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Photodynamic therapy (PDT) has been extensively investigated for decades for tumor treatment because of its non-invasiveness, spatiotemporal selectivity, lower side-effects, and immune activation ability. It can be a promising treatment modality in several medical fields, including oncology, immunology, urology, dermatology, ophthalmology, cardiology, pneumology, and dentistry. Nevertheless, the clinical application of PDT is largely restricted by the drawbacks of traditional photosensitizers, limited tissue penetrability of light, inefficient induction of tumor cell death, tumor resistance to the therapy, and the severe pain induced by the therapy. Recently, various photosensitizer formulations and therapy strategies have been developed to overcome these barriers. Significantly, the introduction of nanomaterials in PDT, as carriers or photosensitizers, may overcome the drawbacks of traditional photosensitizers. Based on this, nanocomposites excited by various light sources are applied in the PDT of deep-seated tumors. Modulation of cell death pathways with co-delivered reagents promotes PDT induced tumor cell death. Relief of tumor resistance to PDT with combined therapy strategies further promotes tumor inhibition. Also, the optimization of photosensitizer formulations and therapy procedures reduces pain in PDT. Here, a systematic summary of recent advances in the fabrication of photosensitizers and the design of therapy strategies to overcome barriers in PDT is presented. Several aspects important for the clinical application of PDT in cancer treatment are also discussed. [ABSTRACT FROM AUTHOR]

Due to high carrier mobility, excellent stability, and tunable optical properties, 2D monoelemental germanene has attracted considerable attention in recent years. Herein, few-layered 2D germanium nanosheets (GeNS) were obtained via a facile liquid-phase exfoliated method and fabricated as electrode materials to assemble self-powered photo-electrochemical (PEC) type photodetectors. Such 2D GeNS-based PEC-type photodetectors exhibit a responsivity of 7.81 μA W−1, a detectivity of 5.2 × 109 Jones, and the rise and decay times of 0.15 s and 0.76 s, respectively, under simulated light. At the specific wavelength of 380 nm, it demonstrates a responsivity of 340.91 μA W−1 and a detectivity of 1.82 × 1011 Jones. In addition, the GeNS-based PEC-type device also exhibits good air-stability (over one-month). The present work demonstrates low-cost and facile fabrication techniques for preparing 2D monoelemental germanene and suggests that the as-prepared GeNS is a promising candidate for PEC-type photodetector applications. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) metal-free sheets with atomic thickness have been highly considered as promising candidates for fluorescent probes, due to their intriguing characteristics. In this work, 2D ultrathin boron nanosheets (B NSs) with a surface defect nanolayer can be effectively prepared by modified liquid phase exfoliation. The as-prepared ultrathin B NSs show blue fluorescence characteristics even with a quantum yield efficiency of up to 10.6%. Such luminescent behavior originates from the quantum confinement effect and the existence of a surface defect layer. In light of the advantages of being environmentally friendly, having high photostability and good biocompatibility, for the first time we have shown that ultrathin B NSs can be used as an emerging fluorescent probe for application in cellular bioimaging. It is believed that this work will open new avenues for ultrathin B NSs in biomedical fields, and it will also inspire the development of other elemental 2D nanomaterials.