Probe design involves creating molecules that specifically bind to biological targets like proteins, nucleic acids, or metabolites. Designed for high sensitivity, selectivity, and stability, probes can be fluorescent, radioactive, or enzymatic. They enable precise visualization of cellular processes, disease markers, and drug targets, making them essential in chemical biology and molecular imaging.

Imaging agents are compounds developed to enhance the visualization of specific tissues, organs, or cellular events using imaging modalities like MRI, CT, PET, SPECT, or optical imaging. These agents include contrast-enhancing chemicals, fluorescent dyes, and radiolabeled compounds that interact uniquely with targeted areas. By increasing contrast or marking particular biological processes, imaging agents allow detailed assessment of anatomy, disease progression, and therapeutic effects in both clinical and research settings.

Click chemistry is a class of reactions known for their simplicity, high yield, and compatibility with various conditions, making them ideal for connecting molecules in biological, pharmaceutical, and material sciences. The most famous example, copper-catalyzed azide-alkyne cycloaddition (CuAAC), is used widely in bioconjugation, enabling efficient attachment of probes, drug molecules, or other functional groups to biological macromolecules. Click chemistry’s reliability and ease of use make it invaluable in applications where biocompatibility and reaction speed are critical.

Bioorthogonal chemistry encompasses chemical reactions that can occur within living organisms without interfering with native biochemical pathways. These reactions, often involving copper catalysis, enable researchers to tag and manipulate biomolecules in vivo without disrupting cellular function. By enabling selective labeling of proteins and other biomolecules, bioorthogonal chemistry has revolutionized live-cell imaging, drug delivery, and therapeutic modification.