Browsing by Author "Aguayo, Sebastian "

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    Antibacterial Effect of Honey-Derived Exosomes Containing Antimicrobial Peptides Against Oral Streptococci
    (2021) Leiva-Sabadini, Camila ; Alvarez, Simon ; Barrera, Nelson P.; Schuh, Christina M.A.P. ; Aguayo, Sebastian
    Purpose: Recently, our group found exosome-like extracellular vesicles (EVs) in Apis mellifera honey displaying strong antibacterial effects; however, the underlying mechanism is still not understood. Thus, the aim of this investigation was to characterize the molecular and nanomechanical properties of A. mellifera honey-derived EVs in order to elucidate the mechanisms behind their antibacterial effect, as well as to determine differential antibiofilm properties against relevant oral streptococci.
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    Aloe vera peel-derived nanovesicles display anti-inflammatory properties and prevent myofibroblast differentiation
    (2024) Ramirez, Orlando; Pomareda, Florencia; Olivares, Belen; Huang, Ya-Lin; Zavala, Gabriela; Carrasco-Rojas, Javiera; Alvarez, Simon; Leiva-Sabadini, Camila; Hidalgo, Valeria; Romo, Pablo; Sanchez, Matias; Vargas, Ayleen; Martinez, Jessica; Aguayo, Sebastian; Schuh, Christina M. A. P.
    Background: Aloe vera (AV) is a medicinal plant, most known for its beneficial effects on a variety of skin conditions. Its known active compounds include carbohydrates and flavonoids such as quercetin and kaempferol, among others. In the past decade, plant nanovesicles (NVs) have gained considerable interest as interkingdom communicators, presenting an opportunity for clinical standardization of natural products. In this study, we aimed to assess the potential of AVpNVs for the treatment of burn wounds.
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    Microfabrication-based engineering of biomimetic dentin-like constructs to simulate dental aging
    (2024) Alvarez, Simon; Morales, Jose; Tiozzo-Lyon, Paola; Berrios, Pablo; Barraza, Valentina; Simpson, Kevin; Ravasio, Andrea; Monforte Vila, Xavier; Teuschl-Woller, Andreas; Schuh, Christina M. A. P.; Aguayo, Sebastian
    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., Our study aimed to develop a novel in vitro microfabricated biomimetic dentin surface that simulates the complex surface microarchitecture of exposed dentin, as well as age-derived glycation of teeth, for the growth of polymicrobial oral biofilms.
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    Modulation of the biophysical and biochemical properties of collagen by glycation for tissue engineering applications
    (2023) Vaez, Mina; Asgari, Meisam; Hirvonen, Liisa; Bakir, Gorkem; Khattignavong, Emilie; Ezzo, Maya; Aguayo, Sebastian; Schuh, Christina M.; Gough, Kathleen; Bozec, Laurent
    The structural and functional properties of collagen are modulated by the presence of intramolecular and intermolecular crosslinks. Advanced Glycation End-products (AGEs) can produce intermolecular crosslinks by bonding the free amino groups of neighbouring proteins. In this research, the following hypothesis is explored: The accumulation of AGEs in collagen decreases its proteolytic degradation rates while increas-ing its stiffness. Fluorescence Lifetime Imaging (FLIM) and Fourier-transform infrared spectroscopy (FTIR) detect biochemical changes in collagen scaffolds during the glycation process. The accumulation of AGEs increases exponentially in the collagen scaffolds as a function of Methylglyoxal (MGO) concentration by performing autofluorescence measurement and competitive ELISA. Glycated scaffolds absorb water at a much higher rate confirming the direct affinity between AGEs and interstitial water within collagen fib-rils. In addition, the topology of collagen fibrils as observed by Atomic Force Microscopy (AFM) is a lot more defined following glycation. The elastic modulus of collagen fibrils decreases as a function of gly-cation, whereas the elastic modulus of collagen scaffolds increases. Finally, the enzymatic degradation of collagen by bacterial collagenase shows a sigmoidal pattern with a much slower degradation rate in the glycated scaffolds. This study identifies unique variations in the properties of collagen following the accumulation of AGEs.Statement of significanceIn humans, Advanced Glycation End-products (AGEs) are naturally produced as a result of aging process. There is an evident lack of knowledge in the basic science literature explaining the biomechanical impact of AGE-mediated crosslinks on the functional and structural properties of collagen at both the nanoscale (single fibrils) and mesoscale (bundles of fibrils). This research, demonstrates how it is possible to harness this natural phenomenon in vitro to enhance the properties of engineered collagen fibrils and scaffolds. This study identifies unique variations in the properties of collagen at nanoscale and mesoscale following accumulation of AGEs. In their approach, they investigate the unique properties conferred to collagen, namely enhanced water sorption, differential elastic modulus, and finally sigmoidal proteolytic degrada-tion behavior.(c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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    Pathogenesis-Guided Engineering: pH-Responsive Imprinted Polymer Co-Delivering Folate for Inflammation-Resolving as Immunotherapy in Implant-Related Infections
    (2024) Costa, Raphael C.; Nagay, Bruna E.; Villa, Javier E. L.; Sotomayor, Maria D. P. T.; Neres, Lariel Chagas da Silva; Benso, Bruna; Aguayo, Sebastian; Sacramento, Catarina M.; Ruiz, Karina G. S.; Spada, Fernanda P.; de Avila, Erica Dorigatti; da Costa, Monique G.; Faverani, Leonardo P.; Cintra, Luciano T. A.; Souza, Joao Gabriel S.; Barao, Valentim A. R.
    Folate (FT) is a suitable targeting ligand for folate receptors (FOLR) overexpressed on inflamed cells. Thus, FT-loaded polymers can be used as FOLRs-targeted immunotherapy to positively modulate the inflammatory process. A novel biodegradable imprinted polymer with a FT delivery mechanism driven by pH changes [PCL-MIP@FT] is designed with molecularly imprinted technology. The pH mechanism is validated in vitro, demonstrating that an acidic environment accelerated and increased the release of FT for a period of 7 days (similar to 100 mu g mL-1). For the first time, FT receptors (FOLR-1 and FOLR-3) are discovered and also overexpressed on activated human gingival fibroblasts, representing a favorable target in the oral environment. Although FT itself does not have antimicrobial effects, the nanomechanical properties of biofilm are changed after topical FT administration. In vivo systemic toxicity of PCL-MIP@FT has been demonstrated to be a safe biomaterial (up to 1.3 mg kg-1). When the PCL-MIP@FT is assessed in the subcutaneous tissue, it promoted an alleviating inflammation and may be able to stimulate tissue repair. The present findings have demonstrated the reliable in vitro and in vivo anti-inflammatory actions of FT-loaded polymer and support its use as a novel drug-free therapeutic platform for modulating and mitigating inflammatory responses in dental implant-related infections.