Nanomaterials

Research

21 pages, 3864 KiB

Open AccessEditor’s ChoiceArticle

In Situ Incorporation of Atomically Precise Au Nanoclusters within Zeolites for Ambient Temperature CO Oxidation

by Siriluck Tesana, John V. Kennedy, Alex C. K. Yip and Vladimir B. Golovko

Nanomaterials 2023, 13(24), 3120; https://0-doi-org.brum.beds.ac.uk/10.3390/nano13243120 - 12 Dec 2023

Viewed by 978

Preserving ultrasmall sizes of metal particles is a key challenge in the study of heterogeneous metal-based catalysis. Confining the ultrasmall metal clusters in a well-defined crystalline porous zeolite has emerged as a promising approach to stabilize these metal species. Successful encapsulation can be [...] Read more.

Preserving ultrasmall sizes of metal particles is a key challenge in the study of heterogeneous metal-based catalysis. Confining the ultrasmall metal clusters in a well-defined crystalline porous zeolite has emerged as a promising approach to stabilize these metal species. Successful encapsulation can be achieved by the addition of ligated metal complexes to zeolite synthesis gel before hydrothermal synthesis. However, controlling the metal particle size during post-reduction treatment remains a major challenge in this approach. Herein, an in situ incorporation strategy of pre-made atomically precise gold clusters within Na-LTA zeolite was established for the first time. With the assistance of mercaptosilane ligands, the gold clusters were successfully incorporated within the Na-LTA without premature precipitation and metal aggregation during the synthesis. We have demonstrated that the confinement of gold clusters within the zeolite framework offers high stability against sintering, leading to superior CO oxidation catalytic performance (up to 12 h at 30 °C, with a space velocity of 3000 mL g⁻¹ h⁻¹). Full article

(This article belongs to the Special Issue Synthesis and Applications of Gold Nanoparticles)

► Show Figures

Figure 1

13 pages, 3524 KiB

Open AccessArticle

Scanning Tunneling Microscopy Study of Lipoic Acid, Mannose, and cRGD@AuNPs Conjugates

by Andrés Rodríguez-Galván, Mitzi Reyes, Marisol Ávila-Cruz, Margarita Rivera and Vladimir A. Basiuk

Nanomaterials 2023, 13(18), 2596; https://0-doi-org.brum.beds.ac.uk/10.3390/nano13182596 - 20 Sep 2023

Viewed by 992

Abstract

The functionalization of AuNPs with different biological elements was achieved to investigate their possibility in biomedical applications such as drug delivery, vaccine development, sensing, and imaging. Biofunctionalized AuNPs are pursued for applications such as drug delivery, vaccine development, sensing, and imaging. In this [...] Read more.

The functionalization of AuNPs with different biological elements was achieved to investigate their possibility in biomedical applications such as drug delivery, vaccine development, sensing, and imaging. Biofunctionalized AuNPs are pursued for applications such as drug delivery, vaccine development, sensing, and imaging. In this study, AuNPs with diameters of 20 nm were functionalized with lipoic acid, mannose, or the cRGD peptide. By using UV-vis spectroscopy, Fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy, and scanning tunneling microscopy techniques, we showed that AuNPs can be functionalized by these biomolecules in a reliable way to obtain conjugates to explore potential biomedical applications. In particular, we demonstrate that the STM technique can be employed to analyze biofunctionalized AuNPs, and the obtained information can be valuable in the design of biomedical applications. Full article

(This article belongs to the Special Issue Synthesis and Applications of Gold Nanoparticles)

► Show Figures

Figure 1

13 pages, 2017 KiB

Open AccessArticle

Gold Nanorods as Radiopharmaceutical Carriers: Preparation and Preliminary Radiobiological In Vitro Tests

by Ludovica Binelli, Valentina Dini, Simone Amatori, Teresa Scotognella, Alessandro Giordano, Barbara De Berardis, Federica Bertelà, Chiara Battocchio, Giovanna Iucci, Ilaria Fratoddi, Antonella Cartoni and Iole Venditti

Nanomaterials 2023, 13(13), 1898; https://0-doi-org.brum.beds.ac.uk/10.3390/nano13131898 - 21 Jun 2023

Cited by 1 | Viewed by 1308

Abstract

Low-energy electrons (Auger electrons) can be produced via the interaction of photons with gold atoms in gold nanorods (AuNRs). These electrons are similar to those emitted during the decay of technetium-99m (^99mTc), a radioactive nuclide widely used for diagnostics in nuclear [...] Read more.

