Nanoparticles for Signaling in Biodiagnosis and Treatment of Infectious Diseases

Abstract

Advances in nanoparticle-based systems constitute a promising research area with important implications for the treatment of bacterial infections, especially against multidrug resistant strains and bacterial biofilms. Nanosystems may be useful for the diagnosis and treatment of viral and fungal infections. Commercial diagnostic tests based on nanosystems are currently available. Different methodologies based on nanoparticles (NPs) have been developed to detect specific agents or to distinguish between Gram-positive and Gram-negative microorganisms. Also, biosensors based on nanoparticles have been applied in viral detection to improve available analytical techniques. Several point-of-care (POC) assays have been proposed that can offer results faster, easier and at lower cost than conventional techniques and can even be used in remote regions for viral diagnosis. Nanoparticles functionalized with specific molecules may modulate pharmacokinetic targeting recognition and increase anti-infective efficacy. Quorum sensing is a stimuli-response chemical communication process correlated with population density that bacteria use to regulate biofilm formation. Disabling it is an emerging approach for combating its pathogenicity. Natural or synthetic inhibitors may act as antibiofilm agents and be useful for treating multi-drug resistant bacteria. Nanostructured materials that interfere with signal molecules involved in biofilm growth have been developed for the control of infections associated with biofilm-associated infections.

Keywords: bacterial infections; nanoparticles; point-of-care testing; quorum sensing; signaling; viral infections.

Figure 1

Electrochemical aptasensor for the detection of E. coli O157:H7 [54]. Reproduced with permission.

Figure 2

Scheme of the capture by the binding affinity of the electrode sensor and the E. coli bacteria (a), nano-piercing process on the bacterial wall (b) membrane damage, (c) cytoplasm leakage and killing of the bacteria [58]. Reproduced with permission.

Figure 3

Schematic of the quorum sensing “Switch”, types of signal molecules and phenotypes. Autoinducers synthesis increases with bacteria population density (b) and when a thresthold level is achieved the response is activated (a) [134]. Reproduced with permission.

Figure 4

General scheme of quorum sensing in Gram-negative (A) and Gram-positive (B) bacteria [155]. Reproduced with permission.