Sol-Gel Science and Technology – Commercial Applications

In the June 2020 issue of the ISGS Newsletter, we presented an overview of the current state of sol-gel science and technology that focussed on publications during the past decade in the academic and patent literature. In the August issue, we present the first of an ongoing series of articles addressing the conversion of this extraordinarily diverse knowledge base into commercial products.

As articulated by the organisers of the 20 th Anniversary International Sol-Gel Conference held in St Petersburg during August 2019 (see V. Vinogradov, D. Avnir, V. Kessler and D. Koslova, Journal of Sol-Gel Science and Technology, 95(3), 493 (2020)), the scope pf the papers presented at the conference demonstrated that “sol-gel materials have entered every aspect of modern life”. This perspective is certainly reflected in the range of technological domains in which sol-gel technology has been patented over the past decade. However, it is the conversion of these patents into commercial products that is required to ensure that sol-gel products have a positive impact on the daily lives of consumers.

A recent report has indicated that the market for sol-gel products is segmented by application type (e.g. coatings, catalysts, piezoelectrics, etc) and industry (e.g. automotive, electronics, health, aerospace, etc). As anticipated from the patent literature, coatings remain the most established and mature commercial application domain for sol-gel processing, with technological advances in the automotive and aerospace industries predicted to increase the demand for sol-gel-based coatings. The value of the global market for sol-gel coatings in 2018 was estimated to be US$2.23B, increasing to over US$5.2B by 2026. Selected multinational companies driving this growth include Schott AG, BASF SE, 3M, Axalta Coating Systems, Fuji Silysia Chemical Ltd, Dow, Premium Coatings and Chemicals Pvt Ltd, Akzo Nobel, Socomore, PPG Industries, CMR Coatings GmbH, Nanovations, Chase Corporation, etc.

In addition to these large international corporations with mature product lines embedding sol-gel science and technology, a number of smaller companies and start-ups have entered the market to commercialise sol-gel innovations that have the potential to enhance the societal impact of the work of the sol-gel community. Selected examples of the achievements of these smaller innovators, who are critically important to the developing “ecosystem” of emerging sol-gel products, are presented below to illustrate the diverse product areas being explored, with others to be highlighted in future issues of the ISGS Newsletter.

Sol-Gel Advanced Topical Therapies (Israel) is a clinical-stage dermatology company focused on identifying, developing, and commercializing topical drug products for the treatment of skin diseases, based on their propriety silica-based controlled-delivery technology. Their product pipeline includes two products that have proceeded to Phase III clinical trials:

• Epsolay, a topical cream containing encapsulated benzoyl peroxide for the treatment of papulopustular rosacea.

• Twyneo a combination of benzoyl peroxide and tretinoin for the treatment of acne vulgaris. Tretinoin and benzoyl peroxide are often prescribed together, however, they have not yet been marketed as a combination product because benzoyl peroxide degrades tretinoin when they are combined in the same formulation. In the case of Twyneo, each ingredient is independently encapsulated in silica matrices that release the ingredients in a controlled manner.

An additional three products are currently at the preclinical or research stage.

Ceramisphere and Ceramisphere Health (Australia) (a recent spinoff from Ceramisphere) are developing product pipelines exploiting the use of porous silica for the controlled encapsulation and release of actives. The main products under development include:

Inhibispheres, which are sub-micron-sized nanoparticles such as silica, in which active components (e.g. corrosion inhibitors) can be incorporated within the nanoparticle matrix. The resulting materials are sufficiently robust to enable them to be mixed directly into paints or coating formulations, thus providing both corrosion protection and self-healing without impacting the mechanical or optical properties of the coated surface.

Lidocaine patch, in which lidocaine is incorporated into a sol-gel-based nanocomposite. A key advantage of the approach used is that the patch provides similar release rates to current commercial lidocaine patches, but with much lower doses and residual drug remaining in the used patch.

Fentanyl (controlled drug) patch, which avoid many of the issues associated with current approaches for transdermal delivery of opioids and reduces the risks arising from accidental overdose, improper disposal, etc.

Epidermal growth factor (EGF) patch, in which EGF is encapsulated within a silica-based matrix. Sustained EGF release from the silica matrix has been shown to promote superior wound healing compared to unencapsulated EGF.

SolGelWay (France) has developed a range of sol-gel coating technologies for diverse applications. These include absorbing optical coatings for maximising the efficiency of solar thermal systems; hydrophobic and oleophobic coatings; antireflective coatings for polymers; heterogeneous nanopatterned inorganic surfaces; photocatalytic and UV protective coatings for polymers; thick, porous coatings from aqueous feedstocks; thickness graded coatings for applications in optics and microfluidics; optical films with ultralow dielectric constants; water-repellent and self-cleaning films; and feedstocks for soft nanoimprint lithography. The company also markets turnkey solutions and services for sol-gel applications.

CaptiGel (Sweden) has developed a sol-gel platform for the encapsulation and controlled release of biomolecules and microorganisms, which involves the formation of a titania-based shell to encapsulate the active component. Release is triggered either chemically or biochemically, and the titania shell can be functionalised to provide UV resistance for the encapsulated payload. Potential market domains for the technology include pharmaceuticals (in particular for wound dressings and sprays for both human and veterinary medicine), cosmetics, agriculture and forestry.

Aqua Diagnostics (Australia) markets instruments for analysing the chemical oxygen demand (COD) of water samples, which is an important parameter in optimising the operation of water treatment plans and environmental monitoring. The company has developed and implemented a photoelectrochemical approach for such measurements, in which the photocurrent arising from the oxidation of organic species in the sample is correlated to the quantity of organics present. The key component in this system is a patented photoelectrode consisting of a conducting substrate with immobilised titania nanoparticles produced by sol-gel processing.