These days, “nano” is everywhere we look – from cosmetics to clothing to food, and everywhere in between. Concerns have been raised over the safety and environmental impact of nanomaterials in products we use every day. At BNN, we collaborate with members and project partners to consider the safety and sustainability of nanotechnologies (as well as other new technologies) from the beginning of the innovation process. With this series of posts, we intend to shed light on just a few of the many application areas of nanoparticles around us – some of which are already on the market and some are in development. We hope you enjoy and share!
So, how small is one nanometer? “If each person on Earth was the size of a nanometre, everyone on the planet would fit into one Hot Wheels matchbox car.” (Source: https://www.science.org.au/curious/nanoscience)
Zinc oxide (ZnO) – / Titanium dioxide (TiO2)
Zinc oxide and titanium dioxide are well-known ingredients in sunblock due to their ability to absorb UV light, but the pasty white color they leave on your skin is annoying. In the nanoscale, however, particles of zinc oxide and titanium dioxide scatter visible light – thus making the sunblock itself transparent rather than white, while offering UV protection.
To kill bacteria, nanosilver is used as an antimicrobial agent in clothing, such as socks and activewear. However, its toxicity to organisms could impact environment negatively and yield human health concerns.
Titanium Dioxide (TiO2) nanoparticles
To purify water, titanium dioxide enhances the effect of UV light to destroy dangerous microorganisms and convert pollutants to less harmful products. It is frequently used in waste water treatment plants.
Gold (Au) / Silver nitrate (Ag)
Nanoparticles were accidental ingredients in stained glass in the Middle Ages. By adding flecks of gold chloride to molten glass, the painters could create deep purples and reds, and by adding silver nitrate, the glass turned yellow, due to the changing light-reflecting properties of the nanoparticles.
Aluminum Oxide (Al2O3)
The crystal form of aluminum oxide at the nanoscale is softer than at larger sizes, so it polishes teeth to remove plaque but is less abrasive on the tooth enamel
When added to foams used in furniture upholstery, carbon nanofibers reduce flammability of furniture significantly compared to conventional flame retardants.
Gold nanoparticles (AuNPs)
Gold nanoparticles have attracted enormous scientific and technological interest due to their ease of synthesis, chemical stability, and unique optical properties. Variations in parameters such as size, shape, surface charge and coating material can lead to different results when determining gold nanoparticles’ interactions with biomolecules, cell lines and tissues. Gold nanoparticles (AuNPs) have emerged as popular materials for various biomedical applications, such as bioimaging, biosensors, cancer therapy, and drug delivery. In biomedical diagnostics, the best-known rapid test using AuNPs is the human chorionic gonadotropin pregnancy test. AuNPs are a powerful tool in point-of-care testing because of their flexibility, modifiability, and visibility.
In the DeDNAed project, for example, gold nanoparticles are used in biosensors with a variety of applications, such as testing for COVID and food contaminants.
Effective drug delivery for disease treatment
Among lipid-based nanovesicles, liposomes are one of the most promising carriers for nanomedical applications. Liposomes have shown excellent potential as pharmaceutical carriers due to their biocompatibility and biodegradability, and their versatility in terms of size, composition, surface properties and their ability to entrap soluble and non-soluble drug compounds. Liposomes are spherical nanovesicles composed of amphiphilic molecules that self-assemble in one or several closed lipid bilayers.
There are approximately 15 liposomal-based nanomedicines approved for clinical used and more than a hundred in various stages of clinical trials representing more than 50% of clinical trials involving nanoparticles. Most widely explored areas for liposomes development are cancer, fungal and viral infections and vaccine developments. However, intense research on liposomal applications for other diseases such as paediatric illnesses, children’s anticancer therapy and RareDiseases (lysosomal storage disorder (LSD) therapy) still remain a challenge.
An urgent need for early detection and diagnosis of diseases continuously pushes the advancements of imaging modalities and contrast agents. Current challenges remain for fast and detailed imaging of tissue microstructures and lesion characterization that could be achieved via development of nontoxic contrast agents with longer circulation time. Nanoparticles can offer this possibility. Quantum dots (QD) for example are active sensor elements in high-resolution cellular imaging. QD are semiconductor crystals with a typical core-shell structure with sizes between 1-10 nanometers. They yield a very bright light which changes color according to size. However, safety properties of quantum dots should first be addressed as well as efficacy and theragnostic capabilities before using QD nanoparticles as medical imaging agents.
Hydroxyapatite coating is used in medical devices such as implants for orthopaedics that support bone ingrowth and osteointegration, such as screws for orthopedic surgeries. Hydroxyapatite coatings are known to be both biocompatible – meaning well tolerated by our bodies – and to enhance osteointegration of implants – meaning they form strong and stable bonds with bone tissue. This is due to their chemical and crystal resemblance to the mineral component of bone adjacent to the implant.
Nanosilica & Calcium Phosphate (CaP) nanoparticles
In dentistry, nanoparticles are mainly used as fillers in nanocomposites. The main advantages of nanocomposites over other composite materials include a high surface/volume ratio that allows small filler size and reduced inter-particle separation, enhanced mechanical properties, high ductility without strength loss, scratch resistance and improved thermal and optical properties.
Research is focused on studying the properties of dental resin composites with different average sizes and their mechanical properties such as with Nanosilica particles or their contribution to long-term inhibition of tooth decay such as with CaP nanoparticles, among others.
Gelatin & Chitosan nanoparticles
Nanotechnology provides many opportunities for the food industry – from nano food additives to intelligent packaging with sensors to detect when food has gone bad, to antibacterial packaging leading to longer shelf-lives. Additional benefits include better nutrient delivery using nanoencapsulation known as “functional foods”, improving flavors, texture and colors of food. A number of food ingredients needed to be encapsulated before incorporation in food systems for maintaining their properties, such as liposoluble vitamins, bioactive lipids like omega-3 fatty acids and others. Several techniques are used for nanoencapsulation such as emulsification, nanoprecipitation or freeze-drying. Nevertheless, the safety of novel food products must also be addressed.