Percepção de aprendizagem on-line na disciplina de biomateriais / Perception of online learning in the biomaterials course

Com as universidades fechadas e a implementação do Ensino Remoto Emergencial, as atividades curriculares ocorreram através de plataformas digitais. O objetivo do presente trabalho foi avaliar a percepção de aprendizagem on-line na disciplina de Biomateriais da Faculdade de Odontologia da Universidade Federal Fluminense no período da pandemia. O questionário COLLES (Constructivist OnLine Learning Environment Survey) foi enviado individualmente por e-mail aos cinquenta alunos, apresentando 24 declarações divididas em seis quesitos: relevância, reflexão crítica, interatividade, apoio dos tutores, apoio entre os colegas e compreensão; e para cada declaração cinco opções de resposta: quase sempre, frequentemente, algumas vezes, raramente e quase nunca. Quarenta e um alunos responderam. A soma das médias obtidas em quase sempre e frequentemente foi de 87,2% para relevância, 70% para reflexão crítica, 33,9% para interatividade, 47,6% para apoio dos tutores, 44,2% para apoio dos colegas e 89,5% para compreensão. Concluiu-se que a relevância, a reflexão crítica e a compreensão apresentaram melhores resultados, enquanto a interatividade, o apoio entre os colegas e o apoio dos tutores demonstraram necessidade de aprimoramento. E apesar das limitações do ERE, a avaliação positiva dos alunos evidenciou esta modalidade de educação on-line como uma solução plausível.

With universities closed and the implementation of Emergency Remote Teaching, curricular activities took place through digital platforms. The objective of this study was to assess the perception of online learning in the Biomaterials course at the Dental School of the Federal Fluminense University during the pandemic. The COLLES questionnaire (Constructivist OnLine Learning Environment Survey) was individually sent via email to fifty students, presenting 24 statements divided into six aspects: relevance, critical reflection, interactivity, tutor support, peer support, and comprehension. For each statement, there were five response options: almost always, often, sometimes, rarely, and almost never. Forty-one students responded. The sum of the averages obtained for almost always and often was 87.2% for relevance, 70% for critical reflection, 33.9% for interactivity, 47.6% for tutor support, 44.2% for peer support, and 89.5% for comprehension. It was concluded that relevance, critical reflection, and comprehension showed better results, while interactivity, peer support, and tutor support demonstrated a need for improvement. Despite the limitations of Emergency Remote Teaching, the positive evaluation from the students highlighted this mode of online education as a plausible solution.

Biocompatible sensors for ammonia gas detection.

In this work, three different dyes have been tested for the determination of gaseous ammonia. This gas is one of the products of microbial degradation and therefore its presence is an indicator of deterioration and could be used as a food freshness indicator. Three different sensors have been prepared and tested, two of them using the natural pigments curcumin and anthocyanin and the other one using bromothymol blue. All of them are biocompatible and therefore allowed to use in contact with food. Different compositions, materials for deposition, stability and reversibility for ammonia gas detection have been studied under high humidity conditions simulating real packaged food conditions. Colorimetry is the technique used to obtain the analytical parameter, the H coordinate of the HSV colour space, simply using a camera, avoiding the use of complex instrumentation. Sensibility, toxicity grade and stability found show that the sensor could be implemented in packaged food and form the basis of a freshness indicator for the food industry.

Cubosomes and hexosomes stabilized by sorbitan monooleate as biocompatible nanoplatforms against skin metastatic human melanoma.

