Objective:

Review developments in wearable diagnostic systems and assess their potential applications and barriers to clinical use.

Approach:

• Scope: The review examines skin patches, smart contact lenses, and electronic textiles that monitor molecular biomarkers and physiological signals.
• Technology: It discusses biosensors, flexible-device manufacturing, integrated data processing and wireless communication, and AI-based interpretation.

Key Findings:

• Wearables can continuously measure biomarkers in sweat, tears, or saliva, as well as signals such as electrical activity, movement, and cardiovascular function.
• Potential applications span diabetes, cardiovascular disease, neurological disorders, cancer, and inflammatory conditions; continuous glucose monitoring is cited as an established example.
• AI could identify patterns across measurements and deviations from an individual's usual physiological state.
• Reliability may be affected by prolonged use, movement, environmental conditions, and individual differences.
• Many wearable technologies have not been adequately compared with established diagnostic methods, and analytical sensitivity alone does not establish clinical equivalence.

Interpretation:

The authors describe wearable diagnostics as potential complements to conventional testing, not replacements. They identify standardized validation, reliable long-term performance, and regulatory oversight as necessary for clinical translation.

Limitations:

• Sensor performance may deteriorate during prolonged use.
• Movement, environmental conditions, and individual differences can affect measurement reliability.
• The clinical meaning of biomarker concentrations in sweat and other fluids requires further investigation.
• Many technologies lack adequate comparison with established diagnostic methods.

Conclusion:

The review concludes that wearable diagnostics require further validation and oversight before broad clinical adoption.

Sources:

• Nano-Micro Letters review (as described in the provided context)