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Selective fluorescence imaging of actin protein hugely depends on the fluorescently labeled actin-binding domain (ABD). Thus, it is always a challenging task to image the actin protein (

The detection of fluoride ions in a competitive environment often poses several challenges. In this work, we have designed and synthesized a coumarin functionalized fluorescein dyad (R3) which represents an ideal through bond energy transfer (TBET) fluorophore with the coumarin unit as donor and fluorescein unit as acceptor. The bichromophoric dyad demonstrates the detection of fluoride ions in the parts per billion (ppb) concentration level (22.8 ppb) with high selectivity via a TBET emission signal at 548 nm with a diagnostic bright yellow colour fluorescence output. Based on UV-visible, fluorescence, 1H NMR and DFT studies, it is shown that the fluoride ion induces the opening of the spirolactam ring of the fluorescein moiety and provides a π-conjugation link between the donor and acceptor units enabling a TBET phenomenon with a larger pseudo-Stokes shift of 172 nm. To the best of our knowledge, this is the first report where the fluoride ion is detected via a TBET signal between the coumarin and fluorescein units in a bichromophoric dyad.

The detection of hydroxylamine in an aqueous medium is challenging due to its very similar chemical reactivity to its nearest competitors such as hydrazine hydrate and primary amines. Moreover, the detection of hydroxylamine at neutral pH adds further complexity to the sensing phenomenon due to its poor reactivity in a neutral aqueous medium. In this work, we have presented a diphenyl imidazole benzaldehyde (DIB) probe which demonstrates the detection of hydroxylamine (HA) in micromolar concentrations with high selectivity in 5% DMSO phosphate buffer solution at pH 7.4 via a fluorescence "turn-on" signal. The interaction of hydroxylamine with the probe has been comprehensively studied by using fluorescence spectroscopy, proton NMR, FTIR, ESI-mass spectrometry and DLS measurements. The experimental results were further corroborated with the DFT studies. These results could pave the way toward the development of molecular indicators for hydroxylamine in chemical and biological platforms.

We explored the antibacterial potential (alone and combination) against multidrug resistant (MDR) Pseudomonas aeruginosa isolates KG-P2 using synthesized thieno[3,2-c]pyran-2-ones in combination with different antibiotics. Out of 14 compounds, two compounds (3g and 3l) abridged the MIC of tetracycline (TET) by 16 folds. Compounds was killing the KG-P2 cells, in time dependent manner, lengthened post-antibiotic effect (PAE) of TET and found decreased the mutant prevention concentration (MPC) of TET. In ethidium bromide efflux experiment, two compounds repressed the drug transporter (efflux pumps) which is further supported by molecular docking of these compounds with efflux complex MexAB-OprM. In another study, these compounds inhibited the synthesis of biofilm.

Tetrazoles are indispensable nitrogen containing heterocyclic scaffolds that offer a broad spectrum of applications in various domains such as medicinal chemistry, high energy material science, biochemistry, pharmacology etc.

Podocin is expressed in the nephrotic tissues and its mutation inside the gene have been associated to familial idiopathic type 2 nephrotic syndrome. Here we have analyzed the most affected mutation position R138Q of human podocin protein which occurs at SPFH_PODOCIN domain of the titled protein. Molecular docking study has been carried out through AutoDock vina to study the molecular interaction between mutant and wild type models of the studied protein with biological active compounds of Boerhaavia diffusa plant extracts. Both boeravinone B and F are having higher binding energy as compared to others in mutant protein. Furthermore, molecular dynamics simulation study was carried out of with a trajectory of 50 ns for both the wild type and mutant model. This study reveals that, flexibility nature decreases in the mutant protein. The recognition of disease related non-synonymous single nucleotide polymorphisms and analysis of their effects by computational approaches has potential to provided knowledge for the diagnosis, and treatment of diseases like nephrotic syndrome.

In the present work, zeolitic imidazole framework-8 (ZIF-8), a special class of metal organic framework (MOF) was prepared under a cleaner and greener synthesis route. ZIF-8 was characterized by using powder X-ray diffraction (PXRD), fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermo gravimetric analysis (TGA) and UV–Visible diffused reflectance spectroscopy (UV-DRS). The material was used to remove reactive blue-4 (RB4) from aqueous media via physical adsorption process. The adsorption kinetics, isotherms, effects of dose and ionic strengths were studied. The results of the above studies concluded that pseudo-second-order kinetics model and Freundlich isotherm fitted well with our experimental adsorption data. Thermodynamics parameters of adsorption like enthalpy, entropy and free energy were evaluated. The sorption process has taken place spontaneously and it was exothermic in nature. The adsorption of RB4 was discussed focusing on electrostatic attractions, pore-filling effects, π–π interactions and hydrogen bonding interactions. The results from this study indicated the ability of ZIF-8 to adsorb dye efficiently and its potential applications in wastewater treatment.

