Characterization and physical-chemistry of methoxypoly(ethylene glycol)-g-chitosan

Facchinatto, William Marcondes; Fiamingo, Anderson; Santos, Danilo Martins dos; Filho, Sérgio Paulo Campana

doi:10.1016/j.ijbiomac.2018.11.246

Cited by 23 publications

(13 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…10-fold) increase in viscosity for the pH 4 and 5.8 mucin solutions. For these solutions, the concentration of H + ions is low enough that the addition of Ca 2+ causes more intermolecular associative interactions resulting in a higher dynamic viscosity and less pronounced slope 45 . For the pH 2.1 mucin solution, only a slight viscosity increase is observed with Ca 2+ addition at lower shear rates.…”

Section: Mucin Rheological Behavior and Microstructure As A Function mentioning

confidence: 99%

Chemical and Microstructural Characterization of pH and [Ca2+] Dependent Sol-Gel Transitions in Mucin Biopolymer

Curnutt

Smith

Darrow

et al. 2020

Sci Rep

View full text Add to dashboard Cite

Mucus is responsible for controlling transport and barrier function in biological systems, and its properties can be significantly affected by compositional and environmental changes. In this study, the impacts of pH and cacl 2 were examined on the solution-to-gel transition of mucin, the primary structural component of mucus. Microscale structural changes were correlated with macroscale viscoelastic behavior as a function of pH and calcium addition using rheology, dynamic light scattering, zeta potential, surface tension, and ftiR spectroscopic characterization. Mucin solutions transitioned from solution to gel behavior between pH 4-5 and correspondingly displayed a more than tenfold increase in viscoelastic moduli. Addition of CaCl 2 increased the sol-gel transition pH value to ca. 6, with a twofold increase in loss moduli at low frequencies and tenfold increase in storage modulus. changing the ionic conditions-specifically [H + ] and [ca 2+ ]-modulated the sol-gel transition pH, isoelectric point, and viscoelastic properties due to reversible conformational changes with mucin forming a network structure via non-covalent cross-links between mucin chains. Mucin is a polyelectrolyte glycoprotein found in mucus, the structured complex fluid found in all types of organisms from bacteria to humans. In vertebrates, mucus is produced by mucus membranes and can be found lining the eyelids, mouth, and nose, as well as gastrointestinal, respiratory, and genital tracts. Since the 1970s 1 , animal mucus and mucin solutions have been well studied, especially the roles mucus plays in drug delivery 2-6 , disorders like cystic fibrosis 7,8 , and its protective biological functions 9-12. Mucin glycoproteins are present in mucus at concentrations of 1-5%, along with electrolytes (ca. 1%), lipids (1-2%), other proteins (1-2%), and water (90-95%) 13. Despite being present in low concentrations, mucin glycoproteins are primarily responsible for the protective and lubricative functions of mucus within the body. Solubilized mucin behaves as a complex fluid with changing viscoelastic and structural properties in response to its environmental conditions. Mucin glycoproteins are responsible for the majority of the physical properties of mucus, as mucin conformation, intra-and inter-strand bonding, and microstructure changes in response to environmental factors such as pH 6,7,12,14 , temperature 2,15 , and ion content 1,14,16. All these factors affect the reversible supramolecular bonding between functional groups within the protein strands, which modifies the microstructure as well as the mechanical and transport properties of the mucin network. In aqueous solutions, biopolymers like mucin form networks that can change dynamically due to non-covalent crosslinks, including physical entanglements and supramolecular bonding. Mucins resemble a bottle brush polymer with a protein backbone and oligosaccharide (carbohydrate) side chains arranged radially from the backbone. The protein backbone of the mucin biopolymer has areas that are dense w...

show abstract

Section: Mucin Rheological Behavior and Microstructure As A Function mentioning

confidence: 99%

Chemical and Microstructural Characterization of pH and [Ca2+] Dependent Sol-Gel Transitions in Mucin Biopolymer

Curnutt

Smith

Darrow

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…A execução de modificações químicas, principalmente nos grupos hidroxila e amino das unidades estruturais de quitosana, permite a preparação de derivados com diferentes características, propriedades e atividades, a depender das rotas reacionais e reagentes empregados. Dispondo de vasta gama de reagentes e rotas reacionais, é possível preparar derivados de quitosana com natureza hidrofóbica, 42 hidrofílica, 43 anfifílica, 44 aniônica, 45 catiônica 32 e anfotérica. 46 As reações de derivatização de quitosana almejam conferir novas propriedades físico-químicas, como solubilidade em ampla faixa de pH e capacidade de micelização, ou potencializar atividades preexistentes, inclusive atividade antimicrobiana.…”

