Microporous Mesh Research Articles

USE OF BIOLOGIC GLUE IN TAPP. TRICKS AND CHALLENGES

Abstract Aim The fixation of the mesh in transabdominal preperitoneal inguinal hernia repair (TAPP) and the closing of the peritoneal flap are key parts of the operation. This is accomplished with sutures or tackers. The use of biologic glue is an acceptable alternative with the possible advantages of being safer and less painful than the other options. Its use however poses its own set of challenges. Materials and Methods 24 patients underwent TAPP repair for inguinal hernia, using biologic glue to fix the mesh and close the peritoneal flap. The practical challenges of its use were studied. Results No problems were encountered in the fixation of the mesh. In the closing of the peritoneal flap, tackers were used as an adjunct in the first 10 cases. After that, the operation was completed only using glue. Conclusions Various conclusions were drawn from the use of glue. First, it works best in a dry environment and with a lightweight microporous mesh, so that the glue can seep through the pores. Second it will not “fix” large creases of the mesh, although this also means a suboptimal positioning of the mesh. Third, it requires gentle moves during withdrawal, as the tip can stick to the tissues, and appliance of a wet gauze after every use, as the clotted glue can block the tip. All in all, after a learning curve period, it can be a safe and effective alternative to sutures and tackers in TAPP.

Fabrication of Photo-Responsive Mesh Membrane with Surface-Engineered Wettability for Oil-Water Separation and Photocatalytic Degradation of Organic Pollutants.

A photo-responsive TiO2-coated stainless-steel mesh membrane (TiO2@SSM), possessing unique surface wettability, was fabricated. This TiO2@SSM membrane is found to be capable of separating oil and water from oily water and has the potential to carry out photocatalytic self-cleaning and/or the degradation of organic pollutants present in water. The fabrication of TiO2@SSM is quite simple: titanium dioxide (TiO2) nanoparticles were spray-coated onto stainless steel microporous mesh (SSM) substrates and annealed at the temperature of 500 °C. The fabricated TiO2@SSM membrane was structurally and morphologically characterized by XRD, FE-SEM, EDX, and elemental mapping. The contact angle measurements using a goniometer showed that the fabricated TiO2@SSM membrane surface is superhydrophilic and superoleophilic in air and superoleophobic under water. This is a favorable wetting condition for the water passing oil-water separation membrane, and this water passing property of the membrane eased the common problem of the fast clogging of the membrane by oil. An oil-water separation efficiency of about 99% was achieved, when the TiO2@SSM membrane was used as the separating medium in the gravity-driven oil-water separation system, unlike the uncoated stainless steel mesh membrane, which allowed both oil and water to pass together. This confirmed that the oil-water separating functionality of the membrane is attributed to TiO2 coating on the stainless steel mesh. The photocatalytic degradation property of the TiO2@SSM membrane is an added advantage, where the membrane can be potentially used for self-cleaning of the membrane's surface and/or for water purification.

Biomimetic Transparent Nanoplasmonic Meshes by Reverse-Nanoimprinting for Bio-Interfaced Spatiotemporal Multimodal SERS Bioanalysis.

Multicellular systems, such as microbial biofilms and cancerous tumors, feature complex biological activities coordinated by cellular interactions mediated via different signaling and regulatory pathways, which are intrinsically heterogeneous, dynamic, and adaptive. However, due to their invasiveness or their inability to interface with native cellular networks, standard bioanalysis methods do not allow in situ spatiotemporal biochemical monitoring of multicellular systems to capture holistic spatiotemporal pictures of systems-level biology. Here, a high-throughput reverse nanoimprint lithography approach is reported to create biomimetic transparent nanoplasmonic microporous mesh (BTNMM) devices with ultrathin flexible microporous structures for spatiotemporal multimodal surface-enhanced Raman spectroscopy (SERS) measurements at the bio-interface. It is demonstrated that BTNMMs, supporting uniform and ultrasensitive SERS hotspots, can simultaneously enable spatiotemporal multimodal SERS measurements for targeted pH sensing and non-targeted molecular detection to resolve the diffusion dynamics for pH, adenine, and Rhodamine 6G molecules in agarose gel. Moreover, it is demonstrated that BTNMMs can act as multifunctional bio-interfaced SERS sensors to conduct in situ spatiotemporal pH mapping and molecular profiling of Escherichia coli biofilms. It is envisioned that the ultrasensitive multimodal SERS capability, transport permeability, and biomechanical compatibility of the BTNMMs can open exciting avenues for bio-interfaced multifunctional sensing applications both in vitro and in vivo.

