Nanotoxicity assessment: A challenging application for cutting edge electroanalytical tools

Current and Future Technologies for the Detection of Antibiotic-Resistant Bacteria

Antibiotic resistance is a global public health concern, posing a significant threat to the effectiveness of antibiotics in treating bacterial infections. The accurate and timely detection of antibiotic-resistant bacteria is crucial for implementing appropriate treatment strategies and preventing the spread of resistant strains. This manuscript provides an overview of the current and emerging technologies used for the detection of antibiotic-resistant bacteria. We discuss traditional culture-based methods, molecular techniques, and innovative approaches, highlighting their advantages, limitations, and potential future applications. By understanding the strengths and limitations of these technologies, researchers and healthcare professionals can make informed decisions in combating antibiotic resistance and improving patient outcomes.

A Review of Analytical Techniques for the Determination and Separation of Silver Ions and Its Nanoparticles

Many articles have already been published dealing with silver ions and its nanoparticles, but mostly from the environmental and toxicological point of view. This article is a review focused on the various analytical techniques and detection platforms used in the separation and determination of mentioned above species, especially on the trace concentration level. Commonly used are optical methods because of their high sensitivity and easy automation. The separation methods are mainly used for the separation and preconcentration of silver particles. Their combination with other analytical techniques, mainly inductively coupled plasma mass spectrometry (ICP-MS) leads to very low detection limits of analysis. The electrochemical methods are also powerful and perspective mainly because of the fabrication of new sensors designed for silver determination. All methods may be combined with each other to achieve a synergistic improvement of analytical parameters with an impact on sensitivity, selectivity and reliability. The paper comprises a review of all three types of analytical methods on the determination of trace quantities of silver ions and its nanoparticles.

Biofilm control strategies in the light of biofilm-forming microorganisms

Biofilm is a complex consortium of microorganisms attached to biotic or abiotic surfaces and live in self-produced or acquired extracellular polymeric substances (EPSs). EPSs are mainly formed by lipids, polysaccharides, proteins, and extracellular DNAs. The adherence to the surface of microbial communities is seen in food, medical, dental, industrial, and environmental fields. Biofilm development in food processing areas challenges food hygiene, and human health. In addition, bacterial attachment and biofilm formation on medical implants inside human tissue can cause multiple critical chronic infections. More than 30 years of international research on the mechanisms of biofilm formation have been underway to address concerns about bacterial biofilm infections. Antibiofilm strategies contain cold atmospheric plasma, nanotechnological, phage-based, antimicrobial peptides, and quorum sensing inhibition. In the last years, the studies on environmentally-friendly techniques such as essential oils and bacteriophages have been intensified to reduce microbial growth. However, the mechanisms of the biofilm matrix formation are still unclear. This review aims to discuss the latest antibiofilm therapeutic strategies against biofilm-forming bacteria.

Sensitive biosensors based on topological insulator Bi2Se3 and peptide

In this work, we designed a facile and label-free electrochemical biosensor based on intrinsic topological insulator (TI) Bi₂Se₃ and peptide for the detection of immune checkpoint molecules. With topological protection, Bi₂Se₃ could have robust surface states with low electronic noise, which was beneficial for the stable and sensitive electron transport between electrode and electrolyte interface. The peptides are easily synthesized and chemically modified, and have good biocompatibility and bioavailability, which is a suitable candidate as the recognition units for immune checkpoint molecules. Therefore, the peptide/Bi₂Se₃ was developed as a suitable working electrode for the electrochemical biosensor. The basic performance of the designed peptide/Bi₂Se₃ biosensor was investigated to determine the Anti-HA Tag Antibody and PD-L1 molecules. The linear detection range was from 3.6 × 10^-10 mg mL^-1 to 3.6 × 10^-5 mg mL^-1, and the detection limit was 1.07 × 10^-11 mg mL^-1. Moreover, the biosensor also displayed good selectivity and stability.

