Comparative in vitro study on cytotoxicity, antimicrobial activity, and binding capacity for pathophysiological factors in chronic wounds of alginate and silver-containing alginate

Defining wound bed conformability: a new testing methodology to assess the relative swelling rise of foam dressings

OBJECTIVE

Using a dressing that expands and conforms to the wound bed upon exudate absorption is one of the best ways to promote wound healing. While many products claim wound bed conformability, no externally replicated or verified test methodology had been developed to quantify a wound dressing's ability to conform to the wound bed. The Relative Swelling Rise (RSR) test methodology was developed to measure the relative swelling rise of foam dressings upon fluid absorption, and offers a quantifiable and easily replicated method to measure wound bed conformability.

METHOD

The RSR test method was developed, validated and reliability tested by Coloplast A/S, Denmark. External replication was provided by ALS Odense, Denmark (previously DB Lab). Circular fences provide a fixed diameter to apply and contain the fluid and prevent horizontal spreading in the test set-up. The swelling height is quantified relative to the fence's inner diameter, i.e., the ratio alpha (α), and allows evaluation of a material's ability to conform to the wound bed.

RESULTS

Biatain Silicone foam products (n=3, Coloplast A/S, Denmark) were tested, all afforded an average α-ratio from 0.30 to 0.60. The relative standard deviations were between 1-3%, demonstrating the strength of the test. Robustness of the methodology was demonstrated through the internal validation study, the reliability study, and both an internal and external replication study, as well as a systematic literature review and expert review of the construct, content, criterion and generalisability of the method.

CONCLUSION

Having a validated, effective and easily replicable testing method to quantify wound bed conformability of foam dressings is an important step towards achieving better healing outcomes.

Bioactive Dressing: A New Algorithm in Wound Healing

Wound management presents a significant global challenge, necessitating a comprehensive understanding of wound care products and clinical expertise in selecting dressings. Bioactive dressings (BD) represent a diverse category of dressings, capable of influencing wound healing through various mechanisms. These dressings, including honey, hyaluronic acid, collagen, alginates, and polymers enriched with polyhexamethylene biguanide, chitin, and chitosan derivatives, create a conducive environment for healing, promoting moisture balance, pH regulation, oxygen permeability, and fluid management. Interactive dressings further enhance targeted action by serving as substrates for bioactive agents. The continuous evolution of BDs, with new products introduced annually, underscores the need for updated knowledge in wound care. To facilitate dressing selection, a practical algorithm considers wound exudate, infection probability, and bleeding, guiding clinicians through the process. This algorithm aims to optimize wound care by ensuring the appropriate selection of BDs tailored to individual patient needs, ultimately improving outcomes in wound management.

A new dressing system for accelerating wound recovery after primary total knee arthroplasty: a feasibility study

PURPOSE

Currently, postoperative wound infection and poor healing of total knee arthroplasty have been perplexing both doctors and patients. We hereby innovatively invented a new dressing system to reduce the incidence of postoperative wound complications.

METHODS

We enrolled 100 patients who received primary unilateral total knee arthroplasty and then applied the new dressing system. The data collected included the number of dressing changes, postoperative hospital stay, Visual Analogue Scale score (VAS), the Knee Society Score (KSS), the Knee Injury and Osteoarthritis Outcome Score (KOOS), ASEPSIS scores, The Stony Brook Scar Evaluation Scale (SBSES), wound complications, dressing cost, the frequency of shower and satisfaction. Subsequently, a statistical analysis of the data was performed.

RESULTS

Our findings demonstrated the average number of postoperative dressing changes was 1.09 ± 0.38, and the average postoperative hospital stay was 3.72 ± 0.98 days. The average cost throughout a treatment cycle was 68.97 ± 12.54 US dollars. Collectively, the results of VAS, KSS, and KOOS revealed that the pain and function of patients were continuously improved. The results of the four indexes of the ASEPSIS score were 0, whereas the SBSES score was 3.58 ± 0.52 and 4.69 ± 0.46 at two weeks and one month after the operation, respectively. We observed no wound complications until one month after the operation. Remarkably, the satisfaction rate of the patients was 91.85 ± 4.99% one month after the operation.

CONCLUSION

In this study, we invented a new dressing system for surgical wounds after total knee arthroplasty and further confirmed its clinical feasibility and safety.

CHINESE CLINICAL TRIAL REGISTRY

ChiCTR2000033814, Registered 13/ June/2020.

3D Printing of Alginate/Chitosan-Based Scaffold Empowered by Tyrosol-Loaded Niosome for Wound Healing Applications: In Vitro and In Vivo Performances

This study introduces a tyrosol-loaded niosome integrated into a chitosan-alginate scaffold (Nio-Tyro@CS-AL), employing advanced electrospinning and 3D printing techniques for wound healing applications. The niosomes, measuring 185.40 ± 6.40 nm with a polydispersity index of 0.168 ± 0.012, encapsulated tyrosol with an efficiency of 77.54 ± 1.25%. The scaffold's microsized porous structure (600-900 μm) enhances water absorption, promoting cell adhesion, migration, and proliferation. Mechanical property assessments revealed the scaffold's enhanced resilience, with niosomes increasing the compressive strength, modulus, and strain to failure, indicative of its suitability for wound healing. Controlled tyrosol release was demonstrated in vitro, essential for therapeutic efficacy. The scaffold exhibited significant antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus, with substantial biofilm inhibition and downregulation of bacterial genes (ndvb and icab). A wound healing assay highlighted a notable increase in MMP-2 and MMP-9 mRNA expression and the wound closure area (69.35 ± 2.21%) in HFF cells treated with Nio-Tyro@CS-AL. In vivo studies in mice confirmed the scaffold's biocompatibility, showing no significant inflammatory response, hypertrophic scarring, or foreign body reaction. Histological evaluations revealed increased fibroblast and macrophage activity, enhanced re-epithelialization, and angiogenesis in wounds treated with Nio-Tyro@CS-AL, indicating effective tissue integration and repair. Overall, the Nio-Tyro@CS-AL scaffold presents a significant advancement in wound-healing materials, combining antibacterial properties with enhanced tissue regeneration, and holds promising potential for clinical applications in wound management.

A standardized wound infection model for antimicrobial testing of wound dressings in vitro

To investigate the effectiveness of antimicrobial agents against wound infections, experiments using either 2D cultures with planktonic microorganisms or animal infection models are frequently carried out. However, the transferability of the results to human skin is limited by the lack of complexity of the 2D models or by the poor translation of the results from animal models. Hence, there is a need for wound infection models capable of assessing antimicrobial agents. In this study, an easily standardized wound infection model was established. This model consists of a mechanically wounded human skin model on a collagen matrix infected with various clinically relevant bacteria. Infection of the model led to recognition of the pathogens and induction of an inflammatory response. The untreated infection spread over time, causing significant tissue damage. By applying an antimicrobial-releasing wound dressing, the bacterial load could be reduced and the success of the treatment could be further measured by a decrease in the inflammatory reaction. In conclusion, this wound infection model can be used to evaluate new antimicrobial therapeutics as well as to study host-pathogen interactions.

