Induction of autophagy-dependent and caspase- and microtubule-acetylation-independent cell death by phytochemical-stabilized gold nanopolygons in colorectal adenocarcinoma cells.

Collective functionalization of the phytochemicals of medicinal herbs on nanoparticles is emerging as a potential cancer therapeutic strategy. This study presents the facile synthesis of surface-functionalized gold nanoparticles using Bacopa monnieri (Brahmi; Bm) phytochemicals and their therapeutically relevant mechanism of action in the colorectal cancer cell line, HT29. The nanoparticles were characterized using UV-visible spectroscopy, TEM-EDAX, zeta potential analysis, TGA, FTIR and 1H NMR spectroscopy, and HR-LC-MS. The particles (Bm-GNPs) were of polygonal shape and were stable against aggregation. They entered the target cells and inhibited the viability and clonogenicity of the cells with eight times more antiproliferative efficacy (25 ± 1.5 µg mL-1) than Bm extract (Bm-EX). In vitro studies revealed that Bm-GNPs bind tubulin (a protein crucial in cell division and a target of anticancer drugs) and disrupt its helical structure without grossly altering its tertiary conformation. Like other antitubulin agents, Bm-GNPs induced G2/M arrest and ultimately killed the cells, as confirmed using flow cytometry analyses. ZVAD-FMK-mediated global pan-caspase inhibition and the apparent absence of cleaved caspase-3 in treated cells indicated that the death did not involve the classic apoptosis pathway. Cellular ultrastructure analyses, western immunoblots, and in situ immunofluorescence visualization of cellular microtubules revealed microtubule-acetylation-independent induction of autophagy as the facilitator of cell death. Together, the data indicate strong antiproliferative efficacy and a possible mechanism of action for these designer nanoparticles. Bm-GNPs, therefore, merit further investigations, including preclinical evaluations, for their therapeutic potential as inducers of non-apoptotic cell death.

Nanographene-Au fine-tuning to intensify plasmonic-resonance of polymeric hybrid bionanosystem for synergistic phototherapy and nerve photobiomodulation.

Here, we report the multi-photo-bioactivity of the plasmonic-nano graphitic coordinated polycaprolactone-based aligned nanofibrous scaffolds-based bionanosystem for photothermal breast and colon cancer therapies and peripheral nerve photobiomodulation. The size-optimized colloidal reduced graphene oxide (nRGO, 180 nm) nanosheets, for enhanced photothermal impact, were surface-functionalized with gold nanospheres (AuNPs) to prepare the nRGO@AuNP monodispersed nano-composite and then doped 2.0 mg of nRGO@AuNP in biocompatible and biodegradable polymer polycaprolactone (PCL) to fabricate the nRGO@AuNP-PCL (2.0 mg) plasmonic aligned nanofibrous scaffolds. More than 90% of cancer cells, breast cancer (MCF-7) as well as colon cancer (CT-26), ablated after 5 min of low NIR (808 nm) laser power (0.72 W/cm2) illumination with nRGO@AuNP-PCL (2.0 mg) aligned nanofibrous scaffolds. Besides, the nRGO@AuNP-PCL (2.0 mg) provided an extraordinary microenvironment for adhesion, nerve growth, proliferation, and differentiation of PC12 and S42 cells which mimics the natural extracellular matrix. The 2.5-fold increase in neurite length was observed with NIR illumination after 3 days whereas 1.7-fold was found without NIR illumination after 7 days in comparison to PCL (pure). The current findings will be useful to provide a new crucial approach for preparing biocompatible multifunctional composite plasmonic nanofibers as a highly efficient distinct platform for photothermal therapies and promising bioimplants to overcome the loss of sensation after cancer surgery through nerve photobiomodulation.

Modulation of calcium-influx by carboxymethyl tamarind­gold nanoparticles promotes biomineralization for tissue regeneration.

