-
Aesthetic Surgery Journal Feb 2019Surgical applications using breast implants are individualized operations to fill and shape the breast. Physical properties beyond shape, size, and surface texture are...
BACKGROUND
Surgical applications using breast implants are individualized operations to fill and shape the breast. Physical properties beyond shape, size, and surface texture are important considerations during implant selection.
OBJECTIVES
Compare form stability, gel material properties, and shell thickness of textured shaped, textured round, and smooth round breast implants from 4 manufacturers: Allergan, Mentor, Sientra, and Establishment Labs, through bench testing.
METHODS
Using a mandrel height gauge, form stability was measured by retention of dimensions on device movement from a horizontal to vertical supported orientation. Dynamic response of the gel material (gel cohesivity, resistance to gel deformation, energy absorption) was measured using a synchronized target laser following application of graded negative pressure. Shell thickness was measured using digital thickness gauge calipers.
RESULTS
Form stability, gel material properties, and shell thickness differed across breast implants. Of textured shaped devices, Allergan Natrelle 410 exhibited greater form stability than Mentor MemoryShape and Sientra Shaped implants. Allergan Inspira round implants containing TruForm 3 gel had greater form stability, higher gel cohesivity, greater resistance to gel deformation, and lower energy absorption than those containing TruForm 2 gel and in turn, implants containing TruForm 1 gel. Shell thickness was greater for textured vs smooth devices, and differed across styles.
CONCLUSIONS
Gel cohesivity, resistance to gel deformation, and energy absorption are directly related to form stability, which in turn determines shape retention. These characteristics provide information to aid surgeons choosing an implant based on surgical application, patient tissue characteristics, and desired outcome.
Topics: Breast Implants; Materials Testing; Prosthesis Design; Silicone Gels
PubMed: 29718087
DOI: 10.1093/asj/sjy103 -
Acta Ophthalmologica May 2021Silicone oil (SO) has been used as a long-term tamponade agent in the treatment of complicated vitreoretinal diseases for about half a century, during which time many... (Review)
Review
Silicone oil (SO) has been used as a long-term tamponade agent in the treatment of complicated vitreoretinal diseases for about half a century, during which time many advances in surgical techniques and technologies have been made. This review summarizes the chemical and physical properties of SO, its indications and complications, including particularly emulsification. The mechanisms and risk factors for emulsification are discussed, as well as novel strategies for its effective removal. Finally, the review focuses on new improved formulations of SO, including research into slow-release pharmacological agents within SO and provides an overview of alternatives to SO for the purpose of long-term tamponade that are being developed.
Topics: Endotamponade; Humans; Silicone Oils; Vitreoretinal Surgery
PubMed: 32930501
DOI: 10.1111/aos.14604 -
Journal of Biomedical Materials... Aug 2022Contact lenses are one of the most successful biomaterials in history with a global market estimated to be worth over $17 billion in 2025. Silicone hydrogel contact...
Contact lenses are one of the most successful biomaterials in history with a global market estimated to be worth over $17 billion in 2025. Silicone hydrogel contact lenses dominate the market and are complex biphasic biomaterials with several critical material properties needed for clinical use. Careful consideration of composition and chemistry is needed to identify formulations of lenses meeting all commercial standards with the potential for improved manufacturability, cost, and/or next generation use. Four silicone macromers were investigated in this work with varying symmetry of siloxane units and macromer structure, number of siloxane groups, branching, length, and concentration. Novel silicone hydrogel lenses were produced and evaluated for optical transmittance, elastic modulus, oxygen transmissibility, water content, and surface wettability. Several lenses met commercial standards and demonstrated an increase in oxygen permeability (Dk) and inverse relationship with elastic modulus and siloxane concentration, respectively. A hydrophobic/hydrophilic ratio below 1.4 was needed for a co-continuous water phase. Substitution of methoxypropyl groups for butyl groups increased hydrophobic microdomains leading to decreased optical quality and mechanical properties. Generally, fluorine-containing silicone macromers allowed for a wider range of successful compositions, and above a certain hydrophilic composition, the presence of trifluoropropyl groups resulted in improved solubility and optically clear lenses. Data also showed asymmetric siloxane macromers have potential to meet critical lens properties at lower overall siloxane content. New lens materials with wider composition ranges meeting all clinical lens properties is a significant challenge and may significantly expand the field.
