A high precision method for length-based separation of carbon nanotubes using bio-conjugation, SDS-PAGE and silver staining

Enzyme-functionalized hydrogel film for extracorporeal uric acid reduction

Enzyme replacement therapy for hyperuricemia treatment has been proven effective for critical state hyperuricemia patients. Still, direct administration of recombinant uricase can induce several fatal side effects. To circumvent this drawback, hydrogel protein carriers can be used in platforms for extracorporeal treatment such as microscale-based devices. In this work, calcium alginate and poly-(vinyl alcohol) hydrogel films were studied for their urate oxidase immobilization and uric acid reduction, which could be implemented in microscale-based extracorporeal devices. A mathematical model was developed in conjunction with uric acid reduction experiments to evaluate the influence of mass transfer and reaction parameters in the Michaelis-Menten kinetic expression. Alginate hydrogels prepared with crosslinker 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-(hydroxysuccinimide) offered superior diffusivity of uric acid in the gel matrix at the maximum value ofD g , UA ≈ $$ {D}_{\mathrm{g},\mathrm{UA}}\approx $$ 1.98 × 10-11  m2 /s compared with alginate prepared solely from ionic crosslinking withD g , UA ≈ $$ {D}_{\mathrm{g},\mathrm{UA}}\approx $$  5.31 × 10-12  m2 /s at the same alginate concentration. The maximum value of νmax was experimentally determined at 7.78 × 10-5  mol/(m3 s). A 3% sodium alginate hydrogel with crosslinkers yielded the highest reduction of uric acid at 92.70%. The mathematical model demonstrated an excellent prediction of uric acid conversion suggesting potential use of the model for formulation and maximizing the therapeutic performance of functionalized hydrogels.

Elucidating the Molecular Interactions between Lipids and Lysozyme: Evaporation Resistance and Bacterial Barriers for Dry Eye Disease

Dry eye disease (DED) is a chronic condition characterized by ocular dryness and inflammation. The tear film lipid layer (TFLL) is the outermost layer composed of lipids and proteins that protect the ocular surface. However, environmental contaminants can disrupt its structure, potentially leading to DED. Although the importance of tear proteins in the TFLL functionality has been clinically recognized, the molecular mechanisms underlying TFLL-protein interactions remain unclear. In this study, we investigated tear protein-lipid interactions and analyzed their role in the TFLL functionality. The results show that lysozyme (LYZ) increases the stability of the TFLL by reducing its surface tension and increasing its surface pressure, resulting in increased TFLL evaporation and bacterial invasion resistance, with improved wettability and lubrication performance. These findings highlight the critical role of LYZ in maintaining ocular health and provide potential avenues for investigating novel approaches to DED treatment and patient well-being.

Genetic diversity of Venturia inaequalis isolates from the scabs in apple trees in Gansu Province, China, using AFLP markers

Apple scab is a serious disease that restricts the growth of cultivated apples. The objective of this study is to investigate the genetic variations and genetic structure of Venturia inaequalis in Gansu Province, China. 108 isolates of the pathogen V. inaequalis from the Jingning, Lingtai, Jingchuan, Xifeng, Ning and Maiji regions were collected, and their genetic diversity was analyzed using AFLP molecular marker technique. The results showed that genetic diversity was present among the isolates but was not statistically significant. Genetic distance values ranged from 0.0095 to 0.0762. Cluster analysis results showed that the 108 isolates could be divided into two clusters using a similarity coefficient of 0.69. A total of 104 isolates were contained in cluster I while four isolates were contained in Cluster II. From the AMOVA analysis, 98% of variations were observed within the same region, while 2% were observed across different regions. The analysis of population structure showed that 108 isolates had two common ancestors, with the Jingning isolates mainly being derived from the red ancestor. PCoA analysis showed that the Jingning isolates were independent to a certain extent. The different geographical location caused the genetic difference of the isolates. The genetic diversity of apple scab in Gansu Province is greatly aided by this work, which also offers a theoretical foundation for the use of molecular markers in assisted breeding to create novel resistant types.

A Novel Method for Carbon Nanotube Functionalization Using Immobilized Candida antarctica Lipase

Carbon nanotubes (CNTs) have been proposed as nanovehicles for drug or antigen delivery since they can be functionalized with different biomolecules. For this purpose, different types of molecules have been chemically bonded to CNTs; however, this method has low efficiency and generates solvent waste. Candida antarctica lipase is an enzyme that, in an organic solvent, can bind a carboxylic to a hydroxyl group by esterase activity. The objective of this work was to functionalize purified CNTs with insulin as a protein model using an immobilized lipase of Candida antarctica to develop a sustainable functionalization method with high protein attachment. The functionalized CNTs were characterized by scanning electron microscope (SEM), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzymatic functionalization of insulin on the surface of the CNTs was found to have an efficiency of 21%, which is higher in conversion and greener than previously reported by the diimide-activated amidation method. These results suggest that enzymatic esterification is a convenient and efficient method for CNT functionalization with proteins. Moreover, this functionalization method can be used to enhance the cellular-specific release of proteins by lysosomal esterases.

