Capping gold nanoparticles with albumin to improve their biomedical properties

Abstract

Nanotechnology is an emerging field which has created great opportunities either through the creation of new materials or by improving the properties of existing ones. Nanoscale materials with a wide range of applications in areas ranging from engineering to biomedicine have been produced. Gold nanoparticles (AuNPs) have emerged as a therapeutic agent, and are useful for imaging, drug delivery, and photodynamic and photothermal therapy. AuNPs have the advantage of ease of functionalization with therapeutic agents through covalent and ionic binding. Combining AuNPs and other materials can result in nanoplatforms, which can be useful for biomedical applications. Biomaterials such as biomolecules, polymers and proteins can improve the therapeutic properties of nanoparticles, such as their biocompatibility, biodistribution, stability and half-life. Serum albumin is a versatile, non-toxic, stable, and biodegradable protein, in which structural domains and functional groups allow the binding and capping of inorganic nanoparticles. AuNPs coated with albumin have improved properties such as greater compatibility, bioavailability, longer circulation times, lower toxicity, and selective bioaccumulation. In the current article, we review the features of albumin, as well as its interaction with AuNPs, focusing on its biomedical applications.

Keywords: albumin; drug delivery; photothermal therapy; theranostics.

Figure 1

Different shapes of gold nanoparticles used in biomedical applications. Reprinted from Journal of Experimental & Clinical Medicine, 6, Ajnai G, Chiu A, Kan T, Cheng C-C, Tsai T-H, Chang J, Trends of gold nanoparticle-based drug delivery system in cancer therapy, pages 172-178, Copyright (2014) with permission from Elsevier.

Figure 2

LSPR on gold nanoparticles, generated by the interaction between the conduction electrons on gold surface and the incident light on (A) non-anisotropic spherical AuNP, (B) longitudinal and (C) transversal anisotropic rod-shape AuNP.

Figure 3

UV-Vis absorption spectrum AUNSs (black line), AUNRs (red line) and the oscillation modes on AuNPs.

Figure 4

Photothermal effect on gold nanoparticles. After irradiation AuNPs absorbs light, which leads to an electronic transition of the surface electrons from a ground state (S0) to an excited state (S1). The energy is released in the environment of the nanostructure as local heat. Republished with permission of Future Medicine Ltd, from Gold nanoparticles for photothermally controlled drug release, Guerrero AR, Hassan N, Escobar CA, Albericio F, Kogan MJ, Araya E, 9, 2014; permission conveyed through Copyright Clearance Center, Inc.

Figure 5

Crystal structure of BSA. Reprinted from Elsevier, 52(3-4) , Majorek KA, Porebski PJ, Dayal A, et al. Structural and immunologic characterization of bovine, horse, and rabbit serum albumins, 174-182, Copyright 2012, with permission from Elsevier.

Figure 6

Albumin uptake in tumor interstitial mediated by transcytosis with GP60 and subsequent binding to SPARC in the extracellular tumor matrix. Reprinted from Journal of Controlled Release, 157, Elsadek B, Kratz F, Impact of albumin on drug delivery - New applications on the horizon, Pages 4-28, Copyright (2012), with permission from Elsevier.

Figure 7

Nanoparticles surface modification with albumin. Copyright © 2016. John Wiley and Sons. Reproduced from Chen Q, Liu Z. Albumin carriers for cancer theranostics: a conventionalplatform with new promise. Adv Mater. 2016;28:10557–10566.

Figure 8

Absorption of SA on AuNP surface can be achieved by: (A) passive absorption of SA constituent functional groups attached to gold surface; (B) adsorption of activated SA modified with functional groups improving the surface binding properties; (C) growing of AuNPs embedded on SA structure after in situ synthesis.

Figure 9

Methods fo SA encapsulation of AuNPs. (A) desolvation method using an organic solvent and a crosslinker agent, (B) emulsification in oil phase, (C) thermal gelation by heat promoted unfolding of SA.

Figure 10

Fluorescence microscopy images of the cytotoxic effects on 4T1 breast cancer cells when treated with free AuNRs, AuNR-HSAPs or PAC-AuNR-HSAPs. (White scale bar denotes 100 μm). Reprinted with permission from Peralta DV, Heidari Z, Dash S, Tarr MA. Hybrid paclitaxel and 1030 gold nanorod-loaded human serum albumin nanoparticles for simultaneous chemotherapeutic and photothermal therapy on 4T1 breast cancer cells. ACS Appl Mater Interfaces. 2015;7:7101–7111. Copyright 2015 American Chemical Society.

Figure 11

Capability of NR@SA nanoplatform for PA imaging. (A) 2 × 2 mm area of projected C-scan PA images of nontreated and NR@SA treated tramp C1 tumor cells. (B) in vivo photoacoustic imaging from tumor-bearing mice during and after local delivery of NR@SA. Reprinted with permission from Chiu HT, Chen CH, Li ML, et al. Bioprosthesis of core-shell gold nanorod/serum albumin nanoimitation: a half-native and half-artificial nanohybrid for cancer theranostics. Chem Mater. 2018;30:729–747. Copyright (2018) American Chemical Society.

Figure 12

(A) In vivo targeted cancer fluorescence images of Hela tumor-bearing mice exposed to the laser (488 nm, 425 mW cm2, 25 min) after injection of the DOX/RGD-BSA@AuNCs system. (B) The images of tumor excised from mice after injection of PBS solution or DOX/RGD-BSA@AuNCs solutions at 19 day. Reprinted with permission from Ding C, Xu Y, Zhao Y, Zhong H, Luo X. Fabrication of BSA@AuNC-based nanostructures for cell fluoresce imaging 1435 and target drug delivery. ACS Appl Mater Interfaces. 2018;10:8947-8954. Copyright (2018) American Chemical Society.