The Rapid Deployment of a 3D Printed “Latticed” Nasopharyngeal Swab for COVID-19 Testing Made Using Digital Light Synthesis

Abstract

The novel coronavirus disease (COVID-19) has caused a pandemic that has disrupted supply chains globally. This black swan event is challenging industries from all sectors of the economy including those industries directly needed to produce items that safeguard us from the disease itself, especially personal protection equipment (N95 masks, face shields) and much needed consumables associated with testing and vaccine delivery (swabs, vials and viral transfer medium). Digital manufacturing, especially 3D printing, has been promulgated as an important approach for the rapid development of new products as well as a replacement manufacturing technique for many traditional manufacturing methods, including injection molding, when supply chains are disrupted. Herein we report the use of Digital Light Synthesis (DLS) for the design and large-scale deployment of nasopharyngeal (NP) swabs for testing of coronavirus SARS-CoV-2 infections in humans. NP swabs have been one of society's essential products hardest hit by the supply chain disruptions caused by COVID-19. A latticed tip NP swab was designed and fabricated by DLS from a liquid resin previously developed and approved for use to make dental night guard devices. These latticed NP swabs demonstrated non-inferiority in a human clinical study of patients suspected of being infected with SARS-CoV-2.

Practical strategies for SARS-CoV-2 RT-PCR testing in resource-constrained settings

“…In our limited testing, the prototype 3D-printed NMT lattice swabs showed high categorical concordance with NP swabs and also yielded similar viral loads compared to flocked NMT swabs. Similar high concordance has been demonstrated for 3D-printed nasopharyngeal swabs (18–20). Anecdotally, the prototype 3D-printed were observed to be more uncomfortable for study participants compared to flocked NMT swabs, a sentiment shared by other studies (18).…”

Performance of three-dimensional printed nasopharyngeal swabs for COVID-19 testing

“…While the materials of the 3D printed swabs are not absorbent compared to nylon bristles, 3D printing enables rapid prototyping for limitless design iterations to optimize swab parameters such as uptake efficiency. One such group 11 demonstrated how their latticed swab head bulb geometries could be optimized for sample collection as well as patient comfort and after iterations resulted in a 3D printed swabs that was comparable or better that Copan swabs. Not only can 3D printed swabs head designs be varied but their dimensions can also be modified to create more patient-specific swabs such as 3D printed swabs for children younger than 3 years of age.…”

Prospective clinical validation of 3D printed nasopharyngeal swabs for diagnosis of COVID-19

“…Compared to other published data directly evaluating 3D printed NP swab performance against the traditional flocked NP swab ( Callahan et al, 2020 , Bennett et al, 2020 ), this study offers data on a large sample of COVID-positive patients. In this study the sensitivities of the swabs are robust with a relatively narrow 95% CI.…”

“…In the span of days-to-weeks, numerous 3D printing companies went through an iterative design process ( Callahan et al, 2020 , Bennett et al, 2020 ) to meet the requirements of the NP swab: 1) to collect an adequate patient specimen from the nasopharyngeal mucosa, and 2) to elute the sample into a reverse transcription polymerase chain reaction (RT-PCR) assay without affecting the quality of results. Quality design controls and early clinical use have demonstrated similar safety profiles to NP swabs currently on the market ( Gupta et al, 2020 ).…”