In Vivo and in Vitro Demonstration of Gold Nanorod Aided Photothermal Presoftening of B16F10 Melanoma for Efficient Chemotherapy Using Doxorubicin Loaded Graphene Oxide

Photothermal therapy using graphene quantum dots

The rapid development of powerful anti-oncology medicines have been possible because of advances in nanomedicine. Photothermal therapy (PTT) is a type of treatment wherein nanomaterials absorb the laser energy and convert it into localized heat, thereby causing apoptosis and tumor eradication. PTT is more precise, less hazardous, and easy-to-control in comparison to other interventions such as chemotherapy, photodynamic therapy, and radiation therapy. Over the past decade, various nanomaterials for PTT applications have been reviewed; however, a comprehensive study of graphene quantum dots (GQDs) has been scantly reported. GQDs have received huge attention in healthcare technologies owing to their various excellent properties, such as high water solubility, chemical stability, good biocompatibility, and low toxicity. Motivated by the fascinating scientific discoveries and promising contributions of GQDs to the field of biomedicine, we present a comprehensive overview of recent progress in GQDs for PTT. This review summarizes the properties and synthesis strategies of GQDs including top-down and bottom-up approaches followed by their applications in PTT (alone and in combination with other treatment modalities such as chemotherapy, photodynamic therapy, immunotherapy, and radiotherapy). Furthermore, we also focus on the systematic study of in vitro and in vivo toxicities of GQDs triggered by PTT. Moreover, an overview of PTT along with the synergetic application used with GQDs for tumor eradication are discussed in detail. Finally, directions, possibilities, and limitations are described to encourage more research, which will lead to new treatments and better health care and bring people closer to the peak of human well-being.

PDT-active upconversion nanoheaters for targeted imaging guided combinatorial cancer phototherapies with low-power single NIR excitation

A versatile nanoformulation is designed by anchoring human transferrin protein (Tf) on fluoromagnetic upconverting nanoheaters, NaGdF₄:Yb,Er (UCNP), loaded with Rose Bengal (RB), for multimodal imaging guided synergistic photothermal (PTT) and photodynamic therapy (PDT) at the targeted tumor site. The NIR excitation of the UCNP-RB Forster Resonance Energy Transfer (FRET) pair results in the reactive oxygen species (ROS) generation for PDT, whereas the non-radiative transitions in Er result in the heat required for PTT. The intravenously injected theranostic agent (UCNP@Tf-RB) enabled; (1) combinatorial PTT and PDT of 4T1 tumors with minimal systemic toxicity, (2) dual targeted (passive and active) tumor accumulation, (3) dual-modal imaging (MRI/photothermal), and, (4) excellent stability and biocompatibility. The in vitro therapy data corroborates the MRI findings that Tf conjugation resulted in actively targeted tumor accumulation via over-expressed transferrin receptors (TfR) on 4T1 cells. Real-time photothermal imaging enabled visualization of the tumor while receiving the therapy. The UCNP@Tf-RB, for synergistic PTT-PDT, and UCNP@Tf, for PTT only, caused rapid suppression of tumor with a tumor-growth inhibition index (TGII) of ~0.91, and 0.79, respectively. Histopathological examination demonstrated minimal damage to non-targeted tissues and caused significant damage to the tumor. This theranostic methodology enhances anti-cancer therapeutic efficiency, and announces the potential for pre-clinical cancer therapy.

