18 research outputs found

    Fucoidan immobilized at the surface of a fibrous mesh presents toxic effects over melanoma cells, but not over non-cancer skin cells

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    The use of fucoidan, a marine-origin bioactive polymer, is herein proposed as a component of an innovative and effective strategy against melanoma, one of the most aggressive skin cancers. First, fucoidan antitumor activity, in its soluble form, was assessed presenting increased cytotoxicity over melanoma cells when compared to human dermal fibroblasts and keratinocytes. After this antitumor activity validation and trying to develop a more targeted and local strategy aiming to diminish the cytotoxic effects over noncancer cells, fucoidan was immobilized at the surface of an electrospun nanofiber mesh (NFM_Fu), envisioning the development of a therapeutic patch. The maximum immobilization concentration was 1.2 mg mLâ 1, determined by the Toluidine Blue Assay and confirmed by XPS. Furthermore, NFM_Fu is more hydrophilic than NFM, presenting a contact angle of 36°, lower than the 121° of the control condition. NFM_Fu was able to reduce human melanoma cell viability by 50% without affecting human dermal fibroblasts and keratinocytes. Taken together, these results set the basis for a valuable approach for melanoma treatment.This work was developed under the scope of the Structured Projects for R&D&I NORTE-01-0145-FEDER-000021 and NORTE-01-0145-FEDER-000023 supported by the Northern Portugal Regional Operational Programme (NORTE 2020),under the Portugal 2020 Partnership Agreement. The authors would like also to thank NORTE 2020 for financing the Ph.D.scholarship of C.O.“Norte-08-5369-000037”and the Portuguese Foundation for Science and Technology for the Investigator Grant of A.M. (IF/00376/2014). Dr. Luísa Rodrigues is acknowledged by the XPS analysis

