Journal of Nanomedicine & Nanotechnology

Plasmonic Nanomaterials for Sensing and Detection of Pathogens

Juniper Hollis^* Department of Nanotechnology, Georgia Institute of Technology, USA
^*Correspondence: Juniper Hollis, Department of Nanotechnology, Georgia Institute of Technology, USA, Email:

Received: 02-Nov-2024, Manuscript No. jnmnt-24-28302; Editor assigned: 05-Nov-2024, Pre QC No. jnmnt-24-28302 (PQ); Reviewed: 20-Nov-2024, QC No. jnmnt-24-28302; Revised: 25-Nov-2024, Manuscript No. jnmnt-24-28302 (R); Published: 30-Nov-2024, DOI: 10.35248/2157-7439.24.15.765

INTRODUCTION

The detection of pathogens in clinical, environmental, and food safety applications is essential for preventing the spread of infectious diseases. Traditional pathogen detection methods, such as culture-based techniques and polymerase chain reaction (PCR), often require time-consuming procedures and specialized equipment. In contrast, plasmonic nanomaterials offer a rapid, sensitive, and cost-effective alternative for pathogen sensing. Plasmonic nanomaterials, such as gold nanoparticles (AuNPs), silver nanoparticles (AgNPs), and nanorods, can undergo a phenomenon known as surface plasmon resonance (SPR) or localized surface plasmon resonance (LSPR) when exposed to light. These phenomena result in the amplification of light scattering and absorption, which can be used to detect the presence of specific pathogens through shifts in the optical signals. The ability of plasmonic nanomaterials to provide highly sensitive and specific detection, combined with their ease of functionalization with biomolecules such as antibodies, peptides, and DNA, has made them ideal candidates for pathogen detection in a variety of settings. This article aims to provide a comprehensive overview of plasmonic nanomaterials in pathogen sensing, focusing on their applications, mechanisms, and challenges in the development of next-generation diagnostic tools [1].

TYPES OF PLASMONIC NANOMATERIALS FOR PATHOGEN SENSING

Gold Nanoparticles (AuNPs)

Gold nanoparticles (AuNPs) are among the most widely studied plasmonic nanomaterials for biosensing applications due to their unique optical properties, ease of functionalization, and biocompatibility. When excited by light, AuNPs undergo LSPR, leading to enhanced scattering and absorption. The optical properties of AuNPs are highly sensitive to changes in the local environment, such as the binding of pathogens or biomolecules [2]. The strong absorption and scattering features of AuNPs can be measured through colorimetric or spectroscopic techniques, making them ideal for pathogen detection in real-time. AuNPs can be functionalized with various recognition molecules, such as antibodies, aptamers, or nucleic acids, to selectively bind to specific pathogens. This functionalization enables AuNPs to serve as highly selective and sensitive sensors for detecting pathogens in complex biological samples, such as blood, saliva, or urine. Additionally, the aggregation of AuNPs upon pathogen binding leads to a visible color change, which can be detected by the naked eye or using a spectrophotometer [3].

Silver Nanoparticles (AgNPs)

Silver nanoparticles (AgNPs) are another type of plasmonic nanomaterial that exhibits strong LSPR properties. Similar to AuNPs, AgNPs can be functionalized with specific biomolecules to selectively capture pathogens. AgNPs are known for their antimicrobial properties, which can enhance pathogen detection by inhibiting the growth of bacteria during the detection process. AgNPs also offer enhanced optical properties, such as sharper plasmonic peaks and higher scattering efficiencies compared to AuNPs, making them suitable for low-concentration pathogen detection.

AgNPs are frequently used in colorimetric assays for pathogen detection, where the aggregation or dispersion of nanoparticles results in a shift in the color of the solution. This allows for simple, rapid, and inexpensive detection methods that can be performed without the need for complex instrumentation [4].

