and leishmaniasis. From biomimetic reactions by metalloporphyrin and Jacobsen catalysts, seven products were determined: four isomeric products yielded by epoxidation from licarin A, besides a new product yielded by a vicinal diol, a benzylic aldehyde, and an unsaturated aldehyde in the structure of the licarin A. The incubation with rat and human liver microsomes partially reproduced the biomimetic reactions by the production of the same epoxidized product of m/z 343 [M + H]+. In vivo acute toxicity assays of licarin A suggested liver toxicity based on biomarker enzymatic changes. However, microscopic analysis of tissues sections did not show any tissue damage as indicative of toxicity after 14 days of exposure. New metabolic pathways of the licarin A were identified after in vitro biomimetic oxidation reaction and in vitro metabolism by rat or human liver microsomes.

Exploring in vitro solubility of lamotrigine in physiologically mimetic conditions to prospect the in vivo dissolution in pediatric population.

Pediatric drugs knowledge still leaves several gaps to be filled, all the while many biopharmaceutic properties applied to adults do not work in pediatrics. The solubility in many cases is extrapolated to pediatrics; however, sometimes it may not represent the real scenario. In this context, the aim of this study was to assess the possibility of the extrapolation of the solubility data assumed for adults to children aged 2-12 years using lamotrigine (LTG) as a model. LTG showed that its solubility is dependent on the pH of the medium, no precipitate formation was seen, and biomimetic media showed a greater capacity to solubilize it. Based on the dose number (D0 ) in adults, the LTG was soluble in acidic pH media and poorly soluble in neutral to basic. Similar behavior was found in conditions which mimic children aged 10-12 years at a dose of 5 and 15 mg/kg. The D0 for 5-year-old children at a dose of 15 mg/kg showed different behaviors between biorelevant and pharmacopeial buffers media. For children aged 2-3 years, LTG appeared to be poorly soluble under both gastric and intestinal conditions. Solubility was dependent on the volume of fluid calculated for each age group, and this may impact the development of better pharmaceutical formulations for this population, better pharmacokinetic predictions in tools as PBPK, and physiologically-based biopharmaceutics modeling, greater accuracy in the justifications for biowaiver, and many other possibilities.

Collagen/κ-Carrageenan-Based Scaffolds as Biomimetic Constructs for In Vitro Bone Mineralization Studies.

Tissue engineering offers attractive strategies to develop three-dimensional scaffolds mimicking the complex hierarchical structure of the native bone. The bone is formed by cells incorporated in a molecularly organized extracellular matrix made of an inorganic phase, called biological apatite, and an organic phase mainly made of collagen and noncollagenous macromolecules. Although many strategies have been developed to replicate the complexity of bone at the nanoscale in vitro, a critical challenge has been to control the orchestrated process of mineralization promoted by bone cells in vivo and replicate the anatomical and biological properties of native bone. In this study, we used type I collagen to fabricate mineralized scaffolds mimicking the microenvironment of the native bone. The sulfated polysaccharide κ-carrageenan was added to the scaffolds to fulfill the role of noncollagenous macromolecules in the organization and mineralization of the bone matrix and cell adhesion. Scanning electron microscopy images of the surface of the collagen/κ-carrageenan scaffolds showed the presence of a dense and uniform network of intertwined fibrils, while images of the scaffolds' lateral sides showed the presence of collagen fibrils with a parallel alignment, which is characteristic of dense connective tissues. MC3T3-E1 osteoblasts were cultured in the collagen scaffolds and were viable after up to 7 days of culture, both in the absence and in the presence of κ-carrageenan. The presence of κ-carrageenan in the collagen scaffolds stimulated the maturation of the cells to a mineralizing phenotype, as suggested by the increased expression of key genes related to bone mineralization, including alkaline phosphatase (Alp), bone sialoprotein (Bsp), osteocalcin (Oc), and osteopontin (Opn), as well as the ability to mineralize the extracellular matrix after 14 and 21 days of culture. Taken together, the results described in this study shed light on the potential use of collagen/κ-carrageenan scaffolds to study the role of the structural organization of bone-mimetic synthetic matrices in cell function.

