Hyaluronic Acid: The Influence of Molecular Weight on Structural, Physical, Physico-Chemical, and Degradable Properties of Biopolymer

Effects of molecular weights on the bioactivity of hyaluronic acid: A review

Hyaluronic acid (HA), the only non-sulfated glycosaminoglycan (GAG), is essential for maintaining the extracellular matrix's structural and functional integrity. Its bioactivity is determined by interactions between HA fragments of different molecular weights and specific receptors, which influence downstream signaling pathways. This review systematic summarizes the correlation between HA molecular weight dynamic changes and bioactivities focusing on imbalance of HA degradation and metabolism due to various pathological processes. Outline the core transduction mechanisms of HA receptors and signaling pathways, and innovatively hypothesize that discrepancies in cellular distribution with HA-molecular weights dependent lead to the activation of different signaling pathways from the perspective of molecular weight affecting cellular distribution. Finally, it addresses challenges in studying HA's biofunctions and provides new perspectives for future research.

A novel empirical and rheometric assessment of viscoelastic hydrogel implant cohesiveness

Therapeutic implantable hydrogels are increasingly utilized in medicine due to their versatile viscoelastic properties. Nonetheless, the clinical efficacy and longevity of these products is predicated on their ability to retain structural integrity post-implantation. Gel cohesion, defined as the capacity to resist fragmentation, has lacked empirical standardization, especially in high shear environments, with present methods often conflating this mechanical parameter with gel ductility or qualitative perceptions of tackiness. In this study, we introduce a novel quantitative method of cohesion analysis termed the Modulus of Cohesion (MOC). The MOC is derived from rheometric strain sweep testing by calculating the difference between the elastic and viscous moduli from 0% strain to the crossover point. This novel parameter provides a direct measure of mechanical energy storage and dissipation balance, accounting for linear and nonlinear deformation in shear strain. Eleven commercially available hyaluronic acid gels are evaluated using this method, alongside uniaxial tension and drop weight methods to establish correlations between MOC and existing cohesion metrics. Additionally, haptic sensory analysis and aqueous dispersion methods from previous reports are correlated with rheometric and mechanical tests. Our results demonstrate that MOC provides a reliable, reproducible measure of gel cohesiveness, correlating strongly with other quantitative methods with augmented precision.

Management of Oxidative Stress and Inflammation in Patients with Symptomatic Dry Eye Disease Treated with a Preservative-Free Ophthalmic Emulsion Combining Alpha-Lipoic Acid and High Molecular Weight Sodium Hyaluronate

INTRODUCTION

This study aimed to explore the beneficial effect of a preservative-free (PF) emulsion eyedrop combining high molecular weight sodium hyaluronate (HMW-HA) and alpha-lipoic acid on oxidative stress and ocular surface inflammation in patients with dry eye disease (DED).

METHODS

In this prospective exploratory study, patients with moderate to severe DED symptoms were treated with the study eyedrop, 4-6 times/day for 1 month. Two visits were scheduled: baseline (D0) and after 35 days (D35). The following parameters were assessed: quality of life (OSDI score); superoxide dismutase (SODase) concentration in tears; goblet cell (GC) density (impression cytology); conjunctival hyperemia (Efron scale); corneal, conjunctival, and eyelid staining (Oxford scale); and meibomian gland (MG) blockage. Data were compared between D0 and D35 in subgroups of patients with a significant abnormality of the study outcome at baseline.

RESULTS

Forty patients were involved, with a highly significant improvement of OSDI score at D35. The mean concentration of SODase significantly increased by 3.2 and 2.4 times for SODase1 and SODase2 respectively, in patients with deficient SODase at baseline. In patients with abnormal GC density at baseline, GC count increased by five times at D35. Conjunctival hyperemia and corneal staining scores significantly improved in the subpopulation of patients with a baseline grade ≥ 2. Eyelid margin staining was significantly reduced at D35 in patients with significant abnormalities at baseline. A significant reduction of MG obstruction was shown in the lower eyelid in patients with significant blockage at baseline.

CONCLUSION

The use of a PF ophthalmic emulsion combining alpha-lipoic acid and HMW-HA shows a beneficial effect on the ocular surface through the improved quality of life score. Noteworthy, patients presenting high oxidative and inflammatory conditions experienced significant improvement in oxidative stress and inflammation markers; this synergic effect is likely due to the well-known properties of alpha-lipoic acid and HMW-HA, enhancing DED management.

TRIAL REGISTRATION

ISRCTN.com identifier, 17861788.

Pharmacokinetics of the systemic application of hyaluronic acid for joint arthritis treatment

Frequent degenerative joint diseases, known as arthritis, are characterized by joint inflammation and cartilage breakdown. Various arthritis types are traditionally managed with intraarticular injections of hyaluronan or its derivatives. However, intravenous administration of hyaluronan is emerging as a vital alternative, particularly because intraarticular injections can be challenging for clinicians when targeting small or swollen joints. Pharmacokinetics of intravenously and intraperitoneally administered middle-Mw hyaluronan were studied in an adjuvant-induced arthritis mouse model alongside therapeutic effects. Using 13C-, biotin- and fluoresce-labeling, we found hyaluronan accumulated in inflamed joint tissues while distribution in other organs remained similar to healthy controls. Repeated administrations significantly reduced arthritis symptoms like swelling and redness, RANKL, inducible nitric oxide synthase, COMP and prostaglandin E2 levels. Moreover, hyaluronan treatment prevented dextran-FITC penetration into inflamed paws suggesting reduced vascular permeability at the site of inflammation. These findings support systemic hyaluronan administration as a promising arthritis treatment strategy.

Expression and molecular characterization of an intriguing hyaluronan synthase (HAS) from the symbiont "Candidatus Mycoplasma liparidae" in snailfish

Background

Hyaluronan synthases (HASs) are ubiquitous in living organisms, and the hyaluronic acid (HA) synthesized by them are important to their body and well used in medicine, cosmetics and other fields. HAS from deep-sea creatures has not yet been explored before. The study aims to analyse the characteristics and enzyme kinetics of a novel hyaluronan synthase derived from the symbiont "Candidatus Mycoplasma liparidae" found in deep-sea snailfish (snHAS).

Methodology

snHAS was over-expressed using His 6 as tag in the study. The sequence alignment was conducted by Cluster W and then the phylogenetic analyse of HASs was performed by Mega 6.0 to investigate the position of snHAS during evolution. K m and V max were detected to study the enzyme kinetics of snHAS wildtype and its mutant. The molecular weight of HA was evaluated by high performance gel permeation chromatography (HPGPC). The cardiolipin was added to investigate whether it had a promoting effect on the snHAS.

Results

The length of snHAS was 933 bp with an open reading frame (ORF) of 310 amino acids. Unlike other repoted HASs, snHAS had no transmembrane region and was not classified into the currently known Class I or Class II. snHAS could synthesize hyaluronan with lower molecular weights using the substrates of uridine-diphosphate-N-acetylglucosamine (UDP-GlcNAc) and uridine-diphosphate-glucuronic acid (UDP-GlcA) in vitro. The K m values of snHAS were 258 ± 45 µM and 39 ± 5 µM for UDP-GlcNAc and UDP-GlcA, respectively, much lower than those from mice (K m for UDP-GlcA: 55 ± 5 µM; K m for UDP-GlcNAc: 870 ± 60 µM). The k cat/K m values of snHAS were 163.5 s-1 mM-1 and 8.08 s-1 mM-1 for UDP-GlcA and UDP-GlcNAc, respectively. Furthermore, the activity of snHAS was independent of cardiolipin.

Conclusions

snHAS was a novel HAS based on the characteristics of the animo acid sequence, which could produce low molecular weight of HA with high efficiency. This provides a molecular basis for the biosynthesis of low molecular weight of HA.

Multilamellar hyaluronic acid-b-poly(lactic acid) polymersomes for pathology-responsive MRI enhancement

This study introduces a biocompatible, stimuli-responsive imaging and therapeutic delivery system using ultrasmall iron oxide nanoparticles (USPIONs) encapsulated within the hyaluronic acid-b-poly(lactic acid) (HA-PLA) polymersome membrane, with a model protein bovine serum albumin in the core. These multilamellar vesicles exhibit enhanced T2-weighted MRI contrast, achieving a relaxivity 3-fold higher than existing agents. The polymersomes demonstrate acid- and enzyme-triggered degradation, enabling controlled release and measurable contrast changes in pathological environments. Preliminary in vivo and postmortem studies confirm their strong imaging performance, high biocompatibility, and targeted response to enzymatic, acidic microenvironments, paving the way for theranostic applications in disease diagnosis and treatment monitoring.

