Investigation of anti-adhesion ability of 8-arm PEGNHS-modified porcine pericardium

In post-adhesion surgery, there is a clinical need for anti-adhesion membranes specifically designed for the liver, given the limited efficacy of current commercial products. To address this demand, we present a membrane suitable for liver surgery applications, fabricated through the modification of decellularized porcine pericardium with 20 KDa hexaglycerol octa (succinimidyloxyglutaryl) polyoxyethylene (8-arm PEGNHS). We also developed an optimized modification procedure to produce a high-performance anti-adhesion barrier. The modified membrane significantly inhibited fibroblast cell adherence while maintaining minimal levels of inflammation. By optimizing the modification ratio, we successfully controlled post-adhesion formation. Notably, the 8-arm PEG-modified pericardium with a molar ratio of 5 exhibited the ability to effectively prevent post-adhesion formation on the liver compared to both the control and Seprafilm®, with a low adhesion score of 0.5 out of 3.0. Histological analysis further confirmed its potential for easy separation. Furthermore, the membrane demonstrated regenerative capabilities, as evidenced by the proliferation of mesothelial cells on its surface, endowing anti-adhesion properties between the abdominal wall and liver. These findings highlight the membrane's potential as a reliable barrier for repeated liver resection procedures that require the removal of the membrane multiple times.

Barbed sutures and skin adhesives improve wound closure in hip and knee arthroplasty

PURPOSE

This study aimed to formulate evidence-based recommendations for optimising wound management in hip and knee arthroplasty by exploring alternative methods such as barbed sutures and skin adhesives.

METHODS

A Delphi panel, comprising seven orthopaedic surgeons, one musculoskeletal infectious disease specialist, and one health economics expert, was convened to evaluate the use of barbed sutures and skin adhesives for wound closure in hip and knee arthroplasty. Two systematic reviews informed the development of questionnaires, with panelists ranking their agreement on statements using a 5-point Likert scale. Consensus was achieved if ≥75% agreement. Unresolved statements were revisited in a second round.

RESULTS

Consensus was reached on 11 statements, providing evidence-based recommendations. The expert panel advocates for a multilayer watertight technique using barbed sutures to prevent surgical site infections (SSI), reduce complications, shorten surgical times, optimise resources and improve cosmetic appearance. For skin closure, the panel recommends topical adhesives to decrease wound dehiscence, enhance cosmetic appearance, promote patient compliance, prevent SSIs, and optimise resources.

CONCLUSION

The Delphi consensus by Italian total joint arthroplasty experts underscores the pivotal role of barbed sutures and skin adhesives in optimising outcomes. While guiding clinical decision-making, these recommendations are not prescriptive and should be adapted to local practices. The study encourages further research to enhance current evidence.

LEVEL OF EVIDENCE

Level III.

[Research Progress and Design Strategy of Hemostatic Adhesives]

Adhesives have emerged as an effective method for wound closure, hemostasis and tissue engineering in recent years, which not only are suitable for the adhesion of wet tissues, but also can adapt to the peristalsis and mechanical stretching of tissues and organs, especially for arteries and organize bleeding. With the further development of technology, existing adhesives can be modified through different strategies, and new materials are explored, giving new properties and uses to adhesives, such as drug delivery, temperature sensitivity, light sensitivity and so on. Nevertheless, there are many questions about the design and practical clinical application of adhesives in the future. The recent research progress of traditional adhesives and their application in hemostasis is reviewed, and the design and development ideas of future adhesives are discussed in the study.

Suturing Versus Adhesion for Mesh Fixation in Ventral Hernia Repair and Abdominal Wall Reconstruction: A Systematic Review and Network Meta-Analysis

Abdominal wall reconstruction (AWR) is a surgical procedure performed to address various conditions such as hernias, incisional hernias, and complex abdominal wall defects. Mesh fixation plays a crucial role in providing mechanical reinforcement to the weakened abdominal wall during AWR. Traditionally, suturing has been the preferred method for mesh fixation; however, adhesion techniques using tissue adhesives or glues have gained attention as an alternative approach. This systematic review aims to compare suturing and adhesion techniques for mesh fixation in AWR and assess their effectiveness in preventing hernia recurrence. A comprehensive literature search was conducted across relevant databases, including PubMed, MEDLINE, Embase, and the Cochrane Library. Studies that fulfilled the predetermined eligibility criteria were included. The primary outcome measure of interest was hernia recurrence rates. Secondary outcomes included mesh-related complications, surgical site infections, patient-reported outcomes, and functional outcomes. A risk of bias assessment was performed for the included studies, and data were synthesized qualitatively. Overall, the results of the included studies suggest that atraumatic mesh fixation with glue may have the potential to reduce chronic groin pain (CGP). However, there were significant variations in patient selection criteria, glue administration techniques, and hernia repair methods among the trials, which limited the ability to draw definitive conclusions. Additionally, the definitions of CGP and measurement scales for postoperative pain varied across studies, making it challenging to compare outcomes. The limitations of the review include the small sample sizes in some trials, relatively short follow-up durations, and the lack of standardized criteria for assessing variables such as foreign body sensation and groin compliance. Furthermore, the economic implications of using glue fixation compared to traditional suture fixation need to be considered.

Bioactive citrate-based polyurethane tissue adhesive for fast sealing and promoted wound healing

As a superior alternative to sutures, tissue adhesives have been developed significantly in recent years. However, existing tissue adhesives struggle to form fast and stable adhesion between tissue interfaces, bond weakly in wet environments and lack bioactivity. In this study, a degradable and bioactive citrate-based polyurethane adhesive is constructed to achieve rapid and strong tissue adhesion. The hydrophobic layer was created with polycaprolactone to overcome the bonding failure between tissue and adhesion layer in wet environments, which can effectively improve the wet bonding strength. This citrate-based polyurethane adhesive provides rapid, non-invasive, liquid-tight and seamless closure of skin incisions, overcoming the limitations of sutures and commercial tissue adhesives. In addition, it exhibits biocompatibility, biodegradability and hemostatic properties. The degradation product citrate could promote the process of angiogenesis and accelerate wound healing. This study provides a novel approach to the development of a fast-adhering wet tissue adhesive and provides a valuable contribution to the development of polyurethane-based tissue adhesives.

Tissue-Adhesive Hydrogel Spray System for Live Cell Immobilization on Biological Surfaces

Gelatin hydrogels are used as three-dimensional cell scaffolds and can be prepared using various methods. One widely accepted approach involves crosslinking gelatin amino groups with poly(ethylene glycol) (PEG) modified with N-hydroxysuccinimide ester (PEG-NHS). This method enables the encapsulation of live cells within the hydrogels and also facilitates the adhesion of the hydrogel to biological tissues by crosslinking their surface amino groups. Consequently, these hydrogels are valuable tools for immobilizing cells that secrete beneficial substances in vivo. However, the application of gelatin hydrogels is limited due to the requirement for several minutes to solidify under conditions of neutral pH and polymer concentrations suitable for live cells. This limitation makes it impractical for use with biological tissues, which have complex shapes or inclined surfaces, restricting its application to semi-closed spaces. In this study, we propose a tissue-adhesive hydrogel that can be sprayed and immobilized with live cells on biological tissue surfaces. This hydrogel system combines two components: (1) gelatin/PEG-NHS hydrogels and (2) instantaneously solidifying PEG hydrogels. The sprayed hydrogel solidified within 5 s after dispensing while maintaining the adhesive properties of the PEG-NHS component. The resulting hydrogels exhibited protein permeability, and the viability of encapsulated human mesenchymal stem/stromal cells (hMSCs) remained above 90% for at least 7 days. This developed hydrogel system represents a promising approach for immobilizing live cells on tissue surfaces with complex shapes.

Comparing the effect of tissue adhesive and suturing material on collagen I/III ratio in abdominal skin wounds: an experimental study

Background

The skin closure procedure should be technically simple, acceptable, quick, and cost-effective. Sutures remain the technique's mainstay, however tissue adhesive is becoming more used in clinical practice. Collagen ratios of types I and III play a significant role as postoperative wound healing parameters. Here, the authors aim to examine the collagen I/III ratio of tissue adhesive vs. non-absorbable sutures for abdominal skin closure in Wistar albino rats.

Material and methods

The authors allocated 20 rats into four experimental groups. Wounds in groups 1 and 3 were sealed with tissue adhesive (cyanoacrylate), while those in groups 2 and 4 were closed using suture material (monofilament non-absorbable nylon). Groups 1 and 2 were sacrificed on postoperative day (POD) 4, while those in groups 3 and 4 were euthanized on POD 7. Skin samples (1×0.5 cm) were collected for analysis, and the collagen I/III ratios were determined using immunohistochemistry staining techniques.

