Surface modifying agent (SMA)

Surface modifying agents (SMAs) are a diverse group of substances, including lipids, polymers, and small molecules, used to alter the physical and chemical characteristics of surfaces or interfaces [ScienceDirect]. In clinical medicine, the most significant application of SMAs is in the form of pulmonary surfactants, which are essential for reducing surface tension within the alveoli to prevent lung collapse during expiration [StatPearls, 2023]. These agents are also extensively used in pharmacology to improve the solubility and stability of drug formulations and in the engineering of medical devices to enhance biocompatibility [PubMed, 2014]. By coating surfaces, SMAs can prevent the foreign body response by inhibiting the adsorption of plasma proteins and the subsequent activation of inflammatory pathways [NIH, 2015]. Additionally, they are employed in drug delivery systems, such as PEGylated nanoparticles, to evade the mononuclear phagocyte system and extend the half-life of therapeutic agents [PubMed, 2020]. Because the term describes a functional category of materials rather than a specific biological protein or receptor, it is not considered a discrete therapeutic target.

Other names

Surface-active agentSurfactantWetting agentEmulsifierCoating agentAmphiphile

Surface modifying agents function by adsorbing to interfaces to reduce surface or interfacial tension, or by forming a protective barrier on surfaces to prevent non-specific biological interactions such as protein fouling or bacterial adhesion.