Microporous Multiresonant Plasmonic Meshes by Hierarchical Micro-Nanoimprinting for Bio-Interfaced SERS Imaging and Nonlinear Nano-Optics.

Microporous mesh plasmonic devices have the potential to combine the biocompatibility of microporous polymeric meshes with the capabilities of plasmonic nanostructures to enhance nanoscale light-matter interactions for bio-interfaced optical sensing and actuation. However, scalable integration of dense and uniformly structured plasmonic hotspot arrays with microporous polymeric meshes remains challenging due to the processing incompatibility of conventional nanofabrication methods with flexible microporous substrates. Here, scalable nanofabrication of microporous multiresonant plasmonic meshes (MMPMs) is achieved via a hierarchical micro-/nanoimprint lithography approach using dissolvable polymeric templates. It is demonstrated that MMPMs can serve as broadband nonlinear nanoplasmonic devices to generate second-harmonic generation, third-harmonic generation, and upconversion photoluminescence signals with multiresonant plasmonic enhancement under fs pulse excitation. Moreover, MMPMs are employed and explored as bio-interfaced surface-enhanced Raman spectroscopy mesh sensors to enable in situ spatiotemporal molecular profiling of bacterial biofilm activity. Microporous mesh plasmonic devices open exciting avenues for bio-interfaced optical sensing and actuation applications, such as inflammation-free epidermal sensors in conformal contact with skin, combined tissue-engineering and biosensing scaffolds for in vitro 3D cell culture models, and minimally invasive implantable probes for long-term disease diagnostics and therapeutics.

EP.TU.734Rectal mesh erosion post pelvic gynaecological surgery: A literature review

Abstract Introduction Surgical mesh has long been used for the repair of pelvic organ prolapse. In recent years high rates of serious complications have been reported and the US has withdrawn it from use, while the UK advises extreme caution. Here, we present a review of the literature with a focus on causative factors. Methods Twenty-three articles were included in the review: 21 cases of rectal mesh erosion and three cases of sigmoid mesh erosion. Causative factors were subdivided into patient-related, mesh-related and procedure-related. Results Main patient related risk factors included pre-existing intestinal diseases (reported in 4 cases) and an older age (median 65.5). Risk factors that were mesh related included increased porosity. 11 cases were reported with a macroporous (>75µm) mesh, whereas only 1 case had used a microporous (<10µM) mesh. 9 cases with partial/ no details of the mesh. The main risk factor that was procedure related was concomitant hysterectomy with 7 cases of mesh erosion had concomitant hysterectomy, 11 cases without concomitant hysterectomy, with a further 5 being unclear. Conclusion Pre-existing bowel disease, mesh type and mechanical factors associated with surgical technique all influenced the risk of mesh erosion into the bowels. A lack of reported information regarding the original surgical mesh and operation hindered the ability to draw conclusions. A step into rectifying this in the future would be the provision of medical device cards directly to the patient detailing the mesh.