Biomimetics and the restoration of the endodontically treated tooth / Biomimética e a restauração do dente tratado endodonticamente

Although much progress has been obtained in terms of the Endodontic treatment, the literature shows that true success can be only achieved with adequate coronal seal to avoid bacterial contamination, and protect the tooth structure from fracture. There are many options available to the clinician to restore the endodontically treated tooth; however, there is not much evidence available on what alternative is better than another. This review will critically present the current knowledge on restorative choices, including posts and endocrowns, showing advantages and disadvantages of different treatment forms. With this knowledge, we will also introduce the concept of biomimetics to endodontically treated teeth, and how the nature of their remaining tooth structure can benefit from this approach. This concept entails the use of mechanisms and biologically produced materials to restore a tooth in a way that would mimic its natural structure, with the purpose of achieving better long-term prognosis (AU)

Embora tenha se obtido progresso em relação ao tratamento endodôntico, a literatura mostra que o sucesso real só pode ser atingido com o selamento coronal adequado, para evitar-se a contaminação bacteriana e proteger-se a estrutura dental de fraturas. Há muitas opções disponíveis para o clínico para a restauração do dente tratado endodonticamente; entretanto, não há muita evidência disponível sobre qual alternativa é melhor que a outra. Esta revisão apresentará criticamente o conhecimento atual sobre opções restauradoras, incluindo retentores intraradiculares e endocrowns, mostrando vantagens e desvantagens das diferentes formas de tratamento. Com esse conhecimento, também introduziremos o conceito de biomimética, uma vez que dentes tratados endodonticamente, devido a natureza de sua estrutura dental remanescente, podem se beneficiar desta abordagem. Esse conceito envolve o uso de mecanismos e materiais produzidos biologicamente para restaurar um dente de forma a imitar a estrutura natural, com o objetivo de alcançar melhor prognóstico de longo-prazo.(AU)

Synthesis, characterization and superoxide dismutase activity of a biomimetic Mn(III) complex covalently anchored to mesoporous silica.

A mononuclear Mn(III) complex of a clickable ligand, [Mn(hbpapn)(H2O)2]ClO4·4.5H2O, where H2hbpapn = 1,3-bis[(2-hydroxybenzyl)(propargyl)amino]propane, has been prepared and fully characterized. The complex catalyzes the dismutation of superoxide employing a Mn(III)/Mn(IV) redox cycle, with catalytic rate constant of 3.9 × 106 M-1 s-1 determined through the nitro blue tetrazolium photoreduction inhibition assay, in aqueous medium of pH 7.8. The alkyne function of the ligand was used for the covalent attachment of the catalyst to azide modified mesoporous silicas with different texture and morphology, through click chemistry. In these materials the catalyst is essentially linked to the inner pore walls, isolated and protected from the external medium. The hybrid materials can be recycled, and retain or improve the superoxide dismutase activity of the free catalyst with the pore size of the solid matrix playing a role on the activity of the catalyst.

Cancer Cell Spheroids as a 3D Model for Exploring the Pathobiology of Vasculogenic Mimicry.

Spheroids are 3D spherical cell aggregates, which, cultivated in vitro, behave differently than regular monolayer cellular cultures. Cancer spheroids share many characteristics with in vivo solid tumors, making them a powerful tool in cancer research. The use of cancer spheroids makes it possible to identify the potential of new anticancer pharmacological targets, leading them to be widely used in preclinical oncology research. 3D in vitro models allow the study in detail of many important aspects of the cellular transformation process, such as cell morphology, gene expression, cell-cell and cell-ECM interactions, angiogenesis, and vasculogenic mimicry.In this chapter, the importance of studies using spheroids for current cancer research is described, focusing on vasculogenic mimicry, its morphological structure, and the different methods used in the formation of spheroids. The main method uses agarose to produce the molds for the cancer spheroids, is known as the non-adherent hydrogel micro-mold method, and is being covered in more detail below.

Design and assessment of the biomimetic capabilities of a Voronoi-based cancellous microstructure.