Effect of Spray-Type Alginate Hydrogel Dressing on Burn Wounds

Immediate burn wound care is a critical factor influencing the outcomes of burn treatment. In this study, we developed a spray-type alginate hydrogel dressing that promotes wound healing, reduces pain, and increases the convenience of use in a burn treatment emergency. We investigated the efficiency of newly developed spray-type alginate hydrogel dressing on the wound healing process. We investigated the efficacy of the alginate hydrogel dressing for wound healing in 30 Sprague Dawley rats. Four deep, round second-degree burn wounds (diameter, 1.5 cm) were created bilaterally on the dorsum of the rat's trunk; the rats were divided into four groups, in which different dressing materials were applied as follows: group A, gauze (control); group B, Mepilex™ (control); group C, 2.25% alginate hydrogel; and group D, 2.5% alginate hydrogel. The gross findings of each group were compared by tracing the remaining wound and performing visual and histological observations and biochemical analysis for proteins associated with wound healing at each time period. In burn wounds, groups C and D showed significantly higher contraction, epithelialization, and healing rates. Histologically, groups C and D showed an improved arrangement of collagen fibers and a thick epithelial layer 14 days after initial wound formation. Group C showed higher CD31, TGF-β, and fibronectin expression in Western blot analyses after day 14. This study suggests that the spray-type alginate hydrogel dressing is an effective material for initial burn wound care.

Functionally multifaceted alginate/curdlan/agarose-based bilayer fibro-porous dressings for addressing full-thickness diabetic wounds

Full-thickness diabetic wounds are chronic injuries characterized by bleeding, excessive exude, and prolonged inflammation. Single-layer dressings fail to address their disturbed pathophysiology. Therefore, bilayer dressings with structural and compositional differences in each layer have gained attention. We hypothesized that natural polymer (alginate, curdlan, and agarose) based bilayer dressings with inherent healing properties could effectively resolve these issues. Hence, bilayer dressings were fabricated by electrospinning curdlan/agarose/ polyvinyl alcohol blend (top layer) on an alginate/agarose/polyvinyl alcohol-based lyophilized porous (bottom) layer. Ciprofloxacin was incorporated in both layers as a potential antibacterial drug. The bilayer dressing exhibited high swelling (~1300 %), biocompatibility (>90 % with NIH 3T3 and L929 mouse fibroblasts), and hemocompatibility (hemolysis <5 %). In vitro, scratch assay revealed a faster wound closure (~ 95-100 %) than control. Inhibition zone assay revealed antibacterial activity against Staphylococcus aureus and Escherichia coli. Real-time (in vitro) gene expression experiments performed using human THP-1 macrophages exhibited a significant increase in anti-inflammatory cytokines (4.51 fold in IL-10) and a decrease in pro-inflammatory cytokines (1.42 fold in IL-6) in comparison to lipopolysaccharide. Thus, fabricated dressings with high swelling, hemostatic, immunomodulatory, and antibacterial characteristics can serve as potential multifunctional and sustainable templates for healing full-thickness diabetic wounds.

Alginate/gum arabic-based biomimetic hydrogel enriched with immobilized nerve growth factor and carnosine improves diabetic wound regeneration

Diabetic foot ulcers (DFUs) often remain untreated because they are difficult to heal, caused by reduced skin sensitivity and impaired blood vessel formation. In this study, we propose a novel approach to manage DFUs using a multifunctional hydrogel made from a combination of alginate and gum arabic. To enhance the healing properties of the hydrogel, we immobilized nerve growth factor (NGF), within specially designed mesoporous silica nanoparticles (MSN). The MSNs were then incorporated into the hydrogel along with carnosine (Car), which further improves the hydrogel's therapeutic properties. The hydrogel containing the immobilized NGF (SiNGF) could control the sustain release of NGF for >21 days, indicating that the target hydrogel (AG-Car/SiNGF) can serve as a suitable reservoir managing diabetic wound regeneration. In addition, Car was able to effectively reduce inflammation and significantly increase angiogenesis compared to the control group. Based on the histological results obtained from diabetic rats, the target hydrogel (AG-Car/SiNGF) reduced inflammation and improved re-epithelialization, angiogenesis, and collagen deposition. Specific staining also confirmed that AG-Car/SiNGF exhibited improved tissue neovascularization, transforming growth factor-beta (TGFβ) expression, and nerve neurofilament. Overall, our research suggests that this newly developed composite system holds promise as a potential treatment for non-healing diabetic wounds.

Can an Alginate-based Wound Dressing Modified with Garden Cress Substitute for COE-PAK as a Wound Dressing? An In Vitro Study

AIM

The aim of the current study was to prepare a natural oral wound dressing from alginate modified with garden cress (GC), a rich source of antibacterial phytochemical compounds essential for wound healing.

MATERIALS AND METHODS

Sodium alginate (SA) dressing (negative control group), was prepared and modified with GC seeds extracts (25 µg/mL and 50 µg/mL) as the intervention groups, and COE-PAK was the positive control group. Cytotoxicity was measured using WST-1 assay (n = 15) after 24 and 48 hours. The in vitro wound healing assay (n = 15) was assessed in terms of wound width, and cell migration rate (0, 24, 48, and 72 hours). Agar diffusion test was performed to investigate the antibacterial action (n = 15) of the groups against Streptococcus mutans and Lactobacillus casei strains. Results were significant at p ≤ 0.05.

RESULTS

There was no statistically significant difference in cytotoxicity in all groups (p = 0.24 at 24 hours and 0.1 at 48 hours). Garden cress-containing groups revealed the lowest mean value of wound width (0.27 mm ± 0.01 and 0.23 mm ± 0.01 for 25 µg/mL and 50 µg/mL, respectively at 48 hours) and the highest mean value of cell migration rate (0.013 mm/hour ± 0.004 and 0.014 mm/hour ± 0.004 for 25 µg/mL and 50 µg/mL, respectively at 48 hours), in addition to the highest antibacterial action (1.49 mm ± 0.05 and 2.14 mm ± 0.09 for 25 µg/mL and 50 µg/mL, respectively against S. mutans, 1.43 mm ± 0.07 and 2.55 mm ± 0.09 for 25 µg/mL and 50 µg/mL, respectively against L. casei).

CONCLUSION

Alginate wound dressing modified with GC extract could be considered a promising wound dressing material in terms of wound healing and antibacterial action.

CLINICAL SIGNIFICANCE

Ready-to-use alginate-based wound dressing modified with GC extract may represent a promising natural alternative to the most commonly used oral wound dressing (COE-PAK).