Gold nanoparticles (AuNPs) have been reported to modulate bone tissue regeneration and are being extensively utilized in biomedical implementations attributable to their low cytotoxicity, biocompatibility and simplicity of functionalization. Lately, biologically synthesized nanoparticles have acquired popularity because of their environmentally acceptable alternatives for diverse applications. Here we report the green synthesis of AuNPs by taking the biopolymer Carboxymethyl Tamarind (CMT) as a unique reducing as well as a stabilizing agent. The synthesized CMT-AuNPs were analyzed by UV-vis spectrophotometer, DLS, FTIR, XRD, TGA, SEM and TEM. These results suggest that CMT-AuNPs possess an average size of 19.93 ± 8.52 nm and have long-term stability. Further, these CMT-AuNPs promote the proliferation together with the differentiation and mineralization of osteoblast cells in a "dose-dependent" manner. Additionally, CMT-AuNPs are non-toxic to SD rats when applied externally. We suggest that the CMT-AuNPs have the potential to be a suitable and non-toxic agent for differentiation and mineralization of osteoblast cells in vitro and this can be tested in vivo as well.

Bionic nanotheranostic for multimodal imaging-guided NIR-II-photothermal cancer therapy.

In photothermal therapy (PTT), the photothermal conversion of the second near-infrared (NIR-II) window allows deeper penetration and higher laser irradiance and is considered a promising therapeutic strategy for deep tissues. Since cancer remains a leading cause of deaths worldwide, despite the numerous treatment options, we aimed to develop an improved bionic nanotheranostic for combined imaging and photothermal cancer therapy. We combined a gold nanobipyramid (Au NBP) as a photothermal agent and MnO2 as a magnetic resonance enhancer to produce core/shell structures (Au@MnO2; AM) and modified their surfaces with homologous cancer cell plasma membranes (PM) to enable tumour targeting. The performance of the resulting Au@MnO2@PM (AMP) nanotheranostic was evaluated in vitro and in vivo. AMP exhibits photothermal properties under NIR-II laser irradiation and has multimodal in vitro imaging functions. AMP enables the computed tomography (CT), photothermal imaging (PTI), and magnetic resonance imaging (MRI) of tumours. In particular, AMP exhibited a remarkable PTT effect on cancer cells in vitro and inhibited tumour cell growth under 1064 nm laser irradiation in vivo, with no significant systemic toxicity. This study achieved tumour therapy guided by multimodal imaging, thereby demonstrating a novel strategy for the use of bionic gold nanoparticles for tumour PTT under NIR-II laser irradiation.

Size Dependence of Gold Nanorods for Efficient and Rapid Photothermal Therapy.

In recent years, gold nanomaterials have become a hot topic in photothermal tumor therapy due to their unique surface plasmon resonance characteristics. The effectiveness of photothermal therapy is highly dependent on the shape and size of gold nanoparticles. In this work, we investigate the photothermal therapeutic effects of four different sizes of gold nanorods (GNRs). The results show that the uptake of short GNRs with aspect ratios 3.3-3.5 by cells is higher than that of GNRs with aspect ratios 4-5.5. Using a laser with single pulse energy as low as 28 pJ laser for 20 s can induce the death of liver cancer cells co-cultured with short GNRs. Long GNRs required twice the energy to achieve the same therapeutic effect. The dual-temperature model is used to simulate the photothermal response of intracellular clusters irradiated by a laser. It is found that small GNRs are easier to compact because of their morphological characteristics, and the electromagnetic coupling between GNRs is better, which increases the internal field enhancement, resulting in higher local temperature. Compared with a single GNR, GNR clusters are less dependent on polarization and wavelength, which is more conducive to the flexible selection of excitation laser sources.

Treatment of dental biofilm-forming bacterium Streptococcus mutans using tannic acid-mediated gold nanoparticles.