Parameterized cellular microstructures allow for the development of efficient multiscale optimization strategies for the design of Functionally Graded Scaffolds (FGSs). This work assesses the biomimetic capabilities of the Voronoi-based cancelous bone microstructure introduced by Fantini et al. (2016) in terms of histomorphometric and elastic properties. Histomorphometric data of 23 bovine bone specimens and elastic data of 140 human bone specimens are used as reference. Based on the key findings that there exists a strong correspondence between the trabecular thickness and the solid volume fraction for natural cancelous bone, and that the stretching of the Voronoi microstructure is an effective means to induce anisotropy, the generative procedure by Fantini et al. (2016) is assessed and tuned to account for anisotropy and elastic properties. It is shown that the resulting mimetic microstructures have histomorphometric features and elastic properties that are in very good accordance to those of the natural samples. The outcomes of this work are a step forward towards the integration of the Voronoi-based microstructure into multiscale design tools.

The Influence of the Shoe over the Medial Foot Arch and the Lower Limbs Kinematics in Toddlers / A influência de calçados no arco longitudinal medial do pé e na cinemática dos membros inferiores de crianças no início da fase de aquisição de marcha

Abstract Objective To evaluate the biomechanical behavior of the medial longitudinal arch (MLA) of the foot and the kinematic parameters of the lower limbs with biomimetic footwear (BF) and non-biomimetic (NB1, NB2, NB3 and NB4) footwear in children at the beginning of the gait acquisition phase. Methods Four toddlers were evaluated at the beginning of the gait acquisition phase under the following conditions: walking barefoot, ambulation with BF and NB1, NB2, NB3 and NB4 footwear in hard floor. BF is described as biomimetic because of its property of emulating natural and irregular floors through a dynamic internal insole. The MLA and kinematics of the hip, knee, and ankle during gait were evaluated by three-dimensional motion analysis system. The similarity between the kinematic curves of barefoot and footwear conditions was analyzed by root mean square error (RMSE). Results The use of BF presented the highest magnitude of MLA and the greatest difference in relation to barefoot condition (higher RMSE). The BF showed less difference in the kinematics of the knee and ankle joints during gait when compared to barefoot condition (lower RMSE). NB2 footwear presented hip kinematics more similar to barefoot condition (lower RMSE). Conclusion Biomimetics footwear and NB2 shoes (both with wider forefoot region) generated smaller differences in lower limbs compared to barefoot. In addition, the MLA was higher in the BF, probably because different design from other shoes.

Resumo Objetivo Avaliar o comportamento do arco longitudinal medial do pé (ALM) e os parâmetros cinemáticos dos membros inferiores durante a deambulação com calçados biomiméticos (CBs) e não biomiméticos (NB1, NB2, NB3 e NB4) em crianças no início da fase de aquisição da marcha. Métodos Foram avaliadas quatro crianças no início da fase de aquisição da marcha nas seguintes condições: andar descalço, andar com CBs e calçados NB1, NB2, NB3 e NB4 em solo plano. O calçado biomimético é descrito como biomimético por emular pisos naturais e irregulares por meio de uma palmilha interna dinâmica. O ALM e a cinemática do quadril, joelho e tornozelo durante a marcha foram avaliados por meio de sistema de análise do movimento tridimensional. A similaridade entre as curvas cinemáticas das condições descalça e com calçado foi analisada por meio do cálculo de root mean square error (RMSE). Resultados O CB foi o que apresentou maior magnitude do ALM e maior diferença do ALM em relação à condição descalça (maior RMSE). O CB apresentou ainda menor diferença na cinemática das articulações do joelho e tornozelo durante a marcha quando comparado à condição descalça (menor RMSE). O calçado NB2 apresentou a cinemática do quadril mais semelhante à condição descalça (menor RMSE). Conclusão Os calçados CB e NB2 que apresentam a região do antepé mais larga geraram menores diferenças na cinemática dos membros inferiores. Além disso, o ALM foi maior no CB provavelmente devido a seu design ser diferente daquele dos demais calçados.

Biomimetic Catalysts Based on Au@TiO2-MoS2-CeO2 Composites for the Production of Hydrogen by Water Splitting.

