*2.1. Reagent and Materials*

Hexadecyltrimethyl ammonium bromide (CTA) and nanocrystalline cellulose (NCC) were purchased from Sigma Aldrich (St. Louis, MO, USA). Carboxyl-graphene quantum dots (CGQD) solution (0.1 wt%) was purchased from ACS Material (Pasadena, CA, USA) and glucose was purchased from R&M Marketing (Essex, UK).
