Thomas Jany and Rafael Ricon
Rafael Ricon is a high school junior at Dougherty Valley High School in California who aims to pursue a career in medical research. His passions are track and field, playing the trumpet, and recently, following the development of nanomedicine.
Thomas Jany is currently in 11th grade at the International School of Basel in Switzerland. Driven by a passion for the sciences, he will most likely opt for a career in engineering, be it genetic, medical, or materials. Outside of the classroom Thomas skis, swims, plays tennis and golf.
Introduction to Nanotechnology
Nanotechnology is an exciting field that uses infinitesimal substances to heal grievous wounds, exponentially enhance computers, and treat unconquerable conditions from paralysis to cancer [2, 22, 27]. Nanomaterials may be immeasurably tiny, yet their promise is all but minor, as they have contributed to almost all industries. They enhance vehicle efficiency, purify deadly water, and may treat cancer, autoimmune diseases, and even regenerate limbs [2, 26, 35]. As such, interest in nanotechnology has surged, and rigorous scientific testing is underway.
Nanotechnology encompasses technology with at least one dimension between 1-100 nanometers (a billionth of a metre) . To scale, a phage (bacteria-targeting virus) is 70 nm wide; a human hair can be 100,000 nanometers wide; and a nanometer is only as long as three gold atoms [6, 32]. This technology has been discussed worldwide for decades. The field is so new that there still is no standard classification of nanomaterials. One proposed method by Dr. Jagannath Padmanabhan classifies nanomaterials as nanoparticles, nanoporous scaffolds, nanopatterned surfaces, nanofibers, and carbon nanotubes. Nanoparticles are tiny capsules used for drug delivery. Nanoporous scaffolds are mesh-like structures used to build blood vessels and regulate drug release. Nanopatterned surfaces are surfaces with tiny features, such as rods, ridges, or grooves, which affect cell shape and function. Nanofibers, consisting of long strings of porous material, deliver drugs or aid in wound healing. Carbon nanotubes are used to aid tissue engineering, act as scaffolds, and deliver drugs. In addition, they are the only electrically conductive nanomaterial types .
Healing occurs in four phases. In hemostasis, blood thickens to form a clot [19, 31]. This occurs with inflammation: white blood cells divide and migrate, engulfing any foreign particles [19, 31]. Reactive Oxygen Species (ROS) are produced to recruit inflammatory cells and kill infections. However, excess ROS can prevent proper healing [19, 31]. Proliferation is next: cells divide and move to the wound; some partake in angiogenesis (capillary generation), and some form granulation tissue, such as a temporary scar or scab to form structure on which the skin may begin to close the wound [19, 31]. Finally, the skin undergoes remodeling: skin or scar tissue made of connecting cells and collagen replaces the granulation tissue. Although not identical to actual skin, it still effectively functions as a barrier [19, 31].
However, nature is far from perfect: healing is a long, tedious process that requires many enzymes, proteins, and special cells. Without them, or under unfavorable conditions, wounds will not heal. Without protection, wounds become infected. Wounded soldiers and hospital patients are especially vulnerable, making wound protection an imperative goal. Additionally, if one lacks specific proteins and healing factors, chronic wounds can develop and never heal, which often results in amputation or death. This often happens in the elderly and diabetic, whose bodies cannot produce these factors.
Before nanotechnology, many different treatments were utilized for wound healing. In order to accelerate the healing process, people ingested zinc sulphate , applied growth factors on the skin surface , or used honey on wounds , among other methods. As for chronic wounds, electrodes would sometimes be used to stimulate healing via electric currents , or used other conventional methods (as one would expect, it was often ineffective). These treatments, although sometimes effective, are flawed and not nearly as powerful as desired (treating wounds with pulsing electricity, for example, yielded only 22% healing per week for chronic wounds, which is a very slow rate of healing) .
Nanotechnology holds the potential to improve wound healing treatments. A multitude of treatments can accelerate healing via increased skin and angiogenesis. Many nanomaterials effectively kill bacteria and provide valuable protection. Still more treatments can induce healing in chronic wounds, even if these patients naturally lack the vital factors needed to heal. As these treatments further develop, there may one day be definitive, effective treatments for each obstacle in the healing process.