    Self-assembling Peptide for HIV-1 Vaccine Design

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    Human immunodeficiency virus-1 (HIV-1) is a worldwide epidemic, which cannot be eliminated by any current therapeutics, even with highly active antiretroviral therapy, which only can control virus replication. A safe and effective vaccine against HIV-1 that can elicit both potent humoral and cellular responses has been considered a best solution to prevent the infection or to reduce the viral load. However, despite the fact that over 250 clinical trials have been conducted based on different concepts, no vaccine has been successfully developed. The extraordinary diversity of HIV-1, the capability of the virus to escape from the adaptive immunity, the difficulty in inducing broadly neutralizing antibodies, and the lack of clear immune correlates of protection represent the major challenges obstructing the development of HIV-1 vaccines. Designing a peptide-based vaccine that stimulates cytotoxic T lymphocytes (CTLs) specifically against the highly conserved epitopes in HIV-1 has been considered a promising strategy. This can provide two theoretical advantages: maximizing the immunological coverage and minimizing the viral escape from recognition of T cells. However, owning to the short sequence (normally 8-10 amino acids for CTL epitopes), these conserved epitopes are weakly immunogenic, requiring potent adjuvants to boost the efficiency. Some novel strategies have been reported to achieve an efficient adjuvant without causing any side effect. Among them, nanoparticle based delivery systems that can provide targeted delivery to immune cells and/or self-adjuvant effect, are emerging as a promising approach. In this thesis, we present a self-assembling peptide based delivery platform efficiently integrating antigenic peptides and immune potentiators in the formulation of a nanoparticle vaccine, and evaluate the immunogenicity in vitro and in vivo. Three parts are involved in this work: (1) feasibility study of the delivery of HIV-1 CTL epitope with the self-assembling peptide EAK16-II (sequence: AEAEAKAKAEAEAKAK) and the cross-presentation efficiency by dendritic cells (DCs); (2) co-delivery of an antigenic peptide and a toll like receptor (TLR) agonist within one nanoparticle to target and maturate DCs, leading to enhanced CTL response; (3) formulating a prophylactic peptide vaccine against HIV-1 by the combination of CD4 epitope-conjugated EAK16-II, CD8 epitope-conjugated EAK16-II, and a TLR agonist R848, which was subsequently assessed the immunogenicity in the transgenic mice. The peptide EAK16-II could self-assemble into nanofibers, which were stable in the acidic environment and in the presence of proteases. We hypothesized that by directly conjugating HIV-1 CD8 epitope with EAK16-II, the fibrillar structures of the conjugate would enhance the stability of epitope and thus improve the immunogenicity. To verify this, the CD8 epitope SL9 was conjugated with EAK16-II to obtain the epitope-loading peptide SL9-EAK16-II. Physicochemical characterizations revealed SL9-EAK16-II spontaneously assembled to short nanofibers in PBS, which were more stable in serum or oligopeptidase than unstructured SL9. Ex-vivo generated DCs that were pulsed with SL9-EAK16-II and activated by maturation cytokines, stimulated more poly-functional CD8+ T cells. This augment was explained by the evidence that SL9-EAK16-II was degraded more slowly than SL9 within DCs, therefore prolonging the stimulation to CD8 T cells. Moreover, the results from confocal microscopy suggested the cytosolic pathway for the cross-presentation of SL9-EAK16-II. However, SL9-EAK16-II itself failed to maturate DCs after internalization, which might cause antigen tolerance. To avoid the induction of tolerance and further enhance the antigenicity of epitope SL9, TLR agonist R837 or R848 was incorporated into the nanofiber formulation. The data from fluorescence spectra and calorimetric titration suggested the co-assembly between SL9-loaded nanofibers and TLR agonist was mainly driven by hydrogen bonding and hydrophobic interactions. The SL9-EAK16-II/R848 co-assemblies strongly facilitated the activation of DCs, and stimulated significantly more epitope specific CTLs when assessed in the form of DC based vaccine. The in vitro studies implied the potential of the self-assembling peptide EAK16-II as a nanocarrier in the formulation of vaccine. We further determined the applicability of this formulation in vivo. Since the activation of CD4+T cells plays a critical role in the generation of functional memory CTLs, we incorporated an additional CD4 epitope TL13 into the vaccine formulation, via conjugating with EAK16-II. The new formulation of antigen was characterized as nanofibers with average size of approximately 220 nm. The transgenic mice that were subcutaneously injected with these nanofibers produced as much as 1 fold increase in frequencies of SL9 specific CTLs, when compared with the mice vaccinated with either the mixture of epitopes and R848, or R848 alone. Moreover, almost 90% of the SL9 specific CTLs primed by the nanofibers were central memory CD8+ T cells (CD44+, CD62L+), which was the hallmark of the acquired immune response. The in-vivo study suggested not only enhanced magnitude, but also higher quality of T cell response was induced by the nanoparticle-based vaccine. Our findings demonstrated the self-assembling peptide had considerable promise as a delivery platform to integrate the principal components for cellular response-focusing vaccines

    Multifunctional Polydopamine Nanomaterials for Biomedical and Environmental Applications

