Inhibiting HER3 Hyperphosphorylation in HER2-Overexpressing Breast Cancer through Multimodal Therapy with Branched Gold Nanoshells

Treatment failure in breast cancers overexpressing human epidermal growth factor receptor 2 (HER2) is associated mainly to the upregulation of human epidermal growth factor receptor 3 (HER3) oncoprotein linked to chemoresitence. Therefore, to increase patient survival, here a multimodal theranostic nanoplatform targeting both HER2 and HER3 is developed. This consists of doxorubicin-loaded branched gold nanoshells functionalized with the near-infrared (NIR) fluorescent dye indocyanine green, a small interfering RNA (siRNA) against HER3, and the HER2-specific antibody Transtuzumab, able to provide a combined therapeutic outcome (chemo- and photothermal activities, RNA silencing, and immune response). In vitro assays in HER2+ /HER3+ SKBR-3 breast cancer cells have shown an effective silencing of HER3 by the released siRNA and an inhibition of HER2 oncoproteins provided by Trastuzumab, along with a decrease of the serine/threonine protein kinase Akt (p-AKT) typically associated with cell survival and proliferation, which helps to overcome doxorubicin chemoresistance. Conversely, adding the NIR light therapy, an increment in p-AKT concentration is observed, although HER2/HER3 inhibitions are maintained for 72 h. Finally, in vivo studies in a tumor-bearing mice model display a significant progressively decrease of the tumor volume after nanoparticle administration and subsequent NIR light irradiation, confirming the potential efficacy of the hybrid nanocarrier.

Novel Gold Nanorods@Thiolated Pectin on the Killing of HeLa Cells by Photothermal Ablation

Gold nanorods (AuNRs) have attracted attention in the field of biomedicine, particularly for their potential as photothermal agents capable of killing tumor cells by photothermic ablation. In this study, the synthesis of novel AuNRs stabilized with thiolated pectin (AuNR@SH-PEC) is reported. To achieve this, thiolated pectin (SH-PEC) was obtained by chemically binding cysteamine motifs to the pectin backbone. The success of the reaction was ascertained using FTIR-ATR. Subsequently, the SH-PEC was used to coat and stabilize the surface of AuNRs (AuNR@SH-PEC). In this context, different concentrations of SH-PEC (0.25, 0.50, 1.0, 2.0, 4.0, and 8.0 mg/mL) were added to 0.50 mL of AuNRs suspended in CTAB, aiming to determine the experimental conditions under which AuNR@SH-PEC maintains stability. The results show that SH-PEC effectively replaced the CTAB adsorbed on the surface of AuNRs, enhancing the stability of AuNRs without affecting their optical properties. Additionally, scanning electron and atomic force microscopy confirmed that SH-PEC is adsorbed into the surface of the AuNRs. Importantly, the dimension size (60 × 15 nm) and the aspect ratio (4:1) remained consistent with those of AuNRs stabilized with CTAB. Then, the photothermal properties of gold nanorods were evaluated by irradiating the aqueous suspension of AuNR@SH-PEC with a CW laser (808 nm, 1 W). These results showed that photothermal conversion efficiency is similar to the photothermal conversion observed for AuNR-CTAB. Lastly, the cell viability assays confirmed that the SH-PEC coating enhanced the biocompatibility of AuNR@SH-PEC. Most important, the viability cell assays subjected to laser irradiation in the presence of AuNR@SH-PEC showed a decrease in the cell viability relative to the non-irradiated cells. These results suggest that AuNRs stabilized with thiolated pectin can potentially be exploited in the implementation of photothermal therapy.

HLA-G 14 bp Ins/Del (rs66554220) Variant Is Not Associated with Breast Cancer in Women from Western Mexico

