Polylactic Acid Biocomposites Reinforced with Nanocellulose Fibrils with High Lignin Content for Improved Mechanical, Thermal, and Barrier Properties

Lignin, the second most abundant natural polymer on earth after cellulose, contains both hydrophilic and hydrophobic groups. In this study, the use of nanocellulose fibrils with high lignin content (NCFHL) has been explored to make polylactic acid (PLA) biocomposites with excellent mechanical, thermal, and barrier properties. Different amounts of NCFHL aqueous suspensions (5–20 wt %) were wet mixed with PLA latex to form composite films by casting and hot pressing. The presence of lignin imparted a strong compatibility between NCFHL and the PLA matrix, which overcame the major issue of poor interfacial bonding associated with nanocellulose fibrils without lignin previously reported by literature studies. Atomic force microscope infrared spectroscopy (AFM-IR) characterization results showed an effective coupling between NCFHL and PLA at the nanoscale. With 5–10 wt % of NCFHL additions to the PLA matrix, a significant improvement in mechanical, thermal, and water vapor barrier properties was observed for the resulting biocomposites. The addition of 10 wt % of the NCFHL increased the modulus and strength by 88% and 111%, respectively, and the water vapor transmission rate was reduced by 52%, compared to neat PLA

Effects of Lignin Content on Mechanical and Thermal Properties of Polypropylene Composites Reinforced with Micro Particles of Spray Dried Cellulose Nanofibrils

In this work, the use of microsized cellulosic particles obtained from spray dried cellulose nanofibrils with high lignin content (>20 wt %) were explored for the first time as reinforcement in polypropylene (PP) composites. Their effect was compared with the results from PP composites reinforced by cellulosic particles of spray dried cellulose nanofibrils with a low lignin content (<5 wt %). Cellulose nanofibrils with diameters less than 100 nm were obtained by mechanically fibrillating unbleached and bleached cellulosic fibers obtained from tree bark after alkaline extraction for removal of extractive. These cellulose nanofibrils were then spray dried to microsized high lignin content cellulose particles (HLCP) and low lignin content cellulose particles (LLCP), respectively. The presence of a large amount of lignin in the nanofibrils alleviated the degree of aggregation during the spray drying process. Both HLCP and LLCP were melt compounded with polypropylene (PP) to make composites films with different cellulosic particle loading levels. Compared to LLCP, HLCP significantly improved water repellency, thermal stability, and tensile properties of the composites films. With an addition of 5 wt % HLCP in PP, the tensile strength and modulus of the composites increased by 25.3% and 41.5% compared to neat PP, respectively. However, composites containing 5 wt % LLCP experienced a decrease in tensile strength by nearly 23.0% instead. Moreover, compatibilizing and stabilizing effects of lignin were also observed during the processing of the composites. This study demonstrated strong potential of HLCP as biobased reinforcement filler in plastic composites

Dual-targeting for brain-specific drug delivery: synthesis and biological evaluation

<p>Ibuprofen is one of the most potent non-steroid anti-inflammatory drugs (NSAIDs) and plays an important role in the treatment of neurodegenerative diseases. However, its poor brain penetration and serious side effects at therapeutic doses, has hindered its further application. Thus, it is of great interest to develop a carrier-mediated transporter (CMT) system that is capable of more efficiently delivering ibuprofen into the brain at smaller doses to treat neurodegenerative diseases. In this study, a dual-mediated ibuprofen prodrug modified by glucose (Glu) and vitamin C (Vc) for central nervous system (CNS) drug delivery was designed and synthesized in order to effectively deliver ibuprofen to brain. Ibuprofen could be released from the prepared prodrugs when incubated with various buffers, mice plasma and brain homogenate. Also, the prodrug showed superior neuroprotective effect <i>in vitro</i> and <i>in vivo</i> than ibuprofen. Our results suggest that chemical modification of therapeutics with warheads of glucose and Vc represents a promising and efficient strategy for the development of brain-targeting prodrugs by utilizing the endogenous transportation mechanism of the warheads.</p

Real-Time Metabolomics on Living Microorganisms Using Ambient Electrospray Ionization Flow-Probe

Microorganisms such as bacteria and fungi produce a variety of specialized metabolites that are invaluable for agriculture, biological research, and drug discovery. However, the screening of microbial metabolic output is usually a time-intensive task. Here, we utilize a liquid microjunction surface sampling probe for electrospray ionization-mass spectrometry to extract and ionize metabolite mixtures directly from living microbial colonies grown on soft nutrient agar in Petri-dishes without any sample pretreatment. To demonstrate the robustness of the method, this technique was applied to observe the metabolic output of more than 30 microorganisms, including yeast, filamentous fungi, pathogens, and marine-derived bacteria, that were collected worldwide. Diverse natural products produced from different microbes, including Streptomyces coelicolor, Bacillus subtilis, and Pseudomonas aeruginosa are further characterized

Real-Time Metabolomics on Living Microorganisms Using Ambient Electrospray Ionization Flow-Probe

Microorganisms such as bacteria and fungi produce a variety of specialized metabolites that are invaluable for agriculture, biological research, and drug discovery. However, the screening of microbial metabolic output is usually a time-intensive task. Here, we utilize a liquid microjunction surface sampling probe for electrospray ionization-mass spectrometry to extract and ionize metabolite mixtures directly from living microbial colonies grown on soft nutrient agar in Petri-dishes without any sample pretreatment. To demonstrate the robustness of the method, this technique was applied to observe the metabolic output of more than 30 microorganisms, including yeast, filamentous fungi, pathogens, and marine-derived bacteria, that were collected worldwide. Diverse natural products produced from different microbes, including Streptomyces coelicolor, Bacillus subtilis, and Pseudomonas aeruginosa are further characterized

The Discovery of <i>N</i>‑(1-Methyl-5-(trifluoromethyl)‑1<i>H</i>‑pyrazol-3-yl)-5-((6- ((methylamino)methyl)pyrimidin-4-yl)oxy)‑1<i>H</i>‑indole-1-carboxamide (Acrizanib), a VEGFR‑2 Inhibitor Specifically Designed for Topical Ocular Delivery, as a Therapy for Neovascular Age-Related Macular Degeneration

A noninvasive topical ocular therapy for the treatment of neovascular or “wet” age-related macular degeneration would provide a patient administered alternative to the current standard of care, which requires physician administered intravitreal injections. This manuscript describes a novel strategy for the use of in vivo models of choroidal neovascularization (CNV) as the primary means of developing SAR related to efficacy from topical administration. Ultimately, this effort led to the discovery of acrizanib (LHA510), a small-molecule VEGFR-2 inhibitor with potency and efficacy in rodent CNV models, limited systemic exposure after topical ocular administration, multiple formulation options, and an acceptable rabbit ocular PK profile