Biosynthesized gold nanoparticles (AuNPs) are highly attracted as a biocompatible nanodrug to treat various diseased conditions in humans. In this study, phytochemical tannic acid-mediated AuNPs (TA-AuNPs) are successfully synthesized and tested for antibacterial and antibiofilm activity against dental biofilm-forming Streptococcus mutans biofilm. The synthesized TA-AuNPs are appeared as spherical in shape with an average size of 19 nm. The antibacterial potential of TA-AuNPs was evaluated using ZOI and MIC measurements; while, antibiofilm efficacy was measured by checking the eradication of preformed biofilm on the tooth model. The ZOI and MIC values for TA-AuNPs are 25 mm in diameter and 4 µg/mL, respectively. The MTT assay, CLSM, and SEM results demonstrate that the preformed S. mutans biofilm is completely eradicated at 4xMIC (16 µg/mL) of TA-AuNPs. Finally, the present study reveals that the synthesized TA-AuNPs might be a great therapeutic drug to treat dental biofilm-forming bacterium S. mutans.

A tumor-targeted and enzyme-responsive gold nanorod-based nanoplatform with facilitated endo-lysosomal escape for synergetic photothermal therapy and protein therapy.

To tackle the obstacles related to tumor targeting and overcome the limitations of single treatment models, we have developed a nanoplatform that is both tumor-targeted and enzyme-responsive. This nanoplatform integrates photothermal gold nanorods (AuNRs) and protein drugs into a single system. This nanosystem, known as AuNRs@HA-mPEG-Deta-LA, was fabricated by modifying gold nanorods (AuNRs) with a polymeric ligand called hyaluronic acid-grafted-(mPEG/diethylenetriamine-conjugated-lipoic acid). The purpose of this fabrication was to load cytochrome c (CC) and utilize it for the synergetic protein-photothermal therapy of cancer. The resulting nanoplatform exhibited a high efficiency in loading proteins and demonstrated excellent stability in different biological environments. Additionally, CC-loaded AuNRs@HA-mPEG-Deta-LA not only enabled localized hyperthermia for photothermal therapy (PTT) with laser irradiation but also facilitated the release of CC under the action of hyaluronidase, an enzyme known to be overexpressed in tumor cells. The confocal imaging results demonstrated that the presence of a specific polymeric ligand on this nanoparticle enhances the internalization of CD44-positive cancer cells, accelerates endo/lysosomal escape, and facilitates the controlled release of CC within the cells. Furthermore, the results of the MTT assay also showed that AuNRs@HA-mPEG-Deta-LA as a protein nanocarrier demonstrated excellent biocompatibility. Importantly, this synergistic therapeutic strategy effectively induced apoptosis in A549 cancer cells by increasing the intracellular concentration of CC and utilizing the photothermal conversion of AuNRs, which was observed to be more effective compared to using only protein therapy or PTT. Therefore, this study showcased a nanoplatform based on AuNRs that has great potential for tumor-targeted protein delivery in combination with PTT in cancer treatment.

Protein-Functionalized Gold Nanospheres with Tunable Photothermal Efficiency for the Near-Infrared Photothermal Ablation of Biofilms.

Temperature-responsive nanostructures with high antimicrobial efficacy are attractive for therapeutic applications against multidrug-resistant bacteria. Here, we report temperature-responsive nanospheres (TRNs) engineered to undergo self-association and agglomeration above a tunable transition temperature (Tt). The temperature-responsive behavior of the nanoparticles is obtained by functionalizing citrate-capped spherical gold nanoparticles (AuNPs) with elastin-like polypeptides (ELPs). Using protein design principles, we achieve a broad range of attainable Tt values and photothermal conversion efficiencies (η). Two approaches were used to adjust this range: First, by altering the position of the cysteine residue used to attach ELP to the AuNP, we attained a Tt range from 34 to 42 °C. Then, by functionalizing the AuNP with an additional small globular protein, we could extend this range to 34-50 °C. Under near-infrared (NIR) light exposure, all TRNs exhibited reversible agglomeration. Moreover, they showed an enhanced photothermal conversion efficiency in their agglomerated state relative to the dispersed state. Despite their spherical shape, TRNs have a photothermal conversion efficiency approaching that of gold nanorods (η = 68 ± 6%), yet unlike nanorods, the synthesis of TRNs requires no cytotoxic compounds. Finally, we tested TRNs for the photothermal ablation of biofilms. Above Tt, NIR irradiation of TRNs resulted in a 10,000-fold improvement in killing efficiency compared to untreated controls (p < 0.0001). Below Tt, no enhanced antibiofilm effect was observed. In conclusion, engineering the interactions between proteins and nanoparticles enables the tunable control of TRNs, resulting in a novel antibiofilm nanomaterial with low cytotoxicity.

