Silicone Particles Research Articles

Injectable polydimethylsiloxane microfiller coated with zwitterionic polymer for enhanced biocompatibility

Silicone-based fillers have been applied in several branches of medicine, such as soft tissue augmentation, because of their stability and durability. However, the inherently hydrophobic surfaces of silicone occasionally cause excessive deposition of the fibrous matrix in vivo, leading to severe fibrosis. In this study, we evaluated the use of a zwitterionic copolymer to offer a facile surface treatment method for silicone-based fillers and performed a preclinical trial of the formulation as-prepared. The copolymer has amphiphilic moieties, which act as macromolecular surfactants that can functionalize and stabilize the silicone particles during fabrication. The effectiveness and safety of the particle filler were evaluated histologically by scoring the peri-implant tissues into previously defined categories. Our results suggest that zwitterion-coated silicone fillers can inhibit protein adsorption, and thus, help attenuate foreign body reactions in a rat model. This demonstrates their potential for wide application in different fields within the discipline of medicine.

Assessment of Silicone Particle Migration Among Women Undergoing Removal or Revision of Silicone Breast Implants in the Netherlands

Silicone breast implants have been on the market for breast augmentation or breast reconstruction for approximately 60 years but may lead to medical complications, also called breast implant illness. To evaluate the existence of silicone gel bleed and migration over a long time period, including the period in which the newer cohesive silicone gel breast implants were used. In this single-center case series, capsule tissue and lymph node samples were collected from women who underwent removal or revision of silicone breast implants from January 1, 1986, to August 18, 2020, and data were extracted from the pathological reports and revision of the histology if data were missing. All tissues were examined using standard light microscopy, some extended with modified oil red O staining and energy-dispersive radiographic spectroscopy. A total of 365 women had capsular tissue removed, including 15 patients who also had lymph nodes removed, and 24 women had only lymph nodes removed. Data were analyzed from January to May 2021. Silicone breast implants. The main outcome was presence or absence of silicones inside or outside the capsule. One-way analysis of variance was used to determine significance between groups. Among a total of 389 women with silicone breast implants (mean [SD] age, 50.5 [11.2] years), 384 women (98.8%) had silicone particles present in the tissues, indicating silicone gel bleed. In 337 women (86.6%), silicone particles were observed outside the capsule (ie, in tissues surrounding the capsule and/or lymph nodes), indicating silicone migration. In 47 women (12.1%), silicone particles were only present within the capsule. In 5 women (1.2%), no silicone particles were detected in the tissues. Patients were divided into 2 groups, with 46 women who received cohesive silicone gel breast implants and 343 women who received either an older or a newer type of breast implant. There were no differences in silicone gel bleed or migration between groups (silicone detected outside or inside capsule: 44 women [95.7%] vs 340 women [99.1%]; P = .19). In this case series including women with noncohesive or cohesive silicone gel breast implants, silicone leakage occurred in 98.8% of women, indicating silicone gel bleed, and in 86.6% of women, migration of silicone particles outside the capsule was detected.

The Breast Tumor Microenvironment: Could Silicone Breast Implant Elicit Breast Carcinoma?

Complications related to breast implants have received much attention recently. Breast implant-associated anaplastic large cell lymphoma, silicone-induced granuloma of breast implant capsule, and breast implant illness are the main complications reported in the medical literature. However, the literature contains limited evidence regarding the possibility of silicone implants eliciting breast carcinoma. In this manuscript, we propose a theory in which the immune response to silicone breast implant gel bleeding acts as a triggering point for tumor oncogenesis in breast tissue. This hypothesis is derived from our findings of a case of invasive and undifferentiated medullary carcinoma in a patient with a silicone breast implant. The following concepts have been used to support this theory: 1) silicone bleeding from intact breast implants; 2) metaplasia: an adaptation to injury and precursor to dysplasia and cancer; 3) T-cell dysfunction in cancer immunity; 4) inhibitory cells in the tumor microenvironment (TME); 5) morphogenesis and bauplan; and 6) concepts underlying medullary carcinoma. We propose that the inflammatory process in response to silicone particles in the pericapsular glandular tissue favors the development of cellular mutations in specialized epithelial cells. This reverse morphogenesis could have resulted in breast carcinoma of the medullary type in the present case.

Finding the Needle in the Haystack: High-Resolution Techniques for Characterization of Mixed Protein Particles Containing Shed Silicone Rubber Particles Generated During Pumping.