Where Is Nano Today and Where Is It Headed? A Review of Nanomedicine and the Dilemma of Nanotoxicology

Worldwide nanotechnology development and application have fueled many scientific advances, but technophilic expectations and technophobic demands must be counterbalanced in parallel. Some of the burning issues today are the following: (1) Where is nano today? (2) How good are the communication and investment networks between academia/research and governments? (3) Is there any spotlight application for nanotechnology? Nanomedicine is a particular arm of nanotechnology within the healthcare landscape, focused on diagnosis, treatment, and monitoring of emerging (such as coronavirus disease 2019, COVID-19) and contemporary (including diabetes, cardiovascular diseases, neurodegenerative disorders, and cancer) diseases. However, it may only represent the bright side of the coin. In fact, in the recent past, the concept of nanotoxicology has emerged to address the dark shadows of nanomedicine. The nanomedicine field requires more nanotoxicological studies to identify undesirable effects and guarantee safety. Here, we provide an overall perspective on nanomedicine and nanotoxicology as central pieces of the giant puzzle of nanotechnology. First, the impact of nanotechnology on education and research is highlighted, followed by market trends and scientific output tendencies. In the next section, the nanomedicine and nanotoxicology dilemma is addressed through the interplay of in silico, in vitro, and in vivo models with the support of omics and microfluidic approaches. Lastly, a reflection on the regulatory issues and clinical trials is provided. Finally, some conclusions and future perspectives are proposed for a clearer and safer translation of nanomedicines from the bench to the bedside.

Advances in Antimicrobial Resistance Monitoring Using Sensors and Biosensors: A Review

The indiscriminate use and mismanagement of antibiotics over the last eight decades have led to one of the main challenges humanity will have to face in the next twenty years in terms of public health and economy, i.e., antimicrobial resistance. One of the key approaches to tackling antimicrobial resistance is clinical, livestock, and environmental surveillance applying methods capable of effectively identifying antimicrobial non-susceptibility as well as genes that promote resistance. Current clinical laboratory practices involve conventional culture-based antibiotic susceptibility testing (AST) methods, taking over 24 h to find out which medication should be prescribed to treat the infection. Although there are techniques that provide rapid resistance detection, it is necessary to have new tools that are easy to operate, are robust, sensitive, specific, and inexpensive. Chemical sensors and biosensors are devices that could have the necessary characteristics for the rapid diagnosis of resistant microorganisms and could provide crucial information on the choice of antibiotic (or other antimicrobial medicines) to be administered. This review provides an overview on novel biosensing strategies for the phenotypic and genotypic determination of antimicrobial resistance and a perspective on the use of these tools in modern health-care and environmental surveillance.

The Role of Peptides in the Design of Electrochemical Biosensors for Clinical Diagnostics

Peptides represent a promising class of biorecognition elements that can be coupled to electrochemical transducers. The benefits lie mainly in their stability and selectivity toward a target analyte. Furthermore, they can be synthesized rather easily and modified with specific functional groups, thus making them suitable for the development of novel architectures for biosensing platforms, as well as alternative labelling tools. Peptides have also been proposed as antibiofouling agents. Indeed, biofouling caused by the accumulation of biomolecules on electrode surfaces is one of the major issues and challenges to be addressed in the practical application of electrochemical biosensors. In this review, we summarise trends from the last three years in the design and development of electrochemical biosensors using synthetic peptides. The different roles of peptides in the design of electrochemical biosensors are described. The main procedures of selection and synthesis are discussed. Selected applications in clinical diagnostics are also described.

Detection, size characterization and quantification of silver nanoparticles in consumer products by particle collision coulometry

Silver nanoparticles (AgNPs) are widely used in industrial and consumer products owing to its antimicrobial nature and multiple applications. Consequently, their release into the environment is becoming a big concern because of their negative impacts on living organisms. In this work, AgNPs were detected at a potential of + 0.70 V vs. Ag/AgCl reference electrode, characterized, and quantified in consumer products by particle collision coulometry (PCC). The electrochemical results were compared with those measured with electron microscopy and single-particle inductively coupled plasma mass spectrometry. The theoretical and practical peculiarities of the application of PCC technique in the characterization of AgNPs were studied. Reproducible size distributions of the AgNPs were measured in a range 10-100 nm diameters. A power allometric function model was found between the frequency of the AgNPs collisions onto the electrode surface and the number concentration of nanoparticles up to a silver concentration of 10¹⁰ L^-1 (ca. 25 ng L^-1 for 10 nm AgNPs). A linear relationship between the number of collisions and the number concentration of silver nanoparticles was observed up to 5 × 10⁷ L^-1. The PCC method was applied to the quantification and size determination of the AgNPs in three-silver containing consumer products (a natural antibiotic and two food supplements). The mean of the size distributions (of the order 10-20 nm diameters) agrees with those measured by electron microscopy. The areas of current spikes from the chronoamperogram allow the rapid calculation of size distributions of AgNPs that impact onto the working electrode.