Unlocking the Rich Potential of a Soft Gel-Cream Enriched with Royal Jelly for Topical Use

For decades, royal jelly achieved notoriety and became an ultra-rich ingredient with numerous pharmacological properties especially for its use in production of topical ointments and creams. A novel formulation enriched with 2% royal jelly has been developed and characterized. Rheological results highlight a gel-like behavior of the product in the packaging, as it does not flow from the costumer's hand after application and behaves like a liquid, spreading evenly onto clean skin. A clear comparison in size distribution of pure and cream samples was noticed by dynamic light scattering analysis and completed further by Fourier transform infrared spectroscopy (FTIR-ATR) which showed off shift changes in the gel sample as compared to pure compounds. MTT assays were conducted in quintuplicate on murine fibroblasts cell line (NCTC L-929) for testing the biocompatibility of the product in the range of 50-1000 μg/mL over 24, 48 and 72 h. The designed formulation is typically intended to deliver active compounds to the skin surface and potentially into deeper layers. A molecular docking study was performed for binding mode prediction of P-gp protein residues with two ligands, quercetin and myricetin, in order to investigate their role in the internal modulation of drug transport across cell membranes within the skin.

Hyaluronate-incorporated edaravone nanostructured lipid carriers for nose-to-brain targeting- biphasic DoE optimization, pharmacokinetic, and brain distribution studies

The present research aimed to develop nasal delivery for edaravone (EDR), a BCS class-IV neuroprotective agent. EDR nanostructured lipid carriers (EDR NLCs) were developed by melt-emulsification probe sonication using Geleol™ (solid lipid), Miglyol®812N and coconut oil (liquid lipid), Tween 20 (surfactant), Lipoid S75 (emulsifier) and sodium hyaluronate (SH) as mucoadhesive agent. A biphasic optimization approach for NLCs was implemented using the Plackett-Burman design and Box-Behnken design to comprehensively understand key formulation and process variables affecting critical attributes of NLCs. The mucoadhesive strength of optimized EDR-SH NLCs was 2.22-fold higher than EDR NLCs. Drug release of NLCs was 2-fold higher than EDR. The partial amorphous nature of EDR in the NLC matrix was evident from DSC and XRD results. A pharmacokinetic study in rats revealed that EDR-SH NLCs exhibited 4.42-fold, 1.27-fold and 8.75-fold enhanced AUC than EDR, EDR NLCs and marketed formulation. In brain distribution, drug targeting efficiency and direct transport percentage of EDR-SH NLCs were 2.4-fold, 1.17-fold higher than EDR, indicating efficient brain targeting via direct pathways. Thus, nasal delivery of EDR-SH NLCs improves brain targeting and provides a self-administration alternative for long-term use to mitigate neurological disorders.

Innovative applications of natural polysaccharide polymers in intravesical therapy of bladder diseases

Natural polysaccharide polymers, characterized by their remarkable biocompatibility, biodegradability, and structural versatility, hold great promise for intravesical therapy in treating of bladder diseases. Conditions such as bladder cancer and interstitial cystitis compromise drug efficacy by affecting the permeability of the bladder wall. Traditional therapeutic approaches are often hindered by physiological challenges, including rapid drug clearance and the intrinsic permeability barrier of the bladder. Polysaccharides like hyaluronic acid (HA) and chitosan (CS) have emerged as promising materials for intravesical drug delivery systems (IDDS), owing to their ability to repair tight junctions in the bladder wall, mitigate inflammation, and enhance permeability. This review provides a comprehensive overview of the mechanisms through which polysaccharide-based natural polymers regulate bladder wall permeability and highlights their advancements in delivery platforms, including nanoparticles, hydrogels, floating systems, and composite materials. By improving drug retention, enhancing bioavailability, and promoting patient adherence, these materials offer a solid foundation for the development of innovative therapeutic strategies for bladder diseases.

Double-Network Hydrogel Based on Methacrylated Chitosan/Hyaluronic Acid Coacervate for Enhanced Wet-Tissue Adhesion

Developing robust wet tissue adhesives remains challenging due to interfacial water and irregular surfaces. While polyelectrolyte coacervates demonstrate promising hydrophobic/fluidic properties for wet adhesion, their low cohesion limits practical applications. Herein, a wet tissue bioadhesive based on coacervates formed from low- molecular-weight methacrylated chitosan (CSMA) and hyaluronic acid (HA) is reported. These homogeneous and transparent coacervates displayed high solid content (∼18.0%), fluidity (∼105 mPa·s), and tunable mechanical properties. Upon application to wet tissue surfaces, the coacervate can be photo-cross-linked to form a double-network hydrogel in situ, resulting in improved cohesion and durable adhesion. The resulting CSMA-HA hydrogel demonstrated robust adhesion to tissues, with a bursting pressure of 374 mmHg. Remarkably, the bursting pressure can be further enhanced (∼623 mmHg) after 24 h of PBS immersion due to dynamic bond reorganization and low swelling. The demonstrated stability under physiological conditions and robust wet adhesion position CSMA-HA coacervates as a transformative platform for tissue adhesive applications.

Surface engineering as a potential strategy to enhance desiccation tolerance of beneficial bacteria

Desiccation can diminish the viability of beneficial bacteria by over 90%, threatening their effectiveness in agricultural productivity and probiotic applications. Bacterial surface engineering, already proven to combat acidic environments and oxidative damage, offers promising avenues for mitigating desiccation stress. This Perspective explores and adapts these approaches-spanning bioinspired coatings, encapsulation methods, and nanotechnology-to significantly improve bacterial survival under dehydration. By slowing water loss, preserving membrane integrity, and minimizing oxidative damage, surface engineering paves the way for scalable and effective strategies to bolster bacterial resilience in demanding environments.

Muscle physiology in spasticity and muscle stiffness

This paper examines the physiological changes in spastic muscles contributing to spasticity and muscle stiffness, focusing on the underlying mechanisms and their clinical implications. Spasticity, which is prevalent in neurological conditions such as multiple sclerosis, cerebral palsy, spinal cord injury, stroke, and traumatic brain injury, is characterized by disordered sensorimotor control and often results in increased muscle stiffness and resistance to movement. Recent developments in the understanding of spasticity suggest the importance of architectural changes in muscles that may contribute to increased passive resistance, potentiate reflex mechanisms, and progression to fibrosis, with hyaluronan (HA), a glycosaminoglycan, playing a pivotal in modulating the properties of the muscle extracellular matrix (ECM). The hyaluronan hypothesis of muscle stiffness postulates that the accumulation and biophysical alteration of HA in the ECM of muscle increases its viscosity, resulting in increased passive mechanical resistance. This is turn mayincrease muscle sensitivity to stretch, potentiating spasticity, and lead to cellular differentiation of myofibroblasts to fibroblasts ultimately leading to fibrosis and contracture. A deeper understanding of HA's role in ECM dynamics offers promising avenues for novel treatments aimed at mitigating stiffness and preventing long-term disability in patients with spasticity.

Hyaluronic Acid and Skin: Its Role in Aging and Wound-Healing Processes

Hyaluronic acid (HA) is a linear, unbranched polysaccharide classified as a glycosaminoglycan. While HA is found in various tissues throughout the body, over half of its total proportion is found in the skin. The role of HA in the skin is complex and multifaceted. HA maintains proper hydration, elasticity, and skin firmness, serving as a key extracellular matrix (ECM) component. With age, HA production gradually decreases, leading to reduced water-binding capacity, drier and less elastic skin, and the formation of wrinkles. Additionally, HA plays an active role in the wound-healing process at every stage. This review summarizes the current background knowledge about the role of HA in skin aging and wound healing. We discuss the latest applications of HA in aging prevention, including anti-aging formulations, nutricosmetics, microneedles, nanoparticles, HA-based fillers, and skin biostimulators. Furthermore, we explore various HA-based dressings used in wound treatment, such as hydrogels, sponges, membranes, and films.