Preparation of Cellulose/Chitin Blend Materials and Influence of Their Properties on Sorption of Heavy Metals

A series of biodegradable cellulose/chitin materials (beads and membranes) were successfully prepared by mixing cellulose with chitin in an NaOH/thiourea–water system and coagulation in a H2SO4 solution. The effects of chitin content on the materials’ mechanical properties, morphology, structure, and sorption ability for heavy metal ions (Pb2+, Cd2+, and Cu2+) were studied by tensile tests, scanning electron micrographs, Fourier transform infrared spectroscopy, and atomic absorption spectrophotometry. The results revealed that the cellulose/chitin blends exhibited relatively good mechanical properties, a homogeneous, microporous mesh structure, and the existence of strong hydrogen bonds between molecules of cellulose and chitin when the chitin content was less than 30 wt%, which indicated a good compatibility of the cellulose/chitin materials. Furthermore, in the same chitin content range, Pb2+, Cd2+, and Cu2+ can be adsorbed efficiently onto the cellulose/chitin beads at pH0 = 5, and the sorption capacity of the beads is more than that of chitin flakes. This shows that the hydrophilicity and microporous mesh structure of the blends are favorable for the kinetics of sorption. Preparation of environmentally friendly cellulose/chitin blend materials provides a simple and economical way to remove and recover heavy metals, showing a potential application of chitin as a functional material.

BETWEEN PROLENE®, ULTRAPRO® AND BARD SOFT® MESHES WHICH PRESENTS THE BEST PERFORMANCE IN THE REPAIR OF THE ABDOMINAL WALL?

In the definition of the mesh to be used to correct hernias, porosity, amount of absorbable material and polypropylene should be considered in the different stages of healing process. To evaluate the inflammatory reaction in the use of macro and microporous meshes of high and low weight in the repair of defects in the abdominal wall of rats. Ninety Wistar rats (Rattus norvegicus albinus) were used. The animals were submitted to similar surgical procedures, with lesion of the ventral abdominal wall, maintaining the integrity of the parietal peritoneum and correction using the studied meshes (Prolene®, Ultrapro® and Bard Soft®). Euthanasia was performed at 30, 60 and 120 days after surgery. The abdominal wall segments were submitted to histological analysis using H&E, Masson's trichrome, immunohistochemistry, picrosirius red and tensiometric evaluation. On the 120th day, the tensiometric analysis was superior with Ultrapro® macroporous mesh. The inflammatory process score showed a significant prevalence of subacute process at the beginning and at the end of the study. Microporous meshes showed block encapsulation and in macroporous predominance of filamentous encapsulation. The Ultrapro® mesh showed better performance than the others in healing process of the abdominal wall.

Proof of concept, design, and manufacture via 3‐D printing of a mesh with bactericidal capacity: Behaviour in vitro and in vivo

Currently, hernia treatment involves implantation of a mesh prosthesis, usually made of polypropylene, and the primary complication is infection of the device, which leads to an exponential increase in morbidity. Three-dimensional printing offers a method of dealing with complications of this magnitude. Therefore, in this study, the bactericidal properties and effectiveness of three-dimensional-printed meshes with polycaprolactone (PCL) and gentamicin were evaluated in vitro in Escherichia coli cultures, and their histological behaviour was examined in vivo. Different PCL meshes were implanted into four groups of rats, with 10 rats in each group: PCL meshes, PCL meshes with alginate and calcium chloride, PCL meshes with gentamicin, and PCL meshes with alginate and gentamicin. Thirty-six microporous meshes were manufactured, and their bactericidal properties were assessed. When the meshes did not include an antibiotic, an inhibition halo was not observed; when the gentamicin was free, an asymmetric inhibition area of 5.65 ± 0.46 cm2 was present; when the gentamicin was encapsulated, a rectangular area of 5.40 ± 0.38 cm2 was observed. In the rats, macroporous and microporous mesh implants produced mild inflammation and substantial fibrosis with collagen and neovascular foci. A significant difference was observed in fibroblastic activity between the PCL with alginate group and the PCL with alginate and gentamicin group microporous meshes (p = .013) and in collagen deposits between the macroporous and microporous meshes in the PCL mesh group (p = .033). The feasibility of manufacturing drug-doped printed PCL meshes containing alginate and gentamicin was verified, and the meshes exhibited bactericidal effects and good histopathological behaviour.

