Biogenic nanosilver against multidrug-resistant bacteria (MDRB)

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOMultidrug-resistant bacteria (MDRB) are extremely dangerous and bring a serious threat to health care systems as they can survive an attack from almost any drug. The bacteria’s adaptive way of living with the use of antimicrobials and antibiotics caused t73FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO2015/12534-52014/50867-3465389/20140

Nanoparticle–Biofilm Interactions: The Role of the EPS Matrix

The negative consequences of biofilms are widely reported. A defining feature of biofilms is the extracellular matrix, a complex mixture of biomacromolecules, termed EPS, which contributes to reduced antimicrobial susceptibility. EPS targeting is a promising, but underexploited, approach to biofilm control allowing disruption of the matrix and thereby increasing the susceptibility to antimicrobials. Nanoparticles (NPs) can play a very important role as ’carriers’ of EPS matrix disruptors, and several approaches have recently been proposed. In this review, we discuss the application of nanoparticles as antibiofilm technologies with a special emphasis on the role of the EPS matrix in the physicochemical regulation of the nanoparticle–biofilm interaction. We highlight the use of nanoparticles as a platform for a new generation of antibiofilm approaches.Science Foundation Irelan

Design of a tailored nanomaterial for sucrose capture and removal

Orientador: Ljubica TasicDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de QuímicaResumo: O diabetes é uma doença metabólica crônica que leva a elevados níveis de glicose no sangue, com consequências sérias para a saúde humana. Devido ao apelo mundial pela redução do consumo de calorias, propõe-se o desenvolvimento de um nanomaterial capaz de capturar a sacarose em soluções, que possa posteriormente ser avaliado para a remoção da sacarose naturalmente presente em alimentos como suco de laranja, disponibilizando, assim, alimentos de baixo teor calórico para consumo da população. Uma nanopartícula magnética (NPM-Fe3O4) revestida com material inerte (SiO2) e com uma enzima imobilizada (invertase), foi desenvolvida para reconhecer e capturar a sacarose. A síntese das NPM foi realizada pelo método de coprecipitação, ao passo que o recobrimento foi feito pelo método de Stöber. Obteve-se NPM com potencial zeta (?) de +28,7 ± 0,7 mV. A microscopia eletrônica de transmissão permitiu a identificação das NPM como uma população mista de esferas (27 ± 6 nm) e bastões (88 ± 22 nm x 14 ± 4 nm). A estrutura de espinélio do núcleo de magnetita foi confirmada pela difração de raios X. Por outro lado, a invertase extraída de fermento biológico seco e purificada por precipitação diferencial e etapas cromatográficas foi imobilizada nas NPM. Cerca de 13,5 mmol L-1 de sacarose foi removida por grama de nanomaterial por ciclo. A sacarose removida foi recuperada na forma de açúcar invertido, um subproduto com maior valor agregado. As NPM foram reutilizadas 5 vezes sem perda de atividade. A tecnologia desenvolvida permite a comercialização de alimentos com baixo valor calórico, oferecendo opções mais saudáveis para a população e ajudando a combater o crescimento da obesidade e do diabetes. Do ponto de vista econômico, ele abre novos mercados e oportunidades para a indústria de alimentos e agronegócios brasileira, maior exportadora de suco de laranja do mundoAbstract: Diabetes is a chronical metabolic disease which leads to high glucose levels in the blood, with grave consequences to human health. Due to the worldwide appeal for reducing calorie intake, it is proposed the design of a nanomaterial capable to capture sucrose from solutions, which could be employed in the removal of naturally occurring sucrose from food, such as orange juice, producing a low-calorie juice. Magnetic nanoparticles (Fe3O4 NPs) coated with an inert material (SiO2), with an immobilized enzyme (invertase) capable to recognize and capture the sucrose from a solution were designed to optimize the separation step. The nanoparticles were obtained by the co-precipitation method, whereas the coating was done by the Stöber method. Fe3O4 NPs with a zeta potential of +28.7 ± 0.7 mV were obtained. Transmission Electron Microscopy allowed the identification of a mixed population of spheres (27 ± 6 nm) and rods (88 ± 22 nm x 14 ± 4 nm). The structure of the magnetite, inverted spinel, was confirmed by X-ray diffraction. Furthermore, invertase extracted from baker¿s yeast and purified by differential precipitation and chromatography and was immobilized onto Fe3O4 surface. Approximately 13.5 mmol L-1 of sucrose was removed per gram of nanomaterial per cycle. Sucrose was recovered in the form of inverted sugar, a side product with higher market value. The nanomaterial was reused 5 times without any activity loss. The developed technology allows the commercialization of low-calorie food, offering healthier options to consumers and helping to fight diabetes and obesity. From an economic point of view, it opens new markets and opportunities to the Brazilian food and agribusiness industries, the biggest exporter of orange juice in the worldMestradoQuímica OrgânicaMestra em Química130957/2016-0CNP

