1. Diabetes mellitus is a chronic disease currently affecting more than 425 million people, of which one-third are people older than 65 years. In the UK, the number of people currently diagnosed with diabetes surpassed 3.8 million in 2019, with someone being diagnosed with the illness every two minutes (Diabetes.org figures). The prototype device being tested is a non-invasive blood glucose measurement system worn on the wrist. This would help people with diabetes manage their condition better and help prevent complications.

2. The main objectives of the research are:

   1. To determine how accurate and effective the Afon prototype non-invasive blood glucose measurement system is, as compared to a gold standard invasive method.
   2. To chart the Afon device's predicted blood glucose levels over time.

3. The study will be done with 30-50 patients. Eligible patients will have been diagnosed with diabetes (type 1 or 2) at least one year prior, be between 18 and 80 years old, and with a BMI between 18-35 kg/m2. For details of the full list of inclusion and exclusion criteria, see accompanying documentation.

4. The trial will be conducted at the Joint Clinical Research Facility (JCRF), Institute of Life Science 2, Swansea University, SA2 8PP.

5. Participants will attend the site for a total of 5 visits, one for screening, and four study visits, no more than 7 days apart. The study will run for one year.

Diabetes is a chronic disease currently affecting more than 425 million people worldwide. In the UK, the number of people currently diagnosed with diabetes surpassed 3.8 million in 2019, with someone being diagnosed with the illness every two minutes (Diabetes.org figures).By the end of this year, 4 million deaths will happen worldwide as a result of diabetes and its complications. These complications include renal failure, blindness, and amputation. It is well established clinically that good glycaemic control minimises the risk of long-term complications and improves morbidity and mortality. Current problems with frequent blood glucose testing are mainly due to patient intolerability. Many patients find finger prick testing for blood glucose levels to be painful, dislike using sharp objects and seeing their own blood. There is also a risk of infection, and in the long term, this practice can result in damage to the finger tissue. This is because the fingers have a high concentration of sensory nerve endings. Additionally, the current invasive blood glucose monitoring systems suffer limitations in terms of the requirement for continuous calibration and susceptibility to contamination by the growth of various living organisms.

The Afon technology device would be a gamechanger in terms of improving the quality of life of millions of patients and improve their chances to manage the condition without severe complications.

Inclusion Criteria:

Patient who has a documented Type 1 diagnosis (diagnosed under age 29), or Type 2 diabetes for more than one year (with negative GAD antibody test results) and who are willing and able to give informed consent for participation in the study Male or female patient Patient aged 18 to 80 years Patients with a BMI 18-35 kg/m2.

Exclusion Criteria:

The patient may not enter the study if ANY of the following apply:

Type 1 patients diagnosed after age 29 Type 2 patients with positive GAD antibody test results Patient with other active implantable medical devices, such as pacemakers Patient who is currently participating in another clinical trial for a pharmaceutical product Patient with a history of allergy to any materials used in the prototype sensors or materials used to stabilise the devices or cabling including Rocktape, double-sided tape and prosthetic adhesive Female patient who is pregnant or lactating

• Patient with any injury or infection of the wrist
• Patient who is unwilling or unable to attend each visit fasting from midnight (water is permitted freely) or fasting for a minimum of 3 hours (for an afternoon session)
• Patient who takes paracetamol or aspirin in the 24 hours preceding each visit
• Patient with clinically significant abnormal values in clinical chemistry, as judged by the PI
• Concurrent illness or a condition that may interfere with blood glucose levels (e. g. carcinoma, haematological disease, vasculitis, connective tissue disease, alcohol neuropathy)
• Patient who is incapable of giving informed legal consent
• Recent (1 month) episode of DKA, HONK or severe hypoglycaemia
• Patient on pramlintide (Symlin/Tripro-Amylin)
• Patient who attends the visit under the influence of alcohol or recreational drugs
• Patient with severe macrovascular disease - stroke, CVD, CKD stage IV -V Patient who fails screening for alcohol and recreational drugs use.

Trial participants will be patients who have agreed to help with the development of a non-invasive glucometer. Between thirty and fifty patients will be enrolled in this pilot study of prototype sensors. If any prototype sensor is of interest and promise, the number of patients exposed to it may be increased. Subjects who withdraw from the study will be replaced.

No data will be shared.