COVID-19 Tests | Wish List

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Joined: Fri Jun 26, 2020 5:22 am

Re: COVID-19 Tests | Wish List

Post by trader32176 »

Could 3D printed swabs be used to collect COVID-19 test samples?

6/2/21 ... mples.aspx

Researchers have evaluated 3D printed sample collection swabs made in-house and found them to be a reliable alternative to commercial swabs.

The detection of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is done by collecting samples from the nose and throat. The samples are usually collected using a swab, which has fibers that help better the collection and transport of the sample. As the pandemic continues throughout the world, there is a shortage of testing reagents and sampling swabs, leading to delayed results, affecting the spread of the virus.

To overcome the supply challenge, 3D printing technology was used to rapidly build prototypes. Several teams made available open-source designs for making 3D printed swabs, and workflows were established for local printing.

Researchers from the Université de Montréal and the Université du Québec in Canada evaluated the fabrication process and clinically tested 3D printed swabs manufactured within a hospital, comparing them with commercially available swabs. They reported their results in a paper published on the medRxiv* preprint server.

Evaluating swabs

The swabs were 3D printed locally at the hospital system using the designs provided by the University of South Florida and the Northwell Health system, sterilized and immediately packed individually. The team tested the swabs at their institution’s COVID-19 screening clinic.

From the two designs available, the team selected one that had a smaller head size and greater flexibility for clinical tests. To this design, they added a breaking point some distance from the tip to enable storage and transport of the swab head with the sample.

They ensured that the swab heads were sterile by inoculating the swabs with a bacteria, subjecting them to the sterilization procedure, and testing them for bacterial growth. If the sterilization procedure was effective, no bacteria would grow on the inoculated swabs.

The team tested the swabs on 63 patients, about half of who tested negative for COVID-19. They used 3D printed swabs from three different lots for collecting samples. They found no significant statistical difference in the cycle threshold counts between the PCR results obtained using the 3D printed swabs or the commercial swabs. The overall agreement between the data obtained from the two different swabs was about 97%. The data for the two samples did not agree with each other.

Potential replacement for commercial swabs

The results indicate that if there is a shortage of commercial swabs, 3D printed swabs may be used to collect samples. This finding corresponds to results from previous studies comparing 3D printed swabs with commercial swabs.

The authors were able to take advantage of their health-related 3D printing center in their institution along with sterilization services, which allowed them to quickly perform steam sterilization. Because of the available setup and presence of staff, the cost per 3D printed swab was about 56 US cents. Further optimization can lead to increased production volume and lower production costs.

Our clinical trial has demonstrated that our local 3D printed swab production line offers a reliable local alternative to commercial swabs and therefore confirms that it is a viable local response to provide replacements in the event of pandemic supply chain disruption,” write the authors.

With SARS-CoV-2 continuing to spread in many parts of the world, there will be a need for increased testing capacity. Such local methods for making sample collection swabs may help with increased testing.

*Important Notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Journal reference:

Lapierre, S. G. et al. (2021) Clinical Evaluation of In House Produced 3D Printed Nasopharyngeal Swabs for COVID-19 Testing. medRxiv., ... 21257548v1.
Posts: 2723
Joined: Fri Jun 26, 2020 5:22 am

Re: COVID-19 Tests | Wish List

Post by trader32176 »

Scientists develop low-cost lab-on-paper device for rapid and accurate detection of SARS-CoV-2

6/18/21 ... CoV-2.aspx

A team of scientists from the University of Connecticut, USA, has developed a low-cost lab-on-paper technology to rapidly and easily detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The work has recently been published in a Royal Society of Chemistry’s Lab on a Chip journal.


Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative pathogen of the coronavirus disease 2019 (COVID-19) pandemic, is an enveloped RNA virus of the human beta-coronavirus family. Being a respiratory virus, SARS-CoV-2 primarily attacks the upper respiratory tract and gradually propagates to the lower respiratory tract to cause mild to severe infection.

Reverse transcription-polymerase chain reaction (RT-PCR)-based amplification of viral RNA in respiratory samples is considered as the golden standard method to diagnose COVID-19. However, despite high accuracy, RT-PCR is not always convenient for mass detection of SARS-CoV-2 infection at the community level because of its high turnaround time. In contrast, despite a shorter turnaround time, rapid antigen testing largely suffers from a lower accuracy level. Thus, for the better management of the COVID-19 pandemic, it is necessary to develop rapid, high accuracy diagnostic technologies that can be used for large-scale detection of SARS-CoV-2 infection.
Lab-on-paper technology

In the current study, the scientists have developed an autonomous lab-on-paper device for multiplex gene detection of SARS-CoV-2. The method, which combines reverse transcription recombinase polymerase amplification (RT-RPA) and CRISPR–Cas12a detection, can simultaneously detect nucleoprotein and spike genes of SARS-CoV-2 in a single respiratory swab sample. As an internal control, the device uses human housekeeping RNAse P gene.

Regarding potential advantages, the device is capable of detecting 102 copies of viral RNA within one hour. Since two viral genes are simultaneously detected instead of a single gene, the device is expected to provide high accuracy information. Moreover, because of its simple and easy operational technique, testing with the device can be performed by any healthcare professional, making it suitable for large-scale detection of SARS-CoV-2 infection at the community level.

Operating procedure

To determine the performance of the device, the scientists collected 21 nasal swab samples from patients. Using commercially available kits, they processed these samples to isolate and purity nucleic acids. Afterward, they transferred the nucleic acid preparations to the cellulose-based paper membrane used in the device to detect SARS-CoV-2 infection. The results obtained from the device were comparable to those obtained from conventional RT-PCR testing.

The CRISPR technology used in the device is a highly sensitive and specific gene-editing technology that can alter the genome of an organism by targeting and cutting specific nucleic acid segments, such as DNA or RNA segments.

In the lab-on-paper method, CRISPR first locates the nucleoprotein and spike genes of SARS-CoV-2 and subsequently cuts them. Because of the cut, a fluorescent signal is produced on the device paper, indicating a positive test result. In addition, the device detects the human housekeeping RNAse P gene in order to validate the quality of the sample and the reliability of the result.

Potential advantages

The specialized cellulose-based paper membrane used in the device is hydrophilic in nature. Because of this property, the paper can transport samples that contain nucleic acids. This is highly advantageous as the test can be performed automatically once the sample is loaded. Moreover, because of certain specific formulations, the paper does not interfere with the biochemical reaction required for CRISPR to locate and cut the viral genes. This further reduces the risk of false negative/positive results.

By selecting specific genes of interest, the device can be used for detecting various other pathogens, including human immunodeficiency virus (HIV), human papillomavirus (HPV), or influenza virus.

The scientists have already applied for a provisional patent for the invention through the University of Connecticut Technology Commercialization Services. They are currently looking for an industrial partner to commercialize the device and expand its usage.

Journal reference:

Yin K. 2021. Autonomous lab-on-paper for multiplexed, CRISPR-based diagnostics of SARS-CoV-2. Lab on a Chip., ... ivAbstract
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