Results

The levels of collagen I and III expression did not exhibit statistically significant differences between tissue adhesive and nylon suture groups at either POD 4 (P=0.052, P=0.513) or POD 7 (P=0.125, P=0.80). Similarly, the collagen I/III ratio did not significantly differ between the two groups at POD 4 (1.23±2.26 vs. 0.70±0.24; P=0.47) or POD 7 (0.68±0.96 vs. 0.77±1.22; P=0.857).

Conclusions

There were no statistical significance difference in collagen I/III ratio between the tissue adhesive and suture material groups, suggesting that the choice of wound closure material may not influence the abdominal skin closure.

The outcome of sutured wounds compared with tissue adhesive for paediatric wound closure: A meta-analysis

A meta-analysis investigation was executed to measure the outcome of sutured wounds (SWs) compared with tissue adhesive (TA) for paediatric wound closure (PWC). A comprehensive literature inspection till February 2023 was applied and 2018 interrelated investigations were reviewed. The 18 chosen investigations enclosed 1697 children with PWC in the chosen investigations' starting point, 977 of them were utilising SWs, and 906 were utilising TA. Odds ratio (OR) in addition to 95% confidence intervals (CIs) were used to compute the value of the effect of SWs compared with TA for PWC by the dichotomous approaches and a fixed or random model. SWs had significantly higher wound cosmetic (WC) scores (mean deviation [MD], 1.70; 95% CI, 0.57-2.84, P = .003), lower wound dehiscence (WD) (OR 0.60; 95% CI, 0.06-0.43, P < .001), and lower cost (MD, -10.22; 95% CI, -10.94 to -9.50, P < .001) compared with those with TA in PWC. No significant difference was found between children utilising SWs and TA in wound infection (WI) (OR, 0.45; 95% CI, 0.15-1.30, P = .14) with no heterogeneity (I2  = 0%) in PWC. SWs had significantly higher WC scores, lower WD, and lower cost, yet, no significant difference was found in WI compared with those with TA in PWC. However, care must be exercised when dealing with its values because of the low sample size of some of the nominated investigations and the low number of selected investigations for the meta-analysis.

Less-Suture Vascular Anastomosis: Development of Alternative Protocols with Multifunctional Self-Wrapping, Transparent, Adhesive, and Elastic Biomaterials

Blood vessel anastomosis by suture is a life-saving, yet time-consuming and labor-intensive operation. While suture-less alternatives utilizing clips or related devices are developed to address these shortcomings, suture anastomosis is still overwhelmingly used in most cases. In this study, practical "less-suture" strategies are proposed, rather than ideal "suture-less" methods, to reflect real-world clinical situations. In the case of rat artery (d = 0.64 mm) anastomosis, the less-suture anastomosis involves the application of thin, adhesive, transparent, and self-wrapping films to the site. This surprisingly reduces the number of stitches required from ten (without films) to four (with films), saving 27 min of operating time per vessel. Furthermore, the decreased number of stitches largely alleviates fibrosis-mediated wall-thickening. Thus, a less-suture strategy is particularly useful for anastomosis of multiple vessels in emergency conditions and small-diameter vessels.

Locally Administered Photodynamic Therapy for Cancer Using Nano-Adhesive Photosensitizer

Photodynamic therapy (PDT) is a great potential anti-tumor therapy owing to its non-invasiveness and high spatiotemporal selectivity. However, systemically administered photosensitizers diffuse in the skin and the eyes for a long duration, which cause phototoxicity to bright light and sunlight. Therefore, following PDT, patients must avoid exposure of to light and sunlight to avoid this phototoxicity. In this study, we have developed a locally administered PDT using nano-adhesive porphyrin with polycations consisting of quaternary ammonium salt groups (aHP) as a photosensitizer. The aHP, approximately 3.0 nm in diameter, adhered the negatively charged cell membrane via electrostatic interaction. The aHP localized to the endosome via cell adhesion and induced apoptosis upon 635 nm light irradiation. On being administered subcutaneously on the tumor, 30% of the injected aHP remained in the administered sites. However, low-molecular-weight hematoporphyrin dihydrochloride (HP) disappeared due to rapid diffusion. PDT with locally administered aHP showed a higher anti-tumor effect after light irradiation at 635 nm for three days compared to low-molecular-weight HP. Intraperitoneal administration of HP caused severe phototoxicity upon irradiation with ultraviolet A at 10 J cm-2, whereas aHP did not cause phototoxicity because its diffusion into the skin could be suppressed, probably due to the high-molecular weight of aHP. Therefore, locally administered PDT with aHP is a potential PDT having high therapeutic efficacy without phototoxicity.

Polymer nanomaterials for use as adjuvant surgical tools

Materials employed in the treatment of conditions encountered in surgical and clinical practice frequently face barriers in translation to application. Shortcomings can be generalized through their reduced mechanical stability, difficulty in handling, and inability to conform or adhere to complex tissue surfaces. To overcome an amalgam of challenges, research has sought the utilization of polymer-derived nanomaterials deposited in various fashions and formulations to improve the application and outcomes of surgical and clinical interventions. Clinically prevalent applications include topical wound dressings, tissue adhesives, surgical sealants, hemostats, and adhesion barriers, all of which have displayed the potential to act as superior alternatives to current materials used in surgical procedures. In this review, emphasis will be placed not only on applications, but also on various design strategies employed in fabrication. This review is designed to provide a broad and thought-provoking understanding of nanomaterials as adjuvant tools for the assisted treatment of pathologies prevalent in surgery. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Implantable Materials and Surgical Technologies > Nanoscale Tools and Techniques in Surgery.

A Prospective Comparison of Octyl-2-Cyanoacrylate and Suture in Facial Wounds

The study aimed to evaluate the efficacy of octyl-2-cyanoacrylate as well as sutures as a wound closure material. Whether octyl-2-cyanoacrylate can be used as an alternative to suture in the closure of facial wounds. Out of total of 19 wounds, 11 wounds were closed with sutures and tissue adhesive both, out of rest 8 wounds, 4 wounds were closed using sutures alone and in 4 wounds, closure was done with tissue adhesive alone. Therefore, a total of 15 facial wounds were divided into two groups: Group-I Cases in whom 3-0 Black silk suture was used for closure of the wound and Group-II Cases in whom Dermabond (Octyl-2-Cyanoacrylate) was used for closure of the wound. Results showed that Octyl-2-cyanoacrylate offered the benefit of decreased procedure time with less pain, no need for its removal, and better cosmetic outcome compared to sutures.

Fermentation-Derived Albumin-Based Hydrogels for Tissue Adhesion Applications

Currently, most of the clinically available surgical glues and sealants lack elasticity, good adhesion and biocompatibility properties. Hydrogels as tissue adhesives have received extensive attention for their tissue-mimicking features. Here, a novel surgical glue hydrogel based on a fermentation-derived human albumin (rAlb) and biocompatible crosslinker for tissue-sealant applications has been developed. In order to reduce the risks of viral transmission diseases and an immune response, Animal-Free Recombinant Human Albumin from the saccharomyces yeast strain was used. A more biocompatible crosslinking agent, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC), was used and compared with glutaraldehyde (GA). The design of crosslinked albumin-based adhesive gels was optimized by varying the albumin concentration, the mass ratio between albumin and the crosslinking agent as well as the crosslinker type. Tissue sealants were characterized in terms of mechanical (tensile and shear), adhesive and in vitro biocompatibility properties. The results indicated that the mechanical and adhesive properties improved as the albumin concentration increased and the mass ratio between albumin and crosslinker decreased. Moreover, the EDC-crosslinked albumin gels have better biocompatibility properties than GA-crosslinked glues.

Tissue Adhesive, Biocompatible, Antioxidant, and Antibacterial Hydrogels Based on Tannic Acid and Fungal-Derived Carboxymethyl Chitosan for Wound-Dressing Applications

This study aimed to develop hydrogels for tissue adhesion that are biocompatible, antioxidant, and antibacterial. We achieved this by using tannic acid (TA) and fungal-derived carboxymethyl chitosan (FCMCS) incorporated in a polyacrylamide (PAM) network using free-radical polymerization. The concentration of TA greatly influenced the physicochemical and biological properties of the hydrogels. Scanning electron microscopy showed that the nanoporous structure of the FCMCS hydrogel was retained with the addition of TA, resulting in a nanoporous surface structure. Equilibrium-swelling experiments revealed that increasing the concentration of TA significantly improved water uptake capacity. Antioxidant radical-scavenging assays and porcine skin adhesion tests confirmed the excellent adhesive properties of the hydrogels, with adhesion strengths of up to 39.8 ± 1.2 kPa for 1.0TA-FCMCS due to the presence of abundant phenolic groups on TA. The hydrogels were also found to be biocompatible with skin fibroblast cells. Furthermore, the presence of TA significantly enhanced the antibacterial properties of the hydrogels against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Therefore, the developed drug-free antibacterial and tissue-adhesive hydrogels can potentially be used as wound dressings for infected wounds.

