Multifunctional hydroxyquinoline-derived turn-on fluorescent probe for Alzheimer's disease detection and therapy.

Understanding molecular motifs that can interfere with amyloid fibrillation through non-covalent interactions is essential for addressing abnormal protein aggregation and associated human diseases. The pursuit of efficient diagnostic and treatment approaches for Alzheimer's disease (AD) has resulted in the development of M8HQ, a multifaceted small molecule turn-on probe derived from 8-hydroxyquinoline with versatile capabilities. M8HQ shows a strong affinity for amyloid beta (Aβ) fibrils, and its ability to target lysosomes enhances therapeutic precision by localizing within these organelles.

Minimizing defect states through multidentate coordination and morphology regulation for enhancing the performance of inverted perovskite solar cells.

The diversity of the defects present in perovskite materials negatively impacts both the power conversion efficiency (PCE) and the long-term stability of perovskite solar cells (PSCs). The chemical passivation of these defects has been addressed through a multifunctional molecule, 4-((trifluoromethyl)thio)benzoic acid, that contains the carbonyl (CO) group, which exhibits a strong passivation effect by interacting with both the organic cation (FA) and uncoordinated Pb ionic defects while the sulfur (S) heteroatom passivates Pb defects at the grain boundary and on the surfaces of the perovskite layer. Additionally, the CF group protects the perovskite film from ambient degradation as well as stabilizing the perovskite framework by forming hydrogen and coordination bonds with the FA cation and Pb ions, respectively.

Bi-Directional Modification to Quench Detrimental Redox Reactions and Minimize Interfacial Energy Offset for NiO/Perovskite-Based Solar Cells.

The quality of the buried heterojunction of nickel oxide (NiO)/perovskite is crucial for efficient charge carrier extraction and minimizing interfacial non-radiative recombination in inverted perovskite solar cells (PSCs). However, NiO has limitations as a hole transport layer (HTL) due to energy level mismatch, low conduction, and undesirable redox reactions with the perovskite layer, which impede power conversion efficiency (PCE) and long-term stability. In this study, para-amino 2,3,5,6-tetrafluorobenzoic acid (PATFBA) is proposed as a bifacial defect passivator to tailor the NiO/perovskite interface.

Sulphur-atom positional engineering in perylenimide: structure-property relationships and H-aggregation directed type-I photodynamic therapy.

An innovative design strategy of placing sulfur (S)-atoms within the pendant functional groups and at carbonyl positions in conventional perylenimide (PNI-O) has been demonstrated to investigate the condensed state structure-property relationship and potential photodynamic therapy (PDT) application. Incorporation of simply S-atoms at the -functionalized perylenimide (RPNI-O) leads to an aggregation-induced enhanced emission luminogen (AIEEgen), 2-hexyl-8-(thianthren-1-yl)-1-benzo[5,10]anthra[2,1,9-def]isoquinoline-1,3(2)-dione (API), which achieves a remarkable photoluminescence quantum yield ( ) of 0.85 in aqueous environments and established novel AIE mechanisms.

Substitution effects on the photoinduced excited state dynamics of perylenemonoimides in solution and thin films.

Perylene monoimide (PMI) derivatives are attracting significant attention due to their strong absorption in the visible range, thermal stability, and synthetic accessibility. These properties make them promising for application in various areas such as optoelectronic devices, photosensitizers, In this work, the photophysical properties and excited state dynamics of four different PMI derivatives (PMIB, BrPMITB, PMITB, and APITB) were studied in solution and thin films utilizing steady-state and time-resolved spectroscopic techniques. Among the four PMI derivatives, APITB is designed as a donor-acceptor dyad, with thianthrene as a donor and PMI as an acceptor.

Activating Ion Channels in Collapsed Hydrogel Derived Densified MXene Films with Cellulose Nanofibers to Overcome the Areal Versus Volumetric Capacitance Trade-Off.

Concomitant achievement of all three performance pillars of a supercapacitor device, namely gravimetric, areal, and volumetric capacitance is a grand challenge. Nevertheless, its fulfilment is indispensable for commercial usage. Although, high compactness is the fundamental requirement to achieve high volumetric performance, it severely affects ion transportation in thick electrodes.

