A multifunctional nanoplatform based on black phosphorus quantum dots (BPQDs) was developed for cancer bioimaging and combined photothermal therapy (PTT) and photodynamic therapy (PDT). BPQDs were functionalized with PEG chains to achieve improved biocompatibility and physiological stability. The as-prepared nanoparticles exhibite prominent near-infrared (NIR) photothermal and red-light-triggered photodynamic properties. The combined therapeutic application of PEGylated BPQDs were then performed in vitro and in vivo. The results demonstrate that the combined phototherapy significantly promote the therapeutic efficacy of cancer treatment in comparison with PTT or PDT alone. BPQDs could also serve as the loading platform for fluorescent molecules, allowing reliable imaging of cancer cells. In addition, the low cytotoxicity and negligible side effects to main organs were observed in toxicity experiments. The theranostic characteristics of PEGylated BPQDs provide an uplifting potential for the future clinical applications.

Black phosphorus (BP), a new type of two-dimensional nanomaterial, has attracted crucial attention in recent years owing to its excellent properties and great potential in various chemical, physical, and biological fields. In this study, BP nanosheets loaded with Au nanoparticles (BP-Au NSs) are obtained by a one-step facile synthetic method. The Au nanostructures can not only enhance the photothermal efficiency of the nanocomposites, but also endow BP-Au NSs with the potential to act as effective surface-enhanced Raman scattering (SERS) substrates for Raman biodetection. Cancer photothermal therapy (PTT) has been carried out in vitro and in vivo using BP-Au NSs as nanoagents. Under irradiation by an 808 nm laser, BP-Au NSs are capable of producing sufficient hyperthermia to destroy cancer cells, and the transplanted tumors in most of the tumor-bearing mice disappeared; BP-Au NSs are more effective than bare BP nanosheets. The PTT effect can also be monitored by a Raman technique that benefits from the high SERS activity of the BP-Au NSs. The molecular fingerprint features of breast tumors before and after PTT treatment were clearly identified using SERS analysis. The theranostic applications of BP-Au NSs exhibit promising potential in biomedicine.

Ascribe to the unique two-dimensional planar nanostructure with exceptional physical and chemical properties, black phosphorous (BP) as the emerging inorganic two-dimensional nanomaterial with high biocompatibility and degradability has been becoming one of the most promising materials of great potentials in biomedicine. The exfoliated BP sheets possess ultra-high surface area available for valid bio-conjugation and molecular loading for chemotherapy. Utilizing the intrinsic near-infrared optical absorbance, BP-based photothermal therapy in vivo, photodynamic therapy and biomedical imaging has been realized, achieving unprecedented anti-tumor therapeutic efficacy in animal experiments. Additionally, the BP nanosheets can strongly react with oxygen and water, and finally degrade to non-toxic phosphate and phosphonate in the aqueous solution. This manuscript aimed to summarize the preliminary progresses on theranostic application of BP and its derivatives black phosphorus quantum dots (BPQDs), and discussed the prospects and the state-of-art unsolved critical issues of using BP-based material for theranostic applications.

In this work, we report a facile method using MoS2 quantum dots (QDs) as reducers to directly react with HAuCl4 for the synthesis of Au nanoparticle@MoS2 quantum dots (Au NP@MoS2 QDs) core@shell nanocomposites with an ultrathin shell of ca. 1 nm. The prepared Au NP@MoS2 QDs reveal high surface enhanced Raman scattering (SERS) performance regarding sensitivity as well as the satisfactory SERS reproducibility and stability. The limit of detection of the hybrids for crystal violet can reach 0.5 nM with a reasonable linear response range from 0.5 μM to 0.5 nM (R2 ≈ 0.974). Furthermore, the near-infrared SERS detection based on Au NP@MoS2 QDs in living cells is achieved with distinct Raman signals which are clearly assigned to the various cellular components. Meanwhile, the distinguishable SERS images are acquired from the 4T1 cells with the incubation of Au NP@MoS2 QDs. Consequently, the straightforward strategy of using Au NP@MoS2 QDs exhibits great potential as a superior SERS substrate for chemical and biological detection as well as bio-imaging.

The biological pH plays an important role in various cellular processes. In this work, a novel strategy is reported for biological pH sensing by using Raman spectroscopy and polyaniline nanoparticles (PANI NPs) as the pH-sensitive Raman probe. It is found that the Raman spectrum of PANI NPs is strongly dependent on the pH value. The intensities of Raman spectral bands at 1225 and 1454 cm increase obviously with pH value varying from 5.5 to 8.0, which covers the range of regular biological pH variation. The pH-dependent Raman performance of PANI NPs, as well as their robust Raman signals and sensitivities to pH, was well retained after the nanoparticles incorporated into living 4T1 breast adenocarcinoma cells. The data indicate that such PANI NPs can be used as an effective biological pH sensor. Most interestingly, the PANI spherical nanostructures can be acquired by a low-cost, metal-free, and one-pot oxidative polymerization, which gives them excellent biocompatibility for further biological applications.