Low-energy electrons (Auger electrons) can be produced via the interaction of photons with gold atoms in gold nanorods (AuNRs). These electrons are similar to those emitted during the decay of technetium-99m (^99mTc), a radioactive nuclide widely used for diagnostics in nuclear medicine. Auger and internal conversion (IC) electron emitters appropriately targeted to the DNA of tumors cells may, therefore, represent a new radiotherapeutic approach. ^99mTc radiopharmaceuticals, which are used for diagnosis, could indeed be used in theragnostic fields when loaded on AuNRs and delivered to a tumor site. This work aims to provide a proof of concept (i) to evaluate AuNRs as carriers of ^99mTc-based radiopharmaceuticals, and (ii) to evaluate the efficacy of Auger electrons emitted by photon-irradiated AuNRs in inducing radio-induced damage in T98G cells, thus mimicking the effect of Auger electrons emitted during the decay of ^99mTc used in clinical settings. Data are presented on AuNRs’ chemical characterization (with an aspect ratio of 3.2 and Surface Plasmon Resonance bands at 520 and 680 nm) and the loading of pharmaceuticals (after ^99mTc decay) on their surface. Spectroscopic characterizations, such as UV-Vis and synchrotron radiation-induced X-ray photoelectron (SR-XPS) spectroscopies, were performed to investigate the drug–AuNR interaction. Finally, preliminary radiobiological data on cell killing with AuNRs are presented. Full article

(This article belongs to the Special Issue Synthesis and Applications of Gold Nanoparticles)

► Show Figures

Figure 1

12 pages, 5461 KiB

Open AccessArticle

Reduction of Nitroaromatics by Gold Nanoparticles on Porous Silicon Fabricated Using Metal-Assisted Chemical Etching

by Ling-Yi Liang, Yu-Han Kung, Vincent K. S. Hsiao and Chih-Chien Chu

Nanomaterials 2023, 13(11), 1805; https://0-doi-org.brum.beds.ac.uk/10.3390/nano13111805 - 5 Jun 2023

Cited by 3 | Viewed by 1200

Abstract

In this study, we investigated the use of porous silicon (PSi) fabricated using metal-assisted chemical etching (MACE) as a substrate for the deposition of Au nanoparticles (NPs) for the reduction of nitroaromatic compounds. PSi provides a high surface area for the deposition of [...] Read more.

In this study, we investigated the use of porous silicon (PSi) fabricated using metal-assisted chemical etching (MACE) as a substrate for the deposition of Au nanoparticles (NPs) for the reduction of nitroaromatic compounds. PSi provides a high surface area for the deposition of Au NPs, and MACE allows for the fabrication of a well-defined porous structure in a single step. We used the reduction of p-nitroaniline as a model reaction to evaluate the catalytic activity of Au NPs on PSi. The results indicate that the Au NPs on the PSi exhibited excellent catalytic activity, which was affected by the etching time. Overall, our results highlighted the potential of PSi fabricated using MACE as a substrate for the deposition of metal NPs for catalytic applications. Full article

(This article belongs to the Special Issue Synthesis and Applications of Gold Nanoparticles)

► Show Figures

Figure 1

11 pages, 3015 KiB

Open AccessArticle

Synthesis of Metal/SU-8 Nanocomposites through Photoreduction on SU-8 Substrates

by Yan-Jun Huang, Wen-Huei Chang, Yi-Jui Chen and Chun-Hung Lin

Nanomaterials 2023, 13(11), 1784; https://0-doi-org.brum.beds.ac.uk/10.3390/nano13111784 - 1 Jun 2023

Viewed by 1360

Abstract

The paper presents a simple, fast, and cost-effective method for creating metal/SU-8 nanocomposites by applying a metal precursor drop onto the surface or nanostructure of SU-8 and exposing it to UV light. No pre-mixing of the metal precursor with the SU-8 polymer or [...] Read more.