During the manufacturing process of biopharmaceuticals, peristaltic pumps are employed at different stages for transferring and dosing of the final product. Commonly used silicone tubings are known for particle shedding from the inner tubing surface due to friction in the pump head. These nanometer sized silicone rubber particles could interfere with proteins. Until now, only mixed protein particles containing micrometer-sized contaminations such as silicone oil have been characterized, detected, and quantified. To overcome the detection limits in particle sizes of contaminants, this study aimed for the definite identification of protein particles containing nanometer sized silicone particles in qualitative and quantitative manner. The mixed particles consisted of silicone rubber particles either coated with a protein monolayer or embedded into protein aggregates. Confocal Raman microscopy allows label free chemical identification of components and 3D particle imaging. Labeling the tubing enables high-resolution imaging via confocal laser scanning microscopy and counting of mixed particles via Imaging Flow Cytometry. Overall, these methods allow the detection and identification of particles of unknown origin and composition and could be a forensic tool for solving problems with contaminations during processing of biopharmaceuticals.

“BLACK-MARKET” COSMETIC INJECTIONS IN A TRANSGENDER FEMALE RESULTING IN SILICONE EMBOLI SYNDROME AND INTERSTITIAL LUNG DISEASE

SESSION TITLE: Fellows Diffuse Lung Disease SESSION TYPE: Fellow Case Reports PRESENTED ON: October 18-21, 2020 INTRODUCTION: A thrombotic pulmonary embolism is a commonly encountered diagnosis that is often on the forefront of our minds when evaluating a patient with dyspnea. In direct contrast, nonthrombotic emboli are less frequently encountered, span a diverse set of etiologies, and involve varied pathogenesis, other than traditional mechanical obstruction as with ordinary pulmonary emboli. Septic, fat, talc, venous air, amniotic fluid, tumor, iodinated oil, mercury, hydatid, cotton, and catheter have all been described as different emboli involving the pulmonary circulation. We report a case of cosmetic injections with silicone and mineral oil in a transgender female resulting in silicone emboli syndrome and subsequent interstitial lung disease (ILD) and worsening hypoxia. CASE PRESENTATION: A 40 year old transgender female presented to our hospital with worsening dyspnea, cough, and hypoxemia over the course of a year. Her medical history was notable for multiple silicone and mineral oil cosmetic injections to her breasts, thighs, and buttocks, which the patient described as “black-market procedures.” The patient was hypoxic on presentation, requiring 3L of oxygen via nasal cannula, but otherwise was hemodynamically stable and afebrile. Her physical examination and laboratory studies were unremarkable. A chest radiograph revealed peripheral bibasilar reticular opacities. A CT chest showed diffuse reticulation, interlobular septal thickening, scattered nodules, and ground glass opacities. A bronchoscopy with bronchioalveolar lavage and transbronchial biopsies was performed. Pathology revealed spheroid silicone particles in the lung interstitium and capillaries, with histiocytic reaction and fibrosis. The diagnosis of interstitial lung disease due to silicone embolism syndrome was granted. The patient was trialed on steroids, without improvement in symptoms. She was discharged with supplemental oxygen with referral for lung transplant evaluation. DISCUSSION: Following subcutaneous injection, often from cosmetic procedures by nonmedical practitioners, liquid silicone enters the pulmonary circulation. Once in the pulmonary capillaries, interstitial inflammation, increased vascular permeability, alveolar edema and hemorrhage can ensue. Clinical features include hypoxia, dyspnea, fever, alveolar hemorrhage, and cough, with both acute and chronic presentations. CT findings of reticulonodular opacities and interlobular septal thickening are suggestive. Histopathology reveals globular deposits, alveolar inflammatory infiltrates, fibrosis, and hemorrhage. Treatment with steroids has been reported with favorable outcomes, however, severe cases can lead to ARDS and death. CONCLUSIONS: This case highlights the importance of a thorough exposure history when evaluating patients with ILD. Additionally, it is imperative to promote the awareness of this potentially lethal complication of cosmetic silicone injections. Reference #1: Zamora, A.C., Collard, H.R., Barrera, L. et al. Silicone Injection Causing Acute Pneumonitis: A Case Series. Lung 187, 241–244 (2009) Reference #2: Dawn, Samuel K. MD*; Elicker, Brett M. MD*; Leung, Jessica W. T. MD†; Reddy, Gautham P. MD, MPH*; Gotway, Michael B. MD‡ The Silicone Syndrome, Clinical Pulmonary Medicine: March 2006 - Volume 13 - Issue 2 - p 146-147. Reference #3: Sridhara S, Baksh M, Batool K, Chowdhury J, Reddy V, Norwood S, Sivaswami S. A rare case of delayed chronic pneumonitis following non-medical grade silicone injections in a transgender woman. J Unexplored Med Data 2018;3:1. DISCLOSURES: No relevant relationships by Astrid Carrion Rodriguez, source=Web Response No relevant relationships by Andrew Daya, source=Web Response No relevant relationships by Christine Girard, source=Web Response No relevant relationships by Nydia Martinez, source=Web Response No relevant relationships by Rajaganesh Rajagopalan, source=Web Response