Dynamic Crosslinked Injectable Mussel-Inspired Hydrogels with Adhesive, Self-Healing, and Biodegradation Properties

The non-invasive tissue adhesives with strong tissue adhesion and good biocompatibility are ideal for replacing traditional wound treatment methods such as sutures and needles. The self-healing hydrogels based on dynamic reversible crosslinking can recover their structure and function after damage, which is suitable for the application scenario of tissue adhesives. Herein, inspired by mussel adhesive proteins, we propose a facile strategy to achieve an injectable hydrogel (DACS hydrogel) by grafting dopamine (DOPA) onto hyaluronic acid (HA) and mixing it with carboxymethyl chitosan (CMCS) solution. The gelation time and rheological and swelling properties of the hydrogel can be controlled conveniently by adjusting the substitution degree of the catechol group and the concentration of raw materials. More importantly, the hydrogel exhibited rapid and highly efficient self-healing ability and excellent biodegradation and biocompatibility in vitro. Meanwhile, the hydrogel exhibited ~4-fold enhanced wet tissue adhesion strength (21.41 kPa) over the commercial fibrin glue. This kind of HA-based mussel biomimetic self-healing hydrogel is expected to be used as a multifunctional tissue adhesive material.

Controlled Release of a Therapeutic Peptide in Sprayable Surgical Sealant for Prevention of Postoperative Abdominal Adhesions

Formation of asymmetric, rigid scar tissue known as surgical adhesions is caused by traumatic disruption of mesothelial-lined surfaces in surgery. A widely adopted prophylactic barrier material (Seprafilm) for the treatment of intra-abdominal adhesions is applied operatively as a pre-dried hydrogel sheet but has reduced translational efficacy due its brittle mechanical properties. Topically administered peritoneal dialysate (Icodextrin) and anti-inflammatory drugs have failed to prevent adhesions due to an uncontrolled release profile. Hence, inclusion of a targeted therapeutic into a solid barrier host matrix with improved mechanical properties could provide dual utility in adhesion prevention and as a surgical sealant. Spray deposition of poly(lactide-co-caprolactone) (PLCL) polymer fibers through solution blow spinning has yielded a tissue-adherent barrier material with previously reported adhesion prevention efficacy due to a surface erosion mechanism that inhibits deposition of inflamed tissue. However, such an approach uniquely presents an avenue for controlled therapeutic release through mechanisms of diffusion and degradation. Such a rate is kinetically tuned via facile blending of "high" molecular weight (HMW) and "low" molecular weight (LMW) PLCL with slow and fast biodegradation rates, respectively. Here, we explore viscoelastic blends of HMW PLCL (70% w/v) and LMW PLCL (30% w/v) as a host matrix for anti-inflammatory drug delivery. In this work, COG133, an apolipoprotein E (ApoE) mimetic peptide with potent anti-inflammatory properties was selected and tested. In vitro studies with PLCL blends presented low (∼30%) and high (∼80%) percent release profiles over a 14-day period based on the nominal molecular weight of the HMW PLCL component. Two independent mouse models of cecal ligation and cecal anastomosis significantly reduced adhesion severity versus Seprafilm, COG133 liquid suspension, and no treatment control. The synergy of physical and chemical methods in a barrier material with proven preclinical studies highlights the value of COG133-loaded PLCL fiber mats in effectively dampening the formation of severe abdominal adhesions.

Temporal evaluation of efficacy and quality of tissue repair upon laser-activated sealing

Injuries caused by surgical incisions or traumatic lacerations compromise the structural and functional integrity of skin. Immediate approximation and robust repair of skin are critical to minimize occurrences of dehiscence and infection that can lead to impaired healing and further complication. Light-activated skin sealing has emerged as an alternative to sutures, staples, and superficial adhesives, which do not integrate with tissues and are prone to scarring and infection. Here, we evaluate both shorter- and longer-term efficacy of tissue repair response following laser-activated sealing of full-thickness skin incisions in immunocompetent mice and compare them to the efficacy seen with sutures. Laser-activated sealants (LASEs) in which, indocyanine green was embedded within silk fibroin films, were used to form viscous pastes and applied over wound edges. A hand-held, near-infrared laser was applied over the incision, and conversion of the light energy to heat by the LASE facilitated rapid photothermal sealing of the wound in approximately 1 min. Tissue repair with LASEs was evaluated using functional recovery (transepidermal water loss), biomechanical recovery (tensile strength), tissue visualization (ultrasound [US] and photoacoustic imaging [PAI]), and histology, and compared with that seen in sutures. Our studies indicate that LASEs promoted earlier recovery of barrier and mechanical function of healed skin compared to suture-closed incisions. Visualization of sealed skin using US and PAI indicated integration of the LASE with the tissue. Histological analyses of LASE-sealed skin sections showed reduced neutrophil and increased proresolution macrophages on Days 2 and 7 postclosure of incisions, without an increase in scarring or fibrosis. Together, our studies show that simple fabrication and application methods combined with rapid sealing of wound edges with improved histological outcomes make LASE a promising alternative for management of incisional wounds and lacerations.

Evaluation of Incisional Wound Healing in Dogs after Closure with Staples or Tissue Glue and Comparison to Intradermal Suture Pattern

The study aimed to monitor the healing process in the canine skin following surgical incision and closure using staples or tissue glue and to compare them with the intradermal suture pattern. Surgically created skin incisions in 10 dogs were apposed with staples, tissue glue (n-butyl cyanoacrylate) and continuous intradermal pattern. The cosmetic appearance of the wounds was blindly evaluated on days 7, 14 and 28 and once a month until the end of the experiment, i.e., one year after the incision. Ultrasonographic and clinical evaluation was performed on days 0-10, 12, 14, 16, 18, 21, 24 and 28, once a week until the end of the 3rd month and once a month until the end of the experiment. Histopathological evaluation was performed on days 7, 14, 28, 180 and 365. The median time required for the performance of each technique differed significantly between techniques; stapling lasted 21 s, glue 2 min 16 s and intradermal 15 min 37 s. Cosmetic appearance with glue was statistically worse than staples and intradermal. The clinical appearance of intradermal was significantly better than glue and staples. No significant differences were found at histological evaluation; however, glue had the worst score throughout the experiment. The overall evaluation of the techniques showed that glue had the worst score compared to intradermal and staples, with the difference being statistically significant in the first postoperative week. Intradermal suture pattern is much better than glue application for skin closure in dogs, whilst is not significantly better than staples. Staples should be preferred when time is an important factor.

Short peripheral intravenous catheter securement with cyanoacrylate glue compared to conventional dressing: A randomized controlled trial

BACKGROUND

Short peripheral intravenous catheters (PIVCs) fail prior to completion of therapy in up to 63% of hospitalizations. This unacceptably high rate of failure has become the norm for the most common invasive procedure in all of medicine. Securement strategies may improve PIVC survival.

METHODS

We conducted a prospective, single-site, parallel, two-arm randomized controlled investigation with a primary outcome of catheter failure comparing securement with standard semi-permeable dressing and clear tape (SPD) to standard semipermeable dressing and clear tape with cyanoacrylate glue (SPD + CG). Adult emergency department patients with a short PIVC and anticipated hospital duration ⩾ 48 h were enrolled and followed until IV failure or completion of therapy for up to 7 days. Secondary outcomes included complications and cost comparisons between groups. Primary outcome was assessed by intention to treat and per protocol analyses.

FINDINGS

350 patients were enrolled between November 2019 and October 2020. PIVC survival for SPD + CG was similar to SPD group with the absolute risk difference of IV failure in the intention-to-treat (-5.8%, p = 0.065) population and improved in the per protocol (-8.1%, p = 0.04) population, respectively. Kaplan-Meier survival analysis indicated there was a significant benefit of the SPD + CG at greater than 2 days of hospitalization (p = 0.04). Prior to 48 h, there was no survival enhancement to either group (p = 0.98) in the intention to treat population. In a multivariable analysis with piecewise Cox regression, when the IV was functional greater than 48 h, the risk of IV failure in the SPD + CG was 43% less than the SPD group (adjusted hazard ratio [HR] 0.57, 95% confidence interval [CI] 0.34 to 0.97; p = 0.04). Cumulative cost related to IV during hospitalization was similar between groups with a lower incremental rescue cost in the SPD + CG group.

