Optical Biosensors for Diagnostics of Infectious Viral Disease: A Recent Update

An overview of biosensor advancements for detecting botulinum neurotoxins: Addressing food safety and biowarfare risks

Botulinum neurotoxins (BoNTs) are lethal toxins produced by bacteria Clostridium botulinum. Ingestion of BoNTs contaminated foods causes botulism which affects individual's nervous system by blocking the release of neurotransmitters causing flaccid paralysis. This review article deciphers the comprehensive account on mechanism of action of BoNTs, pathogenicity, and various innovative analytical detection techniques of BoNTs in foods. Potential misuse of BoNT as a biowarfare agent is also a major concern. Hence, for the detection of deadly BoNTs various conventional techniques like mouse lethality bioassay (MLB), SNAP-25 assay, mouse phrenic nerve hemidiaphragm (MPN) test, non-lethal mouse flaccid paralysis assay (NFPA) and modern techniques (immunoassays, cell-based assay, nucleic acid-based methods, endopeptidase mass spectrometry assays) have been discussed. This article also provides a detailed account on biosensing technology for detecting BoNTs in foods. Moreover, future research efforts should be focused on the development of advanced new-age biosensors for automated detection and real time monitoring of botulinum neurotoxin toxicity in food. Integration of biosensors with quantum technology and lab-on-chip platforms is required for increasing their versatility and robust detection. The insights presented in the review aim towards providing future research directions and increase the vigilance against potential future threats.

Comprehensive Analysis of Advancement in Optical Biosensing Techniques for Early Detection of Cancerous Cells

This investigation presents an overview of various optical biosensors utilized for the detection of cancer cells. It covers a comprehensive range of technologies, including surface plasmon resonance (SPR) sensors, which exploit changes in refractive index (RI) at the sensor surface to detect biomolecular interactions. Localized surface plasmon resonance (LSPR) sensors offer high sensitivity and versatility in detecting cancer biomarkers. Colorimetric sensors, based on color changes induced via specific biochemical reactions, provide a cost-effective and simple approach to cancer detection. Sensors based on fluorescence work using the light emitted from fluorescent molecules detect cancer-specific targets with specificity and high sensitivity. Photonics and waveguide sensors utilize optical waveguides to detect changes in light propagation, offering real-time and label-free detection of cancer biomarkers. Raman spectroscopy-based sensors utilize surface-enhanced Raman scattering (SERS) to provide molecular fingerprint information for cancer diagnosis. Lastly, fiber optic sensors offer flexibility and miniaturization, making them suitable for in vivo and point-of-care applications in cancer detection. This study provides insights into the principles, applications, and advancements of these optical biosensors in cancer diagnostics, highlighting their potential in improving early detection and patient outcomes.

Unlocking new frontiers in healthcare: The impact of nano-optical biosensors on personalized medical diagnostics

Nano-optical biosensors have emerged as transformative tools in healthcare and clinical research, offering rapid, portable, and specific diagnostic solutions. This review critically analyzes the recent advancements, translational challenges, and sustainable approaches in nano-optical biosensor implementation for biomedical applications. We explore the integration of innovative nanomaterials, microelectronics, and molecular biology techniques that have significantly enhanced biosensor sensitivity and specificity, enabling detection of biomarkers ranging from cancer indicators to cardiovascular markers. The potential of nanoplasmonic and silicon photonic biosensors in overcoming current limitations is discussed, alongside the promising integration of artificial intelligence and Internet of Things technologies for improved data analytics and clinical validation. We address key challenges, including size constraints, energy efficiency, and integration with existing technologies, and propose sustainable strategies for eco-friendly materials, energy-efficient designs, and circular economy approaches. The review also examines emerging trends such as multiplexed sensing platforms, wearable biosensors, and their applications in personalized medicine. By critically assessing these developments, we provide insights into the prospects of nano-optical biosensors and their potential to revolutionize point-of-care diagnostics and personalized healthcare, while emphasizing the need for interdisciplinary collaboration to overcome remaining obstacles in translating these technologies from laboratory research to real-world clinical applications.