The paper presents a simple, fast, and cost-effective method for creating metal/SU-8 nanocomposites by applying a metal precursor drop onto the surface or nanostructure of SU-8 and exposing it to UV light. No pre-mixing of the metal precursor with the SU-8 polymer or pre-synthesis of metal nanoparticles is required. A TEM analysis was conducted to confirm the composition and depth distribution of the silver nanoparticles, which penetrate the SU-8 film and uniformly form the Ag/SU-8 nanocomposites. The antibacterial properties of the nanocomposites were evaluated. Moreover, a composite surface with a top layer of gold nanodisks and a bottom layer of Ag/SU-8 nanocomposites was produced using the same photoreduction process with gold and silver precursors, respectively. The reduction parameters can be manipulated to customize the color and spectrum of various composite surfaces. Full article

(This article belongs to the Special Issue Synthesis and Applications of Gold Nanoparticles)

► Show Figures

Figure 1

14 pages, 5646 KiB

Open AccessArticle

Nano-Conversion of Ineffective Cephalosporins into Potent One against Resistant Clinical Uro-Pathogens via Gold Nanoparticles

by Syed Mohd Danish Rizvi, Talib Hussain, Farhan Alshammari, Hana Sonbol, Nabeel Ahmad, Syed Shah Mohammed Faiyaz, Mohammad Amjad Kamal, El-Sayed Khafagy, Afrasim Moin and Amr Selim Abu Lila

Nanomaterials 2023, 13(3), 475; https://0-doi-org.brum.beds.ac.uk/10.3390/nano13030475 - 24 Jan 2023

Cited by 7 | Viewed by 1827

Abstract

Infections caused by resistant bacterial pathogens have increased the complications of clinicians worldwide. The quest for effective antibacterial agents against resistant pathogens has prompted researchers to develop new classes of antibiotics. Unfortunately, pathogens have acted more smartly by developing resistance to even the [...] Read more.

Infections caused by resistant bacterial pathogens have increased the complications of clinicians worldwide. The quest for effective antibacterial agents against resistant pathogens has prompted researchers to develop new classes of antibiotics. Unfortunately, pathogens have acted more smartly by developing resistance to even the newest class of antibiotics with time. The culture sensitivity analysis of the clinical samples revealed that pathogens are gaining resistance toward the new generations of cephalosporins at a very fast rate globally. The current study developed gold nanoparticles (AuNPs) that could efficiently deliver the 2nd (cefotetan-CT) and 3rd (cefixime-CX) generation cephalosporins to resistant clinical pathogens. In fact, both CT and CX were used to reduce and stabilize AuNPs by applying a one-pot synthesis approach, and their characterization was performed via spectrophotometry, dynamic light scattering and electron microscopy. Moreover, the synthesized AuNPs were tested against uro-pathogenic resistant clinical strains of Escherichia coli and Klebsiella pneumoniae. CT-AuNPs characteristic SPR peak was observed at 542 nm, and CX-AuNPs showed the same at 522 nm. The stability measurement showed ζ potential as −24.9 mV and −25.2 mV for CT-AuNPs and CX-AuNPs, respectively. Scanning electron microscopy revealed the spherical shape of both the AuNPs, whereas, the size by transmission electron microscopy for CT-AuNPs and CX-AuNPs were estimated to be 45 ± 19 nm and 35 ± 17 nm, respectively. Importantly, once loaded onto AuNPs, both the cephalosporin antibiotics become extremely potent against the resistant strains of E. coli and K. pneumoniae with MIC₅₀ in the range of 0.5 to 0.8 μg/mL. The findings propose that old-generation unresponsive antibiotics could be revived into potent nano-antibiotics via AuNPs. Thus, investing efforts, intellect, time and funds for a nano-antibiotic strategy might be a better approach to overcome resistance than investing the same in the development of newer antibiotic molecule(s). Full article