Combining natural antimicrobials and nanotechnology for disinfecting food surfaces and control microbial biofilm formation

The elimination of microbial surface contaminants is one of the most important steps in Good Manufacturing Practices in order to maintain food safety. This is usually achieved by detergents and chemical sanitizers, although an increased demand exists for the use of natural products for disinfection purposes. Several natural substances present antibacterial activity against the main foodborne pathogens, demonstrating great potential for use in the food industry. Some difficulties such as high volatility, residual taste and/or degradation by exposure to harsh processing conditions have been reported. Nanoparticle encapsulation appears as a strategy to protect bioactive compounds, maintaining their antimicrobial activity and providing controlled release as well. This article presents the potential of natural antimicrobials and their combination with nanotechnological strategies as an alternative for food surface disinfection and prevent microbial biofilm formation.

Multisensor Systems and Arrays for Medical Applications Employing Naturally-Occurring Compounds and Materials

The significant improvement of quality of life achieved over the last decades has stimulated the development of new approaches in medicine to take into account the personal needs of each patient. Precision medicine, providing healthcare customization, opens new horizons in the diagnosis, treatment and prevention of numerous diseases. As a consequence, there is a growing demand for novel analytical devices and methods capable of addressing the challenges of precision medicine. For example, various types of sensors or their arrays are highly suitable for simultaneous monitoring of multiple analytes in complex biological media in order to obtain more information about the health status of a patient or to follow the treatment process. Besides, the development of sustainable sensors based on natural chemicals allows reducing their environmental impact. This review is concerned with the application of such analytical platforms in various areas of medicine: analysis of body fluids, wearable sensors, drug manufacturing and screening. The importance and role of naturally-occurring compounds in the development of electrochemical multisensor systems and arrays are discussed.

Label-Free Bioelectrochemical Methods for Evaluation of Anticancer Drug Effects at a Molecular Level

Cancer is a multifactorial family of diseases that is still a leading cause of death worldwide. More than 100 different types of cancer affecting over 60 human organs are known. Chemotherapy plays a central role for treating cancer. The development of new anticancer drugs or new uses for existing drugs is an exciting and increasing research area. This is particularly important since drug resistance and side effects can limit the efficacy of the chemotherapy. Thus, there is a need for multiplexed, cost-effective, rapid, and novel screening methods that can help to elucidate the mechanism of the action of anticancer drugs and the identification of novel drug candidates. This review focuses on different label-free bioelectrochemical approaches, in particular, impedance-based methods, the solid supported membranes technique, and the DNA-based electrochemical sensor, that can be used to evaluate the effects of anticancer drugs on nucleic acids, membrane transporters, and living cells. Some relevant examples of anticancer drug interactions are presented which demonstrate the usefulness of such methods for the characterization of the mechanism of action of anticancer drugs that are targeted against various biomolecules.

Cytotoxicity Study of Ionophore-Based Membranes: Toward On-Body and in Vivo Ion Sensing

We present the most complete study to date comprising in vitro cytotoxicity tests of ion-selective membranes (ISMs) in terms of cell viability, proliferation, and adhesion assays with human dermal fibroblasts. ISMs were prepared with different types of plasticizers and ionophores to be tested in combination with assays that focus on the medium-term and long-term leaching of compounds. Furthermore, the ISMs were prepared in different configurations considering (i) inner-filling solution-type electrodes, (ii) all-solid-state electrodes based on a conventional drop-cast of the membrane, (iii) peeling after the preparation of a wearable sensor, and (iv) detachment from a microneedle-based sensor, thus covering a wide range of membrane shapes. One of the aims of this study, other than the demonstration of the biocompatibility of various ISMs and materials tested herein, is to create an awareness in the scientific community surrounding the need to perform biocompatibility assays during the very first steps of any sensor development with an intended biomedical application. This will foster meeting the requirements for subsequent on-body application of the sensor and avoiding further problems during massive validations toward the final in vivo use and commercialization of such devices.