A thiocarbonohydrazone locked salicylidene based macrocycle ligand L has been synthesized and its ion sensing properties were examined by UV–visible and fluorescence spectroscopy. The macrocycle serves as a highly selective colorimetric sensor for Hg2+ ions while it acts as an excellent fluorescent sensor for Zn2+ ions by exhibiting a green fluorescence at 498 nm even in the presence of interfering ions. A detailed analysis of binding characteristics such as complex stoichiometry, association constant and detection limits of L toward Hg2+ and Zn2+ ions were evaluated by UV–visible and fluorescence experiments which revealed a stronger binding affinity and higher detection limit of L toward the mercury ions. Further, the sequential displacement strategy for the chromofluorogenic detection of Zn2+, Hg2+ and S2− ions by ligand L, has been studied comprehensively. Finally, the ion-responsive fluorescence output signal of L were employed to design a molecular keypad lock which could be accessible by two users having two different set of chemical passwords (inputs) through distinguishable optical trajectories.

Detection of ions in chemical, biological and environmental samples has gathered tremendous momentum considering the beneficial as well as adverse effects of the ions. Generally, most of the ions are beneficial up to an optimum concentration, beyond which they are toxic to human health. However, most of the fluorescence-based ion sensors are only active in non-aqueous solution because of the low solubility of the sensor molecules in aqueous buffer medium. In the present work, we have demonstrated that encapsulation of an aqueous insoluble thiocarbonohydrazone-locked salicylidene-based macrocyclic ligand in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membranes allows the selective detection of Zn2+ in aqueous medium with approximately 3-fold enhanced efficiency compared to its efficiency in DMSO medium. We have further modulated the charge of the membrane surface by adding various concentrations of a negatively charged lipid, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG), and showed that negative surface charge further enhances the Zn2+ sensing efficiency up to approximately 6-fold. This strategy opens up a new avenue of utilizing organic sensors to detect vital ions in aqueous medium.

This work reports the aggregation induced emission (AIE) behaviour of a coumarin-salicylidene Schiff base probe 3 which shows bright yellow AIE fluorescence in DMSO–water medium (fw 80%) buffered by 10 mM HEPES at pH 7.4. The aggregated probe (AIEgen-3) selectively discriminates Cu2+ ions over a series of other interfering metal ions via a fluorescence “on–off” strategy through a CHEQ process. DLS measurements revealed an average particle size of 372 nm for AIEgen-3 at an 80% water fraction, which dramatically increases to 656 nm in the presence of Cu2+ ions, indicating the formation of more structured aggregates, which was further supported by TEM and ESI-MS experiments. A comprehensive analysis of the binding characteristics and interference studies of AIEgen-3 with various metal ions have been carried out by fluorescence and UV-visible experiments. AIEgen-3 shows a fluorescence detection limit (LOD) of 24 nM (∼1.5 ppb) for Cu2+ ions, which is considerably far below the values of detection limits recently reported for other Cu2+ ion sensors in aqueous medium. Further, the analytical applications of AIEgen-3 have been demonstrated by the estimation of Cu2+ ions in tap water and pharmaceutical samples both in solution and the solid phase, which shows the potentiality of the probe for on-site detection of Cu2+ ions in chemical, environmental and biological samples.

A protein's function is closely related to its structural properties. Mutations can affect the functionality of a protein. Different cancer tissues have found disordered expression of the cyclin-dependent kinase 2-associated Protein 1 (CDK2AP1) gene. A protein molecule's conformational flexibility affects its interaction with phytochemicals and their biological partners at various levels.

Metal–organic frameworks (MOFs) are organic–inorganic porous hybrid crystalline materials with extremely high surface areas and tunable pore sizes. These materials have attracted researchers across the globe for their structural diversity and tunable properties, as well as their well-designed topology. These classes of materials have numerous applications in a number of fields such as sensing, gas storage, gas separation, adsorption, purification and separation of liquid, imaging, drug delivery, heterogeneous catalysis, and so on. Among these wide range of applications of MOFs, many MOFs exhibit photocatalytic activity and are being used as photocatalysts to eliminate organic pollutions such as organic dyes. MOFs containing metals like Co, Ni, Zr, Ti, Al, Cr, Fe, Ce, Tb, Dy, and Zn are being reported to be very impressive as photocatalysts for organic dye degradation. We strongly believe that this chapter will encourage researchers to develop new heterogeneous catalysts based on MOFs to use solar power to degrade toxic organic dyes to mitigate environmental pollution.