INTERPRETATION

SPD combined with cyanoacrylate glue provides similar benefit to patients compared to SPD alone and potentially improves short PIVC survival when the IV was inserted >48 h. As this strategy is cost neutral, it could be considered in admitted patients, particularly those with longer anticipated hospital durations.

Attached Oral Mucosal Wound Closure using Blue Glue - A Prospective Clinical Study

Introduction

Traditionally, sutures have been widely used to close intraoral wounds. Various alternatives have been developed amongst which newer tissue adhesives such as N-butyl-2-cyanoacrylate having accepted clinical properties are gaining popularity. The primary purpose of the present study is to evaluate the efficacy of N-butyl-2-cyanoacrylate for intraoral attached mucosal wound closure following alveoloplasty.

Materials and Methods

In this prospective split-mouth study, 25 patients requiring alveoloplasty in either maxillary or mandibular arch bilaterally with a total of 50 sites were divided into two equal groups, namely silk suture (Group 1) and cyanoacrylate (Group 2). Each patient was evaluated on the first, third, seventh, 14th and 21st post-operative days. Parameters evaluated were time taken to close incision and to achieve haemostasis, pain, oedema, post-operative wound healing, patient discomfort and possible complications.

Results

Time taken to close incision, time taken to achieve haemostasis, post-operative pain and oedema were found to be less in Group 2. Wound healing too was found to be better in Group 2. There was one case of adhesive peel off on the first post-operative day which was managed by reapplying the tissue adhesive. The incidence of wound dehiscence and wound infection was observed more in Group 1 on the third post-operative day. Suture breakage (16%) and adhesive dislodgement (8%) were reported on the seventh post-operative day.

Discussion

The use of cyanoacrylates' inherent benefits, such as improved wound seal off in attached mucosa, quick polymerisation and bacteriostatic characteristics can be beneficial when performing minor oral surgical procedures on elderly, young and mentally challenged patients.

Regulation of the Inevitable Water-Responsivity of Silk Fibroin Biopolymer by Polar Amino Acid Activation

In nature, water is vital for maintaining homeostasis. Particularly, organisms (e.g., plant leaf, bird feather) exploit water fluidics for motions. Hydration-adaptive crystallization is the representative water-responsive actuation of biopolymers. This crystallization has inspired the development of intelligent human-robot interfaces. At the same time, it hinders the consistent adhesion of tissue adhesive. As hydration-adaptive crystallization is inevitable, the on-demand control of crystallization is desirable in the innovative biopolymeric biomedical systems. To this end, this study developed an amino acid-based technology to artificially up- or down-regulate the inevitable crystallization of silk fibroin. A case II diffusion model was constructed, and it revealed that the activity of polar amino acid is related to crystallization kinetics. Furthermore, the water dynamics study suggested that active amino acid stabilizes crystallization-triggering water molecules. As a proof-of-concept, we verified that a 30% increase in the activity of serine resulted in a 50% decrease in the crystallization rate. Furthermore, the active amino acid-based suppression of hydration-adaptive crystallization enabled the silk fibroin to keep its robust adhesion (approximately 160 kJ m^-3) by reducing the water-induced loss of adhesive force. The proposed silk fibroin was demonstrated as a stable tissue adhesive applied on ex vivo porcine mandible tissue. This amino acid-based regulation of hydration-adaptive crystallization will pioneer next-generation biopolymer-based healthcare.

Surgical Management of Peripheral Ulcerative Keratitis: Update on Surgical Techniques and Their Outcome

Peripheral ulcerative keratitis (PUK) is an inflammatory, necrotic condition in the peripheral cornea which may end in corneal perforation and visual morbidity if not treated adequately. PUK can occur due to infectious or non-infectious causes. Early cases need medical therapy, both locally and systemically (for some cases). However, advanced PUK may necessitate surgical removal of inciting cause of the pathology and maintaining tectonic stability. Such surgical treatment, including corneal transplantations, may be used in an emergency setting or for visual rehabilitation following preliminary stabilization of the affected cornea. The outcome of these surgeries need to be analyzed to understand the long-term visual prognosis of such eyes. This is an attempt to analyze surgical modalities in the management of PUK and their outcomes.

Effects of Radiation on Cross-Linking Reaction, Microstructure, and Microbiological Properties of Whey Protein-Based Tissue Adhesive Development

Whey proteins are mainly a group of small globular proteins. Their structures can be modified by physical, chemical, and other means to improve their functionality. The objectives of this study are to investigate the effect of radiation on protein−protein interaction, microstructure, and microbiological properties of whey protein−water solutions for a novel biomaterial tissue adhesive. Whey protein isolate solutions (10%, 27%, 30%, 33%, and 36% protein) were treated by different intensities (10−35 kGy) of gamma radiation. The protein solutions were analyzed for viscosity, turbidity, soluble nitrogen, total plate count, and yeast and mold counts. The interactions between whey proteins were also analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and scanning electron microscopy. The viscosity of protein solution (27%, w/w) was increased by the treatment of gamma radiation and by the storage at 23 °C. The 35 kGy intensity irradiated soluble nitrogen (10%, w/w) was reduced to about half of the sample treated by 0 kGy gamma radiation. The effects of gamma radiation and storage time can significantly increase the viscosity of whey protein solutions (p < 0.05). Radiation treatment had significant impact on soluble nitrogen of whey protein solutions (p < 0.05). SDS-PAGE results show that the extent of oligomerization of whey protein isolate solutions are increased by the enhancement in gamma radiation intensity. Photographs of SEM also indicate that protein−protein interactions are induced by gamma radiation in the model system. Consistent with above results, the bonding strength increases by the addition of extent of gamma radiation and the concentration of glutaraldehyde. Our results revealed that the combination of gamma-irradiated whey protein isolate solutions and glutaraldehyde can be used as a novel biomaterial tissue adhesive.

Sprayable tissue adhesive with biodegradation tuned for prevention of postoperative abdominal adhesions

Adhesions are dense, fibrous bridges that adjoin tissue surfaces due to uncontrolled inflammation following postoperative mesothelial injury. A widely used adhesion barrier material in Seprafilm often fails to prevent transverse scar tissue deposition because of its poor mechanical properties, rapid degradation profile, and difficulty in precise application. Solution blow spinning (SBS), a polymer fiber deposition technique, allows for the placement of in situ tissue-conforming and tissue-adherent scaffolds with exceptional mechanical properties. While biodegradable polymers such as poly(lactic-co-glycolic acid) (PLGA) have desirable strength, they exhibit bulk biodegradation rates and inflammatory profiles that limit their use as adhesion barriers and result in poor tissue adhesion. Here, viscoelastic poly(lactide-co-caprolactone) (PLCL) is used for its pertinent biodegradation mechanism. Because it degrades via surface erosion, spray deposited PLCL fibers can dissolve new connections formed by inflamed tissue, allowing them to function as an effective, durable, and easy-to-apply adhesion barrier. Degradation kinetics are tuned to match adhesion formation through the design of PLCL blends comprised of highly adhesive "low"-molecular weight (LMW) constituents in a mechanically robust "high"-molecular weight (HMW) matrix. In vitro studies demonstrate that blending LMW PLCL (30% w/v) with HMW PLCL (70% w/v) yields an anti-fibrotic yet tissue-adhesive polymer sealant with a 14-day erosion rate countering adhesion formation. PLCL blends additionally exhibit improved wet tissue adhesion strength (~10 kPa) over a 14-day period versus previously explored biodegradable polymer compositions, such as PLGA. In a mouse cecal ligation model, select PLCL blends significantly reduce abdominal adhesions severity versus no treatment and Seprafilm-treated controls.

Long-Term Fluorescent Tissue Marking Using Tissue-Adhesive Porphyrin with Polycations Consisting of Quaternary Ammonium Salt Groups

Localization of tumors during laparoscopic surgery is generally performed by locally injecting India ink into the submucosal layer of the gastrointestinal tract using endoscopy. However, the location of the tumor is obscured because of the black-stained surgical field and the blurring caused by India ink. To solve this problem, in this study, we developed a tissue-adhesive porphyrin with polycations consisting of quaternary ammonium salt groups. To evaluate the ability of tissue-adhesive porphyrin in vivo, low-molecular-weight hematoporphyrin and tissue-adhesive porphyrin were injected into the anterior wall of the exposed stomach in rats. Local injection of low-molecular-weight hematoporphyrin into the anterior wall of the stomach was not visible even after 1 day because of its rapid diffusion. In contrast, the red fluorescence of the tissue-adhesive porphyrin was visible even after 7 days due to the electrostatic interactions between the positively-charged moieties of the polycation in the tissue-adhesive porphyrin and the negatively-charged molecules in the tissue. In addition, intraperitoneal injection of tissue-adhesive porphyrin in rats did not cause adverse effects such as weight loss, hepatic or renal dysfunction, or organ adhesion in the abdominal cavity. These results indicate that tissue-adhesive porphyrin is a promising fluorescent tissue-marking agent.