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    Polydopamine (PDA), a synthetic and organic material, has emerged as a promising materialplatform for various applications in energy, environmental, and biomedical fields. PDA, formed by self-polymerization of dopamine, is rich in catechol and amine groups, which facilitate covalent conjugation and/or other non-covalent interactions with organic and inorganic materials. It is highly biocompatible, biodegradable, has broadband light absorption spectrum and excellent light-to-heat conversion efficiency. Also, it is easy to synthesize and functionalize. The combination of excellent characteristics of polydopamine-based nanomaterials, make them a promising adsorbent agent for environmental wastewater treatment and photothermal agent for biomedical applications. In the first half of thesis, we utilize the surface chemical functionality of polydopamine nanoparticles and their affinity to heavy metal ions and organic dyes to realize multifunctional filtration membranes that remove heavy metal ions and organic dyes from water through adsorption and catalytic degradation. Polydopamine exhibits high adsorption capacity toward heavy metal ions and organic dyes. Adsorption-based membrane technologies can be ideal for continuous flow water purification and have been extensively employed at industrial scale forxxiii water reclamation. By introducing polydopamine nanoparticles during bacteria-mediated cellulose growth, we fabricated a composite foam and membrane to study the adsorption behavior of the nanocomposites in different environmentally relevant pH and concentrations. The PDA/BNC membrane was used to investigate the removal efficiency of toxic heavy metals ions such as Pb (II) and Cd (II) and organic pollutants such as rhodamine 6G and methylene blue. Furthermore, to improve the range of pH in which the composite membrane is effective for dye removal, we fabricated another novel polydopamine/nanocellulose membrane, which is decorated with palladium (Pd) nanoparticles to remove organic dyes from contaminated water through catalytic dye degradation. In the second part of thesis, we develop polydopamine-based nanomaterials and experimental setups to be used in biomedical applications such as drug delivery and photothermal stimulation of cells. Using mesoporous silica-coated PDA nanoparticles as drug carrier and tetradecanol (TD) as gate keeper, we demonstrated that we could enhance the immune system response toward Melanoma cancer in mouse model through combination of photothermal and immunotherapy. Polydopamine core works as a photothermal agent to cause localized release of gardiquimod and tumor cell death upon NIR laser irradiation, hence, release of tumor associated antigens. Antigen presenting cells (APCs) including the dendritic cells and macrophages uptake these antigens and be activated around tumor site in response to these signals. Furthermore, these activated APCs, present the antigen to CD8+ cytotoxic T cells to actuate anti-tumor immune response. We have shown that this treatment is effective in reducing the tumor size and eliminating it in majority of cases. Also, the treatment created a memory effect in immune system toward melanoma cancer when second cancer event happened in mice that were treated before. Finally, we investigated the possibility of controlling the excitable cells’ activity through nanoheating. This was made possible by using polydopamine nanoparticles to localize the heat on cell membrane. We demonstrated that by using polydopamine nanoparticle and polydopamine/collagen 3D foam, and by applying NIR laser light, we can reversibly modulate the activity of in vitro cultured neurons and cardiomyocytes. A reduction in firing rate of neurons and an increase in beating rate of cardiomyocytes with different degree of inhibition and excitation was observed. Effect of different parameters on the quality of modulation was investigated

    Rancang Bangun Sistem Kontrol Jarum Spinneret dan Kolektor pada Electrospinning

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    Teknologi nano telah banyak dikembangkan dalam dunia industri di Indonesia. Salah satu hasil teknologi nano yang banyak diaplikasikan dalam kehidupan yaitu nanofiber. Nanofiber banyak digunakan dalam beberapa bidang, diantaranya yaitu dalam bidang filtrasi air, energi, kesehatan dan lain-lain. Salah satu metode pembuatan nanofiber yang paling mudah dan murah yaitu dengan cara electrospinning. Electrospinning memanfaatkan sumber tegangan tinggi dalam pembuatan nanofiber. Parameter yang mempengaruhi diameter dan sebaran fiber diantaranya yaitu kecepatan dan jarak gerak jarum spinneret serta kecepatan rotasi kolektor. Penelitian ini dilakukan untuk merancang dan membuat sistem pengontrol gerak kolektor dan jarum spinneret pada electrospinning. Motor stepper dan driver A4988 digunakan untuk mengontrol kecepatan dan jarak gerak jarum spinneret. Motor DC 12V dan driver L293D digunakan untuk mengontrol arah dan kecepatan putar kolektor. Kontrol kecepatan kolektor menggunakan prinsip Pulse Width Modulation (PWM). Sistem kontrol yang telah dibuat mempunyai tingkat keakuratan lebih dari 95%. Electrospinning yang telah dibuat dapat digunakan untuk memproduksi nanofiber. ====================================================================================================== Nanotechnology has been greatly developed in Indonesian Industrial Technology one of the example is the nanofiber. Nanofiber acts in several aspects of industries such as water filtration, energy and medical applications etc. one of the cheapest and easiest nanofiber extraction is electrospinning. Electrospinning uses the high DC voltage to generate the nanofiber. The affected parameters in nanofiber diameter and fiber spreading area are the speed and distance of spinneret also the rotation speed of the collector. This investigation aims to design and create the control system of spinneret needle and collector. The speed control and needle distance is performed by the A4988 and motor stepper. The DC 12V motor and L293D driver are used to control the direction and rotational speed of collector. The collector control speed is based on Pulse width modulation principle. This control system is proven to be have high accuracy with more than 95%. The constructed electrospinning can be used in nanofiber production