Current trends and future potential in the detection of avian coronaviruses: An emphasis on sensors-based technologies

Infectious bronchitis virus (IBV), an avian coronavirus, member of the genus Gammacoronavirus, poses significant threats to poultry health, causing severe respiratory, reproductive, and renal infections. The genetic diversity of IBV, driven by mutations, recombination and deletions, has led to the emergence of numerous serotypes and genotypes, complicating both diagnosis and control measures. Rapid and accurate diagnostic tools are essential for effective disease management and minimizing economic losses. Conventional diagnostic methods, such as PCR, virus isolation, and serological assays, are hindered by limitations in sensitivity, specificity, and turnaround time. In contrast, innovative biosensor platforms employing advanced detection mechanisms-including electrochemical, optical, and piezoelectric sensors-offer a transformative solution. These technologies provide portable, highly sensitive, and rapid diagnostic platforms for IBV detection. Beyond addressing the challenges of conventional methods, these biosensor-based approaches facilitate real-time monitoring and enhance disease surveillance. This review highlights the transformative potential of biosensors and their integration into diagnostic strategies for avian coronavirus infections, presenting them as a promising alternative for precise and efficient IBV detection.

Silicon-Based Biosensors: A Critical Review of Silicon's Role in Enhancing Biosensing Performance

This review into recent advancements in silicon-based technology, with a particular emphasis on the biomedical applications of silicon sensors. Owing to their diminutive size, high sensitivity, and intrinsic compatibility with electronic systems, silicon-based sensors have found widespread utilization across healthcare, industrial, and environmental monitoring domains. In the realm of biomedical sensing, silicon has demonstrated significant potential to enhance human health outcomes while simultaneously driving progress in microfabrication techniques for multifunctional device development. The review systematically examines the versatile roles of silicon in the fabrication of electrodes, sensing channels, and substrates. Silicon electrodes are widely used in electrochemical biosensors for glucose monitoring and neural activity recording, while sensing channels in field-effect transistor biosensors enable the detection of cancer biomarkers and small molecules. Porous silicon substrates are applied in optical biosensors for label-free protein and pathogen detection. Key challenges in this field, including the interaction of silicon with biomolecules, the economic barriers to miniaturization, and issues related to signal stability, are critically analyzed. Proposed strategies to address these challenges and improve sensor functionality and reliability are also discussed. Furthermore, the article explores emerging developments in silicon-based biosensors, particularly their integration into wearable technologies. The pivotal role of artificial intelligence (AI) in enhancing the performance, functionality, and real-time capabilities of these sensors is also highlighted. This review provides a comprehensive overview of the current state, challenges, and future directions in the field of silicon-based biomedical sensing technologies.

The role of DNA nanotechnology in medical sensing

This paper explores how DNA nanotechnology enhances biosensors in medicine and pharmacology by taking advantage of the unique characteristics of DNA and the unique advantages of DNA origami technology. DNA origami allows the establishment of complex nanoobjects with precise size and complete molecular writability as well as the possibility of seamless integration and biocompatibility with biological systems. Utilizing this, the chemical denaturation of DNA chains allows for the combination of various functions, including organic fluorescence groups and photoreaction elements, etc. This has allowed DNA origami to become a transformative tool in biotechnology and other fields because of its versatility, use in innovative applications improving the design and function of biosensors, and potential to provide greater possibilities for early disease diagnosis and personalized medicine.

Biosensor Technology: Advances and Applications in Livestock Infectious Disease Diagnosis

Biosensors have revolutionized the diagnosis of infectious diseases in livestock by offering sensitive and rapid detection methods for important pathogens. These devices, particularly luciferase-based biosensors, convert biological responses into quantifiable signals, enabling the real-time, non-invasive monitoring of critical biomarkers. This review explores the development and advantages of biosensors, focusing on their applications in detecting important livestock pathogens, including bacteria, parasites, and viruses. By comparing biosensors with traditional diagnostic methods, the review highlights their superior sensitivity and specificity in diagnosing obstetric infections. Furthermore, it discusses the broader utility of biosensors in monitoring gene expression, protein localization, and cellular events. Together, biosensors provide new tools for the timely diagnosis of infectious diseases in livestock and are critical to improving livestock health.