Nanoparticles have become versatile assets in the medical field, providing notable benefits across diverse medical arenas including controlled drug delivery, imaging, and immunological assays. Among these, non-lamellar lipid nanoparticles, notably cubosomes and hexosomes, showcase remarkable biocompatibility and stability, rendering them as optimal choices for theranostic applications. Particularly, incorporating edge activators like sodium taurocholate enhances the potential of these nanoparticles for dermal and transdermal drug delivery, overcoming the stratum corneum, a first line of defense in our skin. This study reports on the formulation of monoolein-based cubosomes and hexosomes incorporating taurocholate and stabilized by Span 80 and co-encapsulating Chlorin e6 and coenzyme QH for photodynamic therapy in skin metastatic melanoma. The formulations were optimized using small-angle X-ray scattering, and cryo-transmission electron microscopy confirmed the presence of cubosomes or hexosomes, depending on the ratio between taurocholate and Span 80. Furthermore, the co-loaded nanoparticles exhibited high encapsulation efficiencies for both Ce6 and the coenzyme QH. In vitro studies on human melanoma cells (Me45) demonstrated the biocompatibility and photodynamic activity of the loaded formulations. These findings show the possibility of formulating more biocompatible cubosomes and hexosomes for photodynamic therapy in skin cancer treatment.

Photothermal switch by gallic acid-calcium grafts synthesized by coordination chemistry for sequential treatment of bone tumor and regeneration.

The residual bone tumor and defects which is caused by surgical therapy of bone tumor is a major and important problem in clinicals. And the sequential treatment for irradiating residual tumor and repairing bone defects has wildly prospects. In this study, we developed a general modification strategy by gallic acid (GA)-assisted coordination chemistry to prepare black calcium-based materials, which combines the sequential photothermal therapy of bone tumor and bone defects. The GA modification endows the materials remarkable photothermal properties. Under the near-infrared (NIR) irradiation with different power densities, the black GA-modified bone matrix (GBM) did not merely display an excellent performance in eliminating bone tumor with high temperature, but showed a facile effect of the mild-heat stimulation to accelerate bone regeneration. GBM can efficiently regulate the microenvironments of bone regeneration in a spatial-temporal manner, including inflammation/immune response, vascularization and osteogenic differentiation. Meanwhile, the integrin/PI3K/Akt signaling pathway of bone marrow mesenchymal stem cells (BMSCs) was revealed to be involved in the effect of osteogenesis induced by the mild-heat stimulation. The outcome of this study not only provides a serial of new multifunctional biomaterials, but also demonstrates a general strategy for designing novel blacked calcium-based biomaterials with great potential for clinical use.

Bone regeneration by a bone substitute biomaterial containing hydroxyapatite, chitosan, xanthan and graphene oxide supplemented with conditioned medium from mesenchymal stem cells.

This study analyzed a recently developed bone substitute biomaterial made of chitosan-xanthanhydroxyapatite-graphene oxide (CXHAG). The CXHAG particles underwent in vitro structural and morphological characterization, and in vivo testing with or without osteogenic conditioned medium from mesenchymal stem cells. Aim: The aim of this study was to determine whether the CXHAG novel biomaterial, supplemented with conditioned medium from mesenchymal stem cells, could be useful for bone regeneration. Materials and Method: For the in vitro study, cells were incubated with 20mg of CXHAG granules for 24 hours and a MTT assay was performed to tests for cytotoxicity. For the in vivo study, critical size calvarial bone defects were created in twenty-five rats. One animal had the defect unfilled (Control Group-CG) and was euthanized after 42 days. Twelve rats received the CXHAG particles (Group 1-G1) and the other twelve received the CXHAG particles supplemented with the conditioned medium (Group 2-G2). All G1/G2 grafts were covered with a CXHAG membrane. G1/G2 animals were euthanized after 14 days (T1) or 42 days (T2). The specimens were processed and histologically evaluated. Results: SEM analysis of the CXHAG particles showed granules of 300-400µm, with a rough irregular surface. They were not cytotoxic to dental pulp stem cells in vitro. The CG specimen showed loose immature connective tissue and no bone formation at the center of the defect. G1 and G2 presented remnant biomaterial particles at both time points, but only G2 had bone formation at the enter of the defect. Conclusions: The conditioned medium had a positive effect on bone regeneration in rat calvarial critical size defects when associated with the novel bone substitute biomaterial.