Recent advances in hyaluronic acid-based hydrogels for diabetic wound healing

Diabetic wound healing represents a complex biological challenge, often impeded by disrupted cellular processes and dysregulated inflammation, which can lead to chronic and non-healing wounds. Given the significant burden on patients and the healthcare system, there is an urgent need for advanced therapeutic strategies. Hyaluronic acid (HA)-based hydrogels have emerged as a promising solution due to their biocompatibility, biodegradability, and unique physiological functions. This review aims to provide a comprehensive overview of recent advances in HA-based hydrogels, highlighting their potential in addressing diabetic wound complications. Specifically, it examines challenges such as hyperglycemia-induced oxidative stress and impaired cellular signaling within the intricate diabetic wound microenvironment. Moreover, the review explores the composition and properties of HA, including its adhesive capabilities and role in reducing surgical trauma. Various crosslinking strategies and functional modifications are also discussed to endow HA-based hydrogels with antioxidant, antimicrobial, and growth factor-releasing capabilities. By summarizing the latest research and identifying areas for further exploration, this review contributes to the development of more effective HA-based hydrogel formulations for diabetic wound healing.

Preparation of polysaccharide-surfactant modified gliadin nanoparticles and loading with resveratrol

In the presented research, environmentally friendly, nontoxic, and biodegradable nanoparticles were synthesized from gliadin, hyaluronic acid (HA), and sophorolipid (SPL) for the delivery of resveratrol (Res). The incorporation of HA and SPL leads to an increase in nanoparticle size. The unfolding of proteins was facilitated by HA and SPL through non-covalent interactions. Res-loaded gliadin nanoparticles modified with surfactant-polysaccharides (GHS/RNPs) exhibited the highest encapsulation efficiency of Res. Molecular docking analyses revealed that the binding between Res and gliadin primarily involved hydrogen bonds, π-alkyl interactions, electrostatic forces, and van der Waals attractions, findings that were corroborated by spectroscopic investigations. The GHS/RNPs demonstrated superior stability and sustained Res retention across various conditions. Intriguingly, during in vitro gastrointestinal digestion, the HA and SPL components within the nanoparticle shell facilitated the controlled release of Res, significantly enhancing its bioavailability in the small intestine. This study holds significant implications for advancing gliadin-based oral delivery systems for bioactive compounds in both the food and pharmaceutical sectors.

Microbial production of hyaluronic acid: The current advances, engineering strategies and trends

Hyaluronic acid (HA) is a versatile biomolecule with applications in medicine, cosmetics, and pharmaceuticals. While traditionally extracted from animal tissues, HA is now predominantly produced through microbial fermentation. Microbial fermentation using strains such as Streptococcus zooepidemicus, Corynebacterium glutamicum, and Bacillus subtilis offers a more scalable and sustainable alternative to chemical and animal extraction methods. Recent studies reveal promising yields from engineered strains of Corynebacterium glutamicum and Bacillus subtilis, utilizing advanced metabolic and genetic techniques. Recent advancements in genetic and metabolic engineering, as well as synthetic biology, have addressed some challenges related to molecular weight, viscosity, and by-product formation. This review focuses on the microbial production of HA using engineered strains, encompassing producer organisms, metabolic engineering strategies, industrial-scale production, and key factors influencing molecular weight. Furthermore, it addresses the challenges and potential solutions associated with HA production. Additional research is necessary to develop more efficient and robust engineered strains that exhibit resistance to contamination and can utilize low-cost substrates, such as Pseudomonas putida and Halomonas spp. By overcoming these challenges, researchers can advance the industrial production of HA and expand its applications, thereby contributing to the growth of the HA market.

Hyaluronic acid-functionalized nanomedicines for CD44-receptors-mediated targeted cancer therapy: A review of selective targetability and biodistribution to tumor microenvironment

Cancer is a leading cause of death globally, driven by late diagnoses, aggressive progression, and multidrug resistance (MDR). Advances in nanotechnology are tackling these challenges, paving the way for transformative cancer treatments. Hyaluronic acid (HA)-based nanoparticles (NPs) have emerged as promising platforms due to their biocompatibility, biodegradability, and natural targeting capabilities via CD44 (cluster of differentiation 44) receptors. Functionalizing NPs with HA enhances cellular uptake through CD44, improves pharmacokinetics, tumor localization, and anticancer efficacy while reducing systemic toxicity. This review provides a comprehensive overview of HA-based NPs, highlighting their potential to address limitations in cancer treatment and inspire further innovation. The targeting efficiency of HA-based NPs can be further optimized by integrating passive (e.g., PEGylation), active (e.g., ligand conjugation), and stimuli-responsive mechanisms (e.g., pH, redox, light, enzyme activity, and temperature sensitivity). These NPs also enable therapeutic combinations, such as co-delivery of chemotherapeutics with gene therapies (e.g., siRNA) and integration of photothermal and photodynamic therapies, alongside immune checkpoint inhibitors, amplifying therapeutic synergy. Despite promising preclinical results, challenges such as scalability, stability, long-term safety, ethical and regulatory hurdles, and high costs persist. Nonetheless, HA-based NPs represent a cutting-edge approach, combining biocompatibility, precision targeting, and multimodal functionality to combat cancer effectively, while mitigating side effects.

Novel Buccal Xanthan Gum-Hyaluronic Acid Eutectogels with Dual Anti-Inflammatory and Antimicrobial Properties

Buccal drug delivery systems often struggle with poor drug solubility, limited adhesion, and rapid clearance, leading to suboptimal therapeutic outcomes. To address these limitations, we developed a novel hybrid eutectogel composed of xanthan gum (XTG), hyaluronic acid (HA), and a Natural Deep Eutectic Solvent (NADES) system (choline chloride, sorbitol, and glycerol in 2:1:1 mole ratio), incorporating 2.5% ibuprofen (IBU) as a model drug. The formulation was optimized using a face-centered central composite design to enhance the rheological, textural, and drug release properties. The optimized eutectogels exhibited shear-thinning behavior (flow behavior index, n = 0.26 ± 0.01), high mucoadhesion (adhesiveness: 2.297 ± 0.142 N·s), and sustained drug release over 24 h, governed by Higuchi kinetics (release rate: 237.34 ± 13.61 μg/cm2/min1/2). The ex vivo residence time increased substantially with NADES incorporation, reaching up to 176.7 ± 23.1 min. An in vivo anti-inflammatory evaluation showed that the eutectogel reduced λ-carrageenan-induced paw edema within 1 h and that its efficacy was sustained in the kaolin model up to 24 h (p < 0.05), achieving comparable efficacy to a commercial 5% IBU gel, despite a lower drug concentration. Additionally, the eutectogel presented a minimum inhibitory concentration for Gram-positive bacteria of 25 mg/mL, and through direct contact, it reduced microbial viability by up to 100%. Its efficacy against Bacillus cereus, Enterococcus faecium, and Klebsiella pneumoniae, combined with its significant anti-inflammatory properties, positions the NADES-based eutectogel as a promising multifunctional platform for buccal drug delivery, particularly for inflammatory conditions complicated by bacterial infections.

Assessment of Potential Toxicity of Hyaluronic Acid-Coated Magnetic Nanoparticles on Maize (Zea mays) at Early Development Stages

The effectiveness of iron oxide nanoparticles in enhancing crop plant development depends on their stabilization. In this study, the effect of hyaluronic acid (HA), used both as a stabilizer for iron oxide nanoparticles (HA-MNP) and independently, was evaluated in maize seedlings. Different concentrations of HA-MNP (0.625-7.5 mg/L) were tested alongside a 0.01% HA solution. Growth parameters, antioxidant enzyme activities (peroxidase and polyphenol oxidase), photosynthetic pigments (chlorophyll and carotenoids), phenolic content, and genotoxicity were analyzed. While HA alone led to slight decreases in seedling length, pigment content, and polyphenol levels compared to the control, it increased peroxidase activity and mitotic index. Lower concentrations of HA-MNP (below 2.5 mg/L) enhanced seedling growth, likely due to improved iron uptake, whereas higher concentrations reduced pigment and phenolic content. All HA-MNP concentrations induced genotoxic effects, which was proven by an increased mitotic index and chromosomal aberrations, indicating both positive and defensive plant responses to oxidative stress. These findings suggest a complex interaction between HA, HA-MNP, and maize seedlings, where HA concentrations play a significant role in modulating growth and stress response, while higher concentrations may induce toxicity.

Temporal changes in parameters associated with tear film stability after instillation of long-acting diquafosol ophthalmic solution in soft contact lens wearers

PURPOSE

To investigate temporal changes in parameters associated with tear film stability after instillation of long-acting 3% diquafosol ophthalmic solution (DQS LX), which contains polyvinylpyrrolidone.

STUDY DESIGN

Prospective crossover study design.