Topics: Biocompatible Materials; Contact Lenses; Hydrogel, Polyethylene Glycol Dimethacrylate; Hydrogels; Oxygen; Silicones; Siloxanes; Water
PubMed: 35366061
DOI: 10.1002/jbm.a.37389 -
Translational Vision Science &... Jul 2021To investigate the behavior of silicone oil (SiO) at the steady equilibrium and during saccades and calculate SiO-retina contact, shear stress (SS), and shear rate (SR).
PURPOSE
To investigate the behavior of silicone oil (SiO) at the steady equilibrium and during saccades and calculate SiO-retina contact, shear stress (SS), and shear rate (SR).
METHODS
A 24 mm phakic eye mesh model underwent 50°/0.137s saccade. The vitreous chamber compartment was divided into superior and inferior 180° sectors: lens, pre-equator, postequator, and macula. SiO-retina contact was evaluated as a function of fill percentages between 80% and 90% for a standing patient, 45° upward gaze, and supine. SS and SR for 1000 mPa-s (SiO1000) and 5000 mPa-s (SiO5000) silicon oil were calculated.
RESULTS
SiO fill between 80% to 90% allowed 55% to 78% retinal contact. The superior retina always kept better contact with SiO, regardless of the fill percentage (P < 0.01). SiO interface thoroughly contacted the macula only in standing position. SS followed a bimodal behavior and was always significantly higher for SiO5000 compared to SiO1000 (P < 0.01) throughout the saccade. The macula suffered the highest mean SS in standing position, while throughout the saccade the average SS was maximum at the SiO-aqueous interface. SR was significantly higher for SiO1000 compared to SiO5000 (P < 0.001).
CONCLUSIONS
SS on the retinal surface may instantaneously exceed reported retinal adhesiveness values especially at the SiO-aqueous interface and possibly favor redetachment. Despite 90% SiO fill the inferior retina remains extremely difficult to tamponade.
TRANSLATIONAL RELEVANCE
Accurate assessment of retina-tamponade interaction may explain recurrent inferior retinal redetachment, silicone oil emulsification, and help to develop better vitreous substitutes.
Topics: Humans; Hydrodynamics; Retina; Retinal Detachment; Silicone Oils; Vitrectomy
PubMed: 34313726
DOI: 10.1167/tvst.10.8.22 -
Environment International Nov 2022Personal chemical exposure assessment is necessary to determine the frequency and magnitude of individual chemical exposures, especially since chemicals present in... (Review)
Review
Personal chemical exposure assessment is necessary to determine the frequency and magnitude of individual chemical exposures, especially since chemicals present in everyday environments may lead to adverse health outcomes. In the last decade, silicone wristbands have emerged as a new chemical exposure assessment tool and have since been utilized for assessing personal exposure to a wide range of chemicals in a variety of populations. Silicone wristbands can be powerful tools for quantifying personal exposure to chemical mixtures in a single sample, associating exposure with health outcomes, and potentially overcoming some of the challenges associated with quantifying the chemical exposome. However, as their popularity grows, it is crucial that they are used in the appropriate context and within the limits of the technology. This review serves as a guide for researchers interested in utilizing silicone wristbands as a personal exposure assessment tool. Along with briefly discussing the passive sampling theory behind silicone wristbands, this review performs an in-depth comparison of wristbands to other common exposure assessment tools, including biomarkers of exposure measured in biospecimens, and evaluates their utility in exposure assessments and epidemiological studies. Finally, this review includes recommendations for utilizing silicone wristbands to evaluate personal chemical exposure and provides suggestions on what research is needed to recognize silicone wristbands as a premier chemical exposure assessment tool.