Healing Acceleration and Bactericidal Properties
Many nanomaterial treatments have shown promise to accelerate healing. One promising treatment is a nano-sized silk mat loaded with EGF (epidermal growth factor, which induces keratin production and accelerates healing), which was shown to close wounds by 84% after only twenty-four hours as opposed to the control, which only achieved a maximum of 4.4% closure . After forty-eight hours, the wound had almost completely healed; the control had not even reached 10% closure . Another treatment with potential is a wound dressing based on a silver and graphene hydrogel, which protected against bacteria (being able to wipe out an entire colony of E. Coli bacteria in vitro) while also accelerating healing by 23% to 43% (based on the concentration of silver in the hydrogel: the higher concentration was more effective) . Yet another is a peptide-based scaffold loaded with EGF, which induced three times more skin regeneration than the controls after only 24 hours . After 48 hours, the scaffold had induced up to 64% wound closure, while the control only achieved 9% . Each method has been proven to have minimal adverse effects, and are only a few of the many cutting-edge treatments that may find success. These methods and hundreds more, may shape the future of wound healing.
While there are many potential treatments in development, specific substances stand out for their versatility and promise. Nanoscale nitric oxide (NO) is among them. As an effective bactericide, NO is vital to wound healing. Its absence can cause complications and impair healing . NO has been shown to protect against Staphylococcus aureus (S. aureus, a leading cause of infections in homes and hospitals), Acinetobacter baumannii (a dangerous drug resistant bacteria that infects wounds sustained while fighting in the Middle East, as well as the leading cause of hospital-acquired infections), and a variety of other pathogens [25, 39], NO can be topically applied, for example, as nanoparticles contained in a silica hydrogel, to protect wounds and accelerate healing.  NO nanoparticles ensure that the vascular system limits blood flow and protects against pathogens during hemostasis and inflammation . During proliferation, NO stimulates angiogenesis and aids collagen deposition during remodeling . This application can reduce the scab of an S. aureus infected wound by 31.25% . Its uses in the nanoscale and its versatility in many wound types have earned nitric-oxide a spotlight in nanomaterial wound healing.
Nanoscale silver is also a promising solution. Silver is both bactericidal and aids in wound healing acceleration. Silver destroys bacteria via lysis (destroying the cell membrane by imbalancing electron concentrations via reacting with proteins), pairing with the DNA bases (thereby inhibiting mitosis), and/or ribosome inhibition (hindering protein synthesis), and is effective against S. aureus and Escherichia coli (E. coli) [12, 7] Wound healing can be induced by a dressing with silver crystals of 10-15nm . In pigs, a near normal epidermis was present seventy-two hours after wounding . Nanosilver can accelerate wound healing by regulating collagen deposition during remodeling. It also aligns these collagen fibres (resulting in faster cell movement, which accelerates healing)  . If introduced in earlier phases, such as during hemostasis, there are no adverse effects . If topically applied, such as via nanoscaffold, and coated with keratin, the pores allow for optimum conditions for wound healing: a moist, breathable environment and protection from the outside . In another study, topically applied silver nanoparticles accelerated complete healing nine days faster than an untreated wound while also reducing scarring and inducing hair growth . While silver does have many advantages, too much silver can lead to brain, kidney, lung, liver, and eye damage, cardiac abnormalities, and anemia [30, 33]. Silver’s powerful antibacterial and healing properties make it invaluable in wound treatments.
Nanoscale chitosan (made by adding alkaline solutions to ground crustacean and shellfish shells) is yet another powerful healing agent . It accelerates tissue regeneration, stimulates hemostasis, and has antibacterial properties (proposed to be a reaction between the opposite charges of chitosan and bacteria, or an inhibition of microbial DNA), effective against E. coli and S. aureus [1, 14, 17]. It also vastly accelerates wound healing in vivo. As it is hydrophilic, it also keeps wounds moist, one of the requirements for successful wound healing . It is biodegradable, and is a safe, easily disposable treatment.  Combined with melatonin in nanoparticles, it closed lacerations up to 56% over twenty-four hours . Its effectiveness and versatility in various scaffolds and nanoparticle delivery systems make chitosan a powerful contender in nanomaterial wound healing. All mentioned treatments have minimal adverse effects, and are but a fraction of the cutting-edge treatments currently being explored for wound healing.
