Near infrared-induced heating of confined water in polymeric particles for efficient payload release

 

Mathieu L. Viger , Wangzhong Sheng , Kim Dore , Ali H. Alhasan , Carl-Johan Carling , Jacques Lux , Caroline de Gracia Lux , Madeleine Grossman , Robert Malinow , and Adah Almutairi. Near infrared-induced heating of confined water in polymeric particles for efficient payload release. ACS Nano 2014; online ahead of print March 31.

 

 

Near-infrared (NIR) light-triggered release from polymeric capsules could make a major impact on biological research by enabling spatio-temporal and remote control over the release of encapsulated cargo. The few existing mechanisms for NIR-triggered release have not been widely applied because they require custom synthesis of designer polymers, high-powered lasers to drive inefficient two-photon processes, and/or co-encapsulation of bulky inorganic particles. In search of a simpler mechanism, we found that exposure to laser light resonant with the vibrational absorption of water (980 nm) in the NIR region can induce release of payloads encapsulated in particles made from inherently non-photo-responsive polymers. We hypothesize that confined water pockets present in hydrated polymer particles absorb electromagnetic energy and transfer it to the polymer matrix, inducing a thermal phase change. In this study, we show that this simple and highly universal strategy enables instantaneous and controlled release of payloads in aqueous environments as well as in living cells using both pulsed and continuous wavelength lasers without significant heating of the surrounding aqueous solution.