JUSTINE PAULA RAMOS DE OLIVEIRA

JUSTINE PAULA RAMOS DE OLIVEIRA

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Solubility study of Kraft lignin for the development of electrospun nanofibers
2022 - NOGUEIRA, K.M.; VARCA, J.O.; LIMA, C.S.; CRUZ, C.C. da; RIBEIRO, A.H.; FREITAS, L.F.; VARCA, G.H.; LUGAO, A.B.
Lignin is a high-volume byproduct of paper manufacturing which has been explored in many research fields, especially for the development of fiber and nanofiber for biomedical applications [1,2]. This work presents a solubility study performed through gravimetry for kraft lignin considering its application for the development of electrospun nanofibers [3]. In practical terms, lignin was solubilized in alkaline aqueous solution, dimethylformamide and dimethylsulfoxide, at concentrations of 10, 15 and 20% (w/v) and varying temperatures of 25, 50 and 75 ºC, under constant stirring. After solubilizing, the solution was filtered, and the insoluble fraction was dried in the oven at 100 ºC. At 25 ºC lignin was insoluble in all solvents tested, as predicted using Hansen solubility parameters. Although the increase in temperature promoted lignin solubilization in all solvents tested, at the highest temperature assayed, the solubilization was facilitated, presenting the smallest levels of the insoluble fraction. Lignin was soluble in all solvents tested, and optimum solubility conditions were achieved using 10% lignin solutions (w/v), without significant insoluble fraction, and therefore ideal concentration for the development of lignin based fibers.
A biological study of gelatin-PVA based scaffold functionalized with albumin for biomedical purposes
2022 - VARCA, J.O.; KLINGBEIL, F.; NOGUEIRA, K.M.; LIMA, C.S.; CRUZ, C.C. da; FREITAS, L.F.; VARCA, G.H.; MATHOR, M.B.; LUGAO, A.B.
Biomaterials have been designed for tissue reconstruction, bone regeneration and cell culture, and functionalized with presence of proteins, nanoparticles, peptides and other components to improve the biocompatibility for instance. This work shows a biological study of gelatin-PVA based scaffold with controlled pore size and functionalized with albumin for biomedical purposes. The in vitro study comprises cytotoxicity, cell adhesion and proliferation assessment. In practical terms, the gelatin-PVA scaffold crosslinked and sterilized by gamma radiation followed by freeze-drying was evaluated by cytotoxicity, adhesion and proliferation tests. The cytotoxicity results showed that the biomaterial produced was non-toxic, and adhesion and proliferation assays showed that the material was suitable for tissue engineering. The presence of albumin did not present a significant impact on the cell performance, at the assayed concentration.
Development of Lignin/PEO nanofibers by electrospinning technique for tissue engineering application
2020 - NOGUEIRA, K.M.; VARCA, J.O.; LIMA, C.S.; CRUZ, C.C. da; RIBEIRO, A.H.; FREITAS, L.F.; VARCA, G.H.; LUGAO, A.B.
Lignin is a renewable carbon source and has been widely explored in different areas over the last years, especially in biomaterials such as dressings and other biomedical devices due its natural origin and low cost. Its chemical structure confers interesting properties such as antioxidant capacity, UV protection, bactericidal action and appropriate adsorption. Poly (ethylene oxide) (PEO) is used in electrospinning to facilitate the formation polymer fibers. The electrospinning technique has been largely explored in the bioengineering area towards designing nanomaterial with minimum defect and high surface area. The present work aimed the development of a lignin/PEO nanofiber by electrospinning technique. In practical terms, lignin/PEO solution was prepared following two different methods. In the first approach, polymer stock solutions were prepared in alkaline water by stirring at 70 °C. In the second, the polymer powders were mixed and dissolved together in dimethylformamide (DMF) under stirring at 80 °C. By both methods, PEO/lignin solutions were prepared at 10, 20 e 30% (w,v) solid content, at the ratios 99/1 and 95/5. For electrospinning parameters, the distance between ejector and plate collector was set to 15-20 cm, voltage to 20 kV and injection flow to 1 mL/h, chamber temperature to 40 °C and 30%. Nanofiber morphology was assessed by scanning electron microscopy and optical coherence tomography. Apparent porosity was measured by classical Archimedes method. Due to higher DMF dielectric constant compared to water, results showed that nanofibers made using DMF presented smaller beats formation and smaller fiber diameter. Nanofibers with higher solid content presented more uniform fibers with larger diameter. Nanofibers with higher lignin concentration presented larger number of beats and higher fiber diameter. However, lignin improved the system porosity in all cases. Further mechanical and biological experiments will be done, nevertheless, the nanofiber developed is a promising material to be applied in tissue engineering.
