Cytotoxicity of polymerized commercial cyanoacrylate adhesive on cultured human oral fibroblasts

Dipeptide-Based Photoreactive Instant Glue for Environmental and Biomedical Applications

Nature-inspired smart materials offer numerous advantages over environmental friendliness and efficiency. Emulating the excellent adhesive properties of mussels foot proteins, where the lysine is in close proximity with the 3,4-dihydroxy-l-phenylalanine (DOPA), we report the synthesis of a novel photocurable peptide-based adhesive consisting exclusively of these two amino acids. Our adhesive is a highly concentrated aqueous solution of a monomer, a cross-linker, and a photoinitiator. Lap-shear adhesion measurements on plastic and glass surfaces and comparison with different types of commercial adhesives showed that the adhesive strength of our glue is comparable when applied in air and superior when used underwater. No toxicity of our adhesive was observed when the cytocompatibility on human dermal fibroblast cells was assessed. Preliminary experiments with various tissues and coral fragments showed that our adhesive could be applied to wound healing and coral reef restoration. Given the convenience of the facile synthesis, biocompatibility, ease of application underwater, and high adhesive strength, we expect that our adhesive may find application, but not limited, to the biomedical and environmental field.

Choosing a treatment method for post-catheterization pseudoaneurysms guided by the late to early velocity index

Ultrasound-guided thrombin injection (UGTI) is often the first-line treatment for iatrogenic post-catheterization pseudoaneurysms (psA). There are also first reports of the use of biologically derived tissue glues (TG) instead of sole thrombin especially when UGTI was unsuccessful or in case of psA recurrence. Previously, we have established that a late to early velocity index (LEVI) < 0.2 could be a predictor of an increased risk of psA recurrence after standard UGTI. In this paper, we report our first experiences when the choice of the first-line treatment method was based on LEVI assessment. From May 2017 till January 2020 we included 36 patients with psA. Of them, 10 had LEVI < 0.2 and they underwent ultrasound-guided tissue glue injection (UGTGI) with biological TG and 26 had LEVI > 0.2 and they underwent UGTI. The injection set containing human thrombin and fibrinogen was used for UGTGI. Bovine thrombin was used for UGTI. The success rate was 100% and no psA recurrence was detected during a 2-week follow-up. It was significantly better when compared to the expected recurrence rates based on our previous 14 years of experience (0% vs. 13%, p = 0.01). All complications (10% in the UGTGI group and 15% in the UGTI group) were mild and transient and included clinical symptoms of paresthesia, numbness, tingling, or pain. Their rates were comparable to the rates we previously reported. No significant differences in other characteristics were observed. The approach to choose the first-line treatment method for iatrogenic psA based on LEVI is encouraging. It may increase the success rate and avoid unnecessary repetition of the procedure, without increasing complication rate while keeping costs of the procedure reasonable.

Enhanced skin adhesive property of α-cyclodextrin/nonanyl group-modified poly(vinyl alcohol) inclusion complex film

For skin contact medical devices, realizing a strong contact with skin is essential to precisely detect human biological information and enable human-machine interaction. In this study, we aimed to fabricate and characterize an inclusion complex film (ICF) for skin adhesion using α-cyclodextrin (α-CD) and nonanyl group-modified PVA (C9-PVA) under wet conditions. Based on the water insolubility of C9-PVA and the inclusion ability of α-CD for alkyl groups, α-CD/C9-PVA ICF was prepared. Among the prepared ICFs, α-CD/2.5C9-PVA (w/w = 0.5) ICF showed the highest bonding strength and T-peeling strength to porcine skin. Furthermore, α-CD/2.5C9-PVA (w/w = 0.5) ICF had better water vapor transmission rate than that of commercial tapes. In addition, the ion permeability test revealed that α-CD/2.5C9-PVA (w/w = 0.5) ICF exhibited excellent Na and Cl ion permeability. These results demonstrated that the multi-functional α-CD/2.5C9-PVA (w/w = 0.5) ICF can be a promising adhesive for skin contact medical devices.