METHODS

We enrolled 23 eyes of 23 soft contact lens (SCL) wearers (aged 25.3 ± 4.4 years). One-day disposable silicone hydrogel lenses (narafilcon A) were used in this study. DQS LX was instilled without a SCL on the first day. On the other two days, subjects received DQS or DQS LX at 7 h after wearing SCLs. Tear meniscus height (TMH), non-invasive tear break-up time (NIBUT) and ocular surface temperature (OST) were measured before and at 5, 15, 30, 45, 60, 80 and 120 min after instillation.

RESULTS

When not wearing SCLs, DQS LX instillation significantly improved TMH for up to 120 min and NIBUT for up to 80 min. When wearing SCLs, DQS and DQS LX instillation significantly increased TMH for up to 45 and 80 min, and NIBUT for up to 15 and 30 min. Compared to DQS, DQS LX administration resulted in a significantly higher TMH at 5, 60 and 80 min, as well as a significantly prolonged NIBUT at 5 and 60 min. OST with and without SCLs also varied depending on the changes in the parameters associated with tear film stability.

CONCLUSION

Compared to DQS, when wearing SCLs, DQS LX was found to increase the amount of tear fluid and improve tear film stability for longer periods.

Regulating cellular metabolism and morphology to achieve high-yield synthesis of hyaluronan with controllable molecular weights

High-yield biosynthesis of hyaluronan (HA) with controllable molecular weights (MWs) remains challenging due to the poorly understood function of Class I HA synthase (HAS) and the metabolic imbalance between HA biosynthesis and cellular growth. Here, we systematically characterize HAS to identify crucial regions involved in HA polymerization, secretion, and MW control. We construct HAS mutants that achieve complete HA secretion and expand the MW range from 300 to 1400 kDa. By dynamically regulating UDP-glucose 6-dehydrogenase activity and applying an adaptive evolution approach, we recover cell normal growth with increased metabolic capacities. Final titers and productivities for high MW HA (500 kDa) and low MW HA (10 kDa) reach 45 g L-1 and 105 g L-1, 0.94 g L-1 h-1 and 1.46 g L-1 h-1, respectively. Our findings advance our understanding of HAS function and the interplay between cell metabolism and morphology, and provide a shape-guided engineering strategy to optimize microbial cell factories.

In Vitro Evaluation and Clinical Effects of a Regenerative Complex with Non-Cross-Linked Hyaluronic Acid and a High-Molecular-Weight Polynucleotide for Periorbital Treatment

Skin aging is a complex and multifactorial process influenced by both intrinsic and extrinsic factors. The periorbital area of the face is particularly susceptible to premature aging signs due to its delicate skin structure, and is a major concern for many individuals. While hyaluronic acid (HA)-based dermal filler products are commonly used for periorbital rejuvenation, novel approaches to effectively locally address the visible signs of aging are available. This study aimed to investigate Innovyal Regenerative Action (IRA), an injectable polynucleotide-HA (PN-HA) regenerative complex designed for periocular prejuvenation. Firstly, PN-HA was compared to other commercially available HA-based dermbooster products (Profhilo®, Suisselle Cellbooster® Glow, and NCTF® 135 HA) in terms of rheological properties, in vitro antioxidant capacity, and total collagen production stimulation in human fibroblasts. Secondly, the clinical effects of the IRA PN-HA complex were evaluated in two case reports (monotherapy for periorbital prejuvenation). It was shown that the PN-HA complex outperformed its comparators in terms of relative rheological behavior (biophysical attributes normalized to polymer contents), intrinsic antioxidant activity (CUPRAC, FRAP, and ORAC assays), as well as total collagen level induction (72-h in vitro dermal fibroblast induction model). Generally, the results of this study provided mechanistic and preliminary clinical insights into the potential benefits of the IRA PN-HA complex for periocular cutaneous treatment. Overall, it was underscored that combining the structural support and regenerative properties of PN with the hydrating and volumizing effects of HA bares tangible potential for multifactorial skin quality enhancement and for periocular prejuvenation in particular.

The Effect of Alginate/Hyaluronic Acid Proportion on Semi-Interpenetrating Hydrogel Properties for Articular Cartilage Tissue Engineering

One of the emergent regenerative treatments for the restoration of the articular cartilage is tissue engineering (TE), in which hydrogels can functionally imitate the extracellular matrix (ECM) of the native tissue and create an optimal microenvironment for the restoration of the defective tissue. Hyaluronic acid (HA) is known for its potential in the field of TE as a regenerative material for many tissues. It is one of the major components of the articular cartilage ECM contributing to cell proliferation and migration. HA is the only non-sulphated glycosaminoglycan (GAG). However, herein, we use a HA presenting a high amount of sulphated glycosaminoglycans (sGAGs), altering the intrinsic properties of the material particularly in terms of biological response. Alginate (Alg) is another polysaccharide widely used in TE that allows stiff and stable hydrogels to be obtained when crosslinked with CaCl2. Taking the benefit of the favourable characteristics of each biomaterial, semi-interpenetrating (semi-IPN) hydrogels had been developed by the combination of both materials, in which alginate is gelled, and HA remains uncrosslinked within the hydrogel. Varying the concentration of alginate and HA, the final rheological, viscoelastic, and mechanical properties of the hydrogel can be tailored, always seeking a trade-off between biological and physico-mechanical properties. All developed semi-IPN hydrogels have great potential for biomedical applications.

Molecular Dynamics Simulation of Structural Assembly and Hydration of Hyaluronic Acid in Salt Aqueous Buffer

Hyaluronic acid (HA) is a nonsulfonated glycosaminoglycan critical in tissue development, physiology, and disease processes. To develop biomimetic in vitro models based on HA, it is important to understand the interaction of this polymer in its pristine form and with physiological solvents. However, atomistic simulations of HA chains are computationally challenging, especially when studying interactions with salts. To tackle this challenge, this study combined quantum mechanical (QM) calculations and molecular dynamics (MD) simulations to investigate HA's structure and behavior. This multiscale approach balances accuracy and computational efficiency. QM calculations emphasize the role of weak noncovalent hydrogen bonds in stabilizing d-glucuronic acid with N-acetyl-d-glucosamine. MD results show that more HA layers lead to a larger structure, higher water sensitivity, and increased dynamic and interlayer complexity. Our QM and MD simulations shed light on the structural dynamics and interactions of HA polymers and HA hydrogels, aiding in their design and optimization for biomedical applications and bridging computational and experimental approaches.

Investigation on the heating effects of intra-tumoral injectable magnetic hydrogels (IT-MG) for cancer hyperthermia

Capacitive-based radiofrequency (Rf) radiation at 27 MHz offers a non-invasive approach for inducing hyperthermia, making it a promising technique for thermal cancer therapy applications. To achieve focused and site-specific hyperthermia, Rf-responsive materials is required to convert Rf radiation into localized heat efficiently. Nanoparticles capable of absorbing Rf energy and convert into heat for targeted ablation are of critical importance. In this study, we developed and evaluated an Intra-tumoral injectable magnetic hydrogel (IT-MG) composed of Superparamagnetic Iron Oxide Nanoparticles (SPIONs) impregnated in low molecular weight Hyaluronic Acid (HA) forming HA-SPIONs. Our systematic investigation revealed that HA-SPIONs exposed to Rf radiation significantly increased temperature, reaching up to 50 °C. Further testing in tissue-mimicking phantom models also showed consistent heating, with temperatures stabilizing at 43 °C, ideal for localized hyperthermia. The ability of HA-SPIONs to act as an effective localized heating agent when exposed to 27 MHz Rf radiation, reaching apoptosis-inducing temperature, has not been previously reported. In conclusion, synergistic effects of IT-MG in bothin-vitroand tumor-mimicking phantom models demonstrate improved and localized hyperthermia, facilitating adjuvant cancer treatment.

Hyaluronic Acid-Coated SPIONs with Attached Folic Acid as Potential T2 MRI Contrasts for Anticancer Therapies

Superparamagnetic iron oxide nanoparticles (SPIONs) are known to be good MRI contrasts, but they have a high tendency to aggregate and their biocompatibility is limited. Hyaluronic acid is highly biocompatible, can provide SPION with colloidal stability, and interacts specifically with tumor cells through the CD44 receptor; therefore, it was used as a stabilizing layer. We successfully obtained SPION coated with hyaluronic acid and further functionalized it with folic acid to construct a dual-targeted system. The physicochemical properties of the nanoparticles were investigated using DLS/ELS, AFM, XRD, and ATR-FTIR. Their magnetic characterization was performed by magnetometry, Mössbauer spectroscopy, 1H NMR T1 and T2 measurements, and MRI. The nanoparticles' biocompatibility was verified on blood and hepatocytes, and their cytotoxicity was tested on glioma and adenocarcinoma cells using the MTT assay. The nanoparticles were spherical, colloidally stable, and had low dispersity. Their cores were formed by 7 nm crystallites of magnetite in its oxidized form, maghemite. Our SPIONs were superparamagnetic and could potentially serve as effective T2 contrasts for MRI. The performance of SPIONs modified with folic acid was superior to that observed for commercial contrasts. Our nanoparticles were also hemocompatible and were efficiently taken up by glioblastoma cancer cells. Folic acid-modified SPIONs could also reduce viability of tumor cells in a dose-dependent manner. Thus, the proposed system has potential application as both a diagnostic tool and a therapeutic agent for targeted anticancer therapies.