A protein's function is closely related to its structural properties. Mutations can affect the functionality of a protein. Different cancer tissues have found disordered expression of the cyclin-dependent kinase 2-associated Protein 1 (CDK2AP1) gene. A protein molecule's conformational flexibility affects its interaction with phytochemicals and their biological partners at various levels. Boerhavia diffusa has been investigated most extensively for its medicinal activities like anticancer properties. It contains many bioactive compounds like Boeravinone A, Boeravinone B, Boeravinone C, Boeravinone D, Boeravinone E, Boeravinone F, Boeravinone G, Boeravinone H, Boeravinone I and Boeravinone J. We have studied to analyse the binding efficacy properties as well as essential dynamic behaviour, free energy landscape of both the native and mutant protein CDK2AP1 with bioactive compounds from Boerhavia diffusa plant extracts through computational approaches by homology modelling, docking and molecular dynamics simulation. From the molecular docking study, we found that. Boeravinone J have best binding affinity (–7.9 kcal/mol) towards the native protein of CDKAP1 compared to others phytochemicals. However, we found the binding energy for H23R and C105R (mutation point) −7.8 and −7.6 kcal/mol, respectively. A single minima energy point (from 100 ns molecular dynamics simulation study) was found in the H23R mutant with Boeravinone J complex suggested that minimum structural changes with less conformational mobility compared C105A mutant model. Communicated by Ramaswamy H. Sarma

The development of new approaches to improve screening, diagnosis, prevention and treatment of cancer is an area of intensive research. Breast cancer is one such widespread category of cancer among women which is the world’s second leading cause of cancer death universally. The objective of this study is to analyze the structural stability of different diseased mutants of HER2 protein as well as to find out the inhibitory effects of Ru-terpyridine over mutant HER2 protein. To accomplish the study insight, we have carried out using different computational tools. From our in silico study, we conclude that, after mutation at positions D769H and V777L in HER2 protein, it was proceeded to cancerous growth and it becomes destabilize, followed by the binding performance of the ruthenium terpyridine over mutant HER2 protein shows the inhibitory effect against HER2 protein-targeted breast cancer.

Like common cold and flu, SARC-CoV-2 virus spreads by droplets of sneezes or coughs which virus affects people of various age groups. Today, this virus is almost distributed all over the world. Since binding process plays a crucial role between host and receptor, therefore, we studied the molecules intended toward inhibition process through molecular docking and molecular dynamics simulation process. From the molecular docking study, it is noteworthy that remdesivir shows better binding affinity toward the main protease of SARS-CoV2 compared to other studied drugs. Within studied phytochemicals, carnosic acid shows better binding poses toward main protease of SARS-CoV2 among studied phytochemicals. The amino acid residues GLN110 and PHE294 were almost found in all the studied interactions of drugs and phytochemicals with main protease of SARS-CoV-2. Furthermore, the results show a larger contribution of the Van der Waals energies as compared to others like electrostatic energies suggesting that ligands at the binding pocket are predominantly stabilized by hydrophobic interactions. The conformational change during ligand binding was predicted from Gibbs free energy landscape analysis through molecular dynamics simulation. We observed that, there were two main free energy basins for both docked carnosic acid complex and for docked remdesivir complex, only one main free energy basin was found in the global free energy minimum region. Communicated by Ramaswamy H. Sarma

The blue color of butterfly pea (Clitoria ternatea) was extracted by Milli-Q water and evaluated for selective detection of bisulphate (HSO

Analysis of structural and functional binding performance of proteins related to genetic basis of diseases is a measure challenge. Podocin protein is a member of flotillin, stomatin and prohibitin, which expressed in nephron tissue. Type 2 nephrotic syndrome (NPHS2) occurs due to mutation in podocin protein. In the present article we have evaluated the binding performance of podocin protein both native as well as mutant with different phytochemicals like aegeline and berberine. We found that aegeline shown better inhibitory effect as compare to berberine against type 2 nephrotic syndrome.