Current Concepts on Tissue Adhesive Use for Meniscal Repair-We Are Not There Yet: A Systematic Review of the Literature

BACKGROUND

Tissue adhesives (TAs) represent a promising alternative or augmentation method to conventional tissue repair techniques. In sports medicine, TA use has been suggested and implemented in the treatment of meniscal tears. The aim of this review was to present and discuss the current evidence and base of knowledge regarding the clinical usage of TAs for meniscal repair.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic literature search was performed using the PubMed, Embase, and Cochrane Library databases for studies reporting on clinical outcomes of TA usage for meniscal repair in humans in the English language published before January 2020.

RESULTS

Ten studies were eligible for review and included 352 meniscal repairs: 94 (27%) were TA-based repairs and 258 (73%) were combined suture and TA repairs. Concomitant anterior cruciate ligament reconstruction was performed in 224 repairs (64%). All included studies utilized fibrin-based TA. Of the 10 studies, 9 were evidence level 4 (case series), and 8 reported on a cohort of ≤40 meniscal repairs. Rates of meniscal healing were evaluated in 9 of 10 studies, with repair failure seen in 39 repairs (11%).

CONCLUSION

The use of TAs, specifically fibrin-based TAs, for meniscal repair shows good results as either an augmentation or primary repair of various configurations of meniscal tears. However, this review reveals an absence of comparative high-quality evidence supporting the routine use of TAs for meniscal repair and emphasizes the lack of an ideal TA designed for that purpose. Further high-quality research, basic science and clinical, will facilitate the development of new materials and enable testing their suitability for use in meniscal repair.

Multi-crosslinked hydrogels with instant self-healing and tissue adhesive properties for biomedical applications

Due to the defects like long gelling time, inferior mechanical properties and weak adhesion, in-situ forming hydrogels are still restricted in biomedical applications like viscera rupture and targeted therapy. To address these problems, a new kind of multi-crosslinked hydrogel (G-OKG-DA) consisting of gelatin, oxidized konjac glucomannan (OKG), and dopamine (DA) is proposed in this study. The resulting hybrid hydrogel is endowed with a short gelling time (about 3 min) and injectable capacity. According to the mechanical and adhesive tests, G-OKG-DA hydrogel shows a robust tensile strength of 23.94 kPa, as well as a higher adhesive strength (around 150 kPa) than commercial fibrin glue. In addition, an instant self-healing behavior of G-OKG-DA hydrogel can be found, which is attributed to multi-crosslinking reactions including Schiff-base dynamic covalent bonds between OKG and gelatin, oxidative polymerization of DA, and catechol-mediated chemistry like Michael addition and DA-quinone coupling. Importantly, the multi-crosslinked hydrogel will not compromise its hemocompatibility and cytocompatibility in vitro, suggesting potential applications in biomedical fields as tissue adhesive and implants. This article is protected by copyright. All rights reserved.

Facile Preparation of Tunicate-Inspired Chitosan Hydrogel Adhesive with Self-Healing and Antibacterial Properties

In order to replace traditional wound treatments such as sutures, tissue adhesives with strong wet tissue adhesion and biocompatibility have attracted more attention to the applications of non-invasive wound closure. Herein, inspired by tunicate adhesive protein, a series of 2,3,4-trihydroxybenzaldehyde (TBA)-modified chitosan hydrogels (CS-TBA-Fe) were prepared by easily mixing the solutions of chitosan-FeCl₃ and TBA via the Schiff-base reaction and the coordination between Fe³⁺ and pyrogallol groups. The gelation time was greatly shortened to only several seconds after induced even trace Fe³⁺. The hydrogel (CS-TBA-Fe) exhibited ~12-fold enhanced wet tissue adhesion strength (60.3 kPa) over the commercial fibrin glue. Meanwhile, the hydrogel also showed robust adhesion to various substrates such as wood, PMMA, and aluminum. The swelling ratio and rheological property can be simply controlled by changing the concentrations of chitosan, TBA, and Fe³⁺. Moreover, the hydrogel displayed a rapid and highly efficient self-healing ability and an excellent antibacterial activity against E. coli. The overall results show that the CS-TBA-Fe hydrogel with enhanced wet adhesiveness will be a promising tissue adhesive material.

Biomimetic Joint Paint for Efficient Cartilage Repair by Simultaneously Regulating Cartilage Degeneration and Regeneration in Pigs

Irregular partial-thickness cartilage defect is a common pathogenesis of osteoarthritis (OA) with no available treatment in clinical practice. Currently, cartilage tissue engineering is only suitable for a limited area of full-thickness cartilage defect. Here, we design a biomimetic joint paint for the intractable partial-thickness cartilage defect repair. The joint paint, composed of a bridging layer of chondroitin sulfate and a surface layer of gelatin methacrylate with hyaluronic acid, can quickly and tightly adhere to the cartilage defect by light activation. Being treated by the joint paint, the group of rabbit and pig models with partial-thickness cartilage defects showed a restoration of a smooth cartilage surface and the preservation of normal glycosaminoglycan content, whereas the untreated control group exhibited serious progressive OA development. This paint treatment functions by prohibiting chondrocyte apoptosis, maintaining chondrocyte phenotype, and preserving the content of glycosaminoglycan in the partial-thickness cartilage defects. These findings illustrated that the biomimetic joint paint is an effective and revolutionary therapeutics for the patients with noncurable partial-thickness cartilage defects.

Skin hypersensitivity following application of tissue adhesive (2-octyl cyanoacrylate)

Tissue adhesives are commonly used for skin closure in both surgical and nonsurgical specialties. Although they are very well tolerated, tissue adhesives can induce a localized allergic response in 0.5% to 14% of patients. Allergic response can result in wound dehiscence, patient discomfort, increased healing time, and suboptimal esthetic results. We present two cases of allergic reaction to anterior neck incisions following topical application of tissue adhesives. The patients were managed with local wound care, steroid administration, and one with subsequent revision surgery. Clinicians who routinely use tissue adhesives should understand the incidence, risk factors, and management of allergic reaction to these products.

Tissue Adhesion-Anisotropic Polyrotaxane Hydrogels Bilayered with Collagen

Hydrogels are promising materials in tissue engineering scaffolds for healing and regenerating damaged biological tissues. Previously, we developed supramolecular hydrogels using polyrotaxane (PRX), consisting of multiple cyclic molecules threaded by an axis polymer for modulating cellular responses. However, since hydrogels generally have a large amount of water, their adhesion to tissues is extremely weak. Herein, we designed a bilayered hydrogel with a PRX layer and a collagen layer (PRX/collagen hydrogel) to achieve rapid and strong adhesion to the target tissue. The PRX/collagen hydrogel was fabricated by polymerizing PRX crosslinkers in water with placement of a collagen sponge. The differences in components between the PRX and collagen layers were analyzed using Fourier transform infrared spectroscopy (FT-IR). After confirming that the fibroblasts adhered to both layers of the PRX/collagen hydrogels, the hydrogels were implanted subcutaneously in mice. The PRX hydrogel without collagen moved out of its placement site 24 h after implantation, whereas the bilayer hydrogel was perfectly adherent at the site. Together, these findings indicate that the bilayer structure generated using PRX and collagen may be a rational design for performing anisotropic adhesion.

Strong, Multifaceted Guanidinium-Based Adhesion of Bioorganic Nanoparticles to Wet Biological Tissue

Gluing dynamic, wet biological tissue is important in injury treatment yet difficult to achieve. Polymeric adhesives are inconvenient to handle due to rapid cross-linking and can raise biocompatibility concerns. Inorganic nanoparticles adhere weakly to wet surfaces. Herein, an aqueous suspension of guanidinium-functionalized chitin nanoparticles as a biomedical adhesive with biocompatible, hemostatic, and antibacterial properties is developed. It glues porcine skin up to 3000-fold more strongly (30 kPa) than inorganic nanoparticles at the same concentration and adheres at neutral pH, which is unachievable with mussel-inspired adhesives alone. The glue exhibits an instant adhesion (2 min) to fully wet surfaces, and the glued assembly endures one-week underwater immersion. The suspension is lowly viscous and stable, hence sprayable and convenient to store. A nanomechanic study reveals that guanidinium moieties are chaotropic, creating strong, multifaceted noncovalent bonds with proteins: salt bridges comprising ionic attraction and bidentate hydrogen bonding with acidic moieties, cation-π interactions with aromatic moieties, and hydrophobic interactions. The adhesion mechanism provides a blueprint for advanced tissue adhesives.