HLA-G is a physiology and pathologic immunomodulator detrimentally related to cancer. Its gene is heavily transcriptionally and post-transcriptionally regulated by variants located in regulator regions like 3'UTR, being the most studied Ins/Del of 14-bp (rs66554220), which is known to influence the effects of endogen cell factors; nevertheless, the reports are discrepant and controversial. Herein, the relationship of the 14-bp Ins/Del variant (rs66554220) with breast cancer (BC) and its clinical characteristics were analyzed in 182 women with non-familial BC and 221 disease-free women as a reference group. Both groups from western Mexico and sex-age-matched (sm-RG). The rs66554220 variant was amplified by SSP-PCR and the fragments were visualized in polyacrylamide gel electrophoresis. The variant rs66554220 was not associated with BC in our population. However, we suggest the Ins allele as a possible risk factor for developing BC at clinical stage IV (OR = 3.05, 95% CI = 1.16-7.96, p = 0.01); nevertheless, given the small stratified sample size (n = 11, statistical power = 41%), this is inconclusive. In conclusion, the 14-bp Ins/Del (rs66554220) variant of HLA-G is not associated with BC in the Mexican population, but might be related to advanced breast tumors. Further studies are required.

Evaluation of a Polymeric Topical Formulation of Endoxifen in an Estrogen Receptor Positive Breast Cancer Murine Model

Breast cancer (BC) has surpassed lung cancer as the most diagnosed cancer and, in terms of mortality, is the fifth leading cause with 684,996 new deaths (6.7% of all cancer-related deaths) and the highest mortality amongst all cancers (15.5%) in women. Selective estrogen-receptor modulators (SERMs) have been used for the last thirty years for estrogen receptor-positive (ER+) breast cancer prevention and treatment. Tamoxifen (TAM), the most widely used SERM, is orally administered and its long-term oral administration has been associated to toxicity and adverse side effects. Endoxifen (EDX) is one of the known active metabolites of TAM, with an affinity to ERα 100 times higher than TAM. Furthermore, EDX has shown antiproliferative activity against the ER+ breast cancer cell line MCF-7. Alternative administration routes that avoid the metabolic processing of TAM seem an appealing alternative to its oral administration. With this aim, we have prepared a polymeric gel-like solution of Pluronic® F127 as vehicle for topical administration of EDX. In order to shed light on the potential clinical use of this formulation we have compare it with the standard pharmaceutical form, i.e. orally administered TAM. The biodistribution, antitumor efficacy and toxic effects of topical EDX and oral TAM were evaluated in ER+ tumor xenograft athymic nu/nu mouse models. The results showed a statistically significant antitumor effect and reduced toxicity of topical EDX as compared to oral TAM or empty F127 gel. This novel administration route of SERMs could also have a strong impact in the prevention of BC at early development stages and could help to ameliorate the mortality and morbidity related to this disease.

Pluronic F127 and P104 Polymeric Micelles as Efficient Nanocarriers for Loading and Release of Single and Dual Antineoplastic Drugs

The potential application of biodegradable and biocompatible polymeric micelles formed by Pluronic F127 and P104 as nanocarriers of the antineoplastic drugs docetaxel (DOCE) and doxorubicin (DOXO) is presented in this work. The release profile was carried out under sink conditions at 37 °C and analyzed using the Higuchi, Korsmeyer-Peppas, and Peppas-Sahlin diffusion models. The cell viability of HeLa cells was evaluated using the proliferation cell counting kit CCK-8 assay. The formed polymeric micelles solubilized significant amounts of DOCE and DOXO, and released them in a sustained manner for 48 h, with a release profile composed of an initial rapid release within the first 12 h followed by a much slower phase the end of the experiments. In addition, the release was faster under acidic conditions. The model that best fit the experimental data was the Korsmeyer-Peppas one and denoted a drug release dominated by Fickian diffusion. When HeLa cells were exposed for 48 h to DOXO and DOCE drugs loaded inside P104 and F127 micelles, they showed lower IC₅₀ values than those reported by other researchers using polymeric nanoparticles, dendrimers or liposomes as alternative carriers, indicating that a lower drug concentration is needed to decrease cell viability by 50%.