Mussel-Inspired Hydrogels Incorporating Graphite Derivatives for Soft Tissue Regeneration

Hyaluronic acid (HA)-based hydrogels offer a promising approach for soft tissue application due to their biocompatibility, tunable mechanical properties, ability to mimic the extracellular matrix, and capacity to support cell adhesion and proliferation. In this work, bioadhesive composite hydrogels were developed by integrating graphite derivatives (EG) into a dopamine-modified HA matrix (HA-Cat), which enhances tissue adhesion through catechol groups that mimic mussel-inspired adhesion mechanisms. The EG was functionalized via 1,3-dipolar cycloaddition reaction (f-EG), that allowed the anchoring of silver nanoparticles (f-EG-Ag) and grafting of hydrocaffeic acid (f-EG-Cat) on the functionalized EG surfaces. The hydrogels were produced by oxidative crosslinking of HA-Cat under mild basic pH conditions using sodium periodate. Indirect in vitro assays using L929 fibroblast cells showed high biocompatibility and enhanced cell proliferation at optimized composite hydrogel concentrations. These findings suggest that composite hydrogels could find an application as bioactive, adhesive scaffolds for the regeneration of soft tissues, where they can facilitate localized agent delivery and integration with the host tissue.

Bioprinting-By-Design of Hydrogel-Based Biomaterials for In Situ Skin Tissue Engineering

Burns are one of the most common trauma injuries worldwide and have detrimental effects on the entire body. However, the current standard of care is autologous split thickness skin grafts (STSGs), which induces additional injuries to the patient. Therefore, the development of alternative treatments to replace traditional STSGs is critical, and bioprinting could be the future of burn care. Specifically, in situ bioprinting offers several advantages in clinical applications compared to conventional in vitro bioprinting, primarily due to its ability to deposit bioink directly onto the wound. This review provides an in-depth discussion of the aspects involved in in situ bioprinting for skin regeneration, including crosslinking mechanisms, properties of natural and synthetic hydrogel-based bioinks, various in situ bioprinting methods, and the clinical translation of in situ bioprinting. The current limitations of in situ bioprinting is the ideal combination of bioink and printing mechanism to allow multi-material dispensing or to produce well-orchestrated constructs in a timely manner in clinical settings. However, extensive ongoing research is focused on addressing these challenges, and they do not diminish the significant potential of in situ bioprinting for skin regeneration.

Monophasic hyaluronic acid-silica hybrid hydrogels for articular cartilage applications

Hyaluronic acid (HA), an FDA-approved natural polymer and important component of the extracellular matrix (ECM), has been widely used to develop hydrogels for cartilage regeneration. However, HA hydrogels often exhibit poor mechanical properties and unsuitable degradability, limiting their capability to support cell growth in cartilage. To overcome these challenges, this study modifies HA with a silica precursor and the coupling agent (3-Glycidyloxypropyl) trimethoxysilane (GPTMS) to develop a monophasic organic-inorganic hybrid HA-silica hydrogel. In this system, the inorganic silicate and organic HA components interpenetrate and bond covalently at the molecular level. The HA-silica hybrid hydrogel achieves a compressive modulus of 143 kPa at the highest GPTMS/HA molar ratio of 400. Additionally, in vitro cell studies show that these hybrid hydrogels have no cytotoxicity against MC3T3-E1 and ATDC-5 cells. Cell viability and morphology tests further confirm excellent cell adhesion on the hybrid scaffold. These results indicate that the developed HA-silica hybrid hydrogel is a suitable candidate for cartilage regeneration applications.

Revisiting hydrogen peroxide as radiosensitizer for solid tumor cells

BACKGROUND AND PURPOSE

Tumor hypoxia is the principal cause of clinical radioresistance. Despite its established role as radiosensitizer, hydrogen peroxide (H2O2) encounters clinical limitations due to stability and toxicity concerns. Recent advancements in drug delivery combine H2O2 with sodium hyaluronate (SH), enabling intratumoral administration of H2O2. This study investigates the radiomodulatory pathways of Kochi Oxydol-Radiation for Unresectable Carcinomas (KORTUC) (H2O2 + SH) under hypoxia.

MATERIALS AND METHODS

CT26 and 4T1 tumor cells were exposed to H2O2, SH and KORTUC under hypoxic conditions. Toxicity levels were determined using MTT and live-cell analysis. KORTUC's radiomodulatory properties were evaluated by colony formation assay and in spheroids. Reactive oxygen species (ROS) levels, DNA damage, apoptosis and ferroptosis were analyzed using flow cytometry. Oxygen consumption rate (OCR) and mitochondrial complex activity were assessed by Seahorse Analyzer. Oxygen levels were investigated using fiber-optic sensors. The in vitro findings were validated in CT26-bearing mice.

RESULTS

KORTUC demonstrated less cytotoxicity than H2O2-alone. KORTUC radiosensitized hypoxic tumor cells in a dose-dependent manner with enhancement ratios of 3.1 (CT26) and 2.7 (4T1). Dose-dependent OCR reduction following KORTUC exposure correlated with complex I and II inhibition, accompanied by mitochondrial ROS elevation. KORTUC injection into a 2D hypoxic tumor model surged O2 levels. KORTUC radiosensitized CT26-tumors, delaying growth by 14 days.

CONCLUSIONS

SH in KORTUC mitigates H2O2 cytotoxicity. We demonstrate that KORTUC overcomes hypoxia-induced radioresistance through inhibition of OCR, via complex I- and II-blockade, leading to tumor reoxygenation. Understanding KORTUC's pathways is essential for developing effective cancer combination therapies.

Identification of CD44 as a key engager to hyaluronic acid-rich extracellular matrices for cell traction force generation and tumor invasion in 3D

Mechanical properties of the extracellular matrix (ECM) critically regulate a number of important cell functions including growth, differentiation and migration. Type I collagen and glycosaminoglycans (GAGs) are two primary components of ECMs that contribute to mammalian tissue mechanics, with the collagen fiber network sustaining tension, and GAGs withstanding compression. The architecture and stiffness of the collagen network are known to be important for cell-ECM mechanical interactions via cell surface adhesion receptor integrin. In contrast, studies of GAGs in modulating cell-ECM interactions are limited. Here, we present experimental studies on the roles of hyaluronic acid (HA) in single tumor cell traction force generation using a recently developed 3D cell traction force microscopy method. Our work reveals that CD44, a cell surface receptor to HA, is engaged in cell traction force generation in conjunction with β1-integrin. We find that HA significantly modifies the architecture and mechanics of the collagen fiber network, decreasing tumor cells' propensity to remodel the collagen network, attenuating traction force generation, transmission distance, and tumor invasion. Our findings point to a novel role for CD44 in traction force generation, which can be a potential therapeutic target for diseases involving HA rich ECMs such as breast cancer and glioblastoma.

Fabrication and Evaluation of Dissolving Hyaluronic Acid Microneedle Patches for Minimally Invasive Transdermal Drug Delivery by Nanoimprinting

Transdermal drug delivery minimizes pain and provides a controlled, stable release of drugs, but its effectiveness is limited by the skin's natural barriers. Microneedles overcome this problem, enabling minimally invasive drug delivery. Microneedle patches (MNPs) with 80 µm-tall needles composed of hyaluronic acid (HA) were developed and evaluated for their formability, structural integrity, dissolution rate, skin penetration ability, and drug transmission capacity. The influence of the molecular weight of HA on these properties was also investigated. MNPs made from low-molecular-weight HA (30 kDa-50 kDa) demonstrated 12.5 times superior drug permeability in ex vivo human skin compared to needleless patches (NLPs). Furthermore, in the same test, low-molecular-weight HA MNPs had 1.7 times higher drug permeability than high-molecular-weight HA MNPs, suggesting superior transdermal administration. The molecular weight of HA significantly influenced its solubility and permeability, highlighting the potential effectiveness of MNPs as drug delivery systems. Puncture tests demonstrated a penetration depth of 50-60 µm, indicating minimal nerve irritation in the dermis and effective drug delivery to the superficial dermal layer. These results present a manufacturing technique for MNPs incorporating model drug compounds and highlight their potential as a novel and minimally invasive drug delivery method for the biomedical applications of soft gels.