(This article belongs to the Special Issue Synthesis and Applications of Gold Nanoparticles)

► Show Figures

Figure 1

18 pages, 2488 KiB

Open AccessArticle

Boosted Radiation Bystander Effect of PSMA-Targeted Gold Nanoparticles in Prostate Cancer Radiosensitization

by Daiki Hara, Wensi Tao, Ryder M. Schmidt, Yu-Ping Yang, Sylvia Daunert, Nesrin Dogan, John Chetley Ford, Alan Pollack and Junwei Shi

Nanomaterials 2022, 12(24), 4440; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12244440 - 14 Dec 2022

Cited by 4 | Viewed by 1893

Abstract

Metal nanoparticles are effective radiosensitizers that locally enhance radiation doses in targeted cancer cells. Compared with other metal nanoparticles, gold nanoparticles (GNPs) exhibit high biocompatibility, low toxicity, and they increase secondary electron scatter. Herein, we investigated the effects of active-targeting GNPs on the [...] Read more.

Metal nanoparticles are effective radiosensitizers that locally enhance radiation doses in targeted cancer cells. Compared with other metal nanoparticles, gold nanoparticles (GNPs) exhibit high biocompatibility, low toxicity, and they increase secondary electron scatter. Herein, we investigated the effects of active-targeting GNPs on the radiation-induced bystander effect (RIBE) in prostate cancer cells. The impact of GNPs on the RIBE presents implications for secondary cancers or spatially fractionated radiotherapy treatments. Anti-prostate-specific membrane antigen (PSMA) antibodies were conjugated with PEGylated GNPs through EDC–NHS chemistry. The media transfer technique was performed to induce the RIBE on the non-irradiated bystander cells. This study focused on the LNCaP cell line, because it can model a wide range of stages relating to prostate cancer progression, including the transition from androgen dependence to castration resistance and bone metastasis. First, LNCaP cells were pretreated with phosphate buffered saline (PBS) or PSMA-targeted GNPs (PGNPs) for 24 h and irradiated with 160 kVp X-rays (0–8 Gy). Following that, the collected culture media were filtered (sterile 0.45 µm polyethersulfone) in order to acquire PBS- and PGNP- conditioned media (CM). Then, PBS- and PGNP-CM were transferred to the bystander cells that were loaded with/without PGNPs. MTT, γ-H2AX, clonogenic assays and reactive oxygen species assessments were performed to compare RIBE responses under different treatments. Compared with 2 Gy-PBS-CM, 8 Gy-PBS-CM demonstrated a much higher RIBE response, thus validating the dose dependence of RIBE in LNCaP cells. Compared with PBS-CM, PGNP-CM exhibited lower cell viability, higher DNA damage, and a smaller survival fraction. In the presence of PBS-CM, bystander cells loaded with PGNPs showed increased cell death compared with cells that did not have PGNPs. These results demonstrate the PGNP-boosted expression and sensitivity of RIBE in prostate cancer cells. Full article

(This article belongs to the Special Issue Synthesis and Applications of Gold Nanoparticles)

► Show Figures

Figure 1

14 pages, 1702 KiB

Open AccessArticle

Mesenchymal Stem Cell-Mediated Deep Tumor Delivery of Gold Nanorod for Photothermal Therapy

by Wan Su Yun, Man Kyu Shim, Seungho Lim, Sukyung Song, Jinseong Kim, Suah Yang, Hee Sook Hwang, Mi Ra Kim, Hong Yeol Yoon, Dong-Kwon Lim, In-Cheol Sun and Kwangmeyung Kim

Nanomaterials 2022, 12(19), 3410; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12193410 - 28 Sep 2022

Cited by 5 | Viewed by 2180

Abstract

Gold nanoparticles (AuNPs) with various sizes and morphologies have been extensively investigated for effective photothermal therapy (PTT) against multiple cancer types. However, a highly dynamic and complex tumor microenvironment (TME) considerably reduces the efficacy of PTT by limiting deep tumor penetration of AuNPs. [...] Read more.