Topics: Biomarkers; Environmental Monitoring; Knowledge; Silicones
PubMed: 36116363
DOI: 10.1016/j.envint.2022.107339 -
The British Journal of Dermatology Aug 2020
Topics: Bandages; Heel; Humans; Intensive Care Units; Pressure Ulcer; Silicones
PubMed: 32323310
DOI: 10.1111/bjd.19061 -
Chemistry, An Asian Journal May 2022In this review, we describe recent progress on stimuli-responsive hybrid materials based on polyhedral oligomeric silsesquioxane (POSS) and their applications as a... (Review)
Review
In this review, we describe recent progress on stimuli-responsive hybrid materials based on polyhedral oligomeric silsesquioxane (POSS) and their applications as a chemical sensor. In particular, we explain the unique functions originating from molecular assembly concerning POSS-containing soft materials mainly from our studies. POSS has an inorganic cubic core composed of silicon-oxygen (Si-O) bonds and organic substituents at each vertex. Owing to intrinsic properties of POSS, such as high thermal stability, rigidity, and low chemical reactivity, various robust hybrid materials have been developed. From the numerous numbers of POSS hybrids, we herein focus on the environment-sensitive optical materials in which molecular assembly of POSS itself and functional units connected to POSS should be a key factor for expressing material properties. We also explain the mechanisms of chemical sensors originating from these stimuli-responsive optical properties. Stimuli-responsive excimer emission and pollutant detectors, nanoplastic sensors with the water-dispersive POSS networks, trans fatty acid sensors, turn-on luminescent sensors for aerobic condition and fluoride anion sensors are described. We also mention the mechanochromic polyurethane hybrids and the thermally-durable mechanochromic luminescent materials. The roles of the unique optical properties from soft materials composed of rigid POSS, which doesn't have significant light-absorption and emission properties in the visible region, are surveyed.
Topics: Organosilicon Compounds; Polyurethanes
PubMed: 35322576
DOI: 10.1002/asia.202200144 -
Scientific Reports Sep 2023The development of wearable bioelectronic systems is a promising approach for optimal delivery of therapeutic treatments. These systems can provide continuous delivery...
The development of wearable bioelectronic systems is a promising approach for optimal delivery of therapeutic treatments. These systems can provide continuous delivery of ions, charged biomolecules, and an electric field for various medical applications. However, rapid prototyping of wearable bioelectronic systems for controlled delivery of specific treatments with a scalable fabrication process is challenging. We present a wearable bioelectronic system comprised of a polydimethylsiloxane (PDMS) device cast in customizable 3D printed molds and a printed circuit board (PCB), which employs commercially available engineering components and tools throughout design and fabrication. The system, featuring solution-filled reservoirs, embedded electrodes, and hydrogel-filled capillary tubing, is assembled modularly. The PDMS and PCB both contain matching through-holes designed to hold metallic contact posts coated with silver epoxy, allowing for mechanical and electrical integration. This assembly scheme allows us to interchange subsystem components, such as various PCB designs and reservoir solutions. We present three PCB designs: a wired version and two battery-powered versions with and without onboard memory. The wired design uses an external voltage controller for device actuation. The battery-powered PCB design uses a microcontroller unit to enable pre-programmed applied voltages and deep sleep mode to prolong battery run time. Finally, the battery-powered PCB with onboard memory is developed to record delivered currents, which enables us to verify treatment dose delivered. To demonstrate the functionality of the platform, the devices are used to deliver H[Formula: see text] in vivo using mouse models and fluoxetine ex vivo using a simulated wound environment. Immunohistochemistry staining shows an improvement of 35.86% in the M1/M2 ratio of H[Formula: see text]-treated wounds compared with control wounds, indicating the potential of the platform to improve wound healing.
Topics: Animals; Mice; Wound Healing; Capillary Tubing; Dimethylpolysiloxanes; Disease Models, Animal
PubMed: 37679425
DOI: 10.1038/s41598-023-41572-w -
The Plant Journal : For Cell and... Apr 2016Traditional method of Agrobacterium-mediated transformation through the generation of tissue culture had limited success for Setaria viridis, an emerging C4 monocot...