Healing chronic wounds is also an imperative goal.There were 171 million diabetics in 2000, yet this number is projected to rocket to 366 million in 2030, and 25% of these patients will develop chronic wounds . The elderly live under the same risk; and as more of the population is able to survive to an older age, so too does the number of people at risk of developing chronic wounds. A fibrin-based scaffold loaded with growth factors is one hopeful treatment for chronic wounds . It induced more granulation tissue growth (creating new skin and blood vessels) complete skin regeneration, and induces less scarring in diabetic mice . Another treatment has found similar success: gold nanoparticles, used in conjunction with anti-oxidants, effectively raised the levels of an important EGF that is decreased by diabetes and significantly decreased the wound sizes of diabetic mice . Another promising treatment is topically applied lipid nanoparticles loaded with EGF. The treatment significantly increased collagen production and greatly decreased wound size compared to an intra-lesional control treatment . These treatments are only a few of the multitudes of treatments that may one day find definitive success aiding many who are and will be afflicted by chronic wounds.
Obstacles and Conclusion
Nanotechnology may have promise, but it must first overcome several obstacles to find success. Primarily, the Foreign Body Reaction (FBR) renders all implants useless. Collagen is formed around the implant, preventing it from functioning. Adverse effects, such as toxicity, must also be accounted for. As nanotechnology is a recent advancement, there are still many unprecedented risks to address. However, for each obstacle that looms ahead, there are thousands of potential treatments for wound healing. The impact that nanomaterials may have on all areas of life, from transportation, to energy, to revolutionary medicine outline a healthier, safer, and brighter future for mankind.
Much thanks to our T.As, Chia-Ying and Danielle. Without their guidance on reading and understanding primary literature, as well as their constant feedback and support during the writing process and the making of our presentation, these three weeks would have been far more stressful and less of an exciting learning experience, both in nanobiomaterials and in understanding scientific literature. Thank you for your invaluable help, constructive criticism, and being amazing counselors and T.As.
Much of this final culmination of our efforts throughout these few weeks is owed to Jagan Padmanabhan. His teaching method was engaging and, at times, entertaining, and his philosophy on the nature of the scientific method, the divide between laymen and scientists and the duty to bridge it, and his emphasis on a practical, skeptical mindset without elitism or dismissiveness have greatly impacted how many, not all of us, view science. His time, intellect, and wisdom were amazing gifts throughout the program.
- Ahmed, S., & Ikram, S. (2016). Chitosan Based Scaffolds and Their Applications in Wound Healing. Achievements in the Life Sciences,10(1), 27-37. doi:10.1016/j.als.2016.04.001
- Benefits and Applications. (n.d.). Retrieved July 06, 2017, from https://www.nano.gov/you/nanotechnology-benefits
- Berthet, M., Gauthier, Y., Lacroix, C., Verrier, B., & Monge, C. (2017). Nanoparticle-Based Dressing: The Future of Wound Treatment? Trends in Biotechnology. doi:10.1016/j.tibtech.2017.05.005
- Blažević, F., Milekić, T., Romić, M. D., Juretić, M., Pepić, I., Filipović-Grčić, J., . . . Hafner, A. (2016). Nanoparticle-mediated interplay of chitosan and melatonin for improved wound epithelialisation. Carbohydrate Polymers, 146, 445-454. doi:10.1016/j.carbpol.2016.03.074
- Blecher, K., Martinez, L. R., Tuckman-Vernon, C., Nacharaju, P., Schairer, D., Chouake, J., . . . Friedman, A. J. (2012). Nitric oxide-releasing nanoparticles accelerate wound healing in NOD-SCID mice. Nanomedicine: Nanotechnology, Biology and Medicine,8(8), 1364-1371. doi:10.1016/j.nano.2012.02.014