Swarna Bhasma Induces Antigen-Presenting Abilities of Macrophages and Helps Antigen Experienced CD4+ T Cells to Acquire Th1 Phenotypes Against Leishmania donovani Antigens.

In leishmaniasis, the protective immunity is largely mediated by proinflammatory cytokine producing abilities of T cells and an efficient parasite killing by phagocytic cells. Notwithstanding a substantial progress that has been made during last decades, the mechanisms or factors involved in establishing protective immunity against Leishmania are not identified. In ancient Indian literature, metallic "bhasma," particularly that of "swarna" or gold (fine gold particles), is indicated as one of the most prominent metal-based therapeutic medicine, which is known to impart protective and curative properties in various health issues. In this work, we elucidated the potential of swarna bhasma (SB) on the effector properties of phagocytes and antigen-activated CD4+ T cells in augmenting the immunogenicity of L. donovani antigens. The characterization of SB revealing its shape, size, composition, and measurement of cytotoxicity established the physiochemical potential for its utilization as an immunomodulator. The activation of macrophages with SB enhanced their capacity to produce nitric oxide and proinflammatory cytokines, which eventually resulted in reduced uptake of parasites and their proliferation in infected cells. Further, in Leishmania-infected animals, SB administration reduced the generation of IL-10, an anti-inflammatory cytokine, and enhanced pro-inflammatory cytokine generation by antigen activated CD4+ T cells with increased frequency of double (IFNγ+/TNFα+) and triple (IFNγ+TNFα+IL-2+) positive cells and abrogated disease pathogeneses at the early days of infection. Our results also suggested that cow-ghee (A2) emulsified preparation of SB, either alone or with yashtimadhu, a known natural immune modulator which enhances the SB's potential in enhancing the immunogenicity of parasitic antigens. These findings suggested a definite potential of SB in enhancing the effector functions of phagocytes and CD4+ T cells against L. donovani antigens. Therefore, more studies are needed to elucidate the mechanistic details of SB and its potential in enhancing vaccine-induced immunity.

Moringa oleifera leaves extract loaded gold nanoparticles offers a promising approach in protecting against experimental nephrotoxicity.

Cisplatin is one of the most important antitumor drugs, however; it has numerous adverse effects like nephrotoxicity which is considered one of cisplatin uses . The study was planned to evaluate the nephroprotective effect of M. oleifera leaves extract loaded gold nanoparticles (Au-NPs) against cisplatin-induced nephrotoxicity in rats. Initially, total phenolic contents (TPC) and the antioxidant activity of the M. oleifera leaves extract were evaluated and recorded 8.50 mg/g and 39.89 % respectively. After that, the dry leaves of M. oleifera were grinded into fine powder and extracted using water extraction system. Then, different volumes (0.5, 1 and 2 mL) of M. Oleifera were blended with constant volume of Au-NPs (1 mL). Both Au-NPs and M. oleifera extract loaded Au-NPs were investigated using transmission electron microscope (TEM) that illustrated the deposition of M. Oleifera onto Au-NPs. The experimental study was performed on seventy male albino rats alienated into seven groups. Group I healthy rats, group II injected with one dose of cisplatin (CisPt), groups from III to VII treated groups received CisPt then received M. Oleifera leaves extract alone and /or Au-NPs with different ratios and concentrations. After the experiment' time, serum urea and creatinine, kidney injury molecule-1 (KIM-1), advanced oxidation protein products (AOPP), monocyte chemoattractant protein-1 (MCP-1), tumor necrotic factor-α (TNF-α), and interleukin-6 (IL-6) were evaluated as markers of renal nephrotoxicity. The kidneys of rats were excised for malondialdehyde (MDA), nitric oxide (NO), and superoxide dismutase (SOD) assessments. Induction of CisPt showed a highly significant disturbance in oxidant/anti-oxidant balance and inducing inflammatory cascades supporting nephrotoxicity, while treatment with M. Oleifera leaves extract, Au-NPs, and the different concentrations of the extract loaded on Au-NPs had a crucial role in attenuating oxidative stress, enhancing antioxidant systems, and reducing inflammatory biomarkers, although the most significant results showed a powerful scavenging activity against nephrotoxicity induced by CisPt was obtained with M. Oleifera leaves extract loaded on Au-NPs with a concentration of 2:1 respectively.

