Antimicrobial and Conductive Nanocellulose-Based Films for Active and Intelligent Food Packaging

Abstract

Bacterial nanocellulose (BNC) is becoming an important substrate for engineering multifunctional nanomaterials with singular and tunable properties for application in several domains. Here, antimicrobial conductive nanocomposites composed of poly(sulfobetaine methacrylate) (PSBMA) and BNC were fabricated as freestanding films for application in food packaging. The nanocomposite films were prepared through the one-pot polymerization of sulfobetaine methacrylate (SBMA) inside the BNC nanofibrous network and in the presence of poly(ethylene glycol) diacrylate as cross-linking agent. The ensuing films are macroscopically homogeneous, more transparent than pristine BNC, and present thermal stability up to 265 °C in a nitrogen atmosphere. Furthermore, the films have good mechanical performance (Young’s modulus ≥ 3.1 GPa), high water-uptake capacity (450–559%) and UV-blocking properties. The zwitterion film with 62 wt.% cross-linked PSBMA showed bactericidal activity against Staphylococcus aureus (4.3–log CFU mL−1 reduction) and Escherichia coli (1.1–log CFU mL−1 reduction), and proton conductivity ranging between 1.5 × 10−4 mS cm−1 (40 °C, 60% relative humidity (RH)) and 1.5 mS cm−1 (94 °C, 98% RH). Considering the current set of properties, PSBMA/BNC nanocomposites disclose potential as films for active food packaging, due to their UV-barrier properties, moisture scavenging ability, and antimicrobial activity towards pathogenic microorganisms responsible for food spoilage and foodborne illness; and also for intelligent food packaging, due to the proton motion relevant for protonic-conduction humidity sensors that monitor food humidity levels.

Nanocellulose-Based Patches Loaded with Hyaluronic Acid and Diclofenac towards Aphthous Stomatitis Treatment

“…As anticipated, the hydrophilic BNC absorbs environmental humidity with values of 19 ± 2% after 24 h and 21 ± 2% after 48 h (Figure 6a). These results concur with data reported in previous studies [46,52].…”

Topical Drug Delivery Systems Based on Bacterial Nanocellulose: Accelerated Stability Testing

“…While BNC plasticized with 1% (w/v) of glycerol (a well-known humectant [43]) reached moisture-uptake values of 9.9 ± 3.1% at 60% RH/25 • C and 22.3 ± 0.4% at 75% RH/40 • C, the BNC containing 5% (w/v) glycerol reached a similar value at 60% RH/25 • C (10.3 ± 1.4%) but a higher moisture-uptake at 75% RH/40 • C (35.7 ± 1.9%). These values are analogous to those recently reported for a pure BNC membrane (without glycerol) at 98% RH for 48 h [15,16].…”

“…In the last decade, bacterial exopolysaccharide (viz. BNC) has attracted a great deal of interest in several areas, ranging from nanocomposite materials [11][12][13] to food packaging films [14,15] and conductive membranes for fuel cells [7,16], but, its main application is still in the biomedical field [17][18][19][20]. In fact, there are already BNC-based products being commercialized under the tradename 2 of 17 SYNTHECEL ® Dura Repair (implant, DePuy Synthes, USA), Epicitehydro (wound dressing, JeNaCell GmbH, Germany) and Celmat (wound dressing, BOWIL, Poland), which are FDA approved and/or CE-certified for biomedical applications [4].…”

Understanding the Structure and Dynamics of Nanocellulose-Based Composites with Neutral and Ionic Poly(methacrylate) Derivatives Using Inelastic Neutron Scattering and DFT Calculations

“…A tour through the kaleidoscopic portfolio of materials developed in the last decades, clearly shows that composite materials based on cellulose [1], and bacterial nanocellulose (BC) in particular [2], are quite relevant for myriad domains of applications [3][4][5]. In fact, the exopolysaccharide BC, which is biosynthesized by several non-pathogenic bacteria in the form of membranes with a tree-dimensional network of cellulose nanofibrils [6], has shown potential for drug delivery [7-9], wound healing [10,11], bone tissue engineering [12], antimicrobial materials [13], food and food packaging [14,15], water remediation [16,17] and fuel cells [5,18,19], just to mention some fields of application.…”

“…">IntroductionA tour through the kaleidoscopic portfolio of materials developed in the last decades, clearly shows that composite materials based on cellulose [1], and bacterial nanocellulose (BC) in particular [2], are quite relevant for myriad domains of applications [3][4][5]. In fact, the exopolysaccharide BC, which is biosynthesized by several non-pathogenic bacteria in the form of membranes with a tree-dimensional network of cellulose nanofibrils [6], has shown potential for drug delivery [7-9], wound healing [10,11], bone tissue engineering [12], antimicrobial materials [13], food and food packaging [14,15], water remediation [16,17] and fuel cells [5,18,19], just to mention some fields of application.In terms of production, BC-based nanocomposites can be prepared by in situ and ex situ methodologies [20], which already enabled the combination of BC with a vast array of synthetic polymers Molecules 2020, 25, 1689 2 of 16 (e.g., polyaniline [21] and Nafion [22]) and biopolymers (e.g., lactoferrin [23] and fucoidan [24]), as well as hybrid materials with metal oxides, metal sulphides and metal nanoparticles [4], and graphene and derivatives [25,26], with the aim of enhancing or adding novel properties to the ensuing materials [2]. Among the available methodologies, the in situ polymerization of monomers with, for instance, (metha)acrylate functional groups, is a simple top-down method that promotes the use of BC without altering its valuable and unique three-dimensional structure [2].…”