In this study, Kraft lignin was partially depolymerized through base catalyzed depolymerization (BCD) in supercritical methanol to increase its solubility in organic solvents. The resulting partially ...depolymerized lignin (PDL) was then converted to lignin-based polycarboxylic acid (LPCA) by reacting with succinic anhydride. The hydroxyl value of PDL and acid value of LPCA were determined using 31P NMR. LPCA was used as a curing agent to cure a commercial epoxy (DER353). Because LPCA was a soft solid, glycerol tris(succinate monoester) (GTA) which was liquid at room temperature was also synthesized and used as cocuring agent and a diluent for LPCA. Dynamic mechanical properties and thermal stability of the cured epoxy resins were examined using dynamic mechanical analysis and thermogravimetric analysis, respectively. Results showed that curing of DER353 with the LPCA resulted in an epoxy resin with a moderate glass transition temperature (T g) and a storage modulus comparable to the resin cured with the commercial hexahydrophthalic anhydride (HHPA). However, thermal and thermal mechanical properties of the cured resins could be greatly regulated by using GTA or HHPA as a cocuring agent.
Based on the favorable biocompatibility, thermo-responsive hydrogels have attracted much attention. Therefore, more and more researchers have focused on the synthesis, characterizations and ...applications of thermo-responsive hydrogels.In this study, copolymer of P(N-hydroxymethyl acrylamide-
co
-diacetone acrylamide) P(NAM-
co
-DAA) with ketone groups were prepared to construct the thermo-responsive hydrogel through cross-linking induced thermo-response (CIT). The dihydrazide compounds were employed to cross-link the copolymer to make a self-healing hydrogel which containing ketone type reversible acylhydrazone bond. The resultant self-healing hydrogel has shown the excellent mechanical properties and chemical stabilities. At the same time, the hydrogel presented reversible gel-sol based on the pH value and group ratio. These thermo-responsive self-healing hydrogels also demonstrate wonderful biocompatibility, which extends its potential applications as biomaterials.
Self-healing hydrogels which have magical self-healing properties have attracted much attention in recent years. Here, we prepared a self-healing hydrogel with biocompatibility and NaHCO
3
...degradability. The hydrogel is constructed from cross-linking of poly(N,N-dimethyl acrylamide-
stat
-4-formylphenyl acrylate) P(DMA
-stat
-FPA) by pectin achlydrazide (pectin-AH). This hydrogel has base labile phenolic bonds connection and acylhydrazone bonds, which made the hydrogel degradable in extremely mild base of NaHCO
3
solution and showed self-healing property. At the same time, the pectin endowed the hydrogels with good biocompatibility and biodegradabilty. In addition, hydrogel has micro-porous structure and showed controlled drug release behavior. These excellent properties made this hydrogel very useful in biomedical fields such as tissue engineering, drug carriers and biosensors.
Pseudomonas aeruginosa (PA) is one of the leading pathogens responsible for hospital-acquired infections. With the increasing antibiotic resistance of PA, clinical treatment has become increasingly ...challenging. DNA vaccines represent a promising approach for combating PA infection. However, the immune response induced by a single antigen is limited, and combination vaccines hold greater therapeutic potential. The highly conserved OprF and PcrV genes are attractive candidate antigens for vaccine development, but the poor delivery of such vaccines has limited their clinical application. In this study, we constructed an OprF/PcrV bivalent DNA vaccine, and a polyaspartamide/polyethylene glycol di-aldehyde (PSIH/PEG DA) hydrogel was formulated to improve DNA delivery. The OprF/PcrV DNA vaccine formulated with the PSIH/PEG DA hydrogel was carefully characterized in vitro and in vivo and showed suitable compatibility. The PSIH/PEG DA hydrogel formulation induced a mixed Th1/Th2/Th17 immune response in mice, leading to a significant increase in antibody titers, lymphocyte proliferation rates, and cytokine levels compared to those in mice treated with single or combined vaccines. The PSIH/PEG DA hydrogel delivery system significantly enhanced the immune protection of the DNA vaccine in a murine pneumonia model, as revealed by the reduced bacterial burden and inflammation in the mouse lungs and increased survival rate. In conclusion, the PSIH/PEG DA hydrogel delivery system can further enhance the immune efficacy of the combination OprF/PcrV DNA vaccine. This research provides a novel optimized strategy for the prevention and treatment of PA infection using DNA vaccines.
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•We constructed a bivalent DNA vaccine against Pseudomonas aeruginosa, using a hydrogel as the vaccine delivery vehicle.•This vaccine elicited significant humoral and cellular immune responses in mice, enhancing the protective effect.•The vaccine shows promising potential in preventing Pseudomonas aeruginosa infections.