Fabrication and Characterization of Medical Mesh-Nebulizer for Aerosol Drug Delivery

In the field of drug delivery, a nebulizer is a device used to convert liquid drugs into tiny airborne droplets, such as aerosol or a mist form. These fine droplets are delivered to a patient’s lungs and airways and then spread throughout the body via blood vessels. Therefore, nebulization therapy is a highly-effective method compared with existing drug delivery methods. To enhance the curative influence of a drug, this study suggests the use of a new micro-porous mesh nebulizer consisting of a controllable palladium–nickel (Pd–Ni) membrane filter, piezoelectric element, and a cavity in the micro-pump. In this research, we optimize a biocompatible Pd–Ni membrane filter, such that it generated the smallest aerosol particles of various drugs. The pore size of the filter outlet is 4.2 μm ± 0.15 μm and the thickness of the Pd-Ni membrane filter is approximately 41.5 μm. In addition, the Pd–Ni membrane filter has good biocompatibility with normal cells. The result of a spray test with deionized (DI) water indicated that the size of a standard liquid droplet is 4.53 μm. The device has an electrical requirement, with a low power consumption of 2.5 W, and an optimal operation frequency of 98.5 kHz.

Graphene Oxide-Based Biocompatible 3D Mesh with a Tunable Porosity and Tensility for Cell Culture.

One of the major challenges associated with modeling the influence of the cellular microenvironment on cell growth and differentiation is finding suitable substrates for growing the cells in a manner that recapitulates the cell-cell and cell-microenvironmental interactions in vitro. As one approach to address this challenge, we have developed graphene oxide (GO)-3D mesh with tunable hardness and porosity for application in cell culture systems. The synthetic method of GO-3D mesh is simple, easily reproducible, and low cost. The foundation of the method is the combination of poly(ethylene)(glycol) (PEG) and GO together with a salt-leaching approach (NaCl) in addition to a controlled application of heat during the synthetic process to tailor the mechanical properties, porosity, and pore-size distribution of the resulting GO-3D mesh. With this methodology, the hydrogel formed by PEG and GO generates a microporous mesh in the presence of the NaCl, leading to the formation of a stable 3D scaffold after extensive heating and washing. Varying the ratio of NaCl to GO controls porosity, pore size, and pore connectivity for the GO-3D mesh. When the porosity is less than 90%, with an increasing ratio of NaCl to GO, the number of pores increases with good interconnectivity. The 3D-mesh showed excellent biocompatibility with vascular cells which can take on a morphology comparable to that observed in vessels in vivo. Cell proliferation and gene expression can be determined from cells grown on the GO-3D scaffold, providing a valuable tool for investigating cell-microenvironmental changes. The GO-3D mesh described results from the synergy of the combined chemical properties of the PEG and GO with the salt-leaching methodology to generate a unique and flexible mesh that can be modified and optimized for a variety of in vitro applications.

Ibuprofen-loaded PCL meshes manufactured using rapid tooling for ocular orbital repair

This study investigated the manufacture of resorbable polycaprolactone/ibuprofen (PCL/IBP) meshes by injection molding for application in ocular orbital repair. The pore dimension sizes used demonstrate that micro-porous meshes can be manufactured by injection molding using a prototype mold. The mechanical properties were observed to be dependent on the material composition and morphology. Lower stiffness, strength and elongation at failure were observed for the 8 mm pore sized samples. The PCL/Ibuprofen meshes initially showed a fast drug release but after 3 days the release was slow and controlled. The cytotoxicity test results of the PCL/Ibuprofen meshes indicated that the large initial quantity of Ibuprofen released was too high and resulted in cell toxicity. However, after this initial release, the PCL/Ibuprofen meshes showed a good interaction with the cells seeded on their surface. The presence of a low concentration of Ibuprofen does not negatively influence cell viability in culture.

Micro-computed tomography analysis of early stage bone healing using micro-porous titanium mesh for guided bone regeneration: preliminary experiment in a canine model.

