Gelatin-Based Functional Biopolymer: Structural Characterization, Antimicrobial Activity, Biofilm Control, and Stability Evaluation

Abstract

Gelatin, a biodegradable and biocompatible biopolymer, has promising applications in biomedical, environmental, and food systems. In this study, gelatin was synthesized and characterized for its structural, physicochemical, and antimicrobial properties. FTIR analysis confirmed characteristic functional groups, including N-H/O-H stretching at 3400.0 cm⁻¹ (amide A), C-H stretching at 2920.0 cm⁻¹, and amide I and II bands at 1640.0 cm⁻¹ and 1510.0 cm⁻¹, indicating preserved peptide linkages. XRD revealed a semi-crystalline structure with peaks at 2θ ≈ 7.0 – 8.0° and 20.0 – 22.0° and crystallite sizes of 8.0 – 18.0 nm, while SEM showed a compact, homogeneous polymeric matrix with minor micro-textural features. Zeta potential analysis indicated a moderately negative surface charge (-12.8 mV) with uniform distribution, reflecting moderate colloidal stability.
The synthesized gelatin exhibited time-dependent antibacterial activity, reducing Staphylococcus aureus from 7.20 to 3.70 log₁₀ CFU/mL and Bacillus subtilis from 7.15 to 3.50 log₁₀ CFU/mL, while Escherichia coli decreased from 7.30 to 4.30 log₁₀ CFU/mL and Pseudomonas aeruginosa from 7.28 to 4.90 log₁₀ CFU/mL over 24 h. Biofilm inhibition reached 72.0%, and eradication of preformed biofilms was 65.0%, confirmed via live/dead staining. The gelatin retained over 70.0% antibacterial activity after three reuse cycles and maintained functional stability after 30 and 60 days of storage.
These results demonstrate that the synthesized gelatin possesses stable molecular structure, uniform morphology, effective antimicrobial and antibiofilm properties, and good reusability and storage stability. This makes it a promising material for biopolymer nanocomposites, antimicrobial coatings, wound dressings, biomedical scaffolds, and food packaging applications.