Acid Dihydrazide Research Articles

Corrosion inhibition performance of azelaic acid dihydrazide: a molecular dynamics and Monte Carlo simulation study.

The adsorption of azelaic acid dihydrazide as an environmentally friendly mild steel corrosion inhibitor on the iron surface was modeled in this study. We used density functional theory (DFT) calculations and Monte Carlo (MC) and molecular dynamics (MD) simulations to illustrate the interactions engaged. The interaction of the azelaic acid derivatives with iron metal (Fe) was examined by DFT as a typical example of a corrosion prevention mechanism after the optimized molecular structures of these molecules were investigated. Structures, binding energies, Fikui's charge indicator, electron transfer, and chemical potential are all discussed. The presence of significant binding between the inhibitor and Fe metal is supported by analysis of the resultant complex. Then, in an acidic solution comprising 491 H2O, nine chlorine ion Cl-, and nine hydronium ion H3O+, molecular dynamics and Monte Carlo (MC) simulation were used to model the adsorption of azelaic acid dihydrazide on the iron Fe (110) surface. In addition, radial distribution function (RDF) and interaction energy (Ei) were evaluated in this work to further our understanding of interactions between azelaic acid dihydrazide and iron surfaces. Furthermore, we discovered that our inhibitors have an excellent ability to slow down the movement of corrosive particles in law temperature and thus to inhibit the metallic substrate against corrosive electrolyte, based on the temperature impact investigation. The result of density functional theory and Monte Carlo and molecular dynamics descriptors obtained were in good agreement with the experimental result.

Three-dimensional bioprinting of polysaccharide-based self-healing hydrogels with dual cross-linking.

Three-dimensional (3D) bioprinting technique is useful to fabricate constructs with functional and biological structures for various biomedical applications. Oxidized hyaluronate (OHA) and glycol chitosan (GC) can form autonomous self-healing hydrogels when adipic acid dihydrazide (ADH) is used. We demonstrate that hyaluronate-alginate hybrid (HAH) polymers can be used for secondary physical cross-linking of OHA/GC/ADH hydrogel with calcium ions after 3D printing. The molecular weight of hyaluronate can be varied while keeping the molecular weight of alginate in HAH. The mechanical stiffness and stability of gels after 3D printing are strongly dependent on the molecular weight of HAH at the same cross-linking density. In vitro chondrogenic differentiation of ATDC5 cells encapsulated in 3D-printed constructs is dependent on the molecular weight of HAH in gels. This dual cross-linking system consisting of naturally occurring biocompatible polysaccharides may have potential in the 3D bioprinting of custom-made scaffolds for tissue engineering applications.

Highly efficient and selective adsorption of heavy metal ions by hydrazide-modified sodium alginate

In the present study, a new potential adsorbent for the separation and removal of heavy metal ions was prepared using hydrazide modification. Characterization of structural and chemical properties of the absorbent indicated the dialdehyde sodium alginate (DSA) grafted adipic acid dihydrazide (AAD) plays a crucial role. The adsorption process correlated well with Freundlich isotherm and pseudo-second-order kinetics models. Additionally, the adsorption capacities for Hg2+, Pb2+, Cd2+, and Cu2+ were 7.833, 2.036, 4.766, and 3.937 mmol g−1, respectively. The thermodynamic parameter for the sorption demonstrated the process is endothermic and spontaneous. FT-IR and XPS analysis revealed the combination of chelation interactions and ion exchange between nitrogen, oxygen atoms and heavy metal ions. Moreover, after 10 times adsorption–desorption recycles, the adsorption efficiency of the adsorbent was slightly decreased. In conclusion, the as-prepared adsorbent has great potential in practical water pollution purification.

Antibacterial Hydrogel with Self-Healing Property for Wound-Healing Applications.

