Synthesis of eco-friendly multifunctional dextran microbeads for multiplexed assays

There has been an increasing demand for simultaneous detection of multiple analytes in one sample. Microbead-based platforms have been developed for multiplexed assays. However, most of the microbeads are made of non-biodegradable synthetic polymers, leading to environmental and human health concerns. In this study, we developed an environmentally friendly dextran microbeads as a new type of multi-analyte assay platform. Biodegradable dextran was utilized as the primary material. Highly uniform magnetic dextran microspheres were successfully synthesized using the Shirasu porous glass (SPG) membrane emulsification technique. To enhance the amount of surface functional groups for ligand conjugation, we coated the dextran microbeads with a layer of dendrimers via a simple electrostatic adsorption process. Subsequently, a unique and efficient click chemistry coupling technique was developed for the fluorescence encoding of the microspheres, enabling multiplexed detection. The dextran microbeads were tested for 3-plex cytokine analysis, and exhibited excellent biocompatibility, stable coding signals, low background noise and high sensitivity.

High degradation bioplastics chitosan-based from scale waste of milkfish (Chanos chanos)

Bioplastic that is synthesized from natural materials such as chitosan is a renewable solution to reduce plastic waste in the environment because they are easily decomposed. In this study, chitosan (CS) was extracted from Milkfish scales waste to produce composite bioplastic CS/PVA/PEG to determine the effect of CS on the mechanical properties and degradation time. The average particle size of chitin is 8.5 μm and crystallinity of 57.18 % and for CS, the particle size is 3.5 μm and crystallinity of 64.94 %. The degree of deacetylation of CS is 84.1 % which met the quality standard of Indonesian national standard (SNI) Number: 7949:2013. The tensile strength of bioplastics for 0.5 g CS of 0.21 MPa increases to 0.24 MPa for 2 g CS in composite bioplastics CS/PVA/PEG. The biodegradation performance of bioplastic samples takes 72 h to completely decompose in soil for CS-based and in seawater for chitin-based, means that highly recommended to develop in future.

Microplastic accumulation in bivalves collected from different coastal areas of Vietnam and an assessment of potential risks

Microplastic (MP) pollution is an emerging problem in many areas around the world and in coastal areas of Vietnam, requiring more studies dedicated to the accumulation of this pollutant in the food chain as well as its potential risk to human health. This study investigated MP levels in tissues of five common bivalve species collected from aquaculture areas along the coast of Vietnam. MPs were found in all bivalve samples, with average values of 10.84 ± 2.61 items/individual or 2.40 ± 1.34 items/g wet weight. Impacts of feeding habits of bivalves showed influences on MP abundance in the samples. Fibers were the dominant shape of MPs recorded, most of which accumulated in the gills and digestive glands of all bivalve samples, with the majority falling within the size range of 300-2000 µm. MPs found in all studied species had relatively similar chemical compositions, mainly composed of polypropylene (PP) and polyethylene (PE). In this study, a diverse diet consisting of different bivalve species and detailed data on the consumption rate of these species were used to assess the human health risk of MPs dedicated to the coastal communities of Vietnam. The results suggested a significant part of MP uptake by human could be via bivalve consumption, in which removing viscera and proper depuration should be applied prior to eating, thereby reducing the risk.

Effect of an Acinetobacter pittobacter on low-density polyethylene

Low-density polyethylene (LDPE) is a major cause of persistent and long-term environmental pollution. In this study, we report the successful isolation of an efficient LDPE degrading bacterial strain from the wastewater sediment of an agricultural land film recycling plant and identified and designated it as Acinetobacter sp. LW-1, respectively. The surface analyses including scanning electron microscopy (SEM) and atomic force microscopy (AFM) of LW-1-treated samples revealed the existence of appreciable pits and cavities on the facet of PE film, while the formation of carbonyl group was also verified by XPS and FTIR. Moreover, water contact angle assay substantiated the chemical transformation of the LDPE film from hydrophobic to hydrophilic transition after treatment with LW-1. In addition, co-incubation of LDPE film and Acinetobacter sp. LW-1 at 35 °C for 90 days significantly decreased the weight of LDPE film with an optimal weight loss of 15 ± 0.85%. This work enriches the LDPE degradation bacterial library and shows the tremendous potential of Acinetobacter sp. LW-1 to be used in the degradation of LDPE waste.

