Composite Central Face Design—An Approach to Achieve Efficient Alginate Microcarriers

Funding: This work was supported by Portuguese Agency for Innovation (PT2020) through the projects (CENTRO-01-0145-FEDER-000014) and (POCI-01-0247-FEDER-017771). It was also supported by the project PAMI – Portuguese Additive Manufacturing Initiative (project nº22158 – SAICT- AAC nº 01/SAICT/2016) and also, by the CDRSP– ID/Multi/04044/2019, funded by the Portuguese Government through FCT/MCTES and co-funded by the European Regional Development Fund through the Partnership Agreement PT2020. This work was also supported by funds from the Health Sciences Research Center (CICS-UBI) through National Funds by FCT - Foundation for Science and Technology (UID / Multi / 00709/2019).Microparticulated drug delivery systems have been used as promising encapsulation systems for protecting drugs for in vitro and in vivo applications, enhancing its stability, providing an increased surface to volume ratio, reducing adverse effects, and hence an improvement in bioavailability. Among the studied microparticles, there is a rising interest in the research of alginate microparticles for pharmaceutical and biomedical fields confirming its potential to be used as an effective matrix for drug and cell delivery. Moreover, calcium alginate has been one of the most extensively forming microparticles in the presence of divalent cations providing prolonged drug release and suitable mucoadhesive properties. Regarding the above mentioned, in this research work, we intended to produce Ca-alginate micro-vehicles through electrospraying, presenting high encapsulation efficiency (EE%), reduced protein release across the time, reduced swelling effect, and high sphericity coefficient. To quickly achieve these characteristics and to perform an optimal combination among the percentage of alginate and CaCl2, design of Experiments was applied. The obtained model presented to be statistically significant (p-value < 0.05), with a coefficient of determination of 0.9207, 0.9197, 0.9499, and 0.9637 for each output (EE%, release, swelling, and sphericity, respectively). Moreover, the optimal point (4% of alginate and 6.6% of CaCl2) was successfully validated.info:eu-repo/semantics/publishedVersio

DoE to improve supercoiled p53-pDNA purification by O-phospho-L-tyrosine chromatography

P53 is implicated in various cellular functions and several studies have shown that transfection of cancer cells with wild-type p53-expressing plasmids could directly drive cells into growth arrest and/or apoptosis. In the present work, the 6.07 kbp pcDNA3-FLAG-p53 plasmid, which encodes the p53 tumor suppressor, was produced and recovered from a recombinant cell culture of Escherichia coli DH5α. Following plasmid biosynthesis, the O phospho-L-tyrosine chromatographic matrix was explored to purify the supercoiled p53-encoding plasmid. In order to quickly determine the optimal chromatographic performance and to obtain the required purity degree, maximizing the recovery yield of the supercoiled plasmid DNA, the Composite Central Face design was applied. The model revealed to be statistically significant (p-value < 0.05), with coefficient of determination of 0.9434 for the recovery yield and 0.9581 for purity and the central point was successfully validated. After the chro matographic process optimization by using the design of experiments tool, 49.7% of the supercoiled p53-en coding plasmid was recovered with 98.2% of purity, when a decreasing ammonium sulphate gradient was ap plied. The dynamic binding capacity of the O-phospho-L-tyrosine agarose column was 0.35 ± 0.02 mg pDNA/ mL matrix at 50% of the breakthrough. Finally, the purified sample was analysed to assess the content of en dotoxins, proteins and genomic DNA, showing that all these impurity levels were below the recommendations of the regulatory agenciesinfo:eu-repo/semantics/publishedVersio

Effect of Chromatographic Conditions on Supercoiled Plasmid DNA Stability and Bioactivity

Funding: This work was supported by FEDER funds through the POCI—COMPETE 2020 Operational Programme Competitiveness and Internationalization in Axis I—Strengthening research, technological development, and innovation (Project POCI-01-0145-FEDER-007491), and National Funds by FCT Foundation for Science and Technology (Project UID/Multi /00709/2013). This work was also developed within the scope of the project CICECO-Aveiro Institute of Materials, FCT Ref. UID/CTM/50011/2019, financed by national funds through the FCT/MCTES. G.M. Azevedo acknowledges the support and fellowship of Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq/203482/2014-0). J.F.A. Valente acknowledges the PhD fellowship (Ref SFRH/BD/96809/2013) from FCT.Acknowledgments: The authors would like to thank Thomas Roberts for providing the pcDNA3–FLAG–p53 construct through Addgene, ref: 10838.The dysfunction of the tumor suppressor gene TP53 has been associated with the pathogenesis of the majority of the cases of cancer reported to date, leading the cell to acquire different features known as the cancer hallmarks. In normal situations, the protein p53 protects the cells against tumorigenesis. By detecting metabolic stress or DNA damage in response to stress, p53 can lead the cell to senescence, autophagy, cell cycle arrest, DNA repair, and apoptosis. Thus, in the case of p53 mutations, it is reasonable to assume that the reestablishment of its function, may restrain the proliferation of cancer cells. The concept of cancer gene therapy can be based on this assumption, and suitable biotechnological approaches must be explored to assure the preparation of gene-based biopharmaceuticals. Although numerous procedures have already been established to purify supercoiled plasmid DNA (sc pDNA), the therapeutic application is highly dependent on the biopharmaceutical’s activity, which can be affected by the chromatographic conditions used. Thus, the present work aims at comparing quality and in vitro activity of the supercoiled (sc) isoform of the p53 encoding plasmid purified by three different amino acids-based chromatographic strategies, involving histidine–agarose, arginine–macroporous, and histidine–monolith supports. The B-DNA topology was maintained in all purified pDNA samples, but their bioactivity, related to the induction of protein p53 expression and apoptosis in cancer cells, was higher with arginine–macroporous support, followed by histidine–monolith and histidine–agarose. Despite the purity degree of 92% and recovery yield of 43% obtained with arginine–macroporous, the sc pDNA sample led to a higher expression level of the therapeutic p53 protein (58%) and, consequently, induced a slightly higher apoptotic effect (27%) compared with sc pDNA samples obtained with histidine–monolithic support (26%) and histidine–agarose support (24%). This behavior can be related to the mild chromatographic conditions used with arginine–macroporous support, which includes the use of low salt concentrations, at neutral pH and lower temperatures, when compared to the high ionic strength of ammonium sulfate and acidic pH used with histidine-based supports. These results can contribute to field of biopharmaceutical preparation, emphasizing the need to control several experimental conditions while adapting and selecting the methodologies that enable the use of milder conditions as this can have a significant impact on pDNA stability and biological activity.info:eu-repo/semantics/publishedVersio