Section: Quitina E Quitosanaunclassified

“…46 As reações de derivatização de quitosana almejam conferir novas propriedades físico-químicas, como solubilidade em ampla faixa de pH e capacidade de micelização, ou potencializar atividades preexistentes, inclusive atividade antimicrobiana. 38 Assim, por exemplo, os derivados de quitosana resultantes de reações com cloreto de glicidiltrimetilamônio 32 e poli(etilenoglicol), 43 são hidrossolúveis em ampla faixa de pH (2 < pH < 11), enquanto a reação de quitosana com cloreto de palmitoíla resulta em derivado hidrofóbico que forma micelas nas condições adequadas. 43 Os derivados de quitosana vêm sendo amplamente explorados visando à preparação de materiais nanoestrurados com elevado potencial para aplicações como carreadores de fármacos, 43,47 curativos para lesões de pele 32 e géis termorreversíveis para aplicações tópicas.…”

Section: Quitina E Quitosanaunclassified

See 1 more Smart Citation

Biopolímeros, Processamento e Aplicações

Habitzreuter¹,

Gabriel²,

Semensato³

et al. 2022

Nanotecnologia Aplicada a Polímeros

View full text Add to dashboard Cite

Os biopolímeros constituem uma importante classe de polímeros que atrai crescente atenção e interesse tanto de pesquisadores quanto de indústrias. Em contraste com polímeros sintéticos, que são produzidos a partir de derivados de petróleo, portanto de fontes não renováveis, os biopolímeros são produzidos por organismos vivos, como plantas, animais e fungos, via processos metabólicos intracelulares complexos que envolvem reações catalisadas por enzimas e reações de polimerização. 1 É importante destacar que alguns autores incluem, nessa categoria, polímeros sintetizados a partir de matérias-primas de origem natural, 2 como poli(acetato de vinila) (PVA), poli(ácido lático) (PLA) e polietileno, desde que produzido a partir de bioetanol, e também podem incluir aqueles que são biodegradáveis. No entanto, no desenvolvi-

show abstract

“…However, there are important limitations to the potential chitosan applications in the biomedical field, especially its limited solubility in neutral and alkaline media. Attempts to circumvent this difficulty include chemical modification with functional groups via carboxymethylation, quaternization, PEGylation, among other possibilities (Facchinatto, Fiamingo, dos Santos, & Campana-Filho, 2019;Jia, Shen, & Xu, 2001;Rinaudo, 2006;Roberts, 1992, Fiamingo et al 2017. Unfortunately, many of these procedures decrease the polycationic character of chitosan and increase its cytotoxicity (Jintapattanakit, Mao, Kissel, & Junyaprasert, 2008;Tan, Ma, Lin, Liu, & Tang, 2013).…”

Section: Introductionmentioning

confidence: 99%

Tuning the Properties of High Molecular Weight Chitosans to Develop Full Water Solubility Within a Wide pH Range

Fiamingo

Filho²,

Oliveira³

2020

Preprint

Self Cite

View full text Add to dashboard Cite

The preparation of chitosans soluble in physiological conditions has been sought for years, but so far solubility in non-acidic aqueous media has only been achieved at the expense of lowering chitosan molecular weight. In this work, we applied the multistep ultrasound-assisted deacetylation process (USAD process) to β-chitin and obtained extensively deacetylated chitosans with high molecular weights (Mw ≥ 1,000,000 g mol-1). The homogeneous N-acetylation of a chitosan sample resulting from three consecutive USAD procedures allowed us to produce chitosans with a high weight average degree of polymerization (DPw ≈ 6,000) and tunable degrees of acetylation (DA from 5 to 80%). N-acetylation was carried out under mild conditions to minimize depolymerization, while preserving a predominantly random distribution of 2-amino-2-deoxy-D-glucopyanose (GlcN) and 2-acetamido-2-deoxy-D-glucopyanose (GlcNAc) units. This close to random distribution, inferred with deconvolution of nuclear magnetic resonance (1H NMR) spectra, is considered as responsible for the solubility within a wide pH range. Two of the highly N-acetylated chitosans (DA ≈ 60 % and ≈ 70 %) exhibited full water solubility even at neutral pH, which can expand the biomedical applications of chitosans.

show abstract

Characterization and physical-chemistry of methoxypoly(ethylene glycol)-g-chitosan

Cited by 23 publications

References 41 publications

Chemical and Microstructural Characterization of pH and [Ca2+] Dependent Sol-Gel Transitions in Mucin Biopolymer

Chemical and Microstructural Characterization of pH and [Ca2+] Dependent Sol-Gel Transitions in Mucin Biopolymer

Biopolímeros, Processamento e Aplicações

Tuning the Properties of High Molecular Weight Chitosans to Develop Full Water Solubility Within a Wide pH Range

Contact Info

Product

Resources

About