Highly selective and antifouling electrochemical biosensors for sensitive MicroRNA assaying based on conducting polymer polyaniline functionalized with zwitterionic peptide

Zwitterionic Energetic Materials: Synthesis, Structural Diversity and Energetic Properties

Zwitterionic compounds are an emergent class of energetic materials and have gained synthetic interest of many in the recent years. Due to their better packing efficiencies and strong inter/intramolecular electrostatic interactions, they often ensue superior energetic properties than their salt analogues. A systematic review from the perspective of design, synthesis, and physicochemical properties evaluation of the zwitterionic energetic materials is presented. Depending on the parent ring(s) used for the synthesis and the type of moieties bearing positive and negative charges, different classes of energetic materials, such as primary explosives, secondary explosives, heat resistant explosives, oxidizers, etc., may result. The properties of some of the energetic zwitterionic compounds are also compared with analogous energetic salts. This review will encourage readers to explore the possibility of designing new zwitterionic energetic materials.

Peptide-based self-assembled monolayers (SAMs): what peptides can do for SAMs and vice versa

Self-assembled monolayers (SAMs) represent highly ordered molecular materials with versatile biochemical features and multidisciplinary applications. Research on SAMs has made much progress since the early begginings of Au substrates and alkanethiols, and numerous examples of peptide-displaying SAMs can be found in the literature. Peptides, presenting increasing structural complexity, stimuli-responsiveness, and biological relevance, represent versatile functional components in SAMs-based platforms. This review examines the major findings and progress made on the use of peptide building blocks displayed as part of SAMs with specific functions, such as selective cell adhesion, migration and differentiation, biomolecular binding, advanced biosensing, molecular electronics, antimicrobial, osteointegrative and antifouling surfaces, among others. Peptide selection and design, functionalisation strategies, as well as structural and functional characteristics from selected examples are discussed. Additionally, advanced fabrication methods for dynamic peptide spatiotemporal presentation are presented, as well as a number of characterisation techniques. All together, these features and approaches enable the preparation and use of increasingly complex peptide-based SAMs to mimic and study biological processes, and provide convergent platforms for high throughput screening discovery and validation of promising therapeutics and technologies.

Recent Advances and Biomedical Applications of Peptide-Integrated Conducting Polymers

Conducting polymers (CPs) are of great interests to researchers around the world in biomedical applications owing to their unique electrical and mechanical properties. Besides, they are easy to fabricate and have long-term stability. These features make CPs a powerful building block of modern biomaterials. Peptide functionalization has been a versatile tool for the development of CP-based biomaterials. With the aid of peptide modifications, the biocompatibility, target selectivity, and cellular interactions of CPs can be greatly improved. Reflecting these aspects, an increasing number of studies on peptide-integrated conducting polymers have been reported recently. In this review, various kinds of peptide immobilization strategies on CPs are introduced. Moreover, the aims of peptide modification are discussed in three aspects: enhancing the specific selectivity, avoiding nonspecific adhesion, and mimicking the environment of extracellular matrix. We highlighted recent studies in the applications of peptide-integrated CPs in electrochemical sensors, antifouling surfaces, and conductive biointerfaces. These studies have shown great potentials from the integration of peptide and CPs as a versatile platform for advanced biological and clinical applications in the near future.

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.

The impact of antifouling layers in fabricating bioactive surfaces

Bioactive surfaces modified with functional peptides are critical for both fundamental research and practical application of implant materials and tissue repair. However, when bioactive molecules are tethered on biomaterial surfaces, their functions can be compromised due to unwanted fouling (mainly nonspecific protein adsorption and cell adhesion). In recent years, researchers have continuously studied antifouling strategies to obtain low background noise and effectively present the function of bioactive molecules. In this review, we describe several commonly used antifouling strategies and analyzed their advantages and drawbacks. Among these strategies, antifouling molecules are widely used to construct the antifouling layer of various bioactive surfaces. Subsequently, we summarize various structures of antifouling molecules and their surface grafting methods and characteristics. Application of these functionalized surfaces in microarray, biosensors, and implants are also introduced. Finally, we discuss the primary challenges associated with antifouling layers in fabricating bioactive surfaces and provide prospects for the future development of this field. STATEMENT OF SIGNIFICANCE: The nonspecific protein adsorption and cell adhesion will cause unwanted background "noise" on the surface of biological materials and detecting devices and compromise the performance of functional molecules and, therefore, impair the performance of materials and the sensitivity of devices. In addition, the selection of antifouling surfaces with proper chain length and high grafting density is also of great importance and requires further studies. Otherwise, the surface-tethered bioactive molecules may not function in their optimal status or even fail to display their functions. Based on these two critical issues, we summarize antifouling molecules with different structures, variable grafting methods, and diverse applications in biomaterials and biomedical devices reported in literature. Overall, we expect to shed some light on choosing the appropriate antifouling molecules in fabricating bioactive surfaces.