Este estudo analisou um biomaterial substituto ósseo recentemente desenvolvido feito de óxido de quitosana-xantana-hidroxiapatita-grafeno (CXHAG). As partículas CXHAG observaram caracterização estrutural e morfológica in vitro. Foi testado in vivo, com ou sem meio condicionado osteogênico de células-tronco mesenquimais. Objetivo: O objetivo deste estudo foi determinar se o novo biomaterial CXHAG, suplementado com meio condicionado de células-tronco mesenquimais, poderia ser útil para a regeneração óssea. Materiais e Método: Para o estudo in vitro, as células foram incubadas com 20mg de grânulos de CXHAG por 24 horas e foi realizado ensaio de MTT para verificar a citotoxicidade. Para o estudo in vivo, foram criados defeitos ósseos de tamanho crítico na calvária em vinte e cinco ratos. Um animal teve o defeito não preenchido (Grupo Controle ­ GC) e foi eutanasiado após 42 dias. Doze ratos receberam as partículas CXHAG (Grupo 1 ­ G1) e os outros doze receberam as partículas CXHAG suplementadas com o meio condicionado (Grupo 2 ­ G2). Todos os enxertos G1/G2 foram cobertos com membrana CXHAG. Os animais do G1/G2 foram eutanasiados após 14 dias (T1) ou 42 dias (T2). Os espécimes foram processados e avaliados histologicamente. Resultados: A análise SEM das partículas CXHAG mostrou grânulos de 300-400µm, com superfície áspera e irregular. Eles não foram citotóxicos para células-tronco da polpa dentária in vitro. As amostras CG mostraram tecido conjuntivo imaturo frouxo e nenhuma formação óssea no centro do defeito. G1 e G2 apresentaram partículas remanescentes de biomateriais em ambos os momentos, mas apenas G2 apresentou formação óssea no centro do defeito. Conclusões: O meio condicionado teve repercussões positivas na regeneração óssea em defeitos críticos de calvária de ratos quando associado ao novo biomaterial substituto ósseo.

Aminoacid functionalised magnetite nanoparticles Fe3O4@AA (AA = Ser, Cys, Pro, Trp) as biocompatible magnetite nanoparticles with potential therapeutic applications.

Magnetic nanoparticles (MNPs) are of great interest for their wide applications in biomedical applications, such as bioimaging, antitumoral therapies, regenerative medicine, and drug delivery. The work aimed to obtain biocompatible magnetite nanoparticles coated with amino acids of the general formula Fe3O4@AA (AA = L-tryptophan, L-serine, L-proline and L-cysteine) for potential therapeutic application in anticancer drug delivery. The obtained materials were characterised using XRD, FTIR, DLS analysis, SEM, thermogravimetry (TG), differential scanning calorimetry (DSC), and UV-vis spectroscopy. The photocatalytic, cytotoxic and antimicrobial activity tests of the obtained materials were carried out. The choice of amino acid determines the properties of the material and its future use, for example, Fe3O4@Cys supports radical production, which may increase the efficiency of catalytic degradation, while tryptophan captures radicals, which may be an advantage in several biomedical applications. Fe3O4@Trp exhibited good antimicrobial activity (MBEC and MIC) against E. coli ATCC 25922, P. aeruginosa ATCC 27853 and C. albicans ATCC 10231 while Fe3O4@Pro exhibited the best results against S. aureus ATCC 25923.

Advances in stimuli-responsive injectable hydrogels for biomedical applications.

Injectable hydrogels, as a class of highly hydrated soft materials, are of interest for biomedicine due to their precise implantation and minimally invasive local drug delivery at the implantation site. The combination of in situ gelation ability and versatile therapeutic agent/cell loading capabilities makes injectable hydrogels ideal materials for drug delivery, tissue engineering, wound dressing and tumor treatment. In particular, the stimuli-responsive injectable hydrogels that can respond to different stimuli in and out of the body (e.g., temperature, pH, redox conditions, light, magnetic fields, etc.) have significant advantages in biomedicine. Here, we summarize the design strategies, advantages, and recent developments of stimuli-responsive injectable hydrogels in different biomedical fields. Challenges and future perspectives of stimuli-responsive injectable hydrogels are also discussed and the future steps necessary to fulfill the potential of these promising materials are highlighted.

The impact of the physicochemical properties of calcium phosphate ceramics on biocompatibility and osteogenic differentiation of mesenchymal stem cells.

