pH-Responsive Nanoparticles Targeted to Lungs for Improved Therapy of Acute Lung Inflammation/Injury.

Dysregulated vascular inflammation is the underlying cause of acute lung inflammation/injury (ALI). Bacterial infections and trauma cause ALI that may rapidly lead to acute respiratory distress syndrome (ARDS). There are no pharmacological therapies available to patients with ALI/ARDS, partially as drugs cannot specifically target the lungs. Herein, we developed a stimuli-responsive nanoparticle (NP) to target inflammatory lungs for ALI therapies. The NP is composed of a sharp acid-sensitive segment poly(β-amino esters) as a core for drug loading and controlled release and a polyethylene glycol-biotin on the particle surface available for bioconjugation, enabling lung targeting and extended circulation. The studies on dissipative particle dynamics simulation and characteristics of NPs suggest that anti-ICAM-1 antibodies can be coated to the particle surface and this coating is required to enhance lung targeting of NPs. A model drug of anti-inflammatory agent TPCA-1 is encapsulated in NPs with a high drug-loading content at 24% (w/w). In the mouse ALI model, our TPCA-1-loaded NPs coated with anti-ICAM-1 can target inflamed lungs after intravenous injection, followed by drug release triggered by the acid environment, thus mitigating lung inflammation and injury. Our studies reveal the rational design of nanotherapeutics for improved therapy of ALI, which may be applied to treating a wide range of vascular inflammation.