Laser Forward Transfer: Direct-writing arrays of single microbeads

Microbead-based biosensors, lab-on-a-chip devices, optoelectronics, and engineered tissue constructs pose a difficult challenge for direct-write technologies. The fabrication of microbead arrays with single-elements requires a highly-integrated technique. We demonstrate Laser Forward Transfer (LFT) as an ideal technique to target single microbeads with widely disparate properties, for real-time transfer into user-directed array positions. LFT enables us to generate MxM and MxN polystyrene and alginate microbead arrays. Soft transfer of microbeads were achieved with little to no thermal or UV damage to the structural and functional surfaces as a result of nanosecond-pulsed excimer laser exposure, as assessed by FTIR spectra and SEM characterization. Long-term array integrity was preserved, even under intense ultrasonication. The unique features of LFT introduce a new avenue for the fabrication of specific-microbead arrays, with customizable patterns and potential for long-term studies.