Study of the interaction of folic acid-modified gold nanorods and fibrinogen through microfluidics: implications for protein adsorption, incorporation and viability of cancer cells

Gold nanoparticles (GNPs) are an attractive nanomaterial for potential applications in therapy and diagnostics due to their capability to direct toward specific sites in the organism. However, when exposed to plasma, GNPs can interact with different biomolecules that form a dynamic nano-bio interface called a "protein corona" (PC). Remarkably, the PC could affect multiple biological processes, such as cell targeting and uptake, cytotoxicity, and nanoparticle (NP) clearance. The interaction of nanomaterials with plasmatic proteins has been widely studied under bulk conditions, however, under dynamic conditions, it has just recently been explored. Thus, to mimic a dynamic natural environment found in arteries and veins, microfluidic devices were used. In this work, gold nanorods (GNRs) were synthesized and conjugated with polyethylene glycol (PEG) to reduce their interaction with plasma proteins and increase their biocompatibility. Then, GNRs were functionalized with folic acid, a targeting ligand typically used to recognize tumor cells. The resulting nanosystem was exposed to fibrinogen (FB) to study the development and biological impact of PC formation through two strategies: bulk and laminar flow conditions. The obtained nanosystems were characterized by absorption spectrophotometry, DLS, laser Doppler microelectrophoresis, neutron activation analysis, circular dichroism spectroscopy and TEM. Finally, cell viability and cellular uptake assays were performed to study the influence of the PC on the cell viability and delivery of nanosystems.

High antibacterial performance of hydrophobic chitosan-based nanoparticles loaded with Carvacrol

Bacterial infections have become one of the top ten public health concerns worldwide. These problems are aggravated with the emergence of multi-drug resistant bacterial strains. Thus, it is necessary to adopt novel technological strategies, such as development of bionanomaterials to prevent the infection, and treat this kind of bacteria. At this regard, the chemical modification of chitosan (Cs), by the covalent attachment of a hydrocarbon chain (octanoic acid), was developed to obtain hydrophobic chitosan (HCs). Then, HCs was used to synthetize nanoparticles using the well-known ionotropic gelation approach, optimizing the parameters, such as the TPP/HCs ratio and pH solution to get stable nanoparticles. Then, carvacrol (CAR) was loaded into NPs (HCs-CAR NPs) using different concentrations of 25%, 50% and 75% (%w/w CAR/HCs). The physicochemical properties for HCs-CAR NPs prepared at 50% of CAR stood out from the rest, showing a spherical morphology, with a size of 200 nm, Z potential of 10.4 mV and encapsulation efficiency of 56.28%. These formulations were chosen to evaluate the antibacterial activity, using Gram-negative (Escherichia coli) and Gram-positive bacterial model (Staphylococcus aureus). The HCs-CAR NPs showed great activity against both bacterial models, being more effective against Gram (+) strain (S. aureus), suggesting the potential application of these NPs as novel biomaterial to treat bacterial infection.

Microfluidics-assisted conjugation of chitosan-coated polymeric nanoparticles with antibodies: Significance in drug release, uptake, and cytotoxicity in breast cancer cells

Nanoparticle-based drug delivery systems, in combination with high-affinity disease-specific targeting ligands, provide a sophisticated landscape in cancer theranostics. Due to their high diversity and specificity to target cells, antibodies are extensively used to provide bioactivity to a plethora of nanoparticulate systems. However, controlled and reproducible assembly of nanoparticles (NPs) with these targeting ligands remains a challenge. In this context, determinants such as ligand density and orientation, play a significant role in antibody bioactivity; nevertheless, these factors are complicated to control in traditional bulk labeling methods. Here, we propose a microfluidic-assisted methodology using a polydimethylsiloxane (PDMS) Y-shaped microreactor for the covalent conjugation of Trastuzumab (TZB), a recombinant antibody targeting HER2 (human epidermal growth factor receptor 2), to doxorubicin-loaded PLGA/Chitosan NPs (PLGA/DOX/Ch NPs) using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysulfosuccinimide (sNHS) mediated bioconjugation reactions. Our labeling approach led to smaller and less disperse nanoparticle-antibody conjugates providing differential performance when compared to bulk-labeled NPs in terms of drug release kinetics (fitted and analyzed with DDSolver), cell uptake/labeling, and cytotoxic activity on HER2 + breast cancer cells in vitro. By controlling NP-antibody interactions in a laminar regime, we managed to optimize NP labeling with antibodies resulting in ordered coronas with optimal orientation and density for bioactivity, providing a cheap and reproducible, one-step method for labeling NPs with globular targeting moieties.

