Poly(N-Isopropylacrylamide)-Functional Silicon Nanocrystals for Thermosensitive Fluorescence Cellar Imaging

Plasmon-enhanced fluorescence for ellagic acid detection based on surface structure of gold nanoparticles

Ellagic acid (EA), as a natural polyphenolic acid, is considered a naturally occurring inhibitor of carcinogenesis. Herein, we developed a plasmon-enhanced fluorescence (PEF) probe for EA detection based on silica-coated gold nanoparticles (Au NPs). A silica shell was designed to control the distance between silica quantum dots (Si QDs) and Au NPs. The experimental results indicated that an 8.8-fold fluorescence enhancement was obtained compared with the original Si QDs. Three-dimensional finite-difference time-domain (3D-FDTD) simulations further demonstrated that the local electric field enhancement around Au NPs led to the fluorescence enhancement. In addition, the fluorescent sensor was applied for the sensitive detection of EA with a detection limit of 0.14 μM. It can be used to detect EA in pomegranate rind with a recovery rate of 100.26-107.93%. It can also be applied to the analysis of other substances by changing the identification substances. These experimental results indicated that the probe provides a good option for clinical analysis and food safety.

Ratiometric fluorescence probe integrated with smartphone for visually detecting lipopolysaccharide

A portable instrument-free detection method for lipopolysaccharide (LPS) analysis was developed based on dual-emission ratiometric fluorescence sensing system. Herein, red-emitting Au nanoclusters (Au NCs) were as reference probe, while blue-emitting fluorescent silica quantum dots (Si QDs) were as response probe. Additionally, the aptamer of LPS was covalently grafted to the surface of Si QDs in order to specific recognize the LPS. According to the changes of fluorescence intensityratio (FL ratio, I_{461 nm}/I_{643 nm}) with the concentrations of LPS, the linear equation was fitted with the range of 50-3000 ng/mL, and the limit of detection (LOD) was 29.3 ng/mL. As a practical application, this method was employed to analyze LPS in normal saline with the recovery rate of 97.7-103.8 %. The color picker platform in the smartphone was used to transform the detection picture to the process of Red, Green and Blue (RGB) for visual detection of LPS. The low-cost and easy-carry method reported here presents broad merits for the visually quantitative detection of LPS.

Nanoarchitectonics horizons: materials for life sciences

Nanoarchitectonics relies on the fabrication of materials at the atomic/molecular level to achieve the desired shape and function. Significant advances have been made in understanding the characteristics and spatial assemblies that contribute to material performance. Biomaterials undergo several changes when presented with various environmental cues. The ability to overcome such challenges, maintaining the integrity and effective functioning of native properties, can be regarded as a characteristic of a successful biomaterial. Control over the shape and efficacy of target materials can be tailored via various processes, like self-assembly, supramolecular chemistry, atomic/molecular manipulation, etc. Interplay between the physicochemical properties of materials and biomolecule recognition sites defines the structural rigidity in hierarchical structures. Materials including polymers, metal nanoparticles, nucleic acid systems, metal-organic frameworks, and carbon-based nanostructures can be viewed as promising prospects for developing biocompatible systems. This review discusses recent advances relating to such biomaterials for life science applications, where nanoarchitectonics plays a decisive role either directly or indirectly.