Gold nanoparticles (AuNPs) with various sizes and morphologies have been extensively investigated for effective photothermal therapy (PTT) against multiple cancer types. However, a highly dynamic and complex tumor microenvironment (TME) considerably reduces the efficacy of PTT by limiting deep tumor penetration of AuNPs. Herein, we propose a mesenchymal stem cell (MSC)-mediated deep tumor delivery of gold nanorod (AuNR) for a potent PTT. First, MSCs are treated with tetraacylated N-azidomannosamine (Ac₄ManNAz) to introduce modifiable azide (N₃) groups on the cell surface via metabolic glycoengineering. Then, AuNRs modified with bio-orthogonal click molecules of bicyclo[6.1.0]nonyne (AuNR@BCN) are chemically conjugated to the N₃ groups on the MSC surface by copper-free click chemistry reaction, resulting in AuNR@MSCs. In cultured MSCs, the appropriate condition to incorporate the AuNR into the MSCs is optimized; in addition, the photothermal efficiency of AuNR-MSCs under light irradiation are assessed, showing efficient heat generation in vitro. In colon tumor-bearing mice, intravenously injected AuNR@MSCs efficiently accumulate within the tumor tissues by allowing deep tissue penetration owing to the tumor homing effect by natural tumor tropism of AuNR@MSCs. Upon localized light irradiation, the AuNR@MSCs significantly inhibit colon tumor growth by the enhanced photothermal effect compared to conventional AuNRs. Collectively, this study shows a promising approach of MSCs-mediated deep tumor delivery of AuNR for effective PTT. Full article

(This article belongs to the Special Issue Synthesis and Applications of Gold Nanoparticles)

► Show Figures

Figure 1

13 pages, 2913 KiB

Open AccessArticle

Magnetic-Core–Shell–Satellite Fe₃O₄-Au@Ag@(Au@Ag) Nanocomposites for Determination of Trace Bisphenol A Based on Surface-Enhanced Resonance Raman Scattering (SERRS)

by Jie Huang, Tianxiang Zhou, Wenshi Zhao, Min Zhang, Zhibo Zhang, Wangsheng Lai, Naveen Reddy Kadasala, Huilian Liu and Yang Liu

Nanomaterials 2022, 12(19), 3322; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12193322 - 24 Sep 2022

Cited by 5 | Viewed by 1771

Abstract

As a typical representative of endocrine-disrupting chemicals (EDCs), bisphenol A (BPA) is a common persistent organic pollutant in the environment that can induce various diseases even at low concentrations. Herein, the magnetic Fe₃O₄-Au@Ag@(Au@Ag) nanocomposites (CSSN NCs) have been prepared [...] Read more.

As a typical representative of endocrine-disrupting chemicals (EDCs), bisphenol A (BPA) is a common persistent organic pollutant in the environment that can induce various diseases even at low concentrations. Herein, the magnetic Fe₃O₄-Au@Ag@(Au@Ag) nanocomposites (CSSN NCs) have been prepared by self-assembly method and applied for ultra-sensitive surface-enhanced resonance Raman scattering (SERRS) detection of BPA. A simple and rapid coupling reaction of Pauly’s reagents and BPA not only solved the problem of poor affinity between BPA and noble metals, but also provided the SERRS activity of BPA azo products. The distribution of hot spots and the influence of incremental introduction of noble metals on the performance of SERRS were analyzed by a finite-difference time-domain (FDTD) algorithm. The abundance of hot spots generated by core–shell–satellite structure and outstanding SERRS performance of Au@Ag nanocrystals were responsible for excellent SERRS sensitivity of CSSN NCs in the results. The limit of detection (LOD) of CSSN NCs for BPA azo products was as low as 10⁻¹⁰ M. In addition, the saturation magnetization (Ms) value of CSSN NCs was 53.6 emu·g⁻¹, which could be rapidly enriched and collected under the condition of external magnetic field. These magnetic core–shell–satellite NCs provide inspiration idea for the tailored design of ultra-sensitive SERRS substrates, and thus exhibit limitless application prospects in terms of pollutant detection, environmental monitoring, and food safety. Full article