The aim of this study was to evaluate the amount of bone formation beneath a defect area after treatment with titanium mesh membranes with different thicknesses and pore sizes alone or in combination with bone graft to induce bone formation during the early stage of healing time. The mandibular premolars were extracted bilaterally from three adult beagle dogs, and 8-mm-diameter bone defects were created on the buccal site of the premolar regions. Hydroxyapatite bone graft substitute was applied in the defect site unilaterally, and other site was left empty. Then, a novel micro-porous mesh (50μm in pore diameter) or commercially available macro-porous titanium mesh (1700μm in pore diameter) was placed on the defect and secured with screws. After 4weeks, the mandibles were harvested, imaged using micro-computed tomography, and prepared for histological and morphometric evaluation. Higher new bone volumes (mm3), percentage of new bone volumes in the total defect volumes (bone ratio: %), and new bone area (mm2) through morphometric evaluation were found on the novel membranes with 50-μm-diameter pores compared to the commercial titanium mesh. Moreover, experiment sites without bone graft were observed with higher new bone volume and bone ratio compared with sites with bone graft. However, bone mineral density of novel mesh was observed to be lower compared with other experimental sites. Under the experimental condition, the result of this study suggests that titanium meshes with 50-μm-diameter pores were effective for guided bone regeneration in the early stage of healing.

Large-Scale mRNA Transfection of Dendritic Cells by Electroporation in Continuous Flow Systems.

Electroporation is well established for transient mRNA transfection of many mammalian cells, including immune cells such as dendritic cells used in cancer immunotherapy. Therapeutic application requires methods to efficiently electroporate and transfect millions of immune cells in a fast process with high cell survival. Continuous flow of suspended dendritic cells through a channel incorporating spatially separated microporous meshes with a synchronized electrical pulsing sequence can yield dendritic cell transfection rates of >75% with survival rates of >90%. This chapter describes the instrumentation and methods needed for the efficient transfection by electroporation of millions of dendritic cells in one continuous flow process.

The influence of mesh topology in the abdominal wall repair process.

The tissue integration and the formation of adhesions in the repair of abdominal wall defects are principally led to the topology and the mechanical properties of implanted prosthesis. In this study we analyzed the influence of the topology of the meshes for abdominal wall repair, made of polypropylene (PP), evaluating its ability to prevent and to minimize the formation of adhesions, and to promote tissue ingrowth. Two series of in vivo studies were performed. In the first, two types of PP meshes, a lightweight macroporous mesh (LWM) and a heavyweight microporous mesh (HWM) were compared with determine the optimal porosity for tissue integration. In the second, a composite mesh, Clear Mesh Composite (CMC), made of a LWM sewn on a PP planar smooth film, was compared with a PP planar film, to demonstrate how two different topologies of same material are able to induce different tissue integration with the abdominal wall and different adhesion with internal organs. In both studies, the prostheses were implanted in Wistar rats and histological analysis and mechanical characterization of tissue coupled with the implants were performed. LWM showed better host tissue ingrowth in comparison to HWM. CMC prosthesis showed no adhesions to the viscera and no strong foreign body reaction, moreover its elasticity and anisotropy index were more similar to that of natural tissue. These results demonstrated that the surface morphology of PP surgical meshes allowed to modulate their repair ability. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1220-1228, 2016.

Vaginal mesh grafts and the Food and Drug Administration

Vaginal mesh grafts and the Food and Drug Administration

Evolution of Ordered Block Copolymer Serpentines into a Macroscopic, Hierarchically Ordered Web

Polymer coffee rings: Evaporation of diblock copolymer solutions confined in a sphere-on-flat geometry yields concentric serpentine microstructures over large areas (see picture, left). Selective solvent vapor annealing then transforms these microstructures into a macroscopic pattern of regularly arranged microporous mesh arrays (see picture, right) while at the same time forming domains of nanoscopic cylinders of diblock copolymer.

Barrier Membranes Used for Ridge Augmentation: Is There an Optimal Pore Size?

