Hybrid gels by conjugation of hyaluronic acid with poly(itaconic anhydride-co-3,9-divinyl-2,4,8,10-tetraoxaspiro (5.5)undecane) copolymers

Chitosan-Stabilized Lipid Vesicles with Indomethacin for Modified Release with Prolonged Analgesic Effect: Biocompatibility, Pharmacokinetics and Organ Protection Efficacy

Background/Objectives: Indomethacin (IND) is a widely used non-steroidal anti-inflammatory drug (NSAID) effective in managing pain and inflammation. However, its therapeutic use is often limited by gastrointestinal irritation and low bioavailability. This study aimed to evaluate the biocompatibility, release kinetics, and analgesic potential of IND-loaded chitosan (CHIT)-stabilized lipid vesicles (IND-ves) in comparison to free IND, focusing on their in vivo effects and impact on somatic nociceptive reactivity in mice. Methods: IND-ves were prepared using a molecular droplet self-assembly technique, followed by CHIT coating to enhance stability and control drug release. Mice were administered either free IND or IND-ves, and various physiological parameters, including liver and kidney function, oxidative stress markers, immune cell activity, and histopathological changes in key organs, were assessed. Plasma drug release kinetics and analgesic effects were evaluated using the tail-flick test. Results: Both IND and IND-ves demonstrated good biocompatibility, with no significant changes in hematological, biochemical, or immunological profiles. IND-ves exhibited a sustained release profile, with drug release initiating at 30 min and peaking at 3 h, while free IND displayed a rapid release and potential gastric mucosal damage. IND-ves did not induce oxidative stress or inflammation and maintained organ integrity, particularly protecting against gastric injury. Additionally, the prolonged release profile of IND-ves contributed to extended analgesic effects in the tail-flick test. Conclusions: CHIT-stabilized lipid vesicles offer a promising drug delivery system for IND, enhancing drug release, prolonging analgesic efficacy, and minimizing gastrointestinal irritation. These findings suggest that IND-ves could serve as a safer and more effective alternative for NSAID therapy.

The Programmable Nature of Drug-Polymer Systems and Its Implications

In our work, we use the multifractal motion theory to apply a multifractal state density conservation law to the polymer-drug release process. This law is specific to the transition from multifractal to nonmultifractal curves corresponding to the polymer-drug release processes. A multifractal diffusion-type law was obtained, which describes the cyclic drug release dynamics until the polymer matrix is fully degraded. The polymer-drug system reveals a programmable nature due to its complex part and scale resolution dependence.

Hydrogels with Antioxidant Microparticles Systems Based on Hyaluronic Acid for Regenerative Wound Healing

This research focuses on the synthesis of hydrogels exhibiting enhanced antioxidant properties derived from hyaluronic acid (HA) and poly(ethylene brassylate-co-squaric acid) (PEBSA), a copolymacrolactone that have the ability to be used in drug delivery applications. Quercetin (Q), a bioflavonoid with strong antioxidant properties, is employed as a bioactive compound. The biomolecule is encapsulated in the polymeric network using different entrapment techniques, including the initial formation of a complex between PEBSA and Q, which is demonstrated through the dynamic light scattering technique. Fourier transform infrared spectroscopy (FT-IR) and rheological studies confirm the formation of the hydrogels, revealing the occurrence of physical interactions between the synthetic polymer and the polysaccharide. Moreover, the hydrogels demonstrate biocompatible properties after direct contact with the HDFa cell line and antioxidant properties, as revealed by DPPH tests.

Biomedical applications of stimuli-responsive "smart" interpenetrating polymer network hydrogels

In recent years, owing to the ongoing advancements in polymer materials, hydrogels have found increasing applications in the biomedical domain, notably in the realm of stimuli-responsive "smart" hydrogels. Nonetheless, conventional single-network stimuli-responsive "smart" hydrogels frequently exhibit deficiencies, including low mechanical strength, limited biocompatibility, and extended response times. In response, researchers have addressed these challenges by introducing a second network to create stimuli-responsive "smart" Interpenetrating Polymer Network (IPN) hydrogels. The mechanical strength of the material can be significantly improved due to the topological entanglement and physical interactions within the interpenetrating structure. Simultaneously, combining different network structures enhances the biocompatibility and stimulus responsiveness of the gel, endowing it with unique properties such as cell adhesion, conductivity, hemostasis/antioxidation, and color-changing capabilities. This article primarily aims to elucidate the stimulus-inducing factors in stimuli-responsive "smart" IPN hydrogels, the impact of the gels on cell behaviors and their biomedical application range. Additionally, we also offer an in-depth exposition of their categorization, mechanisms, performance characteristics, and related aspects. This review furnishes a comprehensive assessment and outlook for the advancement of stimuli-responsive "smart" IPN hydrogels within the biomedical arena. We believe that, as the biomedical field increasingly demands novel materials featuring improved mechanical properties, robust biocompatibility, and heightened stimulus responsiveness, stimuli-responsive "smart" IPN hydrogels will hold substantial promise for wide-ranging applications in this domain.

