Science Behind NanoGold Nanoparticles in Biology and Medicine Recent Advances and Prospects
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3347577
Abstract
Very extensive research paper, 250 footnotes / sources.
Articles from Acta Naturae are provided here courtesy of National Research University Higher School of Economics
Functionalized gold nanoparticles with controlled geometrical and optical properties are the subject of intensive studies and biomedical applications, including genomics, biosensorics, immunoassays, clinical chemistry, laser phototherapy of cancer cells and tumors, the targeted delivery of drugs, DNA and antigens, optical bioimaging and the monitoring of cells and tissues with the use of state-of-the-art detection systems. This work will provide an overview of the recent advances and current challenges facing the biomedical application of gold nanoparticles of various sizes, shapes, and structures. The review is focused on the application of gold nanoparticle conjugates in biomedical diagnostics and analytics, photothermal and photodynamic therapies, as a carrier for delivering target molecules, and on the immunological and toxicological properties. Keeping in mind the huge volume and high speed of the data update rate, 2/3 of our reference list (certainly restricted to 250 Refs.) includes publications encompassing the past 5 years.
Paper dated 2011
Content
Gold is one of the first metals to have been discovered; the history of its study and application spans at least several thousand years. The first data on colloidal gold can be found in treatises by Chinese, Arabian, and Indian scientists, who managed to obtain colloidal gold as early as in the V–IV centuries BC. They utilized it for medicinal purposes (Chinese “golden solution” and Indian “liquid gold”), amongst other uses. In Europe during the Middle Ages, colloidal gold was studied and used in alchemist laboratories. Paracelsus wrote about the therapeutic properties of gold quintessence — “ quinta essentia auri, ” which he obtained via the reduction of gold chloride by vegetable extracts in alcohols or oils. He used the “potable gold” for the treatment of a number of mental diseases and syphilis. His contemporary, Giovanni Andrea, used “ aurum potabile ” as a therapy for patients with leprosy, plague, epilepsy, and diarrhea. In 1583, the alchemist David de Planis-Campy, who served as doctor to Louis XIII of France, recommended his “longevity elixir,” a colloidal solution of gold in water. The first book on colloidal gold preserved to our days was published in 1618 by the philosopher and doctor of medicine Francisco Antonii [1]. It contains data on how to obtain colloidal gold and its application in medicine, including practical advice.
Despite its centuries-old history, the “revolution in immunochemistry” associated with the use of gold nanoparticles (GNP) in biological studies occurred only in 1971, when the British researchers Faulk and Taylor [2] described a method of antibody conjugation with colloidal gold for direct electron microscopy visualization of the surface antigens of salmonellae. The study was initiated using biospecific markers – colloidal gold conjugated with immunoglobulins and other molecules – in different spheres of biology and medicine. Over the past 40 years, there have been many studies devoted to the application of functionalized nanoparticles – conjugates with recognizing biomacromolecules (antibodies, lectins, enzymes, aptamers, etc.) – in biochemistry, microbiology, immunology, cytology, plant physiology, morphology, etc.
The range of GNP use in modern medical and biology studies is extremely wide. In particular, it comprises genomics, biosensorics, immunoanalysis, clinical chemistry, detection and photothermolysis of microorganisms and cancer cells; the targeted delivery of drugs, DNA and antigens; optical bioimaging and the monitoring of cells and tissues using modern registration systems. It has been argued that gold nanoparticles could be used in almost all medical applications: diagnostics, therapy, prevention, and hygiene. A wealth of information on how to obtain and use colloidal gold in biology and medicine, as well as how it functions, can be found in books and reviews [3–8]. The broad range of applications for GNP is based on their unique physical and chemical properties. In particular, the optical properties of GNP are determined by their plasmon resonance, which is associated with the collective excitation of conduction electrons and localized in the broad region, from the visible to the infrared (IR) region, depending on the particle size, shape, and structure [9].
Taking into account the large volume of data published and the high speed at which they are updated, our review aimed to generalize the results obtained over the past several years in the most promising directions in the use of GNP in modern medical and biological studies.
Gold nanoparticles (AuNPs) have garnered significant attention in biology and medicine due to their unique physical and chemical properties, making them suitable for various biomedical applications.
Unique Properties of Gold Nanoparticles
AuNPs exhibit distinctive optical properties, such as localized surface plasmon resonance (LSPR), which can be tuned by adjusting their size and shape. This tunability allows for enhanced imaging and therapeutic capabilities. Additionally, their high surface area-to-volume ratio facilitates the conjugation of multiple biomolecules, enabling targeted delivery and improved biocompatibility.
Biomedical Applications
- Diagnostics and Imaging: AuNPs are employed in various imaging techniques, including electron microscopy and surface-enhanced Raman spectroscopy (SERS), to enhance contrast and enable the detection of specific biomolecules. Their ability to bind to specific antibodies or ligands allows for precise targeting of cellular structures or pathogens.
- Therapeutics:
- Drug Delivery: AuNPs serve as carriers for delivering therapeutic agents directly to diseased cells, minimizing systemic side effects. Their surfaces can be functionalized with drugs, peptides, or nucleic acids, facilitating targeted therapy.
- Photothermal Therapy (PTT): AuNPs can convert absorbed light into heat, enabling the selective destruction of cancer cells upon irradiation with near-infrared light. This method offers a minimally invasive treatment option with reduced damage to surrounding healthy tissues.
- Biosensing: AuNPs are integral components in the development of biosensors due to their ability to enhance signal detection. They are used in assays to detect various biomolecules, pathogens, or environmental toxins with high sensitivity and specificity.
Recent Advances
Recent research has focused on engineering AuNPs with specific shapes, such as nanorods or nanoshells, to optimize their optical properties for particular applications. Advancements in surface modification techniques have improved the stability and biocompatibility of AuNPs, enhancing their efficacy in clinical settings.
Challenges and Future Prospects
Despite their promising applications, challenges remain in the clinical translation of AuNPs. Concerns regarding long-term toxicity, biodistribution, and clearance from the body need to be thoroughly addressed. Future research is directed towards developing biodegradable AuNPs and exploring their interactions with biological systems to ensure safety and efficacy.
In conclusion, gold nanoparticles hold significant potential in revolutionizing diagnostics, therapeutics, and biosensing in medicine. Ongoing research and technological advancements continue to expand their applications, bringing us closer to realizing their full potential in clinical practice.