OBJECTIVE: In this study we have focused on biocompatibility and osteoinductive capacity analysis of self-manufactured single-phase (HAP) and two-phase (HAP and ß-ТСР) bioactive ceramics with various chemical modifications (Fig. 1). RESULTS: We demonstrate a reduction in solubility for all analyzed composite after the treatment with H2O and H2O2, accompanied by an enhancement in adsorption activity. This modification also resulted in an increase in micro- and macroporosity, along with a rise in the open porosity. Adipose-derived mesenchymal stromal cells demonstrated excellent cell adhesion and survival when cultured with these ceramics. Calcium phosphate ceramics (H-500, HT-500, and HT-1 series) stimulated alkaline phosphatase expression, promoted calcium deposition, and enhanced osteopontin expression in ADSCs, independently inducing osteogenesis without additional osteogenic stimuli. These findings underscore the promising potential of HAP-based bioceramics for bone regeneration/reconstruction.

[Clinical analysis of biomaterial-silicone keel complex in the vocal folds adhesion treatment].

Objective:To retrospectively analyze the clinical effect of biomaterial combined with silicone keel technology in the prevention and treatment of vocal folds adhesion. Methods:The basic data, perioperative conditions and prognosis of 21 cases of vocal folds adhesion treated by biofilm-silicone keel complex were retrospectively analyzed in Huashan Hospital Fudan University. Results:A total of 21 patients were enrolled in this study（19 males（90.5%）, 2 females（9.5%）. Among these patients, 18 cases of early glottic laryngeal carcinoma（T1b）, 1 case of bilateral vocal folds leukoplecta and 2 cases of postoperative vocal folds adhesion. No accidental rupture of the silicone keel occurred during perioperative period, and the silicone keel was removed in 22.4±2.6 days. All patients were reviewed after removing the silicone keel, the overall effective rate was 90.5%（19/21）. Postoperative complications occurred in 5 patients（1 laryngeal infection, 4 granulation tissue hyperplasia）, all of whom were cured after conservative treatment. Conclusion:This study explored the feasibility of biomaterial in the treatment of vocal folds adhesion. The biomaterial-silicone keel complex technology is simple to operate and has effect on the prevention of vocal folds adhesions, which is worth of clinical promotion.

Role of Piezoelectricity in Disease Diagnosis and Treatment: A Review.

Because of their unique electromechanical coupling response, piezoelectric smart biomaterials demonstrated distinctive capability toward effective, efficient, and quick diagnosis and treatment of a wide range of diseases. Such materials have potentiality to be utilized as wireless therapeutic methods with ultrasonic stimulation, which can be used as self-powered biomedical devices. An emerging advancement in the realm of personalized healthcare involves the utilization of piezoelectric biosensors for a range of therapeutic diagnosis such as diverse physiological signals in the human body, viruses, pathogens, and diseases like neurodegenerative ones, cancer, etc. The combination of piezoelectric nanoparticles with ultrasound has been established as a promising approach in sonodynamic therapy and piezocatalytic therapeutics and provides appealing alternatives for noninvasive treatments for cancer, chronic wounds, neurological diseases, etc. Innovations in implantable medical devices (IMDs), such as implantable piezoelectric energy generator (iPEG), offer significant advantages in improving physiological functioning and ability to power a cardiac pacemaker and restore the heart function. This comprehensive review critically evaluates the role of piezoelectricity in disease diagnosis and treatment, highlighting the implication of piezoelectric smart biomaterials for biomedical devices. It also discusses the potential of piezoelectric materials in healthcare monitoring, tissue engineering, and other medical applications while emphasizing future trends and challenges in the field.

Closure of oroantral communications using heterologous biomaterials stabilized by porcine cortical lamina: A case series.