Spatiotemporally controlled AuNPs@ZIF-8 based nanocarriers for synergistic photothermal/chemodynamic therapy.

High efficiency and spatio-temporal control remains a challenge for multi-modal synergistic cancer therapy. Herein, based on gold nanoparticles (AuNPs) and zeolite-like imidazole skeleton material (ZIF-8), a spatio-temporal controllable photothermal/ chemical dynamic/ chemotherapy three modal synergistic anti-tumor nano-carrier (HAZD) was developed. HAZD has a size of 128.75 ± 11.86 nm, a drug loading ratio of 21.5 ± 2.2 % and an encapsulation efficiency of 71.8 ± 1.7 %. Stability, acid responsive release character, outstanding catalytic ability to generate ROS, relatively high thermal conversion efficiency up to 62.38 % and spatio-temporal controllable abilities are also found within this nano-carrier. Furthermore, HAZD performed good antitumor ability in vivo with the comprehensive effects of photothermal/ chemical dynamic/ chemotherapy. The tumor growth inhibition value is 97.1 % within 12 days, indicating its great potential in multi-modal synergistic cancer therapy. STATEMENT OF SIGNIFICANCE: Cancer remains one of the major culprits that seriously harm human health currently. With the development of materials and nanotechnology, great improvements have been made in multimodal anti-tumor strategies. However, temporal- and spatial-controllable multi-modal synergistic nanocarriers are urgently awaited for efficient and low-toxicity tumor therapy. This article proposes a spatio-temporally controllable three-modal anti-tumor strategy and designs an anti-tumor drug delivery system based on gold nanoparticles (AuNPs) and zeolite-like imidazole skeleton material (ZIF-8), which shows acid-responsive release characteristics, catalytic ability to generate ROS, relatively high thermal conversion efficiency up to 62.38 %, as well as spatio-temporal controllable abilities. Moreover, it demonstrates outstanding anti-tumor ability, with a tumor growth inhibition value of 97.1 % within 12 days, revealing its significant potential for future personalized and precise anti-tumor treatments.

An amplified sonodynamic therapy by a nanohybrid of titanium dioxide-gold-polyethylene glycol-curcumin: HeLa cancer cells treatment in 2D monolayer and 3D spheroid models.

The utilization of ultrasound (US) to activate sonosensitizers for sonodynamic therapy (SDT) has faced challenges such as low activation efficiency and limited therapeutic outcomes, which have hampered its clinical applications. In this study, a nanohybrid of titanium dioxide-gold-polyethylene glycol-curcumin (TiO2-Au-PEG-Cur NH), as a novel US sensitizer, was synthesized, characterized, and applied for SDT of HeLa cancer cells in 2D monolayer model, and also a 3D spheroid model to bridge the gap between 2D cell culture and in vivo future studies. TiO2-Au-PEG-Cur NH contained TiO2 nanoparticles of 36 ± 11 nm in diameter, PEG-curcumin as a filler, and gold nanoparticles of 21 ± 7 nm in diameter with a high purity and a 35:17 of Ti:Au ratio (W/W), and it had a band gap of 2.4 eV, a zeta potential of -23 ± 7 mV, high stability upon US radiation cycles as well as one year storage. SDT of HeLa cells using TiO2-Au-PEG-Cur NH was investigated in the courses of cytotoxicity assessment in vitro, reactive oxygen species (ROS) generation capability, colony formation, cell migration, and the way to form spheroid. IC50 values of 122 and 38 µg mL-1 were obtained for TiO2-Au-PEG-Cur NH without and with US radiation, respectively. TiO2-Au-PEG-Cur NH not only exhibited an inherent capacity to generate ROS, but also represented an excellent therapeutic performance on the cancer cells through ROS generation and enhanced inhibitory effects on cell migration and spheroid formation.