Selective estrogen receptor modulators in the prevention of breast cancer in premenopausal women: a review

The detection of premenopausal women at high risk of breast cancer is key to chemoprevention. Therapy with selective estrogen receptor modulators (SERMs) induces a significant antiproliferative effect in estrogen receptor (ER) positive breast cancer. This review was designed according the guidelines of the 2009 PRISMA statement. Searching different databases, including PubMed, MedlinePlus, PLoS One, Cochrane Breast Cancer Specialized Register, Clinical Trials.gov and American Society of Clinical Oncology. From 168 records screened, 15 full text articles were assessed for eligibility and only 7 studies met the inclusion criteria. Three of the studies included analyzed changes in Ki-67 expression, revealing weaker expression after treatment with acolbifene and raloxifene (P<0.001). Three studies also analyzed the breast volume by magnetic resonance imagining (MRI) and demonstrate a significant difference after 1 year with raloxifene treatment (P=0.0017). Moreover, a 20% reduction in breast density was observed after a 2-year treatment with tamoxifen in premenopausal women. SERMs reduce the risk of developing breast cancer. The studies reviewed here demonstrate the modulation of Ki-67 expression and changes in breast density, suggesting an important preventive role for this group of drugs in prevention for premenopausal women at high risk of developing breast cancer.

Biodegradable photoresponsive nanoparticles for chemo-, photothermal- and photodynamic therapy of ovarian cancer

Ovarian cancer (OC) is the deadliest gynecological cancer. Standard treatment of OC is based on cytoreductive surgery followed by chemotherapy with platinum drugs and taxanes; however, innate and acquired drug-resistance is frequently observed followed by a relapse after treatment, thus, more efficient therapeutic approaches are required. Combination therapies involving phototherapies and chemotherapy (the so-called chemophototherapy) may have enhanced efficacy against cancer, by attacking cancer cells through different mechanisms, including DNA-damage and thermally driven cell membrane and cytoskeleton damage. We have designed and synthesized poly(lactic-co-glycolic) nanoparticles (PLGA NPs) containing the chemo-drug carboplatin (CP), and the near infrared (NIR) photosensitizer indocyanine green (ICG). We have evaluated the drug release profile, the photodynamic ROS generation and photothermal capacities of the NPs. Also, the antitumoral efficiency of the NPs was evaluated using the SKOV-3 cell line as an in vitro OC model, observing an enhanced cytotoxic effect when irradiating cells with an 800 nm laser. Evidence here shown supports the potential application of the biodegradable photoresponsive NPs in the clinical stage due to the biocompatibility of the materials used, the spatiotemporal control of the therapy and, also, the less likely development of resistance against the combinatorial therapy.

The -174G>C and -596G>A Polymorphisms Are Not Associated with Circulating IL-6 Levels in Breast Cancer Patients from Jalisco, México

Introduction: Interleukin-6 (IL-6) is a circulating proinflammatory cytokine that fulfills an important role in the survival and proliferation of cancer cells. Overexpression of IL-6, possibly due to the -174G>C and -596G>A polymorphisms in the IL6 gene, has been shown to be related to breast cancer (BC) and a more aggressive course of the disease. Aim: To determine the influence of the -174G>C and -596G>A polymorphisms of the IL6 gene on the circulating levels of IL-6 in BC patients from Jalisco, México. Methodology: Genotyping of the two polymorphisms was carried out on 208 BC patients and 219 healthy controls through polymerase chain reaction-restriction fragment length polymorphism analyses. In addition, the plasma IL-6 concentration levels were measured in the BC patients. Results: There was no significant association between BC and the IL-6 alleles and genotypes (-174G>C, p = 0.276; -596G>A, p = 0.762) under study. Similarly, there were no significant differences in the mean plasma IL-6 concentrations associated with the polymorphisms that were analyzed (-174G>C, p = 0.839; -596G>A, p = 0.848). Conclusions: No evidence was found that the analyzed polymorphisms are associated with the IL-6 expression or concentration in patients suffering from BC from Jalisco, Mexico.