Recent Advances in the Role of Different Nanoparticles in the Various Biosensors for the Detection of the Chikungunya Virus

Humans contract the Chikungunya virus (CHIKV), an alphavirus transmitted by mosquitoes that induces acute and chronic musculoskeletal discomfort and fever. Millions of cases of the disease have been attributed to CHIKV in the Indian Ocean region since 2004, and the virus has since spread to Europe, the Middle East, and the Pacific. The exponential proliferation of CHIKV in recent times underscores the critical nature of implementing preventative measures and exploring potential control strategies. The principal laboratory test employed to diagnose infection in serum samples collected over six days after the onset of symptoms is the detection of CHIKV or viral RNA. Although two commercially available real-time reverse transcription-polymerase chain reaction products exist, data on their validity are limited. A diagnostic instrument that is rapid, sensitive, specific, and cost-effective is, therefore an absolute necessity, particularly in developing nations. Biosensors have demonstrated considerable potential in the realm of pathogen detection. The rapid and sensitive detection of viruses has been facilitated by the development of numerous types of biosensors, including affinity-based nano-biosensors, graphene affinity-based biosensors, optical nano-biosensors, surface Plasmon Resonance-based optical nano-biosensors, and electrochemical nano-biosensors. Furthermore, the utilization of nanomaterials for signal extension, including but not limited to gold and silver nanoparticles, quantum dots, and iron oxide NPs, has enhanced the precision and sensitivity of biosensors. The developed innovative diagnostic method is time-efficient, precise, and economical; it can be implemented as a point-of-care device. The technique may be implemented in diagnostic laboratories and hospitals to identify patients infected with CHIKV. Throughout this article, we have examined a multitude of CHIKV nano-biosensors and their respective properties. Following a discussion of representative nanotechnologies for biosensors, numerous NPs-assisted CHIKV nano-biosensors are summarized in this article. As a result, we anticipate that this review will furnish a significant foundation for advancing innovative CHIKV nano-biosensors.

An Analysis of Monitoring Solutions for CAR T Cell Production

The chimeric antigen receptor T cell (CAR T) therapy has shown remarkable results in treating certain cancers. It involves genetically modifying a patient's T cells to recognize and attack cancer cells. Despite its potential, CAR T cell therapy is complex and costly and requires the integration of multiple technologies and specialized equipment. Further research is needed to achieve the maximum potential of CAR T cell therapies and to develop effective and efficient methods for their production. This paper presents an overview of current measurement methods used in the key steps of the production of CAR T cells. The study aims to assess the state of the art in monitoring solutions and identify their potential for online monitoring. The results of this paper contribute to the understanding of measurement methods in CAR T cell manufacturing and identify areas where on-line monitoring can be improved. Thus, this research facilitates progress toward the development of effective monitoring of CAR T cell therapies.

Detection strategies of infectious diseases via peptide-based electrochemical biosensors

Infectious diseases have threatened human life for as long as humankind has existed. One of the most crucial aspects of fighting against these infections is diagnosis to prevent disease spread. However, traditional diagnostic methods prove insufficient and time-consuming in the face of a pandemic. Therefore, studies focusing on detecting viruses causing these diseases have increased, with a particular emphasis on developing rapid, accurate, specific, user-friendly, and portable electrochemical biosensor systems. Peptides are used integral components in biosensor fabrication for several reasons, including various and adaptable synthesis protocols, long-term stability, and specificity. Here, we discuss peptide-based electrochemical biosensor systems that have been developed over the last decade for the detection of infectious diseases. In contrast to other reports on peptide-based biosensors, we have emphasized the following points i) the synthesis methods of peptides for biosensor applications, ii) biosensor fabrication approaches of peptide-based electrochemical biosensor systems, iii) the comparison of electrochemical biosensors with other peptide-based biosensor systems and the advantages and limitations of electrochemical biosensors, iv) the pros and cons of peptides compared to other biorecognition molecules in the detection of infectious diseases, v) different perspectives for future studies with the shortcomings of the systems developed in the past decade.