Evaluation of hyaluronic acid-polymacrolactone hydrogels with 3D printing capacity

The implementation of personalized patches, tailored to individual genetic profiles and containing specific amounts of bioactive substances, has the potential to produce a transformative impact within the medical sector. There are several methods of designing scaffolds in the context of personalized medicine, with three-dimensional (3D) printing emerging as a pivotal technique. This innovative approach can be used to construct a wide variety of pharmaceutical dosage forms, characterized by variations in shape, release profile, and drug combinations, allowing precise dose individualization and the incorporation of multiple therapeutic agents. To expand the potential and applicability of personalized medicine, particularly with regards to indomethacin (IND), a drug necessitating individualized dosing, this study proposes the development of new transdermal delivery systems for IND based on hyaluronic acid and a polylactone synthesized within our research group, namely poly(ethylene brasilate-co-squaric acid) (PEBSA). The obtained systems were characterized in terms of their swelling capacity, rheological behavior, and morphological characteristics that highlighted the formation of stable three-dimensional networks. To impart specific shape and geometry to the structures, multi-component systems based on PEBSA, HA, and methacrylate gelatin were obtained. The scaffolds were loaded with IND and subsequently 3D printed. The release capacity of IND and its dependence on the relative ratios of the components comprising the scaffold composition were highlighted. The cytocompatibility studies revealed the successful development of biocompatible and noncytotoxic systems.

New Hydrogel Network Based on Alginate and a Spiroacetal Copolymer

This study reports a strategy for developing a biohybrid complex based on a natural/synthetic polymer conjugate as a gel-type structure. Coupling synthetic polymers with natural compounds represents an important approach to generating gels with superior properties and with potential for biomedical applications. The study presents the preparation of hybrid gels with tunable characteristics by using a spiroacetal polymer and alginate as co-partners in different ratios. The new network formation was tested, and the structure was confirmed by FTIR and SEM techniques. The physical properties of the new gels, namely their thermal stability and swelling behavior, were investigated. The study showed that the increase in alginate content caused a smooth increase in thermal stability due to the additional crosslinking bridges that appeared. Moreover, increasing the content of the synthetic polymer in the structure of the gel network ensures a slower release of carvacrol, the encapsulated bioactive compound.

New Physical Hydrogels Based on Co-Assembling of FMOC-Amino Acids

In the last years, physical hydrogels have been widely studied due to the characteristics of these structures, respectively the non-covalent interactions and the absence of other necessary components for the cross-linking processes. Low molecular weight gelators are a class of small molecules which form higher ordered structures through hydrogen bonding and π-π interactions. In this context it is known that the formation of hydrogels based on FMOC-amino acids is determined by the primary structures of amino acids and the secondary structure arrangement (alpha-helix or beta-sheet motifs). The present study aimed to obtain supramolecular gels through co-assembly phenomenon using FMOC-amino acids as low molecular weight gelators. The stability of the new structures was evaluated by the vial inversion test, while FTIR spectra put into evidence the interaction between the compounds. The gel-like structure is evidenced by viscoelastic parameters in oscillatory shear conditions. SEM microscopy was used to obtain the visual insight into the morphology of the physical hydrogel network while DLS measurements highlighted the sol-gel transition. The molecular arrangement of gels was determined by circular dichroism, fluorescence and UV-Vis spectroscopy.

Cyclic Anhydrides as Powerful Tools for Bioconjugation and Smart Delivery

Cyclic anhydrides are potent tools for bioconjugation; therefore, they are broadly used in the functionalization of biomolecules and carriers. The pH-dependent stability and reactivity, as well as the physical properties, can be tuned by the structure of the cyclic anhydride used; thus, their application in smart delivery systems has become very important. This review intends to cover the last updates in the use of cyclic anhydrides as pH-sensitive linkers, their differences in reactivity, and the latest applications found in bioconjugation chemistry or chemical biology, and when possible, in drug delivery.

Advancement in the Biomedical Applications of the (Nano)gel Structures Based on Particular Polysaccharides

(Nano)gels from macromolecular compounds-natural, synthetic, or a combination thereof, suitable crosslinkers-and conferred characteristics-such as degradability, size, charge, amphiphilicity, responsiveness, and softness-are capable of responding to the challenges imposed by bioengineering applications. Polysaccharide-based gels have received particular attention in this field. This review addresses recent advancement in the use of (nano)gel structures prepared only from compounds based on gellan gum, heparin, chondroitin sulfate, carrageenan, guar gum, galactose, or agarose, which represent an important part of the special class of natural polymers, the polysaccharides. Also, future trends are taken into discussion regarding the (nano)gels' use in biomedical applications such as biomimetics, biosensors, artificial muscles, and chemical separations in relation with their ability to be used as a vehicle for various biomolecules due to their physicochemical properties, biocompatibility, and biodegradability.