Cisplatin-loaded PLGA nanoparticles for HER2 targeted ovarian cancer therapy

The conventional treatment (cytoreduction combined with cisplatin/carboplatin and taxane drugs) of ovarian cancer has a high rate of failure and recurrence despite a favorable initial response. This lack of success is usually attributed to the development of multidrug resistance mechanisms by cancer cells and avoidance of the anti-growth effects of monoclonal targeted therapeutic antibodies. The disease, like other cancers, is characterized by the overexpression of molecular markers, including HER2 receptors. Preclinical and clinical studies with trastuzumab, a HER2-targeted therapeutic antibody, reveal a low improvement of the outcomes of HER2 positive ovarian cancer patients. Therefore, here, we propose a cisplatin-loaded, HER2 targeted poly(lactic-co-glycolic) nanoplatform, a system capable to escape the drug-efflux effect and to take advantage of the overexpressed HER2 receptors, using them as docks for targeted chemotherapy. The NP/trastuzumab ratio was determined after fluorescein labeling of antibodies and quantification of fluorescence in NPs. The system was also characterized in terms of size, zeta potential, drug release kinetics, cytotoxicity and cellular internalization in the epithelial ovarian cancer cell line SKOV-3, and compared with the HER2 negative breast cancer cell line HCC70. Our results show an increased cytotoxicity of NPs as compared to free cisplatin, and moreover, an enhanced internalization and cytotoxicity due to the bionfunctionalization of NPs with the monoclonal antibody.

Rational Surface Engineering of Colloidal Drug Delivery Systems for Biological Applications

The use of colloidal particles as drug delivery carriers holds a great promise in terms of improvement of traditional treatment and diagnosis of human diseases. Nano- and microsized particles of a different composition including organic and inorganic materials can be fabricated with a great control over size, shape and surface properties. Nevertheless, only some few formulations have surpassed the benchtop and reached the bedside. The principal obstacle of colloidal drug delivery systems is their poor accumulation in target tissues, organs and cells, mainly by efficient sequestration and elimination by the mononuclear phagocytic system. Recent evidence suggests that, besides size, the surface character of colloidal systems is the most determinant design parameter that may ultimately guarantee successful biological performance. To approach these issues, materials designers and engineers can make use of multiple strategies and tools to finely modulate the particles' surface towards highly efficient and biocompatible materials. In this article, we provide an overview of the most relevant colloidal drug delivery systems, a summary of the available literature regarding the effects of surface charge, hydrophobicity and softness on biological response, and finally, we review the key points of surface modification strategies with organic, inorganic and biological materials.

Gold Nanorod-Based Nanohybrids for Combinatorial Therapeutics

In this work, multifunctional nanocarriers consisting of poly(sodium-4-styrenesulfonate) (PSS)/doxorubicin (DOXO)/poly-l-lysine hydrobromide (PLL)/hyaluronic acid (HA)-coated and (PSS/DOXO/PLL)₂/HA-coated gold nanorods were assembled by the layer-by-layer technique with the aims of coupling the plasmonic photothermal properties of the metal nanoparticles for plasmonic hyperthermia and the chemoaction of drug DOXO for potential intended combinatorial cancer therapeutics in the future as well as providing different strategies for the controlled and sustained release of the cargo drug molecules. To do that, DOXO could be successfully loaded onto the hybrid nanoconstructs through electrostatic interactions with high efficiencies of up to ca. 78.3 ± 6.9% for the first formed drug layer and 56 ± 13% for the second one, with a total efficiency for the whole system [(PSS/DOXO/PLL)₂/HA-coated NRs] of ca. 65.7 ± 1.4%. Nanohybrid internalization was observed to be enhanced by the outer HA layer, which is able to target the CD44 receptors widely overexpressed in some types of cancers as lung, breast, or ovarian ones. Hence, these nanohybrid systems might be versatile nanoplatforms to simultaneously deliver sufficient heat for therapeutic plasmonic hyperthermia and the anticancer drug. Two controlled mechanisms were proposed to modulate the release of the chemodrug, one by means of the enzymatic degradable character of the PLL layer and another by the modulation of the interactions between the polymeric layers through the exploitation of the optical properties of the hybrid particles under near infrared (NIR) laser irradiation. The combination of this bimodal therapeutic approach exerted a synergistic cytotoxic effect on both HeLa and MDA-MB-231 cancer cells in vitro. Cell death mechanisms were also analyzed, elucidating that plasmonic photothermal therapy induces cell necrosis, whereas DOXO activates the cell apoptotic pathway. Therefore, the present NIR laser-induced targeted cancer thermo/chemotherapy represents a novel targeted anticancer strategy with easy control on demand and suitable therapeutic efficacy.