Hydrogels with inherent antibacterial ability are a focus in soft tissue repair. Herein, a series of antibacterial hydrogels were fabricated by quaternized N-[3-(dimethylamino)propyl] methacrylamide (quaternized P(DMAPMA-DMA-DAA)) bearing copolymers with dithiodipropionic acid dihydrazide (DTDPH) as cross-linker. The hydrogels presented efficient self-healing capability as well as a pH and redox-triggered gel-sol-gel transition property that is based on the dynamic acylhydrazone bond and disulfide linkage. Furthermore, the hydrogels showed good antibacterial activity, biocompatibility, degradability, and sustained release ability. More importantly, the in vivo experiments demonstrated that the hydrogels loaded with mouse epidermal growth factor (mEGF) significantly accelerated wound closure by preventing bacterial infection and promoting cutaneous regeneration in the wound model. The antibacterial hydrogels with self-healing behavior hold great potential in wound treatment.

TEMPO/TCC as a Chemo Selective Alternative for the Oxidation of Hyaluronic Acid.

Hyaluronic acid (HA)-based hydrogels are very commonly applied as cell carriers for different approaches in regenerative medicine. HA itself is a well-studied biomolecule that originates from the physiological extracellular matrix (ECM) of mammalians and, due to its acidic polysaccharide structure, offers many different possibilities for suitable chemical modifications which are necessary to control, for example, network formation. Most of these chemical modifications are performed using the free acid function of the polymer and, additionally, lead to an undesirable breakdown of the biopolymer’s backbone. An alternative modification of the vicinal diol of the glucuronic acid is oxidation with sodium periodate to generate dialdehydes via a ring opening mechanism that can subsequently be further modified or crosslinked via Schiff base chemistry. Since this oxidation causes a structural destruction of the polysaccharide backbone, it was our intention to study a novel synthesis protocol frequently applied to selectively oxidize the C6 hydroxyl group of saccharides. On the basis of this TEMPO/TCC oxidation, we studied an alternative hydrogel platform based on oxidized HA crosslinked using adipic acid dihydrazide as the crosslinker.

Chemical Speciation study of Ternary complexes of Zn(II)-Azelaic acid dihydrazide-L-Proline and Zn(II)-Azelaic acid dihydrazide-L-Lysine in aqueous medium

Chemometric speciation study of ternary complexes containing Zn(II) with a non toxic and ditopic ligand L= Azelaic acid dihydrazide (AZDH) and X= α-amino acids (L - Proline and L – Lysine) of type [MmLlX xHh], (where m=1, 2; l=1; x=1, 2 and h= -2 to 5) in different ratios of M:L:X= 1:1:1, 1:2:1, 2:1:1and 2:1:2 was carried out using potentiometric method of data acquisition followed by chemometric modelling methods of analysis using SOPHD program and MINIQUAD-75 program. The stability constants of the ternary complexes were determined at 303± 0.1 K and 0.1M ionic strength. Best-fit chemical models were selected on the basis of statistical parameters like standard deviation (SD), U (sum of the residual squares in mass balance equations) and chi-square test etc. Zn(II)-AZDHLysine ternary complexes were found to be more stable due to side chain presence in the lysine. Comparitive stabilities of ternary complexes and binary species were evaluated quantitatively using  log K formulation.

Injectable Hydrogel Based on Modified Gelatin and Sodium Alginate for Soft-Tissue Adhesive.

To assist or replace the traditional suture techniques for wound closure, soft-tissue adhesives with excellent adhesion strength and favorable biocompatibility are of great significance in biomedical applications. In this study, an injectable hydrogel tissue adhesive containing adipic acid dihydrazide–modified gelatin (Gel-ADH) and oxidized sodium alginate (OSA) was developed. It was found that this tissue adhesive possessed a uniform structure, appropriate swelling ratio, good injectability, and excellent hemocompatibility and cytocompatibility. The adhesion capacity of the developed adhesive with optimized component and concentration was stronger than that of the commercial adhesive Porcine Fibrin Sealant Kit. All these results suggested that the developed hydrogel was a promising candidate for a soft-tissue adhesive.