Composite Central Face Design—An Approach to Achieve Efficient Alginate Microcarriers

Microparticulated drug delivery systems have been used as promising encapsulation systems for protecting drugs for in vitro and in vivo applications, enhancing its stability, providing an increased surface to volume ratio, reducing adverse effects, and hence an improvement in bioavailability. Among the studied microparticles, there is a rising interest in the research of alginate microparticles for pharmaceutical and biomedical fields confirming its potential to be used as an effective matrix for drug and cell delivery. Moreover, calcium alginate has been one of the most extensively forming microparticles in the presence of divalent cations providing prolonged drug release and suitable mucoadhesive properties. Regarding the above mentioned, in this research work, we intended to produce Ca-alginate micro-vehicles through electrospraying, presenting high encapsulation efficiency (EE%), reduced protein release across the time, reduced swelling effect, and high sphericity coefficient. To quickly achieve these characteristics and to perform an optimal combination among the percentage of alginate and CaCl2, design of Experiments was applied. The obtained model presented to be statistically significant (p-value &lt; 0.05), with a coefficient of determination of 0.9207, 0.9197, 0.9499, and 0.9637 for each output (EE%, release, swelling, and sphericity, respectively). Moreover, the optimal point (4% of alginate and 6.6% of CaCl2) was successfully validated

Purification of supercoiled p53-encoding plasmid using an arginine-modified macroporous support

This work was supported by FEDER funds through the POCI - COMPETE 2020 - Operational Programme Competitive- ness and Internationalization in Axis I - Strengthening research, technological development and innovation (Project POCI-01-0145- FEDER-007491) and National Funds by FCT - Foundation for Sci- ence and Technology (Project UID/Multi/00709/2019 ). J.F.A. Valente and A. Sousa also acknowledge Ph.D. and Postdoctoral fellowships (Ref SFRH/BD/96809/2013 and Ref SFRH/BPD/102716/2014, respec- tively).p53 is a tumour suppressor gene that has been explored for cancer gene therapy as a possible alter- native to the common treatments. The use of plasmid DNA (pDNA) to carry the therapeutic gene has been considered, but it is requisite to preserve its supercoiled (sc) structure, for eliciting a more effective gene expression and therapeutic action. The purification of the sc pDNA using amino acids-based affinity chromatography has been successfully applied, exploring different amino acids and supports. From these studies, it stood out the selectivity of arginine for the recognition of sc pDNA. However, some limitation on the binding capacity was found in the arginine-agarose support, and in the case of monoliths, some fouling and clogging can limit sequential runs. By using macroporous support modified with arginine it was expected to take advantage of the selectivity of the ligand combined with the flow properties and binding capacity offered by the support. The arginine-modified macroporous support was characterized by SEM, EDX and FTIR also to verify the correct immobilization of arginine, and then used for pDNA pu- rification. The support showed to be effective on the sc p53-pDNA isolation, and the robustness was also achieved by accomplishing the purification of plasmids with different sizes, only by slightly adjusting the experimental conditions. Regarding the dynamic binding capacity of the arginine-modified macrop- orous support, it was achieved an improvement of more than 50% in the pDNA binding capacity when compared with their homologous arginine-agarose commercial matrix, suggesting potential economic fea- sibility in case of scale-up.info:eu-repo/semantics/publishedVersio

O clado Merianthera e as tribos Merianieae e Microliceae (Melastomataceae) na Serra Negra, Minas Gerais

Resumo Apresenta-se um estudo taxonômico do clado Merianthera e das tribos Merianieae e Microlicieae (Melastomataceae) na Serra Negra, localizada no Complexo da Mantiqueira, região sul da Zona da Mata de Minas Gerais, Brasil. O clado Merianthera está representado por Behuria parvifolia, Huberia nettoana e Cambessedesia hilariana, Merianieae está representada apenas por Meriania claussenii, enquanto Microlicieae está representada por Lavoisiera imbricata, Microlicia serpyllifolia, Rhynchanthera dichotoma, Trembleya elegans, Trembleya parviflora e Trembleya phlogiformis. A região vem sofrendo impactos devido à plantação de Pinus e Eucalyptus, especulação imobiliária, visitação desorganizada, coleta ilegal de plantas, bem como o aumento das áreas de pastagem, de modo que várias espécies se encontram sob constante ameaça. Em relação à conservação, deve-se ressaltar as espécies B. parvifolia, H. nettoana e M. claussenii, provavelmente ameaçadas de extinção a nível regional ou nacional. No presente artigo são apresentadas chaves de identificação, descrições, ilustrações, informações sobre distribuição geográfica e comentários morfológicos para os táxons desses grupos representados na Serra Negra