Ambient stable solution-processed organic field effect transistors from electron deficient planar aromatics: effect of end-groups on ambient stability.

Ambient stable solution processed n-channel organic field effect transistors (OFETs) are essential for next-generation low-cost organic electronic devices. Several molecular features, such as suitable orbital energy levels, easy synthetic steps, , must be considered while designing efficient active layer materials. Here, we report a case of improved ambient stability of solution-processed n-type OFETs upon suitable end-groups substitution of the active layer materials.

Role of Amyloid Beta in Neurodegeneration and Therapeutic Strategies for Neuroprotection.

The gradual loss of neurons' structure and function in the central nervous system is known as neurodegeneration. It is a defining feature of several incapacitating illnesses, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. The buildup of amyloid beta (Aβ) protein in the brain is one of the several variables linked to neurodegeneration.

Through-Space Charge-Transfer-Based Aggregation-Induced Emission and Thermally Activated Delayed Fluorescence in Fused 2H-Chromene Coumarin Congener Generating ROS for Antiviral (SARS-CoV-2) Approach.

Harvesting triplets in metal-free organic frameworks at ambient conditions and finding appropriate applications are a formidable challenge. Herein, we report a donor-acceptor-type system composed of carbazole and fused 2-chromene coumarin derivative, exhibiting triplet harvesting thermally activated delayed fluorescence (TADF) and aggregation-induced emission (AIE) behavior in solid and aggregated states, respectively. The presence of an sp linker and the introduction of a selected cyano/ester group in the acceptor result in twisted D-A architectures, further assisting in the suppression of nonradiative deactivation via through-space charge transfer and H-bonding interactions, fulfilling the stringent requirements for the simultaneous process of TADF and AIE, successively.

Amyloid Targeting Red Emitting AIE Dots for Diagnostic and Therapeutic Application against Alzheimer's Disease.

The emergence of neurodegenerative diseases is connected to several pathogenic factors, including metal ions, amyloidogenic proteins, and reactive oxygen species. Recent studies suggest that cytotoxicity is caused by the small, dynamic, and metastable nature of early stage oligomeric species. This work introduces a small molecule-based red-emitting probe with smart features such as increased reactivities against multiple targets, metal-free amyloid-β (Aβ), and metal-bound amyloid-β (Aβ), and most importantly, early stage oligomeric species which are associated with the most common and widespread type of dementia, Alzheimer's disease (AD).

Improved Efficiency and Stability in 1,5-Diaminonaphthalene Iodide-Passivated 2D/3D Perovskite Solar Cells.

Engineering multidimensional two-dimensional/three-dimensional (2D/3D) perovskite interfaces as light harvesters has recently emerged as a potential strategy to obtain a higher photovoltaic performance in perovskite solar cells (PSCs) with enhanced environmental stability. In this study, we utilized the 1,5-diammonium naphthalene iodide (NDAI) bulky organic spacer for interface modification in 3D perovskites for passivating the anionic iodide/uncoordinated Pb vacancies as well as facilitating charge carrier transfer by improving the energy band alignment at the perovskite/HTL interface. Consequently, the NDAI-treated 2D/3D PSCs showed an enhanced open-circuit voltage and fill factor with a remarkable power conversion efficiency (PCE) of 21.

A water-soluble conjugated polyelectrolyte for selective and sensitive detection of carcinogenic chromium(VI).

Environmental water pollution caused by hexavalent chromium (Cr(VI)) is a threat to living beings due to its carcinogenic nature. Herein, we report the synthesis of a highly fluorescent water-soluble conjugated polyelectrolyte PPMI and its application as a fluorescence sensor to monitor traces of carcinogenic Cr(VI) ions in water. PPMI was synthesized the oxidative polymerization method followed by post-polymer functionalization.

Highly efficient color-tunable organic co-crystals unveiling polymorphism, isomerism, delayed fluorescence for optical waveguides and cell-imaging.

