Novel microfluidic substrates based on electrospun poly(l-lactic acid) (PLLA) membranes were developed to increase the limited range of commercially available paper substrates, commonly used for the fabrication of microfluidic paper-based analytical devices (µPADs). PLLA advantageous properties include being biodegradable, biocompatible, easily processed in various tailored morphologies, and cost effective, among others. Oriented and non-oriented electrospun PLLA membranes were fabricated using electrospinning and the influence of fibre orientation, addition of hydrophilic additives and plasma treatments on the morphology, physicochemical properties and capillary flow rate were evaluated and compared with commercial Whatman paper. In addition, a proof of concept application based on the colorimetric detection of glucose in printed PLLA and paper-based microfluidic systems was also performed. The results show the potential of PLLA substrates for the fabrication of portable, disposable, ecofriendly and cost-effective microfluidic systems with controllable properties that can be tailored according to specific biotechnological application requirements, being a suitable alternative to conventional paper-based substrates.