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Laser-induced forward transfer (LIFT) is a rapid laser-patterning technique for high-throughput combinatorial synthesis directly on glass slides. A lack of automation and precision limited LIFT applications to simple proof-of-concept syntheses of fewer than 100 compounds. Here, we report an automated synthesis instrument that combines laser transfer and robotics for parallel synthesis in a microarray format with up to 10000 individual reactions/cm2. An optimized pipeline for amide bond formation is the basis for preparing complex peptide microarrays with thousands of different sequences in high yield with high reproducibility. The resulting peptide arrays are of higher quality than commercial peptide arrays. More than 4800 15-residue peptides resembling the entire Ebola virus proteome on a microarray were synthesized to study the antibody response of an Ebola virus infection survivor. We identified known and unknown epitopes that serve now as a basis for Ebola diagnostic development. The versatility and precision of the synthesizer is demonstrated by in situ synthesis of fluorescent molecules via Schiff base reaction and multi-step patterning of precisely definable amounts of fluorophores. This automated laser transfer synthesis approach opens new avenues for high-throughput chemical synthesis and biological screening.

Considerable research efforts have been devoted to surface‐enhanced Raman spectroscopy (SERS), due to its excellent performance in biosensing and imaging. Here, a novel and facile strategy for the fabrication of well‐defined and uniform nanodimers as SERS substrates is presented. By the assistance of ultrasound, the violent polyol process for particle generation becomes controllable, enabling the self‐assembly of nanostars to nanodimers. Moreover, the aggregation of nanodimers can be easily tuned by post‐ultrasonic treatment, which gives a sensitive substrate for SERS., Made of nanostars: By the assistance of ultrasound, the violent polyol process for silver particle generation becomes controllable, enabling the self‐assembly of nanostars to nanodimers. Moreover, the aggregation of nanodimers can be easily tuned by post‐ultrasonic treatment, which gives a sensitive substrate for SERS.

Short-lived micro-sized thermal gradients are challenging to measure. Especially, in thin film processes and devices, it is important to know the exact temperature profile to assure process parameters and the stability of sensitive materials. Many theoretical models try to describe the occurring temperatures, but still lack in profound experimental data. Here, a facile approach is presented, which allows to measure confined temperature gradients with millisecond and micrometer precision. By casting a thin alkane film onto a substrate of interest, it is possible to reconstruct local temperature gradients by imaging the phase behavior and morphology of the alkane film with a simple optical microscope setup. Alkanes are inert and their melting and boiling temperatures depend on the chain length. This allows to measure temperatures between 37 and 522 °C on any surface. Furthermore, after thorough characterization of laser-induced temperature gradients, this approach can be used to measure the phase transition behavior of complex thin film polymer mixtures.

Single glycan–protein interactions are often weak, such that glycan binding partners commonly utilize multiple, spatially defined binding sites to enhance binding avidity and specificity. Current array technologies usually neglect defined multivalent display. Laser‐based array synthesis technology allows for flexible and rapid on‐surface synthesis of different peptides. By combining this technique with click chemistry, neo‐glycopeptides were produced directly on a functionalized glass slide in the microarray format. Density and spatial distribution of carbohydrates can be tuned, resulting in well‐defined glycan structures for multivalent display. The two lectins concanavalin A and langerin were probed with different glycans on multivalent scaffolds, revealing strong spacing‐, density‐, and ligand‐dependent binding. In addition, we could also measure the surface dissociation constant. This approach allows for a rapid generation, screening, and optimization of a multitude of multivalent scaffolds for glycan binding., Interactions of proteins with glycans rely on multivalency, where multiple adjacent binding events are involved. To study this glycan density‐dependent binding, a facile technique to synthesize peptide‐based multivalent carbohydrate scaffolds in parallel, directly on‐chip, in the microarray format, was developed. This allows to rapidly generate arrays of multivalent glycan structures, without the need for individual multistep syntheses per compound.

In this work, we present a qualitative and quantitative experimental analysis, as well as a numerical model, of a novel variant of the laser-induced forward transfer, which uses millisecond laser pulses. In this process, soft material nanolayer spots are transferred from a donor slide, which is coated with the soft material layer, to an acceptor slide via laser irradiation. This method offers a highly flexible material transfer to perform high-throughput combinatorial chemistry for the generation of biomolecule arrays. For the first time, we show visual evidence that the main transfer mechanism is contact-based, due to thermal surface expansion of the donor layer. Thus, the process is different from the many known variants of laser-induced forward transfer. We characterize the maximum axial surface expansion in relation to laser power and pulse duration. On this basis, we derive a numerical model that approximates the axial surface expansion within measurement tolerances. Finally, we analyze the topology of the transferred soft material nanolayer spots by fluorescence imaging and vertical scanning interferometry to determine width, height, and shape of the transferred material. Concluding from this experimental and numerical data, we can now predict the amount of transferred material in this process.

We developed a next-generation method for chemical in–situ combinatorial biomolecule array synthesis. This allows for an unprecedented combinatorial freedom in the automated chemical synthesis of molecule arrays with very high spot densities. Key feature of this new method is an automated positioning and laser transfer process: Small solid material spots are rapidly transferred from a donor film to an acceptor surface, requiring only minute amounts of materials. The transfer is performed with different and easy-to-produce donor slides. Each donor slide bears a thin polymer film, embedding one type of monomer. The coupling reaction occurs in a separate heating step, where the matrix becomes viscous and building blocks can diffuse within the material and couple to the acceptor surface. Since these transferred material spots are only several nanometers thin, this method allows for a consecutive multi-layer material deposition of e.g. activation reagents and amino acids. Subsequent heat-induced mixing facilitates an in–situ activation and coupling of the monomers. Positioning several of such resin spots, containing different chemical reagents, on top of each other, will enable for the first time in such small dimensions unique chemical synthesis strategies for each spot. Amount and concentration of the deposited materials can be adjusted with the laser parameters. Employing similar arrays, we can analyze the human immune response towards the proteome of different pathogens. We screened several peptide array replicas with different patient sera. The screenings resulted in significant hits in several proteins with interesting implications for future diagnostics and vaccine development.

A low-cost laser-based printing setup is presented, which allows for the spot-wise patterning of surfaces with defined polymer nanolayers. These nanolayer spots serve as a “solid solvent,” embedding different chemicals, chemical building blocks, materials, or precursors and can be stacked on top of each other. By melting the spot pattern, the polymer-embedded molecules are released for chemical reaction. This enables researchers to quickly pattern a surface with different molecules and materials, mixing them directly on the surface for high-throughput chemical synthesis to generate and screen diverse microarray libraries. In contrast to expensive ink-jet or contact printing, this approach does not require premixing of inks, which enables in situ combinatorial mixing. Easy access and versatility of this patterning approach are shown by generating microarrays of various biomolecules, such as glycans for the first time, to screen interactions of antibodies and lectins. In addition, a layer-by-layer solid-phase synthesis of peptides directly on the microarray is presented. Amino acid–containing nanolayers are repeatedly laser-transferred and reacted with the functionalized acceptor surface in defined patterns. This simple system enables a reproducible array production, down to spot-to-spot distances of 100 μm, and offers a flexible and cheap alternative to expensive spotting robot technology.