Short-chain cyanoacrylates and long-chain cyanoacrylates (Dermabond) have different antimicrobial effects

Objective

To compare the antimicrobial effect in vitro of a short-chain cyanoacrylate with a long-chain cyanoacrylate (Dermabond, Ethicon, Johnson and Johnson, USA) against bacterial strains.

Methods and analysis

The following bacterial strains were analysed: Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia and Pseudomonas aeruginosa. For each microorganism, standardised sterile discs (6 mm) containing 10 µL of ethyl-cyanoacrylate and 2-octyl cyanoacrylate were applied to the plate. All plates received a blank filter-paper disc with no adhesive (control). All plates were incubated for 24 hours, after which the bacterial inhibitory halos, if present, were measured in millimetres in its greater length.

Results

Inhibitory halos were observed for both adhesives for S. aureus. Inhibition halos were observed only for ethyl-cyanoacrylate for K. pneumoniae and E. coli. No inhibition halo was observed for P. aeruginosa in any sample. The relationship between the total size of the inhibition halos and the diameter of the paper filter for S. aureus was statistically significant compared with 2-octyl cyanoacrylate.

Conclusion

Data shown conclude that ethyl-cyanoacrylate showed in vitro bacteriostatic activity for S. aureus, E. coli and K. pneumoniae. 2-Octyl cyanoacrylate showed in vitro lower bacteriostatic activity only against S. aureus when compared with ethyl-cyanoacrylate. No in vitro bactericidal activity of ethyl-cyanoacrylate or 2-octyl cyanoacrylate was observed.

Enhanced skin adhesive property of electrospun α-cyclodextrin/nonanyl group-modified poly(vinyl alcohol) inclusion complex fiber sheet

Many medical tapes on the market lack sufficient adhesive strength and breathability. Owing to its high biocompatibility, poly(vinyl alcohol) (PVA), a synthetic polymer, has attracted attention in the medical field. In this study, we aimed to prepare an inclusion complex fiber (ICFiber) using α-cyclodextrin (α-CD) and nonanyl-group-modified PVA (C9-PVA) for skin adhesion with improved performance. By changing the concentration of α-CD, six microfiber sheets were fabricated by electrospinning the α-CD/2.3C9-PVA inclusion complex solutions. The bonding strength and energy of the ICFiber sheets on the porcine skin were evaluated. Among the tested ICFiber sheets, the ICFiber-3 (molar ratio of α-CD/C9 groups was 0.612) sheet showed high tensile strength and break strain. The bonding strength and energy of ICFiber-3 sheet on porcine skin were 1.10 ± 0.11 N and 5.07 ± 0.94 J m-2, respectively, in the presence of water. In addition, ICFiber-3 sheet showed a better water vapor transmission rate (0.95 ± 0.02 mL per day) than commercial tapes. These results demonstrate that the α-CD/2.3C9-PVA ICFiber sheet is a promising adhesive for wearable medical devices.

Biomaterials in Gastroenterology: A Critical Overview

In spite of the large diversity of diagnostic and interventional devices associated with gastrointestinal endoscopic procedures, there is little information on the impact of the biomaterials (metals, polymers) contained in these devices upon body tissues and, indirectly, upon the treatment outcomes. Other biomaterials for gastroenterology, such as adhesives and certain hemostatic agents, have been investigated to a greater extent, but the information is fragmentary. Much of this situation is due to the paucity of details disclosed by the manufacturers of the devices. Moreover, for most of the applications in the gastrointestinal (GI) tract, there are no studies available on the biocompatibility of the device materials when in intimate contact with mucosae and other components of the GI tract. We have summarized the current situation with a focus on aspects of biomaterials and biocompatibility related to the device materials and other agents, with an emphasis on the GI endoscopic procedures. Procedures and devices used for the control of bleeding, for polypectomy, in bariatrics, and for stenting are discussed, particularly dwelling upon the biomaterial-related features of each application. There are indications that research is progressing steadily in this field, and the establishment of the subdiscipline of "gastroenterologic biomaterials" is not merely a remote projection. Upon the completion of this article, the gastroenterologist should be able to understand the nature of biomaterials and to achieve a suitable and beneficial perception of their significance in gastroenterology. Likewise, the biomaterialist should become aware of the specific tasks that the biomaterials must fulfil when placed within the GI tract, and regard such applications as both a challenge and an incentive for progressing the research in this field.