PURPOSE: To describe a surgical technique for oroantral communication closure and bone regeneration that can meet the needs of an effective, less invasive, and simpler surgery using approaches and biomaterials used in guided bone regeneration (GBR) techniques. The main objective was to close the communication, and the secondary was to achieve bone regeneration. METHODS: This retrospective and monocentric case series was conducted using data obtained from the medical records of 28 patients with oroantral communications with bone deficits greater than 3 mm and treated with heterologous cortico-cancellous graft covered with resorbable collagen membranes and heterologous cortical lamina. The primary outcome was closure of the communication, and the secondary outcome was bone augmentation, both tested radiographically and clinically. RESULTS: 28 subjects were treated consecutively for the closure of oroantral communications. The subjects included 16 men and 12 women. The mean age was 57.5 years. Closure was successful in all 28 cases, and radiographic control after 6 months showed bone regeneration in all the cases. This technique was effective in isolating the maxillary sinus from the oral cavity, showing results in terms of seal and healing, and bone regeneration. CLINICAL SIGNIFICANCE: Oroantral communications are frequent in dentistry, requiring special expertise and interventions affecting patient morbidity. The use of a heterologous cortical lamina can allow effective closure of the communication, preventing migration of pathological epithelia while increasing the bone ridge.

Natural polymeric biomaterials for managing peripheral nerve injuries : a novel approach for tissue repair and reconstruction.

Peripheral nerve injury serves as a major challenge to clinicians and researchers due to the complexity and functions of peripheral nerves that play the crucial role of transmitting signals between spinal cord and other human body tissues. Biomaterials offer promising solutions for regeneration of nerve tissues owing to their biodegradability, and biocompatibility. They can be fabricated as hydrogels, scaffolds, nanofibrous matrices, and nanoparticles that can facilitate the release of therapeutic molecules to reduce inflammation and promote neuronal growth. Managing peripheral nerve injuries through natural polymeric based biomaterials represents as a novel approach for tissue repair and reconstruction in the field of regenerative medicine. This correspondence will give an insight into the different types of natural polymeric biomaterials that can be efficiently used in managing peripheral nerve injuries.

Biocompatible Poly(ε-Caprolactone) Nanocapsules Enhance the Bioavailability, Antibacterial, and Immunomodulatory Activities of Curcumin.

Curcumin (Cur), the primary curcuminoid found in Curcuma longa L., has garnered significant attention for its potential anti-inflammatory and antibacterial properties. However, its hydrophobic nature significantly limits its bioavailability. Additionally, adipose-derived stem cells (ADSCs) possess immunomodulatory properties, making them useful for treating inflammatory and autoimmune conditions. This study aims to verify the efficacy of poly(ε-caprolactone) nanocapsules (NCs) in improving Cur's bioavailability, antibacterial, and immunomodulatory activities. The Cur-loaded nanocapsules (Cur-NCs) were characterized for their physicochemical properties (particle size, polydispersity index, Zeta potential, and encapsulation efficiency) and stability over time. A digestion test simulated the behavior of Cur-NCs in the gastrointestinal tract. Micellar phase analyses evaluated the Cur-NCs' bioaccessibility. The antibacterial activity of free Cur, NCs, and Cur-NCs against various Gram-positive and Gram-negative strains was determined using the microdilution method. ADSC viability, treated with Cur-NCs and Cur-NCs in the presence or absence of lipopolysaccharide, was analyzed using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide assay. Additionally, ADSC survival was assessed through the Muse apoptotic assay. The expression of both pro-inflammatory (interleukin-1ß and tumor necrosis factor-α) and anti-inflammatory (IL-10 and transforming growth factor-ß) cytokines on ADSCs was evaluated by real-time polymerase chain reaction. The results demonstrated high stability post-gastric digestion of Cur-NCs and elevated bioaccessibility of Cur post-intestinal digestion. Moreover, Cur-NCs exhibited antibacterial activity against Escherichia coli without affecting Lactobacillus growth. No significant changes in the viability and survival of ADSCs were observed under the experimental conditions. Finally, Cur-NCs modulated the expression of both pro- and anti-inflammatory cytokines in ADSCs exposed to inflammatory stimuli. Collectively, these findings highlight the potential of Cur-NCs to enhance Cur's bioavailability and therapeutic efficacy, particularly in cell-based treatments for inflammatory diseases and intestinal dysbiosis.

Osteogenic Potential and Long-Term Enzymatic Biodegradation of PHB-based Scaffolds with Composite Magnetic Nanofillers in a Magnetic Field.

