Transferrin‐Coated Nanodiamond–Drug Conjugates for Milliwatt Photothermal Applications

Abstract

Fluorescent nanodiamonds (fNDs) are unique carbon-based nanomaterials due to their outstanding optical and magnetic properties. However, realization of the full potential of fNDs is often limited by their processability because fNDs aggregate strongly in both organic and aqueous solutions. Therefore, robust and potentially universal coating strategies are urgently needed to address these limitations. Derived from mussel foot proteins, the polymerization of l-3,4-dihydroxyphenylalanine (l-DOPA) provides important surface functional groups including amines, carboxylic acid, alcohols, and conjugated Michael acceptors. Herein, l-DOPA is polymerized on fNDs with a high control over the shell thickness. Photoluminescence and optically detected magnetic resonance studies reveal that the unique photophysical properties of fNDs are preserved after thin poly(l-DOPA) film coating. Subsequently, conjugation of transferrin, a heme protein that provides efficient receptor-specific cellular transport, improves the colloidal stability and cellular uptake of the poly(l-DOPA)-coated fNDs. The loading of FDA-approved indocyanine green as a photothermal agent yields an integrated biohybrid material exhibiting an amplified photothermal effect in cells at very low energy intake (≈90 mW cm −2 ).

Synthesis and Characterization of Bionanomaterials and Evaluation of Their Antioxidant, Antibacterial, and DNA Cleavage Activities

“…Moreover, the presence of shell thickness is very clearly seen in Figure 5B. [38] Besides, the surface morphology was greatly changed and became darker after coating with product 2, as shown in Figure 5C. In light of this information, we can say that the surface of product 1 has been successfully coated.…”

Fluorescent Nanodiamond–Nanogels for Nanoscale Sensing and Photodynamic Applications

“…[2] Due to their stable fluorescence, NDs with NV centers have been applied widely in bioimaging [3] as well as real-time reporters for drug delivery. [4][5][6] In addition, the emission wavelength of NDs is size-independent but tuneable from the visible to the near infrared region based on the color center (e.g., Si, Ge, etc.). [7] Furthermore, NDs containing negatively charged NV (NV -) centers can serve as single-spin sensors to detect critical physical parameters in a biological microenvironment, such as temperature, [8] magnetic fields, [9] electron spins, [10] and mechanical strain.…”

“…In the past, various different ND surface coating materials and strategies have been reported. The covalent attachment of functionalities such as a silica shell, [16] hyperbranched polyglycerols (HPG), [17] poly(L-DOPA), [5] and antibodies [18] has been explored as well as non-covalent adsorption of biomolecules or polymers like polyethyleneimine, [19] insulin, [20] and albumin-based copolymers. [4] Nevertheless, uncontrolled aggregation as well as precipitation still represents a challenge and each reported functionalization strategy has its benefits but also inherent limitations.…”

Fluorescent Nanodiamonds Encapsulated by Cowpea Chlorotic Mottle Virus (CCMV) Proteins for Intracellular 3D-Trajectory Analysis

“…SiV, GeV etc.). 2 Hence, NDs are widely used in bioimaging [3][4][5] , and drug delivery [6][7][8][9][10] . In addition, it has been proven that NDs can act as cellular biomarkers for long-term intracellular tracking.…”

“…23,24 Furthermore, surface coating is crucial to avoid foreign body interactions of the particles in vivo 25 and allows the nanoparticles to accumulate and remain at the target sites for a prolonged time period. Different surface coatings have been developed for this purpose, such as silica 26 , hyperbranched polyglycerol (HPG) 27 , poly(L-DOPA) 7 , insulin 28 , and human serum albumin (HSA), which was modified with polymers 6 , among others. In addition to synthetic common protein coatings, hybrid virus-like particles have recently gained attention due to their straightforward preparation, high biocompatibility, and unique properties and their application as drug delivery vehicles.…”