# A Novel Earwax Self-Sampling Device: A Feasibility Study
## 1 Introduction  
There is a great need to develop new technologies to improve detection of common conditions, such as diabetes and depression. Earwax offers the possibility of extracting putative naturally occurring endogenous substances which could be detected for analysis. Several substances have been measured in earwax [1], which could be considered potential biomarkers for improving the detection of chronic diseases [2], like glycaemic abnormalities typical of diabetes. In this condition, currently the gold standard, raised levels of glycated haemoglobin (HbA\({}_{\text{IC}}\)) are imprecise in relation to chronic average of glucose levels [3]. Werecently found that earwax glucose offers almost 60% improved detection than HbA1c in measuring chronic glucose levels [4]. To date, no medical device has been designed for sampling earwax for analysis of endogenous substances. Earwax extraction is performed by clinicians in cases of external ear pathologies, in symptomatic impacted earwax [5], and to allow an unimpaired view of the tympan membrane [6]. The irrigation method of extraction, using the Reiner-Alexander syringe is one of the most common clinical extraction methods because it is safe and effective [5]. This is a costly procedure, impractical for routine use. Due to its bacteriostatic properties [7,8], similarly to other types of wax originating from the animal kingdom, such as honeycombs [9], human wax can easily be shipped to a lab for analysis by post without any specific requirements typical of many other biological samples such as blood, which are required to comply with strict regulations with regard to safety and quality control. Nonetheless, a comprehensive systematic review showed that, although some earwaxolytic solutions (containing mineral oils) may provide some success at removing earwax, no self-cleaning device, mechanic or electric, is as effective as the clinical extraction methods [10] and commercial availability is limited. Self-cleaning cotton swabs or \"buds\" popularly used to cleanse external ears and the auditive canal [11] can cause irritation, external ear diseases, and impacted earwax associated with canal bleeding [12,13]. Furthermore, by stimulating sensitive fibres surrounding the external auditive canal, cotton buds elicit various pleasurable visceral sensations, which might be associated with their continued use and potential abuse [14,15]. The amount of earwax extracted by these devices is also variable, as the method is not standardised. Hence, cotton buds would be better not be used for analytic applications of earwax. That is why we firstly designed a pre-clinical pilot study to test the safety of using a novel self-sampling plastic earwax device inside the ear, and the wax cleaning effect of different materials for removing artificial wax from a piece of animal skin. We used porcine skin because it has striking similarities to the human skin [16]. The results confirmed that the use of this novel device, given its incorporated break (Arrow 5 in Figure 1a-d) may be safe for using inside the ear and showed that an organic cellulose sponge that was impregnated with a specific concentration of a mineral oil solution (50%) [10] of Magnesium Chloride (MgCl2) may constitute the most effective tip for the novel device. While this sponge revealed the best abrasive and absorptive wax performance, the incorporated mineral oil solution confirmed its previously found earwaxolytic property [7] and reassured us that its appliance was going to be innocuous for the external auditory canal. It has previously shown prophylactic features for the skin [17]. A detailed diagram of the device can be found in Figure 1 and a 3D view of it can be seen in Figure 2.  
In this feasibility study we tested an inexpensive self-sampling new standardised device for obtaining earwax for analysis in comparison with a clinical method, based on the Reiner-Alexander syringe in healthy volunteers. We assessed reliability in wax sampling and safety of use of the new method.