Photofunctional co-crystal engineering strategies based on donor-acceptor π-conjugated system facilitates expedient molecular packing, consistent morphology, and switchable optical properties, conferring synergic 'structure-property relationship' for optoelectronic and biological functions. In this work, a series of organic co-crystals were formulated using a twisted aromatic hydrocarbon (TAH) donor and three diverse planar acceptors, resulting in color-tunable solid and aggregated state emission via variable packing and through-space charge-transfer interactions. While, adjusting the strength of acceptors, a structural transformation into hybrid stacking modes ultimately results in color-specific polymorphs, a configurational cis-isomer with very high photoluminescence quantum yield.

Self-Assembly Driven Formation of Functional Ultralong "Artificial Fibers" to Mitigate the Neuronal Damage Associated with Alzheimer's Disease.

Fibrillation of amyloid beta (Aβ) is the key event in the amyloid neurotoxicity process that induces a chain of toxic events including oxidative stress, caspase activation, poly(ADP-ribose) polymerase cleavage, and mitochondrial dysfunction resulting in neuronal loss and memory decline manifesting as clinical dementia in humans. Herein, we report the development of a novel, biologically active supramolecular probe, INHQ, and achieve functional nanoarchitectures via a self-assembly process such that ultralong fibers are achieved spontaneously. With specifically decorated functional groups on INHQ such as imidazole, hydroxyquinoline, hydrophobic chain, and hydroxyquinoline molecules, these ultralong fibers coassembled efficiently with toxic Aβ oligomers and mitigated the amyloid-induced neurotoxicity by blocking the aforementioned biochemical events leading to neuronal damage in mice.

Hot-exciton harvesting through-space single-molecule based white-light emission and optical waveguides.

Through-space donor-alkyl bridge-acceptor (D-σ-A) luminogens are developed as new organic single-molecule white light emitters (OSMWLEs) involving multiple higher lying singlet (S ) and triplet (T ) states (hot-excitons). Experimental and theoretical results confirm the origin of white light emission due to the co-existence of prompt fluorescence from locally excited states, thermally activated delayed fluorescence (TADF), and fast/slow dual phosphorescence color mixing simultaneously. Notably, the fast phosphorescence was observed due to trace amounts of isomeric impurities from commercial carbazole, while H-/J-aggregation resulted in slow phosphorescence.

Aggregation and Binding-Directed FRET Modulation of Conjugated Polymer Materials for Selective and Point-of-Care Monitoring of Serum Albumins.

Nonspecific interactions of conjugated polymers (CPs) with various proteins prove to be a major impediment for researchers when designing a suitable CP-based probe for the amplified and selective recognition of particular proteins in complex body fluids. Herein, a new strategy is presented for the precise and specific monitoring of clinically important serum albumin (SA) proteins at the nanomolar level using fluorescence resonance energy transfer (FRET)-modulated CP-surfactant ensembles as superior sensing materials. In brief, the newly designed color-tunable CP PF-DBT-Im undergoes intense aggregation with the surfactant sodium dodecyl sulfate (SDS), enabling drastic change in the emission color from violet to deep red due to intermolecular FRET.

Wearable Sensing Devices for Point of Care Diagnostics.

The growth of smart wearable sensing systems has gained immense importance in the present mode of data acquisition and signaling in pharmaceutical, healthcare, and wellness industries. Presently, application of smart wearables is gaining prominence in several fitness activities, therapeutics, and diagnostic areas. Smart wearable biosensors offer real-time monitoring of physiological metrics and biomarkers that are specific to certain diseases in ambulant condition.

Aggregation induced bright organic luminogens: Design strategies, advanced bio-imaging and theranostic applications.

The concept of aggregation-induced emission (AIE) in purely organic luminescent molecules has drawn wide attention in the last two decades. Despite the many challenges, AIE-probes have opened versatile opportunities in many research fields. In particular, the emerging functional properties of room temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) have boosted the unique features of AIE luminogens (AIEgens).

AIE active polymers for biological applications.

The discovery of aggregation-induced emission (AIE) phenomenon, significantly altered the understanding of the scientific world about the luminophore aggregation. Polymers with AIE features have recently emerged as promising materials with wide range of applications in optoelectronics devices, chemosensors, bioimaging, cancer theranostics and drug delivery. By introducing the AIE active molecule into the polymer structure, novel materials encompassing the characteristics properties of both the functional materials such as excellent brightness, versatile structure modification, high biocompatibility, exceptional stability and facile processability are achieved.

