High-throughput testing – ensuring safe cosmetics with cutting-edge robotics

When seasoning our meals with salt or putting on perfume, we keep a fine balance between too much and too little. The same balance is also important for preservatives in cosmetics, which should only be added at the lowest possible limits.

AMICA, a cutting-edge robot in Clariant’s German innovation labs, is a powerful new tool for determining these limits. It tests preservatives at an unprecedented level of speed and efficiency – enhancing the safety of skin care users, sunbathers, and toddlers.

A fast new “friend” in the lab

In preservation chemistry, the fine line between too much and too little is called minimum inhibitory concentration, or MIC. It is the lowest concentration at which a preservative prevents the growth of germs like bacteria and fungi.

MIC testing is mainly done by hand, however, now there is a much faster and more efficient way: with AMICA. The name stands for Automatized Minimum Inhibitory Concentration Assay. And the robot it belongs to is part of a microbiology team at the Clariant Innovation Center (CIC) in Frankfurt am Main, Germany.

Petra Schaal, who manages the development of new preservation solutions for Clariant, explains that AMICA is also the female word for “friend” in Latin.

“We chose it because having this robot is really like having a helpful new friend around. A very fast friend, I might add.” – Petra Schaal, Manager Preservation

Eight tireless tips behind glass

At the CIC, the robot works tirelessly in an upstairs room of the center’s labs. It consists of a ceiling-high gray box with a large window and a small city of equipment inside. With one sliding arm, AMICA mounts pipette tips, draws up liquids, fills them into microplates. With the other, it transfers the plates to built-in incubators and reading tools.

“AMICA essentially is a state-of-the-art high-throughput system that allows us to very quickly test how effectively antimicrobial compounds do their job,” Petra says. “Different concentrations of the compounds are mixed with germs and growth medium. Then the samples are incubated and regularly checked over a certain span of days.”

AMICA measures a range of parameters to see how happily the germs are multiplying in the plates’ wells. In each run, serial dilutions of up to 32 antimicrobials can be tested against up to 8 different organisms. The well that contains the lowest level of an antimicrobial to still prevent growth defines this compound’s MIC.

Using AMICA for “safer” safety

Clariant’s cutting-edge robot makes MIC testing substantially faster than is possible with conventional methods. In a recent university study, a similar setup also boasted 100% accuracy. That’s a level hard to reach even for the most conscientious lab assistant.

“We use AMICA to speed up our collaboration with Clariant’s personal care customers,” Petra says. “Each formulation has its own preservation needs. And quickly finding the right balance can be crucial for being the first to bring a new product to market.”

To aid cosmetic formulators in their work, Clariant provides an online database they can browse with a preservatives finder. The featured products include one of Clariant’s specialties: multifunctional boosters. These synergistic compounds enhance the effects of traditional preservatives – which can significantly lower their use.

“Boosters like our Velsan^™ SC make cosmetics less dependent on conventional preservatives and their potential drawbacks,” explains Petra. “They provide safer safety, so to speak, while also being largely biobased and bringing all kinds of other benefits. AMICA is a great tool for testing the efficacy of such innovations.”

Robotic precision, human creativity

Inside AMICA’s incubators, a tiny drop of multifunctional booster may team up with an alcohol or organic acid against typical foes such as Staphylococcus aureus and Candida albicans. Like a microbial sports reporter, the robot regularly takes snapshots of these heated matches.

The result of this so-called kinetic analysis is a series of graphs and figures. In the case of Velsan SC, they would show that the booster can more than double the effects of alcohols, and greatly broaden those of organic acids. When combined with natural plant extracts, it can even eliminate the need for traditional preservatives altogether.

So, with a friend like AMICA around, can Petra and her colleagues just sit back and fold their hands? Not really. Preparing the high-throughput runs requires planning and care. And ultimately, it still takes human experience, intuition, and creativity to guide and give meaning to the robot’s work.

“AMICA is more like a synergistic booster,” Petra says with a smile. “It helps us work faster for our customers, and also to more quickly try out new ideas, boosting our capacity for innovation.”

These ideas are developed in close collaboration with the CIC’s personal care experts. They include formulations such as synergistically boosted skin gels, suntan lotions, and baby creams. Helping to make cosmetics safer, more sustainable, and more in tune with evolving regulations, AMICA thus ultimately is a new friend for all of us.

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