Needle-free delivery of fluids from compact laser-based jet injector

Jet injection devices have been studied and developed for transdermal drug delivery to avoid the use of needles. Due to bulky actuation mechanisms, they are limited to body areas that are easy to reach such as skin. Here, we demonstrate a thin and long liquid delivery system (e.g. flexible and 30 cm long with 1.2 mm outer diameter) compatible with minimally invasive surgical procedures. The actuation mechanism is based on optical cavitation in a capillary nozzle where a laser pulse is delivered via a multimode optical fibre. We show good controllability of the jet speed by varying the actuation laser fluence. The generated jets can successfully penetrate into a 1% agarose gel which is representative of the mechanical properties of several soft body tissues. We further observe that when the system is used in a low laser energy regime (<60 μJ), the ejection is in the form of the single droplet which is promising for fluid delivery with high volume precision or drop-on-demand inkjet printing. The jet injection system we propose has the potential to deliver heat-sensitive therapeutics as we show processing of biomolecules without altering their functionality.