Injectable Hydrogels for Liver: Potential for Clinical Translation

Injectable hydrogels are a sub-type of hydrogels which can be delivered into the host in a minimally invasive manner. They can act as carriers to encapsulate and deliver cells, drugs or active biomolecules across several disease conditions. Polymers, either synthetic or natural, or even a combination of the two, can be used to create injectable hydrogels. Clinically approved injectable hydrogels are being used as dressings for burn wounds, bone and cartilage reconstruction. Injectable hydrogels have recently gained tremendous attention for their delivery into the liver in pre-clinical models. However, their efficacy in clinical studies remains yet to be established. In this article, we describe principles for the design of these injectable hydrogels, delivery strategies and their potential applications in facilitating liver regeneration and ameliorating injury. We also discuss the several constraints related to translation of these hydrogels into clinical settings for liver diseases and deliberate some potential solutions to combat these challenges.

Development and Characterization of Hyaluronic Acid Graft-Modified Polydopamine Nanoparticles for Antibacterial Studies

The problem of antibiotic abuse and drug resistance is becoming increasingly serious. In recent years, polydopamine (PDA) nanoparticles have been recognized as a potential antimicrobial material for photothermal therapy (PTT) due to their excellent photothermal conversion efficiency and unique antimicrobial ability. PDA is capable of rapidly converting light energy into heat energy under near-infrared (NIR) light irradiation to kill bacteria efficiently. In order to solve the problem of PDA's tendency to aggregate and precipitate, this study improved its stability by grafting hyaluronic acid (HA) onto the surface of PDA. Using dopamine and hyaluronic acid as raw materials, hyaluronic acid (HA) was grafted onto polydopamine (PDA) nanoparticles via self-polymerization and Michael addition reactions under alkaline conditions to obtain PDA-HA-modified nanoparticles. We confirmed the successful grafting of hyaluronic acid via scanning electron microscopy (SEM), Fourier infrared spectroscopy (FTIR), nuclear magnetic hydrogen spectroscopy (¹H NMR), ultraviolet-visible spectroscopy (UV-vis), Raman spectroscopy (Raman), and dynamic light scattering (DLS) methods. Scanning electron microscopy (SEM) was used to observe the surface morphology and nanostructure of the grafted materials, providing information on the morphology and size distribution of the materials. Near-infrared performance experiments showed that the temperature of the PDA-HA solution increased rapidly under near-infrared light irradiation, demonstrating an excellent photothermal conversion performance. Antimicrobial properties were assessed via the colony counting method, and typical Gram-positive bacteria S. aureus and Gram-negative bacteria E. coli were selected as model strains. The experimental groups were tested under dark conditions and near-infrared (NIR) light irradiation. PDA/HA showed significant photothermal properties under NIR light irradiation, resulting in a rapid increase in the surrounding temperature to a level sufficient to kill bacteria. Under NIR light irradiation, PDA/HA exhibited 100% antimicrobial efficacy against both S. aureus and E. coli, while antimicrobial efficacy was limited under dark conditions. This indicates that the antibacterial activity of PDA/HA is highly dependent on NIR light activation.

Hyaluronic Acid-Based Hybrid Nanoparticles as Promising Carriers for the Intranasal Administration of Dimethyl Fumarate

Purpose

Dimethyl fumarate (DMF), the first-line oral therapy for relapsing-remitting multiple sclerosis, is rapidly metabolized into monomethyl fumarate. The DMF oral administration provokes gastrointestinal discomfort causing treatment withdrawal. The present study aimed to develop an innovative formulation for DMF nasal administration. Lipid-polymer hybrid nanoparticles (LPNs) were developed to improve DMF stability, limiting gastrointestinal side effects and increasing brain bioavailability by nose-to-brain targeting application.

Methods

DMF-loaded and unloaded LPNs with or without hyaluronic acid (HA) were prepared using the nanoprecipitation via magnetic/mechanical stirring technique. Particle morphology and surface properties were evaluated; drug content, viscosity, and mucoadhesion were determined. Physico-chemical stability of LPNs and DMF in the LPNs was also explored. In vitro DMF permeation experiments were performed utilizing the PermeaPad®. The cytotoxicity and cellular uptake studies were performed using RPMI 2650 and SK-N-BE2 cell lines. DMF nose-to-brain delivery was evaluated by intranasally administering DMF-loaded LPNs to rats.

Results

LPNs with average sizes of 120-250 nm and a negative zeta potential -17.3 to -43 mV were obtained, primarily influenced by the presence of HA. HA assured drug stability up to 60 days and promoting the in vitro permeation of DMF compared to the free-DMF. HA greatly improved the viscosity and mucoadhesive properties. LPNs with and without HA did not exhibit any cytotoxicity and showed a rapid cell uptake starting from 15 min to 2 h with a best internalization after 1 h of treatment in both epithelial and neuronal cell lines. Nasal administration of DMF-loaded LPNs allowed to quantify up to about 12 μg/mL of DMF in the rat cerebrospinal fluid.

Conclusion

The results highlight the role of HA in improving LPNs properties and performance as carrier of DMF for nasal administration. In particular, LPNs appear able to enter neurons and monolayers of epithelial cells, allowing to promote the nose-to-brain DMF delivery.

Enhancing apple postharvest protection: Efficacy of pectin coatings containing Cryptococcus laurentii against Penicillium expansum

The aim of this work is the application of pectin coatings containing Cryptococcus laurentii as a method of biocontrol of Penicillium expansum for postharvest protection of apples. For this purpose, the yeast was incorporated into a pectin matrix, and its viability and biocontrol activity in vitro and in vivo against P. expansum was evaluated over time. In addition, the influence of the sterilization process on coating thickness was studied. Results showed that pectin coating with C. laurentii enhanced mycelial growth inhibition in vitro studies, while no significant differences were observed in disease incidence and severity reduction in vivo studies. The sterilization process reduced the viscosity of the pectin solution, resulting in coating thicknesses ranging from 0.5 to 1 μm. As a general evaluation, in vitro and in vivo, biocontrol assays were useful in demonstrating better postharvest protection of the yeast at 7 °C concerning 25 °C.

Viscocohesive hyaluronan gel enhances stability of intravital multiphoton imaging with subcellular resolution

Multiphoton microscopy (MPM) has become a preferred technique for intravital imaging deep in living tissues with subcellular detail, where resolution and working depths are typically optimized utilizing high numerical aperture, water-immersion objectives with long focusing distances. However, this approach requires the maintenance of water between the specimen and the objective lens, which can be challenging or impossible for many intravital preparations with complex tissues and spatial arrangements. We introduce the novel use of cohesive hyaluronan gel (HG) as an immersion medium that can be used in place of water within existing optical setups to enable multiphoton imaging with equivalent quality and far superior stability. We characterize and compare imaging performance, longevity, and feasibility of preparations in various configurations. This combination of HG with MPM is highly accessible and opens the doors to new intravital imaging applications.

Effectiveness of ultrasound-guided hip injections on pain and functioning in patients with hip osteoarthritis: A systematic review

BACKGROUND

Osteoarthritis is the most common form of arthritis, causing pain, functional disability, and a reduction in terms of quality of life. Minimally invasive treatments like intra-articular hip injections are a therapeutic option and ultrasound guidance might improve the results of these injections.

OBJECTIVE

To summarize the evidence about the effectiveness of ultrasound-guided hip injections in terms of pain and functioning in patients affected by hip osteoarthritis.

METHODS

A systematic search of the literature was performed on three electronic databases: PubMed, Cochrane and PEDro, using a specific search strategy. We evaluated for inclusion all articles according to the following participants, intervention, comparison, and outcomes (PICO) model: P) Population: human patients affected by hip osteoarthritis; I) Intervention: intra-articular hip injections performed with a ultrasound-guidance; C) Comparator: sham therapy or every other conservative or oral, non-invasive, minimally invasive or surgical technique; O) Outcome measures: pain assessed by Visual Analogue Scale (VAS) or Numerical Rating Scale (NRS); functional outcomes.