The recent advancements in biotechnology and biomarkers discovery are now refining many biological systems in disease and diagnostic. The growing demand of application of biosensors in the field of medical diagnostic is because of its high sensitivity and multifunctional performances by a single chip. Currently, biosensor is widely used in health care, particularly diagnosis of infectious diseases as the number of predicted deaths remains high, with the pandemics and epidemics hazards and antibiotics resistance to various pathogens. The current scenario of biosensor technologies has potential to convey bed-side diagnostics, which matches traditional standards with respect to cost, accuracy, and time. Nevertheless, constant refinement in the technology is needed in order to provide lab-on-chip rapid, affordable, and accurate diagnostic. In this chapter, the importance of biosensor to diagnose several infectious as well as pathogenesis diseases like malaria has been discussed. Previous studies have stated that both Plasmodium falciparum dihydrofolate reductase–thymidylate synthase (PfDHFR-TS) and P. falciparum heme detoxification protein (PfHDP) are promising biomarker targets for malaria. Herein, in-depth analysis underpinning molecular interaction of PfDHFR and PfHDP with heme is studied employing molecular docking approach. Various structure validation tools confirmed the reliability of the modeled structures. The binding energy was found to be −7.47 kcal/mol and −9.61 kcal/mol for docked PfHDP and heme and PfDHFR-TS and heme complexes, respectively. The binding energy and other parameters like intermolecular energy and electrostatic energy corroborated that heme could perform better sensing strength toward PfDHFR-TS.

The Internet of Things (IoT) represents a new direction in modeling and monitoring biomedical data. A wide variety of devices embedded with sensors and actuators interconnected over the Internet can now interface directly with one another, allowing for quick and precise collection and analysis of data. This presents all sorts of interesting possibilities for the field of healthcare, one of which is the heart rate monitoring system proposed in this chapter. The system uses a pulse sensor attached to a person’s fingertip to measure heart rate in beats per minute. The data generated is visualized via liquid crystal display and stored in the cloud for later use and analysis. With the help of the IoT, patients can be monitored continuously and real-time data can be collected and shared. This allows for more precise diagnosis and management of cardiovascular conditions. This chapter presents our proposed system and explains how it works.

Continuous investments made by government of India in healthcare information technology as well as various health care programmers allow a revolution in healthcare and technology sector. This revolution helps in improvement of quality and reduction of cost in this field. However in the present scenario the healthcare systems are still in pitiable condition in many rural areas. Most of the time the lack of effective communication between patient and doctor creates ample of health hazards in rural areas. To avoid the communication gap and early prediction of diseases in rural community a pipeline is modeled in the present study, which is based on human whole genome sequencing to protein sequence and the diagnosis of disease by using different biomarkers and computational techniques. Advances in computational methodologies have ushered of innovations in calculation, visualization and prediction of factors relating to different diseases with novel strategies like protein interactive networks comparative genomics, bioinformatics and different online/offline software and tools. By the help of this studied modeled strategy doctor can easily predict the diseases and refer to the patient for early treatment. The health hazards in rural areas can be minimized with constructive application of this method in health care system.

Two chromofluorescent coumarin-functionalized salicylidene based probes (3a and 3b) have been synthesized and evaluated for selective detection of fluoride and cyanide ions. Probes 3a and 3b selectively detect fluoride ions in acetonitrile medium via H-bond interaction and subsequent deprotonation to elicit a distinct visual colour change from colourless to deep red with a significant enhancement in their emission intensity to “turn on” a yellow fluorescence. In addition, probe 3a could optically discriminate the presence of cyanide ions over other anions by a colour change from colourless to deep yellow with an enhancement of green fluorescence in aqueous-acetonitrile medium (1:1 v/v). Job’s plot experiments revealed a 1:2 binding stoichiometry between the probes and fluoride or cyanide ions. A detailed analysis of the binding characteristics of probe 3a with fluoride and cyanide ions have been further carried out by 1H NMR titration studies which indicates a good correlation between colorimetric, UV–vis and 1H NMR observations. These experimental results were further corroborated from the theoretical models using quantum chemical calculations.

A base-mediated carbocyclization study has been performed between two allowed Baldwin cyclization modes (6-exo-trig and 6-exo-dig) and it was found that 6-exo-trig cyclization was preferred over 6-exo-dig. Allyl cyanide was found to be suitable and efficient pronucleophile for this investigation and two sp2–sp2 transition-metal-free C−C bond formations took place in a single operation to yield two differently functionalized biaryl compounds.