Development of a new peptide-bead coupling method for an all peptide–based Luminex multiplexing assay for detection of Plasmodium falciparum antibody responses

Using a recombinant protein antigen for antibody testing shows a sum of antibody responses to multiple different immune epitopes existing in the protein antigen. In contrast, the antibody testing to an immunogenic peptide epitope reflects a singular antibody response to the individual peptide epitope. Therefore, using a panel of peptide epitopes provides an advantage for profiling multiple singular antibody responses with potential to estimate recent malaria exposure in human infections. However, transitioning from malaria immune epitope peptide-based ELISA to an all peptide bead-based multiplex Luminex assay presents some challenges including variation in the ability of different peptides to bind beads. The aim of this study was to develop a peptide coupling method while demonstrating the utility of these peptide epitopes from multiple stage antigens of Plasmodium falciparum for measuring antibodies.Successful coupling of peptide epitopes to beads followed three steps: 1) development of a peptide tag appended to the C-terminus of each peptide epitope consisting of beta-alanine–lysine (x 4)--cysteine, 2) bead modification with a high concentration of adipic acid dihydrazide, and 3) use of the peptide epitope as a blocker in place of the traditional choice, bovine serum albumin (BSA). This new method was used to couple 12 peptide epitopes from multiple stage specific antigens of P. falciparum, 1 Anopheles mosquito salivary gland peptide, and 1 Epstein-Barr virus peptide as an assay control. The new method was applied to testing of IgG in pooled samples from 30 individuals with previously repeated malaria exposure in western Kenya and IgM and IgG in samples from 37 U.S. travelers with recent exposure to malaria.The new peptide-bead coupling method and subsequent multiplex Luminex assay showed reliable detection of IgG to all 14 peptides in Kenyan samples. Among 37 samples from U.S. travelers recently diagnosed with malaria, IgM and IgG to the peptide epitopes were detected with high sensitivity and variation. Overall, the U.S. travelers had a much lower positivity rates of IgM than IgG to different peptide epitopes, ranging from a high of 62.2% positive for one epitope to a low of only 5.4% positive for another epitope. In contrast, the travelers had IgG positive rates from 97.3% to 91.9% to various peptide epitopes. Based on the different distribution in IgM and IgG positivity to overall number of peptide epitopes and to the number of pre-erythrocytic, erythrocytic, gametocytic, and salivary stage epitopes at the individual level, four distinct patterns of IgM and IgG responses among the 37 samples from US travelers were observed. Independent peptide-bead coupling and antibody level readout between two different instruments also showed comparable results.Overall, this new coupling method resolves the peptide-bead coupling challenge, is reproducible, and can be applied to any other immunogenic peptide epitopes. The resulting all peptide bead-based multiplex Luminex assay can be expanded to include other peptide epitopes of P. falciparum, different malaria species, or other diseases for surveillance, either in US travelers or endemic areas.

3D Printing of Polysaccharide-Based Self-Healing Hydrogel Reinforced with Alginate for Secondary Cross-Linking.

Three-dimensional (3D) bioprinting has been attractive for tissue and organ regeneration with the possibility of constructing biologically functional structures useful in many biomedical applications. Autonomous healing of hydrogels composed of oxidized hyaluronate (OHA), glycol chitosan (GC), and adipic acid dihydrazide (ADH) was achieved after damage. Interestingly, the addition of alginate (ALG) to the OHA/GC/ADH self-healing hydrogels was useful for the dual cross-linking system, which enhanced the structural stability of the gels without the loss of their self-healing capability. Various characteristics of OHA/GC/ADH/ALG hydrogels, including viscoelastic properties, cytotoxicity, and 3D printability, were investigated. Additionally, potential applications of 3D bioprinting of OHA/GC/ADH/ALG hydrogels for cartilage regeneration were investigated in vitro. This hydrogel system may have potential for bioprinting of a custom-made scaffold in various tissue engineering applications.

