Bioimaging is one of the most important tools for diagnosing various diseases. Nanomaterials show great potential in bioimaging due to their physical and chemical properties and good biocompatibility. Alfa Chemistry extensively explores optically active nanomaterials for biological imaging, including organic nanomaterials and organic nanomaterials. We can provide you with corresponding products according to your experimental procedures to meet your needs.
Inorganic Nanomaterials
Inorganic nanomaterials, including gold nanoparticles, carbon-based nanomaterials, porous silicon nanoparticles, quantum dots, carbon nanotubes, fullerenes, and graphene, have become one of the most active research fields in biotechnology, biochemistry, and nanomedicine.
Gold Nanoparticles (GNP)
Due to its unique characteristic-surface plasmon resonance (SPR), GNP is usually chosen to enhance optical imaging based on its absorption, fluorescence, and Raman scattering. GNP is usually synthesized by HAuCl4 reduction and is stabilized by a variety of ligands that affect its size and properties. The diameter ranges from 1 nm to over 120 nm. We can also prepare a variety of shapes, such as core-shell nanostructures, nanorods, or nanocages.
Carbon-based Nanomaterials (CBN)
CBN includes fullerenes, carbon nanotubes (CNT), graphene (G), graphene oxide (GO), nanodiamonds (NDD), and carbon dots (CD). The surface can be modified with functional groups such as carboxylic acid, hydroxyl, or epoxy to optimize performance. The extraordinary optical properties of CBNs increase their potential for cell or tissue imaging and diagnosis, such as inherent fluorescence, high photostability, and tunable narrow emission spectra. After functionalization, their biocompatibility is better than carbon nanotubes and carbon black.
Figure.1 (A) Schematic representation of the synthesis of QD-rGO. (B) Fluorescence of the QD-tagged 38 nm rGO and the QD-tagged 260 nm rGO. (C) Cellular uptake of FA-QD-US-rGO. (D) Schematic illustration of QD-rGO under irradiation that causes cell death and diminished QD fluorescence (a) and images before (b) and after (c) irradiation. (Zhang Y. Y, et al. 2018)
Porous Silicon Nanoparticles (pSiNPs)
The optical properties of silicon nanostructures, known as intrinsic photoluminescence, provide an alternative to biological imaging. Compared with semiconductor quantum dots, pSiNPs have better biocompatibility, biodegradability, and lower toxicity.
Lanthanide-doped Upconversion Nanoparticles (Ln-UCNPs)
Ln-UCNPs can convert two or more low-energy near-infrared (NIR) photons into high-energy emission through a nonlinear anti-Stokes process. Due to its special up-conversion luminescence characteristics and stable Ln-based inorganic framework, Ln-UCNPs have been developed as promising alternatives to organic dyes and quantum dots. It has several advantages, such as high resistance to photobleaching and light scintillation, negligible background autofluorescence, deeper tissue penetration, etc. Many functional components with other imaging capabilities are introduced into these nanoparticles for diagnostic and therapeutic applications.
Quantum Dots (QD)
QDs of various sizes or components are excited by a single light source and emit different colors in a wide range, making it an ideal choice for multiple imaging. By adjusting the size, configuration, and components of the QD, the QD can be adjusted to emit over a wide wavelength range. The main quantum dots involved in biomedicine include Cd-based quantum dots (CdSe, CdTe, CdS) or cadmium-free quantum dots (InP, CuInS2, AgInS2, Ag2S, WS2, ZnO, silicon, GQDs, CuS).
Organic Nanomaterials
Inorganic nanoparticles usually have serious safety issues, including heavy metal poisoning, and not easy to quickly remove from the body. In order to promote clinical transformation, organic systems are usually preferred.
Fluorescent agents with aggregation-induced emission (AIEgens) are typical organic nanomaterials, which exhibit very weak emission in the molecular state, but exhibit strong fluorescence in the aggregate state. Some biomolecules can be integrated into AIEgens without affecting its AIE properties, such as targets or chelating agents. AIEgens has successfully combined with PS, drugs, and multiple imaging methods to achieve an efficient diagnosis and treatment platform.
Figure.2 AIEgens for Functional Imaging of Mitochondria. Photoactivatable o-TPE-ON+ for super-resolution nanoscopic imaging of mitochondria. (Qian J, et al. 2017)
Due to the poor light stability of traditional near-infrared organic dyes, organic semiconductor reagents, including semiconducting polymer nanoparticles (SPNs) and semiconducting molecular nanoparticles (SMNs), have become excellent candidates. Compared with inorganic reagents, these reagents have a higher absorption coefficient, more adjustable optical properties, and controllable size. Nowadays, organic semiconductor reagents have been used for deep tissue imaging, including NIR-II fluorescence, self-luminescence, and PA imaging, in the field of biomedicine such as cell, tumor, acute edema, and cardiovascular imaging.
Polymer nanoparticles (PNPs) have been widely used in biological imaging due to their high extinction coefficient, extraordinary fluorescence intensity, good photostability, biocompatibility, and simple packaging of imaging probes.
Applications
The photoactive nanomaterials we provide can be widely used in the following bioimaging fields:
- Fluorescence Imaging
- Persistent Luminescence Imaging
- Photoacoustic (PA) Imaging
- Near-Infrared Surface-Enhanced Raman Scattering (NIR SERS) Imaging
References
- Zhang Y. Y, et al. (2018). “Multifunctional Carbon-Based Nanomaterials: Applications in Biomolecular Imaging and Therapy.” ACS Omega. 3(8): 9126-9145.
- Qian J, et al. (2017). “AIE Luminogens for Bioimaging and Theranostics: From Organelles to Animals.” Chem. 3(1): 56-91.
