Reconstruction of biorefinery lignin into nanoparticles with controlled morphology and structure.

Lignin nanoparticles (LNPs) exhibit application potential in fields such as ultraviolet (UV) shielding, antioxidant materials, and water purification owing to their versatile chemical structure. However effective, nontoxic solvent-based strategies to synthesize LNPs with diverse morphologies have not been reported. This study presents a continuous biorefinery method to produce monodisperse LNPs with diverse morphologies from isopropanol-solubilized lignin (IPA-lignin).

One-pot synthesis of monodisperse silver-lignin particles: Enhanced antibacterial agents against antibiotic-resistant bacteria.

Lignin-based supports for metal nanoparticles (NPs) have attracted significant attention due to their abundant functional groups that facilitate NPs loading. However, many studies involve a two-step process: fabricating lignin particles and then reducing metal ions to NPs using physical energy consumption or chemical reduction. A one-step in-situ reduction method for NP synthesis on carrier surfaces, eliminating energy consumption, is needed for environmentally friendly and sustainable approach.

Palmitic acid-mediated modulation of crystallization dynamics in amylose microparticle formation: From spherical to macaron and disc shapes.

Here, we investigated the complexation of short chain amylose (SCAs) and palmitic acid (PA), serving as polymeric building blocks that alter the selectivity and directionality of particle growth. This alteration affects the shape anisotropy of the particles, broadening their applications due to the increased surface area. By modifying the concentration of PA, we were able to make spherical, macaron, and disc-shaped particles, demonstrating that PA acts as a structure-directing agent.

Catalyst-recirculating system in steam explosion pretreatment for producing high-yield of xylooligosaccharides from oat husk.

We propose a closed-loop pretreatment process, wherein volatiles produced during steam explosion pretreatment were recovered and reintroduced as acid catalysts into the pretreatment system. The volatiles were separated through a drastic decompression process followed by a steam explosion process and recovered as a liquified catalyst (LFC) through a heat exchanger. The LFC effectively served as an acid catalyst for hemicellulose hydrolysis, significantly decreasing residence time from 90 min to 30 min to achieve 80 % conversion yield at 170 °C.

Label-free detection of glutathione and glutathione disulfide in biological fluid by using an alpha-hederin nanopore.

Glutathione (GSH) is indispensable for maintaining redox homeostasis in biological fluids and serves as a key component in cellular defense mechanisms. Accurate assessment of GSH relative to its oxidized counterpart, glutathione disulfide (GSSG), is critical for the early diagnosis and understanding of conditions related to oxidative stress. Despite existing methods for their quantification, the label-free and simultaneous measurement of GSH and GSSG in biological fluid presents significant challenges.

Investigation of lignin substructures participating in self-assembly for the synthesis of monodisperse lignin spherical particles.

The intricate structure of lignin, characterized by a mix of hydrophilic components and hydrophobic structures from its aliphatic and aromatic constituents, poses challenges in creating monodisperse particles. This is due to the need for precise modulation of self-assembly kinetics. Herein, we explore a correlation between the substructure of lignin and its capacity for self-assembly.

β-Ketoadipic acid production from poly(ethylene terephthalate) waste chemobiological upcycling.

The upcycling of poly(ethylene terephthalate) (PET) waste can simultaneously produce value-added chemicals and reduce the growing environmental impact of plastic waste. In this study, we designed a chemobiological system to convert terephthalic acid (TPA), an aromatic monomer of PET, to β-ketoadipic acid (βKA), a C6 keto-diacid that functions as a building block for nylon-6,6 analogs. Using microwave-assisted hydrolysis in a neutral aqueous system, PET was converted to TPA with Amberlyst-15, a conventional catalyst with high conversion efficiency and reusability.

Modulation of the peroxidase-like activity of iron oxide nanoparticles by surface functionalization with polysaccharides and its application for the detection of glutathione.

Here, we employed three polysaccharides, such as dextran, hyaluronic acid, and chitosan, for surface modification of iron oxide nanoparticles (IONPs) and carried out in-depth investigation to elucidate the effect of surface functionalities on the peroxidase (POD) like activity of IONPs. The affinity of substrates to the catalytic site of IONPs was found to be determined by the surface functional groups and hydration layer of polysaccharide coating on the surface of IONPs. The role of hydration layer was further confirmed by the results that the POD-like activity of IONPs coated with a certain polysaccharide having higher water holding capacity was significantly enhanced by salting-out reagent, such as ammonium chloride that is known to reduce the thickness of hydration layer.

Synthetic Ligand-Coated Starch Magnetic Microbeads for Selective Extraction of Food Additive Silicon Dioxide from Commercial Processed Food.