The photocatalytic hydrogen evolution reaction (HER) by water splitting has been studied, using catalysts based on crystalline TiO2 nanowires (TiO2NWs), which were synthesized by a hydrothermal procedure. This nanomaterial was subsequently modified by incorporating different loadings (1%, 3% and 5%) of gold nanoparticles (AuNPs) on the surface, previously exfoliated MoS2 nanosheets, and CeO2 nanoparticles (CeO2NPs). These nanomaterials, as well as the different synthesized catalysts, were characterized by electron microscopy (HR-SEM and HR-TEM), XPS, XRD, Raman, Reflectance and BET surface area. HER studies were performed in aqueous solution, under irradiation at different wavelengths (UV-visible), which were selected through the appropriate use of optical filters. The results obtained show that there is a synergistic effect between the different nanomaterials of the catalysts. The specific area of the catalyst, and especially the increased loading of MoS2 and CeO2NPs in the catalyst substantially improved the H2 production, with values of ca. 1114 µm/hg for the catalyst that had the best efficiency. Recyclability studies showed only a decrease in activity of approx. 7% after 15 cycles of use, possibly due to partial leaching of gold nanoparticles during catalyst use cycles. The results obtained in this research are certainly relevant and open many possibilities regarding the potential use and scaling of these heterostructures in the photocatalytic production of H2 from water.

First-in-human endovascular treatment of hydrocephalus with a miniature biomimetic transdural shunt.

Surgical ventriculoperitoneal shunting remains standard treatment for communicating hydrocephalus, despite persistently elevated infection and revision rates. A novel minimally invasive endovascular cerebrospinal fluid (CSF) shunt was developed to mimic the function of the arachnoid granulation which passively filters CSF from the central nervous system back into the intracranial venous sinus network. The endovascular shunt is deployed via a femoral transvenous approach across the dura mater into the cerebellopontine angle cistern. An octogenarian with intractable hydrocephalus following subarachnoid hemorrhage underwent successful endovascular shunting, resulting in swift intracranial pressure reduction from 38 to <20 cmH2O (<90 min) and resolution of ventriculomegaly. This first successful development of a percutaneous transluminal venous access to the central nervous system offers a new pathway for non-invasive treatment of hydrocephalus and the potential for intervention against neurological disorders.

Layer-by-Layer Biomimetic Microgels for 3D Cell Culture and Nonviral Gene Delivery.

Localized release of nucleic acid therapeutics is essential for many biomedical applications, including gene therapy, tissue engineering, and medical implant coatings. We applied the substrate-mediated transfection and layer-by-layer (LbL) technique to achieve an efficient local gene delivery. In the experiments presented herein, we embeded lipoplexes containing plasmid DNA encoding for enhanced green fluorescent protein (pEGFP) within polyelectrolyte alginate-based microgels composed of poly(allylamine hydrochloride) (PAH), chondroitin sulfate (CS), and poly-l-lysine (PLL) with diameters between 70 and 90 µm. Droplet-based microfluidics was used as the main process to produce the alginate (ALG)-based microgels with discrete size, shape, and low coefficient of variation. The physicochemical and morphological properties of the polyelectrolyte microgels were characterized via optical microscopy, scanning electron microscopy (SEM), and zeta potential analysis. We found that polyelectrolyte microgels provide low cytotoxicity and cell-material interactions (adhesion, spreading, and proliferation). In addition, the microsystem showed the ability to load lipoplexes and a loading efficiency equal to 83%, and it enabled in vitro surface-based transfection of MCF-7 cells. This approach provides a new suitable route for cell adhesion and local gene delivery.

Enzyme-mimicking capacities of carbon-dots nanozymes: Properties, catalytic mechanism, and applications - A review.

Nanozymes, novel engineered nanomaterial-based artificial enzymes, have been developed to overcome intrinsic drawbacks exist in natural enzymes including high-cost storage, structural instability, and chemical sensitivity. More recently, carbon dots (CDs) have received significant attention due to their biocompatibility, high catalytic activity, and simple surface functionalization, thus emerging as possible alternatives for biomedical and environmental applications. In this review, we analyze methods and precursors used to synthesize CDs with enzyme-mimicking behaviors. In addition, approaches such as doping or constructing hybrid nanozymes are included as possible strategies to enhance the catalytic performance of CDs. Recent studies have reported CDs that mimic different oxidoreductases, exhibiting peroxidase-, catalase-, oxidase/laccase-, and superoxide dismutase-like activities. Therefore, this review presents a detailed discussion of the mechanism, recent advances, and application for each oxidoreductase-like activity reported on nanozymes based on CDs nanomaterials. Finally, current challenges faced in the successful translation of CDs to potential applications are addressed to suggest research directions.