Easy and Efficient Cell Tagging with Block Copolymer-Based Contrast Agents for Sensitive MRI Detection in Vivo

Superparamagnetic iron oxide nanoparticles (MNPs) together with magnetic resonance imaging (MRI) are the preferred tools for monitoring the fate and biodistribution of administered cells in stem cell therapy studies. Commercial MNPs need transfection agents and long incubation times for sufficient cell labeling and further in vivo cell detection. In this work, we have synthesized MNPs coated with pluronic F127 and tetronic 908, and validated their applicability as contrast agents for MRI cell detection on two different cell types: rat mesenchymal stem cells (MSCs) and multipotent neural progenitor cell line from mice (C17.2). No transfection agent was needed for a complete MNP internalization, and the uptake was only dependent on MNP concentration in medium and limited on the incubation time. By combining in vivo MRI and ex vivo histology microscopy, we have demonstrated the MRI signal detected corresponded exclusively to labeled cells and not to free particles. Pluronic F127- and tetronic 908-coated MNPs represent promising contrast agents for stem cell tracking due to their ease of use in preparation, their efficiency for cell labeling, and their high sensitivity for in vivo cell detection.

Photothermal conversion efficiency and cytotoxic effect of gold nanorods stabilized with chitosan, alginate and poly(vinyl alcohol)

Gold nanorods (GNR) use has been proposed in medical applications because of their intrinsic photothermal properties. However, the presence of CTAB molecules adsorbed onto the surface of GNRs results in a highly cytotoxic GNR system. In this work we replace the CTAB molecules with a thiolated chitosan. Once chitosan coated GNRs (Chi-SH-GNR) were attained, a film of alginate (Alg-Chi-SH-GNR) or polyvinyl alcohol (PVA-Chi-SH-GNR) was deposited onto the surface of Chi-GNR by a layer-by-layer process. The photothermal conversion efficiency for the GNR systems was determined irradiating the GNRs suspended in aqua media with a CW 808nm diode laser (CNI, China). The cytotoxicity effect and the photothermal cellular damage of GNR systems were evaluated on a breast cancer cell line. Results show that polymer coats did not affect the transduction photothermal efficiency. Values around 50% were obtained for the different coated gold nanorods. The cytotoxicity of coated gold nanorods diminished significantly compared with those GNR stabilized with CTAB. The laser irradiation of cells treated with gold nanorods showed a decrease in their viability compared with the cells treated but no irradiated.

Intraarterial route increases the risk of cerebral lesions after mesenchymal cell administration in animal model of ischemia

Mesenchymal stem cells (MSCs) are a promising clinical therapy for ischemic stroke. However, critical parameters, such as the most effective administration route, remain unclear. Intravenous (i.v.) and intraarterial (i.a.) delivery routes have yielded varied outcomes across studies, potentially due to the unknown MSCs distribution. We investigated whether MSCs reached the brain following i.a. or i.v. administration after transient cerebral ischemia in rats, and evaluated the therapeutic effects of both routes. MSCs were labeled with dextran-coated superparamagnetic nanoparticles for magnetic resonance imaging (MRI) cell tracking, transmission electron microscopy and immunohistological analysis. MSCs were found in the brain following i.a. but not i.v. administration. However, the i.a. route increased the risk of cerebral lesions and did not improve functional recovery. The i.v. delivery is safe but MCS do not reach the brain tissue, implying that treatment benefits observed for this route are not attributable to brain MCS engrafting after stroke.

Development of ordered metal nanoparticle arrangements on solid supports by combining a green nanoparticle synthetic method and polymer templating for sensing applications

One step, simple, robust and "green" methodology to fabricate high-density ordered arrays of uniform gold nanoparticles and gold nanoparticles clusters at room temperature over large areas which are suitable for high-performance SERS.