3D Printing of dynamic tissue scaffold by combining self-healing hydrogel and self-healing ferrogel

Hydrogels have been widely utilized in tissue engineering applications as functional and biological synthetic extracellular matrices (ECMs) can be created with gels. However, typical hydrogels cannot be exploited in 3D printing, especially in extrusion printing, unless post-cross-linking after printing is provided. Additionally, dynamic tissue scaffolds that can mimic ECM environments in the body have been demonstrated to be useful in tissue engineering. Here, we hypothesized that a 3D-printed dynamic tissue scaffold could be fabricated by combining self-healing hydrogel and self-healing ferrogel without post-cross-linking, which could be useful for the regulation of cell phenotype under magnetic stimulation. Hydrogels were formed from oxidized sodium hyaluronate and glycol chitosan, and adipic acid dihydrazide was additionally utilized for self-healing behavior of the gel. Superparamagnetic iron oxide nanoparticles (SPIONs) were also used to prepare a magnetically responsive hydrogel system (i.e., ferrogel). Physicochemical properties, cytotoxicity, and printability of the self-healing hydrogel/ferrogel system fabricated by a 3D printing process, were investigated. Dimensional changes in a tissue scaffold were achieved by the application of a magnetic field. Interestingly, chondrogenic differentiation of ATDC5 cells cultured within the dynamic tissue scaffold was enhanced by applying a magnetic field in vitro. This approach may be useful for fabricating dynamic tissue scaffolds by a 3D printing method for tissue engineering applications.

PH-responsive hydrogel loaded with insulin as a bioactive dressing for enhancing diabetic wound healing

The healing of diabetic foot ulcers (DFUs) is a major challenge for clinical treatment because of the hyperglycemic and acidic microenvironment in the wound area. In this study, a self-healing, injectable, and pH-responsive hydrogel was synthesized by N-carboxyethyl chitosan (N-chitosan), hyaluronic acid–aldehyde (HA-ALD), adipic acid dihydrazide (ADH) through the formation of the reversible dynamic bonds, acylhydrazone and imine bonds. The presence of the acylhydrazone bond characterizes the hydrogel pH-responsive property. In this study, the insulin glargine was successfully incorporated into the hydrogel, allowing its sustained and pH-responsive releasing from the hydrogel for up to 14 days. The hydrogel presented good compatibility and pore structure, and the insulin released from the hydrogel maintained its original bioactivity. Full thickness wounds were established on the feet of diabetic rats to evaluate the therapeutic effect of the dressing. The results revealed that the bioactive insulin-loaded hydrogel dressing shortened the inflammatory phase, enhanced granulation tissue formation, promoted collagen deposition, accelerated re-epithelialization and neovascularization, and postponed or even improved peripheral neuropathy, thus, significantly accelerated DFUs healing. Our findings showed that the insulin-loaded hydrogels had promising potential as a multifunctional bioactive wound dressing for enhancing DFUs healing.

Potentiometric determination of stability constants of ternary complexes of first row transition metal ions with ditopic azelaic acid dihydrazide and aspartic acid in aqueous medium

A Chemical speciation study of ternary complexes containing transition metal ions (Mn2+,Co2+,Ni2+, Cu2+ and Zn2+) with a ditopic novel ligand L ​= ​Azelaic acid dihydrazide (AZDH) and X ​= ​l-Aspartic acid of type [MmLlX xHh], (where m ​= ​1, 2; l ​= ​1; x ​= ​1, 2 and h ​= ​−2 to 5) in different ratios of M:L:X ​= ​1:1:1, 1:2:1, 2:1:1and 2:1:2 was carried out using pH -potentiometric method of data acquisition and applied to chemometric modelling methods of analysis. MINIQUAD-75 program was used for the resolution of the plausible species and their corresponding formation constants at 303 ​± ​0.1 ​K, and 0.01 ​M ionic strength. Species concentration distribution diagrams were generated using HySS program. Best-fit chemical models were selected on the basis of statistical parameters like Standard deviation (SD), U (sum of the squares of the residuals in mass balance equations), and chi-square test etc. Relatively stable ternary complexes were evaluated quantitatively using Δlog K formulation. All the formation constants for the species were compared for Irving-Williams order of stability.