CMC and PVA hydrogel containing papain nanoparticles for drug delivery
2020 - LIMA, C.S.; VARCA, G.H.; OLIVEIRA, J.R.; NOGUEIRA, K.M.; SANTOS, F.A.; RIBEIRO, A.H.; LUGAO, A.B.; FREITAS, L.F.; ROGERO, S.O.
Four hydrogel formulations of Carboxymethylcellulose (CMC) and Poly (vinyl alcohol) (PVA) were prepared with native papain (AP and BP) and papain nanoparticles (AN and BN) for drug delivery. The formulations were evaluated for their preliminary stability, protein distribution in the matrix and cytotoxicity. Three methods for sterilization purposes were compared: irradiation by 60Co source, electron-beam and UV light. The preliminary stability test confirmed that the system was stable since there was no precipitation or alteration of the organoleptic properties of the samples in the evaluated period. The distribution of proteins in the hydrogel was very homogeneous in all the formulations. Quantification of the enzymatic activity of papain after contact with the gel showed that native papain maintained its activity high (86% and 93% for AP and BP gels, respectively), whereas there was a considerable drop in the activity of the papain nanoparticles to 60.54% and 69.44% for AP and BP gels, respectively. Such loss of activity is attributed to processing and/or process steps. The cell viability assay showed that the polymer matrix shows no cytotoxicity, corroborating with the literature, since the material is biocompatible. Thus, it is possible to affirm that the developed system presents potential for biomedical application, either as a vehicle of papain itself or for the transport of other drugs through complexation with papain nanoparticles. However, the need for further studies of stability, controlled release capacity and biocompatibility is required.
The effects gamma radiation dose on the swelling capacity of PVP/lignin hydrogels dressings for wound treatment
2019 - NOGUEIRA, K.M.; VARCA, J.O.; LIMA, C.S.A.; VARCA, G.; LUGAO, A.B.; FREITAS, L.F.
Lignin is a carbon renewable source and has been widely explored in different areas in the last years, especially in the biomaterials field as dressings and other biomedical devices due its natural origin and low cost (1). Its chemical structure confers important properties to this macromolecule such as antioxidant capacity, UV protection and bactericidal activity (2,3). Polivinylpirrolidone (PVP) is a polymer widely applied for biomedical applications due to its relevant properties, such as the water absorption capacity, suitable mechanical properties for wound healing applications, and the capacity to originate hydrogels with different characteristics (4). Gamma radiation is a relevant option to produce biomedical devices, as the technology allows polymer crosslinking and sterilization in a single step (5). Two polymer solutions were prepared, PVP 10% (w, v) in distiled water (neutral pH) with poly(ethylene glycol) diacrylate (1.0% w/v) and lignin 6% (w, v) (pH > 13) and homogenized separately, until complete dissolution. The solutions were mixed in the follow ratios 95/5, 90/10 and 80/20, in which were added to a 2% (w, v) of agar and mixed at 70 ºC for 30 minutes. Samples were disposed in glass moulds and irradiated at 25, 50 and 100 kGy at dose rate of 5 kGy/h in a 60Co irradiator. Samples assessed by autoclave presented higher swelling than the PVP control, but lower gel fraction in comparison with the standard, except for formulation 90:10. Swelling and Gel Fraction were also evaluated by shaker at 37 ºC for 24 h. The results showed that the increase of dose decrease the swelling capacity and gel fraction decrease with the increase of lignin in the formulations. In general, the hydrogels irradiated at 25 and 50 kGy, except for formulation 80:20 at 25 kGy, presented good integrity and suitable results to be considered for the next steps of the study and are promising for biomedical application.
Natural polymer hydrogels with gold nanoparticles for bladder cancer chemotherapy delivery
2019 - LIMA, C.S.A.; VARCA, G.; DE FREITAS, L.F.; VARCA, J.O.; LUGAO, A.B.
