Kuldeep Mahato

Paper based diagnostics for personalized health care: Emerging technologies and commercial aspects.

Personalized health care (PHC) is being appreciated globally to combat clinical complexities underlying various metabolic or infectious disorders including diabetes, cardiovascular, communicable diseases etc. Effective diagnoses majorly depend on initial identification of the causes which are nowadays being practiced in disease-oriented approach, where personal health profile is often overlooked. The adoption of PHC has shown significantly improved diagnoses in various conditions including emergency, ambulatory, and remote area. PHC includes personalized health monitoring (PHM), which is its integral part and may provide valuable informations on various clinical conditions. In PHC, bio-fluids are analyzed using various diagnostic devices including lab based equipment and biosensors. Among all types of biosensing systems, paper based biosensors are commercially attracted due to its portability, easy availability, cheaper manufacturing cost, and transportability. Not only these, various intrinsic properties of paper has facilitated the development of paper based miniaturized sensors, which has recently gained ASSURED (Affordable, Sensitive, Specific, User-friendly, Rapid and Robust, Equipment free, Deliverable to all end-users) status for point of care diagnosis in miniaturized settings. In this review, importance of paper based biosensors and their compatibility for affordable and low cost diagnostics has been elaborated with various examples. Limitations and strategies to overcome the challenges of paper biosensor have also been discussed. We have provided elaborated tables which describe the types, model specifications, sensing mechanisms, target biomarkers, and analytical performance of the paper biosensors with their respective applications in real sample matrices. Different commercial aspects of paper biosensor have also been explained using SWOT (Strength, Weakness, Opportunities, Threats) analysis.

Shifting paradigm of cancer diagnoses in clinically relevant samples based on miniaturized electrochemical nanobiosensors and microfluidic devices

Cancer is one of leading causes of death in the world and occurs in more than two hundred types according to the National Cancer Institute. Its early diagnosis has been remained a prime focus amongst scientists and clinicians since long, not only to understand the complications but also to mitigate its chance of further proliferation. Nowadays, tremendous advances in nanotechnology-empowered diagnostics are serving a substantial input to identify biomarkers associated with various cancers. These biomarkers are found in different forms including overexpressed proteins/surface antigens, metabolites, miRNA, and the entire cell as well. Several approaches have been adopted to detect such cancer biomarkers, where electrochemical sensors have widely been appreciated due to its high sensitivity, selectivity, robustness, and miniaturized point-of-care cancer diagnostics. Due to its immense importance, the present review has been formulated describing classical concepts of cancer biomarker discovery followed by the recent status of electrochemical biosensors for cancer diagnoses. Particularly, we have summarized the state-of-the-art technologies based on potentiometric, impedimetric, amperometric, voltammetric biosensors for the detection of different biomarkers viz. protein, miRNA, whole cell and biomarkers generated by metabolic shift in response to carcinoma population. Apart from these, we have also highlighted different deliverable microfluidics-based approaches and recent prototypes for cancer detection. To put various perceptive insights on the recent advancements in cancer diagnostics, an extended table is incorporated, which includes sensor fabrication strategies, type of biomarkers, detection strategies, and analytical performance of the cancer biosensor since last five years (2013-2017).

Chitosan stabilized gold nanoparticle mediated self-assembled gliP nanobiosensor for diagnosis of Invasive Aspergillosis

Diagnosis of Invasive Aspergillosis (IA) casused by Aspergillus fumigatus in miniaturized setting is challenging with great importance in human health. In this direction, we have designed a sensitive electrochemical nanobiosensor for diagnosis of IA through detecting the virulent glip target gene (glip-T) in a miniaturized experimetal setting. The sensor probe was fabricated using 1,6-Hexanedithiol and chitosan stabilized gold nanoparticle mediated self-assembly of glip probes (glip-P) on gold electrode. It was characterized by UV-visible spectroscopy, cyclic voltametry and electrochemical impedance spectroscopy. The ability of sensor to detect glip-T was analysed based on the hybridyzation reaction and the signal obtained using toluidine blue as indicator molecule. Analytical parameters were optimized in terms of glip-P concentration, temperature, reaction time, and concentration of toluidine blue. The biosensor showed the dynamic range between 1 × 10-14- 1 × 10-2 M with the detection limit of 0.32 ± 0.01 × 10-14(RSD < 5.2%). The regeneration of biosensor was evaluated and the interference due to non-target oligonucleotide sequences was evaluated individualy as well as in mixed sample to validate the high selectivity of the designed sensor. The stability of the designed sensor was examined and practical applicability of biosensor was tested by detecting glip-T in real sample environment.