(This article belongs to the Special Issue Synthesis and Applications of Gold Nanoparticles)

► Show Figures

Graphical abstract

17 pages, 4800 KiB

Open AccessArticle

Highly Stable, Graphene-Wrapped, Petal-like, Gap-Enhanced Raman Tags

by Ming Chen, Bin Wang, Jingfan Wang, Hongliang Liu, Zhixiang Chen, Xiaoxuan Xu and Xing Zhao

Nanomaterials 2022, 12(10), 1626; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12101626 - 10 May 2022

Cited by 3 | Viewed by 1778

Abstract

Gap-enhanced Raman tags (GERTs) were widely used in cell or biological tissue imaging due to their narrow spectral linewidth, weak photobleaching effect, and low biological matrix interference. Here, we reported a new kind of graphene-wrapped, petal-like, gap-enhanced Raman tags (GP-GERTs). The 4-Nitrobenzenethiol (4-NBT) [...] Read more.

Gap-enhanced Raman tags (GERTs) were widely used in cell or biological tissue imaging due to their narrow spectral linewidth, weak photobleaching effect, and low biological matrix interference. Here, we reported a new kind of graphene-wrapped, petal-like, gap-enhanced Raman tags (GP-GERTs). The 4-Nitrobenzenethiol (4-NBT) Raman reporters were embedded in the petal-like nanogap, and graphene was wrapped on the surface of the petal-like, gap-enhanced Raman tags. Finite-difference time-domain (FDTD) simulations and Raman experimental studies jointly reveal the Raman enhancement mechanism of graphene. The SERS enhancement of GP-GERTs is jointly determined by the petal-like “interstitial hotspots” and electron transfer between graphene and 4-NBT molecules, and the total Raman enhancement factor (EF) can reach 10¹⁰. Mesoporous silica was grown on the surface of GP-GERTs by tetraethyl orthosilicate hydrolysis to obtain Raman tags of MS-GP-GERTs. Raman tag stability experiments showed that: MS-GP-GERTs not only can maintain the signal stability in aqueous solutions of different pH values (from 3 to 12) and simulated the physiological environment (up to 72 h), but it can also stably enhance the signal of different Raman molecules. These highly stable, high-signal-intensity nanotags show great potential for SERS-based bioimaging and multicolor imaging. Full article

(This article belongs to the Special Issue Synthesis and Applications of Gold Nanoparticles)

► Show Figures

Figure 1

17 pages, 3572 KiB

Open AccessArticle

Near-Infrared Light-Triggered Nitric Oxide Nanogenerators for NO-Photothermal Synergistic Cancer Therapy

by Weiwei Liu, Farouk Semcheddine, Zengchao Guo, Hui Jiang and Xuemei Wang

Nanomaterials 2022, 12(8), 1348; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12081348 - 14 Apr 2022

Cited by 10 | Viewed by 2595

Abstract

Cancer is still one of the major health issues faced by human beings today. Various nanomaterials have been designed to treat tumors and have made great progress. Herein, we used amino-functionalized metal organic framework (UiO-66-NH₂) as superior templates and successfully synthesized [...] Read more.