RESULTS

At the end of the search, 43 articles were included in the review. Several drugs have been considered in the included studies: hyaluronic acid, platelet-rich plasma, corticosteroids, micro-fragmented adipose tissue, bone marrow concentrates, amniotic suspension allograft.

CONCLUSION

Ultrasound-guided injections of hyaluronic acid might be effective on pain relief and functioning in patients affected by hip osteoarthritis. Also, other rehabilitative infiltrative techniques (i.e., corticosteroids and platelet-rich plasma) showed a positive effect in the short-term period.

The Effects of Synthetic Polymers on the Release Patterns of Bupivacaine Hydrochloride from Sodium Hyaluronate Hydrogels

BACKGROUND

Using hydrogels for the controlled release of drugs is beneficial for patients, who then receive the proper dose of the medicinal substance. In addition, the formulation can provide more consistent drug absorption while reducing the frequency of dosing.

OBJECTIVES

The aim of this investigation is to propose a novel HA (sodium hyaluronate)-based hydrogel for intra-articular injection doped with synthetic polymers and incorporated with bupivacaine hydrochloride (Bu) as a local anesthetic. The other aim of this study is to reveal the effects of the formulation's ingredients on its viscosity and the relationship between the hydrogel's viscosity and drug release.

METHODS

First, HA-based hydrogels doped with synthetic polymers and incorporated with Bu were prepared. A study of the hydrogels' viscosities was performed using a rotational viscometer. Release tests were carried out by employing a paddle-over-disk apparatus following the USP/Ph.Eur guidelines. The drug concentrations in the acceptor fluid were analyzed spectrophotometrically.

RESULTS

It was found that the viscosity of the hydrogels doped with synthetic polymers was higher than the viscosity of the hydrogels made with only HA. The viscosity of the hydrogels doped with AX (ammonium acryloyldimethyltaurate/VP copolymer) was the highest, measuring 6750 ± 160 cP and 12623 ± 379 cP with and without Bu, respectively. The results of the kinetic experiment indicate that the Higuchi and Korsmeyer-Peppas models best described the drug release. Bu was released the most slowly from the formulation doped with AX. The release rate constants obtained from the Higuchi and Korsmeyer-Peppas models were kH = 4.4 ± 0.2 mg × min-1/2 and kK-P = 3.4 ± 0.2 × 10-2 min-N, respectively. The half-release time, calculated using the Higuchi model, was the longest for the formulation doped with AX, at 199.5 ± 17.6 min.

CONCLUSIONS

This indicates that the incorporation of AX into the hydrogel may prolong the drug dissolution. The hydrogel doped with AX was the optimal formulation for the controlled release of Bu.

RNA Sequencing Revealed a Weak Response of Gingival Fibroblasts Exposed to Hyaluronic Acid

Hyaluronic acid was proposed to support soft tissue recession surgery and guided tissue regeneration. The molecular mechanisms through which hyaluronic acid modulates the response of connective tissue cells remain elusive. To elucidate the impact of hyaluronic acid on the connective tissue cells, we used bulk RNA sequencing to determine the changes in the genetic signature of gingival fibroblasts exposed to 1.6% cross-linked hyaluronic acid and 0.2% natural hyaluronic acid. Transcriptome-wide changes were modest. Even when implementing a minimum of 1.5 log2 fold-change and a significance threshold of 1.0 -log10, only a dozenth of genes were differentially expressed. Upregulated genes were PLK3, SLC16A6, IL6, HBEGF, DGKE, DUSP4, PTGS2, FOXC2, ATAD2B, NFATC2, and downregulated genes were MMP24 and PLXNA2. RT-PCR analysis supported the impact of hyaluronic acid on increasing the expression of a selected gene panel. The findings from bulk RNA sequencing suggest that gingival fibroblasts experience weak changes in their transcriptome when exposed to hyaluronic acid.

Range of Flexion Improvement in Degenerative Stages of the First Metatarsophalangeal Joint (Hallux rigidus) with Cross-Linked Hyaluronic Acid: A Cadaveric Study

BACKGROUND

Viscosupplementation consists of intraarticular hyaluronic acid injections applied to treat pain and improve joint mobility. The objective of the study was to analyze the improvement of the range of mobility of the first metatarsophalangeal joint with a single dose of cross-linked hyaluronic acid.

METHODS

Ten fresh frozen specimens of feet sectioned below the knee were selected. Before and after the infiltration procedure, the range of flexion was calculated for all specimen's metatarsophalangeal joints. To detect complications due to the procedure, five feet were dissected and five were sectioned with a diamond saw.

RESULTS

The range of the first metatarsophalangeal joint flexion differences between the preoperative and the postoperative period was as follows: (1) 47° (range, 37-51.5) to 58° (range, 49-69.5) degrees of loaded dorsiflexion (p > 0.006); (2) 41° (range, 40-51.5) to 58° (range, 52.5-66.5) degrees of unloaded dorsiflexion (p > 0.009); and (3) 14° (range, 10.5-24.25) to 16° (range, 14.25-28.5) degrees of unloaded plantarflexion (p > 0.083). No injuries of anatomical structures were observed either by anatomical dissection or in the anatomical sections.

CONCLUSIONS

The results obtained in this viscosupplementation study demonstrate the improvement of the range of mobility of the first metatarsophalangeal joint without evidence of extravasation and lesions of the periarticular anatomical structures.

Synthesis and Engineering of Hyaluronic Acid-Gelatin Hydrogels with Improved Cellular Attachment and Growth

Injectable hydrogels are promising materials for cartilage regeneration in tissue engineering due to their tunable crosslinking rates, mechanical properties, and biodegradation profiles. This study investigates the chondrogenic potential of hyaluronic acid (HA) hydrogels crosslinked via tyramine (TA) moieties, with and without gelatin modified with TA (Gel-TA). Incorporating Gel-TA improved cell viability, spreading, and cartilage matrix deposition, particularly in medium and high molecular weight (MMW and HMW) HA-TA/Gel-TA hydrogels. Although the hydrogels' molecular weight did not significantly alter stiffness, MMW and HMW HA-TA/Gel-TA formulations exhibited enhanced functional properties such as slower degradation and superior cartilage matrix deposition. These attributes, coupled with Gel-TA's effects, underscore the importance of both molecular weight and biofunctional components in hydrogel design for cartilage regeneration. While low molecular weight (LMW) HA-TA hydrogels offered excellent injectability and supported high cell viability, they degraded rapidly and exhibited reduced cartilage matrix formation. Gel-TA enhanced cell adhesion and spreading by providing integrin-binding sites and promoted collagen type II deposition, crucial for cartilage regeneration. Moreover, the increased stiffness of MMW and HMW HA-TA/Gel-TA hydrogels facilitated extracellular matrix production. These findings show the potential of Gel-TA-modified HA-TA hydrogels for cartilage tissue engineering, with the opportunity for further optimization through the incorporation of bioactive components.

Extraction and Purification of Biopolymers from Marine Origin Sources Envisaging Their Use for Biotechnological Applications

Biopolymers are a versatile and diverse class of materials that has won high interest due to their potential application in several sectors of the economy, such as cosmetics, medical materials/devices, and food additives. In the last years, the search for these compounds has explored a wider range of marine organisms that have proven to be a great alternative to mammal sources for these applications and benefit from their biological properties, such as low antigenicity, biocompatibility, and biodegradability, among others. Furthermore, to ensure the sustainable exploitation of natural marine resources and address the challenges of 3R's policies, there is a current necessity to valorize the residues and by-products obtained from food processing to benefit both economic and environmental interests. Many extraction methodologies have received significant attention for the obtention of diverse polysaccharides, proteins, and glycosaminoglycans to accomplish the increasing demands for these products. The present review gives emphasis to the ones that can be obtained from marine biological resources, as agar/agarose, alginate and sulfated polysaccharides from seaweeds, chitin/chitosan from crustaceans from crustaceans, collagen, and some glycosaminoglycans such as chondroitin sulfate and hyaluronic acids from fish. It is offered, in a summarized and easy-to-interpret arrangement, the most well-established extraction and purification methodologies used for obtaining the referred marine biopolymers, their chemical structure, as well as the characterization tools that are required to validate the extracted material and respective features. As supplementary material, a practical guide with the step-by-step isolation protocol, together with the various materials, reagents, and equipment, needed for each extraction is also delivered is also delivered. Finally, some remarks are made on the needs still observed, despite all the past efforts, to improve the current extraction and purification procedures to achieve more efficient and green methodologies with higher yields, less time-consuming, and decreased batch-to-batch variability.

