Biotin-Conjugated Cellulose Nanofibers Prepared via Copper-Catalyzed Alkyne-Azide Cycloaddition (CuAAC) “Click” Chemistry

Abstract

As potential high surface area for selective capture in diagnostic or filtration devices, biotin-cellulose nanofiber membranes were fabricated to demonstrate the potential for specific and bio-orthogonal attachment of biomolecules onto nanofiber surfaces. Cellulose acetate was electrospun and substituted with alkyne groups in either a one- or two-step process. The alkyne reaction, confirmed by FTIR and Raman spectroscopy, was dependent on solvent ratio, time, and temperature. The two-step process maximized alkyne substitution in 10/90 volume per volume ratio (v/v) water to isopropanol at 50 °C after 6 h compared to the one-step process in 80/20 (v/v) at 50 °C after 48 h. Azide-biotin conjugate “clicked” with the alkyne-cellulose via copper-catalyzed alkyne-azide cycloaddition (CuAAC). The biotin-cellulose membranes, characterized by FTIR, SEM, Energy Dispersive X-ray spectroscopy (EDX), and XPS, were used in proof-of-concept assays (HABA (4′-hydroxyazobenzene-2-carboxylic acid) colorimetric assay and fluorescently tagged streptavidin assay) where streptavidin selectively bound to the pendant biotin. The click reaction was specific to alkyne-azide coupling and dependent on pH, ratio of ascorbic acid to copper sulfate, and time. Copper (II) reduction to copper (I) was successful without ascorbic acid, increasing the viability of the click conjugation with biomolecules. The surface-available biotin was dependent on storage medium and time: Decreasing with immersion in water and increasing with storage in air.

Targeting Multidrug Resistance With Antimicrobial Peptide-Decorated Nanoparticles and Polymers

“…Alternatively, the conjugate can be produced in solution using the free peptide if chemo-selective coupling methods is used. The later exploits the activation by thiol-reactive maleimide groups, or amino reactive N -hydroxysuccinimides (NHS), on top of procedure, such as copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC), among others ( Goodge and Frey, 2020 ; Huan et al, 2020 ).…”

Lignocellulosic–biomolecules conjugated systems: green-engineered complexes modified by covalent linkers

“…They encompass several heteroatom bonds and exhibit high thermodynamical forces, with copper-catalyzed azidealkynes being the most notable. 76,77 In a cellulose biconjugated system, P-toluenesulfonyl chloride (TsCl)/triethylamine modify cellulose to facilitate azide functionalization (CNF-N 3 ), while tosylation and alkyne may functionalize biomolecules such as biotin and beta-cyclodextrin (b-CD) (an oligosaccharide). For instance, alkyne-functionalized b-CD and CNF-N 3 undergo a click chemistry reaction, forming a triazole bond in a hydroxide sodium (NaOH) medium (Fig.…”

Stimuli‐Mediated Specific Isolation of Exosomes from Blood Plasma for High‐Throughput Profiling of Cancer Biomarkers

“…Then, the mixture was heated up to 40 °C for 1 h to induce the precipitation of PNN-SA and excess PNN, resulting in the separation of free SA from PNN-SA. The free SA in the supernatants was measured by the 2-(4-hydroxyphenylazo)benzoic acid (HABA) assays, [35,36] by which the optimal ratio of SA to PNN was determined to be 1:10 (Figure S5a, Supporting Information). Based on the HABA assays, the reaction time for the preparation of PNN-SA was optimized to be 5 h (Figure S5b, Supporting Information).…”