    Nanomedicine Approaches to Negotiate Local Biobarriers for Topical Drug Delivery

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    AbstractTopical treatments have been widely adopted to address a broad range of conditions across multiple sites thanks to their convenience, versatility, and effectiveness. While bypassing systemic biobarriers and avoiding systemic side effects by delivering directly to the target tissue, topical treatments still face significant local biobarriers that limit their efficacy. The toolset available for nanodelivery systems and their inherent multifunctionality can contribute to simultaneously address otherwise intractable challenges related to barrier function evasion, drug solubility, bioavailability, pharmacokinetics, smart and sustained release, quantitative co‐delivery, and local targeting which are key to successful topical treatments. This review summarizes the outstanding challenges associated with the topical treatments of key diseases of the skin, mucosae, eyes, and ears, and highlights how nanodelivery systems are being developed to address them effectively

    Development of new in vitro models based on the use of electrospun scaffolds and their imaging by multiphoton microscopy coupled with fluorescence lifetime imaging microscopy

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    2016 - 2017In this thesis, new possible applications of electrospun scaffolds are presented. Besides, the interaction of human dermal fibroblasts (HDFs) with the materials has been investigated using multiphoton microscopy (MPM) coupled with fluorescence lifetime imaging microscopy (FLIM), using a non-invasive, marker-free approach. In the first part of the thesis, pure poly-L-lactide (PLA) scaffolds were obtained and characterized as delivery systems for Diclofenac sodium salt (DCF) and a synthetically obtained prodrug of it for the treatment of actinic keratosis. The Diclofenac prodrug was obtained via solid phase peptide synthesis using a versatile, clean, high yielding procedure. Besides, the drug encapsulation and its release from the scaffold could be imaged using MPM. Moreover, when working with the unmodified DCF we were able to control the release profile by adding small amounts of dimethyl sulfoxide. The DCF-loaded scaffold was used as a delivery system to induce in vitro cell death in HDFs. The target cells were imaged using MPM coupled with FLIM, using a non-invasive, marker-free in vitro model to investigate drug effects. In the last part of the thesis, we produced and characterized different hybrid gelatin/PLA scaffolds. In this case, the goal was to obtain well-blended scaffolds with tunable properties, such as porosity, hydrophobicity and wettability... [edited by Author]XXX cicl

    Literature-based discovery of known and potential new mechanisms for relating the status of cholesterol to the progression of breast cancer

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    Breast cancer has been studied for a long period of time and from a variety of perspectives in order to understand its pathogeny. The pathogeny of breast cancer can be classified into two groups: hereditary and spontaneous. Although cancer in general is considered a genetic disease, spontaneous factors are responsible for most of the pathogeny of breast cancer. In other words, breast cancer is more likely to be caused and deteriorated by the dysfunction of a physical molecule than be caused by germline mutation directly. Interestingly, cholesterol, as one of those molecules, has been discovered to correlate with breast cancer risk. However, the mechanisms of how cholesterol helps breast cancer progression are not thoroughly understood. As a result, this study aims to study known and discover potential new mechanisms regarding to the correlation of cholesterol and breast cancer progression using literature review and literature-based discovery. The known mechanisms are further classified into four groups: cholesterol membrane content, transport of cholesterol, cholesterol metabolites, and other. The potential mechanisms, which are intended to provide potential new treatments, have been identified and checked for feasibility by an expert

    Advances in Hydrogels

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    Hydrogels are a class of soft materials with crosslinked network structures. They show good biocompatibility, biodegradability, hydrophilicity, and mechanical properties similar to those of tissue, so they have a wide range of applications. In recent years, a variety of multifunctional hydrogels with excellent performance have been developed, greatly expanding the depth and breadth of their applications. This book is the reprint of the Special Issue “Advances in Hydrogels”, which focused on the recent advances regarding hydrogels, aiming to provide reference for researchers in related fields. This book included one editorial, thirteen original research articles, and three valuable reviews from thirteen different countries including Canada, China, Thailand, Mexico, India, Saudi Arabia, Chile, Germany, the Czech Republic, Colombia, Romania, Israel, and the USA

    2019 Oklahoma Research Day Full Program

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    Oklahoma Research Day 2019 - SWOSU Celebrating 20 years of Undergraduate Research Successes
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