Novel Hyperbranched Dialdehyde Carboxymethyl Cellulose-Grafted Gelatin Films as Potential Natural Antibacterial Materials

Carboxymethyl cellulose (CMC) has potential applications in food packaging given its good processibility and biological properties. In this research, dialdehyde carboxymethyl cellulose (DCMC) was first modified with polyamidoamine (PAMAM G0) to synthesize hyperbranched dialdehyde carboxymethyl cellulose (HPD). Then, a novel hyperbranched dialdehyde carboxymethyl cellulose-grafted gelatin (HPD/Gs) film was obtained by the "one-pot" method. The structural characteristics, degree of cross-linking, thickness, swelling behavior, water solubility, water vapor permeability, surface morphology, hydrophilicity, mechanical strength, antibacterial properties, and biocompatibility of HPD/Gs were characterized by using Fourier transform infrared (FTIR), scanning electron microscopy energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray diffractometry (XRD), thermogravimetric analysis/derivative thermogravimetry (TGA/DTG), differential scanning calorimetry (DSC), and other analysis technologies. The results revealed that the prepared HPD/Gs film showed good thermal stability and mechanical properties. In particular, when the mass ratio of HPD to G was 1:1.5, the cross-linking degree, swelling behaviors, water vapor permeability (WVP), water contact angle, tensile strength, and elongation at break of the HPD/1.5G film reached 42.757%, 109.114%, 46.71 g·mm/m2·day·kPa (1 day), 115.4 ± 4.5°, 1.77 MPa, and 320.93%, respectively. Moreover, the HPD/Gs films had good cytocompatibility and antibacterial properties against Staphylococcus aureus and Escherichia coli. The research indicated that the designed HPD/Gs are a type of green antimicrobial material with potential value.