Multifunctional graphene oxide nanoparticles for drug delivery in cancer

Recent advancements in nanotechnology have enabled us to develop sophisticated multifunctional nanoparticles or nanosystems for targeted diagnosis and treatment of several illnesses, including cancers. To effectively treat any solid tumor, the therapy should preferably target just the malignant cells/tissue with minor damage to normal cells/tissues. Graphene oxide (GO) nanoparticles have gained considerable interest owing to their two-dimensional planar structure, chemical/mechanical stability, excellent photosensitivity, superb conductivity, high surface area, and good biocompatibility in cancer therapy. Many compounds have been functionalized on the surface of GO to increase their biological applications and minimize cytotoxicity. The review presents an overview of the physicochemical characteristics, strategies for various modifications, toxicity and biocompatibility of graphene and graphene oxide, current trends in developing GO-based nano constructs as a drug delivery cargo and other biological applications, including chemo-photothermal therapy, chemo-photodynamic therapy, bioimaging, and theragnosis in cancer. Further, the review discusses the challenges and opportunities of GO, GO-based nanomaterials for the said applications. Overall, the review focuses on the therapeutic potential of strategically developed GO nanomedicines and comprehensively discusses their opportunities and challenges in cancer therapy.

The detection of fipronil residue in egg on layered gold nanorod-graphene oxide-based 3D SERS substrate

Fipronil and its metabolite fipronil sulfone, when found in some food products, such as eggs, have caused major public health concerns. In this study, we used gold nanorods (AuNRs) and graphene oxide (GO) nanocomposites to fabricate a layer-by-layer assembled three dimensional (3D) substrate for toxin detection by surface enhanced Raman scattering (SERS). The 4-layers of GO-AuNR 3D SERS substrate were optimized using rhodamine 6G. The optimized SERS substrate was used to detect fipronil and fipronil sulfone in spiked eggs. The obtained limit of detection was 10^-8 M (∼4.4 ppb), which is below the maximum residue limit in Taiwan of 10 ppb. Egg samples spiked with fipronil (10^-7 and 10^-3 M) and fipronil sulfone (10^-8 and 10^-4 M) were measured and the maximum departure of the measured SERS intensity from the calibrated SERS intensity was ∼14%. Thus, a facile screening method for the detection of fipronil/fipronil sulfone in food-grade eggs by SERS is demonstrated.

Doxorubicin-loaded gold nanorods: a multifunctional chemo-photothermal nanoplatform for cancer management

Two of the limitations associated with cancer treatment are the low efficacy and the high dose-related side effects of anticancer drugs. The purpose of the current study was to fabricate biocompatible multifunctional drug-loaded nanoscale moieties for co-therapy (chemo-photothermal therapy) with maximum efficacy and minimum side effects. Herein, we report in vitro anticancerous effects of doxorubicin (DOX) loaded on gold nanorods coated with the polyelectrolyte poly(sodium-4-styrenesulfonate) (PSS-GNRs) with and without NIR laser (808 nm, power density = 1.5 W/cm2 for 2 min) irradiation. The drug-loading capacity of PSS-GNRs was about 76% with a drug loading content of 3.2 mg DOX/mL. The cumulative DOX release significantly increased after laser exposure compared to non-irradiated samples (p < 0.05). The zeta potential values of GNRs, PSS-GNRs and DOX-PSS-GNRs were measured as 42 ± 0.1 mV, -40 ± 0.3 mV and 39.3 ± 0.6 mV, respectively. PSS-GNRs nanocomplexes were found to be biocompatible and showed higher photothermal stability. The DOX-conjugated nanocomplexes with NIR laser irradiation appear more efficient in cell inhibition (93%) than those without laser exposure (65%) and doxorubicin alone (84%). The IC50 values of PSS-GNRs-DOX and PSS-GNRs-DOX were measured as 7.99 and 3.12 µg/mL, respectively, with laser irradiation. Thus, a combinatorial approach based on chemotherapy and photothermal strategies appears to be a promising platform in cancer management.

Plasmonic photothermal microneedle arrays and single needles for minimally-invasive deep in-skin hyperthermia

We report, for the first time, crosslinked polymeric microneedle (MN) arrays and single needles (2 mm and 4.5 mm length) coated with gold nanorods (GnRs) to induce deep hyperthermia in a 3 mm-thickness skin model upon near infrared (NIR) laser irradiation.