Tailoring the Swelling-Shrinkable Behavior of Hydrogels for Biomedical Applications

Hydrogels with tailor-made swelling-shrinkable properties have aroused considerable interest in numerous biomedical domains. For example, as swelling is a key issue for blood and wound extrudates absorption, the transference of nutrients and metabolites, as well as drug diffusion and release, hydrogels with high swelling capacity have been widely applicated in full-thickness skin wound healing and tissue regeneration, and drug delivery. Nevertheless, in the fields of tissue adhesives and internal soft-tissue wound healing, and bioelectronics, non-swelling hydrogels play very important functions owing to their stable macroscopic dimension and physical performance in physiological environment. Moreover, the negative swelling behavior (i.e., shrinkage) of hydrogels can be exploited to drive noninvasive wound closure, and achieve resolution enhancement of hydrogel scaffolds. In addition, it can help push out the entrapped drugs, thus promote drug release. However, there still has not been a general review of the constructions and biomedical applications of hydrogels from the viewpoint of swelling-shrinkable properties. Therefore, this review summarizes the tactics employed so far in tailoring the swelling-shrinkable properties of hydrogels and their biomedical applications. And a relatively comprehensive understanding of the current progress and future challenge of the hydrogels with different swelling-shrinkable features is provided for potential clinical translations.

Comparison of Biatain Ag and Biatain Alginate Ag dressings on skin graft donor sites: a prospective clinical trial

OBJECTIVE

The aim of this study was to compare Biatain Ag and Biatain Alginate Ag (both Coloplast, Denmark) as skin graft donor site dressings.

METHOD

A single-centre, prospective, randomised clinical study was conducted. In patients who had undergone a skin graft operation, adjacent split-thickness skin graft donor sites were dressed with Biatain Ag and Biatain Alginate Ag, respectively. The primary outcomes were time to re-epithelialisation and pain score after the operation. The secondary outcomes were scar scores of the donor site after the operation, haematoma rates, infection rates, and exudation rates before wound healing. Results were compared using the Wilcoxon test and the Chi-squared test.

RESULTS

A total of 16 paired wounds in 16 patients were studied. The donor sites dressed with Biatain Ag needed more time for >90% re-epithelialisation than those dressed with Biatain Alginate Ag. On day 3 postoperatively, the pain scores with Biatain Ag were significantly less severe than those with Biatain Alginate Ag. On days 6, 9 and 12, the pain scores of both dressings did not differ significantly. The scar scores of the donor site dressed with Biatain Ag were significantly worse than those dressed with Biatain Alginate Ag at 6 months. With respect to infection rates, no significant differences were detected between these two groups. However, the exudation rates of the donor site dressed with Biatain Ag were significantly lower than those dressed with Biatain Alginate Ag.

CONCLUSION

As skin graft donor site dressings, both Biatain Ag and Biatain Alginate Ag have advantages.

Topical Alginate Protection against Pepsin-Mediated Esophageal Damage: E-Cadherin Proteolysis and Matrix Metalloproteinase Induction

Epithelial barrier dysfunction is a hallmark of gastroesophageal reflux disease (GERD) related to symptom origination, inflammatory remodeling and carcinogenesis. Alginate-based antireflux medications were previously shown to topically protect against peptic barrier disruption, yet the molecular mechanisms of injury and protection were unclear. Herein, Barrett's esophageal (BAR-T) cells were pretreated with buffered saline (HBSS; control), dilute alginate medications (Gaviscon Advance or Gaviscon Double Action, Reckitt Benckiser), a viscosity-matched placebo, or ADAM10 and matrix metalloproteinase (MMP) inhibitors before exposure to HBSS pH7.4 or pH4 ± 1 mg/mL pepsin for 10-60 min. Cell viability was assessed by ATP assay; mediators of epithelial integrity, E-cadherin, ADAM10, and MMPs were examined by Western blot and qPCR. Alginate rescued peptic reduction of cell viability (p < 0.0001). Pepsin-pH4 yielded E-cadherin fragments indicative of regulated intramembrane proteolysis (RIP) which was not rescued by inhibitors of known E-cadherin sheddases. Transcriptional targets of E-cadherin RIP fragments were elevated at 24 h (MMP-1,2,9,14; p < 0.01). Alginate rescued E-cadherin cleavage, ADAM10 maturation, and MMP induction (p < 0.01). Results support RIP as a novel mechanism of peptic injury during GERD. Alginate residue after wash-out to mimic physiologic esophageal clearance conferred lasting protection against pepsin-induced molecular mechanisms that may exacerbate GERD severity and promote carcinogenesis in the context of weakly acidic reflux.

Multifunctional thermosensitive hydrogel based on alginate and P(NIPAM-co-HEMIN) composites for accelerated diabetic wound healing

Non-healing wounds in patients with diabetes are a concerning issue associated with amputation and a high mortality rate. These wounds are exacerbated by oxidative stress and microbial infections resulting from hyperglycemia. Therefore, advanced materials for repairing wound beds must be identified urgently. This paper introduces a topically applicable composite hydrogel with thermosensitive properties and presents the antibacterial and antioxidant activities in mice with diabetes-induced wounds. This composite is developed by combining poly N-isopropyl acrylamide (NIPAM)-copolymerized HEMIN (NIPAM-co-HEMIN) and amine-modified alginate (ALG-EDA) biomaterials, with Ag nanoparticles (AgNPs) incorporated into the system as an antibacterial agent. Results of antibacterial tests show that the p(NIPAM-co-HEMIN)/ALG-EDA/AgNP composite system is effective against E. coli and S. aureus. Additionally, the AgNP composite exhibits low cellular toxicity in NIH3T3 and CT-2A cell lines. The wounds in diabetic mice treated with the composite system healed in <12 days, and the composite system accelerated the healing process by increasing collagen synthesis. In conclusion, the biocomposite reported herein is highly promising for repairing diabetic skin wounds and treating infections caused by bacterial microbes.

The effect of alginate scaffolds on bone healing in defects formed with drilling model in rat femur diaphysis

Alginate (ALG) is a biocompatible and biodegradable polymer. Mechanical weakness is one of the main problems for the alginate-based scaffolds. Various plasticizer additives or modifications tested to improve the mechanical properties. In the presented study, ALG plasticized with triacetin (TA), and tributyl citrate (TBC) than tested on bone healing. In the presented study, the alginate modified with triacetin or tributyl citrate. In-vitro, and in-vivo efficiency of the scaffolds tested on bone tissue regeneration. Scaffolds fabricated by solvent casting, and physicochemical characterizations performed. Monocytes (THP-1) cultured with scaffolds, and macrophage-released cytokines was determined. In-vivo efficacy of the scaffolds was tested in the rat drill hole model. Alginate and tributyl citrate-modified scaffolds have no cytotoxic effect on osteoblastic cells (MC-3T3). Tributyl citrate modification increased tumor necrosis factor-alpha (TNF-alpha) level but did not increase interleukin -1 beta (IL-1 beta) level. In vivo studies showed that osteoblastic growth was significant in alginate and triacetin-modified scaffolds. However, the best values for osteoclastic activity and osteoid tissue formation seen in the triacetin modification. The results demonstrated that the modified alginate scaffolds were more successful than non-modified alginate scaffolds and can used as long-term bone repairing treatments.