Millions of people worldwide suffer from musculoskeletal damage, thus using the largest proportion of rehabilitation services. The limited self-regenerative capacity of bone and cartilage tissues necessitates the development of functional biomaterials. Magnetoactive materials are a promising solution due to clinical safety and deep tissue penetration of magnetic fields (MFs) without attenuation and tissue heating. Herein, electrospun microfibrous scaffolds were developed based on piezoelectric poly(3-hydroxybutyrate) (PHB) and composite magnetic nanofillers [magnetite with graphene oxide (GO) or reduced GO]. The scaffolds' morphology, structure, mechanical properties, surface potential, and piezoelectric response were systematically investigated. Furthermore, a complex mechanism of enzymatic biodegradation of these scaffolds is proposed that involves (i) a release of polymer crystallites, (ii) crystallization of the amorphous phase, and (iii) dissolution of the amorphous phase. Incorporation of Fe3O4, Fe3O4-GO, or Fe3O4-rGO accelerated the biodegradation of PHB scaffolds owing to pores on the surface of composite fibers and the enlarged content of polymer amorphous phase in the composite scaffolds. Six-month biodegradation caused a reduction in surface potential (1.5-fold) and in a vertical piezoresponse (3.5-fold) of the Fe3O4-GO scaffold because of a decrease in the PHB ß-phase content. In vitro assays in the absence of an MF showed a significantly more pronounced mesenchymal stem cell proliferation on composite magnetic scaffolds compared to the neat scaffold, whereas in an MF (68 mT, 0.67 Hz), cell proliferation was not statistically significantly different when all the studied scaffolds were compared. The PHB/Fe3O4-GO scaffold was implanted into femur bone defects in rats, resulting in successful bone repair after nonperiodic magnetic stimulation (200 mT, 0.04 Hz) owing to a synergetic influence of increased surface roughness, the presence of hydrophilic groups near the surface, and magnetoelectric and magnetomechanical effects of the material.

Modification of transvaginal polypropylene mesh with co-axis electrospun nanofibrous membrane to alleviate complications following surgical implantation.

BACKGROUND: Surgeries for treating pelvic organ prolapse involving the utilization of synthetic mesh have been associated with complications such as mesh erosion, postoperative pain, and dyspareunia. This work aimed to reduce the surgical implantation-associated complications by nanofibrous membranes on the surface of the polypropylene mesh. The nanofiber of the nanofibrous membrane, which was fabricated by co-axial electrospinning, was composed of polyurethane as fiber core and gelatin as the fiber out layer. The biocompatibility of the modified mesh was evaluated in vitro by cell proliferation assay, immunofluorescence stain, hematoxylin-eosin (HE) staining, and mRNA sequencing. Polypropylene mesh and modified mesh were implanted in a rat pelvic organ prolapse model. Mesh-associated complications were documented. HE and Picro-Sirius red staining, immunohistochemistry, and western blotting were conducted to assess the interactions between the modified mesh and vaginal tissues. RESULTS: The modified mesh significantly enhanced the proliferation of fibroblasts and exerted a positive regulatory effect on the extracellular matrix anabolism in vitro. When evaluated in vivo, no instances of mesh exposure were observed in the modified mesh group. The modified mesh maintained a relatively stable histological position without penetrating the muscle layer or breaching the epidermis. The collagen content in the vaginal wall of rats with modified mesh was significantly higher, and the collagen I/III ratio was lower, indicating better tissue elasticity. The expression of metalloproteinase was decreased while the expression levels of tissue inhibitor of metalloproteinase were increased in the modified mesh group, suggesting an inhibition of collagen catabolism. The expression of TGF-ß1 and the phosphorylation levels of Smad3, p38 and ERK1/2 were significantly increased in the modified mesh group. NM significantly improved the biocompatibility of PP mesh, as evidenced by a reduction in macrophage count, decreased expression levels of TNF-α, and an increase in microvascular density. CONCLUSIONS: The nanofibrous membrane-coated PP mesh effectively reduced the surgical implantation complications by inhibiting the catabolism of collagen in tissues and improving the biocampibility of PP mesh. The incorporation of co-axial fibers composed of polyurethane and gelatin with polypropylene mesh holds promise for the development of enhanced surgical materials for pelvic organ prolapse in clinical applications.