Magnetic Nanomaterials as Biocatalyst Carriers for Biomass Processing: Immobilization Strategies, Reusability, and Applications

Environmental concerns, along with oil shortages, have increased industrial interest in biomass conversion to produce biofuels and other valuable chemicals. A green option in biomass processing is the use of enzymes, such as cellulases, hemicellulases, and ligninolytic (laccase and peroxidases), which have outstanding specificity toward their substrates and can be reused if immobilized onto magnetic nanocarriers. Numerous studies report the biocatalysts’ performance after covalent binding or adsorption on differently functionalized magnetic nanoparticles (MNPs). Functionalization strategies of MNPs include silica-based surfaces obtained through a sol–gel process, graphene oxide-based nanocomposites, polymer-coated surfaces, grafting polymer brushes, and others, which have been emphasized in this review of the immobilization and co-immobilization of enzymes used for biomass conversion. Careful analysis of the parameters affecting the performance of enzyme immobilization for new hybrid matrices has enabled us to achieve wider tolerance to thermal or chemical stress by these biosystems during saccharification. Additionally, it has enabled the application of immobilized laccase to remove toxic organic compounds from lignin, among other recent advances addressed here related to the use of reusable magnetic carriers for bioderived chemical manufacturing

Biogenic Nanosilver against Multidrug-Resistant Bacteria (MDRB)

Multidrug-resistant bacteria (MDRB) are extremely dangerous and bring a serious threat to health care systems as they can survive an attack from almost any drug. The bacteria’s adaptive way of living with the use of antimicrobials and antibiotics caused them to modify and prevail in hostile conditions by creating resistance to known antibiotics or their combinations. The emergence of nanomaterials as new antimicrobials introduces a new paradigm for antibiotic use in various fields. For example, silver nanoparticles (AgNPs) are the oldest nanomaterial used for bactericide and bacteriostatic purposes. However, for just a few decades these have been produced in a biogenic or bio-based fashion. This review brings the latest reports on biogenic AgNPs in the combat against MDRB. Some antimicrobial mechanisms and possible silver resistance traits acquired by bacteria are also presented. Hopefully, novel AgNPs-containing products might be designed against MDR bacterial infections

Interactions between functionalised silica nanoparticles and Pseudomonas fluorescens biofilm matrix: A focus on the protein corona.

Biofilms are microbial communities embedded in an extracellular polymeric matrix and display an enhanced tolerance to the action of antimicrobials. The emergence of novel functionalised nanoparticles is considered a promising avenue for the development of biofilm-specific antimicrobial technologies. However, there is a gap in the understanding of interactions between nanoparticles and the biofilm matrix. Particularly, questions are raised on how nanoparticle charge and surface groups play a role in aggregation when in contact with biofilm components. Herein we present the synthesis of four types of silica nanoparticles and undertake an analysis of their interactions with Pseudomonas fluorescens biofilm matrix. The effect of the biofilm matrix components on the charge and aggregation of the nanoparticles was assessed. Additionally, the study focused on the role of matrix proteins, with the in-depth characterisation of the protein corona of each nanoparticle by Liquid Chromatography with Tandem Mass Spectrometry experiments. The protein corona composition is dependent on the nanoparticle type; non-functionalised nanoparticles show less protein selectivity, whereas carboxylate-functionalised nanoparticles prefer proteins with a higher isoelectric point. These outcomes provide insights into the field of biofilm-nanoparticle interactions that can be valuable for the design of new nano-based targeting systems in future anti-biofilm applications

Tailoring Nanoparticle-Biofilm Interactions to Increase the Efficacy of Antimicrobial Agents Against Staphylococcus aureus