Mo(IV) Ion-Modulated BSA-Protected Gold Nanocluster Probe for Fluorescence Turn-On Detection of Trimethylamine N-Oxide (TMAO)

Trimethylamine N-oxide (TMAO), a molecule produced by the microbiota, has been associated with human health and illness. Its early discovery in body fluids may affect our understanding of the pathophysiology and treatment of many illnesses. Therefore, our knowledge of the pathophysiology and diagnostics of disorders associated with TMAO might be enhanced by the creation of dependable and fast methods for TMAO detection. Therefore, we developed a fluorescent probe for detecting TMAO utilizing an on-off-on strategy. Bovine serum albumin (BSA)@AuNCs luminescence is effectively quenched by Mo4+ because BSA@AuNCs and Mo4+ have a strong binding relationship. Mo4+ ions can substantially decrease the emission intensity of gold nanoclusters by establishing a BSA@AuNCs-Mo system. Then, the luminescence of BSA@AuNCs was restored due to the interaction between Mo4+ and TMAO. A significant linear relationship was seen between the emission intensity and TMAO concentration within the 0-201 μM range, with a detection limit of 1.532 μM. Additionally, the method can measure TMAO in blood and urine samples.

Trends and challenges in electroanalytical biosensing methodologies for infectious viral diseases

Viral pandemic diseases have disruptive global consequences leading to millions of deaths and a severe impact on the global economy. Inadequate preventative protocols have led to an overwhelming demand for intensive care leading to uncontrollable burdens and even breakdown of healthcare sectors across many countries. The rapid detection of viral disease helps in the understanding of the relevant intricacies, helping to tackle infection with improved guidelines. Portable biosensor devices offer promising solutions by facilitating on-site detection of viral pathogens. This review summarizes the latest innovative strategies reported using electroanalytical methods for the screening of viral antigens. The structural components of viruses and their categories are presented followed by the various recognition elements and transduction techniques involved in biosensors. Core sections focus on biosensors reported for viral genomic detection(DNA and RNA) and antigenic capsid protein. Strategies for addressing the challenges of electroanalytical biosensing of viral components are also presented. The advantages, and disadvantages of biorecognition elements and nanozymes for the detection of viral disease are highlighted. Such technical insights will help researchers working in chemistry, and biochemistry as well as clinicians working in medical diagnostics.

Galvanic Displacement Reaction Enabled Specific and Sensitive Detection of Bacteria with a Digital Photocorrosion GaAs/AlGaAs Biosensor

The conjugation of ionic gold with bacterial antibodies makes it possible to induce a specific interaction between targeted bacteria and the surface of a GaAs/AlGaAs biochip. The process of immobilization is based on a galvanic displacement reaction (GDR) involving electron transfer between GaAs and Au3+ ions that leads to the formation of a Au-Ga alloy anchoring bacteria to the biochip surface. The GDR-based immobilization of Escherichia coli on biochips comprising a stack of GaAs/AlGaAs nanolayers (dGaAs = 12 nm, dAlGaAs = 10 nm) was confirmed by X-ray photoelectron spectroscopy and atomic force microscopy-based infrared experiments. We report the successful application of this approach for highly sensitive detection of E. coli with a digital photocorrosion (DIP) biosensor. The photoluminescence (PL) monitored DIP of GaAs/AlGaAs nanolayers results in the formation of a PL intensity maximum whose temporal appearance depends on the electric charge transfer between bacteria and the biochip. The formation of a robust bacteria-biochip interface achieved with the GDR process allowed us to observe the role of bacteria on the temporal position of a PL intensity maximum related to the etching of two pairs of GaAs/AlGaAs nanolayers extending up to 24 nm below the biochip surface. We demonstrate the attractive detection of E. coli at 250 CFU/mL, and we discuss the potential of this approach for designing a family of biosensors addressing the quasi-continuous monitoring of a water environment for the presence of pathogenic bacteria.