Gold-Crowned Bismuth-Based Nanocomposites for Sonodynamic, Photothermal, and Chemotherapeutic Cancer Therapy.

Conventional inorganic semiconductor nanoparticles have emerged as photothermal agents in photothermal therapy and as sonosensitizers in sonodynamic therapy. However, their weak drug-loading capabilities and the deficient techniques for multifunctional inorganic nanoparticles limit their applications. A bismuth-based gold-crowned nanocomposite (BACN) was rationally designed and successfully synthesized and could then be used to prepare nanoplatforms with excellent biocompatibilities for synergistic therapy and real-time imaging. Because of the constituent gold nanoparticles and pyridine, the nanoplatforms functioned as drug delivery vehicles, ultrasonically activated sonosensitizers, and photothermal agents. The BACNs exhibited excellent photothermal conversion efficiency (79.1%) in the second near-infrared biowindow (1064 nm). Cellular and mouse experiments demonstrated that under laser and ultrasound irradiation bufalin-loaded BACNs significantly reduced cancer cell counts and completely eradicated tumors, along with great therapeutic biosafety and no discernible recurrence. Additionally, BACNs were also used as contrast agents in computed tomography-photoacoustic imaging. The versatile BACN nanoplatform with multitreatment effects and trimodal imaging properties shows immense potential as an antitumor nanotherapeutic system.

Polyphenolic Compounds Nanostructurated with Gold Nanoparticles Enhance Wound Repair.

Gold nanoparticles (AuNPs) have been used in a wide range of applications, conferring to bio-molecules diverse properties such as delivery, stabilization, and reduction of the adverse effects of drugs or plant extracts. Polyphenolic compounds from Bacopa procumbens (B. procumbens) (BP) can modulate proliferation, adhesion, migration, and cell differentiation, reducing the artificial scratch area in fibroblast cultures and promoting wound healing in an in vivo model. Here, chemically synthesized AuNPs conjugated with BP (AuNP-BP) were characterized using UV-Vis, ATR-FTIR, DLS, zeta-potential, and TEM analysis. The results showed an overlap of the FTIR spectra of the polyphenolic compounds from B. procumbens adhered to the surface of the AuNPs. UV-vis analysis indicated that the average size of the AuNP-BP was 28 nm, while DLS analysis showed a size of 44.58 nm and, by TEM, a size of 16.5 nm with an icosahedral morphology was observed. These measurements suggest an increase in the size of the nanoparticles after conjugation with BP, compared to the sizes of 9 nm, 44.51 nm, and 14.17 nm for the unconjugated AuNPs, respectively. Furthermore, the zeta potential of the AuNPs, which was originally -36.3 ± 12.3 mV shifted to -18.2 ± 7.02 mV after conjugation with BP, indicating improved stability of the nanoparticles. Enhancement of the wound healing effect was evaluated by morphometric, histochemical, and FTIR changes in a rat wound excision model. Results showed that the nanoconjugation process reduced the BP concentrations by 100-fold to have the same wound healing effect as BP alone. Besides, histological and FTIR spectroscopy analyses demonstrated that AuNP-BP treatment exhibited better macroscopical performance, showing a reduction in inflammatory cells and an increased synthesis and improved organization of collagen fibers.

Biological Synthesis, Characterization, and Therapeutic Potential of S. commune-Mediated Gold Nanoparticles.

