Tough,Resorbable Polycaprolactone-Based Bimodal Networks for Vat Polymerization 3D Printing

Vat polymerization allows for the accurate and fast fabrication of personalized implants and devices. While the technology advances rapidly and more materials become available, the fabrication of flexible yet tough resorbable materials for biomedical applications remains a challenge. Here, a formulation that can be 3D printed with high accuracy using vat polymerization, yielding materials that are tough, degradable, and non-toxic is presented. This unique combination of properties is obtained by combining a long-chain polycaprolactone macromonomer with a small molecule cross-linker. A wide range of properties is achieved by tuning the ratio of these components. The use of benzyl alcohol as a non-volatile, benign solvent enables fabrication on a low-cost desktop 3D printer, with an exposure time of 8 s per 50-micron layer. The 3D-printed networks are tough and elastic with a tensile strength of 11 MPa at 116% elongation at break. Cells attach and proliferate on the networks with a viability of >91%. The networks are fully degradable to soluble products. This new 3D printable material opens up a range of opportunities in biomedical engineering and personalized medicine.     

Pen Plotter as a Low-Cost Platform for Rapid Device Prototyping with Solution-Processable Nanomaterials

The use of inexpensive benchtop plotters in combination with refillable writing pens and markers as a powerful route to print nanomaterial-based inks on paper substrates is studied. It is proved that this approach is very robust, it can be used to print inks of many different solution-processable nanomaterials, and is very precise, allowing pattern features with pitch separation as narrow as 80 μm. The general character of this printing platform by printing van der Waals materials, organic semiconductors, hybrid perovskites and colloidal nanoparticles with a broad range of properties (from insulators to superconductors) is illustrated. The system is used to easily create several example applications such as an all-printed, paper-supported photodetector. This printing platform can be very helpful for research groups with a wealth of expertise in synthesis of solution-processable nanomaterials but that lack the infrastructure, resources, and expertise to perform traditional inkjet printing for fast device prototyping.