Gold Nanorods (AuNRs)

Gold nanorods (AuNRs) are an anisotropic form of gold nanoparticles that exhibit distinct plasmonic properties compared to spherical AuNPs. AuNRs possess two main plasmonic resonances: one in the longitudinal direction and one in the transversal direction. The longitudinal plasmon resonance can be tuned across a wide range of wavelengths by adjusting the aspect ratio of the nanorods. This tunability enables the detection of pathogens at various wavelengths and enhances the sensitivity of the sensor. AuNRs are particularly useful in surface-enhanced Raman scattering (SERS) and SPR-based sensing due to their unique optical characteristics. The application of AuNRs in pathogen detection involves the functionalization of their surface with biomolecules that specifically recognize pathogens. Upon binding to the target pathogen, the plasmonic properties of the nanorods change, resulting in detectable shifts in scattering or absorbance that are correlated with the presence of the pathogen [5].

Plasmonic Nanoshells

Plasmonic nanoshells are another class of nanomaterials that consist of a dielectric core surrounded by a thin metal shell, typically made of gold or silver. Nanoshells exhibit tunable plasmonic resonances that can be optimized for pathogen detection by adjusting the thickness of the metal shell and the size of the core. The unique optical properties of plasmonic nanoshells allow them to be used in a variety of sensing applications, including SPR, LSPR, and SERS. The sensitivity of plasmonic nanoshells to environmental changes, such as the binding of pathogens, enables their use in label-free detection systems. Plasmonic nanoshells can be functionalized with biomolecules that specifically recognize pathogens, allowing for selective pathogen detection. Their strong light scattering properties make them ideal candidates for detecting pathogens in dilute samples or in complex environments, such as blood or urine.

MECHANISMS OF PLASMONIC SENSING

Plasmonic sensing relies on the interaction between light and the electrons in the metal nanoparticle, which results in the collective oscillation of electrons known as surface plasmon resonance (SPR) or localized surface plasmon resonance (LSPR). These interactions lead to significant changes in the optical properties of the nanoparticles, which can be used to detect the presence of pathogens [6].

Surface Plasmon Resonance (SPR): SPR occurs when the frequency of incident light matches the natural frequency of oscillation of the free electrons on the surface of the nanoparticle. This resonance causes a significant shift in the angle or wavelength of light reflected from the surface. By monitoring these shifts, SPR sensors can detect changes in the local refractive index, which occurs when pathogens or other biomolecules bind to the nanoparticle surface.

Localized Surface Plasmon Resonance (LSPR): LSPR occurs when light interacts with metallic nanoparticles at the nanoscale, causing the conduction electrons in the nanoparticle to oscillate in resonance with the incident light. This phenomenon results in enhanced scattering and absorption of light, which can be measured to detect changes in the local environment, such as the binding of pathogens.

Surface-Enhanced Raman Scattering (SERS): SERS is a technique that involves the enhancement of Raman signals when molecules are adsorbed onto plasmonic nanomaterials. The strong electromagnetic fields generated by the plasmonic resonance of the nanoparticles lead to a significant increase in the Raman scattering cross-section, allowing for sensitive detection of pathogens even at low concentrations [7].

APPLICATIONS IN PATHOGEN DETECTION

Plasmonic nanomaterials are being used in a wide range of applications for pathogen detection, including

Clinical Diagnostics: Plasmonic sensors can be used to detect bacterial and viral pathogens in clinical samples, such as blood, urine, or saliva. The ability to rapidly identify pathogens and their specific strains is crucial for timely treatment and preventing the spread of infectious diseases.

Environmental Monitoring: Plasmonic nanomaterials can be employed for detecting environmental pathogens, such as waterborne bacteria or viruses in drinking water or recreational waters. Rapid pathogen detection in environmental samples is critical for ensuring public safety and monitoring contamination.

Food Safety: Plasmonic sensors can be used to monitor food products for the presence of harmful pathogens, such as E. coli, Salmonella, or Listeria, thereby improving food safety and preventing foodborne illness outbreaks [8].

CHALLENGES AND LIMITATIONS

Despite the promising applications of plasmonic nanomaterials in pathogen detection, several challenges remain:

Specificity: Achieving high specificity for detecting particular pathogens can be challenging, especially in complex biological samples. Cross-reactivity with other biomolecules or environmental factors may lead to false positives or negatives.