Cancer is still one of the major health issues faced by human beings today. Various nanomaterials have been designed to treat tumors and have made great progress. Herein, we used amino-functionalized metal organic framework (UiO-66-NH₂) as superior templates and successfully synthesized the UiO-66-NH₂@Au_shell composite nanoparticles (UA) with high loading capacity and excellent photothermal properties through a simple and gentle method. In addition, due to the rich pore structure and excellent biocompatibility of the as-prepared composite nanoparticles, the hydrophobic NO donor BNN6 (N,N′-Di-sec-butyl-N,N′-dinitroso-1, 4-phenylenediamine) molecule was efficiently delivered. Based on the phenomenon where BNN6 molecules can decompose and release NO at high temperature, when UiO-66-NH₂@Au_shell-BNN6 composite nanoparticles (UA-BNN6) entered tumor cells and were irradiated by NIR, the porous gold nanoshells on the surface of composite nanoparticles induced an increase in temperature through the photothermal conversion process and promoted the decomposition of BNN6 molecules, releasing high concentration of NO, thus efficiently killing HeLa cells through the synergistic effect of NO-photothermal therapy. This effective, precise and safe treatment strategy controlled by NIR laser irradiation represents a promising alternative in the field of cancer treatment. Full article

(This article belongs to the Special Issue Synthesis and Applications of Gold Nanoparticles)

► Show Figures

Figure 1

22 pages, 3816 KiB

Open AccessArticle

Efficacy of Gold Nanoparticles against Drug-Resistant Nosocomial Fungal Pathogens and Their Extracellular Enzymes: Resistance Profiling towards Established Antifungal Agents

by Abobakr Almansob, Ali H. Bahkali and Fuad Ameen

Nanomaterials 2022, 12(5), 814; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12050814 - 28 Feb 2022

Cited by 41 | Viewed by 2224

Abstract

Drug resistance of filamentous fungi to the commonly used antifungal agents is a major concern in medicine. Therefore, an effective approach to treat several opportunistic fungal infections is the need of the hour. Mentha piperita is used in home remedies to treat different [...] Read more.

Drug resistance of filamentous fungi to the commonly used antifungal agents is a major concern in medicine. Therefore, an effective approach to treat several opportunistic fungal infections is the need of the hour. Mentha piperita is used in home remedies to treat different disorders. Isolates of fungi were taken from hospitals in Riyadh, Saudi Arabia, and identified using molecular tools. Amphotericin B, Voriconazole, and Micafungin were applied to screen the resistance of these isolates using both disc and broth microdilution techniques. An aqueous extract of Mentha piperita was utilized to synthesize AuNPs and the nanoparticles were characterized using UV-Vis, FTIR, TEM, EDAX, and XRD. The AuNPs were tested for antifungal activity against the nosocomial fungal pathogens and the activity of extracellular enzymes of such pathogens were analyzed after treatment with AuNPs. We conclude that AuNPs synthesized using Mentha piperita do not possess especially effective antifungal properties against multi-drug resistant Aspergillus species. Five out of eighteen isolates were inhibited by AuNPs. When inhibition was observed, significant alterations in the activity profile of extracellular enzymes of the nosocomial fungi were observed. Full article

(This article belongs to the Special Issue Synthesis and Applications of Gold Nanoparticles)

► Show Figures

Figure 1

11 pages, 1588 KiB

Open AccessArticle

Tetrahedral DNA Framework-Programmed Electrochemical Biosenors with Gold Nanoparticles for Ultrasensitive Cell-Free DNA Detection

by Chenguang Wang, Wei Wang, Yi Xu, Xiaoshuang Zhao, Shuainan Li, Qiuling Qian and Xianqiang Mi

Nanomaterials 2022, 12(4), 666; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12040666 - 16 Feb 2022

Cited by 9 | Viewed by 2618

Abstract

Tumor-associated cell-free DNA (cfDNA) is a dynamic biomarker for genetic analysis, early diagnosis and clinical treatment of cancers. However, its detection has limitations because of its low abundance in blood or other complex bodily fluids. Herein, we developed an ultrasensitive cfDNA electrochemical biosensor [...] Read more.