The treatment of bladder cancer is done by transurethral resection for tumor removal, followed by immune or chemotherapy intravesical, according to the stage of the disease. The main objective of this work was to develop and characterize strategies to increase the residence time and specificity of chemotherapy through the application of hydrogels for chemotherapy and /or immunotherapy administration. Natural polymers gellan gum and microcrystalline cellulose were chosen to prepare the hydrogels as they are already widely used in the biomedical area due to characteristics such as the absence of toxicity, high biocompatibility, and biodegradability. Papain-coated gold nanoparticles were added to the gels to promote chemo or immunotherapeutic permeation. Preliminary stability assays were carried out to evaluate the compatibility between the polymeric matrices and the gold nanoparticles. The systems were characterized by Scanning Electron Microscopy, and Fourier Transform Infrared Spectroscopy. The results allowed the identification of the polymer groups present in the formulations, as well as the evaluation of the interactions between the hydrogel network and the nanoparticles. The formulations were suitable for the proposed application.
Influence of different gamma radiation doses on PVA/gelatin based scaffolds
2017 - OLIVEIRA, JUSTINE P.R. de; OLIVEIRA, MARIA J.A. de; SILVA, ISABELA C. da; VARCA, GUSTAVO H.C.; LUGAO, ADEMAR B.
The present work aimed to study the influence of different radiation doses on a polymer blend at cryogenic and room temperature by means of crosslinking formation, pore size, morphology, topography and mechanical properties. The scaffold was prepared based on two formulations, one composed by gelatin (7%, w/w) and PVA (5%, w/w), and the second by gelatin (10%, w/w) and PVA (5%, w/w). The formulations were separately solubilized in distilled water and heated up to 80 ºC under constant stirring for 1 hour. Posteriorly, both blends were disposed in circular glass moulds. Half of samples was frozen for at least 24 h and then irradiated at 15, 25 and 50 kGy. The other half was cooled at 4 ºC for at least 24 h and then irradiated using the same doses. After irradiation both sample groups were frozen and freeze dried. The scaffold was characterized in terms of structure and morphology by mechanical assays, differential scanning calorimetry, scanning electron microscopy, optical coherence tomography and infrared spectroscopy. In addition, platelet adhesion and release, and cytotoxic assays were also performed. Samples irradiated at 15 kGy presented pore size diameter of around 1.4 μm and porosity of 54%, while samples irradiated at 25 kGy, presented pore size diameter of around 1.1 μm and porosity of 49%. Optical coherence tomography showed that gelatin control samples presented more superficial degradation as irradiation dose increased, while PVA control sample presented higher integrity, indicating that this polymer is less sensitive to gamma radiation. The system presented suitable mechanical properties and the platelet adhesion and release assays showed that the scaffold presented adequate pore size range to host and release the platelets, and non-cytotoxic to platelets, featuring adequate properties to be applied as dressing for wound treatments.
The effect of radiation dose rate over the formation of protein-based nanoparticles for nanosized delivery of chemo and radiotherapeutics
2018 - VARCA, G.H.C.; FAZOLIN, G.N.; FERREIRA, A.H.; OLIVEIRA, J.P.R. de; MARQUES, F.; LUGAO, A.B.
Recent studies demonstrated the development of papain and bovine serum albumin nanoparticles using gamma radiation (10 kGy) in presence of 20-30% (v/v) ethanol. With the purpose of producing stable and well defined nanocarriers, this work aims to determine the influence of different dose rates over protein nanoparticle formation. For this purpose, papain and BSA nanoparticles were synthetized in phosphate buffer (50 mM, pH 7.2) and ethanol (20-30%, v/v) using a radiation dose of 10 kGy and dose rate of 0.8, 2, 5 and 10 kGy.h-1. After irradiation, samples were evaluated by dynamic light scattering, fluorescence and proteolytic activity to verify the size, secondary structure and monitoring of the enzymatic activity, respectively. For papain nanoparticles it was observed that the dose rate did not influence the particle size formation, however crosslinking evidenced by bityrosine showed that samples irradiated at 0.8 and 5 kGy.h-1 presented higher bityrosine levels. On the other hand, BSA nanoparticles presented different results if compared to papain NPs. Different dose rates caused different and non-linear size increase for each condition, following the order: 5 > 10 > 0.8 > 2 kGy.h-1. However, in terms of crosslinking formation, a linear increase was registered, as at 0.8 kGy.h-1 the smallest signal was achieved, whereas at 10 kGy.h- 1 the highest signal was recorded. In conclusion, BSA nanoparticles were more sensitive to different radiation dose rates than nanopapain. Optimized results in terms of size increase and higher bityrosine levels were observed for the samples irradiated at 5 kGy.h-1, in which nanoparticle formation will occur faster if compared to the synthesis carried out under distinct conditions. As final applications of the system concert their use for the delivery of chemo or radiotherapeutics, the loading of paclitaxel, a well-known chemotherapeutic agent, and radiolabeling with tecntetium- 99m, a radioisotope suitable for biomedical applications, have also been performed with high efficiency, thus demonstrating a proof of concept of such systems.
