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Updated: Mar 26, 2026
Hollow Microneedle-based Sensor for Multiplexed Transdermal Electrochemical Sensing
Published on: June 1, 2012
Micropore closure kinetics are delayed following microneedle insertion in elderly subjects
Megan N Kelchen1, Kyle J Siefers1, Courtney C Converse1
1University of Iowa College of Pharmacy, Department of Pharmaceutical Sciences and Experimental Therapeutics, 115 S. Grand Ave, Iowa City, IA 52242, USA.
Abstract:
Transdermal delivery is an advantageous method of drug administration, particularly for an elderly population. Microneedles (MNs) allow transdermal delivery of otherwise skin-impermeable drugs by creating transient micropores that bypass the barrier function of the skin. The response of aging skin to MNs has not been explored, and we report for the first time that micropore closure is delayed in elderly subjects in a manner that is dependent upon MN length, number, and occlusion of the micropores. Twelve control subjects (25.6±2.8years) and 16 elderly subjects (77.3±6.8years) completed the study. Subjects were treated with MNs of 500μm or 750μm length, in arrays containing 10 or 50 MNs. Impedance measurements made at baseline, post-MN insertion, and at predetermined time points demonstrated that restoration of the skin barrier is significantly slower in elderly subjects under both occluded and non-occluded conditions. This was confirmed via calculation of the total permeable area created by the micropores (which would approximate the area available for drug delivery), as well as calculation of the micropore half-life. This pilot study demonstrates that longer timeframes are required to restore the barrier function of aged skin following MN insertion, suggesting that drug delivery windows could be longer following one treatment with a MN array.
Insights
Aging skin heals slower after microneedle (MN) insertion, delaying skin barrier restoration. This suggests longer drug delivery windows are possible for elderly individuals using MN technology.
Area of Science:
- Dermatology
- Biomedical Engineering
- Pharmaceutics
Background:
- Transdermal drug delivery offers advantages, especially for the elderly.
- Microneedles (MNs) create transient skin micropores for drug delivery, bypassing the skin's barrier function.
- The effect of aging skin on MN response remains largely unexplored.
Purpose of the Study:
- To investigate the response of aging skin to microneedle (MN) insertion.
- To determine if skin barrier restoration differs between young and elderly subjects after MN treatment.
- To assess the impact of MN parameters (length, number, occlusion) on aged skin healing.
Main Methods:
- A pilot study comparing young (25.6±2.8 years) and elderly (77.3±6.8 years) subjects.
- Microneedle arrays of 500μm or 750μm length with 10 or 50 MNs were used.
- Skin impedance measurements were taken at baseline, post-insertion, and over time under occluded and non-occluded conditions.
Main Results:
- Skin barrier restoration was significantly slower in elderly subjects compared to controls.
- Micropore closure time was dependent on MN length, number, and occlusion.
- Calculated total permeable area and micropore half-life confirmed delayed healing in aged skin.
Conclusions:
- Aged skin requires longer periods for barrier function restoration after MN insertion.
- The findings suggest potential for extended drug delivery windows with MNs in the elderly population.
- This study highlights the need to consider skin aging in MN-based transdermal delivery strategies.
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