- Cell Size and Scale. (n.d.). Retrieved July 07, 2017, from http://learn.genetics.utah.edu/content/cells/scale/
- Chaloupka, K., Malam, Y., & Seifalian, A. M. (2010). Nanosilver as a new generation of nanoproduct in biomedical applications. Trends in Biotechnology,28(11), 580-588. doi:10.1016/j.tibtech.2010.07.006
- Chen, S., Chen, H., Yao, Y., Hung, C., Tu, C., & Liang, Y. (2012). Topical treatment with antioxidants and Au nanoparticles promote healing of diabetic wound through receptor for advanced glycation end-products. European Journal of Pharmaceutical Sciences, 47(5), 875-883. doi:10.1016/j.ejps.2012.08.018
- Efem, S. E. (1988). Clinical observations on the wound healing properties of honey. British Journal of Surgery, 75(7), 679-681. doi:10.1002/bjs.1800750718
- Enhancement of wound healing by topical treatment with epidermal growth factor. (1990). American Journal of Otolaryngology, 11(2), 140. doi:10.1016/0196-0709(90)90015-n
- Fan, Z., Liu, B., Wang, J., Zhang, S., Lin, Q., Gong, P., . . . Yang, S. (2014). A Novel Wound Dressing Based on Ag/Graphene Polymer Hydrogel: Effectively Kill Bacteria and Accelerate Wound Healing. Advanced Functional Materials, 24(25), 3933-3943. doi:10.1002/adfm.201304202
- Feng, Q. L., Wu, J., Chen, G. Q., Cui, F. Z., Kim, T. N., & Kim, J. O. (2000). A mechanistic study of the antibacterial effect of silver ions on Escherichia coli and Staphylococcus aureus. Journal of Biomedical Materials Research, 52(4), 662-668. doi:10.1002/1097-4636(20001215)52:4<662::aid-jbm10>3.0.co;2-3
- Gainza, G., Pastor, M., Aguirre, J. J., Villullas, S., Pedraz, J. L., Hernandez, R. M., & Igartua, M. (2014). A novel strategy for the treatment of chronic wounds based on the topical administration of rhEGF-loaded lipid nanoparticles: In vitro bioactivity and in vivo effectiveness in healing-impaired db/db mice. Journal of Controlled Release, 185, 51-61. doi:10.1016/j.jconrel.2014.04.032
- Goy, R. C., Morais, S. T., & Assis, O. B. (2016). Evaluation of the antimicrobial activity of chitosan and its quaternized derivative on E. coli and S. aureus growth. Revista Brasileira de Farmacognosia, 26(1), 122-127. doi:10.1016/j.bjp.2015.09.010
- Kim, G., & Rosso, J. D. (2010). Antimicrobial and Healing Efficacy of Sustained Release Nitric Oxide Nanoparticles Against Staphylococcus Aureus Skin Infection. Yearbook of Dermatology and Dermatologic Surgery, 2010, 174-175. doi:10.1016/s0093-3619(09)79607-8
- Kloth, L. C., & Feedar, J. A. (1988). Acceleration of Wound Healing with High Voltage, Monophasic, Pulsed Current. Physical Therapy, 68(4), 503-508. doi:10.1093/ptj/68.4.503
- Kong, M., Chen, X. G., Xing, K., & Park, H. J. (2010). Antimicrobial properties of chitosan and mode of action: A state of the art review. International Journal of Food Microbiology, 144(1), 51-63. doi:10.1016/j.ijfoodmicro.2010.09.012
- Losi, P., Briganti, E., Errico, C., Lisella, A., Sanguinetti, E., Chiellini, F., & Soldani, G. (2013). Fibrin-based scaffold incorporating VEGF- and bFGF-loaded nanoparticles stimulates wound healing in diabetic mice. Acta Biomaterialia, 9(8), 7814-7821. doi:10.1016/j.actbio.2013.04.019
- Mancini, M. C. (2017, May 24). How wounds heal. Retrieved July 12, 2017, from https://medlineplus.gov/ency/patientinstructions/000741.htm
- Martinez, L. R., Han, G., Chacko, M., Mihu, M. R., Jacobson, M., Gialanella, P., . . . Friedman, J. M. (2009). Antimicrobial and Healing Efficacy of Sustained Release Nitric Oxide Nanoparticles Against Staphylococcus Aureus Skin Infection. Journal of Investigative Dermatology, 129(10), 2463-2469. doi:10.1038/jid.2009.95
- Mihu, M. R., Sandkovsky, U., Han, G., Friedman, J. M., Nosanchuk, J. D., & Martinez, L. R. (2010). The use of nitric oxide releasing nanoparticles as a treatment against Acinetobacter baumannii wound infections. Virulence, 1(2), 62-67. doi:10.4161/viru.1.2.10038