Alginates Combined with Natural Polymers as Valuable Drug Delivery Platforms

Alginates (ALG) have been used in biomedical and pharmaceutical technologies for decades. ALG are natural polymers occurring in brown algae and feature multiple advantages, including biocompatibility, low toxicity and mucoadhesiveness. Moreover, ALG demonstrate biological activities per se, including anti-hyperlipidemic, antimicrobial, anti-reflux, immunomodulatory or anti-inflammatory activities. ALG are characterized by gelling ability, one of the most frequently utilized properties in the drug form design. ALG have numerous applications in pharmaceutical technology that include micro- and nanoparticles, tablets, mucoadhesive dosage forms, wound dressings and films. However, there are some shortcomings, which impede the development of modified-release dosage forms or formulations with adequate mechanical strength based on pure ALG. Other natural polymers combined with ALG create great potential as drug carriers, improving limitations of ALG matrices. Therefore, in this paper, ALG blends with pectins, chitosan, gelatin, and carrageenans were critically reviewed.

Alginates for Protection Against Pepsin-Acid Induced Aerodigestive Epithelial Barrier Disruption

OBJECTIVE

Gastroesophageal reflux disease (GERD) and laryngopharyngeal reflux (LPR) are chronic conditions caused by backflow of gastric and duodenal contents into the esophagus and proximal aerodigestive tract, respectively. Mucosal barrier dysfunction resultant from the synergistic actions of chemical injury and the mucosal inflammatory response during reflux contributes to symptom perception. Alginates effectively treat symptoms of mild to moderate GERD and have recently shown benefit for LPR. In addition to forming a "raft" over gastric contents to reduce acidic reflux episodes, alginates have been found to bind the esophageal mucosa thereby preserving functional barrier integrity measured by transepithelial electrical resistance. The aim of this study was to further examine the topical protective capacity of alginate-based Gaviscon Advance (GA) and Double Action (GDA) against pepsin-acid mediated aerodigestive epithelial barrier dysfunction in vitro.

STUDY DESIGN

Translational.

METHODS

Immortalized human esophageal and vocal cord epithelial cells cultured in transwells were pretreated with liquid formula GA, GDA, matched viscous placebo solution, or saline (control), then treated for 1 h with saline, acid (pH 3-6) or pepsin (0.1-1 mg/ml) at pH 3-6. Endpoint measure was taken of horseradish peroxidase (HRP) allowed to diffuse across monolayers for 2 h.

RESULTS

Pepsin (0.1-1 mg/ml) at pH 3-6 increased HRP flux through cultures pretreated with saline or placebo (p < 0.05); acid alone did not. GA and GDA prevented barrier dysfunction.

CONCLUSIONS

GA and GDA preserved epithelial barrier function during pepsin-acid insult better than placebo suggesting that protection was due to alginate. These data support topical protection as a therapeutic approach to GERD and LPR. Laryngoscope, 132:2327-2334, 2022.

Antimicrobial effects of bacterial binding to a dialkylcarbamoyl chloride-coated wound dressing: an in vitro study

OBJECTIVE

Wound dressings that inactivate or sequestrate microorganisms, such as those with a hydrophobic, bacteria-binding dialkylcarbamoyl chloride (DACC) surface, can reduce the risk of clinical infections. This 'passive' bioburden control, avoiding bacterial cell wall disruption with associated release of bacterial endotoxins aggravating inflammation, is advantageous in hard-to-heal wounds. Hence, the full scope of DACC dressings, including the potential impact of higher inoculum densities, increased protein load and different pH on antibacterial activity, needs to be evaluated.

METHOD

The Japanese Industrial Standard (JIS) L 1902 challenge test was used to evaluate the antimicrobial activity of the DACC-coated dressing against several World Health Organization (WHO)-prioritised wound pathogens (e.g., meticillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, microorganisms with extended-spectrum beta-lactamases and Acinetobacter baumannii), the effect of repeated bacterial challenge in an adverse wound environment, and antimicrobial performance at wound-related pH.

RESULTS

High antibacterial activity of the DACC-coated dressing against the WHO-prioritised bacteria strains by its irreversible binding and inhibition of growth of bound bacteria was confirmed using JIS L 1902. At increased inoculation densities, compared to standard conditions, the DACC-coated dressing still achieved strong-to-significant antibacterial effects. Augmenting the media protein content also affected antibacterial performance; a 0.5-1 log reduction in antibacterial activity was observed upon addition of 10% fetal calf serum. The pH did not influence antibacterial performance. The DACC-coated dressing also sustained antibacterial activity over subsequent reinfection steps.

CONCLUSION

It can be assumed that the DACC-coated dressing exerts beneficial effects in controlling the wound bioburden, reducing the overall demand placed on antibiotics, without using antimicrobial substances.

Alginate: Enhancement Strategies for Advanced Applications

Alginate is an excellent biodegradable and renewable material that is already used for a broad range of industrial applications, including advanced fields, such as biomedicine and bioengineering, due to its excellent biodegradable and biocompatible properties. This biopolymer can be produced from brown algae or a microorganism culture. This review presents the principles, chemical structures, gelation properties, chemical interactions, production, sterilization, purification, types, and alginate-based hydrogels developed so far. We present all of the advanced strategies used to remarkably enhance this biopolymer’s physicochemical and biological characteristics in various forms, such as injectable gels, fibers, films, hydrogels, and scaffolds. Thus, we present here all of the material engineering enhancement approaches achieved so far in this biopolymer in terms of mechanical reinforcement, thermal and electrical performance, wettability, water sorption and diffusion, antimicrobial activity, in vivo and in vitro biological behavior, including toxicity, cell adhesion, proliferation, and differentiation, immunological response, biodegradation, porosity, and its use as scaffolds for tissue engineering applications. These improvements to overcome the drawbacks of the alginate biopolymer could exponentially increase the significant number of alginate applications that go from the paper industry to the bioprinting of organs.

Treatment of Chrysanthemum Synthetic Seeds by Air SDBD Plasma

Herein, we present the effect of surface dielectric barrier discharge (SDBD) air cold plasma on regrowth of chrysanthemum synthetic seeds (synseeds) and subsequent plantlet development. The plasma system used in this study operates in air at the frequency of 50 Hz. The detailed electrical characterization of SDBD was shown, as well as air plasma emission spectra obtained by optical emission spectroscopy. The chrysanthemum synseeds (encapsulated shoot tips) were treated in air plasma for different treatment times (0, 5 or 10 min). Plasma treatment significantly improved the regrowth and whole plantlet development of chrysanthemum synseeds under aseptic (in vitro) and non-aseptic (ex vitro) conditions. We evaluated the effect of SDBD plasma on synseed germination of four chrysanthemum cultivars after direct sowing in soil. Germination of synseeds directly sowed in soil was cultivar-dependent and 1.6-3.7 fold higher after plasma treatment in comparison with untreated synseeds. The study showed a highly effective novel strategy for direct conversion of simple monolayer alginate chrysanthemum synseeds into entire plantlets by plasma pre-conversion treatment. This treatment reduced contamination and displayed a considerable ex vitro ability to convert clonally identical chrysanthemum plants.