Recent Advances in DNA Nanotechnology-Enabled Biosensors for Virus Detection

Virus-related infectious diseases are serious threats to humans, which makes virus detection of great importance. Traditional virus-detection methods usually suffer from low sensitivity and specificity, are time-consuming, have a high cost, etc. Recently, DNA biosensors based on DNA nanotechnology have shown great potential in virus detection. DNA nanotechnology, specifically DNA tiles and DNA aptamers, has achieved atomic precision in nanostructure construction. Exploiting the programmable nature of DNA nanostructures, researchers have developed DNA nanobiosensors that outperform traditional virus-detection methods. This paper reviews the history of DNA tiles and DNA aptamers, and it briefly describes the Baltimore classification of virology. Moreover, the advance of virus detection by using DNA nanobiosensors is discussed in detail and compared with traditional virus-detection methods. Finally, challenges faced by DNA nanobiosensors in virus detection are summarized, and a perspective on the future development of DNA nanobiosensors in virus detection is also provided.

Solid-Phase Optical Sensing Techniques for Sensitive Virus Detection

Viral infections can pose a major threat to public health by causing serious illness, leading to pandemics, and burdening healthcare systems. The global spread of such infections causes disruptions to every aspect of life including business, education, and social life. Fast and accurate diagnosis of viral infections has significant implications for saving lives, preventing the spread of the diseases, and minimizing social and economic damages. Polymerase chain reaction (PCR)-based techniques are commonly used to detect viruses in the clinic. However, PCR has several drawbacks, as highlighted during the recent COVID-19 pandemic, such as long processing times and the requirement for sophisticated laboratory instruments. Therefore, there is an urgent need for fast and accurate techniques for virus detection. For this purpose, a variety of biosensor systems are being developed to provide rapid, sensitive, and high-throughput viral diagnostic platforms, enabling quick diagnosis and efficient control of the virus's spread. Optical devices, in particular, are of great interest due to their advantages such as high sensitivity and direct readout. The current review discusses solid-phase optical sensing techniques for virus detection, including fluorescence-based sensors, surface plasmon resonance (SPR), surface-enhanced Raman scattering (SERS), optical resonators, and interferometry-based platforms. Then, we focus on an interferometric biosensor developed by our group, the single-particle interferometric reflectance imaging sensor (SP-IRIS), which has the capability to visualize single nanoparticles, to demonstrate its application for digital virus detection.

3D plasmonic coral nanoarchitecture paper for label-free human urine sensing and deep learning-assisted cancer screening

Practical human biofluid sensing requires a sensor device to differentiate patients from the normal group with high sensitivity and specificity. Label-free molecular identification from human biofluids allows direct classification of abnormal samples, providing insights for disease diagnosis and finding of new biomarkers. Here, we introduce a label-free surface-enhanced Raman scattering sensor based on a three-dimensional plasmonic coral nanoarchitecture (3D-PCN), which has strong electromagnetic field enhancement through multiple hot spots. The 3D-PCN was synthesized on a paper substrate via direct one-step gold reduction, forming a coral-like nanoarchitecture with high absorption property for biofluids. This was fabricated as a urine test strip and then integrated with a handheld Raman system to develop an on-site urine diagnostic platform. The developed platform successfully classified the human prostate and pancreatic cancer urines in a label-free method supported by two types of deep learning networks, with high clinical sensitivity and specificity. Our technology has the potential to be utilized not only for urinary cancer diagnosis but also for various human biofluid sensing systems as a future point-of-care testing platform.

Recent Progress on Optical Biosensors Developed for Nucleic Acid Detection Related to Infectious Viral Diseases

Optical biosensors have many advantages over traditional analytical methods. They enable the identification of several biological and chemical compounds directly, instantly, and without the need of labels. Their benefits include excellent specificity, sensitivity, compact size, and low cost. In this review, the main focus is placed on the nucleic acid-based optical biosensor technologies, including colorimetric, fluorescence, surface plasmon resonance (SPR), Evanescent-Wave Optical, Fiber optic and bioluminescent optical fibre. The fundamentals of each type of biosensor are briefly explained, and particular emphasis has been placed on the achievements which have been gained in the last decade on the field of diagnosis of infectious viral diseases. Concluding remarks concerning the perspectives of further developments are discussed.