Method to Determine Syringe Silicone Oil Layer Heterogeneity and Investigation of its Impact on Product Particle Counts

Prefilled syringes (PFSs) are commonly used for parenteral delivery of protein therapeutics. In PFSs, the inner surface of the syringe barrel is typically coated with silicone oil for lubrication. The total amount of silicone oil as well as its distribution can impact syringe functionality and particle formation. However, methods to non-destructively characterize the silicone oil distribution are limited. In this paper, we developed a method to visualize and quantify the relative distribution of silicone oil in unfilled syringes using a custom-built multi-color interferometric imaging system. We then applied the system in a preliminary study to investigate the impact of the silicone oil distribution on the number of particles formed in solution after filling and extrusion for two different types of syringes. The syringe type with significantly lower particle counts also exhibited significantly more homogeneous silicone oil distributions. Within syringe types, no significant association was found between silicone oil distribution and particle formation. Our method can be used in further studies that investigate the impact of syringe siliconization on PFS functionality and particle formation.

Evaluation of emulsified silicone oil with spectral domain-optical coherence tomography and fluorescein angiography.

To report emulsified particles and related complications after removal of silicone oil (SO) by spectral domain-optical coherence tomography (SD-OCT) and fluorescein angiography (FA). A prospective, single-center investigation was performed using SD-OCT, FA and flare cell photometry measurements to evaluate in a cohort of eyes with emulsified silicone particles after removal of long-term SO tamponade. Nineteen eyes of the 19 patients with emulsified silicone particles detected in ophthalmoscopic exam were included in the study: 13 (68%) were male, and 6 (31.6%) were female, and their mean age was 52.75 ± 16.06years. Preoperative diagnoses were rhegmatogenous retinal detachment in all eyes. The mean duration of the silicone oil's presence in the eye was found as 12.63 ± 4.87 (7-26) months. SD-OCT examination postoperatively showed small, round and hyper-reflective structures compatible with emulsified silicone particles on preretinal surface in 7 (36.8%) eyes, intraretinally in 6 (31.6%) eyes and in the vitreous in 12 (63%) eyes. FA imaging demonstrated pearl-like hyper-fluorescence at early and late phases on the large blood vessels in 9 (47.4%) eyes. Late phase hyper-fluorescence due to leakage on the macula was observed in 17 (89.5%) eyes. Diffuse peripheral leakage and hyper-fluorescence was detected in 11 (57.9%) eyes. Flare levels were higher in eyes with emulsified SO compared to unaffected fellow eyes (p < 0.05). Emulsified silicone particles that remain in the eye may lead to retinal complications and inflammation in addition to their known complications such as keratopathy and glaucoma. The particles that lead to inflammation and presence of inflammation may be examined by imaging methods such as SD-OCT and FA. Removing the SO before emulsification would be suitable for avoiding such complications.