Polymeric-gold nanohybrids for combined imaging and cancer therapy

Here, the use of folic acid (FA)-functionalized, doxorubicin (DOXO)/superparamagnetic iron oxide nanoparticles (SPION)-loaded poly(lactic-co-glycolic acid) (PLGA)-Au porous shell nanoparticles (NPs) as potential nanoplatforms is reported for targeted multimodal chemo- and photothermal therapy combined with optical and magnetic resonance imaging in cancer. These polymeric-gold nanohybrids (PGNH) are produced by a seeded-growth method using chitosan as an electrostatic "glue" to attach Au seeds to DOXO/SPION-PLGA NPs. In order to determine their potential as theranostic nanoplatforms, their physicochemical properties, cellular uptake, and photothermal and chemotherapeutic efficiencies are tested in vitro using a human cervical cancer (HeLa) cell line. The present NPs show a near-infrared (NIR)-light-triggered release of cargo molecules under illumination and a great capacity to induce localized cell death in a well-focused region. The functionalization of the PGNH NPs with the targeting ligand FA improves their internalization efficiency and specificity. Furthermore, the possibility to guide the PGNH NPs to cancer cells by an external magnetic field is also proven in vitro, which additionally increases the cellular uptake and therapeutic efficiency.

Simple control of surface topography of gold nanoshells by a surfactant-less seeded-growth method

We report the synthesis of branched gold nanoshells (BGNS) through a seeded-growth surfactant-less method. This was achieved by decorating chitosan-Pluronic F127 stabilized poly(lactic-co-gycolic) acid nanoparticles (NPs) with Au seeds (NP-seed), using chitosan as an electrostatic self-assembling agent. Branched shells with different degrees of anisotropy and optical response were obtained by modulating the ratios of HAuCl4/K2CO3 growth solution, ascorbic acid (AA) and NP-seed precursor. Chitosan and AA were crucial in determining the BGNS size and structure, acting both as coreductants and structure directing growth agents. Preliminary cytotoxicity experiments point to the biocompatibility of the obtained BGNS, allowing their potential use in biomedical applications. In particular, these nanostructures with "hybrid" compositions, which combine the features of gold nanoshells and nanostars showed a better performance as surface enhanced Raman spectroscopy probes in detecting intracellular cell components than classical smoother nanoshells.

Fluorescent drug-loaded, polymeric-based, branched gold nanoshells for localized multimodal therapy and imaging of tumoral cells

Here we report the synthesis of PLGA/DOXO-core Au-branched shell nanostructures (BGNSHs) functionalized with a human serum albumin/indocyanine green/folic acid complex (HSA-ICG-FA) to configure a multifunctional nanotheranostic platform. First, branched gold nanoshells (BGNSHs) were obtained through a seeded-growth surfactant-less method. These BGNSHs were loaded during the synthetic process with the chemotherapeutic drug doxorubicin, a DNA intercalating agent and topoisomerase II inhibitior. In parallel, the fluorescent near-infrared (NIR) dye indocyanine green (ICG) was conjugated to the protein human serum albumin (HSA) by electrostatic and hydrophobic interactions. Subsequently, folic acid was covalently attached to the HSA-ICG complex. In this way, we created a protein complex with targeting specificity and fluorescent imaging capability. The resulting HSA-ICG-FA complex was adsorbed to the gold nanostructures surface (BGNSH-HSA-ICG-FA) in a straightforward incubation process thanks to the high affinity of HSA to gold surface. In this manner, BGNSH-HSA-ICG-FA platforms were featured with multifunctional abilities: the possibility of fluorescence imaging for diagnosis and therapy monitoring by exploiting the inherent fluorescence of the dye, and a multimodal therapy approach consisting of the simultaneous combination of chemotherapy, provided by the loaded drug, and the potential cytotoxic effect of photodynamic and photothermal therapies provided by the dye and the gold nanolayer of the hybrid structure, respectively, upon NIR light irradiation of suitable wavelength. The combination of this trimodal approach was observed to exert a synergistic effect on the cytotoxicity of tumoral cells in vitro. Furthermore, FA was proved to enhance the internalization of nanoplatform. The ability of the nanoplatforms as fluorescence imaging contrast agents was tested by preliminary analyzing their biodistribution in vivo in a tumor-bearing mice model.

NIR-light active hybrid nanoparticles for combined imaging and bimodal therapy of cancerous cells

Multifunctional hybrid polymeric-based nanoplatforms for simultaneous fluorescence and magnetic resonance imaging and multimodal chemo- and phothermal therapies.