A γ-PGA/KGM-based injectable hydrogel as immunoactive and antibacterial wound dressing for skin wound repair

Injectable hydrogels, of which the cover area and volume can be flexibly adjusted according to the shape and depth of the wound, are considered to be an ideal material for wound dressing. Konjac glucomannan (KGM) is a natural polysaccharide with immunomodulatory capability, while γ-polyglutamic acid (γ-PGA) is a single chain polyamino acid with moisturizing, water-retention and antibacterial properties. This work intended to combine the advantages of the two materials to prepare an injectable hydrogel (P-OK) by mixing the adipic acid dihydrazide (ADH) modified γ-PGA with oxidized KGM. The chemical structures, the physical and chemical properties, and the biological properties of the P-OK hydrogel were evaluated. The optimal conditions to form the P-OK hydrogel were fixed, and the cytotoxicity, qPCR, antibacterial and animal experiments were performed. Results showed that the P-OK hydrogel had a fast gelation time, good water-retention rate, little cytotoxicity, good immunomodulating and antibacterial capabilities, and could shorten the healing period in the rat full-thickness defect model, which makes it a potential candidate for wound repair dressing.

Scaffolds Designing from Protein-loadable Coaxial Electrospun Fibermats of poly(acrylamide)-Co-poly(diacetone acrylamide) and Gelatin

Background: Aiming at in situ regenerative therapy, the tailored design of cytokine-releasing scaffolds is still one of the crucial issues to be studied. A core-shell fibermat is one of the attractive platforms for this purpose. But, very few detail the importance of choosing the right material for the shell units that can endow efficient release properties. Objective: In this study, we characterized the effectiveness of core-shell fibermats that possess cross-linked gelatin (CLG) as the shell layer of constituent nanofibers, as a protein-releasing cell-incubation scaffold. Methods: For the core nanofibers in the core-shell fibermats, we utilized a crosslinked copolymer of poly(acrylamide)-co-poly(diacetone acrylamide) (poly(AM/DAAM)) and adipic acid dihydrazide (ADH), poly(AM/DAAM)/ADH. By coaxial electrospinning and the subsequent crosslinking of the gelatin layer, we successfully constructed core-shell fibermats consisting of double-layered nanofibers of poly(AM/DAAM)/ADH and CLG. Using fluorescein isothiocyanate-labeled lysozyme (FITC-Lys) as a dummy guest protein, we characterized the release behavior of the coreshell fibermats containing a CLG layer. Upon loading basic fibroblast growth factor (bFGF) as cargo in our fibermats, we also characterized impacts of the released bFGF on proliferation of the incubated cells thereon. Results: Although the single-layered poly(AM/DAAM)/ADH nanofiber fibermats did not adhere to the mammalian cells, the core-shell fibermat with the CLG shell layer exhibited good adherence and subsequent proliferation. A sustained release of the preloaded FITC-Lys over 24 days without any burst release was observed, and the cumulative amount of released protein reached over 65% after 24 days. Upon loading bFGF in our fibermats, we succeeded in promoting cell proliferation, and highlighting its potential for use in therapeutic applications. Conclusion: We successfully confirmed that core-shell fibermats with a CLG shell layer around the constituent nanofibers, were effective as protein-releasing cell-incubation scaffolds.

Photo- and Acid-Degradable Polyacylhydrazone-Doxorubicin Conjugates.