A high-throughput single-particle imaging platform for antibody characterization and a novel competition assay for therapeutic antibodies

Monoclonal antibodies (mAbs) play an important role in diagnostics and therapy of infectious diseases. Here we utilize a single-particle interferometric reflectance imaging sensor (SP-IRIS) for screening 30 mAbs against Ebola, Sudan, and Lassa viruses (EBOV, SUDV, and LASV) to find out the ideal capture antibodies for whole virus detection using recombinant vesicular stomatitis virus (rVSV) models expressing surface glycoproteins (GPs) of EBOV, SUDV, and LASV. We also make use of the binding properties on SP-IRIS to develop a model for mapping the antibody epitopes on the GP structure. mAbs that bind to mucin-like domain or glycan cap of the EBOV surface GP show the highest signal on SP-IRIS, followed by mAbs that target the GP1-GP2 interface at the base domain. These antibodies were shown to be highly efficacious against EBOV infection in non-human primates in previous studies. For LASV detection, 8.9F antibody showed the best performance on SP-IRIS. This antibody binds to a unique region on the surface GP compared to other 15 mAbs tested. In addition, we demonstrate a novel antibody competition assay using SP-IRIS and rVSV-EBOV models to reveal the competition between mAbs in three successful therapeutic mAb cocktails against EBOV infection. We provide an explanation as to why ZMapp cocktail has higher efficacy compared to the other two cocktails by showing that three mAbs in this cocktail (13C6, 2G4, 4G7) do not compete with each other for binding to EBOV GP. In fact, the binding of 13C6 enhances the binding of 2G4 and 4G7 antibodies. Our results establish SP-IRIS as a versatile tool that can provide high-throughput screening of mAbs, multiplexed and sensitive detection of viruses, and evaluation of therapeutic antibody cocktails.

Emerging nanophotonic biosensor technologies for virus detection

Highly infectious viral diseases are a serious threat to mankind as they can spread rapidly among the community, possibly even leading to the loss of many lives. Early diagnosis of a viral disease not only increases the chance of quick recovery, but also helps prevent the spread of infections. There is thus an urgent need for accurate, ultrasensitive, rapid, and affordable diagnostic techniques to test large volumes of the population to track and thereby control the spread of viral diseases, as evidenced during the COVID-19 and other viral pandemics. This review paper critically and comprehensively reviews various emerging nanophotonic biosensor mechanisms and biosensor technologies for virus detection, with a particular focus on detection of the SARS-CoV-2 (COVID-19) virus. The photonic biosensing mechanisms and technologies that we have focused on include: (a) plasmonic field enhancement via localized surface plasmon resonances, (b) surface enhanced Raman scattering, (c) nano-Fourier transform infrared (nano-FTIR) near-field spectroscopy, (d) fiber Bragg gratings, and (e) microresonators (whispering gallery modes), with a particular emphasis on the emerging impact of nanomaterials and two-dimensional materials in these photonic sensing technologies. This review also discusses several quantitative issues related to optical sensing with these biosensing and transduction techniques, notably quantitative factors that affect the limit of detection (LoD), sensitivity, specificity, and response times of the above optical biosensing diagnostic technologies for virus detection. We also review and analyze future prospects of cost-effective, lab-on-a-chip virus sensing solutions that promise ultrahigh sensitivities, rapid detection speeds, and mass manufacturability.

Application of Nanotechnology in COVID-19 Infection: Findings and Limitations

There is an urgent need to address the global mortality of the COVID-19 pandemic, as it reached 6.3 million as of July 2022. As such, the experts recommended the mass diagnosis of SARS-CoV-2 infection at an early stage using nanotechnology-based sensitive diagnostic approaches. The development of nanobiosensors for Point-of-Care (POC) sampling of COVID-19 could ensure mass detection without the need for sophisticated laboratories or expert personnel. The use of Artificial Intelligence (AI) techniques for POC detection was also proposed. In addition, the utilization of various antiviral nanomaterials such as Silver Nanoparticles (AgNPs) for the development of masks for personal protection mitigates viral transmission. Nowadays, nano-assisted vaccines have been approved for emergency use, but their safety and effectiveness in the mutant strain of the SARS-CoV-2 virus remain challenging. Methodology: Updated literature was sourced from various research indexing databases such as PubMed, SCOPUS, Science Direct, Research Gate and Google Scholars. Result: We presented the concept of novel nanotechnology researched discovery, including nano-devices, electrochemical biosensing, nano-assisted vaccine, and nanomedicines, for use in recent times, which could be a formidable step for future management of COVID-19.