Tumor-associated cell-free DNA (cfDNA) is a dynamic biomarker for genetic analysis, early diagnosis and clinical treatment of cancers. However, its detection has limitations because of its low abundance in blood or other complex bodily fluids. Herein, we developed an ultrasensitive cfDNA electrochemical biosensor (E-cfDNA sensor) based on tetrahedral DNA framework (TDF)-modified gold nanoparticles (Au NPs) with an interface for cfDNA detection. By accurately controlling the numbers of base pairs on each DNA framework, three types of TDFs were programmed: 26 base pairs of TDF; 17 base pairs of TDF; and 7 base pairs of TDF (TDF-26, TDF-16 and TDF-7, respectively). We also combined the TDF with hybridization chain reaction (HCR) to achieve signal amplification. Under optimal conditions, we detected the breast cancer susceptibility gene 1 (BRCA-1), a representative cfDNA closely related to breast cancer. An ultra-low detection limit of 1 aM with a linear range from 1 aM to 1 pM by TDF-26 was obtained, which was superior to the existing methods. Each type of TDF has excellent discrimination ability, which can distinguish single mismatch. More significantly, we also detected BRCA-1 in mimic serum samples, demonstrating that the E-cfDNA sensor has potential use in clinical research. Full article

(This article belongs to the Special Issue Synthesis and Applications of Gold Nanoparticles)

► Show Figures

Figure 1

14 pages, 5534 KiB

Open AccessArticle

Green Synthesis of Gold Nanoparticles Using Upland Cress and Their Biochemical Characterization and Assessment

by Noah Hutchinson, Yuelin Wu, Yale Wang, Muskan Kanungo, Anna DeBruine, Emma Kroll, De’Jorra Gilmore, Zachary Eckrose, Stephanie Gaston, Phoebe Matel, Matey Kaltchev, Anne-Marie Nickel, Subha Kumpaty, Xiaolin Hua and Wujie Zhang

Nanomaterials 2022, 12(1), 28; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12010028 - 23 Dec 2021

Cited by 13 | Viewed by 4920

Abstract

This research focuses on the plant-mediated green synthesis process to produce gold nanoparticles (Au NPs) using upland cress (Barbarea verna), as various biomolecules within the upland cress act as both reducing and capping agents. The synthesized gold nanoparticles were thoroughly characterized using UV-vis [...] Read more.

This research focuses on the plant-mediated green synthesis process to produce gold nanoparticles (Au NPs) using upland cress (Barbarea verna), as various biomolecules within the upland cress act as both reducing and capping agents. The synthesized gold nanoparticles were thoroughly characterized using UV-vis spectroscopy, surface charge (zeta potential) analysis, scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX), atomic force microscopy (AFM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray diffraction (XRD). The results indicated the synthesized Au NPs are spherical and well-dispersed with an average diameter ~11 nm and a characteristic absorbance peak at ~529 nm. EDX results showed an 11.13% gold content. Colloidal Au NP stability was confirmed with a zeta potential (ζ) value of −36.8 mV. X-ray diffraction analysis verified the production of crystalline face-centered cubic gold. Moreover, the antimicrobial activity of the Au NPs was evaluated using Gram-negative Escherichiacoli and Gram-positive Bacillus megaterium. Results demonstrated concentration-dependent antimicrobial properties. Lastly, applications of the Au NPs in catalysis and biomedicine were evaluated. The catalytic activity of Au NPs was demonstrated through the conversion of 4-nitrophenol to 4-aminophenol which followed first-order kinetics. Cellular uptake and cytotoxicity were evaluated using both BMSCs (stem) and HeLa (cancer) cells and the results were cell type dependent. The synthesized Au NPs show great potential for various applications such as catalysis, pharmaceutics, and biomedicine. Full article

(This article belongs to the Special Issue Synthesis and Applications of Gold Nanoparticles)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Synthesis and Applications of Gold Nanoparticles

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (14 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI