Public awareness of infectious diseases has increased in recent months, not only due to the current COVID-19 outbreak but also because of antimicrobial resistance (AMR) being declared a top-10 global health threat by the World Health Organization (WHO) in 2019. These global issues have spiked the realization that new and more efficient methods and approaches are urgently required to efficiently combat and overcome the failures in the diagnosis and therapy of infectious disease. This holds true not only for current diseases, but we should also have enough readiness to fight the unforeseen diseases so as to avoid future pandemics. A paradigm shift is needed, not only in infection treatment, but also diagnostic practices, to overcome the potential failures associated with early diagnosis stages, leading to unnecessary and inefficient treatments, while simultaneously promoting AMR. With the development of nanotechnology, nanomaterials fabricated as multifunctional nano-platforms for antibacterial therapeutics, diagnostics, or both (known as “theranostics”) have attracted increasing attention. In the research field of nanomedicine, mesoporous silica nanoparticles (MSN) with a tailored structure, large surface area, high loading capacity, abundant chemical versatility, and acceptable biocompatibility, have shown great potential to integrate the desired functions for diagnosis of bacterial infections. The focus of this review is to present the advances in mesoporous materials in the form of nanoparticles (NPs) or composites that can easily and flexibly accommodate dual or multifunctional capabilities of separation, identification and tracking performed during the diagnosis of infectious diseases together with the inspiring NP designs in diagnosis of bacterial infections.

Core@shell structured nanocomposites have received significant attention for providing a combinatory antibacterial mode of action. A rational identification of the accommodated unit’s role in the core@shell nanostructure is needed in order to solidify whether antibacterial synergism could be provided within the same core-shell structure against bacterial cell growth. Herein, a novel nanostructure(s) composed of a cerium oxide core and a porous silica shell (CeO2@pSiO2) with curcumin and lectin accommodation was prepared, and the antibacterial synergism provided by the nanocomposite was identified. The resulting spherical-shaped nanostructure CeO2@pSiO2 allowed the accommodation of curcumin loading (9 w/w%) and lectin (concanavalin A) coating (15 w/w%). The antibacterial synergism was tested using a minimal inhibitory concentration assay against Escherichia coli gram-negative bacterial strain. Furthermore, the bacterial cell disruption mechanisms induced by the curcumin-loaded and concanavalin A-coated CeO2@pSiO2 core@shell structure, namely the nanoantibiotic (nano-AB) and its design components were identified individually. Our findings revealed that mesoporous silica shell around the cerium oxide core within the nano-AB design aiding the accommodation of curcumin and concanavalin A promoted the destruction of the motility of the bacterial cells and the permeability of the inner and outer bacterial cell membranes. Our findings strongly indicate the promising potential of a mesoporous silica shell around cerium oxide core nanoparticles to provide synergistic antibacterial treatment and attack the bacterial cells by different action mechanisms.