To identify the optimal pore size of barrier membranes for successful alveolar ridge reconstruction procedures, to determine if cortical perforations have any effect on bone regeneration, and to reiterate that bone graft containment is an important parameter for successful regeneration. This was a prospective, randomized, controlled study performed on hound dogs. Corticocancellous tibial bone grafting was performed to the lateral border of the mandible and protected with barrier membranes (meshes). The experiment analyzed three different pore sized meshes, compared with controls without the mesh. Two meshes (macroporous and microporous) were made of titanium, and one was a resorbable mesh. Meshes were preformed into the shape of a cube with one face open. Each side of the cube measured approximately 10 mm. Cubes were open-faced on one side, to facilitate packing of the graft material. The dogs received bilateral ramus grafts. Cortical perforations were created on the left ramus of all the dogs and compared with the right side, which did not have perforations. The dogs were randomly divided into 3 groups and sacrificed at intervals of 1, 2, and 4 months. Before sacrifice, all dogs received 2 doses of tetracycline as a marker for new bone formation. Histomorphometry was performed by using Bioquant image-analysis software. Areas of new bone and soft tissue were measured. The rate of mineral apposition was also calculated. All values obtained via histomorphometry were statistically analyzed with a t test. Thirty-one experimental sites were evaluated. The amount of new bone growth into the macroporous mesh was significantly higher than in the other groups. The mean area of new bone formation in large and small meshes was 66.26 +/- 13.78 mm(2) and 52.82 +/- 24.75 mm(2), respectively. In the resorbable mesh group, the mean area of new bone formed was 46.76 +/- 21.22 mm(2). The amount of new bone formed in the control group was 29.80 +/- 9.35 mm(2). There was no significant difference in amount of bone formation between left and right sides (P = .3172). Resorbable meshes had significant soft tissue ingrowth (23.47 mm(2)) compared with macroporous mesh (16.96 mm(2)) and microporous mesh (22.29 mm(2)). Controls had the least amount of soft tissue ingrowth (9.41 mm(2)). Mineral apposition rate was found to be higher in the resorbable group (2.41 microm/day), and the rate was lowest (1.09 microm/day) in the large pore mesh group. Macroporous membranes facilitated greater bone regeneration compared with microporous and resorbable membranes. Macroporous mesh also prevented significant soft tissue ingrowth compared with other meshes. Containment of a bone graft is the most critical parameter in successful bone regeneration. Cortical perforations did not have any effect on the quantity of regenerated bone. Further research should be directed toward identifying a critical pore size and manufacturing a reliable mesh that would prevent excessive soft tissue ingrowth in ridge augmentation procedures.

IN VITRO COMPARISON OF THREE DIFFERENT MESH CONSTRUCTIONS

Material amount and pore size have been recently discussed as probable important determinants of biocompatibility of mesh implants used in hernia repair. This study aimed to find out whether other constructional parameters affect the extent of early foreign body reaction in vitro. An NRK-49F (mixed culture of normal rat kidney cells) fibroblast culture was incubated in the presence of a 'light' microporous mesh (35 g/m(2), 0.25 mm thick), a 'heavy' polypropylene knitted mesh (95 g/m(2), 0.55 mm thick) and a polypropylene/polyglactin composite mesh (35 g/m(2), 0.5 mm thick). A mesh-free cell suspension was used as a control group. Fibroblasts' proliferation, invasion and apoptosis rates were measured by commercially available quantification tests. Levels of tumour necrosis factor-alpha, transforming growth factor-beta1, interleukin (IL)-1 beta, IL-6 and IL-10 secreted by the fibroblasts in the supernatant were dynamically measured in a time kinetics of 6-96 h. Invasion potential as well as proliferation and apoptosis rates of fibroblasts were enhanced by all meshes. The composite mesh stimulated the cell turnover with correspondingly increased levels of IL-6 and suppressed levels of transforming growth factor-beta1 significantly more than the two pure polypropylene meshes and the control group. Early biological response of fibroblasts as a major component of foreign body reaction was most affected by the filament construction of the mesh combining polypropylene with multifilament, partially absorbable polyglactin fibres. Material reduction did not weaken foreign body reaction. Confirming previous findings from animal experiments and clinical observations, the described in vitro model seems to be an appropriate primary tool for studying the biological tolerance towards meshes.