The use of petroleum-based plastics in food packaging leads to various environmental impacts, while spoilage of food and misinterpretation of food-date labelling account for food insecurity; therefore, a biopolymer capable of indicating food edibility is prepared to resolve these issues. In this research, starch/polyaniline (starch/PANI) biopolymer film was synthesised and investigated as an ammonia sensor for potential application as intelligent food packaging. FT-IR and XRD were used to confirm the composition of the biopolymer films, while UV-Vis spectrometry was applied to identify the oxidation state of PANI in emeraldine form. PANI was successfully incorporated into the starch matrix, leading to better thermal stability (TGA) but decreasing the crystallinity of the matrix (DSC). The performance of the polymer-film sensor was determined through ammonia-vapour sensitivity analysis. An obvious colour change from green to blue of starch/PANI films was observed upon exposure to the ammonia vapour. Starch/PANI 0.4% is the optimum composition, having the best sensor performance with good linearity (R² = 0.9459) and precision (RSD = 8.72%), and exhibiting excellent LOD (245 ppm). Furthermore, the starch/PANI films are only selective to ammonia. Therefore, the starch/PANI films can be potentially applied as colourimetric ammonia sensors for intelligent food packaging.

Biopolymers that mimic the extracellular matrix are favourable in tissue engineering. However, the rapid degradation and the lack of mechanical and enzymatic stabilities of these biopolymers prompt researchers to composite different biopolymers. In this study, we aim to develop an acellular gelatin-chitosan-cellulose nanocrystal (GCCNC) scaffold as a potential wound dressing. The GCCNC mixture was homogenised via ultrasonication and the genipin crosslinking was performed by magnetic stirring. The mixture was then frozen at − 80 °C for 6 h and freeze-dried. The effects of different ratios of gelatin and chitosan with cellulose nanocrystals on the physiochemical properties, mechanical properties, and cellular biocompatibility were studied. Our results herein showed that G3C7CNC demonstrated a homogenous interconnected porous structure with a good porosity (67.37 ± 9.09%) and pore size (148.46 ± 48.68 µm), acceptable swelling ratio (1071.11 ± 140.26%), adequate water vapour transmission rate (315.59 ± 25.27 g/m²/day), low contact angle (70.21 ± 6.79°), and sufficient mechanical strength (modulus of 64.67 ± 12.42 MPa). The lower biodegradation rate in the G3C7CNC (0.06 ± 0.01 mg/hr) compared to G10CNC (0.48 ± 0.07 mg/hr) together with the absence of glass transition phenomenon indicated an increase in both enzymatic and thermal stabilities. Furthermore, G3C7CNC was non-cytotoxic and biocompatible with human epidermal keratinocytes (HEKs) and human dermal fibroblasts (HDFs). The presence of collagen type I and α-smooth muscle actin expression in HDFs, together with the expression of cytokeratin-14 in HEKs, demonstrated our scaffold’s ability to maintain normal skin physiological functions. Therefore, this study proposes that the fabricated GCCNC scaffold could serve as a potential acellular skin substitute in managing chronic wounds.

Intrinsically conducting polymers (ICPs) have been widely studied in various applications, such as sensors, tissue engineering, drug delivery, and semiconductors. Specifically, polyaniline (PANI) stands out in food industry applications due to its advantageous reversible redox properties, electrical conductivity, and simple modification. The rising concerns about food safety and security have encouraged the development of PANI as an antioxidant, antimicrobial agent, food freshness indicator, and electronic nose. At the same time, it plays an important role in food safety control to ensure the quality of food. This study reviews the emerging applications of PANI in the food industry. It has been found that the versatile applications of PANI allow the advancement of modern active and intelligent food packaging and better food quality monitoring systems.