title: Exploiting oxidative microenvironments in the body as triggers for drug delivery systems.
abstract: CONCLUSIONS
  Reactive oxygen species and reactive nitrogen species (ROS/RNS) play an important role in cell signaling pathways. However, the increased production of these species may disrupt cellular homeostasis, giving rise to pathological conditions. Biomaterials that are responsive to ROS/RNS can be strategically used to specifically release therapeutics and diagnostic agents to regions undergoing oxidative stress.
  
  
  BACKGROUND
  Many nanocarriers intended to exploit redox micro-environments as triggers for drug release, summarized and compared in this review, have recently been developed. We describe these carriers' chemical structures, strategies for payload protection and oxidation-selective release, and ROS/RNS sensitivity as tested in initial studies.
  
  
  RESULTS
  ROS/RNS are unstable, so reliable measures of their concentrations in various conditions are scarce. Combined with the dearth of materials shown to respond to physiologically relevant levels of ROS/RNS, evaluations of their true sensitivity are difficult.
  
  
  CONCLUSIONS
  Oxidation-responsive nanocarriers developed thus far show tremendous potential for applicability in vivo; however, the sensitivity of these chemistries needs to be fine tuned to enable responses to physiological levels of ROS and RNS.
authors: 1 Skaggs School of Pharmacy and Pharmaceutical Sciences, Laboratory of Bioresponsive Materials, University of California , San Diego, San Diego, California.
authors: Shivanjali
authors: S
authors: Joshi-Barr
authors: Caroline
authors: C
authors: de Gracia Lux
authors: Enas
authors: E
authors: Mahmoud
authors: Adah
authors: A
authors: Almutairi
mesh_terms: D000818:Animals; D004337:Drug Carriers / Q000737:chemistry / Q000378:metabolism; D016503:Drug Delivery Systems / Q000379:methods*; D006801:Humans; D049329:Nanostructures / Q000737:chemistry*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D026361:Reactive Nitrogen Species / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D004337:Drug Carriers; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species