Bioactive Electrospun Polycaprolactone Films with Gallic Acid-Loaded Mesoporous Silica Nanoplatelets for Enhanced Seed Germination

Abstract

Enhancing seed germination and promoting early seedling growth are among the primary objectives in advancing agricultural productivity. To address these needs, this study developed electrospun nanofiber films composed of polycaprolactone (PCL) incorporating gallic acid (GA)-loaded, amine-functionalized mesoporous silica nanoplatelets (H-MSN-NH₂@GA). The mesoporous silica nanoplatelets (H-MSNs) with a hexagonal morphology were synthesized by using a sol–gel approach. These nanoplatelets were subsequently functionalized with amine groups using 3-(2-aminoethylamino)propyltrimethoxysilane (AAPTS) to enable efficient GA loading. The functionalized and nonfunctionalized H-MSNs, both with and without GA, were incorporated into a PCL matrix to produce uniform nanofiber films via electrospinning. A series of films with varying compositions were fabricated to evaluate the effect of the additive content on functionality. All resulting films displayed consistent hydrophobic characteristics and high water vapor transmission rates, exceeding 3000 g/m²/day. This indicated that incorporation of the silica-based additives did not significantly alter the films’ permeability or surface wettability. Tensile tests revealed distinct variations in maximum force and tensile displacement among the five samples, indicating composition-dependent mechanical properties. At 72 h, the 10% H-MSN-NH₂@GA/PCL film achieved 100% germination for corn seeds and a 70% higher germination rate for bean seeds compared to the control group. Root length analysis showed that 10% H-MSN/PCL and 1% H-MSN-NH₂@GA/PCL promoted corn root growth, while 10% H-MSN-NH₂@GA/PCL had an inhibitory effect. For bean seeds, root elongation was enhanced by 10% H-MSN/PCL, 1% H-MSN-NH₂@GA/PCL, and 10% H-MSN-NH₂@GA/PCL. These findings provide valuable insights into the effects of mesoporous silica nanoplatelets with and without GA in electrospun fiber films, offering a sustainable and functional alternative to conventional germination substrates.