Effect of Small Amount SiC on Mechanical Properties Composite Fabricated by Casting and Subsequent Rolling Process

Aluminum matrix composites (AMCs) are promising material to develope for engineering application in last a few decade. Combination between aluminum matrix and reinforced particles was succesfull increase the mechanical properties. Casting method have been used to fabricate the AMCs due to their simple process and low cost, however the nonuniform distribution elements and some defects were often observed in the microstructure by this traditional casting process. Furthermore, these problems have influenced the mechanical properties of composites. In other hand, the thermomechanical treatment and dispertion strengthening by particles such SiC are attractive technique to improved mechanical properties of composite such AMCs. Thermomechanical such rolling process was successfully modified the properties of composite, high energy from rolling machine induced plastic deformation and grain refinement of microstructure. The modification of this microstructure is the important role to enhance the mechanical properties. The aim of this research to investigate the effect of rolling process on microstructure and mechanical properties of aluminum cast reinforced with SiC particles. In the current work, Al-Si alloy ingot used as a matrix and reinforced with SiC particles for different composition (1.5, 2.0, 2.5 wt.%). Remelted ingot and SiC have been done in crucible grafite to prevent from contaminant. Composites material were fabricated by using pressure casting at 35 MPa, 657°C pouring temperature and the permanent mold made from mild steel with holding temperature 300°C. Further, a hot rolling process was performed at 550°C with 20% thickness reduction through multi pass process to obtain the thickess of sheets. The microstructure of composites were investigated by optical microscope (OM) with different magnification. Brinell hardness test was carried out to obtained the hardness on the surface of composites rolled. The impact test was conducted in room temperature by using charpy model. Furthermore, the ultimate tensile strength of composites were perfomed by universal tensile machine. The results shows the increase of SiC particles upto 2.5 wt.% promoted the finer microstructure was observed after rolled. Further, the sligthly increase both of hardness and tensile strength have been achieved after hot rolling with different silicone particle. The maximum hardness 71 HB of composite rolled was obtained for 2.5 wt.% SiC. The impact strength 19 joule was observed in 2.0 wt.% SiC and sligthly decrease with the increasing of silicone carbide. In other hand, the ultimate tensile strength 130 MPa was obtained for 2.5 wt.% SiC, the addition of a small amount SiC promote a slightly change the mechanical properties.

Preparation of free‐standing silicone particles in aqueous heterogeneous system

To prepare cross‐linked silicone (silicone rubber) particles in an aqueous medium, we investigated two synthesis methods involving a miniemulsion system. The first method was based on cationic ring‐opening polymerization of cyclic siloxane, which is a common synthetic route for linear silicone oil and uses octamethylcyclotetrasiloxane (D4) as the monomer and dimeric D4 (bis‐D4) as the cross‐linker. Although this method produces silicone particles, the particles do not remain in the particulate state after drying because of low cross‐linking density. The polymerization mechanism of this method was also investigated, which proceeds under the ring‐opening reaction of D4 in monomer droplets and upon polycondensation of hydrolyzed D4, which occurs in the water phase (ie, outside the monomer droplets). This mechanism implied that introducing the cross‐linking structure into particles is difficult because of the low solubility of bis‐D4 in water. To overcome these difficulties, we demonstrated a second method of preparing silicone particles based on the thiol‐Michael addition reaction between thiol‐terminated silicone oil and triacrylate in miniemulsion systems. Transmission electron microscopy images indicated that the silicone particles obtained in the particulate state upon drying and the aggregates of these particles showed elasticity.

Self-Limiting Processes in the Flame-Based Fabrication of Superhydrophobic Surfaces from Silicones.

Outdoor applications of superhydrophobic coatings require synthetic approaches that allow their simple, fast, scalable, and environmentally benign deployment on large, heterogeneous surfaces and their rapid regeneration in situ. We recently showed that the thermal degradation of silicones by flames fulfills these characteristics by spontaneously structuring silicone surfaces into a hierarchical, textured structure that provides wear-resistant, healable superhydrophobicity. This paper elucidates how flame processing-a simple, rapid, and out-of-equilibrium process-can be so counterintuitively reliable and robust in producing such a complex structure. A comprehensive study of the effect of the processing speed and flame temperature on the chemical and physical properties of the coatings yielded three surprising results. (i) Three thermal degradation mechanisms drive the surface texturing: depolymerization (in the O2-rich conditions of the surface), decomposition (in the O2-poor conditions found a few micrometers from the surface), and pyrolysis at excessive temperatures. (ii) The operational condition is delimited by the onset of the depolymerization at low temperatures and the onset of pyrolysis at high temperatures. (iii) The remarkably wide operational conditions and robustness of this approach result from self-limiting growth and oxidation of the silicone particles that are responsible for the surface texturing and in the extent of their deposition. As a result of this analysis we show that superhydrophobic surfaces can be produced or regenerated with this approach at a speed of 15 cm s-1 (i.e., the length of an airport runway in ∼4.5 h).