Green-synthesized gold nanoparticles demonstrate several therapeutic benefits due to their safety, non-toxicity, accessibility, and ecological acceptance. In our study, gold nanoparticles (AuNPs) were created using an extracellular extract from the fungus Schizophyllum commune (S. commune). The reaction color was observed to be a reddish pink after a 24 h reaction, demonstrating the synthesis of the nanoparticles. The myco-produced nanoparticles were investigated using transmission electron microscopy (TEM), dynamic light scattering (DLS), and UV-visible spectroscopy. The TEM pictures depicted sphere-like shapes with sizes ranging from 60 and 120 nm, with an average diameter of 90 nm, which is in agreement with the DLS results. Furthermore, the efficiency of the AuNPs' antifungal and cytotoxic properties, as well as their production of intracellular ROS, was evaluated. Our findings showed that the AuNPs have strong antifungal effects against Trichoderma sp. and Aspergillus flavus at increasing doses. Additionally, the AuNPs established a dose-dependent activity against human alveolar basal epithelial cells with adenocarcinoma (A549), demonstrating the potency of synthesized AuNPs as a cytotoxic agent. After 4 h of incubation with AuNPs, a significant increase in intracellular ROS was observed in cancer cells. Therefore, these metallic AuNPs produced by fungus (S. commune) can be used as an effective antifungal, anticancer, and non-toxic immunomodulatory delivery agent.

Chitosan functionalized gold nanostars as a theranostic platform for intracellular microRNA detection and photothermal therapy.

The development of a theranostic platform that integrates both diagnostic and therapeutic capabilities is in great need for precise and personalized medicine. Here, we present a novel nanoplatform (AuNS@CS-hpDNA) formulated by chitosan functionalized gold nanostar composites and further complexed with fluorescent hairpin DNA (hpDNA) probes for tumor-related miRNA imaging and photothermal therapy (PTT). The optimized AuNS@CS-hpDNA nanoplatform mediated efficient hpDNA probe loading and intracellular delivery. Subsequently, the cytosol transfer of the hpDNA probe enabled specific hybridization using the targeted miRNA, which triggered the recovery of fluorescence for the precise detection of biomarker miR21 in living cells and realized the distinguishing cancer cell line MCF-7 and normal cells. Meanwhile, the AuNS@CS-hpDNA nanoplatform exhibited excellent photothermal conversion properties, which induced efficient cancer cell killing under laser irradiation. Thus, the developed AuNS@CS-hpDNA nanoplatform could simultaneously realize the precise detection of cancer cells and accurately initiate efficient PTT, which represents a promising strategy for precise cancer therapy.

Gold Nanorod/Titanium Dioxide Hybrid Nanoparticles for Plasmon-Enhanced Near-Infrared Photoproduction of Hydroxyl Radicals and Photodynamic Therapy.

Gold nanoparticles, such as nanorods (AuNRs), present exceptionally high absorption cross sections that can be tuned to the near-infrared (NIR), the optimal window for light penetration in biological tissues. This makes them valuable photosensitizers for the treatment of cancer using photothermal therapy, where absorbed light energy is converted into heat. In addition, there is a strong interest in using hot electron carriers generated in AuNRs by NIR irradiation to produce cytotoxic radical oxygen species in order to enhance the efficiency of the phototherapy. Here, we show that hybrid nanoparticles composed of AuNRs with TiO2 deposited at their extremities are efficient sensitizers to produce hydroxyl radical species under NIR irradiation. We attribute this phenomenon to the transfer of hot electrons generated from the plasmon excitation in AuNR to the TiO2 tips, followed by reduction of dioxygen. We then functionalize these hybrid AuNR/TiO2 nanoparticles with block poly(ethylene glycol)-phosphonate polymer ligands to stabilize them in a physiological medium. We finally demonstrate that the photodynamic effect induces cell death upon irradiation with a greater efficiency than the photothermal effect alone.

Synthesis and characterisation of gold nanoparticles from acacia leaf and to evaluate anticariogenic activity.

