Special Issue "Synthesis, and Characterisation of Metallic and Non-Metallic Nanoparticle Systems for Use in Biomedical and Catalytic Applications"

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Catalytic Materials".

Deadline for manuscript submissions: closed (30 November 2020).

Special Issue Editor

Assoc. Prof. Dr. Michael R. Mucalo
E-Mail Website
Guest Editor
University of Waikato, Department of Chemistry, Hamilton, New Zealand
Interests: biomaterials; calcium phosphate chemistry; metal colloids; IR spectroelectrochemistry; pseudohalide-containing electrolytes; application of IR spectroscopy; drug delivery
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Special Issue Information

Dear Colleagues,

Research on metal nanoparticle systems is a very active and topical field in today’s research environment. The formation of metal nanoparticles and their characterization (usually under the subject heading of colloid science) have preoccupied scientists for over 160 years as a defined scientific discipline, since Michael Faraday demonstrated the existence (by accident) of gold colloids which are still on display in the Royal Institution of Great Britain (https://www.rigb.org/our-history/iconic-objects/iconic-objects-list/faraday-gold-colloids). Indeed, the fascination with colloidal matter has existed since ancient times, an example of this dating back to 1600, when the alchemist Paracelsus claimed that “aurum potabile” (drinkable gold) had amazing medicinal properties and the ability to cure all diseases. However, by the 18th century, the well-dispersed nature of these colloidal suspensions had already been identified by various individuals [1].

Faraday’s demonstration of the colloidal state in his red gold colloids led to more work by many other researchers in the late 19th and early 20th centuries. An excellent and vast summary of this historical colloid research has been provided by Harry Boyer Weiser in three volumes, which present the inorganic colloid chemistry of “The Colloidal Elements| (Volume 1), [1], “ The Hydrous Oxides and Hydroxides” (Volume 2) [2], and “The Colloidal Salts” (Volume 3) [3]. This series, especially Volume 1, describes fascinating and defining seminal research on a surprisingly wide range of metallic and non-metallic colloidal systems.

Following a lull in interest in these systems, a strongly renewed interest in metal colloid science area occurred in the late 20th century, persisting until now in the 21st century. “Nanotechnology” is the broader umbrella term  under which research into colloidal systems now falls along with many other genres of science which follow the nanotechnological theme. The use of the terms “nanoparticles” or “nanomaterials” has also entered the scientific parlance and has, it appears, overtaken the term “colloidal”. The invigoration of research in this area has come about because of the promise of the many diverse applications that such systems can potentially provide. One example is their use in biomedical applications, where metallic nanoparticles, bimetallic/alloy nanoparticles, metal oxide nanoparticles and magnetic nanoparticles are of use in bioimaging, biosensors, drug delivery to specific areas of the body, labelling of cells and gene delivery (amongst other areas) [4]. The potential uses of these nano-entities have even caught the fanciful and sensationalistic imagination of the film and television industry, which use the terms “nanobots” or “nanites” to refer to particles made of graphene of nanoscopic dimensions capable of curing diseases when inserted hypodermically into the body.  (https://en.wikipedia.org/wiki/Travelers_(TV_series).

Another very large area of research involving colloidal materials regards their use as heterogeneous nanocatalysts [5]. For such application, control of size, shape, particle morphology and compositions are key. It is also of interest to investigate suitable solid supports on which to immobilise such nanocrystals for catalytic purposes. Surface-Enhanced Raman Scattering (SERS), a phenomenon discovered in the 1970s, is a promising sensitive technique for the detection of a wide variety of species. The technique makes use of colloidal materials (especially silver, gold or copper) to construct SERS-active substrates. This is another very intensely researched area of colloid science, with the view to make a sensitive, robust and reproducible detection technique which has low limits of detection [6].

With all the research being carried out on nanoparticles notably in biomedical, food science and environment areas, their inherent safety of application has come under serious consideration.   Research into nanoparticles has also raised some  significant concerns about their overall “safety”, and this has stimulated discussion in this area [7].

Whatever their promise or their risks, researchers continue to make highly interesting advances in the fundamental science surrounding nanoparticles, continuously expanding the metals range being studied. It is, hence, the intention of this Special Issue to capture some of these most recent fundamental advances in the synthesis, characterisation and novel applications of metal nanoparticle systems. Many papers continue to be written about nanoparticles and colloids, especially on Pt, Pd and Au [8] nanoparticle systems, but less attention has been paid to some of the other precious metals such as Ru, Re, Rh, Ir and Os. This Special Issue welcomes original articles dealing with novel syntheses, characterisation and applications of colloidal dispersions of these metallic elements or bimetallic systems. In addition, this Special Issue also welcomes articles dealing with colloidal dispersions of non-metals such as S, Se and Te. The manuscripts detailing studies of the colloidally dispersed element under study are not restricted to the zero-oxidation state. As evident from Weiser’s volumes published in the 1930s [1–3], metal oxides and salts were studied in the colloidal state also, and this has continued to the present day; therefore, the scope of this Special Issue will also include them.  

As usual, any articles submitted to this Special Issue on nanoparticles will be subjected to robust peer review. Manuscripts dealing with the fundamental science of colloidal dispersions and their applications and reviews of nanoparticle systems can be submitted. We look forward to your contributions and hope to obtain papers on a broad selection of topics to make this a truly unique Special Issue.

