Enhanced Antimicrobial Activity of Biocompatible Bacterial Cellulose Films via Dual Synergistic Action of Curcumin and Triangular Silver Nanoplates.

Curcumin and triangular silver nanoplates (TSNP)-incorporated bacterial cellulose (BC) films present an ideal antimicrobial material for biomedical applications as they afford a complete set of requirements, including a broad range of long-lasting potency and superior efficacy antimicrobial activity, combined with low toxicity. Here, BC was produced by Komagataeibacter medellinensis ID13488 strain in the presence of curcumin in the production medium (2 and 10%). TSNP were incorporated in the produced BC/curcumin films using ex situ method (21.34 ppm) and the antimicrobial activity was evaluated against Escherichia coli ATCC95922 and Staphylococcus aureus ATCC25923 bacterial strains. Biological activity of these natural products was assessed in cytotoxicity assay against lung fibroblasts and in vivo using Caenorhabditis elegans and Danio rerio as model organisms. Derived films have shown excellent antimicrobial performance with growth inhibition up to 67% for E. coli and 95% for S. aureus. In a highly positive synergistic interaction, BC films with 10% curcumin and incorporated TSNP have shown reduced toxicity with 80% MRC5 cells survival rate. It was shown that only 100% concentrations of film extracts induce low toxicity effect on model organisms' development. The combined and synergistic advanced anti-infective functionalities of the curcumin and TSNP incorporated in BC have a high potential for development for application within the clinical setting.

Monitoring In Vitro Extracellular Matrix Protein Conformations in the Presence of Biomimetic Bone-Regeneration Scaffolds Using Functionalized Gold-Edge-Coated Triangular Silver Nanoparticles.

In the cellular environment, high noise levels, such as fluctuations in biochemical reactions, protein variability, molecular diffusion, cell-to-cell contact, and pH, can both mediate and interfere with cellular functions. In this work, gold edge-coated triangular silver nanoparticles (AuTSNP) were validated as a promising new tool to indicate protein conformational transitions in cultured cells and to monitor essential protein activity in the presence of an optimized bone biomimetic chitosan-based scaffold whose rational design mimics the ECM as a natural scaffold. A chitosan-based scaffold formulation with hydroxyapatite (CS/HAp) was selected due to its promising features for orthopedic applications, including combined high mechanical strength biocompatibility and biodegradability. Functionalized AuTSNP-based tests with the model ECM protein, fibronectin (Fn), illustrate that the protein interactions can be clearly sensed over time through the local surface plasmon resonance (LSPR) technique. This demonstrates that AuTNSP are a powerful tool to detect protein conformational activity in the presence of biomimetic bone tissue regeneration scaffolds within a cellular environment that comprises a diversity of molecular cues.

Upcycling Biodegradable PVA/Starch Film to a Bacterial Biopigment and Biopolymer.

Meeting the challenge of circularity for plastics requires amenability to repurposing post-use, as equivalent or upcycled products. In a compelling advancement, complete circularity for a biodegradable polyvinyl alcohol/thermoplastic starch (PVA/TPS) food packaging film was demonstrated by bioconversion to high-market-value biopigments and polyhydroxybutyrate (PHB) polyesters. The PVA/TPS film mechanical properties (tensile strength (σu), 22.2 ± 4.3 MPa; strain at break (εu), 325 ± 73%; and Young's modulus (E), 53-250 MPa) compared closely with low-density polyethylene (LDPE) grades used for food packaging. Strong solubility of the PVA/TPS film in water was a pertinent feature, facilitating suitability as a carbon source for bioprocessing and microbial degradation. Biodegradability of the film with greater than 50% weight loss occurred within 30 days of incubation at 37 °C in a model compost. Up to 22% of the PVA/TPS film substrate conversion to biomass was achieved using three bacterial strains, Ralstonia eutropha H16 (Cupriavidus necator ATCC 17699), Streptomyces sp. JS520, and Bacillus subtilis ATCC6633. For the first time, production of the valuable biopigment (undecylprodigiosin) by Streptomyces sp. JS520 of 5.3 mg/mL and the production of PHB biopolymer at 7.8% of cell dry weight by Ralstonia eutropha H16 from this substrate were reported. This low-energy, low-carbon post-use PVA/TPS film upcycling model approach to plastic circularity demonstrates marked progress in the quest for sustainable and circular plastic solutions.

Progressing Ultragreen, Energy-Efficient Biobased Depolymerization of Poly(ethylene terephthalate) via Microwave-Assisted Green Deep Eutectic Solvent and Enzymatic Treatment.

Effective interfacing of energy-efficient and biobased technologies presents an all-green route to achieving continuous circular production, utilization, and reproduction of plastics. Here, we show combined ultragreen chemical and biocatalytic depolymerization of polyethylene terephthalate (PET) using deep eutectic solvent (DES)-based low-energy microwave (MW) treatment followed by enzymatic hydrolysis. DESs are emerging as attractive sustainable catalysts due to their low toxicity, biodegradability, and unique biological compatibility. A green DES with triplet composition of choline chloride, glycerol, and urea was selected for PET depolymerization under MW irradiation without the use of additional depolymerization agents. Treatment conditions were studied using Box-Behnken design (BBD) with respect to MW irradiation time, MW power, and volume of DES. Under the optimized conditions of 20 mL DES volume, 260 W MW power, and 3 min MW time, a significant increase in the carbonyl index and PET percentage weight loss was observed. The combined MW-assisted DES depolymerization and enzymatic hydrolysis of the treated PET residue using LCC variant ICCG resulted in a total monomer conversion of ≈16% (w/w) in the form of terephthalic acid, mono-(2-hydroxyethyl) terephthalate, and bis-(2-hydroxyethyl) terephthalate. Such high monomer conversion in comparison to enzymatically hydrolyzed virgin PET (1.56% (w/w)) could be attributed to the recognized depolymerization effect of the selected DES MW treatment process. Hence, MW-assisted DES technology proved itself as an efficient process for boosting the biodepolymerization of PET in an ultrafast and eco-friendly manner.

Large area CMOS bio-pixel array for compact high sensitive multiplex biosensing.

A novel CMOS bio-pixel array which integrates assay substrate and assay readout is demonstrated for multiplex and multireplicate detection of a triplicate of cytokines with single digit pg ml(-1) sensitivities. Uniquely designed large area bio-pixels enable individual assays to be dedicated to and addressed by single pixels. A capability to simultaneously measure a large number of targets is provided by the 128 available pixels. Chemiluminescent assays are carried out directly on the pixel surface which also detects the emitted chemiluminescent photons, facilitating a highly compact sensor and reader format. The high sensitivity of the bio-pixel array is enabled by the high refractive index of silicon based pixels. This in turn generates a strong supercritical angle luminescence response significantly increasing the efficiency of the photon collection over conventional farfield modalities.