Objective: To synthesise the gold nanoparticles (AuNPs) using Acacia catechu through biogenic synthesis and evaluate their antimicrobial efficacy against S. mutans and E. coli in vitro. Methods: Green synthesised AuNPs were characterised using the ultraviolet-visible (UV-Vis) spectroscopy, and the size and shape of the synthesised nanoparticles were evaluated using the transmission electron microscopy (TEM). The antimicrobial efficacy of AuNPs (30/60/100 µl) against S. mutans/E. coli was evaluated on the Mueller-Hinton agar by measuring the zone of inhibition (ZOI) with ampicillin (15 µl) as a positive control. Results: The synthesised AuNPs were confirmed using the UV-Vis spectroscopy with peaks at 540 nm, and the size of the particle estimated using the TEM was between 5 and 15 nm. The antimicrobial efficacy of AuNPs was comparable to that of ampicillin against S. mutans/E. coli, but the difference was not significant. The antimicrobial effects increased in a dose-dependent fashion but were comparable across all concentrations and ampicillin. Conclusion: Green synthesised AuNPs exhibited significant antibacterial activity against S. mutans and E. coli at par with commercial ampicillin and demonstrated the potential towards anticariogenic agent for future use in dentistry.

Determination of anti-tuberculosis activity of biosynthesized gold nanocompounds against M. tuberculosis H37RV.

BACKGROUND: The biosynthesis of gold nanoparticles using medicinal plants as reducing and stabilizing agent for synthesis is an emerging area of research due to their cost effectiveness and further diversified applications in various fields. People with HIV are prone to these opportunistic infections like TB due to the immunocompromised condition. In the present study, the nanoparticles and nanoconjugates were screened for effective anti-mycobacterial efficiency against opportunistic infections. METHODS: Incidentally, the nanoparticles were biosynthesized using single plant extract. The biosynthesized nanoparticles were initially screened for effective anti-tuberculosis activity against Mycobacterium tuberculosis. Based on the effective antimicrobial activity, a nanoconjugate was biosynthesized combining three plant extracts for a cumulative activity. RESULTS: The biosynthesized gold nanoparticles and nanoconjugates showed MIC demonstrating for 99% inhibition and MIC99 was found to be 6.42 µg/ml. Among all the 15 nanoparticles tested, seven NPs showed exceptional anti-TB activities NP1, NP2, NP6, NP7, NP10, NP12 and NP15 and the other nanoparticles exhibited varying degrees of inhibition - anti-TB activities. In the 12 nanoconjugate tested, seven nanoconjugate demonstrated exceptional anti-TB activities such as NCC1, NCC2, NCC5, NCC6, NCV1, NCV6 and NCV4. CONCLUSION: The objective of the study was to identify the nanoparticles and nanoconjugates which demonstrated potential activity against M. tuberculosis so that a single nanoparticle or nanoconjugate can be targeted to treat patients with TB. Minimum Inhibitory Concentration (MIC) of the biosynthesized gold nanoparticles and nanoconjugates were determined against M. tuberculosis H37Rv.

Effect of gold nanoparticles distribution radius on photothermal therapy efficacy.

Lasers are used in various fields, however, in the medical field, they are mainly used for incision or chemotherapy. Photothermal therapy (PTT) is an anti-cancer treatment technique that uses lasers and the photothermal effect to increase the temperature of tumor tissue and induce its death. In this study, the therapeutic effect of PTT using gold nanoparticles as a photothermal converter was analyzed numerically for the occurrence of squamous cell carcinoma inside a skin section consisting four layers. Numerical modeling was implemented to calculate the temperature distribution inside the biological tissue while varying the distribution radius of gold nanoparticles in the tumor tissue, the number of injections, and the intensity of the irradiating laser. For the given situation, the optimal treatment effect was observed when the distribution radius ratio of the injected gold nanoparticles (GNPs) was 1, the number of injections was 7, and the intensity of the irradiated laser was 52 mW. Three apoptotic variables were used to quantitively evaluate the effect of PTT in each case and thus suggest the optimal treatment effect. However, although the temperature range at which apoptosis occurs is known, the maintenance of that temperature range is still under research and the temporal influence of apoptosis remains to be determined.