Smart 3D Printed Hydrogel Skin Wound Bandages: A Review

Wounds are a major health concern affecting the lives of millions of people. Some wounds may pass a threshold diameter to become unrecoverable by themselves. These wounds become chronic and may even lead to mortality. Recently, 3D printing technology, in association with biocompatible hydrogels, has emerged as a promising platform for developing smart wound dressings, overcoming several challenges. 3D printed wound dressings can be loaded with a variety of items, such as antibiotics, antibacterial nanoparticles, and other drugs that can accelerate wound healing rate. 3D printing is computerized, allowing each level of the printed part to be fully controlled in situ to produce the dressings desired. In this review, recent developments in hydrogel-based wound dressings made using 3D printing are covered. The most common biosensors integrated with 3D printed hydrogels for wound dressing applications are comprehensively discussed. Fundamental challenges for 3D printing and future prospects are highlighted. Additionally, some related nanomaterial-based hydrogels are recommended for future consideration.

Assessment of the Antigenotoxic Effects of Alginate and ZnO/Alginate-Nanocomposites Extracted from Brown Alga Fucus vesiculosus in Mice

Mitomycin C (MMC) is an alkylating chemotherapy drug that could induce DNA damage and genetic alteration. It has been used as a model mutagen for in vivo and in vitro studies. The current study aimed to evaluate the protective role of Zinc oxide alginate–nanocomposites (ZnO-Alg/NCMs) against MMC–induced genotoxicity in mice. Animals were treated as follows: the control group, the groups treated with Algin (400 mg/kg b.w), the groups treated with ZnO-Alg/NCMs (400 mg/kg b.w), the group treated with MMC, and the groups treated with MMC plus Algin or ZnO-Alg/NCMs. Pre-treatment with Algin and ZnO-Alg/NCMs was repeated for one or seven days. Zinc oxide alginate-nanocomposites (ZnO-Alg/NCMs) were synthesized with the aim of incorporating the intrinsic properties of their constituents as an antigenotoxic substance. In this study, alginate was extracted from the brown marine alga Fucus vesiculosus, Zinc oxide nanoparticles were synthesized by using water extract of the same alga, and loaded in alginate to synthesize ZnO-Alg/NCMs. ZnO-NPs and ZnO-Alg/NCMs were characterized by TEM, SEM, EDX, and Zeta potential. The obtained results confirmed that by TEM and SEM, ZnO-NPs are rod shaped which modified, when loaded in alginate matrix, into spherical shape. The physical stability of ZnO-Alg/NCMs was reported to be higher than ZnO-NPs due to the presence of more negative charges on ZnO-Alg/NCMs. The EDX analysis indicated that the amount of zinc was higher in ZnO-NPs than ZnO-Alg/NCMs. The in vivo results showed that treatment with MMC induced genotoxic disturbances. The combined treatment with Algin and ZnO-Alg/NCMs succeeded in inducing significant protection against MMC. It could be concluded that ZnO-Algin/NCMs is a promising candidate to protect against MMC–induced genotoxicity.

Nature-Based Biomaterials and Their Application in Biomedicine

Natural polymers, based on proteins or polysaccharides, have attracted increasing interest in recent years due to their broad potential uses in biomedicine. The chemical stability, structural versatility, biocompatibility and high availability of these materials lend them to diverse applications in areas such as tissue engineering, drug delivery and wound healing. Biomaterials purified from animal or plant sources have also been engineered to improve their structural properties or promote interactions with surrounding cells and tissues for improved in vivo performance, leading to novel applications as implantable devices, in controlled drug release and as surface coatings. This review describes biomaterials derived from and inspired by natural proteins and polysaccharides and highlights their promise across diverse biomedical fields. We outline current therapeutic applications of these nature-based materials and consider expected future developments in identifying and utilising innovative biomaterials in new biomedical applications.

Current Trends in Advanced Alginate-Based Wound Dressings for Chronic Wounds

Chronic wounds represent a major public health issue, with an extremely high cost worldwide. In healthy individuals, the wound healing process takes place in different stages: inflammation, cell proliferation (fibroblasts and keratinocytes of the dermis), and finally remodeling of the extracellular matrix (equilibrium between metalloproteinases and their inhibitors). In chronic wounds, the chronic inflammation favors exudate persistence and bacterial film has a special importance in the dynamics of chronic inflammation in wounds that do not heal. Recent advances in biopolymer-based materials for wound healing highlight the performance of specific alginate forms. An ideal wound dressing should be adherent to the wound surface and not to the wound bed, it should also be non-antigenic, biocompatible, semi-permeable, biodegradable, elastic but resistant, and cost-effective. It has to give protection against bacterial, infectious, mechanical, and thermal agents, to modulate the level of wound moisture, and to entrap and deliver drugs or other molecules This paper explores the roles of alginates in advanced wound-dressing forms with a particular emphasis on hydrogels, nanofibers networks, 3D-scaffolds or sponges entrapping fibroblasts, keratinocytes, or drugs to be released on the wound-bed. The latest research reports are presented and supported with in vitro and in vivo studies from the current literature.

A Novel Orthotopic Liver Cancer Model for Creating a Human-like Tumor Microenvironment

Simple Summary

Hepatocellular carcinoma is the most common form of liver cancer. The lack of models that resemble actual tumor development in patients, limits the research to improve the diagnosis rate and develop new treatments. This study describes a novel mouse model that involves organoid formation and an implantation technique. This mouse model shares human genetic profiles and factors around the tumor, resembling the actual tumor development in patients. We demonstrate the roles of different cell types around the tumor, in promoting tumor growth, using this model. This model will be useful to understand the tumor developmental process, drug testing, diagnosis, prognosis, and treatment development.

Abstract

Hepatocellular carcinoma (HCC) is the most common form of liver cancer. This study aims to develop a new method to generate an HCC mouse model with a human tumor, and imitates the tumor microenvironment (TME) of clinical patients. Here, we have generated functional, three-dimensional sheet-like human HCC organoids in vitro, using luciferase-expressing Huh7 cells, human iPSC-derived endothelial cells (iPSC-EC), and human iPSC-derived mesenchymal cells (iPSC-MC). The HCC organoid, capped by ultra-purified alginate gel, was implanted into the disrupted liver using an ultrasonic homogenizer in the immune-deficient mouse, which improved the survival and engraftment rate. We successfully introduced different types of controllable TME into the model and studied the roles of TME in HCC tumor growth. The results showed the role of the iPSC-EC and iPSC-MC combination, especially the iPSC-MC, in promoting HCC growth. We also demonstrated that liver fibrosis could promote HCC tumor growth. However, it is not affected by non-alcoholic fatty liver disease. Furthermore, the implantation of HCC organoids to humanized mice demonstrated that the immune response is important in slowing down tumor growth at an early stage. In conclusion, we have created an HCC model that is useful for studying HCC development and developing new treatment options in the future.

