Ashanul Haque

Next generation NIR fluorophores for tumor imaging and fluorescence-guided surgery: A review

Cancer is a group of diseases responsible for the major causes of mortality and morbidity among people of all ages. Even though medical sciences have made enormous growth, complete treatment of this deadly disease is still a challenging task. Last few decades witnessed an impressive growth in the design and development of near infrared (NIR) fluorophores with and without recognition moieties for molecular recognitions, imaging and image guided surgeries. The present article reviews recently reported NIR emitting organic/inorganic fluorophores that targets and accumulates in organelle/organs specifically for molecular imaging of cancerous cells. Near infrared (NIR probe) with or without a tumor-targeting warhead have been considered and discussed for their applications in the field of cancer imaging. In addition, challenges persist in this area are also delineated in this review.

Experimental and Theoretical Investigation for the Level of Conjugation in Carbazole-Based Precursors and Their Mono-, Di-, and Polynuclear Pt(II) Complexes

A series of trimethylsilyl-protected monoalkynes (Me3SiC≡C-R) and bis-alkynes (Me3 SiC≡C-R-C≡CSiMe3) incorporating carbazole spacer groups (R = carbazole-2-yl, carbazole-3-yl, carbazole-2,7-diyl, N-(2-ethylhexyl)carbazole-2,7-diyl, carbazole-3,6-diyl, N-(2-ethylhexyl)carbazole-3,6-diyl), together with the corresponding terminal monoalkynes (H-C≡C-R) and bis-alkynes (H-C≡C-R-C≡C-H), have been synthesized and characterized. The CuI-catalyzed dehydrohalogenation reaction between trans-[(Ph)(Et3P)2PtCl], trans-[(Et3P)2PtCl2], and trans-[(P(n)Bu3)2PtCl2] and the terminal alkynes in (i)Pr2NH/CH2Cl2 affords a series of Pt(II) mono- and diynes, while the dehydrohalogenation polycondensation reactions with trans-[(P(n)Bu3)2PtCl2] under similar reaction conditions yields four Pt(II) poly-ynes of the form trans-[(P(n)Bu3)2Pt-C≡C-R-C≡C-]n. The acetylide-functionalized carbazole ligands and the mono-, di-, and polynuclear Pt(II) σ-acetylide complexes have been characterized spectroscopically, with a subset analyzed using single-crystal X-ray diffraction. The Pt(II) mono-, di-, and poly-ynes incorporating the carbazole spacers are soluble in common organic solvents, and solution absorption spectra show a consistent red-shift between the 2- and 2,7- as well as 3- and 3,6-carbazole complexes. Computational modeling is used to explain the observed spectral shifts, which are related to the enhanced electronic delocalization in the latter systems. These results also indicate that the inclusion of carbazole-2,7-diyl units into rigid-rod organometallic polymers should enhance electronic transport along the chains.

Next Generation Antineoplastic Agents: A Review on Structurally Modified Vinblastine (VBL) Analogues

BACKGROUND Throughout the history of human civilizations, cancer has been a major health problem. Despite the advancements made by modern medical sciences, complete treatment or removal of cancerous cells is still a challenging task. Vinblastine, an alkaloid obtained from Catharanthus roseus (L.) G. Don is one of the prominent antineoplastic agents that is being clinically used. To improve the biological potential and reduce sideeffects of this structurally complex molecule, several related analogues have been reported. The present article reviews recently reported structurally modified vinblastine analogues and its impact on biological activity. METHODS We carried out a comprehensive database search on recently reported vinblastine analogues. Both upper (catharanthine) and lower (vindoline) structural units have been considered. The role of functional group modification on anticancer activities has been discussed. In addition, formulations based on vinblastine being considered by NIH, USA for different types of cancers have also been discussed. RESULTS Around fifty papers were included in the review, including computational and experimental ones. These papers were analysed to discuss the mechanism of action of the parent vinblastine molecule and their analogues. The importance of each functionalities on its anticancer activity have been discussed. This reviewed identified the potential sites of vinblastine core where modification led to improved anticancer activity. Furthermore, several new formulations have also been discussed which are under different phases of clinical trial. CONCLUSION The present article highlights the importance of vinblastine in cancer chemotherapy. Literature survey confirms that it is now possible to synthesize new molecules with activity in picomolar range. Not only the periphery of the molecule, the core structure of this magical molecule can be modified to achieve next generation antineoplastic agents.

