nearphysiological

Near-physiological conditions refer to experimental settings designed to resemble, but not exactly reproduce, the physiology of living tissues and organisms. The term is used across biology and biomedical engineering to describe a deliberate departure from idealized, simplified laboratory conditions in favor of greater biological relevance while maintaining experimental control.

In cell culture and tissue engineering, near-physiological conditions often involve adjusting temperature, pH, osmolarity, and gas composition to approximate those found in the body. Common targets include about 37°C, pH around 7.35–7.45, osmolarity near 290–310 mOsm/kg, and a reduced oxygen tension to reflect tissue levels rather than room air.

Systems achieving near-physiological states may incorporate dynamic perfusion, mechanical stimulation, three-dimensional extracellular matrices, and culture media that more closely resemble plasma or interstitial fluid composition. Such approaches seek to improve functional readouts, cellular interactions, and translational relevance, particularly in pharmacology and organ-on-a-chip research.

However, near-physiological conditions remain a simplification, and exact replication of in vivo physiology is still unattainable in most in vitro models. Observed responses can vary across tissue types, species, and individual samples, and the term signals proximity to, rather than a guarantee of, true physiological behavior.