Sensor impedimétrico para la detección de bacterias patogénicas mediante péptidos antimicrobianos

Áccesit Congreso SIBB 2015La peri-implantitis, una inflamación causada por la formación del biofilm, es una de las causas más importantes de la fallida de los implantes en odontología. Por esto, la detección de bacterias patogénicas al inicio del proceso de formación de biofilms, representa una estrategia muy potente para la prevención de las infecciones en los implantes. Entre los diferentes métodos para la detección de bacterias patogénicas, los biosensores electroquímicos, especialmente los sistemas basados en impedancia (EIS), presentan una serie de ventajas como la miniaturización, la mejora en sensibilidad y el bajo coste. En este sentido, los péptidos antimicrobianos (AMPs), conocidos como componentes del sistema inmune y con actividad hacia las bacterias, pueden ser usados para desarrollar elementos de bioreconocimiento altamente efectivos. Por lo tanto, el objetivo de este estudio es la combinación del uso de EIS y la habilidad de los AMPs para obtener biosensores con alta sensibilidad, especificidad y límites de detección muy bajos para la detección de bacterias patogénicas.Peer ReviewedAward-winnin

Antibacterial approaches in tissue engineering using metal ions and nanoparticles: From mechanisms to applications

Bacterial infection of implanted scaffolds may have fatal consequences and, in combination with the emergence of multidrug bacterial resistance, the development of advanced antibacterial biomaterials and constructs is of great interest. Since decades ago, metals and their ions had been used to minimize bacterial infection risk and, more recently, metal-based nanomaterials, with improved antimicrobial properties, have been advocated as a novel and tunable alternative. A comprehensive review is provided on how metal ions and ion nanoparticles have the potential to decrease or eliminate unwanted bacteria. Antibacterial mechanisms such as oxidative stress induction, ion release and disruption of biomolecules are currently well accepted. However, the exact antimicrobial mechanisms of the discussed metal compounds remain poorly understood. The combination of different metal ions and surface decorations of nanoparticles will lead to synergistic effects and improved microbial killing, and allow to mitigate potential side effects to the host. Starting with a general overview of antibacterial mechanisms, we subsequently focus on specific metal ions such as silver, zinc, copper, iron and gold, and outline their distinct modes of action. Finally, we discuss the use of these metal ions and nanoparticles in tissue engineering to prevent implant failure

Biological Roles and Delivery Strategies for Ions to Promote Osteogenic Induction

Bone is the most studied tissue in the field of tissue regeneration. Even though it has intrinsic capability to regenerate upon injury, several pathologies and injuries could hamper the highly orchestrated bone formation and resorption process. Bone tissue engineering seeks to mimic the extracellular matrix of the tissue and the different biochemical pathways that lead to successful regeneration. For many years, the use of extrinsic factors (i.e., growth factors and drugs) to modulate these biological processes have been the preferred choice in the field. Even though it has been successful in some instances, this approach presents several drawbacks, such as safety-concerns, short release profile and half-time life of the compounds. On the other hand, the use of inorganic ions has attracted significant attention due to their therapeutic effects, stability and lower biological risks. Biomaterials play a key role in such strategies where they serve as a substrate for the incorporation and release of the ions. In this review, the methodologies used to incorporate ions in biomaterials is presented, highlighting the osteogenic properties of such ions and the roles of biomaterials in controlling their release.</p

Widespread diversity deficits of coral reef sharks and rays

A global survey of coral reefs reveals that overfishing is driving resident shark species toward extinction, causing diversity deficits in reef elasmobranch (shark and ray) assemblages. Our species-level analysis revealed global declines of 60 to 73% for five common resident reef shark species and that individual shark species were not detected at 34 to 47% of surveyed reefs. As reefs become more shark-depleted, rays begin to dominate assemblages. Shark-dominated assemblages persist in wealthy nations with strong governance and in highly protected areas, whereas poverty, weak governance, and a lack of shark management are associated with depauperate assemblages mainly composed of rays. Without action to address these diversity deficits, loss of ecological function and ecosystem services will increasingly affect human communities

Delaying surgery for patients with a previous SARS-CoV-2 infection

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Selectivity of antimicrobial peptides: a complex interplay of multiple equilibria

Antimicrobial peptides (AMPs) attack bacterial membranes selectively, killing microbes at concentrations that cause no toxicity to the host cells. This selectivity is not due to interaction with specific receptors, but is determined by the different lipid composition of the membranes of the two cell types, and by the peculiar physico-chemical properties of AMPs, particularly their cationic and amphipathic character. However, the available data, including recent studies of peptide-cell association, indicate that this picture is excessively simplistic, because selectivity is modulated by a complex interplay of several interconnected phenomena. For instance, conformational transitions and self-assembly equilibria modulate the effective peptide hydrophobicity, the electrostatic and hydrophobic contributions to the membrane binding driving force are non-additive, and kinetic processes can play an important role in selective bacterial killing in the presence of host cells. All these phenomena, and their bearing on the final activity and toxicity of AMPs, must be considered in the definition of design principles to optimize peptide selectivity