[Surgical management of infectious keratitis]

Infectious keratitis is one of the most common causes of blindness worldwide. Despite the existence of a wide arsenal of quite effective antimicrobial drugs, some forms of bacterial and viral keratitis are resistant. Advanced acanthamoeba and mycotic lesions of the cornea, as well as mixed forms of infection usually do not respond well to conservative treatment. In the absence of positive dynamics from the applied etiotropic therapy with observed further progression of the microbial process, there is a risk of corneal perforation and spread of infection to the sclera or deep ocular structures with a high probability of irreversible functional disorders or anatomical death of the eye. In such cases, a timely transition to surgical treatment is necessary in order to maintain structural integrity of the eyeball. For this purpose, corneal crosslinking, microdiathermocoagulation, tissue adhesive, autoconjunctival plasty, amniotic membrane, corneoscleral flap coating, various combinations of these methods, as well as therapeutic keratoplasty are used most often in clinical practice. The choice depends on the etiology, size and depth of the lesion, its localization, prognosis of visual outcomes, somatic status of the patient. Therapeutic keratoplasty is the most radical and effective method of surgical intervention that allows eradication of the infectious focus and best possible restoration of the structural integrity of the eyeball. However, in some cases due to inaccessibility of donor material or high risks of the surgery and non-transparent graft engraftment, it is advised to use alternative surgical approaches, and keratoplasty, if necessary, should be carried out for optical purposes at a further, "quiet" period.

Mussel-Inspired Bisphosphonated Injectable Nanocomposite Hydrogels with Adhesive, Self-Healing, and Osteogenic Properties for Bone Regeneration

Injectable hydrogels have received much attention because of the advantages of simulation of the natural extracellular matrix, microinvasive implantation, and filling and repairing of complex shape defects. Yet, for bone repair, the current injectable hydrogels have shown significant limitations such as the lack of tissue adhesion, deficiency of self-healing ability, and absence of osteogenic activity. Herein, a strategy to construct mussel-inspired bisphosphonated injectable nanocomposite hydrogels with adhesive, self-healing, and osteogenic properties is developed. The nano-hydroxyapatite/poly(l-glutamic acid)-dextran (nHA/PLGA-Dex) dually cross-linked (DC) injectable hydrogels are fabricated via Schiff base cross-linking and noncovalent nHA-BP chelation. The chelation between bisphosphonate ligands (alendronate sodium, BP) and nHA favors the uniform dispersion of the latter. Moreover, multiple adhesion ligands based on catechol motifs, BP, and aldehyde groups endow the hydrogels with good tissue adhesion. The hydrogels possess excellent biocompatibility and the introduction of BP and nHA both can effectively promote viability, proliferation, migration, and osteogenesis differentiation of MC3T3-E1 cells. The incorporation of BP groups and HA nanoparticles could also facilitate the angiogenic property of endothelial cells. The nHA/PLGA-Dex DC hydrogels exhibited considerable biocompatibility despite the presence of a certain degree of inflammatory response in the early stage. The successful healing of a rat cranial defect further proves the bone regeneration ability of nHA/PLGA-Dex DC injectable hydrogels. The developed tissue adhesive osteogenic injectable nHA/PLGA-Dex hydrogels show significant potential for bone regeneration application.

Novel Diabetic Foot Wound Dressing Based on Multifunctional Hydrogels with Extensive Temperature-Tolerant, Durable, Adhesive, and Intrinsic Antibacterial Properties

Diabetic foot ulcers (DFUs) are hard-healing chronic wounds and susceptible to bacterial infection. Conventional hydrogel dressings easily lose water at high temperature or freeze at low temperature, making them unsuitable for long-term use or in extreme environments. Herein, a temperature-tolerant (-20 to 60 °C) antibacterial hydrogel dressing is fabricated by the assembly of polyacrylamide, gelatin, and ε-polylysine. Owing to the water/glycerin (Gly) binary solvent system, the resultant hydrogel (G-PAGL) displayed good heat resistance and antifreezing properties. Within the wide temperature range (-20 to 60 °C), all the desirable features of the hydrogel, including superstretchability (>1400%), enduring water retention, adhesiveness, and persistent antibacterial property, are quite stable. Remarkably, the hydrogel wound dressing displayed lasting and broad antibacterial activity against Gram-positive and Gram-negative bacteria. Satisfactorily, the double-network (DN) G-PAGL hydrogel dressing could effectively promote the healing of DFUs by accelerating collagen deposition, promoting angiogenesis, and inhibiting bacterial breed. As far as we know, this is the first time that the extensive temperature-tolerant DN hydrogel with antibacterial ability is developed to use as DFU wound dressing. The G-PAGL hydrogel provides more choices for DFU wound dressings that could be used in extreme environments.

Endoscopic obturation with tissue adhesive for bleeding gastric stromal tumor: a case report

Primary endoscopic hemostasis for bleeding gastrointestinal stromal tumor (GIST) is rarely reported. Herein, we report the case of a patient with a bleeding GIST that was treated with endoscopic obturation with tissue adhesive. A 46-year-old man presented with hematemesis and tarry stool for 1 day. Upper GI endoscopy revealed a bleeding submucosal tumor at the stomach fundus and an exposed pulsatile vessel was seen at the defect. Endoscopic obturation with tissue adhesive was performed to treat the defect and the bleeding was successfully stopped. No recurrence of bleeding was observed through a gastric tube, and 6 days after endoscopic obturation, the patient underwent laparoscopic partial gastrectomy. Endoscopic obturation with tissue adhesive is a feasible and effective method to treat bleeding GIST.

Efficacy evaluation of anin situforming tissue adhesive hydrogel as sealant for lung and vascular injury

In situforming tissue adhesives based on biopolymers offer advantages over conventional sutures and staples in terms of biocompatibility, biodegradability, ease of application and improved patient compliance and comfort. Here, we describe the evaluation ofin situgelling hydrogel system based on dextran dialdehyde (DDA) obtained by periodate oxidization of dextran and chitosan hydrochloride (CH) as tissue adhesive. The hydrogel was prepared by reacting aldehyde functions in DDA with the amino functions in CH via Schiff's reaction. The gelation reaction was instantaneous and took just 4 s. The DDA-CH hydrogel as tissue adhesive was evaluated on a sheep lung parenchymal injury model and a pig aortic model and was compared with the commercially available tissue sealant, Bioglue®. The DDA-CH glue could completely seal the sheep lung incision site even at inflation with air way pressure of 30 cm of H₂O with no air leak observed in the incision sites (n= 8) in any of the animals. Histological analyses showed mild inflammation after 2 weeks, comparable to Bioglue®. Resorption of test material by giant cells with no adverse effect on lung parenchyma was seen after 3 months. The DDA-CH glue was also very effective in sealing aortic incisions in a pig model (n= 4) with no failures and aneurisms. The endoluminal surface of the sealed incision in all cases showed intact apposition with adequate healing across the incision. No tissue necrosis or inflammation of endothelial surface could be seen grossly. Our studies show that the DDA-CH hydrogel could function as an effective sealant for the prevention of air and blood leaks following lung and vascular surgery.

Robust Hydrogel Adhesive with Dual Hydrogen Bond Networks

Hydrogel adhesives are attractive for applications in intelligent soft materials and tissue engineering, but conventional hydrogels usually have poor adhesion. In this study, we designed a strategy to synthesize a novel adhesive with a thin hydrogel adhesive layer integrated on a tough substrate hydrogel. The adhesive layer with positive charges of ammonium groups on the polymer backbones strongly bonds to a wide range of nonporous materials’ surfaces. The substrate layer with a dual hydrogen bond system consists of (i) weak hydrogen bonds between N,N-dimethyl acrylamide (DMAA) and acrylic acid (AAc) units and (ii) strong multiple hydrogen bonds between 2-ureido-4[1H]-pyrimidinone (UPy) units. The dual hydrogen-bond network endowed the hydrogel adhesives with unique mechanical properties, e.g., toughness, highly stretchability, and insensitivity to notches. The hydrogel adhesion to four types of materials like glass, 316L stainless steel, aluminum, Al₂O₃ ceramic, and two biological tissues including pig skin and pig kidney was investigated. The hydrogel bonds strongly to dry solid surfaces and wet tissue, which is promising for biomedical applications.

