Construction of a Polypyrrole-Based Multifunctional Nanocomposite for Dual-Modal Imaging and Enhanced Synergistic Phototherapy against Cancer Cells

Remediation of Cr(VI)-contaminated soil by CS/PPy coupling with Microbacterium sp. YL3

In this research, a new material, chitosan/polypyrrole (CS/PPy), was synthesized and linked with the Cr(VI)-reducing bacterial strain YL3 to treat Cr(VI)-polluted soil. The findings demonstrated that the synergistic application of strain YL3 and CS/PPy achieved the greatest reduction (99.6 %). During the remediation process, CS/PPy served as a mass-storage and sustained release agent in the soil, which initially decreased the toxic effects of high concentrations of Cr(VI) on strain YL3, thereby enhancing the Cr(VI) reduction efficiency of strain YL3. These combined effects significantly mitigated Cr(VI) stress in the soil and restored enzyme activities. Furthermore, wheat growth in the treated soil also significantly improved. High-throughput sequencing of the microorganisms in the treated soil revealed that CS/PPy was not only effective at removing Cr(VI) but also at preserving the original microbial diversity of the soil. This suggests that the combined treatment using strain YL3 and CS/PPy could rehabilitate Cr(VI)-contaminated soil, positioning CS/PPy as a promising composite material for future bioremediation efforts in Cr(VI)-contaminated soils.

Nanotechnological strategies to increase the oxygen content of the tumor

Hypoxia is a negative prognostic indicator of solid tumors, which not only changes the survival state of tumors and increases their invasiveness but also remarkably reduces the sensitivity of tumors to treatments such as radiotherapy, chemotherapy and photodynamic therapy. Thus, developing therapeutic strategies to alleviate tumor hypoxia has recently been considered an extremely valuable target in oncology. In this review, nanotechnological strategies to elevate oxygen levels in tumor therapy in recent years are summarized, including (I) improving the hypoxic tumor microenvironment, (II) oxygen delivery to hypoxic tumors, and (III) oxygen generation in hypoxic tumors. Finally, the challenges and prospects of these nanotechnological strategies for alleviating tumor hypoxia are presented.

PpIX/IR-820 Dual-Modal Therapeutic Agents for Enhanced PDT/PTT Synergistic Therapy in Cervical Cancer

High treatment accuracy is the key to efficient cancer treatment. Photodynamic therapy (PDT) and photothermal therapy (PTT) are two kinds of popular, precise treatment methods. The combination of photodynamic and photothermal therapy (PDT/PTT) can greatly enhance the precise therapeutic efficacy. In this work, protoporphyrin IX (PpIX) was selected as the PDT agent (photosensitizer), and new indocyanine green (IR-820) was selected as the PTT agent. Further, the two kinds of theranostic agents were encapsulated by biological-membrane-compatible liposomes to form PpIX-IR-820@Lipo nanoparticles (NPs), a new kind of PDT/PTT agent. The PpIX-IR-820@Lipo NPs exhibited good water solubility, a spherical shape, and high fluorescence peak emission in the near-infrared spectral region (700-900 nm, NIR). The cellular toxicity of PpIX-IR-820@Lipo NPs for human cervical cancer cells (HeLa) and human cervical epithelial cells (H8) was detected by the CCK-8 method, and low cytotoxicity was observed for the PpIX-IR-820@Lipo NPs. Then, the excellent cellular uptake of PpIX-IR-820@Lipo NPs was confirmed by laser scanning confocal microscopy. Moreover, the PDT/PTT property of PpIX-IR-820@Lipo NPs was illustrated via 2',7'-dichlorofluorescin diacetate (DCFH-DA) and annexin V-fluorescein isothiocyanate (annexin V-FITC), as indicator probes. The PDT/PTT synergistic efficiency of PpIX-IR-820@Lipo NPs on HeLa cells was verified, exhibiting a high efficiency of 70.5%. Thus, the novel theranostic PpIX-IR-820@Lipo NPs can be used as a promising PDT/PTT synergistic theranostic nanoplatform in future cervical cancer treatment.

Mechanism and Application of Surface-Charged Ferrite Nanozyme-Based Biosensor toward Colorimetric Detection of l-Cysteine

Peroxidase-like nanozymes with robust catalytic capacity and detection specificity have been proposed as substitutes to natural peroxidases in biochemical sensing. However, the catalytic activity enhancement, detection mechanism, and application of nanozyme-based biosensors toward l-cysteine (l-Cys) detection still remain significant challenges. In this work, a doped ferrite nanozyme with well-defined structure and surface charges is fabricated by a two-step method of continuous flow coprecipitation and high-temperature annealing. The resulted ferrite nanozyme possesses an average size of 54.5 nm and a zeta-potential of 6.45 mV. A high-performance biosensor is manufactured based on the peroxidase-like catalytic feature of the doped ferrite. The ferrite nanozyme can oxidize the 3,3',5,5'-tetramethylbenzidine (TMB) with the assistance of H₂O₂ because of the instinctive capacity to decompose H₂O₂ into ·OH. The Michaelis-Menten constants (0.0911 mM for TMB, 0.140 mM for H₂O₂) of the ferrite nanozyme are significantly smaller than those of horseradish peroxidase. A reliable colorimetric method is established to selectively analyze l-Cys via a facile mixing-and-detecting methodology. The detection limit and linear range are 0.119 μM and 0.2-20 μM, respectively. Taking the merits of the ferrite nanozyme-based biosensors, the l-Cys level in the human serum can be qualitatively detected. It can be anticipated that the surface-charged ferrite nanozyme shows great application prospects in the fields of bioanalytical chemistry and point-of-care testing.

