A novel in situ formed gel system with potential biodegradability and biocompatibility is developed by mixing the diblock and triblock poly(lactic acid)/poly(ethylene glycol) (PLA/PEG) copolymers with opposite configurations of PLA blocks. In situ gelation of such system is extremely fast, which happens within 10 s after mixing. In situ gelation, gel-to-sol transition, crystalline structure, microstructures, and mechanical properties of PLA-PEG/PLA-PEG-PLA enantiomerically mixed gels are significantly influenced by the mixing ratio, degree of polymerization for PEG block in triblock (DPPEG,tri) and diblock copolymers (DPPEG,di). It is found that in situ gelation of PLA-PEG/PLA-PEG-PLA enantiomeric mixture just happen at relatively smaller PLA-PEG/PLA-PEG-PLA mass ratio and larger DPPEG,tri. Hydrodynamic diameters of PLA-PEG and PLA-PEG-PLA copolymers in dilute solution increase remarkably upon mixing, indicating the formation of bridging networks. Stereocomplexed crystallites are formed for the PLA hydrophobic domains in PLA-PEG/PLA-PEG-PLA enantiomeric mixtures. As indicated by synchrotron-radiation SAXS analysis, the enantiomeric mixture changes from a compactly to loosely aggregated structure and the intermicellar distance enhances with increasing DPPEG,tri, DPPEG,di, or PLA-PEG-PLA fraction. Gelation mechanism of PLA-PEG/PLA-PEG-PLA enantiomeric mixture is proposed, in which part of PLA-PEG-PLA chains act as the connecting bridges between star and flower-like micelles and the stereocomplexed crystallites in micelle cores act as physically cross-linked points.
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http://dx.doi.org/10.1021/acs.jpcb.5b03610 | DOI Listing |
J Biomed Mater Res A
January 2025
Department of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran.
In situ gelling, cell-laden hydrogels hold promise for regenerating tissue lesions with irregular shapes located in complex and hard-to-reach anatomical sites. A notable example is the regeneration of neural tissue lost due to cerebral cavitation. However, hypoxia-induced cell necrosis during the vascularization period imposes a significant challenge to the success of this approach.
View Article and Find Full Text PDFGels
November 2024
Department of Pharmacy, College of Pharmacy, Ajou University, Suwon 16499, Republic of Korea.
The objective of this study was to investigate the physicochemical properties, drug release and in situ depot-forming behavior of alginate hydrogel containing poorly water-soluble aripiprazole (ARP) for achieving free-flowing injectability, clinically accessible gelation time and sustained drug release. The balanced ratio of pyridoxal phosphate (PLP) and glucono-delta-lactone (GDL) was crucial to modulate gelation time of the alginate solution in the presence of calcium carbonate. Our results demonstrated that the sol state alginate hydrogel before gelation was free-flowing, stable and readily injectable using a small 23 G needle.
View Article and Find Full Text PDFNanoscale Adv
December 2024
Institute of Chemical Technology, Vietnam Academy of Science and Technology 1A TL29 Street, District 12 Ho Chi Minh City 700000 Vietnam
In this study, we introduce an synthesis technique for incorporating gold nanoparticles (AuNPs) into a magnetic nanocomposite made of glucosamine and alginate (GluN/Alg) ionotropic gelation. GluN acted as a reducing agent for gold ions, leading to the formation of AuNPs which embedded in the nanocomposite FeO@GluN/Alg. Analytical techniques confirmed the crystallite structure of the nanocomposite AuNPs/FeO@GluN/Alg, which had an average size of 30-40 nm.
View Article and Find Full Text PDFJ Biomed Mater Res A
January 2025
Discipline of Mechanical, Manufacturing and Biomedical Engineering, Trinity College Dublin, Dublin 2, Ireland.
With no effective treatments for functional recovery after injury, spinal cord injury (SCI) remains one of the unresolved healthcare challenges. Human induced pluripotent stem cell (hiPSC) transplantation is a versatile patient-specific regenerative approach for functional recovery after SCI. Injectable electroconductive hydrogel (ECH) can further enhance the cell transplantation efficacy through a minimally invasive manner as well as recapitulate the native bioelectrical microenvironment of neural tissue.
View Article and Find Full Text PDFAdv Healthc Mater
December 2024
Dept of Biomedical Sciences. Institute of Clinical Sciences, University of Birmingham, Birmingham, UK.
Intra-articular glucocorticoid injections are effective in controlling inflammation and pain in arthritides but restricted by short duration of action and risk of joint degeneration. Controlled drug release using biocompatible hydrogels offers a unique solution, but limitations of in situ gelation restrict their application. Gellan sheared hydrogels (GSHs) retain the advantages of hydrogels, however their unique microstructures lend themselves to intra-articular application - capable of shear thinning under force but restructuring at rest to enhance residence.
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