Activating Layered Metal Oxide Nanomaterials via Structural Engineering as Biodegradable Nanoagents for Photothermal Cancer Therapy

Abstract

Layered metal oxides including MoO3 and WO3 have been widely explored for biological applications owing to their excellent biocompatibility, low toxicity, and easy preparation. However, they normally exhibit weak or negligible near‐infrared (NIR) absorption and thus are inefficient for photo‐induced biomedical applications. Herein, the structural engineering of layered MoO3 and WO3 nanostructures is first reported to activate their NIR‐II absorption for efficient photothermal cancer therapy in the NIR‐II window. White‐colored micrometre‐long MoO3 nanobelts are transformed into blue‐colored short, thin, defective, interlayer gap‐expanded MoO3−x nanobelts with a strong NIR‐II absorption via the simple lithium treatment. The blue MoO3−x nanobelts exhibit a large extinction coefficient of 18.2 L g−1 cm−1 and high photothermal conversion efficiency of 46.9% at 1064 nm. After surface modification, the MoO3−x nanobelts can be used as a robust nanoagent for photoacoustic imaging‐guided photothermal therapy to achieve efficient cancer cell ablation and tumor eradication under irradiation by a 1064 nm laser. Importantly, the biodegradable MoO3−x nanobelts can be rapidly degraded and excreted from body. The study highlights that the structural engineering of layered metal oxides is a powerful strategy to tune their properties and thus boost their performances in given applications.

Emerging Trends in Nanomaterials for Antibacterial Applications

“… 196 , 197 A set of transition metals and their oxide and sulfide forms can advantageously absorb more laser energy compared to inorganic PTAs. 198 , 199 For instance, in our previous investigation of the photothermal effects on E. coli of gold nanorods (AuNRs) and gold nanobipyramids (AuNBPs), 100 µg/mL of AuNRs and 25 µg/mL of AuNBPs were used to kill E. coli with an efficiency of 100% after 808-nm laser illumination for 7 min. 200 The principle of antibacterial PTT is illustrated in Figure 17 .…”

Recent Progress on Two-Dimensional Materials

“…Such a unique structural feature of 2D materials endows them with various unconventional physical, chemical, optical, electronic and magnetic properties as compared to their bulk, zero-dimensional (0D) and one-dimensional (1D) counterparts 2 . Owing to their unusual properties, 2D materials have been proven to be one of the most promising candidates for numerous potential applications like electronics [11][12][13][14] , optoelectronics [15][16][17][18][19][20] , catalysis [21][22][23][24][25][26] , energy storage [27][28][29][30][31][32][33][34] , solar cells [35][36][37][38] , biomedicine [39][40][41][42][43][44][45] , sensors [46][47][48][49] , environments [50][51][52][53][54] , etc. Driven by their unusual properties and promising applications, a large number of novel 2D materials beyond graphene, such as transition metal dichalcogenides (TM...…”

Cancer nanotechnology: current status and perspectives

“…Although photothermal agents (PTAs) have shown promising results in clinical studies, rapid degradation of PTA limits the photothermal stability required for efficacious treatment yet those with high photothermal stability degrade slowly thus have greater safety concerns [366,367]. Currently, there are few PTAs with high photothermal stability and rapid degradation.…”