It is very much necessary to properly manage and screen the most optimal data, avoiding redundancy in the place of necessity. In this chapter, we are examining gene interaction of Alzheimer’s disease (AD) using a string database. Through molecular docking analysis, we studied binding energy, binding residue, bond name, and bond length of the interaction between the proteins that are most targeted with drugs for AD. In this chapter, we have tried to demonstrate some of the approaches that can be implemented for screening of genes and proteins related to a common human genetic disorder. Using virtual screening, we have collected a list of the most appropriate drugs for the targeted disorder. Finally, we studied the interaction between drugs and each protein, which was carried out using the molecular docking process. We found the TYR 134 is involved in a conventional hydrogen bond in GSK3B and an alstertaullone interaction. Both ILE62 and ASP200 are involved in a π-sigma and π-anion bond, respectively. Between GSK3B and I-5, LYS 85 and ARG141 residue are involved in a hydrogen bond. The residue TYR 134 is involved in a π-π stacking bond.

We have studied different interactions on the basis of the NBO analysis of both conformer of creatinine by using density function theory method. The energy between donor of C1-C3 and acceptor of C2-N8 is 1.69 kcal/mol, donor of C1 - C3 and acceptor of N6 - C11 is 3.96 kcal/mol for amino isomer. However we found the energy difference between C1 - N 6 and C 2 - N9 is 3.90 kcal/mol, C2 - N6 and N7 - H8 is 2.42 kcal/mol and C3 - N7 and C2 - N9 is 3.61 kcal/mol. The occupancy for C1-C3, C1-H4,C1-H5 and C1-N6 are 1.98294,1.97219,1.97491 and1.98091 respectively for amino isomer. For imino isomer we found the occupancy for C1 - C3, C1 - H4, C1 - N6, C3- O11 are 1.97607, 1.97033,1.98459 and 1.99574 respectively. These interaction energies are responsible for stabilization and also some nonbonding interactions enhance the stability.We have studied different interactions on the basis of the NBO analysis of both conformer of creatinine by using density function theory method. The energy between donor of C1-C3 and acceptor of C2-N8 is 1.69 kcal/mol, donor of C1 - C3 and acceptor of N6 - C11 is 3.96 kcal/mol for amino isomer. However we found the energy difference between C1 - N 6 and C 2 - N9 is 3.90 kcal/mol, C2 - N6 and N7 - H8 is 2.42 kcal/mol and C3 - N7 and C2 - N9 is 3.61 kcal/mol. The occupancy for C1-C3, C1-H4,C1-H5 and C1-N6 are 1.98294,1.97219,1.97491 and1.98091 respectively for amino isomer. For imino isomer we found the occupancy for C1 - C3, C1 - H4, C1 - N6, C3- O11 are 1.97607, 1.97033,1.98459 and 1.99574 respectively. These interaction energies are responsible for stabilization and also some nonbonding interactions enhance the stability.

Herein, we present the molecular docking study to find out the comparative study of binding performance between three antifungal proteins like ginkbilobin-2 (PDB ID:3A2E), ripening-associated proteins (PDB ID:1Z3Q) which are plant producing antifungal proteins, where as protein s100-a12 (PDB ID:1E8A) is a human producing antifungal protein with the below discussed compound. The binding energy is found -5.29 kcal/mol, for protein having PDBID: 1E8A. For protein PDB ID:1Z3Q with our studied ligand, the binding energy is found -5.56 kcal/mol and for protein PDBID: 3A2E the binding energy is -5.08 kcal/mol. During our docking study we found three hydrogen bonding pattern are present in the 1E8A, where as four in both the case like 1Z3Q and 3A2E. Besides hydrogen bonds, hydrophobic interactions are present during the interactions.

The synthesis of a covalently bonded new photoresponsive molecular capsule formed from two resorcin [4]arene cavitands by fourfold ether linkages using azobenzene subunits is reported. The new molecular capsule undergoes trans to cis isomerization upon irradiation with 365 nm light and can be reversed back from cis to trans form by means of exposure to visible light (530 nm) in benzene solution. The photo-switchable behaviour was also investigated by H-1 NMR spectroscopy which further substantiated the UV-vis experiment. The quantum chemical calculations both at PM6 as well as at the DFT (B97-D) level of approximation for various stereoisomers starting from all-trans to all-cis indicated an increasing flexibility of these molecular capsules. (C) 2016 Elsevier B.V. All rights reserved.

