|Hemocytometer adapter fabricated via additive manufacturing.|
Medtech giant BD (Triangle Park, NC), one of the self-described largest users of plastic injection molded products in the world, has long recognized the potential of additive manufacturing for its applications. Until now, however, it has not used the technology to make a production part. A case study published recently by Carbon (Redwood City, CA) details the use of its Digital Light Synthesis technology to fabricate a hemocytometer adapter for BD's Rhapsody single-cell genomic analysis system. The paper recounts how the partnership allowed BD to optimize part design, reduce print time by 55%, use less material and accelerate the product development cycle without sacrificing part quality.
BD’s Advanced Prototyping, Corporate Computer-Aided Engineering (CAE) team led by Larry Monahan tasked Carbon with the goal of accelerating product development throughout various business units. The engineering groups within each BD business unit then used the parts to rapidly iterate new designs and test the function of the printed parts.
Building a single-cell genomic analysis system
In mid-2017, the Corporate CAE team began providing parts to the BD Life Sciences – Genomics group based in Menlo Park, CA. The BD Genomics team was building a single-cell genomic analysis system that makes it possible to understand cellular form and function on the basis of individual cells.
Traditional assays such as microarrays and bulk RNA sequencing, which take an average of measurements across multiple cells, hide subtle differences between individual cells. The BD Rhapsody system overcomes this limitation and makes it possible to identify and characterize rare cell types, allowing researchers to understand biological processes in fields ranging from immunology to oncology, noted the white paper.
A critical component of this product is the hemocytometer adapter, which integrates a fluidic micro-well component into an optical system. The fabricated holder must accommodate the dimensions and operational requirements of both a fluidic “slide” and existing imaging technology.
The sliding surfaces and central fluidics holder required flush surfaces to fit with the other components in the assembly. Other key features included trapped negative space for the slide holder, undercut structures, and a window for optics. Injection molding and milling processes were problematic for this project because of the difficult-to-mold geometries, long lead times required to produce a mold and new tooling expenses, among other difficulties. Additive manufacturing revealed itself as a potential solution, but it had to deliver cost and speed benefits without compromising on the part’s design requirements, noted BD.