Molecularly imprinted polymer-based biosensor on microneedles for monitoring of glucose and creatinine

Diabetes mellitus is often diagnosed with blood glucose concentration by invasive or enzymatic methods, which indicates patients' health. The accuracy of the enzyme-based electrochemical glucose sensors may be limited due to strip manufacturing variances, strip storage, and aging. Herein, a microneedle(MN) molecularly imprinted polymer (MIP) approach was used to develop an electrochemical non-enzymatic sensor to determine the glucose levels in the interstitial fluid, facilitating a simple sampling fluid under the skin without bleeding. A cross-shaped microneedles patch was fabricated via photolithography using mixed acrylated epoxidized soybean oil and methyl methacrylic acid (AESO/MAA) resin. The gold nanoparticles on the MN patch were coated using an electroless plating and sputtering method, and MIP membrane was deposited on the microneedle gold electrodes. 3-(acrylamido)phenylboronic acid (3APBA) functional monomer, methacrylic acid (MAA) monomer, ethylene glycol dimethacrylate(EGDMA) cross-linker, and 2,2-dimethoxy-2-phenylacetophenone (DMPA) initiator were utilized in the presence of a glucose or creatinine template for the processing of electropolymerization or spin coating. After the removal of the templets, MIP electrodes created highly selective cavities. Cyclic voltammetry(CV), electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and square wave voltammetry (SWV) techniques were employed for the electrochemical measurements with potassium ferrocyanide as a redox probe in phosphate buffer saline. Under optimum conditions, the microneedle MIP sensor could effectively detect glucose in a working range from 50 to 800 mg/dL, and creatinine in a working range from 0.1 to 2 mg/dL, even under-heated sensor at 50 ºC before testing. Consequently, this work has demonstrated a simple and effective sensing platform to avoid the limitation of the enzyme-based strip; it is a promising tool for the future evolution of accurate and reliable non-invasive diagnosis.