Alginate/poloxamer hydrogel obtained by thiol-acrylate photopolymerization for the alleviation of the inflammatory response of human keratinocytes

Hydrogel-based wound dressings have been intensively studied as promising materials for wound healing and care. The mixed-mode thiol-acrylate photopolymerization is used in this paper for alginate/poloxamer hydrogels formation. First, the alginate was modified with thiol groups using the esterification reaction with cysteamine, and second, the terminal hydroxyl groups of poloxamer were esterified with acryloyl chloride to introduce polymerizable acrylate groups. Finally, the cross-linking reaction between the two macromers was performed to produce degradable alginate/poloxamer hydrogels. The optimum conditions for the photo-initiated reaction were studied in order to obtain high gel fractions. The resulting hydrogels have high swelling capacity in simulated physiological conditions, good elasticity and strength, and appropriate porosity, some of the physico-chemical properties required for their applications as wound dressings/patches. The biological assays show that the alginate/poloxamer hydrogels induce proliferation of human keratinocyte and have an anti-inflammatory effect on lipopolysaccharides (LPS)-activated keratinocytes by inhibiting the extracellular signal-regulated kinases (ERK)/ nuclear factor (NF)-kB/ tumor necrosis factor (TNF)-α signalling pathway. Taken together, the results showed that the chemical cross-linked alginate/poloxamer hydrogels may function as a dressing/patch applied directly on the skin lesion to heal the wound by reducing the exacerbated inflammation, the main cause of wound healing delay and local infection.

Electrospun Scaffolds in Periodontal Wound Healing

Periodontitis is a set of inflammatory conditions affecting the tissues surrounding the teeth predominantly sustained by bacterial infections. The aim of the work was the design and the development of scaffolds based on biopolymers to be inserted in the periodontal pocket to restore tissue integrity and to treat bacterial infections. Nanofibrous scaffolds were prepared by means of electrospinning. Gelatin was considered as base component and was associated to low and high molecular weight chitosans and alginate. The scaffolds were characterized by chemico–physical properties (morphology, solid state-FTIR and differential scanning calorimetry (DSC)-surface zeta potential and contact angle), and mechanical properties. Moreover, preclinical properties (cytocompatibility, fibroblast and osteoblast adhesion and proliferation and antimicrobial properties) were assessed. All the scaffolds were based on cylindrical and smooth nanofibers and preserved their nanofibrous structure upon hydration independently of their composition. They possessed a high degree of hydrophilicity and negative zeta potentials in a physiological environment, suitable surface properties to enhance cell adhesion and proliferation and to inhibit bacteria attachment. The scaffold based on gelatin and low molecular weight chitosan proved to be effective in vitro to support both fibroblasts and osteoblasts adhesion and proliferation and to impair the proliferation of Streptococcus mutans and Aggregatibacter actinomycetemcomitans, both pathogens involved in periodontitis.

Green preparation of anti-inflammation an injectable 3D porous hydrogel for speeding up deep second-degree scald wound healing

Scalds are one of the most common injuries and the 4th cause of trauma globally. Alginate has emerged as a promising scald wound dressing. Herein, we present a facile applicable strategy for electron beam (EB) radiation crosslinking gelatin, alginate, and carboxymethyl cellulose (CMC) into an injectable three-dimensional (3D) porous hydrogel (3D-PH) with a double crosslinked network for reliable deep second-degree scald wound healing. In addition, the injectable 3D-PH stimulated proliferation and migration of dermal fibroblasts in vitro and the deep second-degree scald wound healing process is accelerated in vivo. Most importantly, in vitro results revealed that the injectable 3D-PH stimulated cell proliferation via inducing the expression of Ki-67, and suppressed inflammatory signals as indicated by the downregulation of inflammatory factors (IL-6, TNF-α) in L929 cells. We further demonstrated that the 3D-PGH accelerated the wound healing process of deep second-degree scald in vivo. This study indicated the injectable 3D-PH with a double crosslinked network could be applied as a multifunctional injectable scald wound dressing material for anti-inflammation, necrotic tissue-removal, and wound closure. These findings suggest that the injectable 3D-PH may be conducive to the evolution of new pharmaceuticals for burn wound healing.

Novel alginate-chitosan aerogel fibres for potential wound healing applications

Aerogels produced from marine polymers, such as chitosan and alginate, are of interest for wound healing applications due to their attractive properties. These properties can be the aerogel's high porosity along with the antimicrobial activity of chitosan or the capacity to provide a moist environment of alginate. The aim of this work was to develop a new route towards hybrid alginate-chitosan aerogel fibres and to evaluate their potential for wound healing applications. The influence of chitosan molecular weight and its content on the fibres characteristics was evaluated. To produce the fibres, the formation of polyelectrolyte complex hydrogels of both polymers was performed by the emulsion-gelation method. Hydrogels were converted in alcogels through a solvent exchange followed by drying with supercritical CO₂. Resulting aerogels were observed to be light-weight, fluffy mesoporous fibres with a specific surface area of 162-302 m²/g and specific pore volume of 1.41-2.49 cm³/g. Biocompatibility of the fibres was evaluated, and the result showed that they were non-cytotoxic. Bioactivity of the fibres regarding the ability to close a wound on an in vitro scale and antibacterial activity were also evaluated. Aerogel fibres presented percentages of recovered scratch area of about 75%, higher than the untreated control (~50%) and a clear antibacterial activity against Staphylococcus aureus and Klebsiella pneumoniae. The obtained results suggest that these alginate-chitosan aerogel fibres could be good candidates for wound healing applications.

Tryptanthrin promotes keratinocyte and fibroblast responses in vitro after infection with Trichophyton benhamiae DSM6916

Exceedingly virulent pathogens and growing antimicrobial resistances require new therapeutic approaches. The zoophilic dermatophyte Trichophyton benhamiae causes highly inflammatory, cutaneous fungal infections. Recently, it could be shown that the plant-derived alkaloid tryptanthrin (TRP) exhibits strong anti-microbial activities against yeasts and dermatophytes. The aim of this study was to analyse the bioactivity of TRP under infectious conditions using an in-vitro dermatophytosis model employing fibroblasts and keratinocytes infected with T. benhamiae DSM6916. Analyses comprised determination of cell viability, effects on the innate immune response including expression and secretion of pro-inflammatory cytokines/chemokines as well as expression of various antimicrobial peptides (AMP), toll-like receptor (TLR) 2 and proliferation marker MKI67. T. benhamiae caused severe inflammation in the cutaneous cell models. TRP almost fully prevented T. benhamiae-derived damage of dermal fibroblasts and substantially reduced it in epidermal keratinocytes. A distinct down-regulation of the expression and secretion of pro-inflammatory cytokines was observed. Further, TRP promoted AMP expression, especially of HBD2 and HBD3, in keratinocytes even without fungal presence. This study provides crucial evidence that TRP is not only a strong antifungal agent but also potentially modulates the innate immune response. This makes it interesting as a natural antimycotic drug for adjuvant treatment and prevention of fungal re-infection.

