Decorating CdTe QD-Embedded Mesoporous Silica Nanospheres with Ag NPs to Prevent Bacteria Invasion for Enhanced Anticounterfeit Applications

Abstract

Quantum dots (QDs) as potent candidates possess advantageous superiority in fluorescence imaging applications, but they are susceptible to the biological circumstances (e.g., bacterial environment), leading to fluorescence quenching or lose of fluorescent properties. In this work, CdTe QDs were embedded into mesoporous silica nanospheres (m-SiO2 NSs) for preventing QD agglomeration, and then CdTe QD-embedded m-SiO2 NSs (m-SiO2/CdTe NSs) were modified with Ag nanoparticles (Ag NPs) to prevent bacteria invasion for enhanced anticounterfeit applications. The m-SiO2 NSs, which serve as intermediate layers to combine CdTe QDs with Ag NPs, help us establish a highly fluorescent and long-term antibacterial system (i.e., m-SiO2/CdTe/Ag NSs). More importantly, CdTe QD-embedded m-SiO2 NSs showed fluorescence quenching when they encounter bacteria, which was avoided by attaching Ag NPs outside. Ag NPs are superior to CdTe QDs for preventing bacteria invasion because of the structure (well-dispersed Ag NPs), size (small diameter), and surface charge (positive zeta potentials) of Ag NPs. The plausible antibacterial mechanisms of m-SiO2/CdTe/Ag NSs toward both Gram-positive and Gram-negative bacteria were established. As for potential applications, m-SiO2/CdTe/Ag NSs were developed as fluorescent anticounterfeiting ink for enhanced imaging applications.

Sustainable synthesis of luminescent CdTe quantum dots coated with modified silica mesoporous nanoparticles: Towards new protein scavengers and smart drug delivery carriers

“…QD-silica nanoparticles so far described involve the coating of quantum dots with solid silica, 15,16,17,18,19,20,21 while scarce examples of QDs covered with mesoporous silica nanoparticles (MNs) have been described 22 . In those cases, most often QDs are embedded into the mesoporous, bringing down any other possibility to further encapsulate active drugs or active components.…”

Mesoporous Silica‐Based Materials with Bactericidal Properties

“…MS NPs loaded with CdTe quantum dots and coated with AgNPs were also used as antibacterial materials. [249] The pores of the mesoporous nanoparticles were loaded with mercaptopropionic acid-coated CdTe QDs and the external surface functionalized with N-(aminoethyl)-aminopropyl trimethoxysilane. Finally, Ag(I) ions were coordinated with the N-(aminoethyl)aminopropyl moieties and then transformed onto AgNPs using the silver-mirror reaction.…”

Stimuli‐Responsive Naphthalene Diimide as Invisible Ink: A Rewritable Fluorescent Platform for Anti‐Counterfeiting

“…Functional materials because of their unique optical properties offer improved security features due to the difficulty related to duplicate of their unique functions especially the colorimetric approach for authentication is of great interest as visible security features on banknotes, documents, etc. A library of materials, including lanthanides, [21][22][23][24][25][26] organic dyes, [27][28][29] conjugated polymer dots, [30] quantum dots, [31][32][33][34][35] carbon dots, [36][37][38][39] metal-organic frameworks (MOFs), [40][41][42][43][44] etc., have been explored with their respective technologies to serve the purpose. All the abovecited categories have some pros and cons [45] such as photo-stability, toxic nature, low emission property, emission at wide wavelength range, etc.…”