SERS Research Applied to Polymer Based Nanocomposites

Polymer based nanocomposites containing metal nanoparticles (e.g. Au, Ag) have gained increased attention as a new class of SERS (Surface Enhanced Raman Scattering) substrates for analytical platforms. On the other hand, the application of SERS using such platforms can also provide new insights on the properties of composite materials. In this chapter, we review recent research on the development of SERS substrates based on polymer nanocomposites and their applications in different fields. The fundamentals of SERS are briefly approached and subsequently there is a reference to the strategies of preparation of polymer based nanocomposites. Here the main focus is on SERS studies that have used a diversity of polymer based nanocomposites, highlighting certain properties of the materials that are relevant for the envisaged functionalities. A final section is devoted to the joint use of Raman imaging and SERS in nanocomposites development, a topic that presents a great potential still to be explored as shown by the recent research in this field

Advances in optical sensors for persistent organic pollutant environmental monitoring

Optical chemical sensors are widely applied in many fields of modern analytical practice, due to their simplicity in preparation and signal acquisition, low costs, and fast response time. Moreover, the construction of most modern optical sensors requires neither wire connections with the detector nor sophisticated and energy-consuming hardware, enabling wireless sensor development for a fast, in-field and online analysis. In this review, the last five years of progress (from 2017 to 2021) in the field of optical chemical sensors development for persistent organic pollutants (POPs) is provided. The operating mechanisms, the transduction principles and the types of sensing materials employed in single selective optical sensors and in multisensory systems are reviewed. The selected examples of optical sensors applications are reported to demonstrate the benefits and drawbacks of optical chemical sensor use for POPs assessment

Sensing at nanostructures for agri-food and enviromental applications

With a predicted population increase of 2.3 billion people, by 2050, agricultural productivity must be vastly improved and made sustainable. Globally, agriculture must deliver a 60% increase in food production to cope with the population demand. Moreover, this needs to be achieved against a changing climate, an exploitation of natural resources, and growing water and land scarcities. New digital technologies can optimise production efficiency and ensure food security and safety while also minimising waste within the production systems and the supply chain. To this end, new sensor technologies are being developed for applications in animal health diagnostics and environmental issues related to the global population, such as food & crop protection, pathogen and toxin detection, and environmental remediation. In this thesis, two new nanosensing diagnostic devices are developed and presented; surface enhanced Raman sensing and electrochemical sensing. Surface-enhanced Raman spectroscopy (SERS) substrates were fabricated by templating a flexible thermoplastic polymer against an aluminium drinks can followed by coating with a silver film, to produce a rough nanostructured metallic surface. SERS is used for both qualitative (molecular fingerprint) and quantitative detection of dye molecules and food toxins. In addition, the SERS technique is also applied in combination with nanoelectrochemical square wave voltammetry to detect nano-concentrations of neonicotinoid pesticides. The enhanced sensitivity and minimum sample preparation requirements provide tremendous opportunities for food safety and security sectors. An impedimetric immunosensor device (with a micro SD style pin-out) was also developed for the serological diagnosis of viruses and antibodies associated with bovine respiratory disease and bovine liver fluke. The silicon chip devices consist of six on-chip nanoband electrodes which can be independently modified with a polymer layer for covalent immobilisation of capture and target biomolecules. This electrochemical biosensor technology provides label-free and cost-efficient sensing capability in a compact size, and demonstrates the potential development of immunoassay-based point-of-use devices for on-farm diagnosis or therapeutic monitoring in animal health applications

Advances in the development of innovative sensor platforms for field analysis

none8noSustainable growth, environmental preservation, and improvement of life quality are strategic fields of worldwide interest and cornerstones of international policies. Humanity health and prosperity are closely related to our present choices on sustainable development. The main sources of pollution concern industry, including mining, chemical companies, and refineries, wastewater treatment; and consumers themselves. In order to guide and evaluate the eects of environmental policies, diuse monitoring campaigns and detailed (big) data analyses are needed. In this respect, the development and availability of innovative sensor platforms for field analysis and remote sensing are of crucial relevance. In this review, we provide an overview of the area, analyzing the major needs, available technologies, novel approaches, and perspectives. Among environmental pollutants that threaten the biosphere, we focus on inorganic and organic contaminants, which aect air and water quality. We describe the technologies for their assessment in the environment and then draw some conclusions and mention future perspectives opened by the integration of sensing technologies with robotics and the Internet of Things. Without the ambition to be exhaustive in such a rapidly growing field, this review is intended as a support for researchers and stakeholders looking for current, state-of-the-art, and key enabling technologies for environmental monitoring.openRizzato S.; Leo A.; Monteduro Anna Grazia; Chiriaco Maria Serena; Primiceri E.; Sirsi F.; Milone A.; Maruccio G.Rizzato, S.; Leo, A.; Monteduro, ANNA GRAZIA; Chiriaco', MARIA SERENA; Primiceri, E.; Sirsi, F.; Milone, A.; Maruccio, G