Cyanacrylate Glue Caused Extrinsic Compression of an Infrapopliteal Vein Graft

Several surgical sealant devices are commercially available after their rigorous clinical testing with no apparent complications reported so far in the current literature. Cyanoacrylate glue can be used to stabilize the anastomoses and permit a better tensile strength in cardiovascular surgery. We first report the case of a 71-year-old male patient presenting with symptoms of progressive limitation of walking distance, 13 months after a successful femoroinfrapopliteal bypass surgery, because of a calcified tissue extrinsically stenosizing the first segment of the previous bypass graft, caused by the use of cyanoacrylate glue.

Evaluation of Regular Market Ethyl Cyanoacrylate Cytotoxicity for Human Gingival Fibroblasts and Osteoblasts

Background: The aim of this study was to evaluate the cytotoxicity of cyanoacrylate adhesives in an indirect contact assay in human gingival fibroblast (FGH) and oral osteoblasts (GO) lineages. Methods: Cover glasses were glued with adhesives following the ISO 10993-2012 protocol. The groups were: C (control with cells and regular Dulbecco Modified Eagle Medium; LC (liquid ethyl-cyanoacrylate); GC (ethyl-cyanoacrylate gel); EGC (easy gel [ethyl-cyanoacrylate]); and D (Dermabond [octyl-cyanoacrylate]). Each cell linage was plated in the sixth passage using 10⁴ cells. Cell viability was measured by the MTT test at 24, 48, 72, and 96 hours. Data were analyzed by two-way analysis of variance complemented by the Tukey test, with p < 0.05 being significant. Results: Dermabond stimulated osteoblast viability at 72 h (p < 0.05). All other groups were similar to the control cells (p > 0.05). For the fibroblasts, there was no difference in the groups, including the control except that EGC was cytotoxic for these cells (p < 0.05). Conclusions: Ethyl-cyanoacrylate gel and liquid forms available on the general chemical market were not cytotoxic for oral osteoblasts and fibroblasts in most cases. However, the easy gel form was cytotoxic for fibroblasts.

Biocompatible alkyl cyanoacrylates and their derivatives as bio-adhesives

Cyanoacrylate adhesives and their homologues have elicited interest over the past few decades owing to their applications in the biomedical sector, extending from tissue adhesives to scaffolds to implants to dental material and adhesives, because of their inherent biocompatibility and ability to polymerize solely with moisture, thanks to which they adhere to any substrate containing moisture such as the skin.

Effect of 2-octylcyanoacrylate on placenta derived mesenchymal stromal cells on extracellular matrix

PURPOSE

Determine the effect of 2-octylcyanoacrylate on placenta derived mesenchymal stromal cells (PMSCs) seeded onto extracellular matrix (ECM) in order to assess its biocompatibility as a potential adhesive for in-vivo fetal cell delivery.

METHODS

PMSCs isolated from chorionic villus tissue were seeded onto ECM. A MTS proliferation assay assessed cellular metabolic activity at various time points in PMSC-ECM with direct, indirect, and no glue contact. Conditioned media collected prior to and 24 hours after glue exposure was analyzed for secretion of human brain-derived neurotrophic factor, hepatocyte growth factor, and vascular endothelial growth factor.

RESULTS

Direct and indirect contact with 2-octylcyanoacrylate results in progressively decreased cellular metabolic activity over 24 hours compared to no glue controls. Cells with direct contact are less metabolically active than cells with indirect contact. 24 hours of glue exposure resulted in suppression of growth factor secretion that is near complete with direct contact.

DISCUSSION

Exposure to 2-octylcyanoacrylate results in decreased metabolic activity and decreased measurable secretion of growth factors by PMSCs seeded onto ECM. Thus, the application of 2-octylcyanoacrylate glue should be limited when working with cell-engineered scaffolds as its inhibitory effects on cell growth and secretory function can limit the therapeutic potential of cell-based interventions.