Assessment of the Efficacy of Tributylammonium Alginate Surface-Modified Polyurethane as an Antibacterial Elastomeric Wound Dressing for both Noninfected and Infected Full-Thickness Wounds

Risk factors of nonhealing wounds include persistent bacterial infections and rapid onset of dehydration; therefore, wound dressings should be used to accelerate the healing process by helping to disinfect the wound bed and provide moisture. Herein, we introduce a transparent tributylammonium alginate surface-modified cationic polyurethane (CPU) wound dressing, which is appropriate for full-thickness wounds. We studied the physicochemical properties of the dressing using Fourier transform infrared, ¹H NMR, and ¹³C NMR spectroscopies and scanning electron microscopy, energy-dispersive X-ray, and thermomechanical analyses. The surface-modified polyurethane demonstrated improved hydrophilicity and tensile Young's modulus that approximated natural skin, which was in the range of 1.5-3 MPa. Cell viability and in vitro wound closure, assessed by MTS and the scratch assay, confirmed that the dressing was cytocompatible and possessed fibroblast migratory-promoting activity. The surface-modified CPU had up to 100% antibacterial activity against Staphylococcus aureus and Escherichia coli as Gram-positive and Gram-negative bacteria, respectively. In vivo assessments of both noninfected and infected wounds revealed that the surface-modified CPU dressing resulted in a faster healing rate because it reduced the persistent inflammatory phase, enhanced collagen deposition, and improved the formation of mature blood vessels when compared with CPU and commercial Tegaderm wound dressing.

Wound healing properties of magnesium mineralized antimicrobial nanofibre dressings containing chondroitin sulphate – a comparison between blend and core–shell nanofibres

Effect of chondroitin sulphate incorporated PCL/gelatin as blends or core–shell composite nanofibres are compared in terms of their biocompatibility for skin cells and wound healing in porcine model of partial thickness burns.

Chitosan-calcium alginate dressing promotes wound healing: A preliminary study

Dressings are necessary during the process of wound healing. Since the early 1980s, several types of wound dressings have been produced, but they cannot always take into account some effects include antibacterial effect, wound healing promotion, and other properties. In this study, we would like to develop an effective dressing with the above properties, especially accelerating wound healing effect. A chitosan-calcium alginate dressing (CCAD) was developed by coating mixture of chitosan with high-low molecular weight on calcium alginate dressing (CAD). We investigated the structural characteristics of CCAD with Fourier-transform infrared spectroscopy (FTIR) and electron microscopy. The cytotoxicity and antibacterial property were evaluated in vitro using CCK-8 and inhibition zone method. Moisture retention was tested on the skin of Sprague-Dawley (SD) rats, and wound healing studies were performed on a full-thickness skin wound model in SD rats. CCAD showed good moisturizing and antibacterial properties with no cytotoxicity. CCAD could inhibit inflammation by decreasing IL-6, and it could also promote angiogenesis by increasing VEGF, resulting in better wound healing than CAD. CCAD is a better choice in wound care due to its antibacterial property, biocompatibility, moisture retention, healing promotion, and non-cytotoxicity characteristics.

Oral Bone Tissue Engineering: Advanced Biomaterials for Cell Adhesion, Proliferation and Differentiation

The advancements made in biomaterials have an important impact on oral tissue engineering, especially on the bone regeneration process. Currently known as the gold standard in bone regeneration, grafting procedures can sometimes be successfully replaced by a biomaterial scaffold with proper characteristics. Whether natural or synthetic polymers, biomaterials can serve as potential scaffolds with major influences on cell adhesion, proliferation and differentiation. Continuous research has enabled the development of scaffolds that can be specifically designed to replace the targeted tissue through changes in their surface characteristics and the addition of growth factors and biomolecules. The progress in tissue engineering is incontestable and research shows promising contributions to the further development of this field. The present review aims to outline the progress in oral tissue engineering, the advantages of biomaterial scaffolds, their direct implication in the osteogenic process and future research directions.

Cold atmospheric pressure plasmas exhibit antimicrobial properties against critical bacteria and yeast species

OBJECTIVE

Cold atmospheric pressure plasmas (CAPPs) have been used to sterilise implant materials and other thermally unstable medical products and to modify chemical surfaces. This study investigates the antimicrobial effect of the gas and input power used to generate CAPPs on microorganisms causing skin infections, such as Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Malassezia pachydermatis.

METHOD

Microorganisms were cultivated on Mueller Hinton 2 (MH2) agar plates. CAPP treatment was performed using the Plasma BLASTER MEF. To investigate the antimicrobial effects the following CAPP parameters were varied: the gas used, input power, as well as number of treatments and treatment time.

RESULTS

The antimicrobial efficacy of the CAPPs was found to increase with increasing input power and treatment time (or cycles). Furthermore the plasma generated from nitrogen is more effective than from air.

CONCLUSION

The study showed that CAPPs demonstrate strong bactericidal and fungicidal properties in vitro. The selective application of CAPPs for the treatment of wound infections may offer a promising supplementary tool alongside current therapies.

Injectable Scaffolds Enriched with Silver to Inhibit Bacterial Invasion in Tissue Regeneration

During wound healing, bacterial infections may prolong skin regeneration and tissue repair, causing delayed or incomplete healing. The therapeutic strategies currently used include general therapeutic modes, growth factors, skin substitutes, matrices and/or cell therapy. Among recent technologies, wound dressing materials comprising silver nitrate or silver sulfadiazine as the antimicrobial agent are widespread, despite their known cytotoxicity. The aim of this work was to develop and evaluate the efficacy of gelatinous injectable biomaterials composed of collagen and alginates, enriched with silver against bacterial pathogens commonly involved in wound infections. To reduce cytotoxicity, silver was used as lactate and saccharinated salts. Results show that silver-enriched beads were effective against both Gram-positive and Gram-negative strains in a concentration-dependent manner. Silver addition was more active against Staphylococcusepidermidis than against Pseudomonasaeruginosa. The antibacterial activity was localized only in the area of contact with the beads at concentrations lower than 0.3 mM, whereas at higher concentrations a larger inhibition halo was observed. No cytotoxic effect on eukaryotic cells was seen both testing the materials’ extracts or the Ag-doped beads in contact tests. These results, although preliminary, suggest that these scaffolds are a promising approach for realizing injectable or spreadable functional biomaterials with antibacterial activity for applications in wound management.