Theories of Etiopathogenesis of Breast Implant-Associated Anaplastic Large Cell Lymphoma.

Breast implant-associated anaplastic large cell lymphoma is a malignancy of T lymphocytes that is associated with the use of textured breast implants in both esthetic and reconstructive surgeries. Patients typically present with a delayed seroma 8-10 years following implantation or-less commonly-with a capsular mass or systemic disease. Current theories on disease pathogenesis focus on the interplay among textured implants, Gram-negative bacteria, host genetics, and time. The possible roles of silicone leachables and particles have been less well substantiated. This review aims to synthesize the existing scientific evidence regarding breast implant-associated anaplastic large cell lymphoma etiopathogenesis.

Novel amphiphilic polyvinylpyrrolidone functionalized silicone particles as carrier for low-cost lipase immobilization.

The high catalytic activity, specificity and stability of immobilized lipase have been attracting great interest. How to reduce the cost of support materials has always been a hot topic in this field. Herein, for the development of low-cost immobilized lipase, we demonstrate an amphiphilic polyvinylpyrrolidone (PVP) grafted on silicone particle (SP) surface materials (SP-PVP) with a rational design based on interfacial activation and solution polymerization. Meanwhile, hydrophilic pristine SP and hydrophobic polystyrene-corded silicone particles (SP-Pst) were also prepared for lipase immobilization. SP-PVP was characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and thermogravimetry. Our results indicated that the lipase loading amount on the SP-PVP composites was about 215 mg of protein per gram. In the activity assay, the immobilized lipase SP-PVP@CRL exhibited higher catalysis activity and better thermostability and reusability than SP@CRL and SP-Pst@CRL. The immobilized lipase retained more than 54% of its initial activity after 10 times of re-use and approximately trended to a steady rate in the following cycles. By introducing the interesting amphiphilic polymer to this cheap and easily obtained SP surface, the relative performance of the immobilized lipase can be significantly improved, facilitating interactions between the low-cost support materials and lipase.

Fe₃O₄⁻Silicone Mixture as Flexible Actuator.

In this study, we introduce Fe3O4-silicone flexible composite actuators fabricated by combining silicone and iron oxide particles. The actuators exploit the flexibility of silicone and the electric conductivity of iron oxide particles. These actuators are activated by electrostatic force using the properties of the metal particles. Herein, we investigate the characteristic changes in actuation performance by increasing the concentration of iron oxide from 1% to 20%. The developed flexible actuators exhibit a resonant frequency near 3 Hz and their actuation amplitudes increase with increasing input voltage. We found that the actuator can move well at metal particle concentrations >2.5%. We also studied the changes in actuation behavior, depending on the portion of the Fe3O4-silicone in the length. Overall, we experimentally analyzed the characteristics of the newly proposed metal particle-silicone composite actuators.

Encapsulation and controlled release of retinol from silicone particles for topical delivery

Retinol, a derivative of vitamin A, is a ubiquitous compound used to treat acne, reduce wrinkles and protect against conditions like psoriasis and ichthyosis. While retinol is used as the primary active ingredient (AI) in many skin care formulations, its efficacy is often limited by an extreme sensitivity to degrade and toxicity at high concentrations. While microencapsulation is an appealing method to help overcome these issues, few microencapsulation strategies have made a major translational impact due to challenges with complexity, cost, limited protection of the AI and poor control of the release of the AI. We have developed a class of silicone particles that addresses these challenges for the encapsulation, protection and controlled release of retinol and other hydrophobic compounds. The particles are prepared by the sol-gel polymerization of silane monomers, which enables their rapid and facile synthesis at scale while maintaining a narrow size distribution (i.e., CV < 20%). We show that our particles can: (i) encapsulate retinol with high efficiency (>85%), (ii) protect retinol from degradation (yielding a half-life 9× greater than unencapsulated retinol) and (iii) slowly release retinol over several hours (at rates from 0.14 to 0.67 μg cm−2 s−1/2). To demonstrate that the controlled release of retinol from the particles can reduce irritation, we performed a double blind study on human subjects and found that formulations containing our particles were 12–23% less irritating than identical formulations containing Microsponge® particles (an industry standard by Amcol, Inc.). To show that the silicone particles can elicit a favorable biological response, similar to the Microsponge® particles, we applied both formulations to reconstructed human epidermal tissues and found an upregulation of keratin 19 (K19) and a downregulation of K10, indicating that the reduced irritation observed in the human study was not caused by reduced activity. We also found a decrease in the production of interleukin-1α (IL-1α) compared to formulations containing the Microsponge particles, suggesting lower irritation levels and supporting the findings from the human study. Finally, we show that the silicone particles can encapsulate other AIs, including betamethasone, N, N-diethyl-meta-toluamide (DEET), homosalate and ingenol mebutate, establishing these particles as a true platform technology.

Performance of Knitted Fabrics Finished with Different Silicone Softeners

Silicone softeners make fabric soft, brilliant, greasy and more elastic, resulting is acceptable handle. In this research work, the effect of using different silicone softeners on pilling resistance and on some physical and mechanical properties of knitted fabrics was evaluated. Industrially applied silicone softeners of three different types (macro, semi-micro, micro) were used on fabrics knitted from different fiber materials (Egyptian cotton, Tencel LF, Tencel STD, bamboo, Modal and Micro-modal). The influence of using different silicone softeners on fabric pilling resistance, seam hole, air permeability, color strength, fastness to rubbing in wet and dry states and fastness to washing was investigated. Results have shown that the pilling performance of micro-modal fabrics finished with micro silicone is better than those finished with macro silicone. The higher number of fibers per cross-section for the micro modal yarns creates weak bonds between micromodal fibers and macro silicone particles. The macro silicone fabric has the greatest air permeability, while the micro silicone reduces the porosity of the yarn and increases air resistance. The macro silicone softener method has more fastness to color than the other finishing methods investigated.

Acoustic Fabrication via the Assembly and Fusion of Particles.

Acoustic assembly promises a route toward rapid parallel fabrication of whole objects directly from solution. This study reports the contact-free and maskless assembly, and fixing of silicone particles into arbitrary 2D shapes using ultrasound fields. Ultrasound passes through an acoustic hologram to form a target image. The particles assemble from a suspension along lines of high pressure in the image due to acoustic radiation forces and are then fixed (crosslinked) in a UV-triggered reaction. For this, the particles are loaded with a photoinitiator by solvent-induced swelling. This localizes the reaction and allows the bulk suspension to be reused. The final fabricated parts are mechanically stable and self-supporting.

Urethral injection therapy for urinary incontinence in women.

Urinary incontinence imposes a significant health and economic burden to society. Periurethral or transurethral injection of bulking agents is a minimally invasive surgical procedure used as one the surgical treatments of stress urinary incontinence (SUI) in adult women. To assess the effects of periurethral or transurethral injection therapy on the cure or improvement of urinary incontinence in women. We searched the Cochrane Incontinence Group Specialised Trials Register (searched 8 November 2010) and the reference lists of relevant articles. All randomised or quasi-randomised controlled trials of treatment for urinary incontinence in which at least one management arm involved periurethral or transurethral injection therapy. Two review authors independently assessed methodological quality of each study using explicit criteria. Data extraction was undertaken independently and clarification concerning possible unreported data sought directly from the investigators. Excluding duplicate reports, we identified 14 trials (excluding one that was subsequently withdrawn from publication and not included in this analysis) including 2004 women that met the inclusion criteria. The limited data available were not suitable for meta-analysis because they all came from separate trials. Trials were small and generally of moderate quality.One trial of 45 women that compared injection therapy with conservative treatment showed early benefit for the injectable therapy with respect to continence grade (risk ratio (RR) 0.70, 95% confidence interval (CI) 0.52 to 0.94) and quality of life (mean difference (MD) 0.54, 95% CI 0.16 to 0.92). Another trial, comparing Injection of autologous fat with placebo, terminated early because of safety concerns. Two trials that compared injection with surgical management found significantly better objective cure in the surgical group (RR 4.77, 95% CI 1.96 to 11.64; and RR 1.69, 95% CI 1.02 to 2.79), although the latter trial data did not reach statistical significance if an intention-to-treat analysis was used.Eight trials compared different agents and all results had wide confidence intervals. Silicone particles, calcium hydroxylapatite, ethylene vinyl alcohol, carbon spheres and dextranomer hyaluronic acid combination gave improvements which were not shown to be more or less efficacious than collagen. Dextranomer hyaluronic acid compound treated patients appeared to have significantly higher rates of injection site complications (16% with the hyaluronic acid compound versus none with collagen; RR 37.78, 95% CI 2.34 to 610.12) and this product has now been withdrawn from the market.A comparison of periurethral and transurethral methods of injection found similar outcomes but a higher (though not statistically significant) rate of early complications in the periurethral group. One trial of 30 women showed a weak (but not clinically significant) advantage for patient satisfaction (data not suitable for analysis in RevMan) after mid-urethral injection in comparison to bladder neck injection but with no demonstrable difference in continence levels. The available evidence base remains insufficient to guide practice. In addition, the finding that placebo saline injection was followed by a similar symptomatic improvement to bulking agent injection raises questions about the mechanism of any beneficial effects. One small trial comparing silicone particles with pelvic floor muscle training was suggestive of benefit at three months but it is not known if this was sustained, and the treatment was associated with high levels of postoperative retention and dysuria. Greater symptomatic improvement was observed with surgical treatments, though the advantages need to be set against likely higher risks. No clear-cut conclusions could be drawn from trials comparing alternative agents, although dextranomer hyaluronic acid was associated with more local side effects and is no longer commercially available for this indication. There is insufficient evidence to show superiority of mid-urethral or bladder neck injection. The single trial of autologous fat provides a reminder that periurethral injections can occasionally cause serious side effects. Also, a Brief Economic Commentary (BEC) identified three studies suggesting that urethral bulking agent might be more cost-effective compared with retropubic mid-urethral slings, transobturator or traditional sling procedure when used as an initial treatment in women without hypermobility or as a follow-up to surgery failure provided injection is kept minimal. However, urethral bulking agent might not be cost-effective when compared with traditional sling as an initial treatment of SUI when a patient is followed up for a longer period (15 months post-surgery).