Treatment of the degenerated intervertebral disc; closure, repair and regeneration of the annulus fibrosus

Degeneration of the intervertebral disc (IVD) and disc herniation are two causes of low back pain. The aetiology of these disorders is unknown, but tissue weakening, which primarily occurs due to inherited genetic factors, ageing, nutritional compromise and loading history, is the basic factor causing disc degeneration. Symptomatic disc herniation mainly causes radicular pain. Current treatments of intervertebral disc degeneration and low back pain are based on alleviating the symptoms and comprise administration of painkillers or surgical methods such as spinal fusion. None of these methods is completely successful. Current research focuses on regeneration of the IVD and particularly on regeneration of the nucleus pulposus. Less attention has been directed to the repair or regeneration of the annulus fibrosus, although this is the key to successful nucleus pulposus, and therewith IVD, repair. This review focuses on the importance of restoring the function of the annulus fibrosus, as well as on the repair, replacement or regeneration of the annulus fibrosus in combination with restoration of the function of the nucleus pulposus, to treat low back pain.

Mechanical and cytotoxicity testing of acrylic bone cement embedded with microencapsulated 2-octyl cyanoacrylate

The water-reactive tissue adhesive 2-octyl cyanoacrylate (OCA) was microencapsulated in polyurethane shells and incorporated into Palacos R bone cement. The tensile and compressive properties of the composite material were investigated in accordance with commercial standards, and fracture toughness of the capsule-embedded bone cement was measured using the tapered double-cantilever beam geometry. Viability and proliferation of MG63 human osteosarcoma cells after culture with extracts from Palacos R bone cement, capsule-embedded Palacos R bone cement, and OCA were also analyzed. Incorporating up to 5 wt % capsules had little effect on the compressive and tensile properties of the composite, but greater than 5 wt % capsules reduced these values below commercial standards. Fracture toughness was increased by 13% through the incorporation of 3 wt % capsules and eventually decreased below the toughness of the capsule-free controls at capsule contents of 15 wt % and higher. The effect on cell proliferation and viability in response to extracts prepared from capsule-embedded and commercial bone cements were not significantly different from each other, whereas extracts from OCA were moderately toxic to cells. Overall, the addition of lower wt % of OCA-containing microcapsules to commercial bone cement was found to moderately increase static mechanical properties without increasing the toxicity of the material.

Local drug delivery by personalized, intraoperative custom-made implant coating

Local administration of drugs can enhance regeneration, prevent infection, or treat postsurgical pain. If used in conjunction with implants, coating strategies should allow the choice of a drug or combination of drugs, their doses, localization, and release due to intraoperative considerations. Current coating technologies lack the ability for personalized medicine strategies. Here, we describe a new intraoperative strategy for drug delivery that allows a personalized approach as local drug delivery by implant coating. A polyvinylalcohol (PVA) patch provides rapid attachment to implant surfaces by cyanoacrylate (CA) adhesives. The CA polymerization was initiated by water uptake of the patch due to exposure to a humid environment. The coating strength depended on the type of the CA, the time of external pressing load and humidification, the properties of the patch and the implant surface. The CA adhesive penetrated and polymerized within the patch without impeding the bioactivity of the embedded molecules or strongly altering the protein release pattern after attachment to the implant surface. The use of CA in combination with the PVA patch proved to be noncytotoxic in vitro. This technology platform opens the possibility for personalized medicine to locally administer drugs due to intraoperative requirements.

The photocrosslinkable tissue adhesive based on copolymeric dextran/HEMA

We developed a copolymeric bioadhesive system with the potential to be used as a tissue adhesive based on biopolymer dextran. Copolymeric hydrogels comprising a urethane dextran (Dex-U) and 2-hydroxyethyl methacrylate (HEMA) were prepared and crosslinked under the ultraviolet (UV) irradiation. In this study, the photopolymerization process was monitored by real time infrared spectroscopy (RTIR). The adhesion strength was evaluated by lap-shear-test. The surface tension, viscosity of the solutions and the cytotoxicity assays were investigated. Compared to Dex-U system, the addition of HEMA remarkably improved the properties of Dex-H system especially the adhesion strength and the nontoxicity. And materials variation could be tailored to match the need of tissues. The copolymeric tissue adhesives demonstrated promising adhesion strength and nontoxicity. The maximum adhesion strength reached to 4.33±0.47 Mpa which was 86 times higher than that of Tisseel. The obtained products have the potential to serve as tissue adhesive in the future.