The amorphous form of silicon dioxide has long been regarded as a safe food additive (E551) that is widely used in commercially processed food as an anticaking agent. However, starting with titanium dioxide, there have been growing safety concerns regarding to the use of nanoscale silicon dioxide particles in food as food additives. The size, morphology, and chemical properties of inorganic food materials are important parameters to determine its potential toxicity.

Paper-based colorimetric detection of pathogenic bacteria in food through magnetic separation and enzyme-mediated signal amplification on paper disc.

Herein, we report a colorimetric sensing system for the detection of highly virulent bacteria, Escherichiacoli O157:H7, in sausage by utilizing magnetic separation and enzyme-mediated signal amplification on paper disc. For magnetic separation, Poly-l-lysine coated starch magnetic particles (PLL@SMPs) were synthesized and utilized for the separation and concentration of the bacteria in sample suspension. Horseradish peroxidase-conjugated antibody (HRP-Antibody) and 3,3',5,5'- tetramethylbenzidine (TMB) were employed for the specific signal amplification in the presence of target bacteria.

Topological analysis of single-stranded DNA with an alpha-hederin nanopore.

Nanopores have been emerged as a powerful tool for analyzing the structural information and interactional properties of a range of biomolecules. The spatial resolution of nanopore is determined by the diameter and effective thickness of its constriction region, but the presence of vestibule or stem structure in protein-based nanopore could negatively affect the sensitivity of the nanopore when applied for genome sequencing and topological analysis of DNA. Recently, alpha-hederin (Ah) has been reported to form a sub-nanometer scale pore structure in lipid membrane.

Gold Nanoparticle-Coated Starch Magnetic Beads for the Separation, Concentration, and SERS-Based Detection of O157:H7.

Here, we report gold nanoparticle-coated starch magnetic beads (AuNP@SMBs) that were prepared by in situ synthesis of AuNPs on the surface of SMBs. Upon functionalization of the surface with a specific antibody, the immuno-AuNP@SMBs were found to be effective in separating and concentrating the target pathogenic bacteria, O157:H7, from an aqueous sample as well as providing a hotspot for surface-enhanced Raman scattering (SERS)-based detection. We employed a bifunctional linker protein, 4× gold-binding peptide-tagged Streptococcal protein G (4GS), to immobilize antibodies on AuNP@SMBs and AuNPs in an oriented form.

Paper-Based Radial Chromatographic Immunoassay for the Detection of Pathogenic Bacteria in Milk.

Here, a paper-based radial flow chromatographic immunoassay (RFCI) employing gold nanoparticles (AuNPs) as chromatic agents was developed for the detection of O157:H7 in whole milk. A 4-repeated gold-binding peptide-tagged (4GBP) streptococcal protein G (SPG) fusion protein was constructed as a bifunctional linker to immobilize antibodies on the surface of AuNPs with a well-oriented form based on the specific affinity of GBP and SPG to the gold and Fc portion of the antibody, respectively. 4GS@AuNPs prepared with the bifunctional linker protein exhibited excellent colloidal stability even at high salt concentrations of up to 500 mM, which is a critical requirement for its application to a broad range of biological and food samples.

Colorimetric Determination of the Activity of Starch-Debranching Enzyme via Modified Tollens' Reaction.

Nelson-Somogyi and 3,5-dinitrosalicylic acid (DNS) assays are the classical analytical methods for the determination of activity of starch-debranching enzymes, however, they have a narrow detection range and do not adapt to the quantitative measurement of linear polysaccharides. Herein, we developed a simple and accurate colorimetric assay for determining the activity of starch-debranching pullulanase through the modified Tollens' reaction in combination with UV irradiation. Silver nanoparticles (AgNPs) were formed by reducing aldehyde groups in short-chain glucans (SCGs) generated by debranching of waxy maize starch using pullulanase through the modified Tollens' reaction.

Molecular Rearrangement of Glucans from Natural Starch To Form Size-Controlled Functional Magnetic Polymer Beads.

Herein, we report a fairly simple and environmentally friendly approach for the fabrication of starch-based magnetic polymer beads (SMPBs) with uniform shape and size through spontaneous rearrangement of short-chain glucan (SCG) produced by enzymatic debranching of waxy maize starch. The paramagnetic materials, dextran-coated iron oxide nanoparticles (Dex@IONPs), were readily incorporated into the starch microstructure and rendered a superparamagnetic property to the SMPBs. The morphology and size of resulting SMPBs turned out to be modulated by Dex@IONPs in a concentration-dependent manner, of which Dex@IONPs was assumed to be acting as a seed inducing the epitaxial crystallization of SCG and further transforming it into homogeneous microparticles.