Robust Natural Light-Absorbable and -Degradable AIE Photosensitizers for Fluorescence Labeling and Efficient Photodynamic Eradication of Algal Pollutants.

Current water pollution caused by the excessive proliferation of harmful algae urges green methods that can efficiently utilize natural light to treat algal pollution. Herein, a series of aggregation-induced emission (AIE) photosensitizers that can efficiently harness sunshine were synthesized for the environmentally friendly and biocompatible treatment of algal pollution. By tuning the number of thiophene units and the electron conjugation degree, the photosensitizers' absorptions were broadened to cover the whole visible light range. The positive charges guided photosensitizers to aggregate on algal cell surfaces, resulting in a turn-on fluorescence signal and robust reactive oxygen species generation under sunshine, thereby achieving fluorescence labeling and photodynamic eradication of algae. The eradication outcomes demonstrated that the AIE photosensitizers significantly outperformed the commercial algaecide ALG. At 20 ppm photosensitizers, 90.4% and 94.2% killing rates were achieved for C. reinhardtii and C. vulgaris, respectively, 2.8- and 3.6-fold higher than those from the same concentration of ALG. Excellent performances in inhibiting algae growth were also verified with efficiency superior to that of ALG. Importantly, the photosensitizers can self-degrade into biocompatible fragments under irradiation to avoid secondary pollution. The developed photosensitizers that possess sunshine convertibility and degradability provide an efficient tool for algal treatment, showing broad research and application prospects.

Determination of the Optimum Architecture of Additively Manufactured Magnetic Bioactive Glass Scaffolds for Bone Tissue Engineering and Drug-Delivery Applications.

For better bone regeneration, precise control over the architecture of the scaffolds is necessary. Because the shape of the pore may affect the bone regeneration, therefore, additive manufacturing has been used in this study to fabricate magnetic bioactive glass (MBG) scaffolds with three different architectures, namely, grid, gyroid, and Schwarz D surface with 15 × 15 × 15 mm3 dimensions and 70% porosity. These scaffolds have been fabricated using an in-house-developed material-extrusion-based additive manufacturing system. The composition of bioactive glass was selected as 45% SiO2, 20% Na2O, 23% CaO, 6% P2O5, 2.5% B2O3, 1% ZnO, 2% MgO, and 0.5% CaF2 (wt %), and additionally 0.4 wt % of iron carbide nanoparticles were incorporated. Afterward, MBG powder was mixed with a 25% (w/v) Pluronic F-127 solution to prepare a slurry for fabricating scaffolds at 23% relative humidity. The morphological characterization using microcomputed tomography revealed the appropriate pore size distribution and interconnectivity of the scaffolds. The compressive strengths of the fabricated grid, gyroid, and Schwarz D scaffolds were found to be 14.01 ± 1.01, 10.78 ± 1.5, and 12.57 ± 1.2 MPa, respectively. The in vitro study was done by immersing the MBG scaffolds in simulated body fluid for 1, 3, 7, and 14 days. Darcy's law, which describes the flow through porous media, was used to evaluate the permeability of the scaffolds. Furthermore, an anticancer drug (Mitomycin C) was loaded onto these scaffolds, wherein these scaffolds depicted good release behavior. Overall, gyroid-structured scaffolds were found to be the most suitable among the three scaffolds considered in this study for bone tissue engineering and drug-delivery applications.

Development of an Intracellular Nitric Oxide-Donating Cell-Penetrating Polypeptide as an Immunogenic Cell Death Inducer.

Recently, nitric oxide (NO) has been shown to induce immunogenic cell death (ICD) in tumor cells through endoplasmic reticulum (ER) stress and mitochondrial outer membrane permeabilization (MOMP). However, NO is unstable, making direct delivery difficult. In this study, we developed a cell-penetrating polypeptide-based NO donor, poly(l-guanidine) (PLG). Given that the guanidine structure can be catalyzed by reactive oxygen species (ROS) to produce NO, helical PLG plays three roles: spontaneous cell penetration, intracellular ROS generation to produce NO, and induction of ICD. The results revealed that helical PLG generates NO inside the cell by self-inducible guanidine oxidation and that NO effectively elicits ICD by ER stress- and MOMP-dependent intertwined mechanisms.