Both one pot and step wise synthesis of methyl 3,5-diaminothieno[3,2-c]pyridin-4-one-2-carboxylates 6 have been delineated by the reaction of 6-aryl-4-methylthio-2H-pyran-2-one-3-carbonitriles 3, methyl mercaptoacetate and hydrazine hydrate. During the stepwise synthesis, functionalized thieno[3,2-c]pyran-4-ones 4 were isolated and treated with hydrazine hydrate to afford the desired products. Analogously, condensation–cyclisation of 5 with hydrazine hydrate delivered identical products, thieno[3,2-c]pyridin-4-ones 6, in excellent yields. The structure of isolated product 6 was ascertained by spectroscopic and single crystal X-ray diffraction analyses.

Two chromofluorescent thiocarbonohydrazone receptors (4 and 5) functionalized with coumarin derivatives have been synthesized and evaluated for selective detection of fluoride ions. Receptor 4 selectively recognizes fluoride ions via H-bond interaction and subsequent deprotonation to elicit a distinct visual colour change from colourless to pink with a significant 20-fold enhancement in its emission intensity to “turn on” a blue fluorescent. In contrast, receptor 5 exhibited a visible colour change from colourless to deep red upon interaction with fluoride ions over other anions. Detailed analysis of the binding characteristics of these receptors with fluoride ions revealed a 1 : 1 binding stoichiometry at lower concentrations while higher concentrations led to a 1 : 2 binding stoichiometry between the receptor and fluoride ions. These experimental results were further corroborated with quantum chemical calculations.

A Zr (IV) based Metal Organic Framework (MOF), UiO-66 has been synthesized by hydrothermal method, and its application for adsorption of two industrially important anionic dyes, Reactive Blue (RB) and Congo Red (CR) was studied. The MOF was thoroughly characterized by Powder X-ray Diffraction (PXRD),UV-vis Diffused Reflectance Spectra (UV-DRS), Fourier-transform Infrared spectroscopy (FT-IR),Thermo Gravimetric Analysis (TGA), N2 adsorption isotherm, 1H Nuclear Magnetic Resonance spectra (1H NMR), Scanning Electronic Microscopy (SEM) and Transmission Electron Microscopy (TEM). From the obtained results, it has been confirmed that our synthesized MOF is mesoporous in nature. The hierarchical adsorption behavior of the MOF has been studied with the dyes, CR and RB by both experimental and molecular docking methods. The binding energy of UiO-66 was found to be -12.82 kcal/mol with CR and -9.42 kcal/mol with RB. Hydrogen bonding and hydrophobic interaction plays a crucial role during adsorption process of both the dyes. Both ligand efficiency and binding energy of CR is found higher as compared to RB. The comprehensive evidences from our experimental as well as molecular docking studies clearly demonstrated that adsorption of CR is higher as compared to RB by the MOF, UiO-66.

The blue color of butterfly pea (Clitoria ternatea) was extracted by Milli-Q water and evaluated for selective detection of bisulphate (HSO4−) ions. The stability of the Clitoria ternatea extract was established by UV–visible and fluorescence techniques. The blue water extract from Clitoria ternatea selectively recognizes HSO4− ions over various anions via a distinct visual color change from blue to purple with a significant hypsochromic shift of 68 nm in the UV–visible absorption spectra. Thus Clitoria ternatea extract provides a selective real time colorimetric monitoring of HSO4− ions which would pave the way for the development of low cost green analytical tool. This type of detection technique enhances the environmental and economic benefits and can emerge as an alternative form of synthetic chelating sensors.

Solution-processed bulk-heterojunction solar cells (BHJSCs) are the focus of photovoltaic research for the last 20 years due to new materials development, bandgap tunability through molecular design, high efficiency, and cost-effective fabrication and optimization. Much attention has been paid to the design and development of donor materials whereas the development of new electron accepting materials is at its infancy. For a long time fullerene and its derivatives have dominated the field as electron acceptor materials. In last few years, a significant progress has been made towards the development of fullerene-free acceptors (FFA) which in combination with conjugated polymers/oligomers as the donors reached power conversion efficiencies (PCE) up to 14% and exceed those of the fullerene-based OSCs. These sharp growth in PCE makes OSCs as one of the fastest growing solar technology. Specifically, in these devices the choice of FFAs and corresponding complementary donor materials plays critical role in achieving high efficiencies. This chapter summarizes recent development in the design principles of FFAs for BHJSCs. The role of FFAs in binary and ternary devices is discussed as a way to improve the device performance. A special attention is paid to the structure-activity relationships with the device performance and an approach for efficiency enhancement of OSCs.