The technology proposed can be used for the fabrication of arrays of micro-needles made by biodegradable materials. The process developed possesses great flexibility in shaping sharp biodegradable microneedles with the mechanical properties needed for indentation. We set –up a non-contact and room temperature electro-drawing process for the direct and rapid fabrication of biodegradable microneedles by means of an ElectroHydroDynamic (EHD) effect. The micro-needles are formed directly onto a flexible patches, a disposable strip that is inserted into a cuff, overcoming the technological limitations of both microcasting and drawing lithography and opening new frontiers in the field of transdermal delivery. Upon stimulation, the cartridge of drug-encapsulated, biodegradable polymer microneedles, is able to deliver into hypodermic tissue both hydrophobic and hydrophilic bioactive agents, according to a predefined chrono-programme. Actually the technology proposed achieves a good control on the process and on the geometrical needles features. From an operational point of view it is possible to activate the fabrication process in the same moment over a matrix of starting polymer drops.
The device is realized by printing directly liquid and high viscous polymer in non-contact mode. The patented printing method proposed overcomes the limitations of conventional EHD ink-jet processes extending the use to multifunctional polymeric materials and 3D printing using a simple and flexible set-up.
Hypodermic needle injection is still the most common method of drug delivery despite its numerous limitations and drawbacks, such as pain, one shot administration, and risk of infection.
The proposed method overcomes all the limitations deriving from the micro-casting and the drawing lithography approach, since no hazardous temperatures, no multi-step filling process and no UV are required. In fact, biopolymers are processed directly from solution at room temperatures and are shaped directly into microneedles in a single step. This is a further advantage respect to the conventional technique where the temperature involved in the process is usually high, widening the types of drug that could be inserted in the polymeric needle. The method proposed is fast, simple, repeatable, contact-free, it avoids the use of moulds allowing the fabrication of biodegradable polymer microneedles into a ready-to-use configuration.
In general it is possible to develop on-demand and cost-effective microneedles directly in situ at the point of care, thus replacing the traditional syringes. It is possible to encapsulate hydrophobic as well as hydrophilic compounds. In addition, microneedle fabrication can be suitable for the microengineerization of polymer microneedles, a porous micro-structure can be tuned to modulate polymer degradation and thus control the profile release, making way for homemade patches and customized therapies. Moreover including the capability of high resolution printing the functionalization of materials would be very simple by dispensing very small amount of material of interest.
The technique has not been tested for drug delivery in living tissue yet.
Transdermal drug delivery
Giulio Bollino