Surface Modification of Curcumin Microemulsions by Coupling of KLVFF Peptide: A Prototype for Targeted Bifunctional Microemulsions

Curcumin is one of the most promising natural therapeutics for use against Alzheimer's disease. The major limitations of curcumin are its low oral bioavailability and difficulty in permeating the blood-brain barrier. Therefore, designing a delivery system of curcumin to overcome its limitations must be employed. KLVFF, a peptide known as an amyloid blocker, was used in this study as a targeting moiety to develop a targeted drug delivery system. A prototype of transnasal KLVFF conjugated microemulsions containing curcumin (KLVFF-Cur-ME) for the nose-to-brain delivery was fabricated. The KLVFF-Cur-ME was developed by a titration method. A conjugation of KLVFF was performed through a carbodiimide reaction, and the conjugation efficiency was confirmed by FTIR and DSC technique. KLVFD-Cur-ME was characterized for the drug content, globule size, zeta potential, and pH. A transparent and homogeneous KLVFF-Cur-ME is achieved with a drug content of 80.25% and a globule size of 76.1 ± 2.5 nm. The pH of KLVFF-Cur-ME is 5.33 ± 0.02, indicating non-irritation to nasal tissues. KLVFD-Cur-ME does not show nasal ciliotoxicity. An ex vivo diffusion study revealed that KLVFF-Cur-ME partitions the porcine nasal mucosa through diffusion, following the Higuchi model. This investigation demonstrates the successful synthesis of a bifunctional KLVFF-Cur-ME as a novel prototype to deliver anti-Aβ aggregation via an intranasal administration.

Advances and Perspectives in the Use of Carbon Nanotubes in Vaccine Development

Advances in nanobiotechnology have allowed the utilization of nanotechnology through nanovaccines. Nanovaccines are powerful tools for enhancing the immunogenicity of a specific antigen and exhibit advantages over other adjuvant approaches, with features such as expanded stability, prolonged release, decreased immunotoxicity, and immunogenic selectivity. We introduce recent advances in carbon nanotubes (CNTs) to induce either a carrier effect as a nanoplatform or an immunostimulatory effect. Several studies of CNT-based nanovaccines revealed that due to the ability of CNTs to carry immunogenic molecules, they can act as nonclassical vaccines, a quality not possessed by vaccines with traditional formulations. Therefore, adapting and modifying the physicochemical properties of CNTs for use in vaccines may additionally enhance their efficacy in inducing a T cell-based immune response. Accordingly, the purpose of this study is to renew and awaken interest in and knowledge of the safe use of CNTs as adjuvants and carriers in vaccines.

In situ photocrosslinkable formulation of nanocomposites based on multi-walled carbon nanotubes and formononetin for potential application in spinal cord injury treatment

Carbon nanotubes (CN) have been studied to treat spinal cord injuries because of its electrical properties and nanometric dimensions. This work aims to develop a photopolymerizable hydrogel containing CN functionalized with an anti-inflammatory molecule to be used in situ on spinal cord injuries. The CN functionalization step was done using the drug (formononetin). The nanocomposites were characterized by morphological analysis, FTIR, Raman Spectroscopy, thermal analysis and cytotoxicity assays (MTT and HET-CAM). The nanocomposites were incorporated into gelatin methacryloyl hydrogel and exposed to UV light for photopolymerization. The volume of the formulation and the UV exposition time were also analyzed. The CN characterization showed that formononetin acted as a functionalization agent. The functionalized CN showed safe characteristics and can be incorporated in photocrosslinkable formulation. The UV exposition time for the formulation photopolymerization was compatible with the cell viability and also occurred in the injury site.

Construction of RNA nanotubes

Nanotubes are miniature materials with significant potential applications in nanotechnological, medical, biological and material sciences. The quest for manufacturing methods of nano-mechanical modules is in progress. For example, the application of carbon nanotubes has been extensively investigated due to the precise width control, but the precise length control remains challenging. Here we report two approaches for the one-pot self-assembly of RNA nanotubes. For the first approach, six RNA strands were used to assemble the nanotube by forming a 11 nm long hollow channel with the inner diameter of 1.7 nm and the outside diameter of 6.3 nm. For the second approach, six RNA strands were designed to hybridize with their neighboring strands by complementary base pairing and formed a nanotube with a six-helix hollow channel similar to the nanotube assembled by the first approach. The fabricated RNA nanotubes were characterized by gel electrophoresis and atomic force microscopy (AFM), confirming the formation of nanotube-shaped RNA nanostructures. Cholesterol molecules were introduced into RNA nanotubes to facilitate their incorporation into lipid bilayer. Incubation of RNA nanotube complex with the free-standing lipid bilayer membrane under applied voltage led to discrete current signatures. Addition of peptides into the sensing chamber revealed discrete steps of current blockage. Polyarginine peptides with different lengths can be detected by current signatures, suggesting that the RNA-cholesterol complex holds the promise of achieving single molecule sensing of peptides.

A high precision length-based carbon nanotube ladder

Today, carbon nanotubes manufacturers as well as users such as molecular electronics, nanomedicine, nano-biotechnology and similar industries are facing a major challenge: lack of length uniformity of carbon nanotubes in mass production. An effective solution to this major issue is the use of a length-based ladder. We are, for the first time, presenting such a valuable tool to determine the length purity. Our length-based carbon nanotubes ladder, containing a series of carbon nanotubes markers with different lengths, is made based on three combined techniques - bio-conjugation, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and silver staining. Creating an indicator using conjugation of a biomolecule with carbon nanotubes to make a carbon nanotubes ladder is a novel idea and a significant step forward for length-based carbon nanotubes separation. The very sensitive silver staining technique allows a precise visualization and quantification of the gel. This ladder with a pending patent by Northeastern University is an effective quality control tool when bulk quantities of nanotubes with a desirable length are manufactured.