Background: Considering the timeline required for the development of novel antimicrobial drugs, increased attention should be given to repurposing old drugs and improving anti-microbial efficacy, particularly for chronic infections associated with biofilms. Methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) are common causes of biofilm-associated infections but produce different biofilm matrices.MSSA biofilm cells are typically embedded in an extracellular polysaccharide matrix, whereas MRSA biofilms comprise predominantly of surface proteins and extracellular DNA (eDNA). Nanoparticles (NPs) have the potential to enhance the delivery of antimicro-bial agents into biofilms. However, the mechanisms which influence the interactions between NPs and the biofilm matrix are not yet fully understood. Methods:To investigate the influence of NPs surface chemistry on vancomycin (VAN) encapsulation and NP entrapment in MRSA and MSSA biofilms, mesoporous silica nano-particles (MSNs) with different surface functionalization (bare-B, amine-D, carboxyl-C,aromatic-A) were synthesised using an adapted Stöber method. The antibacterial efficacy of VAN-loaded MSNs was assessed against MRSA and MSSA biofilms. Results: The two negatively charged MSNs (MSN-B and MSN-C) showed a higher VAN loading in comparison to the positively charged MSNs (MSN-D and MSN-A). Cellular binding with MSN suspensions (0.25 mg mL−1) correlated with the reduced viability of both MSSA andMRSA biofilm cells. This allowed the administration of low MSNs concentrations while maintaining a high local concentration of the antibiotic surrounding the bacterial cells. Conclusion: Our data suggest that by tailoring the surface functionalization of MSNs,enhanced bacterial cell targeting can be achieved, leading to a novel treatment strategy for biofilm infections.Science Foundation Irelan

Synthesis and self-assembly of curcumin-modified amphiphilic polymeric micelles with antibacterial activity

Background: The ubiquitous nature of bacterial biofilms combined with the enhanced resistance towards antimicrobials has led to the development of an increasing number of strategies for biofilm eradication. Such strategies must take into account the existence of extracellular polymeric substances, which obstruct the diffusion of antibiofilm agents and assists in the maintenance of a well-defended microbial community. Within this context, nanoparticles have been studied for their drug delivery efficacy and easily customised surface. Nevertheless, there usually is a requirement for nanocarriers to be used in association with an antimicrobial agent; the intrinsically antimicrobial nanoparticles are most often made of metals or metal oxides, which is not ideal from ecological and biomedical perspectives. Based on this, the use of polymeric micelles as nanocarriers is appealing as they can be easily prepared using biodegradable organic materials. Results: In the present work, micelles comprised of poly(lactic-co-glycolic acid) and dextran are prepared and then functionalised with curcumin. The effect of the functionalisation in the micelle's physical properties was elucidated, and the antibacterial and antibiofilm activities were assessed for the prepared polymeric nanoparticles against Pseudomonas spp. cells and biofilms. It was found that the nanoparticles have good penetration into the biofilms, which resulted in enhanced antibacterial activity of the conjugated micelles when compared to free curcumin. Furthermore, the curcumin-functionalised micelles were efficient at disrupting mature biofilms and demonstrated antibacterial activity towards biofilm-embedded cells. Conclusion: Curcumin-functionalised poly(lactic-co-glycolic acid)-dextran micelles are novel nanostructures with an intrinsic antibacterial activity tested against two Pseudomonas spp. strains that have the potential to be further exploited to deliver a secondary bioactive molecule within its core.</p

Cross-species communication via agr controls phage susceptibility in Staphylococcus aureus

Summary: Bacteria use quorum sensing (QS) to coordinate group behavior in response to cell density, and some bacterial viruses (phages) also respond to QS. In Staphylococcus aureus, the agr-encoded QS system relies on accumulation of auto-inducing cyclic peptides (AIPs). Other staphylococci also produce AIPs of which many inhibit S. aureus agr. We show that agr induction reduces expression of tarM, encoding a glycosyltransferase responsible for α-N-acetylglucosamine modification of the major S. aureus phage receptor, the wall teichoic acids. This allows lytic phage Stab20 and related phages to infect and kill S. aureus. However, in mixed communities, producers of inhibitory AIPs like S. haemolyticus, S. caprae, and S. pseudintermedius inhibit S. aureus agr, thereby impeding phage infection. Our results demonstrate that cross-species interactions dramatically impact phage susceptibility. These interactions likely influence microbial ecology and impact the efficacy of phages in medical and biotechnological applications such as phage therapy

NMR insights on nano silver post-surgical treatment of superficial caseous lymphadenitis in small ruminants

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCaseous lymphadenitis (CL), caused by a pathogen of the second class of biosafety – Corynebacterium pseudotuberculosis, is a chronic and severe infectious disease that affects small ruminants and requires long, ineffective treatment which generally leads8714077840786FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO2015/12534-52018/06510-42014/18938-8sem informaçãosem informaçã