Description

Biomedical assays relying on optical nanoprobes are crucial for advancing human health. These nanomaterials possess unique optical properties and are extensively employed in various biomedical applications. In contrast to conventional materials, high-performing optical nanoprobes offer distinct advantages, including minimal interference from background fluorescence and scattering, straightforward operational procedures and instrumentation, remarkable sensitivity and outstanding specificity. Hemiluminescent and upconversion luminescent nanoprobes offer an advantage by circumventing background interferences, as they do not require shorter wavelength excitation light. Nanoprobes and luminescence quenching nanoprobes utilize a donor and an acceptor, which can be connected or disconnected by the analyte. Optical nanoprobes find utility in both in vitro diagnostics and in vivo imaging. In vitro applications encompass the identification of various biomacromolecules and small molecules, while in vivo imaging is instrumental in diagnosing inflammation and tumors.

Biological nanoparticles

Nanoparticles (NPs) have garnered significant attention in both therapeutic and diagnostic fields due to their distinctive physicochemical attributes, which have revolutionized medical treatments, offering more potent, less toxic and intelligent outcomes. This presents a comprehensive overview of the primary categories of NPs utilized for drug delivery and diagnosis. It delves into their fabrication techniques, characterization methods and inherent physicochemical properties. Additionally, it examines the clinical advancements in nanomedicine. Concluding with a discussion on the applications of NPs in in vitro diagnosis, in vivo imaging and theranostics. Nanoparticles typically serve as the core components in nanobiomaterials. However, for effective interaction with biological targets, a biological or molecular coating acting as an interface must be attached to these nanoparticles. Such coatings, aimed at rendering the nanoparticles biocompatible, encompass antibodies, biopolymers, or monolayers of small molecules. Leveraging nanoparticles and nanodevices offers several potential advantages, including an expanded capacity for label multiplexing. Various types of fluorescent nanoparticles and nanostructures have emerged as viable alternatives to conventional fluorescent organic dyes in biotechnology. Examples include Quantum Dots (QDs) as well as dye-doped polymer and silica nanoparticles.

Photothermal therapy

Chemiluminescence (CL) manifests as a form of electromagnetic radiation arising from chemical reactions. It involves the emission of photons from excited states to ground states. Typically, unstable intermediate radicals break down to produce electrically excited species, which then deactivate, leading to the phenomenon of CL. CL is broadly categorized into two types based on luminescence processes: Direct and indirect. While CL shares many characteristics with fluorescence, the key difference lies in the origin of excitation energy. Fluorescence relies on external light sources, whereas CL derives its excitation energy from self-chemical reactions. In a chemical reaction, atoms or molecules become energized by consuming chemical energy, and upon returning to their ground state, they release energy in the form of visible radiation. The absence of an external light source, a distinctive trait of CL, typically results in high sensitivity. Thus, CL's unique property of emitting radiation without external stimulation contributes to its high sensitivity. Photothermal Therapy (PTT) represents a cutting-edge approach to combat cancer, harnessing light energy to eradicate malignant cells. PTT relies on converting light into heat energy to effectively eliminate cancerous tissue. Additionally, PTT utilizes imaging techniques to precisely locate cancer cells and monitor the real-time response of PTT agents within tumors. A significant advancement in this field involves the integration of Aggregation-Induced Emission fluorogens (AIEgens) into imageguided PTT protocols for cancer treatment. AIEgens exhibit intense fluorescence when aggregated, thereby enhancing imaging accuracy while boasting low toxicity. These properties make AIEgens promising agents for both photoacoustic and photothermal imaging in PTT applications. In vivo imaging technology plays a crucial role in non-invasively observing and analyzing biological processes within living organisms. Optical imaging, particularly utilizing fluorescence and bioluminescence probes, has emerged as a superior method due to its high resolution and specificity. However, visualizing deep-seated cancer cells and administering treatment using optical technology poses challenges. To address these limitations, researchers are increasingly turning to AIEgens as a burgeoning area of research to invigorate cancer treatment strategies.