A straightforward method for quantification of vinyl functionalized water soluble alginates via 13C-NMR spectroscopy

Alginates are fairly abundant in nature and possess many interesting properties, including their biocompatibility and ability to absorb large amounts of water. Hence, increasing interest in their derivatization has been observed and the determination of the number of newly introduced functionalities has become a key issue. For this purpose, literature generally reports on conventional ¹H-NMR spectra, typically recorded at elevated temperatures and/or after hydrolysis of the alginate to circumvent line broadening effects resulting from the high viscosity. The present work reports on the modification of alginate with methacrylate functionalities and determination of the resulting degree of substitution (DS), i.e. the number of introduced methacrylate moieties relative to the initial amount of hydroxyl groups along the alginate backbone, via NMR spectroscopy. Freeze-drying and low power water presaturation were applied to improve the quality of the ¹H NMR spectra. Nevertheless, it remains a qualitative method, to be used only for mutual comparisons of samples. A new and accurate method for DS determination of methacrylated alginates, based on ¹³C-NMR spectroscopy, is proposed. Quantitative ¹³C-NMR spectra were recorded with reduced measuring times by addition of a paramagnetic relaxation agent. The proposed method will also be applicable for other water-soluble functionalized alginates and polysaccharides in general.

Use of Silver-Containing Hydrofiber and Chlorhexidine-Impregnated Tulle Gras Dressings for Second-Degree Burns

OBJECTIVE

This study evaluated the use of silver-containing hydrofiber and chlorhexidine-impregnated tulle gras dressings for second-degree burns.

METHODS

This randomized clinical study consisted of 60 patients with second-degree burns. Data were collected using a Patient Identification Form, Wound Assessment Form, and Pain Assessment Scale. Following dressing application, wounds were assessed on days 7, 15, and 22. Study procedures were continued until full epithelialization occurred.

RESULTS

After the seventh day of follow-up, significant improvement was noted in the experimental group in terms of wound exudate, wound debridement, pain intensity, and analgesic agent administration. After the 15th day of follow-up, there was a significant decrease in epithelialization time in the experimental group. Exudate control was better in patients whose burns were treated with silver-containing hydrofiber dressings, and they needed less debridement and fewer analgesics because of infrequent dressing changes. Lower pain scores were reported, the burn area reduced more quickly, and faster epithelialization and wound healing were achieved.

CONCLUSIONS

The authors conclude that silver-containing hydrofiber dressings are an effective wound care material that improve the wound healing process. More studies comparing it and other wound care materials could improve the quality of healthcare for patients with burns.

Size-Dependent Effect of Silver Nanoparticles on the Tumor Necrosis Factor α-Induced DNA Damage Response

Silver nanoparticles (AgNPs) are widely used in many consumer products due to their anti-inflammatory properties. Therefore, the effect of exposure to AgNPs should be investigated in diseased states in addition to healthy ones. Tumor necrosis factor-α (TNFα) is a major cytokine that is highly expressed in many diseased conditions, such as inflammatory diseases, sepsis, and cancer. We investigated the effects of two different sizes of AgNPs on the TNFα-induced DNA damage response. Cells were exposed to 10 and 200 nm AgNPs separately and the results showed that the 200 nm AgNPs had a lower cytotoxic effect with a higher percent of cellular uptake compared to the 10 nm AgNPs. Moreover, analysis of reactive oxygen species (ROS) generation and DNA damage indicated that TNFα-induced ROS-mediated DNA damage was reduced by 200 nm AgNPs, but not by 10 nm AgNPs. Tumor necrosis factor receptor 1 (TNFR1) was localized on the cell surface after TNFα exposure with or without 10 nm AgNPs. In contrast, the expression of TNFR1 on the cell surface was reduced by the 200 nm AgNPs. These results suggested that exposure of cells to 200 nm AgNPs reduces the TNFα-induced DNA damage response via reducing the surface expression of TNFR1, thus reducing the signal transduction of TNFα.

Mechanical Augmentation With Absorbable Alginate Sheet Enhances Healing of the Rotator Cuff

For anatomical restoration of a repaired rotator cuff, mechanical augmentation of the repaired structure is essential. Using histological and biomechanical evaluation in a rat model, the authors sought to determine the efficacy of an absorbable alginate sheet at the supraspinatus tendon-to-bone repair site for healing of the rotator cuff tear. Forty adult (12 weeks old) male Sprague- Dawley wild-type rats were used in this study. The animals were randomly separated into 2 groups: group 1, conventional supraspinatus repair with acute repair; or group 2, supraspinatus repair with absorbable alginate sheet. Biomechanical and histological analyses were performed at 6 and 12 weeks after index rotator cuff surgery. Compared with group 1, group 2 exhibited a significantly greater mean ultimate failure load (group 1, 23.70±3.87 N; group 2, 61.44±43.67 N; P=.023) and mean ultimate stress (group 1, 2.83±0.50 MPa; group 2, 7.36±2.87 MPa; P=.020). However, 6-week outcomes were not significantly different. On histological scoring, compared with group 1, group 2 exhibited a significantly greater mean 6-week score (group 1, 4.10±1.72 points; group 2, 7.80±1.47 points; P<.001) and mean 12-week score (group 1, 3.50±1.00 points; group 2, 5.25±2.62 points; P=.020). Mechanical augmentation with absorbable alginate may improve tendon healing after surgical repair of the rotator cuff. [Orthopedics. 2019; 42(1):e104-e110.].

Macroalgal Polysaccharides in Biomimetic Nanodelivery Systems

BACKGROUND

Imitating nature in the design of bio-inspired drug delivery systems resulted in several success stories. However, the practical application of biomimicry is still largely unrealized owing to the fact that we tend to copy the shape more often than the whole biology. Interesting chemistry of polysaccharides provides endless possibilities for drug complex formation and creation of delivery systems with diverse morphological and surface properties. However, the type of biological response, which may be induced by these systems, remains largely unexploited.

METHODS

Considering the most current research for the given topic, in this review, we will try to present the integrative approaches for the design of biomimetic DDS's with improved therapeutic or theranostic effects based on different algal polysaccharides that exert multiple biological functions.

RESULTS

Algal polysaccharides may provide building blocks for bioinspired drug delivery systems capable of supporting the mechanical properties of nanomedicines and mimicking various biological processes by molecular interactions at the nanoscale. Numerous research studies demonstrate the efficacy and safety of multifunctional nanoparticles integrating several functions in one delivery system, composed of alginate, carrageenan, ulvan, fucoidan and their derivatives, intended to be used as bioartificial microenvironment or for diagnosis and therapy of different diseases.

CONCLUSION

Nanodimensional structure of polysaccharide DDS's shows substantial influence on the bioactive motifs potential availability for interaction with a variety of biomolecules and cells. Evaluation of the nano dimensional structure-activity relationship is crucial for unlocking the full potential of the future application of polysaccharide bio-mimicking DDS in modern diagnostic and therapeutic procedures.