Development of mucoadhesive PVA/CMC based hydrogel for intravesical chemotherapy
2018 - LIMA, C.S.A.; VARCA, J.O.; FERRARI, A.; NOGUEIRA, K.M.; VARCA, G.H.C.; LUGAO, A.B.
Bladder cancer (BC) is one of the main diseases that attack the urinary tract and is globally responsible for 165,000 deaths per year. Bladder tumor may be classified as non-muscle invasive (superficial) or muscle invasive. About 70% of patients present the superficial bladder cancer which is treated by transurethral resection for tumor removal followed by intravesical chemo or immunotherapy. The main challenge reported in the instillation of chemotherapy is the limited drug residence time in the bladder as a consequence of urine levels that leads to fast drug removal from the bladder.1 Hydrogels are chemically or physically crosslinked polymer systems that form three-dimensional networks with high water absorption capacity. Carboxymethylcellulose (CMC) is one of the major soluble derivatives of cellulose widely applied in the medical and pharmaceutical fields due to its biocompatibility, nontoxicity, biodegradability and film forming ability.2 Polyvinyl Alcohol (PVA) is a synthetic polymer with wide pharmaceutical and biomedical applications as it is nontoxic, non-carcinogenic, bioadhesive and easy to process.3 In this work, we developed a mucoadhesive hydrogel from a CMC and PVA polymer blend for chemotherapeutic loading and suitable rheological properties for intravesical instillation, especially designed for treating superficial BC with increased residence time of chemotherapeutic agent. Three formulations (C1, C2 and C3) at different CMC concentrations were prepared - 1%, 2% and 3% (w/v), respectively. PVA concentration corresponded to 1% (w/v) for all formulations. The polymers were separately solubilized in Milli-Q water and then mixed prior to the addition of 20% (v/v) glycerin to increase the mucoadhesiveness of the material. The hydrogels were characterized according to their organoleptic and rheological properties to evaluate the behavior of the material under tension and temperature. Accelerated stability tests of the pharmaceutical form were also performed. Comparatively, formulations with glycerin presented improved mucoadhesiveness, and formulations with 1 and 2% of CMC presented more adequate rheological behavior for the proposed application. In conclusions, the systems presented adequate properties for the delivery of chemotherapeutic agents for optimized BC treatments.
Development of lignin-PVP based dressing for wound treatment
2018 - NOGUEIRA, K.M.; VARCA, J.O.; VARCA, G.H.C.; LIMA, C.S.A.; LUGAO, A.B.
Lignin is a carbon renewable source and has been widely explored in different fields in the last years, especially in biomaterials as dressing and other biomedical devices due its natural origin and low cost1. Poly(ethylene oxide) (PEO) is a synthetic polymer largely used in biomedical applications due its important characteristics such as high hydrophilicity, non-toxicity and ease of process2. The present work aimed to develop a lignin-PEO based dressing for wound treatment by casting. In specific terms, three different polymer blends were formulated using a range of 3 to 10% (w/v) lignin was tested with the addition of 1 to 3% PEO. Lignin was solubilized in aqueous solution (pH>13) alkalized with sodium hydroxide and PEO was solubilized in distilled water. The solutions were heated up to 70 ºC and homogenized until complete polymer dissolution. Then, PEO solution and poly(ethylene glycol) diacrylate (PEGDA) (0.5 - 1.0%) were added to the lignin solution and the blend was mixed for 30 minutes at 70 ºC. Posteriorly the blends were submitted to casting and drying under different conditions, room temperature for 48 hours and incubated at 40 ºC for 24 hours. A control sample of 6% lignin was prepared in the same conditions. Samples were evaluated by physico-chemical and morphological characterizations. The swelling and gel fraction profiles were assessed as well as thermal behavior by differential scanning calorimetry. Chemical modifications were evaluated by infrared spectroscopy. Samples with higher PEGDA content presented minor swelling index. The blends formulated presented different thermal behavior in comparison with the control. Infrared spectroscopy pointed some chemical modifications promoted by the crosslinking agent. In general terms, the material developed presented a potential to continue been explored as dressing for wound treatment