Enzymatic Reaction-Coupled, Cooperative Supramolecular Polymerization.

Nature employs sophisticated mechanisms to precisely regulate self-assembly and functions within biological systems, exemplified by the formation of cytoskeletal filaments. Various enzymatic reactions and auxiliary proteins couple with the self-assembly process, meticulously regulating the length and functions of resulting macromolecular structures. In this context, we present a bioinspired, reaction-coupled approach for the controlled supramolecular polymerization in synthetic systems. To achieve this, we employ an enzymatic reaction that interfaces with the adenosine triphosphate (ATP)-templated supramolecular polymerization of naphthalene diimide monomers (NSG). Notably, the enzymatic production of ATP (template) plays a pivotal role in facilitating reaction-controlled, cooperative growth of the NSG monomers. This growth process, in turn, provides positive feedback to the enzymatic production of ATP, creating an ideal reaction-coupled assembly process. The success of this approach is further evident in the living-growth characteristic observed during seeding experiments, marking this method as the pioneering instance where reaction-coupled self-assembly precisely controls the growth kinetics and structural aspects of supramolecular polymers in a predictive manner, akin to biological systems.

Chiroptical Amplification of Induced Circularly Polarized Luminescence in Nucleotide-Templated Supramolecular Polymer.

Efficient circularly polarized luminescence (CPL) from purely organic molecules holds great promise for applications in displays, sensing, and bioimaging. However, achieving high dissymmetry values (glum ) from organic chromophores remains a significant challenge. Herein, we present a bioinspired approach using adenosine triphosphate (ATP)-triggered supramolecular polymerization of a naphthalene diimide-derived monomer (ANSG) to induce CPL with a remarkable glum value of 1.1×10-2 . The ANSG molecules undergo a templated, chiral self-assembly through a cooperative growth mechanism in the presence of ATP, resulting in scrolled nanotubes with aggregation-induced enhanced emission (AIEE) and induced CPL. Furthermore, we demonstrate the concept of chiroptical amplification of induced CPL by efficiently amplifying asymmetry using a mixture of chiral ATP and achiral pyrophosphate. This innovative approach opens numerous opportunities in the emerging field of circularly polarized luminescence.

Tricomponent Supramolecular Multiblock Copolymers with Tunable Composition via Sequential Seeded Growth.

Synthesis of supramolecular block co-polymers (BCP) with small monomers and predictive sequence requires elegant molecular design and synthetic strategies. Herein we report the unparalleled synthesis of tri-component supramolecular BCPs with tunable microstructure by a kinetically controlled sequential seeded supramolecular polymerization of fluorescent π-conjugated monomers. Core-substituted naphthalene diimide (cNDI) derivatives with different core substitutions and appended with ß-sheet forming peptide side chains provide perfect monomer design with spectral complementarity, pathway complexity and minimal structural mismatch to synthesize and characterize the multi-component BCPs. The distinct fluorescent nature of various cNDI monomers aids the spectroscopic probing of the seeded growth process and the microscopic visualization of resultant supramolecular BCPs using Structured Illumination Microscopy (SIM). Kinetically controlled sequential seeded supramolecular polymerization presented here is reminiscent of the multi-step synthesis of covalent BCPs via living chain polymerization. These findings provide a promising platform for constructing unique functional organic heterostructures for various optoelectronic and catalytic applications.

Kinetically controlled synthesis of supramolecular block copolymers with narrow dispersity and tunable block lengths.

Synthesis of supramolecular block copolymers (BCPs) from small monomers has been recently attempted. However, the lack of dispersity and length control of the blocky segments limits its functional outcome. Herein we demonstrate the synthesis of well-defined supramolecular BCPs with tunable block lengths by varying the monomer to seed ratio in a kinetically controlled seeded supramolecular polymerization process. Structured Illumination microscopy (SIM) and spectroscopic analyses provide structural characterization of these supramolecular BCPs, which offers various possibilities as axial organic heterostructures.

Wildlife forensics: A boon for species identification and conservation implications.

Wildlife trade and fraudulence in food, artefacts and cosmetic industries had raised serious concern in protection of the wild faunal diversity. Lack of proper tools and molecular based techniques for identification of wild species are some of the major constrains faced by the judiciary and law enforcement agencies while framing charges against poachers and illicit agitator. The emergence of wildlife forensics serves as a boon in solving long pending cases of wildlife crimes. Wildlife forensics have proven to be fast, accurate and reliable criminal investigation processes with comprehensive coverage and easy accessibility. It has also helped resolving taxonomic disputes, determining spatiotemporal genetic divergence, evolutionary history, origins and even endemism. Collaboration among inter-disciplinary fields has even led to engineered signature markers and phylogenetics for several species. Development in fields of genetics, molecular and evolutionary biology and other omics techniques have further contributed in accurate identification of species. Wildlife forensics, with the support of proper international mega database units for population reference, will be fundamental in wildlife investigations through its unlimited information sharing ability. The efficient conservation of species will, however, require a collaborative approach consisting of national policy makers, local stakeholders and implementation agencies in addition to experts from the scientific communities.

A study on refractive errors among school children in Kolkata.

Childhood visual impairment due to refractive errors is a significant problem in school children and has a considerable impact on public health. To assess the magnitude of the problem the present study was undertaken among the school children aged 5 to 10 years in Kolkata. Detailed ophthalmological examination was carried out in the schools as well as in the Regional Institute of Ophthalmology, Kolkata. Among 2317 students examined, 582 (25.11%) were suffering from refractive errors, myopia being the commonest (n = 325; 14.02%). Astigmatism affected 91 children (3.93%). There is an increase of prevalence of refractive errors with increase of age, but it is not statistically significant (p > 0.05). There is also no significant difference of refractive errors between boys and girls.

Ocular rhinosporidiosis.

Rhinosporidium seeberi, the causative organism causing rhinosporidiosis, also affects extranasal sites. A 1 5-year-old male presented with a conjunctival fleshy swelling near the inner canthus of the left eye. His visual acuity was within normal range. Conjunctival papilloma was the provisional diagnosis for which he was operated on. Histopathology proved to be a case of ocular rhinosporidiosis. Six months follow-up of the case showed no recurrence.