Nanogel frontier: Unveiling the power of natural extracts and hyaluronic acid for skin wellness

17 Oct 2023 --- Recent research is highlighting how nanogels, tiny powerhouses that absorb a range of active substances and gradually release them in targeted areas, are used in dermatology and cosmetics. Separate research harnessed the potential of Dendrobium anosmum (D. anosmum), a species of orchid, to synthesize zinc oxide (ZnO) nanoparticles via green methods to combat acne.

Green nanotechnology, which focuses on environmentally sustainable applications, is evolving rapidly, according to researchers. Plants used in Traditional Chinese Medicine, like Dendrobium spp. orchid types have long been studied for their therapeutic potential.

D. anosmum, with its array of secondary metabolites, was proven to be a candidate for green synthesis of metallic nanoparticles, especially ZnO nanoparticles.

Acne-fighting nanoparticles
Acne vulgaris is a common skin disorder resulting from high sebum production, bacterial colonization, hormonal changes and genotypic influences. 

Its treatment often involves antibiotics, but their overuse poses antimicrobial resistance risks, flag the authors. ZnO nanoparticles are gaining attention due to their low toxicity, UV-absorption properties and biodegradability, making them potential alternatives to antibiotics, share the researchers.

Thus, the scientists incorporated ZnO into topical nanogels for their antibacterial properties against Cutibacterium acne (C. acne) and Staphylococcus aureus (S. aureus), acne-causing bacteria.

Compounds supporting the synthesis process
The researchers found that D. anosmum leaf extract contained secondary metabolites like carotenoids, coumarin, flavonoids, phenols, saponin, steroids, tannins and terpenoids. D. anosmum leaf extract contained secondary metabolites like carotenoids, coumarin, flavonoids, phenols, saponin, steroids, tannins and terpenoids.

These compounds, mainly phenols and flavonoids, serve as reducing and capping agents in the ZnO nanoparticle biosynthesis process. These findings indicate the presence of compounds essential for ZnO nanoparticle synthesis. 

ZnO nanoparticles were synthesized using chemogenic and biogenic methods. Biogenically synthesized ZnO nanoparticles had a higher yield of 69.75% compared to 15.99% in chemogenic synthesis. 

Furthermore, the green-synthesized ZnO nanoparticles showed a smaller particle size and an absorption peak at 352 nm, suggesting their potential for enhanced antibacterial activity, according to the study.

Formulating with polymers
The scientists formulated topical nanogels using two polymers, Carbopol 940 and HPMC, with ZnO nanoparticles. 

Despite the white color of ZnO nanoparticles, the appearance of the nanogels differed. The Carbopol 940 gel remained transparent, with visible white nanoparticles, while HPMC exhibited a cream color with a uniform texture. 

These variations in appearance are attributed to differences in viscosity and spreadability, according to the authors.

Anti-acne efficacy
D. anosmum was shown to be a promising source for green-synthesized ZnO nanoparticles. Nanogels are tiny powerhouses that absorb a range of active substances and gradually release them in targeted areas.

These nanoparticles, when incorporated into nanogels, exhibit antibacterial activity against C. acne and S. aureus, highlighting their potential for developing eco-friendly anti-acne products, according to the researchers. 

The results demonstrated that nanogels containing biogenically synthesized ZnO nanoparticles (from D. anosmum) were the most effective against these acne-causing bacteria, surpassing both chemogenic ZnO nanoparticles and pure ZnO nanoparticles. 

This indicates the potential of green-synthesized ZnO nanoparticles in developing novel anti-acne agents, according to the authors.

Allure of hyaluronic acid
Another research paper reviewed hyaluronic acid nanogels as potential carriers of actives for dermatological and cosmetic applications.

Nanogels share many traits with traditional hydrogels, such as impressive absorption and drug-loading capabilities. However, they add a twist, coming in nanoparticle form that boosts mass transfer processes and allows for systemic administration.

The pivotal role of hyaluronic acid in skin health and aging makes nanogels especially appealing. 

Hyaluronic acid, a natural component of the skin’s extracellular matrix, is essential for skin hydration. Its decline within the skin’s tissues over time correlates with a reduction in elasticity, the emergence of wrinkles and other visible signs of aging.

Nanogels grounded in hyaluronic acid offer an opportunity to amalgamate sustained drug release with the well-documented benefits of hyaluronic acid for skin health. 

These nanogels are tailor-made for dermatological and cosmetic applications, offering multiple roles by enhancing skin health, enabling effective drug delivery and promoting anti-aging benefits.Chemical structure of hyaluronic acid (Image credit: Hyaluronic acid nanogel review).

Untapped potential of hyaluronic acid-based nanogels
Despite the mounting interest in hyaluronic acid-based nanogels for dermatological and cosmetic applications in recent years, the researchers find that the field remains relatively unexplored compared to the extensive research dedicated to hyaluronic acid and nanogels designed for systemic drug delivery.

They notice a growing trend of nanocarriers in a dermatological or cosmetic context, since the past two to three years.

“Minor scrapes, burn wounds, aging and skin diseases require the use of different types of therapeutics to avoid worsening of the condition and prevent the spread of infections,” write the authors.

“Drug delivery by topical route is challenging due to the multi-layered structure of the skin. In particular, the stratum corneum of the epidermis, due to its composition in proteins and lipids…For these reasons, the formulation of nanocarriers is of great interest.”

The authors stress that nanogels offer opportunities for cosmetic formulators beyond traditional drug delivery applications, which can inspire innovative solutions for dermatology and cosmetics.

“Not only therapeutics but also pigments and inorganic compounds can be encapsulated in nanogels, extending the considerations made above to cosmetic applications,” they add.

By Venya Patel