A novel technique for preoperative localization of pulmonary nodules using a mixture of tissue adhesive and iohexol under computed tomography guidance: A 140 patient single-center study

Background

The increase in the incidence of pulmonary nodules has made computed tomography (CT) screening a requirement for diagnosis and treatment. Small pulmonary nodule detection during video‐assisted thoracoscopic surgery (VATS) or thoracotomy is frequently challenging; however, accurate and efficient localization of nodules is critical for precise resection. Herein, we introduce and evaluate the feasibility and safety of a novel technique for preoperative pulmonary nodule localization.

Methods

From March 2018 to December 2019, 140 patients with 153 pulmonary nodules measuring <2 cm in diameter were enrolled in this study. Preoperative, CT‐guided localization was performed on each nodule with an injected mixture of tissue adhesive and iohexol. Patient and nodule characteristics, localization data, complications, surgical data, and pathological results were analyzed.

Results

All 153 nodules in 140 patients were successfully marked preoperatively and detected during surgery (n = 153/153). Mean nodule size was 8.7 ± 2.6 mm, and mean distance from nodule to pleura was 7.9 ± 8.2 mm. The mean procedural time was 8.7 ± 1.0 min. Nine patients (6.4%) underwent two simultaneous nodule localizations and two patients (1.4%) underwent three simultaneous nodule localizations. Pneumothorax (17/140, 12.1%), pain (6/140, 4.3%), and pungent odor (5/140, 3.6%) were the major complications. No patient required further treatment, and no allergic reactions or embolisms were observed.

Conclusions

Preoperative CT‐guided nodule localization using a mixture of tissue adhesive and iohexol is an efficient technique for localizing small and impalpable pulmonary lesions, including multiple pulmonary nodules. Our study demonstrates that this novel method is safe and straightforward to implement.

Development of Acquired Factor V Inhibitor After Surgical Procedure Without the Use of Fibrin Tissue Adhesives: A Case Report

Development of acquired factor V (FV) inhibitor is a rare coagulation disorder. Production of heteroantibodies against bovine FV, a contaminant in fibrin tissue adhesives, is a common cause of this condition in the field of surgery. The development of recombinant thrombin eliminated contamination of bovine FV, and infrequent use of bovine thrombin has decreased the risk of FV inhibitor development. Here, we report the case of a 43-year-old man who had marked prolongation of prothrombin time and activated partial thromboplastin time after surgery. Mixing coagulation studies with normal plasma and patient’s plasma suggested the presence of an inhibitor. Clotting factor assays revealed that FV activity decreased to <1% with positive FV inhibitor titer (9.2 Bethesda units). The diagnosis of the FV inhibitor was confirmed. Overt bleeding was not observed during the course of hospitalization. His coagulation abnormalities rapidly normalized without any medical intervention. A careful review of his medical records revealed that no tissue adhesives were used in the patient, and the FV inhibitor would likely be autoantibodies. Antibiotic use during the perioperative period or the surgical procedure itself may trigger the occurrence of FV inhibitors. This case highlights that FV inhibitor may develop after the surgical procedure even without a history of the use of fibrin tissue adhesives. Surgeons and hematologists should be aware that this rare but potentially life-threatening condition may occur after the surgical procedure.

Allergic contact dermatitis due to the liquid skin adhesive Dermabond® predominantly occurs after the first exposure

BACKGROUND

The clinical characteristics of patients with allergic contact dermatitis (ACD) due to a skin adhesive containing 2-octyl cyanoacrylate, Dermabond®, have not yet been elucidated.

OBJECTIVE

To investigate the clinical characteristics of patients with ACD caused by Dermabond® application.

METHODS

In this retrospective study, 577 patch tested patients were included. We identified patients with positive patch test results for Dermabond® and evaluated their results concerning (meth)acrylates and ethyl cyanoacrylate adhesive.

RESULTS

Nine patients had positive patch test results to Dermabond®; six had developed secondary generalization.The mean time between Dermabond® application and ACD onset was 34 days (range, 27-44) in six patients with ACD after the first use, whereas, in the other three patients, it was 5.6 days (range, 4-8) after the second use. The time was significantly different between the two groups (P < .01). Positive reactions to ethyl cyanoacrylate adhesive (Aron Alpha) occurred in seven of nine patients, to ethyl cyanoacrylate 10% pet. in four of eight patients tested, and to 2-hydroxyethyl methacrylate in one of eight patients tested.

CONCLUSIONS

Dermabond®-induced ACD is apparently characterized by a high prevalence of primary sensitization at first exposure to Dermabond®, secondary generalization is frequent, and most patients show cross-reactivity to ethyl cyanoacrylate.

A Prospective, Randomized and Controlled Study on Tissue Adhesive for Skin Incision in Total Knee Arthroplasty

Background

The study focusing on the tissue adhesive in total knee arthroplasty (TKA) was rare. This study aimed to evaluate the clinical outcomes and economic costs of tissue adhesive when acting as the adjunct to standard incision closure in TKA.

Patients and Methods

From September 2019 to November 2019, we prospectively enrolled the consecutive patients who underwent simultaneous bilateral TKA in our institute. The allocation using the tissue adhesive was done after the subcuticular suture in right knee first and another method was applied in the left knee automatically. The patients’ demographics, length of stay (LOS), times of dressing changes and incision-related cost, range of motion (ROM), incision-related complications and incision evaluation scores were recorded.

Results

Thirty-two patients were enrolled in this study and followed at two months after surgery. In the knees of tissue adhesive, the times of dressing change and patient scar assessment scores (PSAS) were significantly less than those standard skin closure (p=0.000; p=0.003). Although there were no significant differences of the delayed discharge, incision-related cost, ROM, incision-related complications and Vancouver scar score (VSS) between two groups, 65.6% (21/32) patients preferred the tissue adhesive and only 15.6% (5/32) patients preferred the standard incision closure.

Conclusion

Tissue adhesive could effectively reduce postoperative wound drainage and improve patients’ satisfaction rate with no difference in medical costs and ROM in TKA. The application of tissue adhesive and subcuticular sutures might be one safe and convenient method of skin closure in TKA.

Chinese Clinical Trial Registry

ChiCTR1900025730; Registered 6 September 2019.

Photodegradable Hydrogels for Cell Encapsulation and Tissue Adhesion

Hydrogels for wound management and tissue gluing applications have to adhere to tissues for a given time scale and then disappear, either by removal from the skin or by slow degradation for applications inside the body. Advanced wound management materials also envision the encapsulation of therapeutic drugs or cells to support the natural healing process. The design of hydrogels that can fulfill all of these properties with minimal chemical complexity, a stringent condition to favor transfer into a real medical device, is challenging. Herein, we present a hydrogel design with a moderate structural complexity that fulfills a number of relevant properties for wound dressing: it can form in situ and encapsulate cells, it can adhere to tissues, and it can be degraded on demand by light exposure under cytocompatible conditions. The hydrogels are based on starPEG macromers terminated with catechol groups as cross-linking units and contain intercalated photocleavable nitrobenzyl triazole groups. Hydrogels are formed under mild conditions (N-(2-hydroxyethyl)piperazine-N'-ethanesulfonic acid (HEPES) buffer with 9-18 mM sodium periodate as the oxidant) and are compatible with encapsulated cells. Upon light irradiation, the cleavage of the nitrobenzyl group mediates depolymerization, which enables the on-demand release of cells and debonding from tissues. The molecular design and obtained properties reported here are interesting for the development of advanced wound dressings and cell therapies and expand the range of functionality of current alternatives.

Perineal skin tear repair following vaginal birth; skin adhesive versus conventional suture - a randomised controlled trial

This was a prospective randomised controlled trial comparing the effects of first-degree perineal tear repair using adhesive glue versus conventional suturing in terms of pain score, wound complication and patient's satisfaction. One hundred and twenty one women were randomised. The skin adhesive group had a significantly lower pain score at rest as well as during sitting, walking and micturition during the first week of delivery compared to the suture group. The time taken to become pain free was significantly shorter in the tissue adhesive group (3.18 vs. 8.65 days, p < .001). Only two patients who had skin glue experienced wound gaping. No significant difference was observed in the level of satisfaction between the adhesive and suture groups. Tissue adhesive is better than subcuticular suture for repairing first-degree perineal tear as it causes less pain and has shorter recovery time.Impact statementWhat is already known on this subject. First- and second-degree tears following vaginal delivery are common and involved a third of women. Suturing of these tears is advocated to avoid wound gaping and poor healing.What the results of this study add. For first-degree tear repair, tissue adhesive is better than conventional suture in terms of pain reduction and recovery time.What the implications are of these findings for clinical practice and/or further research. Skin adhesive is an ideal method for first-degree perineal tear repair especially in out of hospital settings such as home birth or midwifery-led centre. A larger scale study is needed to establish its feasibility for second- and third-degree tears repair.