MoO3-x nanosheets-based platform for single NIR laser induced efficient PDT/PTT of cancer

Traditional combination therapy of photodynamic therapy (PDT) and photothermal therapy (PTT) is limited in the field of clinical cancer therapy due to activation by light with separate wavelengths, insufficient O₂ supply, antioxidant ability of glutathione (GSH) in tumor cell, and low penetration depth of light. Here, a multifunctional nanoplatform composed of MoO_3-x nanosheets, Ag nanocubes, and MnO₂ nanoparticles was developed to overcome these drawbacks. For this nanoplatform, hyperthermia and reactive oxygen species (ROS) were simultaneously generated under single 808 nm near-infrared (NIR) light irradiation. Once this nanoplatform accumulated in the tumor region, GSH was depleted by MnO₂ and intracellular H₂O₂ was catalyzed by MnO₂ to produce O₂ to relieve hypoxia. Ultrasound (US) imaging confirmed in-situ O₂ generation. Magnetic resonance (MR) imaging, photoacoustic (PA) imaging, and fluorescence imaging were used to monitor in vivo biodistribution of nanomaterials. This provides a paradigm to rationally design a single NIR laser induced multimodal imaging-guided efficient PDT/PTT cancer strategy.

Tumor-Targeting Multifunctional Nanoprobe for Enhanced Photothermal/Photodynamic Therapy of Liver Cancer

Numerous researchers have committed to the development of combined therapy strategies for tumors, since their use in the treatment of tumors has more ideal therapeutic outcomes. In the study, we designed and prepared gold nanostars with CD147 modified on the surface and then efficiently loaded a photosensitive drug IR820 to construct a multifunctional nanoprobe. Due to the protection effect of gold, the nanoprobe has oxygen/heat energy generation capability and can also efficiently deliver the loaded drugs inside the tumor cells. Moreover, the nanoprobe has excellent photothermal/photodynamic therapeutic outcomes. The observation by photoacoustic real-time imaging validated the outstanding tumor-targeting characteristics of our nanoprobe. Finally, in the in vivo treatment experiment, the nanoprobe achieved ideal tumor-suppressive effects after the photothermal/photodynamic therapy. In summary, the findings of this experiment are useful in the development of new combined tumor therapy strategies based on nanomaterials.

Synthesis of a Clay-Based Nanoagent for Photonanomedicine

Photo-induced cancer therapies, mainly including photothermal therapy (PTT) and photodynamic therapy (PDT), have attracted numerous attentions owing to the high selectivity, convenience, and few side effects. However, single PTT usually requires high laser power density, and single PDT usually needs a high photosensitizer dosage. Herein, a kind of composite nanocarrier based on clay (laponite)-polypyrrole (LP) nanodisks was synthesized via the in situ polymerization of pyrrole in the interlayer space of laponite. LP composite nanodisks were then coated with polyvinylpyrrolidone (PVP) to form the LP-PVP (LPP) composite nanodisks which show an excellent colloidal stability and in vitro and in vivo biocompatibility. The interlayer space of LPP can be further used for the loading of Chlorin e6 (Ce6), with an ultrahigh loading capacity of about 89.2%. Furthermore, the LPP nanocarrier can enhance the PDT effect of Ce6 under the irradiation of a 660 nm laser, through enhancing its solubility and cellular uptake amount. Besides, it was found that LPP nanodisks exhibit a more outstanding photothermal performance under a 980 nm near-infrared laser (NIR) than a 808 nm NIR laser, with the photothermal conversion efficiency of 45.7 and 27.7%, respectively. The in vitro and in vivo tumor therapy results evidently confirm that the Ce6-loaded LPP nanodisks have a combined tumor PTT and PDT effect, which can significantly suppress the tumor malignant proliferation.

Sulfobetaine methacrylate-functionalized graphene oxide-IR780 nanohybrids aimed at improving breast cancer phototherapy

The application of Graphene Oxide (GO) in cancer photothermal therapy is hindered by its lack of colloidal stability in biologically relevant media and modest Near Infrared (NIR) absorption. In this regard, the colloidal stability of GO has been improved by functionalizing its surface with poly(ethylene glycol) (PEG), which may not be optimal due to the recent reports on PEG immunogenicity. On the other hand, the chemical reduction of GO using hydrazine hydrate has been applied to enhance its photothermal capacity, despite decreasing its cytocompatibility. In this work GO was functionalized with an amphiphilic polymer containing [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA) brushes and was loaded with IR780, for the first time, aiming to improve its colloidal stability and phototherapeutic capacity. The attained results revealed that the SBMA-functionalized GO displays a suitable size distribution, neutral surface charge and adequate cytocompatibility. Furthermore, the SBMA-functionalized GO exhibited an improved colloidal stability in biologically relevant media, while its non-SBMA functionalized equivalent promptly precipitated under the same conditions. By loading IR780 into the SBMA-functionalized GO, its NIR absorption increased by 2.7-fold, leading to a 1.2 times higher photothermal heating. In in vitro cell studies, the combination of SBMA-functionalized GO with NIR light only reduced breast cancer cells' viability to 73%. In stark contrast, by combining IR780 loaded SBMA-functionalized GO and NIR radiation, the cancer cells' viability decreased to 20%, hence confirming the potential of this nanomaterial for cancer photothermal therapy.

IR780 loaded SBMA-coated GO displayed an improved colloidal stability in biologically relevant media and an enhanced photothermal capacity.