Biocompatible Two-Dimensional Titanium Nanosheets for Multimodal Imaging-Guided Cancer Theranostics

Abstract

Photothermal therapy (PTT) based on two-dimensional (2D) nanomaterials has shown significant potential in cancer treatment. However, developing 2D nanomaterial-based photothermal agents with good biocompatibility and high photothermal conversion efficiency (PTCE) remains a key challenge. Titanium and its alloys have been widely employed as biomedical materials based on their biocompatibility. In this work, the elemental Ti based plasmonic photothermal therapy (Ti-PPTT) is demonstrated. Using the liquid-phase exfoliation (LPE), it was shown that metallic Ti can be fabricated into the 2D nanosheets (NSs), similar to exfoliating other layered 2D materials.Furthermore, the 2D Ti NSs exhibited good biocompatibility, high extinction coefficient of 20.8 Lg −1 cm −1 and high PTCE of 73.4%, owing to localized surface plasmon resonances (LSPR); which is significantly higher than other photothermal agents, including Au (21%), MoS 2 (24.4%), BP (28.4%) and Ti 3 C 2 MXene (30.6%).Interestingly, the Ti NSs can be degraded into TiO 2 in water-based solution and made themselves hydrophilic in the meantime. Consequently, 2D Ti-PPTT exhibited a notable therapeutic effect in a human hepatocellular carcinoma model without side effects. Our study could pave a new avenue for PTT using metal Ti and arouse a wide interest in the potential efficient PTT for other elemental transition metals owing to their LSPR.

Multifunctional black phosphorus/MoS2 van der Waals heterojunction

“…As we know, MoS 2 is an n-type semiconductor with reasonably high electron mobility and a bandgap ranging from 1.2 to 1.8 eV [14,15]. Few-layer BP has a narrow bandgap of ~0.3 eV, and it is a p-type semiconductor with high carrier mobility [7,[16][17][18][19][20][21][22][23][24]. Therefore, the integration of two materials to form a heterojunction can enable a large bandgap offset achieving good rectifying characteristics.…”

Novel two-dimensional monoelemental and ternary materials: growth, physics and application

“…Simultaneously, improved CVD, PVD, PLD and magnetron sputtering methods to prepare large-area 2D materials have been developed well. So far, the common methods used to synthesize 2D monoelemental and ternary materials are LPE or micromechanical exfoliation, yielding a very small size ranging from hundreds of nanometers to tens of micrometers and bringing a number of foreign atoms or by-products, whereas for biomedical application, a large quantity of biocompatible 2D materials with small size are suitable and efficient, such as novel titanium nanosheets prepared by the LPE method [199]. Thus, the discussed 2D monoelemental materials in this paper can be extended to be used in drug therapy and carriers such as GSH functionalized Te nanosheets [144].…”

Solution-processed two-dimensional materials for ultrafast fiber lasers (invited)

“…For example, in medicine, stable pulses operating at ~2 μm are required for surgery due to the water absorption at this wavelength [4,5], while pulses operating in the ~1-1.5 μm range are required for imaging, to minimize photodamage and maximize penetration depth [6]. Owing to their high performance, design flexibility, and low maintenance costs [7,8], fiber lasers have been particularly successful in applications such as medicine [9,10], telecommunication [11], and sensing [12]. Optical pulses, as required by most applications, are generated by a mode-locking or Q-switching technique [13,14], where an intensitydependent saturable absorber (SA) is typically used [15].…”