A multi-topographical-instrument analysis: the breast implant texture measurement

Capsular contracture is a major complication after implant-based breast augmentation. To address this tissue reaction, most manufacturers texture the outer breast implant surfaces with calibrated salt grains. However, the analysis of these surfaces on sub-micron scales has been under-studied. This scale range is of interest to understand the future of silicone particles potentially released from the implant surface and the aetiology of newly reported complications, such as Anaplastic Large Cell Lymphoma.The surface measurements were accomplished by tomography and by two optical devices based on interferometry and on focus variation. The robustness of the measurements was investigated from the tissue scale to the cellular scale.The macroscopic pore-based structure of the textured implant surfaces is consistently measured by the three instruments. However, the multi-scale analyses start to be discrepant in a scale range between 50 µm and 500 µm characteristic of a finer secondary roughness regardless of the pore shape. The focus variation and the micro-tomography would fail to capture this roughness regime because of a focus-related optical artefact and of step-shaped artefact respectively.

Evaluation of the Effect of Plasma Treatment Frequency on the Activation of Polymer Particles

This study investigates the influence of treatment frequency (1–150 kHz) on the atmospheric plasma activation of both silicone and polyethylene terephthalate (PET) particles. These polymer particles with diameters in the range 3–5 mm, were treated using either helium or helium/oxygen gas mixtures, in a barrel atmospheric plasma system. The level of polymer particles activation was monitored using water contact angle measurements. The effect of plasma treatment frequency on barrel heating was monitored using an infrared thermographic camera, the maximum barrel temperature after 15 min treatment was found to be 98 °C at a frequency of 130 kHz. Optical emission spectroscopy was used as a diagnostic tool to monitor changes in atomic and molecular species spectral intensity with experimental conditions, as well as a change in electron energy distribution function. Electrical characterisation studies demonstrated an increase in plasma power with increasing frequency, in the range investigated. X-ray photoelectron spectroscopy analysis indicate an increase of oxygen content on polymer surfaces after plasma treatment. For silicone particles, the minimum polymer water contact angle was obtained by using a frequency of 130 kHz. After 15 min treatment time, the water contact angle decreased from 141° to 11°. While for PET particles the optimum treatment frequency was found to be 70 kHz, resulting in a water contact angle decreased from 94° to 32°. This lower frequency was used due to the partial melting of the PET (Tg of 80 °C), when treated at the higher frequency.

All-silicone elastic composites with counter-intuitive piezoelectric response, designed for electromechanical applications

PDMS-based stretchable elastomeric composites with cross-linked polar silicone particles as fillers exhibit piezoresponse, improved dielectric properties and tunable mechanical behaviour.