  1. Weiser, H. B., Inorganic Colloid Chemistry, The Colloidal Elements. John Wiley and Sons: USA, 1933; Vol. 1.
  2. Weiser, H. B., Inorganic Colloid Chemistry, The Hydrous Oxides and Hydroxides. John Wiley and Sons: USA, 1935; Vol. 2.
  3. Weiser, H. B., Inorganic Colloid Chemistry, The Colloidal Salts. John Wiley and Sons: USA, 1938; Vol. 3.
  4. McNamara, K.; Tofail, S. A. M., Nanoparticles in biomedical applications. Advances in Physics: X 2017, 2, (1), 54-88.
  5. Na, K.; Zhang, Q.; Somorjai, G. A., Colloidal Metal Nanocatalysts: Synthesis, Characterization, and Catalytic Applications. Journal of Cluster Science 2014, 25, (1), 83-114.
  6. Mosier-Boss, A. P., Review of SERS Substrates for Chemical Sensing. Nanomaterials 2017, 7, (6).
  7. Naseer, B.; Srivastava, G.; Qadri Ovais, S.; Faridi Soban, A.; Islam Rayees, U.; Younis, K., Importance and health hazards of nanoparticles used in the food industry. In Nanotechnology Reviews, 2018; Vol. 7, p 623.
  8. Rodrigues, T. S.; Zhao, M.; Yang, T.-H.; Gilroy, K. D.; da Silva, A. G. M.; Camargo, P. H. C.; Xia, Y., Synthesis of Colloidal Metal Nanocrystals: A Comprehensive Review on the Reductants. Chemistry – A European Journal 2018, 24, (64), 16944-16963.
Assoc. Prof. Michael R. Mucalo
Guest Editor

Manuscript Submission Information

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  • colloids
  • nanoparticles
  • metals
  • non-metals
  • characterisation (IR, TEM, AFM, SERS)
  • lesser studied systems
  • novel synthetic methods
  • lesser studied metals
  • rhenium
  • rhodium
  • ruthenium
  • osmium
  • iridium
  • selenium
  • sulfur
  • tellurium
  • rare earth oxide colloids
  • radioactive colloids
  • bimetallic colloids
  • metal clusters
  • novel applications

Published Papers (2 papers)

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Structure and Properties of Biodegradable PLLA/ZnO Composite Membrane Produced via Electrospinning
Materials 2021, 14(1), 2; https://doi.org/10.3390/ma14010002 - 22 Dec 2020
Cited by 1 | Viewed by 700
These days, composite materials based on polymers and inorganic nanoparticles (NPs) are widely used in optoelectronics and biomedicine. In this work, composite membranes of polylactic acid and ZnO NPs containing 5–40 wt.% of the latter NPs were produced by means of electrospinning. For [...] Read more.
These days, composite materials based on polymers and inorganic nanoparticles (NPs) are widely used in optoelectronics and biomedicine. In this work, composite membranes of polylactic acid and ZnO NPs containing 5–40 wt.% of the latter NPs were produced by means of electrospinning. For the first time, polymer material loaded with up to 40 wt.% of ZnO NPs (produced via laser ablation in air and having non-modified surface) was used to prepare fiber-based composite membranes. The morphology, phase composition, mechanical, spectral and antibacterial properties of the membranes were tested by a set of analytical techniques including SEM, XRD, FTIR, UV-vis, and photoluminescence spectroscopy. Antibacterial activity of the materials was evaluated following standard procedures (ISO 20743:2013) and using S. aureus and E. coli bacteria. It is shown that incorporation of 5–10 wt.% of NPs led to improved mechanical properties of the composite membranes, while further increase of ZnO content up to 20 wt.% and above resulted in their noticeable deterioration. At the same time, the antibacterial properties of ZnO-rich membranes were more pronounced, which is explained by a larger number of surface-exposed ZnO NPs, in addition to those embedded into the bulk of fiber material. Full article
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A Review of The Lesser-Studied Microemulsion-Based Synthesis Methodologies Used for Preparing Nanoparticle Systems of The Noble Metals, Os, Re, Ir and Rh
Materials 2019, 12(12), 1896; https://doi.org/10.3390/ma12121896 - 12 Jun 2019
Cited by 9 | Viewed by 1908
This review focuses on the recent advances in the lesser-studied microemulsion synthesis methodologies of the following noble metal colloid systems (i.e., Os, Re, Ir, and Rh) using either a normal or reverse micelle templating system. The aim is to demonstrate the utility and [...] Read more.
This review focuses on the recent advances in the lesser-studied microemulsion synthesis methodologies of the following noble metal colloid systems (i.e., Os, Re, Ir, and Rh) using either a normal or reverse micelle templating system. The aim is to demonstrate the utility and potential of using this microemulsion-based approach to synthesize these noble metal nanoparticle systems. Firstly, some fundamentals and important factors of the microemulsion synthesis methodology are introduced. Afterward, a review of the investigations on the microemulsion syntheses of Os, Re, Ir, and Rh nanoparticle (NP) systems (in all forms, viz., metallic, oxide, mixed-metal, and discrete molecular complexes) is presented for work published in the last ten years. The chosen noble metals are traditionally very reactive in nanosized dimensions and have a strong tendency to aggregate when prepared via other methods. Also, the particle size and particle size distribution of these colloids can have a significant impact on their catalytic performance. It is shown that the microemulsion approach has the capability to better stabilize these metal colloids and can control the size of the synthesized NPs. This generally leads to smaller particles and higher catalytic activity when they are tested in applications. Full article
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