Photoreactive Mercury-Containing Metallosupramolecular Nanoparticles with Tailorable Properties That Promote Enhanced Cellular Uptake for Effective Cancer Chemotherapy.

A new potential route to enhance the efficiency of supramolecular polymers for cancer chemotherapy was successfully demonstrated by employing a photosensitive metallosupramolecular polymer (Hg-BU-PPG) containing an oligomeric poly(propylene glycol) backbone and highly sensitive pH-responsive uracil-mercury-uracil (U-Hg-U) bridges. This route holds great promise as a multifunctional bioactive nano-object for development of more efficient and safer cancer chemotherapy. Owing to the formation of uracil photodimers induced by ultraviolet irradiation, Hg-BU-PPG can form a photo-cross-linked structure and spontaneously forms spherical nanoparticles in aqueous solution. The irradiated nanoparticles possess many unique characteristics, such as unique fluorescence behavior, highly sensitive pH-responsiveness, and intriguing phase transition behavior in aqueous solution as well as high structural stability and antihemolytic activity in biological media. More importantly, a series of cellular studies clearly confirmed that the U-Hg-U photo-cross-links in the irradiated nanoparticles substantially enhance their selective cellular uptake by cancer cells via macropinocytosis and the mercury-loaded nanoparticles subsequently induce higher levels of cytotoxicity in cancer cells (compared to non-irradiated nanoparticles), without harming normal cells. These results are mainly attributed to cancer cell microenvironment-triggered release of mercury ions from disassembled nanoparticles, which rapidly induce massive levels of apoptosis in cancer cells. Overall, the pH-sensitive U-Hg-U photo-cross-links within this newly discovered supramolecular system are an indispensable factor that offers a potential path to remarkably enhance the selective therapeutic effects of functional nanoparticles toward cancer cells.

Water-soluble graphene quantum dot-based polymer nanoparticles with internal donor/acceptor heterojunctions for efficient and selective detection of cancer cells.

We present a new, insightful donor-acceptor (D-A) energy transfer-based strategy for the preparation and development of water-soluble multifunctional pH-responsive heterojunction nanoparticles. Hydrophilic tertiary amine-grafted polythiophene (WPT) as a donor and blue fluorescent graphene quantum dots (GQD) as an acceptor spontaneously form co-assembled nanoparticles that function as a highly pH-sensitive and efficient biosensor appropriate for the detection of cancer cells. These WPT/GQD nanoparticles exhibit a number of unique physical characteristics-such as broad-range, tunable GQD-loading contents and particle sizes, extremely low cytotoxicity in normal and cancer cells, and highly sensitive pH-responsiveness and rapid acid-triggered fluorescent behavior under aqueous acidic conditions. We show these features are conferred by self-aggregation of the GQD within the nanoparticles and subsequent aggregation-induced fluorescence of GQD after disassembly of the nanoparticles and dissociation of the D-A interactions under acidic conditions. Importantly, in vitro fluorescence imaging experiments clearly demonstrated the WPT/GQD nanoparticles were gradually taken up into normal and cancer cells in vitro. Selective formation of GQD aggregates subsequently occurred in the acidic microenvironment of the cancer cells and the interior of the cancer cells exhibited strong blue fluorescence; these phenomena did not occur in normal cells. In contrast, pristine WPT and GQD did not exhibit cellular microenvironment-triggered fluorescence transitions in cancer or normal cell lines. Therefore, this newly discovered water-soluble heterojunction system may represent a strongly fluorescent highly pH-sensitive bioprobe for rapid detection of cancer cells.

Multi-Biofunctional Silver-Containing Metallosupramolecular Nanogels for Efficient Antibacterial Treatment and Selective Anticancer Therapy.

We develop a simple and efficient route for the fabrication of water-soluble metallosupramolecular polymers. We demonstrate that the introduction of environment-responsive metal-organic complexes within supramolecular polymers endows the resulting self-assembled nano-objects with outstanding antibacterial activity and may significantly improve the efficacy and safety of selective cancer therapy. Herein, we successfully developed a silver-containing supramolecular polymer (Ag-Cy-J) possessing a hydrophilic Jeffamine backbone and highly sensitive pH-responsive cytosine-silver-cytosine (Cy-Ag-Cy) linkages, which spontaneously self-assemble to produce sterically stabilized spherical nanogels in water. The resulting nanogels exhibit several attractive features such as unique fluorescence behavior in water, highly stable self-assembled structures in biological media, significant antihemolytic capability, highly sensitive pH-responsiveness and broad-spectrum antibacterial activity against various bacteria strains. Importantly, in vitro cellular assays clearly demonstrated Ag-Cy-J nanogels highly selectively target and induce cytotoxicity in cancer cells, without affecting normal cells. The selective cytotoxic activity in cancer cells is attributed to rapid dissociation of the Cy-Ag-Cy complexes within the nanogels in the cancer cell microenvironment, followed by the intracellular release of silver ions and induction of rapid, massive apoptosis. Overall, the pH-sensitive Cy-Ag-Cy complexes within this supramolecular nanogel system may provide a route to remarkably improve the efficacy of both antibacterial and cancer drug therapies. STATEMENT OF SIGNIFICANCE: We present a significant breakthrough in the development of a water-soluble silver-containing metallosupramolecular polymer (Ag-Cy-J) that spontaneously self-assembles in water into a spherical nanogel with unique physical characteristics due to the existence of highly sensitive pH-responsive cytosine-silver-cytosine (Cy-Ag-Cy) linkages within the nanogels. Importantly, a series of in vitro antibacterial and anticancer assays demonstrated the Ag-Cy-J nanogels not only exert strong antibacterial activity against various bacterial strains, but also exhibit a high degree of selective uptake and rapidly induce massive apoptosis in cancer cells without harming normal cells. Thus, this newly discovered supramolecular system may potentially provide a multi-biofunctional soft nanomaterial for efficient and safe antibacterial and cancer therapies.

A Misalignment Optical Guiding Module for Power Generation Enhancement of Fixed-Type Photovoltaic Systems.

: This study presents a misalignment light-guiding module to increase the effectiveness of absorbing light. For a general fixed-type photovoltaic (PV) panel, the misalignment light decreases the efficiency of the system. A solar tracking system was installed for obtaining higher power generation. However, the cost of the PV system and maintenance was 5-10 times higher than the general type. In this study, this module is composed of an array of misalignment light-guiding units that consist of a non-axisymmetric compound parabolic curve (NACPC) and a freeform surface collimator. The NACPC efficiently collects the misalignment light within ±30° and guides the light to the collimator. The light has a better uniformity and smaller angle at the exit aperture. The simulation results show that the optical efficiency of the unit was above 70% when the misalignment angle was smaller than 20°. The experimental results show that the power generation of the light-guiding unit was 1.8 times higher than the naked PV panel.