Gold nanoparticle-based colorimetric biosensors

Abstract

Gold nanoparticles (AuNPs) provide excellent platforms for the development of colorimetric biosensors as they can be easily functionalised, displaying different colours depending on their size, shape and state of aggregation. In the last decade, a variety of biosensors have been developed to exploit the extent of colour changes as nano-particles (NPs) either aggregate or disperse, in the presence of analytes. Of critical importance to the design of these methods is that the behaviour of the systems has to be reproducible and predictable. Much has been accomplished in understanding the interactions between a variety of substrates and AuNPs, and how these interactions can be harnessed as colorimetric reporters in biosensors. However, despite these developments, only a few biosensors have been used in practice for the detection of analytes in biological samples. The transition from proof of concept to market biosensors requires extensive long-term reliability and shelf life testing, and modification of protocols and design features to make them safe and easy to use by the population at large. Developments in the next decade will see the adoption of user friendly biosensors for point-of-care and medical diagnosis as innovations are brought to improve the analytical performances and usability of the current designs. This review discusses the mechanisms, strategies, recent advances and perspectives for the use of AuNPs as colorimetric biosensors.

Latest advances in combining gold nanomaterials with physical stimuli towards new responsive therapeutic and diagnostic strategies

“…Optical biosensors A typical AuNMs-based biosensor monitors the frequency shift in LSPR resonance [157]. Thus, the simplest implementation of LSPR sensing is the use of AuNMs as a functional component of colorimetric assays both in liquid (homophase methods) and solid (dot immunoassay and immunochromatography) phase [1].…”

“…Thus, the simplest implementation of LSPR sensing is the use of AuNMs as a functional component of colorimetric assays both in liquid (homophase methods) and solid (dot immunoassay and immunochromatography) phase [1]. In these assays, AuNMs are conjugated with a bioactive moiety capable of binding with high-affinity specific analytes present in a solution [157,158], such as biomolecules (e.g., proteins [159] or toxins [160]), small molecules (oligonucleotides [161]), ions (e.g., selenium [162]), or diseased cells (e.g., acute leukemia cells [163]). AuNMs-based optical sensors can also be used to detect specific antigens within the cellular compartments [164,165].…”

Electrospun Bacteria‐Gold Nanoparticle/Polymer Composite Mesofiber Nonwovens for Catalytic Application

“…Gold nanoparticles (AuNPs) have numerous applications in catalysis, biosensors, drug delivery, cancer therapy, antimicrobials, and cytogenotoxicity . Examples of catalysis include the oxidation of benzylalcohol to benzaldehyde, the conversion of cyclohexane to adipic acid, and the hydrolysis of dimethylphenylsilane to dimethylphenylsilanol or its alcoholysis to butoxydimethyl‐phenylsilane in poly(p‐xylylene (PPX) microtubes .…”

Density Modulation of Embedded Nanoparticles via Spatial, Temporal, and Chemical Control Elements

“…Controlled nanoparticle growth and distribution have found applications in various fields such as catalysis,optics, biological labeling and imaging, sensing, electronic and magnetic devices, and information storage . The proposed in situ reduction method is compatible with standard microfabrication techniques and, hence, provides easy access to construct devices that utilize the collective properties of nanoparticle distribution.…”

“…[10] Through an on-demand chemical reduction strategy, we formulated a universal composite photosensitive resin (CPR) with a post-fabrication in situ approach to control nanoparticle distribution density. External mixing of nanoparticles or salt solutions is avoided, and nanoparticles are synthesized on an on-demand basis "after" the complete fabrication process, with many control handles-spatial control within the medium (localized growth), thermal control (processing temperatures and temperature gradients), temporal control (time of the reduction reaction), concentration control, and chemical control (metal salt used).Controlled nanoparticle growth and distribution have found applications in various fields such as catalysis, [11] optics, [12] biological labeling and imaging, [13] sensing, [14] electronic [11] and magnetic devices, [12] and information storage. [15] The proposed in situ reduction method is compatible with standard microfabrication techniques and, hence, provides easy access to construct devices that utilize the collective properties of nanoparticle distribution.…”