CandyCollect, pictured here, could replace throat swabs to diagnose respiratory illnesses, including strep throat. Credit: Adapted from Analytical Chemistry, 2023, DOI: 10.1021/acs.analchem.3c00462
Receiving a lollipop at the end of a doctor’s visit is a time-honored tradition for young children. They would argue it’s the best part of the visit—perhaps the only part that is not frightening or intimidating.
Taking inspiration from this, chemists at the University of Washington have developed a “delicious” child-friendly device that can be used to capture saliva samples in the case of possible respiratory disease.
The “CandyCollect” sampling device looks and tastes just like a traditional lollipop—but there’s a lot more chemistry going on inside. The device features a spoon-like stick with a spiral-shaped groove carved into the top. This flattened end is covered with isomalt candy. Once inserted into the mouth, saliva and bacteria fill the groove, which is an open-fluidic channel designed to easily capture saliva and bacteria. Meanwhile, the isomalt candy flavoring functions as a built-in timer to ensure sufficient sampling time.
It's a win-win: children get to enjoy a lollipop, and doctors easily obtain the saliva they need to run diagnostic tests. More importantly, in a recent proof-on-concept study, the CandyCollect showed 100% concordance with today’s traditional collection methods, namely oral swabs and spit tubes.
Accurate, comfortable and delicious
For the study, published in Analytical Chemistry, researchers sent 28 healthy adults packages containing CandyCollect devices, oral swabs and spit tubes. The participants sampled themselves at home, completed usability and user preference surveys, and mailed the samples back to the University of Washington laboratory for analysis by qPCR.
In this proof-of-concept, the study authors tested for commensal bacteria Streptococcus
mutans and Staphylococcus aureus to allow broader participation, rather than focusing on the limited population of individuals with strep throat infection.
According to the results, when one or both of the conventional sampling methods detected a given bacterium, CandyCollect devices also detected the pathogen 100% of the time. Additionally, 87% of the participants who completed the study said CandyCollect was the “least disgusting and uncomfortable” sampling option. Sixty-five percent described it as the best method of saliva collection between the three options, and 70% said it was the best sampling experience.
Shelf-life and user experience
The study authors used fluorescence imaging to evaluate the effectiveness of CandyCollect at different time periods—0 days, 3 months, 4 months and 1 year.
Although there was a significant difference between the density per area in the images from 0 days and 1 year, the team reported only a 25% reduction in captured bacteria after 1 year of storage. An extended shelf-life is vital for commercial sampling devices since they may sit in a doctor’s office for an unknown time before use.
The researchers say there is potential to extend shelf-life even further.
“In the future, longer-lasting surface treatment can be used, such as treatments used for commercially available cell cultureware—which typically has a multiyear shelf life,” they write in their recently published paper.
Extended shelf-life is also important for patients since CandyCollect is user-friendly enough for point-of-care testing at-home or for use during a telemedicine appointment.
Larger future studies
The research team acknowledged this study was performed with a small sample size (n=14 sampled, n=26 surveyed), but the goal was to establish the potential of the CandyCollect device in healthy adults before progressing to individuals with respiratory illness. They already have launched additional studies with larger sample sizes in adults and children with respiratory illness, including one focusing on patients ages 5 to 17 with active group A streptococcus (GAS) pharyngitis, or strep throat.
“These additional studies include user feedback surveys, and we will determine if the feedback from these larger cohorts is consistent with the feedback from this initial cohort,” the scientists write in their paper. “[Regardless,] the present study opens up several exciting areas of future work as a new tool for at-home and in-clinic sampling that is intuitive, convenient and child-friendly.”