In vitro and in vivo studies on the use of Histoacryl(®) as a soft tissue glue

The skin adhesive Histoacryl(®) consists of n-butyl-2-cyanoacrylate which polymerises in contact with moisture. It is not fully biodegradable, produces heat during polymerisation and releases products which are toxic and inhibit cell growth. Clinical application is exclusively approved to glue skin. However, there are also clinical studies and case reports in the scientific literature, which discuss the application of Histoacryl(®) as a soft tissue adhesive. In parallel to an analysis of the literature which discusses the usage of Histoacryl(®) in head and neck surgery, we performed in vitro and in vivo investigations with this adhesive. In vitro, the vitality of cultured cell lines which where treated with extracts of Histoacryl(®) was determined with a viability assay. In addition, Histoacryl(®) was examined by fixing defined mucous membrane of the nasal septum in an animal study in rabbits. The analysis of the literature shows both positive and negative results for the application of Histoacryl(®) as a soft tissue adhesive depending on the manner and place of the application as well as the applied amount of glue. Our own results confirm a negative influence of Histoacryl(®) on the viability of cultured cells and soft tissue. The histological examination showed that a better biocompatibility is achieved if the glue is used in small amounts. Both the literature study as well as the in vitro and in vivo examinations showed that the usage of Histoacryl(®) as a soft tissue glue may be arguable. Critical factors are the moisture at the application area and the applied amount of glue.

Elasticity and safety of alkoxyethyl cyanoacrylate tissue adhesives

Cyanoacrylate glues are easily applied to wounds with good cosmetic results. However, they tend to be brittle and can induce local tissue toxicity. A series of cyanoacrylate monomers with a flexible ether linkage and varying side-chain lengths was synthesized and characterized for potential use as tissue adhesives. The effect of side-chain length on synthesis yield, physical and mechanical properties, formaldehyde generation, cytotoxicity in vitro and biocompatibility in vivo were examined. The incorporation of etheric oxygen allowed the production of flexible monomers with good adhesive strength. Monomers with longer side-chains were found to have less toxicity both in vitro and in vivo. Polymerized hexoxyethyl cyanoacrylate was more elastic than its commercially available and widely used alkyl analog 2-octyl cyanoacrylate, without compromising biocompatibility.

Adesivos à base de cianoacrilato para síntese de tecido mole

FUNDAMENTOS - Adesivos teciduais têm sido muito usados para síntese de ferida, em função de ser um método indolor, rápido e de fácil execução. OBJETIVOS -Analisar e comparar compatibilidade dos adesivos, etil- cianoacrilato (Super Bonder) e butilcianoacrilato (Histoacryl), e a reparação de incisões em dorso de ratos entre o fio de sutura e os respectivos adesivos. MÉTODOS - Foram usados 15 ratos. Realizaram-se duas lojas cirúrgicas no dorso. Em cada uma, foi implantado um tubo de polietileno (10mm x 1mm), os quais foram preenchidos com os adesivos Super Bonder (lado direito) e Histoacryl (lado esquerdo). As incisões, do lado esquerdo, foram coaptadas com Super Bonder, e as do lado direito, com Histoacryl. Uma incisão mediana, entre as duas incisões,foi realizada e suturada com fio de seda. Os animais foram mortos, depois de 7(sete), 35(trinta) e 120 (cento e vinte dia) dias. RESULTADOS: Os adesivos usados, no presente estudo, não promoveram reação inflamatória, quando usados para síntese das incisões. Porém, estes adesivos, quando implantados no subcutâneo, promoveram reação inflamatória até 120 (cento e vinte dia) dias, no entanto, a reação é mais intensa com Histoacryl. CONCLUSÕES: Super Bonder e Histoacryl permitem o processo cicatricial dos tecidos incisados; facilitam a sutura das incisões. Desta forma, estes podem ser utilizados para sínteses de feridas, lacerações ou incisões cutâneas.