Latest Advances in Nanoplasmonics and Use of New Tools for Plasmonic Characterization

Nanoplasmonics is an area that uses light to couple electrons in metals, and can break the diffraction limit for light confinement into subwavelength zones, allowing for strong field enhancements. In the last two decades, there has been a resurgence of this research topic and its applications. Thus, this Special Issue presents a collection of articles and reviews by international researchers and is devoted to the recent advances in and insights into this research topic, including plasmonic devices, plasmonic biosensing, plasmonic photocatalysis, plasmonic photovoltaics, surface-enhanced Raman scattering, and surface plasmon resonance spectroscopy

Transparent polymer-based SERS substrates templated by a soda can

This paper demonstrates the reproducible fabrication of transparent Surface Enhanced Raman Scattering (SERS) substrates, fabricated by employing an aluminium soda can to template nanostructures on a flexible thermoplastic polymer surface, followed by deposition of a silver over layer. Electron microscopy and finite element modelling simulations strongly suggested the SERS response arose at regions of high electromagnetic field strength occurring between metallic clusters following illumination by monochromatic radiation. The sensors exhibited rapid, quantitative and high sensitivity, for example, 5 × 10−10 M (204 pg/mL) crystal violet detection in 10 min using a simple drop and dry method. We also show detection of glucose employing a chemically modified silver surface bearing a pre-deposited SAM layer. Furthermore, the transparent substrates permitted back excitation and collection through the substrate with corresponding spectra exhibiting clear and well-defined spectral SERS peaks. Finally, we present the detection of trace amounts of melamine in complex media solution (milk and infant formula). We benchmark the sensor performance using commercial analytical instrumentation (MS-MS) and show comparable sensitivity between the SERS substrates and MS-MS

Precision Target Guide Strategy for Applying SERS into Environmental Monitoring

Surface enhanced Raman spectroscopy (SERS) is a promising analytical technique that exhibits various applications in trace detection and identification. When it is applied into environmental monitoring, we should concern several key points to improve detection sensitivity and selectivity for the detection in complex matrix. In this tutorial review, we mainly focus on the strategies for improving the use of SERS into environmental application. The strategies are summarized for enhancing the ability of the substrate to selectively capture specific targets, and for achieving separation and concentration of the analytes from the matrix and the assembly structures for multiple phase detection. We have also introduced several newly developed detection systems using portable instruments and miniaturized devices that are more suitable for infield applications. In addition, we discuss the present challenges that hide it from wide real application and give the outlook for the future development in applying SERS in environmental monitoring

Novel Approaches to Prepare and Utilize SERS Substrates: Multiplex Microfluidics and Nanotransfer Printing

Over the past few decades, surface enhanced Raman spectroscopy (SERS) has garnered respect as an analytical technique with significant chemical and biological applications. SERS is important for the life sciences because it can provide trace level detection and a high level of molecular structure information. The development of quantitative, highly sensitive substrates requires control over size, shape, and position of metal nanoparticles which function as the SERS active medium. Thus, creating and successfully implementing a sensitive, reproducible, and robust SERS active substrate continues to be a challenging ask. Its future development depends critically on techniques for lithography and nanofabrication. Herein, we report a novel method for SERS that is based upon using colloidal silver nanoparticles in a multiplexed microfluidics (MMFs) platform. The MMF is created in polydimethylsiloxane (PDMS) polymer material and used to perform parallel, high throughput, and sensitive detection/identification of single or various analytes under easily manipulated conditions. A facile passive pumping method is used to deliver samples into the channels under flowing conditions that are highly conducive for SERS measurments. Also an unconventional nanofabrication approach is modified to produce efficient SERS substrates. Metallic nanopatterns of silver discs are transferred from a stamp onto PDMS to create nanocomposite substrates with regular periodic morphologies. The stamp with periodic arrays of square, triangular, and elliptical pillars is created via Electron Beam Lithography of ma-N 2403 resist. A modified cyclodextrin is thermally evaporated on the stamp to overcome the adhesive nature of the ebeam resist and to function as a releasing layer. Subsequently, the stamp is over coated with Ag by physical vapor deposition at a controlled rate and thickness and used directly for nanotransfer printing (nTP). Stamps, substrates, and the efficiency of the nTP process were explored by SEM. Ag nano-disc-PDMS substrates are studied by SERS using Rhodamine 6G as the probe analyte. The SERS response of metallic nano-discs of various shapes/sizes on the original stamp is compared to the corresponding nTP substrates. We demonstrate that physical manipulation of the PDMS post nTP can be used to alter morphology. Additionally, stamps are shown to be reusable after the nTP process