Light-mediated polymer degradation has attracted considerable attention in various applications, including photo-patterning, tissue engineering and photo-triggered drug delivery. In this study, we report the synthesis and characterization of a new, linear, main-chain photo- and acid-degradable copolymer based on acylhydrazone linkages. The polymer was synthesized via a step-growth copolymerization of adipic acid dihydrazide with a bifunctional poly(ethylene glycol) bearing benzaldehyde end-groups, under mild acidic conditions, to afford a hydrophilic PEG-alt-adipic acid (PEG-alt-AA) alternating copolymer. The synthesized polymer was characterized by size exclusion chromatography, proton nuclear magnetic resonance and attenuated total reflection-Fourier transform infrared spectroscopies. The main-chain photo- and acid-induced degradation of the copolymer in dimethylsulfoxide and water, respectively, was verified by UV-vis spectroscopy at light intensities as low as 0.1 mW cm−2 at λ = 254 nm. Next, a model anticancer drug, doxorubicin (DOX), was chemically linked to the polymer chain end(s) via acylhydrazone bond(s), resulting in amphiphilic PEG-alt-adipic acid-DOX (PEG-alt-AA-DOX) polymer–drug conjugates. The conjugates were self-assembled in water to form spherical nanoparticles, as evidenced by scanning and transmission electron microscopies. The irradiation of the self-assembled PEG-alt-AA-DOX conjugates with UV light and the decrease of the solution pH resulted in the disruption of the assemblies due to the photolysis and acidolysis of the acylhydrazone bonds, and the release of the therapeutic cargo.

Development of a pneumococcal conjugate vaccine based on chemical conjugation of polysaccharide serotype 6B to PspA

The use of conjugate vaccines remains an effective intervention to prevent pneumococcal diseases. In order to expand vaccine coverage, the inclusion of pneumococcal proteins as carriers is a propitious alternative that has been explored over the past few years. In this study, pneumococcal surface protein A (PspA) clade 1, family 1 (PspA1) and clade 3, family 2 (PspA3) were used as carrier proteins for pneumococcal capsular polysaccharide serotype 6B (Ps6B). Employing an improved reductive amination chemistry, 50% of Ps6B was incorporated to each protein, PspA1 and PspA3. The effect of chemical modifications in Ps6B and PspA was assessed by an antigenicity assay and circular dichroism, respectively. Fragmentation and oxidation decreased the antigenicity of Ps6B while conjugation improved antigenicity. In the same manner, introduction of adipic acid dihydrazide (ADH) reduced PspA secondary structure content, which was partially restored after conjugation. Immunization of Ps6B-PspA1 and Ps6B-PspA3 conjugates in mice induced specific IgG antibodies against the Ps6B and the protein; and anti-PspA antibodies had functional activity against two pneumococcal strains with different serotypes. These results suggest that chemical coupling between Ps6B and PspA did not affect antigenic epitopes and support the further development of PspA as a carrier protein in pneumococcal conjugate vaccines to provide broader protection.

Physical Properties of Biodegradable Poly(L-lactide) Induced by N, N -Bis(Benzoyl) 1, 3-Cyclohexanedicarboxylic Acid Dihydrazide as Crystallinity Additive

This work is aimed at synthesizing an organic compound N, N -bis(benzoyl) 1,3-cyclohexane-dicarboxylic acid dihydrazide (CABH) to focus on its effect on the non-isothermal crystallization of poly(L-lactide) (PLLA), meanwhile the melting behavior, thermal decomposition process and optical property of PLLA/CABH samples in different CABH concentrations were also investigated. It was found that CABH acted as efficient heterogeneous nucleating agent for inducing PLLA�s crystallization through comparative analysis of melt-crystallization process of the virgin PLLA with PLLA/CABH samples, and a high amount of CABH played a much more significant role in promoting PLLA�s crystallization. Additionally, the melt-crystallization processes also showed that both the cooling rate and the final melting temperature affected the crystallization behavior of PLLA, an increase of cooling rate could weaken the crystallization ability of PLLA/CABH samples, and the final melting temperature of 180�C made PLLA/CABH exhibit the best crystallization ability. For the cold-crystallization process, the cold-crystallization peak became flatter and shifted toward the lower temperature with increasing of CABH concentration, but an increase of heating rate could prevent the cold-crystallization peak from moving to low temperature because of the thermal inertia. The melting behaviors of PLLA/CABH depended on the previous crystallization and heating rate in heating, and the difference in melting behavior of PLLA/CABH samples effectively reflected the nucleation role of CABH, as well as the double melting peaks behavior of PLLA/CABH was thought to due to the melting-recrystallization. The introduction of CABH led to a drop in light transmittance, moreover, this negative effect were more obvious with an increase of CABH loading. In contrast, the fluidity of PLLA was significantly enhanced due to the existence of CABH.

