Injecting cosmetic drugs into the skin to gain a younger look involves invasive, painful procedures. Prof. Dror Fixler and a team of BIU researchers use innovative chemical and optical techniques to demonstrate that inserting nano-particles of these materials enhances their efficacy while eliminating the pain.
The fountain of everlasting youth
“We would all like to stay young forever. The skincare industry - generating over $100B annually - promises us the moon. However, nature has its own rules, which is why promises of eternal beauty can be deceiving”, cautions Prof. Fixler, a researcher in the Faculty of Engineering and a member of BINA.
“Our skin is a remarkably sturdy organ, designed as a protective shield, which enables us to survive even in hot desert conditions, and in sub-zero climates”, exclaimed Fixler. “To penetrate this barrier, skin-rejuvenation solutions use laser therapy, whereby substances are injected in the skin through tiny holes – a procedure performed by a licensed physician. An example is Hyaluronic acid (HA) - a natural substance in the skin with powerful anti-aging properties, which cosmetic companies have tried to synthesize. However, reducing HA polymers in order to insert them in the skin, is costly and time-consuming”, he explained.
Hunting for nano-submarines
In a research project sponsored by the Israeli cosmeceutical firm Hava Zingboim Ltd., a team of researchers working alongside Prof. Fixler, including Prof. Rachel Lubart (Emeritus), and Ph.D. student Inbar Yariv, devised a simple and fast fabrication technique for synthesizing nano-scale HA molecules of less than 100nm in size. Similarly, other organic materials were converted to nano form, including Vitamin B12 - known for its anti-oxidative properties; methylene blue - another oxidizing agent for treating toenail fungus; and even Penicillin.
To fabricate these nanoparticles (NPs), the team utilized sonochemistry - the same technology used in submarines. “By applying ultrasonic radiation to an aqueous solution of the material, sound waves prompt a chemical reaction, causing bubbles to form and expand. The molecules naturally forge a shell surrounding the bubble, which implodes when reaching an unstable size. This causes a massive build-up of energy, creating NPs that contain many small molecules”, Fixler explained. “The fabrication of these nano organic drugs - unchanged in their chemical structure and small enough to penetrate the skin - gives new life to the compounds, and is likely to impact medicine and pharmaceuticals dramatically”.
Mysteries of the deep
After synthesizing NPs, the team still had to validate their nano-form efficacy. “One of the advantages of nanoscale materials is their larger surface areas as compared to bulk form,” stated Fixler. “Interestingly, the NPs exhibited enhanced antibacterial and antioxidant activity, compared to the same amount of bulk material - both in nano-Vitamin B12 and in nano-penicillin - which killed more bacteria than regular penicillin”.
In order to demonstrate that these nano-materials actually reach the targeted depth within the skin, a simulated tissue with low optical conductivity was used. “We developed an optical technique, utilizing the Gerchberg-Saxton algorithm – which is used typically for reconstructing optical images”, explained Fixler. “The technique is based on two physical properties that affect light propagating through tissue: scattering - the change in light phase; and absorption - the decrease in the light’s intensity”.
NPs of Methylene Blue - a material with high scattering and absorption coefficients - were inserted into the simulated tissue. The intensity of the light was measured in several predetermined locations. By retrieving the phase of the observed scattered light, the team was able to calculate the reduced scattering coefficient, and compute the penetration depth of the NPs. Wherever the phase remained unchanged, the indication was that the NPs had not reached that depth.
This innovative, non-invasive technique enables accurate detection of NPs, marking the first step in tracking their physical penetration depths. According to Fixler, it could take at least 6-12 months until this technology is adopted by the cosmetics industry. Nevertheless, it holds a vast, untapped potential for research and commercial uses. For example, “One such possible application is by sending out a small ray of light from a UAV (unmanned aerial vehicle) for remote detection of cargo content on freight carriers,” Prof. Fixler said.
Originally published in Institute for Nanotechnology and Advanced Materials' April 2017 newsletter