Traditional method of Agrobacterium-mediated transformation through the generation of tissue culture had limited success for Setaria viridis, an emerging C4 monocot model. Here we present an efficient in planta method for Agrobacterium-mediated genetic transformation of S. viridis using spike dip. Pre-anthesis developing spikes were dipped into a solution of Agrobacterium tumefaciens strain AGL1 harboring the β-glucuronidase (GUS) reporter gene driven by the cauliflower mosaic virus 35S (CaMV35S) promoter to standardize and optimize conditions for transient as well as stable transformations. A transformation efficiency of 0.8 ± 0.1% was obtained after dipping of 5-day-old S3 spikes for 20 min in Agrobacterium cultures containing S. viridis spike-dip medium supplemented with 0.025% Silwet L-77 and 200 μm acetosyringone. Reproducibility of this method was demonstrated by generating stable transgenic lines expressing β-glucuronidase plus (GUSplus), green fluorescent protein (GFP) and Discosoma sp. red fluorescent protein (DsRed) reporter genes driven by either CaMV35S or intron-interrupted maize ubiquitin (Ubi) promoters from three S. viridis genotypes. Expression of these reporter genes in transient assays as well as in T1 stable transformed plants was monitored using histochemical, fluorometric GUS activity and fluorescence microscopy. Molecular analysis of transgenic lines revealed stable integration of transgenes into the genome, and inherited transgenes expressed in the subsequent generations. This approach provides opportunities for the high-throughput transformation and potentially facilitates translational research in a monocot model plant.
Topics: Acetophenones; Agrobacterium tumefaciens; Genes, Reporter; Organosilicon Compounds; Plant Leaves; Plants, Genetically Modified; Promoter Regions, Genetic; Reproducibility of Results; Seedlings; Seeds; Setaria Plant; Transformation, Genetic; Transgenes
PubMed: 26932666
DOI: 10.1111/tpj.13148 -
International Journal of Nanomedicine 2023The respiratory system is intensely damaged by acute lung injury (ALI). The anti-inflammatory effects of tetramethylpyrazine (TMP) against ALI have been confirmed, but...
BACKGROUND
The respiratory system is intensely damaged by acute lung injury (ALI). The anti-inflammatory effects of tetramethylpyrazine (TMP) against ALI have been confirmed, but it exhibits a short half-life. miR-194-5p could directly target Rac1, but the internalization rate of miRNA cells was low.
PURPOSE
To explore the potential of the soft mesoporous organic silica nanoplatform (NPs) as carriers for delivery of TMP and miR-194-5p through the tail vein.
METHODS
NPs@TMP and NPs@PEI@miR-194-5p were added to the HUVEC cell-lines, in vitro, to observe the cell uptake and cytotoxic effects. In vivo experiments were conducted by injecting fluorescently labeled NPs through the tail vein and tracking distribution. Therapeutic and toxic side-effects were analyzed systemically.
RESULTS
In vitro study exhibited that NPs have no toxic effect on HUVECs within the experimental parameters and have excellent cellular uptake. The IVIS Spectrum Imaging System shows that NPs accumulate mainly in the lungs. NPs@TMP treatment can improved oxidative stress and inflammation levels in ALI mice and inhibited the TLR4/NLRP3/caspase 1 pathway. NPs@PEI@miR-194-5p can inhibit the Rac1/ZO-1/occludin pathway and improved endothelial cell permeability in ALI mice. The co-treatment of NPs@TMP and NPs@PEI@miR-194-5p can significantly improved the survival rates of the mice, reduced pulmonary capillary permeability and improved pathological injury in ALI mice.
INNOVATION
This study combined traditional Chinese medicine, bioinformatics, cellular molecular biology and nanobiomedicine to study the pathogenesis and treatment of ALI. The rate of cellular internalization was improved by changing the shape and hardness of nanoparticles. NPs@TMP and NPs@PEI@miR-194-5p combined application can significantly improve the survival condition and pathological injury of mice.
CONCLUSION
NPs loaded with TMP and miR-194-5p showed a greater therapeutic effect in ALI mice.
Topics: Animals; Humans; Mice; Acute Lung Injury; Human Umbilical Vein Endothelial Cells; Lipopolysaccharides; Lung; MicroRNAs; Organosilicon Compounds; Pyrazines
PubMed: 38026537
DOI: 10.2147/IJN.S420802