Bioprinting is a rapidly expanding additive manufacturing process, for the development of complex biostructures such as tissue-like structures, able to imitate native tissue functions. Among the most commonly used bioprinting techniques, Laser Induced Forward Transfer (LIFT) offers the highest degree of spatial resolution (minimum feature of <10 μm) and post-printing cell viability while it has also been used for the immobilization of biomaterials on a variety of substrates. Furthermore, this study will present the control of the depth of cell deposition within the ECM by tuning the laser printing parameters and the organoid formation of the laser printed cells, already from Day 1 after bioprinting. Finally, the application of LIFT technique in Organ on Chip applications will be presented.
In the current work we will present the transfer of graphene pixels and arrays. The process we used to accomplish the transfer was the Laser Induced Transfer technique. We will exhibit the advantages of the certain technique, the resolution of the transferred pixels and the characterization of the samples. Also, we will demonstrate the transfer of graphene arrays on both flexible polymeric and rigid substrates. The transfer of the graphene pixels was accomplished for resolution from 40 μm to 15 μm, whereas the digital manipulation of the transfer enables the deposition of arrays with dimension up to 1 mm2. Furthermore, in this work we will present the fabrication of a flexible capacitance touch sensor. The device is composed by LIFT transfer bottom electrodes and top electrodes and between them we deposit a insulating layer with the assistance of a spin-coater. For bottom electrodes we used silver nanoparticles ink, which was LIFT transferred and laser sintered in order to be conductive and form two pads with a line to connect them. The top electrode is a transferred graphene array with dimension at 1 mm2 and the insulating layer we used is an in-house fabricated PDMS, which was deposited on the half of the bottom electrodes. The quality and quantity of graphene layers were measured and characterized with Scanning Electron Microscopy and micro-Raman spectroscopy. Electrical measurements were conducted on the same samples in order to receive the sheet resistance and the capacitance values. The capacitance measurements were conducted at the top electrode of the flexible touch sensor. Finally, we will introduce the next step in the demonstration of the touch sensor, which is the application of tensile or compressive stress on the flexible touch sensor, which will result in accumulation of different capacitance.
Aiming to harness the unique capabilities of laser printing, in this study, we present our latest results on the transfer and photo-crosslinking of cell-laden bioinks comprising different hydrogels, using a dual laser beam configuration. Results from different laser sources with ns and sub-ns pulse duration and different repetition rates are also presented to highlight the effect of the laser parameters on the printing and photo-crosslinking of the cell-laden patterns. The printing outcome is correlated with the cell growth of different cell-laden bioinks, while immunochemical staining is also employed to study potential cellular damage.
Ιn the current work we will present the transfer hBN, MoS2 and Bi2Se3-xSx by using the Laser Induced Transfer technique on rigid and flexible substrates. We will exhibit the advantages of the certain technique, the resolution of the transferred pixels and the characterization methods such as Scanning Electron Microscopy, Raman spectroscopy and Atomic Force Microscopy. Furthermore, we will refer to the possible applications concerning the Bi2Se3-xSx and the hBN. Finally, we will support the experimental results with the corresponding theoretical results of ab initio Molecular Dynamics (AIMD) with main purpose to explain the detachment and the attachment of the 2D materials from the donor to the receiver substrate.
KEYWORDS: Graphene, Modeling, Chemical vapor deposition, Scanning electron microscopy, Receivers, Raman spectroscopy, Atomic force microscopy, Copper, Nickel, Chemical species
Laser Induced Forward Transfer (LIFT) is a direct write technique, able to create micropatterns of biomaterials on sensing devices. In this conference we will present a new approach using LIFT for the printing and direct immobilization of biomaterials on a great variety of surfaces, for bio-sensor applications. The basic requirement for the fabrication of a biosensor is to stabilize a biomaterial that brings the physicochemical changes in close proximity to a transducer. In this direction, several immobilization methods such as covalent binding and crosslinking have been implemented. The presence of the additional functionalization steps in the biosensors fabrication, is among the main disadvantages of chemical immobilization methods. Our approach employs the LIFT technique for the direct immobilization of biomaterials, either by physical adsorption or by covalent bonding of the biomaterials. The physical adsorption of the biomaterials, occurs on hydrophobic or super-hydrophobic surfaces, due to the transition of the wetting properties of the surfaces upon the impact of the biomaterials with high velocity. The unique characteristic of LIFT technique to create high speed liquid jets, leads to the penetration of the biomaterial in the micro/nano roughness of the surface, resulting in their direct immobilization, without the need of any chemical functionalization layers. Moreover, we will also present the direct immobilization of biomaterials on Screen Printed Electrodes, for enzymatic biosensors, with a limit of detection (LOD) for catechol at 150 nM, and protein biosensors, used for the detection of herbicides, with an LOD of 8-10 nM.
During the last decade there is an ever-increasing interest for the study of laser processes dynamics and specifically of the Laser Induced Forward Transfer (LIFT) technique, since the evolution of the phenomena under investigation may provide real time metrology in terms of jet velocity, adjacent jet interaction and impact pressure.
The study of such effects leads to a more thorough understanding of the deposition process, hence to an improved printing outcome and in these frames, this work presents a study on the dynamics of LIFT for conductive nanoparticles inks using high-speed imaging approaches. Moreover, in this study, we investigated the printing regimes and the printing quality during the transfer of copper (Cu) nanoink, which is a metallic nanoink usually employed in interconnect formation as well as the printing of silver nanowires, which provide transparency and may be used in applications where transparent electrodes are needed as in photovoltaics, batteries, etc. Furthermore, we demonstrate the fabrication of an all laser printed resistive chemical sensor device that combines Ag nanoparticles ink and graphene oxide, for the detection of humidity fabricated on a flexible polyimide substrate. The sensor device architecture was able to host multiple pairs of electrodes, where Ag nanoink or nanopaste were laser printed, to form the electrodes as well as the electrical interconnections between the operating device and the printed circuit board. Performance evaluation was conducted upon flow of different concentrations of humidity vapors to the sensor, and good response (500 ppm limit of detection) with reproducible operation was observed.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.