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Dr Keng Ng has paper published

Poly(lactic) acid/carbon nanotube composite microneedle arrays for dermal biosensing

Abstract

Minimally invasive, reliable and low-cost in vivo biosensors that enable real-time detection and monitoring of clinically rele-vant molecules and biomarkers can significantly improve patient healthcare.  Microneedle array (MNA) based electrochemi-cal sensors offer exciting prospects in this respect, as they can sample directly from the skin.  However, their acceptability is dependent on developing a highly scalable and cost-effective fabrication strategy.  In this work, we evaluated the potential for poly(lactic) acid/carboxyl-multiwalled carbon nanotube (PLA/f-MWCNT) composites to be developed into MNA’s and their effectiveness for dermal biosensing.  Our results show that MNA’s are easily made from solvent casted nanocomposite films by micromoulding.  A maximum carbon nanotube (CNT) loading of 6 wt% was attained with the current fabrication method.  The MNA’s were mechanically robust, being able to withstand axial forces up to 4 times higher than necessary for skin insertion.  Electrochemical characterisation of these MNA’s by differential pulse voltammetry (DPV) produced a linear current response towards ascorbic acid, with a limit of detection of 164.38 µM.  In situ electrochemical performance was assessed by DPV measurements in ex vivo porcine skin.  This showed active changes characterised by two oxidative peaks at 0.23 and 0.69 V, as a result of the diffusion of phosphate buffered saline.  The diagnostic potential of this waveform was further evaluated through a burn wound model.  This showed an attenuated oxidative response at 0.69 V.  Importantly, the impact of the burn could be measured at progressive distances from the burn site.  Overall, alongside the scalable fabrication strategy, the DPV results promise efficient electrochemical biosensors based on CNT nanocomposite MNA’s.

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Dr Keng Wooi Ng, Lecturer in Pharmaceutics

published on: 21 March 2019