A simple modified surgical technique combined with tissue adhesive for steatocystoma multiplex

BACKGROUND

Steatocystoma multiplex (SM) is a disorder of the pilosebaceous unit characterized by multiple sebum-containing dermal cysts. Psychological distress of patients is always derived from these undesirable lesions. Although various treatments have been attempted to improve cosmetic outcomes, no optimal treatment strategy has been established to date..

AIMS

To provide a facile and practical surgical technique combined with tissue adhesive for the treatment of steatocystoma multiplex.

METHOD

Forty patients diagnosed as SM were treated with simple modified surgical technique. After local anesthesia, the surface skin was incised about 1-2 mm using a No. 11 blade. When the wall was punctured, the cyst should be squeezed to cause the contents to come out first. Then, we used single toothed forceps which were inserted through the narrow incision. When the cyst was exposed, the mosquito forceps grasp the portion of the cyst and pull it out gently. Then, the incisions were pressed locally, and tissue adhesive was employed to align them when there was no bleeding. We just took approximately 1-2 minutes to excise one cyst completely.

RESULT

We successfully treated forty SM patients with our simple modified surgical technique. After treatment, excellent clinical outcomes and minimal adverse effects were observed in this study. And more importantly, no recurrence was found 12 months after the surgery.

CONCLUSION

Our simple modified surgical technique was proved to be practical and have excellent results in the long run. We highly recommend this treatment technique as the first-line therapy for SM.

Functionalized Multiarmed Polycaprolactones as Biocompatible Tissue Adhesives

Existing tissue adhesives have a trade-off between adhesive strength and biocompatibility. Here, we report a series of biocompatible multiarmed polycaprolactones (PCL) as tissue adhesives that can be released from a hot glue gun and the length of each arm was kept at ∼2-3 kg mol^-1 in all the polymers. The adhesion properties were dependent on the number of functionalized (N-hydroxysuccinimide ester (NHS), aldehyde (CHO), and isocyanate (NCO)) arms of the multiarmed polymers. The more arms, the higher the adhesion strength. For example, the adhesion strength in binding cut rat skin increased from 2.3 N cm^-2 for 2PCL-NHS to 11.2 N cm^-2 for 8-PCL-NHS. CHO- and NCO-modified 8PCL also had suitable adhesive properties. All the multiarmed polymers had minimal cytotoxicity in vitro and good biocompatibility in vivo, suggesting their potential as promising alternative surgical adhesives.

Mussel-Inspired Injectable Hydrogel Adhesive Formed under Mild Conditions Features Near-Native Tissue Properties

Injectable hydrogel adhesives, especially those that can strongly adhere to tissues and feature near-native tissue mechanical properties, are desirable biomaterials for tissue repair. Compared to nonadhesive injectable hydrogels for minimally invasive delivery of therapeutic agents, they can better retain the delivered agents at targeted tissue locations and provide additional local physical barriers. However, regardless of recent advances, an ideal injectable hydrogel adhesive with both proper adhesion and mechanical matching between hydrogels and tissues is yet to be demonstrated with cytocompatible and efficient in situ curing methods. Inspired by marine mussels, where different mussel foot proteins (Mfps) function cooperatively to achieve excellent wet adhesion, we herein report a dual-mode-mimicking strategy by modifying gelatin (Gel) biopolymers with a single-type thiourea-catechol (TU-Cat) functionality to mimic two types of Mfps and their mode of action. This strategy features a minor, yet impactful modification of biopolymers, which gives access to collective properties of an ideal injectable hydrogel adhesive. Specifically, with TU-Cat functionalization of only ∼0.4-1.2 mol % of total amino acid residues, the Mfp-mimetic gelatin biopolymer (Gel-TU-Cat) can be injected and cured rapidly under mild and cytocompatible conditions, giving rise to tissue adhesive hydrogels with excellent matrix ductility, proper wet adhesion, and native tissue-like stress relaxation behaviors. Such a set of properties originating from our novel dual-mode-mimicking strategy makes the injectable hydrogel adhesive a promising platform for cell delivery and tissue repair.

Phosphoserine Functionalized Cements Preserve Metastable Phases, and Reprecipitate Octacalcium Phosphate, Hydroxyapatite, Dicalcium Phosphate, and Amorphous Calcium Phosphate, during Degradation, In Vitro

Phosphoserine modified cements (PMC) exhibit unique properties, including strong adhesion to tissues and biomaterials. While TTCP-PMCs remodel into bone in vivo, little is known regarding the bioactivity and physiochemical changes that occur during resorption. In the present study, changes in the mechanical strength and composition were evaluated for 28 days, for three formulations of αTCP based PMCs. PMCs were significantly stronger than unmodified cement (38-49 MPa vs. 10 MPa). Inclusion of wollastonite in PMCs appeared to accelerate the conversion to hydroxyapatite, coincident with slight decrease in strength. In non-wollastonite PMCs the initial compressive strength did not change after 28 days in PBS (p > 0.99). Dissolution/degradation of PMC was evaluated in acidic (pH 2.7, pH 4.0), and supersaturated fluids (simulated body fluid (SBF)). PMCs exhibited comparable mass loss (<15%) after 14 days, regardless of pH and ionic concentration. Electron microscopy, infrared spectroscopy, and X-ray analysis revealed that significant amounts of brushite, octacalcium phosphate, and hydroxyapatite reprecipitated, following dissolution in acidic conditions (pH 2.7), while amorphous calcium phosphate formed in SBF. In conclusion, PMC surfaces remodel into metastable precursors to hydroxyapatite, in both acidic and neutral environments. By tuning the composition of PMCs, durable strength in fluids, and rapid transformation can be obtained.

First Aldol Cross-Linked Hyaluronic Acid Hydrogel: Fast and Hydrolytically Stable Hydrogel with Tissue Adhesive Properties

Currently, there are limited approaches to tailor 3D scaffolds cross-linked with a stable covalent C-C bond that does not require any catalysts or initiators. We present here the first hydrogels employing aldol condensation chemistry that exhibit exceptional physicochemical properties. We investigated the aldol-cross-linking chemistry using two types of aldehyde-modified hyaluronic acid (HA) derivatives, namely, an enolizable HA-aldehyde (HA-Eal) and a non-enolizable HA-aldehyde (HA-Nal). Hydrogels formed using HA-Eal demonstrate inferior cross-linking efficiency (due to intramolecular loop formation), when compared with hydrogels formed by mixing HA-Eal and HA-NaI leading to a cross-aldol product. The change in mechanical properties as a result of cross-linking at different pH values is determined using rheological measurements and is interpreted in terms of molecular weight between cross-links (M_c). The novel HA cross-aldol hydrogel demonstrate excellent hydrolytic stability and favorable mechanical properties but allow hyaluronidase-mediated enzymatic degradation. Interestingly, residual aldehyde functionality within the aldol product rendered the tissue-adhesive properties by bonding two bone tissues. The aldehyde functionality also facilitated facile post-synthetic modifications with nucleophilic reagents. Finally, we demonstrate that the novel hydrogel is biocompatible with encapsulated stem cells that show a linear rate of expansion in our 3-6 days of study.

An Antimicrobial Dental Light Curable Bioadhesive Hydrogel for Treatment of Peri-Implant Diseases

Dental implants constitute the standard of care to replace the missing teeth, which has led to an increase in the number of patients affected by peri-implant diseases (PIDs). Here, we report the development of an antimicrobial bioadhesive, GelAMP, for the treatment of PIDs. The hydrogel is based on a visible light-activated naturally-derived polymer (gelatin) and an antimicrobial peptide (AMP). The optimized formulation of GelAMP could be rapidly crosslinked using commercial dental curing systems. When compared to commercial adhesives, the bioadhesives exhibited significantly higher adhesive strength to physiological tissues and titanium. Moreover, the bioadhesive showed high cytocompatibility and could efficiently promote cell proliferation and migration in vitro. GelAMP also showed remarkable antimicrobial activity against Porphyromonas gingivalis. Furthermore, it could support the growth of autologous bone after sealing calvarial bone defects in mice. Overall, GelAMP could be used as a platform for the development of more effective therapeutics against PIDs.