Sensitivity: While plasmonic nanomaterials are highly sensitive, detecting low concentrations of pathogens in real-world samples often requires careful optimization of the nanoparticle size, surface chemistry, and functionalization methods to achieve the necessary sensitivity [9].

Reproducibility and Scalability: The production of plasmonic nanomaterials with consistent optical properties is crucial for reliable pathogen detection. Achieving reproducibility in large-scale manufacturing and ensuring that sensors work effectively across different environments are ongoing challenges.

FUTURE DIRECTIONS

Future research in plasmonic nanomaterials for pathogen sensing is focused on enhancing the sensitivity, specificity, and real-time monitoring capabilities of plasmonic sensors. Advances in nanostructuring, functionalization techniques, and integrating plasmonic sensors with portable devices hold the potential to improve pathogen detection technologies. Additionally, combining plasmonic sensing with other detection techniques, such as PCR or electrochemical sensors, may lead to the development of more comprehensive diagnostic platforms for infectious diseases [10].

CONCLUSION

Plasmonic nanomaterials represent a promising approach for the rapid, sensitive, and selective detection of pathogens in clinical, environmental, and food safety applications. The unique optical properties of these materials enable highly efficient pathogen sensing, making them ideal for point-of-care diagnostics and real-time monitoring. Despite challenges related to specificity, sensitivity, and scalability, ongoing advancements in nanoparticle design and functionalization are expected to pave the way for the development of next-generation pathogen detection technologies.

REFERENCES

Indexed at, Google Scholar, Crossref

Google Scholar, Crossref

Google Scholar, Crossref

Google Scholar, Crossref

Indexed at, Google Scholar, Crossref

Google Scholar, Crossref

Indexed at, Google Scholar, Crossref

Indexed at, Google Scholar, Crossref

Google Scholar, Crossref

Indexed at, Google Scholar, Crossref

1. Jones LW, Anderson T. Exercise Oncology: Historical Perspective and Future Directions. Cold Spring Harb Perspect Med. 2023;13(6): a037038.
2. Lee JH, Wilson W. Virus-Mimicking Phytosomes for Drug Delivery in Cancer. Pharmaceutics. 2020; 12(3): 229.
3. White KA, Parker N. Expanding the Scope of Enzyme Specificity for Genome Engineering. J Am Chem Soc. 2021; 143(45):18445-18450.
4. Garcia JR, Wilson W. RNA Delivery and Therapeutics for Oncology. Trends Pharmacol Sci. 2021; 42(11): 905-915.
5. Kamaly N, Yameen B, Wu J. Degradable Controlled-Release Polymers and Polymeric Nanoparticles: Mechanisms of Controlling Drug Release. Chemical Reviews. 2016; 116(4): 2602-2663.
6. Lee K, Anderson R. Nanoparticles in Biology and Medicine: Small Structures with Big Potential. Adv healthc mater. 2022; 11(19): 2100713.
7. Harrison OJ, Smith SJ, Sperandio M. Detection and Discrimination of Intact and Cleaved E-Cadherin Fragment Release from Cell Surfaces: Implications for Understanding the Role of E-Cadherin in Angiogenesis and Cancer Progression. J Proteome Res. 2023; 22(1): 683-693.
8. Hoshyar N, Gray S, Han H. The effect of nanoparticle size on in vivo pharmacokinetics and cellular interaction. Nanoscale. 2016; 8(13): 6731-6747.
9. Zhang S, Bellinger A, Genshaft A. A blood–brain barrier–penetrating gut-microbe-derived molecule that enhances amyloid beta deposition and cognitive impairment in a mouse model. Science Advances. 2021; 7(23): eabf1773.
10. Tong R, Chiang HH, Kohane DS. Photoswitchable nanoparticles for in vivo cancer chemotherapy. Proc Natl Acad Sci. 2020; 110(46): 19048-19053.