Dual "Static and Dynamic" Fluorescence Quenching Mechanisms Based Detection of TNT via a Cationic Conjugated Polymer.

A rare combination of dual static and dynamic fluorescence quenching mechanisms is reported, while sensing the nitroexplosive trinitrotoluene (TNT) in water by a cationic conjugated copolymer PFPy. Since the fluorophore PFPy interacts with TNT in both ground state as well as the excited states, a greater extent of interaction is facilitated between PFPy and the TNT, as a result of which the magnitude of the signal is amplified remarkably. The existence of these collective sensing mechanisms provides additional advantages to the sensing process and enhances the sensing parameters, such as LoD and highly competitive sensing processes in natural water bodies irrespective of the pH and at ambient conditions.

Stimuli-Responsive Trimorphs and Charge-Transfer Complexes of a Twisted Molecular Donor.

Supramolecular self-assemblies and co-assemblies possess multiple noncovalent interactions, highly ordered structures, and multifunctional properties. Yet, the fundamental understanding of their "structure-property relationship" remains very challenging. Herein, two kinetically controlled supramolecular charge transfer (CT) complexes were conceptualized from a trimorphic molecular donor denoted as "twisted aromatic hydrocarbon" (TAH), with -fluoranil (TFQ) and -chloranil (TCQ) in water, organic solvent, and solvent-free methods.

A conformational tweak for enhanced cellular internalization, photobleaching resistance and prolonged imaging efficacy.

A strategy of conformational tweaking regulates the condensed state behavior of naphthalimide skeletal isomers (NSIs) and enhances their photophysical properties, cellular uptake and prolonged imaging capability. This salient approach results in a large Stokes shift (>120 nm), rapid cellular internalization, photobleaching resistance, and efficient bioimaging of the ribbon-like nano-assembly superior to that of its electronically similar micro-flower isomer.

Amyloid Targeting "Artificial Chaperone" Impairs Oligomer Mediated Neuronal Damage and Mitochondrial Dysfunction Associated with Alzheimer's Disease.

Alzheimer's disease (AD) is an irreversible memory disorder associated with multiple neuropathological events including amyloid aggregation that triggers oxidative stress and mitochondrial dysfunction in humans. Herein, a new artificial chaperone, benzimidazole functionalized polyfluorene (PFBZ) is reported to efficiently sequester toxic amyloid beta (Aβ) by binding at their 'amyloidogenic domain' (Aβ16-21) with unprecedented selectivity and prevent amyloid-mediated neuronal damage in a wild-type (WT) mouse model. An accurate dose of PFBZ chaperone successfully attenuated an amyloid triggered internal hemorrhage and pyknosis in the cerebral cortex of WT mice.

Recent Developments on Multi-Functional Metal-Free Mechanochromic Luminescence and Thermally Activated Delayed Fluorescence Organic Materials.

Metal-free organic compounds with highly ordered π-conjugated twisted skeletons are capable of generating brilliant multi-colored light. Additionally, the co-existence of numerous other multi-functional properties have endowed them with the potential to be a promising class of materials for several electronic and photonic applications and next-generation advanced luminescent material-based devices. This review highlights the recent developments made in this fascinating class of multi-property encompassing materials, involving a highly twisted donor-acceptor based single molecular platform with synchronized photophysical behavior such as thermally activated delayed fluorescence (TADF), mechanoresponsive (MR), room-temperature phosphorescence (RTP), and aggregation induced emission (AIE) with associated unique and inherently manifested structure-property relationship investigations.

Stepwise elucidation of fluorescence based sensing mechanisms considering picric acid as a model analyte.

In most of the sensing systems, specific detection mechanisms are involved during the detection process for a certain analyte irrespective of probes. However, unlike that of various sensing analytes, the detection of the highly toxic and explosive picric acid (PA) analyte was found to involve significant types of distinct sensing mechanisms depending on the nature of probes. Moreover, in the past five years, apart from the plethora of fluorescent probes designed, a number of unique organic small molecules and polymers have been strategically developed at our laboratory for the detection of PA, wherein the involvement of several diverse mechanisms along with a few new mechanisms depending on the electronic and photophysical properties of the probes has been unveiled.