Device Processing Challenges for Miniaturized Sensing Systems Targeting Biological Fluids

This article presents a review of device processing technologies used in the fabrication of biomedical systems, and highlights the requirements of advanced manufacturing technology. We focus on biomedical systems that perform diagnostics of fluidic specimens, with analytes that are in the liquid phase. In the introduction, we define biomedical systems as well as their versatile applications and the essential current trends. The paper gives an overview of the most important biomolecules that typically must be detected or analyzed in several applications. The paper is structured as follows. First, the conventional architecture and construction of a biosensing system is introduced. We provide an overview of the most common biosensing methods that are currently used for the detection of biomolecules and its analysis. We present an overview of reported biochips, and explain the technology of biofunctionalization and detection principles, including their corresponding advantages and disadvantages. Next, we introduce microfluidics as a method for delivery of the specimen to the biochip sensing area. A special focus lies on material requirements and on manufacturing technology for fabricating microfluidic systems, both for niche and mass-scale production segments. We formulate requirements and constraints for integrating the biochips and microfluidic systems. The possible impacts of the conventional microassembly techniques and processing methods on the entire biomedical system and its specific parts are also described. On that basis, we explain the need for alternative microassembly technologies to enable the integration of biochips and microfluidic systems into fully functional systems.

Development of Methods for Specific Capture of Biological Targets on Aluminum Substrates: Application to Bacillus subtilis Spore Detection as a Model for Anthrax

Many (if not most) biosensors rely on functional silane coatings as a first step toward covalent immobilization of specific capture molecules. While methods for silanization of silica (SiO2) surfaces are very well developed, less has been done to develop and characterize silanization methods for alternative substrates, such as alumina (Al2O3). In particular, the behavior of Al2O3 coatings grown on aluminum under ambient conditions has not been studied. To address this issue, we have tested solution-phase deposition of two silanes on Al2O3 (3-aminopropyl triethoxysilane and 3-triethoxysilyl)propylsuccinic anhydride) and their applicability to analyte-specific biosensing. Contact angle measurements and imaging via Scanning Electron Microsopy (SEM) were employed to characterize surfaces. We find that 3-aminopropyl triethoxysilane produces well-behaved films and demonstrate that this surface can undergo further reaction with glutaraldehyde followed by an anti-Bacillus subtilis antibody to yield functionalized Al2O3 surfaces capable of specific capture of B. subtilis spores (a model of B. anthracis, the causative organism of Anthrax). In contrast, 3-triethoxysilyl)propylsuccinic anhydride did not behave well with Al/Al2O3 under the reaction conditions tested. In addition to providing specific protocols for Al/Al2O3 functionalization, this work highlights the importance of surface chemistry assessment in the development of new sensors.

Electrochemical Biosensor Based on Laser-Induced Graphene for COVID-19 Diagnosing: Rapid and Low-Cost Detection of SARS-CoV-2 Biomarker Antibodies

The severe acute respiratory syndrome originated by the new coronavirus (SARS-CoV-2) that emerged in late 2019, known to be a highly transmissible and pathogenic disease, has caused the COVID-19 global pandemic outbreak. Thus, diagnostic devices that help epidemiological public safety measures to reduce undetected cases and isolation of infected patients, in addition to significantly help to control the population’s immune response to vaccine, are required. To address the negative issues of clinical research, we developed a Diagnostic on a Chip platform based on a disposable electrochemical biosensor containing laser-induced graphene and a protein (SARS-CoV-2 specific antigen) for the detection of SARS-CoV-2 antibodies. The biosensors were produced via direct laser writing using a CO2 infrared laser cutting machine on commercial polyimide sheets. The presence of specific antibodies reacting with the protein and the K3[Fe(CN)6] redox indicator produced characteristic and concentration-dependent electrochemical signals, with mean current values of 9.6757 and 8.1812 µA for reactive and non-reactive samples, respectively, proving the effectiveness of testing in clinical samples of serum from patients. Thus, the platform is being expanded to be measured in a portable microcontrolled potentiostat to be applied as a fast and reliable monitoring and mapping tool, aiming to assess the vaccinal immune response of the population.