Enhanced Functional Properties of Bioplastic Films Using Lignin Nanoparticles from Oil Palm-Processing Residue

The development of bioplastic materials that are biobased and/or degradable is commonly presented as an alleviating alternative, offering sustainable and eco-friendly properties over conventional petroleum-derived plastics. However, the hydrophobicity, water barrier, and antimicrobial properties of bioplastics have hindered their utilization in packaging applications. In this study, lignin nanoparticles (LNPs) with a purification process were used in different loadings as enhancements in a Kappaphycus alvarezii matrix to reduce the hydrophilic nature and improve antibacterial properties of the matrix and compared with unpurified LNPs. The influence of the incorporation of LNPs on functional properties of bioplastic films, such as morphology, surface roughness, structure, hydrophobicity, water barrier, antimicrobial, and biodegradability, was studied and found to be remarkably enhanced. Bioplastic film containing 5% purified LNPs showed the optimum enhancement in almost all of the ultimate performances. The enhancement is related to strong interfacial interaction between the LNPs and matrix, resulting in high compatibility of films. Bioplastic films could have additional advantages and provide breakthroughs in packaging materials for a wide range of applications.

Nanocellulose-Based Composite Materials Used in Drug Delivery Systems

Nanocellulose has lately emerged as one of the most promising “green” materials due to its unique properties. Nanocellulose can be mainly divided into three types, i.e., cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and bacterial cellulose (BC). With the rapid development of technology, nanocellulose has been designed into multidimensional structures, including 1D (nanofibers, microparticles), 2D (films), and 3D (hydrogels, aerogels) materials. Due to its adaptable surface chemistry, high surface area, biocompatibility, and biodegradability, nanocellulose-based composite materials can be further transformed as drug delivery carriers. Herein, nanocellulose-based composite material used for drug delivery was reviewed. The typical drug release behaviors and the drug release mechanisms of nanocellulose-based composite materials were further summarized, and the potential application of nanocellulose-based composite materials was prospected as well.

Isolation and identification of low-density polyethylene degrading novel bacterial strains

Plastics are usually made up of low-density polyethylene (LDPE) that serve as the environmental nuisance. The recalcitrant nature of plastics is a huge concern, whereas the increasing demand has made it difficult to handle the plastic waste that eventually leads to plastic pollution. In recent years, due to increasing demand and high pressure for its safe disposal, plastic biodegradation has gained a lot of attention. In the current study, four bacterial strains were isolated from the solid-waste dumpsites of Faisalabad, Pakistan, using enrichment culture technique. The isolated bacterial strains were capable of growing on media having polystyrene as the sole carbon source. Based on 16S rRNA gene sequencing and phylogenetic analysis of the isolated strains Serratia sp., Stenotrophomonas sp. and Pseudomonas sp. were identified as the potential strains for the biodegradation of LDPE. Serratia sp. resulted in 40% weight loss of the LDPE plastic pieces after 150 days of treatment. Stenotrophomonas sp. and Pseudomonas species resulted in 32 and 21% weight loss of the treated piece of plastics (LDPE), respectively. Polyethylene pieces were characterized by Fourier-transform infrared spectroscopy (FTIR) analysis before and after biodegradation. The FTIR spectra indicated that the isolated bacterial strains have a good potential to degrade LDPE. Future studies are required to investigate the bacterial genetic makeup, mechanisms of LDPE biodegradation and the factors that can enhance the biodegradable characteristics of these indigenously isolated bacterial strains.