With biocompatibility and biodegradability, self-healing hydrogels prepared from biopolymers show great advantages in bioengineering and bioscience as drug delivery carrier. In this research, the ...biodegradable hydrogel was constructed based on poly(amino acid) of poly(aspartic acid) (PAsp) and pectin for in vivo antitumor applications as DOX release carrier. The PAsp bearing hydrazide groups and isopropyl groups (PAPH) was synthesized by ring opening of polysuccinimide (PSI) by isopropylamine and hydrazine, and used to fabricate fully biodegradable hydrogel with oxidized pectin (OPec) through dynamic acylhydrazone bond cross-linking. The regulatable mechanical strength of the hydrogel could adapt its bioapplication, and the excellent biocompatibility ensured biosafety in biomedical areas. Furthermore, the pectin backbone and the PAsp endowed the hydrogel with biodegradability both by enzyme and in vivo. The PAPH/Opec hydrogel as DOX carrier inhibited the tumor growth with the tumor weight 80% lower than the control group and reduced the in vivo toxicity of the DOX. As a result, this biodegradable PAPH/Opec hydrogel could find show great potential as sustained drug delivery vehicle in biomedical areas.
Aldehyde-modified hyaluronic acid (Ald-HA) was prepared and characterized by a variety of methods, and then Ald-HA was used as hydrogel skeleton to fabricate self-healing hydrogel with biocompatible ...polyethylene glycol diacylhydrazide (PEG DH) as cross-linkers. For this purpose, aqueous solutions of Ald-HA and PEG DH solutions with different molecular weight were used to prepare HA-based hydrogel for potential applications in biological applications. This novel biodegradable hydrogel behaved with good mechanical properties and self-repairing performance. Moreover, the hydrogels have good porous structure fit for controlled release of doxorubicin (DOX∙HCl) and showed successive slow release profile. Importantly, CCK-8 assay demonstrated that the HA-based hydrogel possessed good cytocompatibility to JB6 P + cells. The 3D cell culture experiment reveals that the hydrogel acted as a good framework for cell growth and reproduction. These experiments indicate that the new HA-based hydrogel has excellent bio-compatibility for both preclinical and clinical applications.
Nanomaterial with variable d‐spacing is prepared by hydrolysis of a bulk self‐assembly with lamellar morphology. The bulk self‐assembly is prepared from a disulfide‐containing ...polystyrene–(S2)poly(tert‐butyl acrylate)–polystyrene (PS–(S2)PtBA–PS) triblock copolymer, which is polymerized via two‐step atom transfer radical polymerization (ATRP) with a disulfide‐containing difunctional initiator. The results show that the PS–(S2)PtBA–PS with 47.6% weight fraction of PS bulk self‐assembles into ordered nanomaterial with lamellar morphology. As the morphology of the bulk material is fixed by glassy PS microdomains, the PtBA domains can be hydrolyzed to poly(acrylate acid) (PAA) domains in the bulk state of PS and then the d‐spacing can be regulated like an accordion by changing the environment of the material. Also, the hydrolyzed self‐assembly can be applied as a template to load nanoparticles in PAA microdomains to prepare layered inorganic/organic composites. The bulk material can be dispersed in methanol to form dispersed (multilayered) nanoplates by cleaving the disulfide bonds by tributylphosphine (Bu3P) reduction. Moreover, the ester bonds in the hydrolyzed bulk material can be cleaved by NaOH, and then water‐dispersed (multilayered) nanoplates with pH responsivity are obtained.
Nanomaterial with variable d‐spacing regulated like an accordion is prepared from disulfide‐containing (PS–(S2)PtBA–PS) triblock copolymer with a lamellar morphology. The accordion‐like material can be used as a template to prepare layered inorganic/organic composites or be cleaved to prepare dispersed nanoplates.
Self-healing hydrogels have drawngreat attention in the past decade since the self-healing property is one of the characteristics of living creatures. In this study, poly(acrylamide-stat-diacetone ...acrylamide) P(AM-
-DAA) with a pendant ketone group was synthesized from easy accessible monomers, and thermo-responsive self-healing hydrogels were prepared through a series of diacylhydrazide compounds cross-linking without any additional stimulus. Although the copolymers do not show thermo-response, the hydrogels became thermo-responsive andboth the lower critical solution temperature (LCST) and upper critical solution temperature (UCST) varied with the composition of the copolymer and structure of cross-linkers. With a dynamic covalent bond connection, the hydrogel showed gel-sol-gel transition triggered by acidity, redox, and ketone to acylhydrazide group ratios. This is another interesting cross-linking induced thermo-responsive (CIT) hydrogel with different properties compared to PNIPAM-based thermo-responsive hydrogels. The self-healing hydrogel with CIT properties could have great potential for application in areas related to bioscience, life simulation, and temperature switching.
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