- Nano in Healthcare. (n.d.). Retrieved July 07, 2017, from http://ec.europa.eu/research/industrial_technologies/nano-in-healthcare_en.html
- Nayak, K. K., & Gupta, P. (2017). Study of the keratin-based therapeutic dermal patches for the delivery of bioactive molecules for wound treatment. Materials Science and Engineering: C,77, 1088-1097. doi:10.1016/j.msec.2017.04.042
- Padmanabhan, J., Dr., & Kyriakides, T. R. (2014, November 25). Nanomaterials, Inflammation, and Tissue Engineering. Retrieved July 07, 2017, from http://wires.wiley.com/WileyCDA/WiresArticle/wisId-WNAN1320.html
- Pelgrift, R. Y., & Friedman, A. J. (2013). Nanotechnology as a therapeutic tool to combat microbial resistance. Advanced Drug Delivery Reviews,65(13-14), 1803-1815. doi:10.1016/j.addr.2013.07.011
- Pories, W., Henzel, J., Rob, C., & Strain, W. (1967). Acceleration Of Wound Healing In Man With Zinc Sulphate Given By Mouth. The Lancet, 289(7482), 121-124. doi:10.1016/s0140-6736(67)91031-8
- Saini, R., Saini, S., & Sharma, S. (2010, April). Nanotechnology: The Future Medicine. Retrieved July 07, 2017, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2890134/
- Schneider, A., Wang, X., Kaplan, D., Garlick, J., & Egles, C. (2009). Biofunctionalized electrospun silk mats as a topical bioactive dressing for accelerated wound healing. Acta Biomaterialia, 5(7), 2570-2578. doi:10.1016/j.actbio.2008.12.013
- Schneider, A., Garlick, J. A., & Egles, C. (2008). Self-Assembling Peptide Nanofiber Scaffolds Accelerate Wound Healing. PLoS ONE, 3(1). doi:10.1371/journal.pone.0001410
- Silver [Ag, 47]. (2015). Trace Elements in Abiotic and Biotic Environments,301-306. doi:10.1201/b18198-45
- Simon, P. E. (2017, June 20). Skin Wound Healing. Retrieved July 10, 2017, from http://emedicine.medscape.com/article/884594-overview
- Size of the Nanoscale. (n.d.). Retrieved July 07, 2017, from https://www.nano.gov/nanotech-101/what/nano-size
- Tian, J., Wong, K., Ho, C., Lok, C., Yu, W., Che, C., . . . Tam, P. (2007). Topical Delivery of Silver Nanoparticles Promotes Wound Healing. ChemMedChem, 2(1), 129-136. doi:10.1002/cmdc.200600171
- Vellayappan, M., Jaganathan, S. K., & Manikandan, A. (2016). Nanomaterials as a game changer in the management and treatment of diabetic foot ulcers. RSC Adv., 6(115), 114859-114878. doi:10.1039/c6ra24590k
- Water Treatment Solutions. (n.d.). Retrieved July 11, 2017, from http://www.lenntech.com/periodic/elements/ag.htm
- Wong, K. K., Tian, J., Ho, C., Lok, C., Che, C., Chiu, J., & Tam, P. K. (2006). Topical delivery of silver nanoparticles reduces systemic inflammation of burn and promotes wound healing. Nanomedicine: Nanotechnology, Biology and Medicine, 2(4), 306. doi:10.1016/j.nano.2006.10.117
- Wright, J. B., Lam, K., Buret, A. G., Olson, M. E., & Burrell, R. E. (2002). Early healing events in a porcine model of contaminated wounds: effects of nanocrystalline silver on matrix metalloproteinases, cell apoptosis, and healing. Wound Repair and Regeneration,10(3), 141-151. doi:10.1046/j.1524-475x.2002.10308.x
- Yang, X., Yang, J., Wang, L., Ran, B., Jia, Y., Zhang, L., . . . Jiang, X. (2017). Pharmaceutical Intermediate-Modified Gold Nanoparticles: Against Multidrug-Resistant Bacteria and Wound-Healing Application via an Electrospun Scaffold. ACS Nano,11(6), 5737-5745. doi:10.1021/acsnano.7b01240
- Yoo, J., Nurhasni, H., Cao, J., Choi, M., Kim, I., Lee, B. L., & Jung, Y. (2015). Nitric oxide-releasing poly(lactic-co-glycolic acid)-polyethylenimine nanoparticles for prolonged nitric oxide release, antibacterial efficacy, and in vivo wound healing activity. International Journal of Nanomedicine,3065. doi:10.2147/ijn.s82199
- Younes, I., & Rinaudo, M. (2015). Chitin and Chitosan Preparation from Marine Sources. Structure, Properties and Applications. Marine Drugs, 13(3), 1133-1174. doi:10.3390/md13031133