Morphological Properties of Siloxane-Hydrogel Contact Lens Surfaces

Stach, Sebastian; Ţălu, Ștefan; Trabattoni, Silvia; Tavazzi, Silvia; Głuchaczka, Alicja; Siek, Patrycja; Zajac, Jozef; Giovanzana, Stefano

doi:10.1080/02713683.2016.1217546

Cited by 14 publications

(6 citation statements)

References 22 publications

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“…As such, this material has been of interest in developing ophthalmic treatments, such as lubricating solution [154] or contact lens modification [155]. The incorporation of HA was shown not to affect the surface morphology of the CL even after 12 h of wear, showing the stability of these modifications [156]. HA is typically a graft/encapsulating material to other established CL hydrogels.…”

Section: Contact Lens Materialsmentioning

confidence: 99%

Contact Lens Materials: A Materials Science Perspective

2019

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More is demanded from ophthalmic treatments using contact lenses, which are currently used by over 125 million people around the world. Improving the material of contact lenses (CLs) is a now rapidly evolving discipline. These materials are developing alongside the advances made in related biomaterials for applications such as drug delivery. Contact lens materials are typically based on polymer- or silicone-hydrogel, with additional manufacturing technologies employed to produce the final lens. These processes are simply not enough to meet the increasing demands from CLs and the ever-increasing number of contact lens (CL) users. This review provides an advanced perspective on contact lens materials, with an emphasis on materials science employed in developing new CLs. The future trends for CL materials are to graft, incapsulate, or modify the classic CL material structure to provide new or improved functionality. In this paper, we discuss some of the fundamental material properties, present an outlook from related emerging biomaterials, and provide viewpoints of precision manufacturing in CL development.

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Section: Contact Lens Materialsmentioning

confidence: 99%

Contact Lens Materials: A Materials Science Perspective

2019

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“…Commercial CLs made of Filcon V (Safilens, Italy) containing dimethyl‐acrylamide, tris‐trimethylsilys, poly‐(dimethyl‐siloxane)‐dimethacrylate, ethyleneglycol‐dimethacrylate, and phthalocyanine copper were studied (Stach et al, 2017, 2019). The characteristics of analyzed CLs (power ranging from −1.00 D to −4.00 D) are the following: FDA group, I; content of water, 49%; O 2 Dk/t, 5.3 × 10 −14 m s −1 Pa −1 ; Young's modulus, 7.06 × 10 5 Pa; and tensile strength, 2.14 × 10 6 Pa.…”

Section: Methodsmentioning

confidence: 99%

“…Several studies have examined the surface properties and local topography of CLs before and after wear (Abadías, Serés, & Torrent‐Burgués, 2015; González‐Méijome, López‐Alemany, Almeida, & Parafita, 2009; Lira, Santos, Azeredo, Yebra‐Pimentel, & Oliveira, 2008) using different advanced imaging techniques (Stach et al, 2017, 2019).…”

Section: Introductionmentioning

confidence: 99%

Advanced morphological analysis of siloxane‐hydrogel contact lenses

Ţălu

2021

Microscopy Res & Technique

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The purpose of this work is to provide a better understanding of three‐dimensional (3‐D) surface texture of siloxane‐hydrogel contact lenses (CLs) using atomic force microscopy (AFM) and stereometric analysis. The 3‐D surface texture characterization of unworn/worn siloxane‐hydrogel CLs made of Filcon V (I FDA group) was performed with stereometric analysis. The atomic force microscopy (AFM) measurements of surface roughness and micromorphology of CLs were made using a Nanoscope V MultiMode (Bruker) in intermittent‐contact mode, in air, on square areas of 5 × 5 μm. Stereometric study of 3‐D surface texture was made according with ISO 25178‐2:2012 for CLrins (taken from the blister and rinsed with deionized water); CLss (preserved for 12 hr in saline solution and rinsed with deionized water); CLworn‐smooth (worn for 8 hr and presenting the smooth type morphology), and CLworn‐sharp (worn for 8 hr and presenting the sharp‐type morphology). The 3‐D surface texture of siloxane‐hydrogel CLs was found to have specific morphological characteristics. Statistical parameters revealed local geometrical and morphological spatial structures at nanometer scale attributed to the specific interactions at the CLs surface. Before wear, the surface micromorphology of Filcon V CLs is regular with uniformly distributed microasperities and relatively small heights (Sq = 0.6 nm). After 12 hr in saline, it is found that the micromorphology changes relatively easily, but retaining the main morphological characteristics (Sq = 1.2 nm). After 8 hr of wear, there are two typical micromorphologies: smooth type, characterized by gutter structures and isolated microasperities (Sq = 2.5 nm), while the sharp type has an appearance with compactly arranged microasperities of hill type flanked by compactly arranged microregions of valley type (Sq = 2.2 nm). Surface statistical parameters allow manufacturers in developing the next generation of CLs with improved surface texture while improving biocompatibility and minimizing the impact of the material on corneal physiology. Furthermore, the micro‐elastohydrodynamic lubrication due to surface texture at a nanometer scale between the back surface of the CL with the corneal surface and the front surface of the CL with the under‐surface of the eyelid can be deeper and more nuanced to understand in light of modern tribological theories.

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“…AFM, SEM and confocal microscopy are other less used high-resolution techniques to characterize the morphology of hydrogels. Even so, AFM can provide information about the surface properties of the nonconductive materials by creating a topographic image of the hydrogel surface, and SEM can give the conformation of a gel by imaging biomolecules in their native conditions without preparation, and finally, confocal microscopy gives improved high-quality images by acquiring point-by-point images and allowing 3D reconstruction of complex fluorescent morphologies [65,66]. AFM, SEM and confocal microscopy are other less used high-resolution techniques to characterize the morphology of hydrogels.…”

Section: Structural/morphological Characterizationmentioning

confidence: 99%

Injectable Hydrogels: From Laboratory to Industrialization

Alonso¹,

Olmo²,

González³

et al. 2021

Polymers

116

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The transfer of some innovative technologies from the laboratory to industrial scale is many times not taken into account in the design and development of some functional materials such as hydrogels to be applied in the biomedical field. There is a lack of knowledge in the scientific field where many aspects of scaling to an industrial process are ignored, and products cannot reach the market. Injectable hydrogels are a good example that we have used in our research to show the different steps needed to follow to get a product in the market based on them. From synthesis and process validation to characterization techniques used and assays performed to ensure the safety and efficacy of the product, following regulation, several well-defined protocols must be adopted. Therefore, this paper summarized all these aspects due to the lack of knowledge that exists about the industrialization of injectable products with the great importance that it entails, and it is intended to serve as a guide on this area to non-initiated scientists. More concretely, in this work, the characteristics and requirements for the development of injectable hydrogels from the laboratory to industrial scale is presented in terms of (i) synthesis techniques employed to obtain injectable hydrogels with tunable desired properties, (ii) the most common characterization techniques to characterize hydrogels, and (iii) the necessary safety and efficacy assays and protocols to industrialize and commercialize injectable hydrogels from the regulatory point of view. Finally, this review also mentioned and explained a real example of the development of a natural hyaluronic acid hydrogel that reached the market as an injectable product.

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Morphological Properties of Siloxane-Hydrogel Contact Lens Surfaces

Cited by 14 publications

References 22 publications

Contact Lens Materials: A Materials Science Perspective

Contact Lens Materials: A Materials Science Perspective

Advanced morphological analysis of siloxane‐hydrogel contact lenses

Injectable Hydrogels: From Laboratory to Industrialization

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