Interfacial structure and property of eco-friendly carboxymethyl cellulose/poly(3-hydroxybutyrate-co-3-hydroxyvalerate) biocomposites

Towards high performance wood composites through interface customization with cellulose-based adhesive

How to efficiently produce high performance plywood is of particular interest, while its sensitivity to moisture is overcome. This paper presents a simple and scalable strategy for the preparation of high-performance plywood based on the chemical bonding theory; a wood interfacial functionalized platform (WIFP) based on (3-aminopropyl) triethoxysilane (APTES) was established. Interestingly, the APTES-enhanced dialdehyde cellulose-based adhesive (DAC-APTES) was able to effectively establish chemically active adhesive interfaces; the dry/wet shear strength of WIFP/DAC-APTES adhesive was 3.15/1.31 MPa, which was much higher than 0.7 MPa (GB/T 9846-2015). The prepared plywood showed excellent wood-polymer interface adhesion, which exceeded the force that the wood itself could withstand. In addition, the DAC-APTES adhesive exhibits moisture evaporation-induced curing behavior at room temperature and can easily support the weight of an adult weighing 65.7 Kg. This research provides a novel approach for functionalized interface design of wood products, an effective means to prepare high-performance plywood.

Development and Characterization of Electrospun Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Biopapers Containing Cerium Oxide Nanoparticles for Active Food Packaging Applications

Food quality is mainly affected by oxygen through oxidative reactions and the proliferation of microorganisms, generating changes in its taste, odor, and color. The work presented here describes the generation and further characterization of films with active oxygen scavenging properties made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) loaded with cerium oxide nanoparticles (CeO₂NPs) obtained by electrospinning coupled to a subsequent annealing process, which could be used as coating or interlayer in a multilayer concept for food packaging applications. The aim of this work is to explore the capacities of these novel biopolymeric composites in terms of O₂ scavenging capacity, as well as antioxidant, antimicrobial, barrier, thermal, and mechanical properties. To obtain such biopapers, different ratios of CeO₂NPs were incorporated into a PHBV solution with hexadecyltrimethylammonium bromide (CTAB) as a surfactant. The produced films were analyzed in terms of antioxidant, thermal, antioxidant, antimicrobial, optical, morphological and barrier properties, and oxygen scavenging activity. According to the results, the nanofiller showed some reduction of the thermal stability of the biopolyester but exhibited antimicrobial and antioxidant properties. In terms of passive barrier properties, the CeO₂NPs decreased the permeability to water vapor but increased the limonene and oxygen permeability of the biopolymer matrix slightly. Nevertheless, the oxygen scavenging activity of the nanocomposites showed significant results and improved further by incorporating the surfactant CTAB. The PHBV nanocomposite biopapers developed in this study appear as very interesting constituents for the potential design of new active organic recyclable packaging materials.

Advancing PHBV Biomedical Potential with the Incorporation of Bacterial Biopigment Prodigiosin

The quest for sustainable biomaterials with excellent biocompatibility and tailorable properties has put polyhydroxyalkanoates (PHAs) into the research spotlight. However, high production costs and the lack of bioactivity limit their market penetration. To address this, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was combined with a bacterial pigment with strong anticancer activity, prodigiosin (PG), to obtain functionally enhanced PHBV-based biomaterials. The samples were produced in the form of films 115.6-118.8 µm in thickness using the solvent casting method. The effects of PG incorporation on the physical properties (morphology, biopolymer crystallinity and thermal stability) and functionality of the obtained biomaterials were investigated. PG has acted as a nucleating agent, in turn affecting the degree of crystallinity, thermal stability and morphology of the films. All samples with PG had a more organized internal structure and higher melting and degradation temperatures. The calculated degree of crystallinity of the PHBV copolymer was 53%, while the PG1, PG3 and PG3 films had values of 64.0%, 63.9% and 69.2%, respectively. Cytotoxicity studies have shown the excellent anticancer activity of films against HCT116 (colon cancer) cells, thus advancing PHBV biomedical application potential.

Metabolic engineering for biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from glucose and propionic acid in recombinant Escherichia coli

In this study, novel polyhydroxyalkanoate (PHA)-associated genes (phaCp and phaABp) cloned from Propylenella binzhouense L72^T were expressed in Escherichiacoli cells for PHA production, and the recombinant strains were used to analyze PHA yields with various substrates. The highest poly (3-hydroxybutyrate-co-3-hydroxy-valerate) (PHBV) yield (1.06 g/L) and cell dry weight (3.31 g/L) in E. coli DH5α/ΔptsG-CpABp were achieved by using glucose and propionicacid as substrates. Structural verification of PHBV produced by E. coli DH5α/ΔptsG-CpABp was performed to evaluate the characteristics of the polymers using Fourier transform infrared spectroscopy and nuclear magnetic resonance analysis. In addition, the X-ray diffraction results showed improved crystallinity of PHBV, and thermogravimetric analysis showed good thermal stability of 298 °C. The above findings indicated that the expression of phaCp and phaABp genes resulted in improved PHBV synthesis activity, and the polymer had better performance at higher processing temperatures.

Recent advancements in 3D bioprinting technology of carboxymethyl cellulose-based hydrogels: Utilization in tissue engineering

3D printing technology has grown exponentially since its introduction due to its ability to print complex structures quickly and simply. The ink used in 3D printers is one of the most discussed areas and a variety of hydrogel-based inks were developed. Carboxymethyl cellulose (CMC) is derived from cellulose, which is a natural, biocompatible, biodegradable, and wildly abounded biopolymer. CMC is a very qualified candidate in the preparation of hydrogels because it has good solubility in water with multiple carboxyl groups. Various physical and chemical cross-linking methods and mechanisms have been used by researchers to prepare CMC-based hydrogels. Bioprinting is a powerful technology for tissue engineering applications that have been able to design and simulate different tissue and organs with digital control. Among many advantages, which were reported for bioprinting, its high throughput, as well as precise control of scaffolding and cells, is very valuable. Considering all these tips and capabilities, in this study, the methods of preparation and improvement of CMC-based hydrogels, applied 3D printer, and the latest inks designed using this biopolymer in terms of combination, features, and performance in tissue engineering are reported.