Barros, Caio H. N.
Barros, Caio H. N.
Barros, Caio H. N.
Now showing 1 - 3 of 3
- PublicationEnhancing curcumin's solubility and antibiofilm activity via silica surface modification(Royal Society of Chemistry, 2020-03-20)
; ; ; ; ;Bacterial biofilms are microbial communities in which bacterial cells in sessile state are mechanically andchemically protected against foreign agents, thus enhancing antibiotic resistance. The delivery of activecompounds to the inside of biofilms is often hindered due to the existence of the biofilm extracellularpolymeric substances (EPS) and to the poor solubility of drugs and antibiotics. A possible strategy toovercome the EPS barrier is the incorporation of antimicrobial agents into a nanocarrier, able topenetrate the matrix and deliver the active substance to the cells. Here, we report the synthesis ofantimicrobial curcumin-conjugated silica nanoparticles (curc-NPs) as a possibility for dealing with theseissues. Curcumin is a known antimicrobial agent and to overcome its low solubility in water it wasgrafted onto the surface of silica nanoparticles, the latter functioning as nanocarrier for curcumin intothe biofilm. Curc-NPs were able to impede the formation of modelP. putidabiofilms up to 50% anddisrupt mature biofilms up to 54% at 2.5 mg mL 1. Cell viability of sessile cells in both cases was alsoconsiderably affected, which is not observed for curcumin delivered as a free compound at the sameconcentration. Furthermore, proteomics of extracted EPS matrix of biofilms grown in the presence offree curcumin and curc-NPs revealed differences in the expression of key proteins related to celldetoxification and energy production. Therefore, curc-NPs are presented here as an alternative forcurcumin delivery that can be exploited not only to other bacterial strains but also to further biologicalapplications. 181Scopus© Citations 21
- PublicationSurface functionalization-dependent localization and affinity of SiO2 nanoparticles within the biofilm EPS matrix(Elsevier, 2020-12)
; ; ; ;The contribution of the biofilm extracellular polymeric substance (EPS) matrix to reduced antimicrobial sus-ceptibility in biofilms is widely recognised. As such, the direct targeting of the EPS matrix is a promising biofilmcontrol strategy that allows for the disruption of the matrix, thereby allowing a subsequent increase in suscep-tibility to antimicrobial agents. To this end, surface-functionalized nanoparticles (NPs) have received considerableattention. However, the fundamental understanding of the interactions occurring between engineered NPs andthe biofilm EPS matrix has not yet been fully elucidated. An insight into the underlying mechanisms involvedwhen a NP interacts with the EPS matrix will aid in the design of more efficient NPs for biofilm control. Here wedemonstrate the use of highly specificfluorescent probes in confocal laser scanning microscopy (CLSM) toillustrate the distribution of EPS macromolecules within the biofilm. Thereafter, a three-dimensional (3D)colocalization analysis was used to assess the affinity of differently functionalized silica NPs (SiNPs) and EPSmacromolecules fromPseudomonasfluorescensbiofilms. Results show that both the charge and surface functionalgroups of SiNPs dramatically affected the extent to which SiNPs interacted and localized with EPS macromole-cules, including proteins, polysaccharides and DNA. Hypotheses are also presented about the possible physico-chemical interactions which may be dominant in EPS matrix-NP interactions. This research not only develops aninnovative CLSM-based methodology for elucidating biofilm-nanoparticle interactions but also provides a plat-form on which to build more efficient NP systems for biofilm control. 118Scopus© Citations 15
- PublicationA Review of Nanomaterials and Technologies for Enhancing the Antibiofilm Activity of Natural Products and Phytochemicals(American Chemical Society, 2020-08-04)
;Biofilms are communities of microorganisms encased in a self-produced matrix constituted of extracellular polymeric substances (EPS). The recalcitrant and often harmful nature of biofilms, particularly in the biomedical field, motivates a search for antibiofilm compounds and materials. Within this context, nanoparticles (NPs) represent a promising platform for antibiofilm technologies due to their increased penetration into biofilms and facility of tailoring type, size, shape, and surface functionalization. The association of NPs with natural products and phytochemicals is even more appealing as an antibiofilm strategy, since the antimicrobial activity of essential oils, extracts, and isolated compounds can be improved when they are carried on the surface of NPs or encapsulated within them, as well as combined in formulations such as in nanoemulsions. This review article aims to provide an overview of recent methodologies for natural product delivery using nanomaterials and nanoformulations for the effective combat and eradication of bacterial and fungal biofilms. The nano-based technologies are categorized based on the type of antimicrobial delivery (NP coating, encapsulation, or nanoemulsions), and a selection of some widely reported natural substances (curcumin, propolis, and cinnamon components) is explored in more depth. 6Scopus© Citations 26