Gold Rod-Polyethylene Glycol-Carbon Dot Nanohybrids as Phototheranostic Probes

Multifunctional Near Infrared Polymer Dots for Enhanced Synergistic Photodynamic/Photothermal Effect In Vitro

Synergistic photodynamic/photothermal therapy (PDT/PTT) can be used to target cancer cells by locally generating singlet oxygen species or increasing temperature under laser irradiation. This approach offers higher tumor ablation efficiency, lower therapeutic dose requirements, and reduced side effects compared to single treatment approaches. However, the therapeutic efficiency of PDT/PTT is still limited by the low oxygen levels within the solid tumors caused by abnormal vasculature and altered cancer cell metabolism. To address these challenges, we developed multifunctional nanoparticles with high catalytic activity for converting tumor hydrogen peroxide (H2O2) into oxygen (O2). Using poly(styrene-co-maleic anhydride) (PSMA) as a cross-linker, we generated compact, highly fluorescent Pdots, used poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT) as a near-infrared photosensitizer for both photodynamic and photothermal applications, and incorporated manganese (Mn) ions to catalyze the H2O2-to-O2 conversion. These Mn-doped Pdots significantly enhance O2 production, achieving an enhanced 1O2 quantum yield from 0.46 to 0.64 with the addition of H2O2, achieving the goal of improving PDT efficiency. With this rational design, we produced Pdots with enhanced H2O2-to-1O2 converting ability for potential use in PDT. For photothermal applications, our Pdots generate a photothermal conversion efficiency of 53%. In vitro studies using human MCF7 adenocarcinoma cells confirmed the biocompatibility of these Pdots in the absence of laser exposure with a pronounced cell killing effect under laser irradiation for synergistic PDT/PTT. These results highlight the promise of Pdots in overcoming oxygen limitations, balancing the performance of PDT/PTT, and enhancing the therapeutic efficacy of PDT/PTT in cancer cells in vitro.

Enhanced Fluorescence Imaging of Implants Based on Polyester Copolymers in Combination With MRI

Nowadays, many biodegradable materials are offered for biomedical applications, but there are only a few in vivo methods for their detection and monitoring. In this work, implants based on biodegradable polyester copolymers were labeled with indocyanine green (ICG) for fluorescence imaging in combination with tissue optical clearing (TOC) and magnetic resonance imaging (MRI). The results include in vitro degradation modeling followed by in vivo imaging of copolymer samples that were subcutaneously implanted in BALB/c mice. TOC with 70% glycerol has been demonstrated to significantly improve sample visualization. The TOC efficiency parameter Q demonstrated the variability of effects correlating with the timing of follow-up in the postimplantation period. It has been shown that nonhealing wounds, peri-implantation inflammation, or fibrosis, confirmed by MRI, affect the effectiveness of TOC in the range from Q = -30% to 70%.

Metal-Enhanced Fluorescent Carbon Quantum Dots via One-Pot Solid State Synthesis for Cell Imaging

In this study, a facile one-pot solid-state synthesis method is developed to shed light on the metal-enhanced fluorescence (MEF) effect in carbon quantum dots (CQDs) and gold nanoparticles (AuNPs) hybrid materials. This is one of the few studies on the solid-state synthesis of N-doped CQDs/gold hybrid nanomaterials. We have conducted various sets of experiments to reveal the role of individual reagents during the nucleation and growth of nanoparticles. We have demonstrated that the addition of a small amount of gold salt illustrates a paramount effect (10³-fold) in photoluminescence intensity. This effect is ascribed to MEF, which is caused due to interactions between the excited-state fluorophores and the free surface electrons of metal nanoparticles. It is interesting to note that a further increase of gold yields fluorescence quenching due to a large number of formed AuNPs causing fluorescence resonance energy transfer. By adjusting the volume ratio of gold salt and CD precursors, it is possible to obtain the CQDs-AuNPs hybrid with the highest fluorescence, which produces extensive visible light under 460 nm excitation. Synthesized materials have been successfully used for imaging human dermal fibroblasts and A549 lung epithelial cells. The dose-dependent cytotoxicity studies reveal that the hybrid structures do not have cytotoxicity.

Carbon dot/inorganic nanomaterial composites

The preparation methods, formation mechanism, properties and applications of carbon dot/inorganic nanohybrid materials are reported.

Gold Nanorods: The Most Versatile Plasmonic Nanoparticles

Gold nanorods (NRs), pseudo-one-dimensional rod-shaped nanoparticles (NPs), have become one of the burgeoning materials in the recent years due to their anisotropic shape and adjustable plasmonic properties. With the continuous improvement in synthetic methods, a variety of materials have been attached around Au NRs to achieve unexpected or improved plasmonic properties and explore state-of-the-art technologies. In this review, we comprehensively summarize the latest progress on Au NRs, the most versatile anisotropic plasmonic NPs. We present a representative overview of the advances in the synthetic strategies and outline an extensive catalogue of Au-NR-based heterostructures with tailored architectures and special functionalities. The bottom-up assembly of Au NRs into preprogrammed metastructures is then discussed, as well as the design principles. We also provide a systematic elucidation of the different plasmonic properties associated with the Au-NR-based structures, followed by a discussion of the promising applications of Au NRs in various fields. We finally discuss the future research directions and challenges of Au NRs.

Improving Image-Guided Surgical and Immunological Tumor Treatment Efficacy by Photothermal and Photodynamic Therapies Based on a Multifunctional NIR AIEgen

Multimodal therapy is attracting increasing attention to improve tumor treatment efficacy, but generally requires various complicated ingredients combined within one theranostic system to achieve multiple functions. Herein, a multifunctional theranostic nanoplatform based on a single aggregation-induced-emission luminogen (AIEgen), DDTB, is designed to integrate near-infrared (NIR) fluorescence, photothermal, photodynamic, and immunological effects. Intravenously injected AIEgen-based nanoparticles can efficiently accumulate in tumors with NIR fluorescence to provide preoperative diagnosis. Most of the tumors are excised under intraoperative fluorescence navigation, whereafter, some microscopic residual tumors are completely ablated by photodynamic and photothermal therapies for maximally killing the tumor cells and tissues. Up to 90% of the survival rate can be achieved by this synergistic image-guided surgery and photodynamic and photothermal therapies. Importantly, the nanoparticles-mediated photothermal/photodynamic therapy plus programmed death-ligand 1 antibody significantly induce tumor elimination by enhancing the effect of immunotherapy. This theranostic strategy on the basis of a single AIEgen significantly improves the survival of cancer mice with maximized therapeutic outcomes, and holds great promise for clinical cancer treatment.

Carbon Dots-Based Logic Gates

Carbon dots (CDs)-based logic gates are smart nanoprobes that can respond to various analytes such as metal cations, anions, amino acids, pesticides, antioxidants, etc. Most of these logic gates are based on fluorescence techniques because they are inexpensive, give an instant response, and highly sensitive. Computations based on molecular logic can lead to advancement in modern science. This review focuses on different logic functions based on the sensing abilities of CDs and their synthesis. We also discuss the sensing mechanism of these logic gates and bring different types of possible logic operations. This review envisions that CDs-based logic gates have a promising future in computing nanodevices. In addition, we cover the advancement in CDs-based logic gates with the focus of understanding the fundamentals of how CDs have the potential for performing various logic functions depending upon their different categories.