Acute lymphoblastic leukemia in a patient with chronic cyanoacrylate exposure

Environmental agents have long been thought to be linked to the development of malignancies. Due to the difficulty in identifying and verifying exposures to such agents, only a few chemical compounds are clearly linked to malignancies. We report here the case of a 36-year-old man with pre-B cell acute lymphoblastic leukemia. This patient was using industrial strength glue to reattach a chipped tooth for approximately 1 year, and such use was associated with chronic exposure of his oral mucosa to this glue. This case raises the possibility that chronic exposure to cyanoacrylates, the adhesive agents in industrial strength glue, may be associated with the development of acute lymphoblastic leukemia in humans.

SURGICAL APPLICATIONS OF CYANOACRYLATE ADHESIVES: A REVIEW OF TOXICITY

Cyanoacrylate (CA) and its homologues have a variety of medical and commercial applications as biological adhesives and sealants. Homologues of CA are being widely promoted in surgery as a tissue adhesive to replace traditional suturing techniques. Potential benefits of using CA adhesives include better cosmetic results, more rapid wound closure, and perhaps most significantly, the potential for significant reductions in percutaneous injuries from suture needles, which would in turn also reduce the risk of transmission of infectious diseases. Nevertheless, certain concerns have been raised regarding the potential toxicity of CA within patients, as well as among health professionals who are occupationally exposed when using CA compounds. Reported toxicity of CA in the workplace may result in dermatological, allergic and respiratory conditions. To help reduce the occupational burden, therefore, medical staff using CA adhesives should avoid direct contact with the compound and use appropriate personal protective measures at all times. Maintaining higher levels of humidity, optimizing room ventilation and using special air conditioning filters in surgical suites and operating theatres may also be useful in minimizing the exposure to volatile CA adhesives.

In vitro toxicity test of ethyl 2-cyanoacrylate, a tissue adhesive used in cardiovascular surgery, by fibroblast cell culture method

BACKGROUND

The aim of this study was to evaluate the cytotoxicity of cyanoacrylate polymers (ethyl 2-cyanoacrylate) by an elution test system. In such systems, the material is extracted with a cell culture medium, which is subsequently added onto cultured cells, resulting in an indirect contact between the biomaterial and cells.

METHODS

A cell line commonly utilized for cytotoxicity experiments; L929 mouse fibroblasts were used in this study. The effects of extract dilutions on cells were evaluated by two experiments: (a) The cells were suspended and seeded in a medium containing the extract, followed by a short incubation to observe the effects on cell attachment; (b) cells were seeded in a normal medium. Following cell attachment, this was replaced with a medium containing the extract and long-term effects on cell proliferation were measured. The cytotoxicity was quantified using a cell viability assay, well established for use in the evaluation of cell-biomaterial interactions.

RESULTS

These results indicate that, in the test system utilized, a tenfold dilution of the extract results in an approximately 10% decrease in cells; this increases to between 30% and 45% in a 1:1 dilution. When a large number of cells (3000/well) were used, proliferation of cells overcame the cytotoxic effect and consistent results could not be observed.

CONCLUSIONS

In this study, the observed outcomes follow a similar trend on cell attachment and proliferation with acute effects (4 hours incubation) of the extracts on the cells, producing slightly higher toxicity. Our findings are parallel with the literature findings.

Accidental cyanoacrylate glue ingestion

Cyanoacrylates have a variety of medical and commercial applications as adhesives. They are commonly found as glue in the household. They can be swallowed accidentally by children. However, no case was reported so far in the English medical literature. Their effect on the mouth, pharynx, larynx, esophagus and the rest of gastrointestinal system is unknown. Here we report our own child who accidentally ingested cyanoacrylate glue without unwanted sequelae due to prompt intervention.

