The consumer has difficulty in understanding the cosmetic industry’s current sun protection message. SPF & UVA are not well understood by the normal sunscreen user. The cosmetic industry itself is not always clear in its message to the consumer. The more recent industry conversations around infra-red, blue light & visible light further complicate the sun protection message.
Thus, to many the high mortality rate from UV ray associated melanomas, one person dies of melanoma every hour & 86% of melanomas are caused by UV rays from the sun is of little surprise. It stands to reason that the sun protection market is very active in terms of educating consumers & improving products for consumers.

Sunscreens currently available on the market contain one of two types of UV-filters, chemical or mineral. The chemical sunscreens are under increasing scrutiny due to events such as those recently in Hawaii & this has increased the markets openness to using mineral sunscreens. Chemical sunscreens use chemical ingredients to absorb & dissipate UV rays while the active ingredients in mineral sunscreens form a physical filter that deflects & scatters UV rays. Chemical sunscreens are coming under scrutiny as they only cover a narrow spectrum of sun ray protection, predominantly UVB rays & not the perhaps more harmful UVA rays which can cause skin cancers. There are also higher instances of allergic reactions to sunscreens with chemical UV filters, resulting in skin irritations. Chemical filters also have low photostability, so they degrade or destabilise over time when exposed to sunlight.

Broad spectrum sunscreens that can protect against UVA & UVB rays are seen by many to be the future in sun protection philosophy for formulators. Only sunscreens with physical mineral filters can offer broad spectrum protection & have considerably higher photostability. The two mineral UV filters available on the market are Zinc Oxide (ZnO) & Titanium Dioxide (TiO2). Zinc Oxide is a globally approved natural mineral ingredient, considered the most effective UV filter in broad spectrum sunscreen, providing extensive protection against both UVA & UVB rays.

Conventional ZnO Forms

The two current conventional forms of ZnO used in sunscreen products are of micron & nano particle size. In the micron formulations of ZnO the particles are bigger in size range of 2 to 10 µm while the smaller particle size in the nano formulations range from 10 to 40 nm.

Comparison of the particle sizes of ZnO in the micron & nano forms

There are benefits & disadvantages to each of the micron or nano forms of ZnO. Some formulators consider Micron ZnO has better health & safety features; however, nano ZnO is considered a more effective sunscreen & is thus more commonly used by formulators.

Nano ZnO is a more effective sunscreen additive than micron ZnO, as it provides a higher protection to UV rays per percentage & can cover a higher surface area per percentage. It also forms a more visually & aesthetically pleasing sunscreen since it has a high level of transparency. These features however, depend on the particles not agglomerating, which is a problem for nano ZnO, as it exhibits a very high level of uncontrolled agglomeration. Micron ZnO has also been shown to exhibit uncontrolled agglomeration.

Micron ZnO is considered to be relatively safer compared to nano ZnO due to its larger particle size. The small particles in the nano form may be highly toxic to humans & highly phytotoxic as they can penetrate through the skin of humans & accumulate in the roots of plants. Micron ZnO also has an advantage over nano ZnO in that it offers more effective protection against high energy visible light & blue light. While this isn’t a major area of focus at the moment for sun protection products it is a recent trend & a possible area of expansion for the future.

MicNo®-ZnO; A Novel ZnO With All The Benefits of Both Micron & Nano ZnO

MicNo-ZnO technology from Entekno Materials is a novel mineral-based UV filter. Created by patented MicNo particle technology it combines the benefits of both micron & nano ZnO particles. MicNo-ZnO is a tailored, platelet shaped, micron sized particle composed of nano primary particles. MicNo acts like micron ZnO over the skin, since it does not penetrate through the skin, but it still offers the transparent protection of nano ZnO.

Protection from UV rays by % mass is much higher for MicNo than both nano & micron ZnO. It has proven to have a much higher absorbance of rays within the UV wavelength, especially in the UVA range, than nano ZnO. MicNo also offers a higher sun protection factor (SPF), which is the measure of protection from UVB rays, when used at the same concentration as nano ZnO.

MicNo has exhibited a higher visible light transparency than the current commercial nano ZnO particles. It is also able to cover a larger surface area per % mass; with its novel hexagonal shape able to cover approximately 70% more surface area than the same amount of nano ZnO, assuming no agglomeration takes place. A low level of uncontrolled agglomeration is another advantage of MicNo over the commercially available versions of ZnO which exhibit uncontrolled agglomeration both in micron & nano forms. With the right formulation using MicNo it is possible to create an SPF 50 product with broad spectrum & transparent protection.
The novel & patented MicNo particle technology creates ZnO particles in the micron size range that do not easily penetrate the skin, unlike the smaller nano particles. This means that MicNo has a much lower toxicity level than nano ZnO, similar to micron ZnO.

Research has shown MicNo to be biocompatible & safe, with it presenting much less cytotoxicity, genotoxicity & phototoxicity when compared to commercial nano ZnO. MicNo also exhibited less phytotoxicity since, unlike nano ZnO, it does not accumulate in plant roots. This biocompatibility of MicNo makes it a much kinder sunscreen for the environment as it causes less pollution & damage to aquatic & plant life.

MicNo also has excellent antimicrobial properties, exhibiting broad spectrum antibacterial activity against a range of microorganisms & a number of fungi. This makes it easier to prepare formulations with less or no preservatives, a feature which is particularly appealing to manufactures due to this recent trend in cosmetic product formulations.

Considering the recent market trend for broad spectrum coverage, MicNo offers very high protection to high energy visible light & blue light. While SPF & protection against UV rays is the current main priority of sun protection products, high energy visible light is also known to cause aging effects so an additive which offers extra protection, can only be considered advantageous.

ATTRIBUTE MICRON NANO MicNo®
UV Protection per mass Low High Very High
Transparency (unless they are aglomerated) No Very High High
Surface cover per mass Low High Very High
High energy visible light / Blue light protection High Low High
Level of toxicity Low Very High Low
Uncontrolled agglomeration High Very High Low
Level of phototoxicity Low Very High Low
Broad spectrum antibacterial activity Yes Yes Yes

Table comparing the main attributes of micron, nano & MicNo® particles.

MicNo® is a novel & innovative particle that exhibits the safety of micron & the power of nano.
With its unique designed structure, the MicNo® particle can harness the all benefits & overcome the problems associated with the conventional micron & nano ZnO forms currently used in sunscreens to allow formulators to develop sunscreen products that protect both environment & human health.
For further information please contact,

Gürol Özhan Demirel
T: +90 222 320 36 63
M: +90 554 778 91 45
E: GurolDemirel@EnteknoMaterials.com