title: The Use of a Pressure-Indicating Sensor Film to Provide Feedback upon Hydrogel-Forming Microneedle Array Self-Application In Vivo.
abstract: To evaluate the combination of a pressure-indicating sensor film with hydrogel-forming microneedle arrays, as a method of feedback to confirm MN insertion in vivo.
  
  
  
  Pilot in vitro insertion studies were conducted using a Texture Analyser to insert MN arrays, coupled with a pressure-indicating sensor film, at varying forces into excised neonatal porcine skin. In vivo studies involved twenty human volunteers, who self-applied two hydrogel-forming MN arrays, one with a pressure-indicating sensor film incorporated and one without. Optical coherence tomography was employed to measure the resulting penetration depth and colorimetric analysis to investigate the associated colour change of the pressure-indicating sensor film.
  
  
  
  Microneedle insertion was achieved in vitro at three different forces, demonstrating the colour change of the pressure-indicating sensor film upon application of increasing pressure. When self-applied in vivo, there was no significant difference in the microneedle penetration depth resulting from each type of array, with a mean depth of 237 μm recorded. When the pressure-indicating sensor film was present, a colour change occurred upon each application, providing evidence of insertion.
  
  
  
  For the first time, this study shows how the incorporation of a simple, low-cost pressure-indicating sensor film can indicate microneedle insertion in vitro and in vivo, providing visual feedback to assure the user of correct application. Such a strategy may enhance usability of a microneedle device and, hence, assist in the future translation of the technology to widespread clinical use.
authors.affiliation: School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK.
authors.forename: Eva M
authors.initials: EM
authors.lastname: Vicente-Pérez
authors.affiliation: School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK.
authors.forename: Helen L
authors.initials: HL
authors.lastname: Quinn
authors.affiliation: School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK.
authors.forename: Emma
authors.initials: E
authors.lastname: McAlister
authors.affiliation: School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK.
authors.forename: Shannon
authors.initials: S
authors.lastname: O'Neill
authors.affiliation: School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK.
authors.forename: Lezley-Anne
authors.initials: LA
authors.lastname: Hanna
authors.affiliation: School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK.
authors.forename: Johanne G
authors.initials: JG
authors.lastname: Barry
authors.affiliation: School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK. r.donnelly@qub.ac.uk.
authors.forename: Ryan F
authors.initials: RF
authors.lastname: Donnelly
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D016503:Drug Delivery Systems; D005260:Female; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D008845:Microinjections / Q000295:instrumentation / Q000379:methods*; D009339:Needles; D011247:Pregnancy; D011312:Pressure; D012646:Self Administration; D012867:Skin; D012869:Skin Absorption; D011795:Surveys and Questionnaires; D013552:Swine; D055815:Young Adult
chemical_list: D020136:Hydrogel, Polyethylene Glycol Dimethacrylate
keywords: application; feedback; microneedles; pressure-indicating sensor film; transdermal