Silicon Quantum Dot Supraparticles for Fluorescence Bioimaging

Abstract

We developed a self-limited self-assembly process to produce red-to-near-infrared luminescent supraparticles made from biocompatible silicon (Si) quantum dots (QDs) for fluorescence bioimaging. A starting material is a methanol solution of boron (B) and phosphorus (P) codoped all-inorganic Si QDs. The Si QDs have a heavily B and P codoped amorphous shell, and the shell induces negative potential on the surface, which prevents agglomeration of QDs in polar solvents. By adding toluene to the methanol solution, controlled agglomeration of Si QDs occurs and spherical supraparticles around 100 nm in diameter with a narrow size distribution are grown. The average diameter of supraparticles was controlled by the growth parameters. We also developed a process to stabilize the supraparticles by coating the surface by polyvinylpyrrolidone (PVP) and then by silica. The photoluminescence spectra of PVP-and silica-coated Si QD supraparticles were very similar to those of Si QDs dispersed in solution.

Self-limiting self-assembly of supraparticles for potential biological applications

“…95 Colloidal SPs can also be constructed with stable, broad, and tunable emissions for promising biological applications by collecting QDs together, such as the Cd(Se, ZnS) core/(Cd, Zn)S shell nanocrystals that emit three kinds of colors including red, green, and blue. 52 Magnetic properties, which play important roles in biological systems for bioimaging and therapy of controllable diseases, are another significant factor of SPs. Due to their collective effects and spatial confinement, the magnetization of SPs is usually stronger than that of individual building blocks (Fig.…”

“…Based on the self-limiting self-assembly approach, a kind of SP with red-to-near-infrared luminescence signals were constructed based on biocompatible silicon quantum dots for fluorescence bioimaging. 52 Au@CdS hybrid core-shell SPs were successfully used for quantitative detection of dopamine in real time if modified on the electrode. Based on the advantages of stability, sensitivity, and selectivity, Au@CdS SPs have exhibited considerable advantages in the field of medical diagnosis.…”

“…1), [46][47][48][49][50][51] such as spherical NPs (Fig. 1A-1C, 1N), 17,52,53 virus-liked nanoshells (Fig. 1D-1I), 54 and extended architectures including layer-by-layer films, 55 superlattices, [56][57][58] sheets (Fig.…”

“…Artificial nanoassemblies can bridge the gap between natural and artificial structures, and impart collective and novel properties that do not exist in nature, 3,65 for instance plasmonic, excitonic states, and magnetic properties. 24,66,67 These specific properties could also benefit the development of other fields, such as optoelectronics, 68 construction technology, biomedical applications, 23,52,53,55,61,69,70 environmental protection, 36,71,72 and food safety. 43 Reviewing the research on SPs and understanding the relationship between artificial materials and natural biological molecules are necessary to further identify the assembly mechanism, construct unique nanostructures with specific functions, and explore their potential for biological applications.…”

Erbium‐Hyperdoped Silicon Quantum Dots: A Platform of Ratiometric Near‐Infrared Fluorescence

“…[24][25][26] Hence, absorptionemission overlap and the resulting reabsorption do not occur to Si QDs. [27] Up to now, Si QDs have been extensively studied for bioimaging [28] and ions sensing. [29] Owing to the biocompatible and biodegradable properties of Si QDs they have potential to take the place of Cd-or Pb-based QDs, especially in biomedical fields.…”