Cellular, histomorphologic, and clinical characteristics of a new octyl-2-cyanoacrylate skin adhesive

Short-chained cyanoacrylates have been used for many years for topical skin closure. Toxic effects in cell culture of a new long-chained octyl-2-cyanoacrylate tissue adhesive are compared with those of short-chained ethyl-2- and butyl-2-cyanoacrylates. Two cellular tests were used: the agar overlay test and the MTT test. An in vitro test using copper plates coated with the three types of cyanoacrylates serves for evaluating the stability of polymerized skin adhesives. Bilateral neck skin incisions in Goettingen miniature pigs were glued on one side with Dermabond. On the other side, conventional sutures were applied. After the pigs were killed, the resulting skin samples were tested for the tensile strength of their wound stability. Samples of pig dermis were exemplarily and histomorphologically characterized. A clinical examination after submandibular lymph node dissection should examine the application in humans. Cell culture tests were used to show the toxic effects of the three cyanoacrylates. In a copper test, octyl-2-cyanoacrylate was more stabile than ethyl- and butyl-cyanoacrylates. Breaking strength was 30% lower 28 days after operation with the new product than with sutures. In electron microscopy, octyl-2-cyanoacrylate showed no disadvantages with regard to tissue regeneration and no histotoxicity. For plastic surgery, this new topical skin adhesive is a real alternative with attractive results, as compared with conventional suture.

Investigating the effects of bone cement, cyanoacrylate glue and marine mussel adhesive protein from Mytilus edulis on human osteoblasts and fibroblasts in vitro

Bone cement is a widely used standard fixation substance in Orthopaedic Surgery. Cyanoacrylate glue is available for wound closure to supplement suturing. The mussel adhesive protein extracted from Mytilus edulis (Cell-Tak, BD Biosciences, Heidelberg, Germany) is an experimental fixation device used for in vitro purposes of cell adhesion. The aim of this study is to introduce a cell culture model investigating the effects of commonly applied and experimental glues on human fibroblasts and osteoblasts in vitro. Cells cultured without additives served as a control group. Microscopic examination was performed to evaluate the morphologic changes. An apoptosis test (Apo-Tag, Chemicon International, Temecula, CA, U. S. A.) was applied to determine the rate of natural cell death at the end of the study. It could be demonstrated that morphological changes in bone cement are different in fibroblasts and osteoblasts. Osteoblasts seem to grow on bone cement and develop an orderly formation. Fibroblasts grow in a confluent monolayer around bone cement but do not adhere to the cement itself. This is a desirable effect since most Orthopaedic applications aim at osteointegration as opposed to fibrous tissue overgrowth. Apoptosis attributed to bone cement is comparable to the respective natural rate of apoptosis. Cyanoacrylate glue and the mussel adhesive protein lead to an almost complete apoptosis in the investigated cells. Their routine application should be avoided. The developed cell culture model seems appropriate for performing further investigations.

Tailoring lactide/caprolactone co-oligomers as tissue adhesives

This article introduces novel biocompatible tissue adhesives that do not involve any chemical or biochemical reactions, during their application in vivo. The use of these new adhesives is based exclusively on their temperature-dependent rheological properties. Since biocompatibility and biodegradability are additional crucial attributes of tissue adhesives, the polymers were tailored so that they as well as their degradation products are non-toxic. Branched oligomers consisting of a core molecule and biodegradable chains bound to it were synthesized and the relationship between their composition and their adhesive properties under in vitro conditions, was investigated. The oligomers comprised trimethylolpropane as the trifunctional central molecule, while lactoyl and caprolactone units formed the biodegradable segments. Oligomers with glass transition temperatures in the 20-25 degrees C range, were found to perform better. A strong connection was found between the length of the PLA blocks, the glass transition temperature (T(g)) of the different materials and their Adhesive Failure Strength (AFS) at 37 degrees C. The remarkable flexibilizing effect of the caprolactone units incorporated along the PLA blocks, allowed to generate longer biodegradable chains and to improve, therefore, the adhesive strength of the oligomers, while keeping their T(g) within the appropriate temperature interval. The TMP(LA(16)-CL(2)-LA(16)-CL(2)-LA(16))(3) oligomer attained especially high AFS values under in vitro conditions.