Arrayjet Advance™ manufacturing services worked with a prominent US-based proteomics company to improve its protein array production and enhance its yield while minimizing sample waste.
Figure 1. Team of extremely satisfied Arrayjet customers (left) after the Ultra Marathon II installation in Baltimore, USA. TheUltra Marathon II (right) is enclosed within the JetMosphere MaxTM environmental control unit to enable ultra low temperature printing. Image Credit: Arrayjet Ltd
CDI Laboratories had suffered ongoing production delays, inconsistency between batches, loss of yield and sample waste when working with the company’s low-throughput contact pin-printing system; issues which saw CDI Laboratories struggle to produce the large quantities of high-quality protein arrays required to meet demand.
The company was facing significant pressure to commercialize its product in a dependable way without exponentially increasing maintenance and other production costs.
Case study background
Arrayjet Advance™ custom printing services supported the CDI project that was launched in 2011. By leveraging the company’s end-to-end CRO microarray service, CDI Laboratories was able to access over 75 years’ combined microarray experience at Arrayjet HQ.
This allowed the effective optimization, commercialization and technology transfer of the company’s protein array.
Assay optimization
In order to commence assay optimization, a combination of Arrayjet’s Ultra Marathon II microarrayer with the JetMosphere Max™ environmental control (set to 4 °C) was used to print a targeted subset of proteins from CDI’s human protein library onto epoxysilane (Figure 2) and nitrocellulose surfaces.
A series of different test volumes were dispensed to determine the optimum deposition volume. This enabled the printing of a total of 14 identical mini arrays with a spot circularity of >99%. Assay and analysis of the mini arrays revealed the anticipated expression pattern.
Figure 2. Assay optimization on epoxysilane slides. Image Credit: Arrayjet Ltd
Batch printing
With small batch printing capabilities established, a larger subset of protein samples – again, from CDI’s human protein library – was spotted onto 200 epoxysilane and nitrocellulose slides. This was done to facilitate additional analysis of spot reproducibility, circularity and morphology (Figure 3).
Arrayjet’s Jetguard™ was employed to ensure minimal sample evaporation throughout this longer print run.
Figure 3. Subset of protein samples purified from the human protein library and printed across 200 identical Grace Bio-Labs PATH® nitrocellulose slides. Image Credit: Arrayjet Ltd
High density printing
With confirmed functional protein assays in place, it was possible to transfer from pin-spotting to Arrayjet’s inkjet technology.
The next step of the process involved an investigation into the Ultra Marathon II microarrayer’s high-density printing capabilities.
To evaluate this, samples from CDI’s human protein library were printed in a hexagonal array at high density in order to assess their inter- and intra-slide reproducibility on a range of substrates. It was also important to maintain low background throughout this process.
The resulting slides exhibited consistent spot alignment and no evidence of merging.
Printing the entire human protein library
A full set of more than 19,000 GST fusion proteins from CDI’s human protein library was purified prior to being printed in duplicate across 500 slides. This was done at a sample deposition volume of 200 pL (Figure 4).
Figure 4. Samples from CDI’s comprehensive human protein library printed on Grace Bio-Labs PATH® protein microarray slides. Image Credit: Arrayjet Ltd
The agreed success criteria were all met throughout this process. These included:
- Ensuring that >97% of spots were present on each slide
- Ensuring that spot circularity was >90%
- Ensuring that inter- and intra-slide Coefficient of Variability (CV) values were consistently <20%
These results were verified as being positive and accurate via functional analysis.
Conclusion
With technology transfer now completed and successful, CDI Laboratories is able to produce the largest human proteome microarray in the world. The company can now print their HuProt™ Version 3.1 arrays across a total of 1,000 slides in a single batch.
By acquiring and employing the Arrayjet Ultra Marathon II, CDI Laboratories can print proteome and custom microarrays suitable for the efficient analysis of thousands of protein interactions in-house while ensuring there is minimal use of valuable clinical data samples.
By leveraging the power of the Arrayjet Advance™ service and non-contact piezoelectric technology, CDI Laboratories has significantly increased its production efficiency for printing large, high-quality batches of protein microarrays.
The use of an appropriate environmental control unit ensures that excellent spot morphology and array alignment are maintained while simultaneously and precisely retaining the native conformation of proteins – a key factor in the production of consistent assays.
Dr. Ignacio Pino, CEO, CDI Laboratories explains the benefits of this work:
“CDI Laboratories purchased an Arrayjet Ultra Marathon II to print microarrays for our HuProt™ product line, and to print focused arrays with smaller subsets of proteins for discovery and hybridoma projects.
“CDI is planning to print monoclonal antibody arrays and membrane protein arrays with the new technology in the near future. We chose Arrayjet’s technology as we needed to quintuple our capacity, preferably with one instrument, and Arrayjet’s high-tech, precise and user-friendly capabilities were an obvious benefit.
“One of the added advantages of Arrayjet’s company structure is that it provides in-house printing through Arrayjet Advance. We were able to carry out several studies over several months to reaffirm our belief that the technology would improve many facets of our operation.”
Dr. Heng Zhu, Professor, Johns Hopkins School of Medicine elaborates: “Arrayjet’s Jetspyder™ sample aspiration device effectively eliminates any cross-contamination between protein samples, so the quality of our microarrays has significantly improved.
“Previously, we could only produce 150 slides of acceptable quality in a print run, which is too slow a pace for the scale and growth of current and future demand. Being able to quickly print up to 1000 slides in a highly efficient manner was incredibly appealing to us.”
About Arrayjet Ltd
Arrayjet provide instruments and services to the pharma, diagnostic and life science industries. Our products use inkjet technology for precision picolitre liquid handling. Arrayjet focus on printing samples to create tools for genomic and proteomic screening, patient stratification and clinical diagnosis.
The proprietary printing technology is fully automated and delivers benefits of ease of use, precision, reproducibility, efficiency of manufacture, and total process-control.
Arrayjet’s patented technology simultaneously aspirates and prints multiple samples on-the-fly. This is a proven platform and its non-contact bioprinting is ideal for microarray and 96 well microplate manufacture; as well as bioprinting onto biosensors, biochips, MEMS devices, microfluidic devices, membrane sheets and into nanowell applications. Most substrates are compatible with the technology.
Arrayjet instruments offer the largest manufacturing batch size of up to 1000 slides, allowing over 18,400 samples to be loaded at once. The instruments are modular and scalable, enabling customers to increase capacity as their requirements grow. They combine the fastest and most reliable instrumentation on the market with the versatility to print any biological sample type onto any solid substrate.
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