Biological tissues

Biological tissues are organized groups of cells and their surrounding extracellular matrix that work together to perform specific physiological functions (National Cancer Institute, NIH). In multicellular organisms, tissues are categorized into four primary types: epithelial, connective, muscle, and nervous tissue (StatPearls, 2023). Each tissue type possesses unique structural and functional characteristics that contribute to the overall homeostasis of the organism. While drugs are designed to reach and act within specific tissues, the term 'biological tissues' refers to a level of biological organization rather than a specific molecular target like a receptor or enzyme. Consequently, it is not a valid therapeutic target in the context of pharmacology or drug discovery. Instead, tissues provide the anatomical context for target expression and drug distribution, influencing the pharmacokinetic and pharmacodynamic profiles of therapeutic agents. Understanding tissue-specific environments is essential for developing targeted delivery systems, such as antibody-drug conjugates or nanoparticles. However, for the purposes of molecular target identification, 'biological tissues' is considered an overly broad and non-specific classification.

Other names

TissueBiological tissueAnatomical tissue

Not applicable. Biological tissues are levels of biological organization consisting of cells and extracellular matrix, rather than discrete molecular targets for drug binding (National Cancer Institute, NIH).