Marine polysaccharides for antibiofilm application: A focus on biomedical fields

Microbial pathogens such as bacteria and fungi form biofilms, which represent substantial hurdles in treating human illness owing to their adaptive resistance mechanism to conventional antibiotics. Biofilm may cause persistent infection in a variety of bodily areas, including wounds, oral cavity, and vaginal canal. Using invasive devices such as implants and catheters contributes significantly to developing healthcare-associated infections because they offer an ideal surface for biofilm formation. Marine organisms produce a variety of polysaccharides, which have recently attracted worldwide attention due to their biochemical features, various applications, and advantageous properties such as bioactivity, biodegradability, and biocompatibility. Because of their antimicrobial and antibiofilm features, several polysaccharides such as chitosan, fucoidan, carrageenan, alginate, and hyaluronic acid have been used to treat infected wounds as well as ophthalmic, oral, and vaginal infections. In addition, marine polysaccharides are currently employed as coatings on medical devices and implant materials, alone or in combination with other bioactive substances or nanomaterials, to protect the materials' undertones from microbial contamination. This review discussed the recent advancements in marine polysaccharides and their derivatives as a therapeutic potential against biofilm-associated diseases. The potential obstacles in the scalability of their production, clinical translation, and/or regulatory hurdles have also been discussed.

Recent advances in polysaccharide-based drug delivery systems for cancer therapy: a comprehensive review

Cancer has a high rate of incidence and mortality throughout the world. Although several conventional approaches have been developed for the treatment of cancer, such as surgery, chemotherapy, radiotherapy and thermal therapy, they have remarkable disadvantages which result in inefficient treatment of cancer. For example, immunogenicity, prolonged treatment, non-specificity, metastasis and high cost of treatment, are considered as the major drawbacks of chemotherapy. Therefore, there is a fundamental requirement for the development of breakthrough technologies for cancer suppression. Polysaccharide-based drug delivery systems (DDSs) are the most reliable drug carriers for cancer therapy. Polysaccharides, as a kind of practical biomaterials, are divided into several types, including chitosan, alginates, dextran, hyaluronic acid, cyclodextrin, pectin, etc. Polysaccharides are extracted from different natural resources (like herbal, marine, microorganisms, etc.). The potential features of polysaccharides have made them reliable candidates for therapeutics delivery to cancer sites; the simple purification, ease of modification and functionalization, hydrophilicity, serum stability, appropriate drug loading capacity, biocompatibility, bioavailability, biodegradability and stimuli-responsive and sustained drug release manner are considerable aspects of these biopolymers. This review highlights the practical applications of polysaccharides-based DDSs in pharmaceutical science and cancer therapy.

Development of Dispersion Process to Improve Quality of Hyaluronic Acid Filler Crosslinked with 1,4-Butanediol Diglycidyl Ether

This study proposes a new and simple process that improves the quality of a hyaluronic acid (HA) filler crosslinked with 1,4-butanediol diglycidyl ether (BDDE) using solution dispersion at a low temperature. This process involves the solvent being dispersed among the solute naturally after the mixing process. The process used in this study involved two reactions. First, the solution was dispersed among HA molecules (Mw = ~0.7 MDa) creating a well-homogenized mixture. Second, the decomposition and synthesis of HA occurred naturally in an aqueous alkaline solution (>pH 11), the weight average molar mass (Mw) was adjusted (Mw = ~143,000), and the crosslinking surface area was expanded, allowing for a high degree of crosslinking. Therefore, the viscoelasticity and cohesion of the filler increased with the new method compared to the previous process both at the lab scale (previous process:new process, viscosity (cP) = 24M:43M, storage modulus (Pa) = 306:538, loss modulus (Pa) = 33:61, and tack (N) = 0.24:0.43) and at the factory scale (previous process:new process, complex viscosity (cP) = 19M:26M, storage modulus (Pa) = 229:314, loss modulus (Pa) = 71:107, and tack (N) = 0.35:0.43).

Amphotericin B Ocular Films for Fungal Keratitis and a Novel 3D-Printed Microfluidic Ocular Lens Infection Model

Fungal keratitis (FK), a severe eye infection that leads to vision impairment and blindness, poses a high risk to contact lens users, and Candida albicans remains the most common underpinning fungal pathogen in temperate climates. Patients are initially treated empirically (econazole 1% drops hourly for 24-48 h), and if there is no response, amphotericin B (AmB) 0.15% eye drops (extemporaneously manufactured to be stable for a week) are the gold-standard treatment. Here, we aim to develop a sustained-release AmB ocular film to treat FK with an enhanced corneal retention time. As there is a paucity of reliable in vitro models to evaluate ocular drug release and antifungal efficacy under flow, we developed a 3D-printed microfluidic device based on four chambers stacked in parallel, in which lenses previously inoculated with a C. albicans suspension were placed. Under the flow of a physiological fluid over 24 h, the release from the AmB-loaded film that was placed dry onto the surface of the wetted contact lenses was quantified, and their antifungal activity was assessed. AmB sodium deoxycholate micelle (dimeric form) was mixed with sodium alginate and hyaluronic acid (3:1 w/w) and cast into films (0.48 or 2.4%), which showed sustained release over 24 h and resulted in a 1.23-fold reduction and a 5.7-fold reduction in CFU/mL of C. albicans, respectively. This study demonstrates that the sustained delivery of dimeric AmB can be used for the treatment of FK and provides a facile in vitro microfluidic model for the development and testing of ophthalmic antimicrobial therapies.

Ultralow Power, Cleft Size-Adjustable and pH-Sensitive Hyaluronic Acid (HA) Biodevices for Acid-Sensing Ion Channels Emulation

The burgeoning implantable biodevices have unlocked new frontiers in healthcare, promising personalized monitoring strategies tailored to specific needs. Herein, hyaluronic acid (HA) is harnessed to create fully biocompatible, acidity-sensitivity and cleft-adjustable neuromorphic devices. These HA-biodevices exhibit remarkable sensitivity to pH variations, effectively mimicking biological acid-sensing ion channels (ASICs) through protonation reactions between electronegative atoms and hydrogen ions, even at ultralow driving voltage (5 mV). They can monitor joint cartilage acidity by tracking changes in proton concentration and successfully diagnose the onset of arthritis. Furthermore, by adjusting the synaptic device's cleft distance, which determines responsiveness, power efficiency and plasticity, HA-based neuromorphic devices can be tailored to meet the unique demands of various implantation sites, providing both high-sensitivity and low-heat dissipation, thus broadening their application scopes. Moreover, the HA-biodevices maintain stable performance across various bending degrees, up to a curvature radius of 7.5 mm, with flexibility and deformation resilience enabling installation on joints of varying curvatures. The combination of all-biocompatibility, high sensitivity, low heat dissipation, ultralow low power (2 pW), and extraordinary deformation tolerance paves the way for the development of versatile, multipurpose medical monitoring devices with immense potential in the field of healthcare.

Excipient-free nanotransformation of hydrophilic macromolecules using aqueous counter collision for enhanced bioavailability

The demand for sustainable, eco-friendly biopolymer transdermal delivery systems has increased owing to growing environmental awareness. In this study, we used aqueous counter collision (ACC), a nontoxic nanotransformation method, to convert high- and ultrahigh-molecular-weight hydrophilic macromolecules into their corresponding nanoparticles (NPs). Hyaluronic acid (HA) and crosslinked HA (CLHA) were chosen as the model compounds. Their NPs exhibited particle sizes in the range of 10-100 nm and negative zeta potentials (-20 to -30 mV). Transmission electron microscopy revealed that the NPs were nearly spherical with smooth surfaces. Fourier-transform infrared and proton nuclear magnetic resonance spectroscopy and agarose gel electrophoresis confirmed that the structures and molecular weights of HA and CLHA remained unaltered after ACC. However, the storage and loss moduli of HANPs and CLHANPs were significantly lower than those of HA and CLHA, respectively. Furthermore, the permeation of HANPs and CLHANPs in reconstructed human skin and human cadaver skin was visualized and quantified. HANPs and CLHANPs penetrated deeper into the skin, whereas HA and CLHA were mainly found in the stratum corneum. The total skin absorption (permeation and deposition) of HANPs and CLHANPs was approximately 2.952 and 5.572 times those of HA and CLHA, respectively. Furthermore, HANPs and CLHANPs exhibited resistance to enzyme and free radical degradation. Our findings reveal ACC as a promising, sustainable hydrophilic macromolecule delivery system compared with the chemical hydrolysis of HA.