Fabrication of composites reinforced with lignocellulosic materials from agricultural biomass

Biomass is the abundant resources for the production of materials and commodity chemicals. However, sustainability of such bioresources for long-term utilization is restricted if only food-crop-based biomass and woody biomass are focused on. Thus, the nonfood waste biomass, such as agricultural residue, can be considered as potential raw materials for the production of different lignocellulosic functional composites. Thus, agricultural residue-based composites are an excellent candidate for the safe and green future. The agricultural component, that is, lignocellulosic materials, can be utilized in the best manner by preparing their composite. Basically, agricultural residues are being produced in very large amount (billions of tons) each year around the world. However, an only minor portion of these generated waste materials is used in the form of fodder, household fuel, etc. The rest of the residue is either discarded or burned, which eventually causes air pollution. Therefore, this chapter deals with the importance of utilizing agricultural residue and method of preparation.

Crystal structure of (E)-2-{[(4-anilinophen­yl)imino]meth­yl}-4-nitro­phenol

The title compound, C19H15N3O3, features an intramolecular O—H⋯N hydrogen bond and an E conformation for the Schiff base unit.

Exosomes: A Paradigm in Drug Development against Cancer and Infectious Diseases

Extracellular vesicles are small single lipid membrane entity secreted by eukaryotic and prokaryotic cells and play an important role in intercellular signaling and nutrient transport. The last few decades have witnessed a plethora of research on these vesicles owing to their ability to answer many hidden facts at the supramolecular level. These extracellular vesicles have attracted the researchers because they act as shuttle agents to transfer biomolecules/drugs between cells. Recently, studies have shown the application of exosomes in tumor therapy and infectious disease control. The present review article shows the importance of exosomes in cancer biology and infectious disease diagnoses and therapy and provides comprehensive account of exosomes biogenesis, extraction, molecular profiling, and application in drug delivery.

Rise of Conjugated Poly-ynes and Poly(Metalla-ynes): From Design Through Synthesis to Structure–Property Relationships and Applications

Conjugated poly-ynes and poly(metalla-ynes) constitute an important class of new materials with potential application in various domains of science. The key factors responsible for the diverse usage of these materials is their intriguing and tunable chemical and photophysical properties. This review highlights fascinating advances made in the field of conjugated organic poly-ynes and poly(metalla-ynes) incorporating group 4-11 metals. This includes several important aspects of conjugated poly-ynes viz. synthetic protocols, bonding, electronic structure, nature of luminescence, structure-property relationships, diverse applications, and concluding remarks. Furthermore, we delineated the future directions and challenges in this particular area of research.

Biomass-based composites from different sources: Properties, characterization, and transforming biomass with ionic liquids

The use of biomass as an energy source has considerably even increased in the current scenario. However, biomass availability is crucial for the implementation of any strategy that focuses on bioresources for fuel, chemicals, and biomaterials. Mostly, lignocellulosic biomass such as wasted bioresources has been employed extensively toward its valorization. Besides consideration of wasted bioresources, it would be essential to intensify the overall agricultural productivity and, at the same time, identify the potential of relatively unexplored bioresources. Due to the diverse natures of biomass materials, their properties widely range and exhibit different behaviors. This chapter shows the properties of biomass in its wide diversity, that is, both physical, chemical, mechanical properties and its characterization. However, the scope of this area is broad; attempts have been made to delineate the property and characterization of biomass and their composites from different bioresources. A brief overview has been shown focusing on current challenges in the development of biomass-based composite from the problem of judicious selection of sustainable biomass to availability and biodegradability and issues. Lastly, an attempt has been made to show an overview of using a green solvent such as ionic liquid in the processing of biomass to different product portfolios.

Biomass nanofibrillar cellulose in nanocomposites

Abstract Macro- and nanocellulose fibers have attracted research attention due to their remarkable properties like biodegradability, high strength, and stiffness, as well as their synthesis and application for development of composites. Macro- and nanocellulose fibers can be employed as a reinforcement agent in composite materials due to their outstanding biodegradation, thermal, and mechanical properties. Due to the hydrophilic nature of cellulose fibers, it is essential to enhance their surface irregularity for the production of composites with improved properties. In this chapter, we have discussed the surface alteration of cellulose nanofibers by various processes. Different synthesis techniques, followed by ionic liquids, properties, categories, and different applications of nanocellulose and their composites, have been examined in this chapter.

Crystal structure of (E)-2,6-di-tert-butyl-4-{[2-(2,4-di­nitro­phen­yl)hydrazinylidene]meth­yl}phenol

The title compound was obtained from the condensation reaction of 3,5-di-tert-butyl-4-hydroxybenzaldehyde and 2,4-dinitrophenylhydrazine. The essential part (including all the non-hydrogen atoms except two methyl carbons) of the molecule lies on a mirror plane, which bisects the t-butyl groups.