Glycoconjugation of Shigella flexneri type 2a O-polysaccharide with CRM197 as a potential vaccine candidate for shigellosis

Shigellosis, a diarrheal disorder caused by an entero-invasive bacterium Shigella, is a major concern among children often leading to mortality. As most of these strains have developed universal antibiotic resistance, the development of a vaccine is crucial in combating the infection. The O-specific polysaccharide (O-PSs) from S. flexneri type 2a is considered to be the major disease-causing antigen in shigellosis. Therefore, the O-PSs conjugated with carrier proteins, can serve as a potential high molecular weight vaccine candidate. Accordingly, in the present study, O-PS extracted from S. flexneri 2a is conjugated with Cross-Reactive Material (CRM197), a non-toxic mutant of diphtheria toxin. We derivatized CRM197 and O-PS separately with adipic acid dihydrazide (ADH) and reacted with their counterparts to probe the conjugation efficacy. Among the two strategies, the CRM197-ADH treated with O-PS has yielded a stable glycoconjugate of 311 kDa. The conjugation efficiency has been probed by estimating the free protein, free O-PS and O-PS:CRM197 ratio using slot-blot, size exclusion and high-performance anion exchange chromatography techniques. The conjugate exhibited enhanced shelf-life of three months. The cytotoxicity studies with Vero/MRC-5 cells have confirmed the non-toxicity of the conjugate, which makes the glycoconjugate a potential vaccine candidate for shigellosis.

Effects of preparation parameters on the properties of the crosslinked pectin nanofiber mats

Pectin nanofiber mats prepared with periodate oxidation–electrospinning–adipic acid dihydrazide crosslinking strategy are promising for biomedical applications. In this study, we systematically examined the effects of electrospinning and crosslinking conditions on the properties of pectin nanofiber mats. The properties of mats were tunable in the range of 200–400 nm fiber size, 11–21% ADH residue content, 13–28 times absorbency, 13°–21° contact angle, 2 weeks or longer degradation time, 1.5–2.2 MPa tensile strength, 40–70% elongation, and 0.25–0.27 g/(cm2·24 h) permeability. Increasing polymer concentration, adipic acid dihydrazide amount, time or temperature could increase fiber size and its tensile strength, and decrease the absorbency, hydrophilicity, degradation rate, and elongation. These results indicate that controlling the process parameters can effectively regulate the properties of pectin nanofiber mats and meet the requirements of various biomedical applications.

Crosslinked carboxymethyl starch nanofiber mats: Preparation, water resistance and exudates control ability

The highly hydrophilic carboxymethyl starch (CMS) is promising for exudates control of highly exuding wounds. Its water intolerance hindered its application as wound dressings. This research has developed a new type of nanofiber mat with high hydrophilicity and water-resistance. The electrospun CMS nanofiber mats were crosslinked with the periodate oxidation – adipic acid dihydrazide crosslinking strategy. The crosslinked CMS nanofiber mats show wet mechanical strength between 1 and 5 MPa, can maintain good nanofibrous morphology and 90% of their initial mass after being incubated in simulated body fluid for 4 weeks, and have good biocompatibility. As wound dressings, they can evaporate exudates at speed between 0.30 and 0.34 g/(cm2·24 h) and absorb 10–20 times exudates rapidly. The crosslinked CMS nanofiber mats are promising dressings for the treatment of highly exuding wounds.