Chitosan-glucose derivative membrane obtained by Maillard reaction improves cartilage repair in a rabbit model.

BACKGROUND: Treatment of articular cartilage injury remains a challenging clinical problem in orthopedics. Chitosan-derived biomaterial could be a potential adjuvant treatment to improve cartilage repair. In the current study, we examined the effects of two potential chitosan-derived materials on cartilage regeneration of osteochondral defects in rabbits. METHODS: An osteochondral defect was created over the rabbit knee and treated using three approaches: group A received no material (n = 24), group B received chitosan membranes with glucose absorption (CGA; n = 25), and group C received chitosan-glucose derivative membranes obtained via the Maillard reaction (CGMR; n = 25). Cartilage repair over the osteochondral defect was analyzed 12 weeks post-surgery via histological analysis, immunostaining, and reverse transcription-qualitative polymerase chain reaction (RT-qPCR) for type-I and type-II collagen mRNA. RESULTS: According to histological analysis, CGMR-treated defects showed significantly improved modified O'Driscoll scoring when compared with no material- and CGA-treated defects (20.9 ± 4.3 vs. 13.00 ± 2.5 and 17.7 ± 4.6, p < 0.001). Moreover, group C exhibited higher intensity of type-II collagen immunohistochemical staining over the regenerated cartilage than groups A and B, along with increased expression of type-II collagen mRNA by RT-qPCR. CONCLUSIONS: CGMR might improve cartilage regeneration in osteochondral defects.

Banana fruit (Musa sp.) DNA-magnetite nanoparticles: Synthesis, characterization, and biocompatibility assays on normal and cancerous cells.

Magnet-mediated gene therapy has gained considerable interest from researchers as a novel alternative for treating genetic disorders, particularly through the use of superparamagnetic iron oxide nanoparticles (NPs)-such as magnetite NPs (Fe3O4NPs)-as non-viral genetic vectors. Despite their commercial availability for specific genetic transfection, such as in microglia cell lines, many potential uses remain unexplored. Still, ethical concerns surrounding the use of human DNA often impede genetic research. Hence, this study examined DNA-coated Fe3O4NPs (DNA-Fe3O4NPs) as potential transfection vectors for human foreskin fibroblasts (HFFs) and A549 (lung cancer) cell lines, using banana (Musa sp.) as a low-cost, and bioethically unproblematic DNA source. Following coprecipitation synthesis, DNA-Fe3O4NP characterization revealed a ζ-potential of 40.65 ± 4.10 mV, indicating good colloidal stability in aqueous media, as well as a superparamagnetic regime, evidenced by the absence of hysteresis in their magnetization curves. Successful DNA coating on the NPs was confirmed through infrared spectra and surface analysis results, while magnetite content was verified via characteristic X-ray diffraction peaks. Transmission electron microscopy (TEM) determined the average size of the DNA-Fe3O4NPs to be 14.69 ± 5.22 nm. TEM micrographs also showed no morphological changes in the DNA-Fe3O4NPs over a 30-day period. Confocal microscopy of HFF and A549 lung cancer cell lines incubated with fluoresceinamine-labeled DNA-Fe3O4NPs demonstrated their internalization into both the cytoplasm and nucleus. Neither uncoated Fe3O4NPs nor DNA-Fe3O4NPs showed cytotoxicity to A549 lung cancer cells at 1-50 µg/mL and 25-100 µg/mL, respectively, after 24 h. HFFs also maintained viability at 1-10 µg/mL for both NP types. In conclusion, DNA-Fe3O4NPs were successfully internalized into cells and exhibited no cytotoxicity in both healthy and cancerous cells across a range of concentrations. These NPs, capable of binding to various types of DNA and RNA, hold promise for applications in gene therapy.