Fundamentals and commercial aspects of nanobiosensors in point-of-care clinical diagnostics

Among various problems faced by mankind, health-related concerns are prevailing since long which are commonly found in the form of infectious diseases and different metabolic disorders. The clinical cure and management of such abnormalities are greatly dependent on the availability of their diagnoses. The conventional diagnostics used for such purposes are extremely powerful; however, most of these are limited by time-consuming protocols and require higher volume of test sample, etc. A new evolving technology called “biosensor” in this context shows an enormous potential for an alternative diagnostic device, which constantly compliments the conventional diagnoses. In this review, we have summarized different kinds of biosensors and their fundamental understanding with various state-of-the-art examples. A critical examination of different types of biosensing mechanisms is also reported highlighting the advantages of electrochemical biosensors for its great potentials in next-generation commercially viable modules. In recent years, a number of nanomaterials are extensively used to enhance not only the performance of biosensing mechanism, but also obtain robust, cheap, and fabrication-friendly durable mechanism. Herein, we have summarized the importance of nanomaterials in biosensing mechanism, their syntheses as well as characterization techniques. Subsequently, we have discussed the probe fabrication processes along with various techniques for assessing its analytical performances and potentials for commercial viability.

Smart Materials for Biosensing Applications

The timeline of human civilizations has been demarcated after the name of materials that have been used in abundance in that era such as; iron age, bronze age etc. In addition to the classical materials, there are few other interesting materials which are known for its environmental intelligence and responsiveness, also called as “smart materials”. In modern era smart materials are being employed in various applications including structure building, heat engine manufacturing, microelectromechanical and healthcare systems etc. Recently, the research thrust has been given to the application of such materials into biosensing applications. This article summarizes different types of smart materials that have been being used for biosensing in recent years. Moreover, role of these smart materials for better sensitivity has also been briefly discussed.

Bioinspired Composite Materials: Applications in Diagnostics and Therapeutics

Evolution-optimized specimens from nature with inimitable properties, and unique structure–function relationships have long served as a source of inspiration for researchers all over the world. For instance, the micro/nanostructured patterns of lotus-leaf and gecko feet helps in self-cleaning, and adhesion, respectively. Such unique properties shown by creatures are results of billions of years of adaptive transformation, that have been mimicked by applying both science and engineering concepts to design bioinspired materials. Various bioinspired composite materials have been developed based on biomimetic principles. This review presents the latest developments in bioinspired materials under various categories with emphasis on diagnostic and therapeutic applications.

Electrochemical Immunosensors: Fundamentals and Applications in Clinical Diagnostics

Abstract Immunosensors are the affinity-based biosensing devices that have enormous potential for the next-generation bioanalytical systems. Usually, the components of these self-content devices include biorecognition element, transducers, and the readout systems, where biorecognition systems perceive the physical signals, transducers convert observed input to the quantifiable electrical signals, and the readout systems show the measured signals. For immunosensing, various transducers are used, including electrochemical, optical, and piezoelectric. Usually, these transducers are modified before using in immunosensing platforms, which essentially works on the formation of antigen–antibody complexes. Among all types of the immunosensors, electrochemical immunosensors are widely accepted because of its specificity and high accuracy. Such immunosensors are usually assessed by various bioanalytical techniques for its diagnostic performances. This chapter summarizes the analytical techniques that are generally used to characterize the electrochemical immunosensors and various advanced approaches, i.e., electrochemical lateral flow assays, colorimetric immunosensing, redox cycling, and receptor–ligand–receptor binding bifunctional signal amplification–based approaches have been described with adequate numbers of illustrations. In addition to this, it also highlights various applications of electrochemical immunosensors in clinical diagnostics.