A Conjugated Polymer-based Portable Smartphone Platform for Sensitive and Point-of-Care Detection of Monoamine Neurotransmitter┴.

The precise and effective detection of neurotransmitters (NTs) is crucial for clinical investigation of neuronal processes, and timely monitoring of NT-related chronic diseases. However, sensitive detection of specific NT with unprecedented selectivity is highly challenging due to similarities in chemical and electronic structures of various interfering neurochemicals. Herein, an anionic conjugated polyelectrolyte Poly[(9,9-bis(4'-sulfonatobutyl)fluorene-co-alt-1,4-phenylene) sodium], PFPS was rationally designed and synthesized for amplified detection and point-of-care (PoC) determination of monoamine neurotransmitter, serotonin (5-Hydroxy tryptamine or 5-HT, also diagnostic biomarker of carcinoid tumor) in human blood plasma. The PFPS displayed a remarkable sensing response with an exceptionally high fluorescence quenching constant of 1.14 × 105 M-1 and an ultralow detection limit of 0.67 µM or 0.142ppm, much below the clinical range (0.5-1.4 µM). Furthermore, a smartphone-enabled portable platform was constructed for real-time onsite detection of 5-HT by quantification of visual fluorescence response of PFPS into RGB values using a color recognizer android application. The smartphone platform could be readily applied for convenient, non-invasive PoC testing of 5-HT levels in complex biological fluids accurately and is expected to revolutionize clinical diagnosis and personalized health care devices.

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. These outcomes involving dual sensing mechanistic pathways expand the scope of developing efficient sensing probes for toxic chemical analyte and biomarker detection, preventing environmental pollution and strengthening security at sensitive locations while assisting in early diagnosis of disease biomarkers.

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). Thus, these luminescent materials extended the utility in sensing, imaging, optoelectronics and theranostic applications in biological field over the conventional fluorescent probe. Unlike the sensitivity of triplet state by oxygen and moisture, the long-lived phosphorescence and delayed fluorescence resulting from the enhanced intersystem crossing (ISC) and reverse intersystem crossing (RISC) from excited triplet state (T1) to excited singlet state (S1) in these luminophores gives rise to long lifetimes ranging from nanoseconds to milliseconds even up to seconds. As compared to traditional fluorescence molecules advanced AIE probes show high contrast imaging and deeper penetration depth, which have been demonstrated through near infrared I and II (NIR-I & NIR-II) fluorescence imaging, room temperature after-glow imaging and photoacoustic imaging. This chapter highlights the recent developments and principle of the efficient design of AIE probe with multi-functional properties evolved with new strategies for translational applications via fluorescence imaging, photoacoustic imaging and image-guided photodynamic/photothermal therapy (PDT/PTT) including future opportunities for AIEgens to advance the overall biomedical field.

RETRACTED: Anisotropic (spherical/hexagon/cube) silver nanoparticle embedded magnetic carbon nanosphere as platform for designing of tramadol imprinted polymer.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief following concerns raised by a reader. The particles shown in Fig. 3F appear to be copies of each other as they share the identical arrangement of the characteristic speckles inside the particles. In addition, the extraordinary similarities observed between the data presented in Fig. 4C and in Fig. 3C in ACS Biomater. Sci. Eng., 2017, 3 (9), pp 2120­2135, 10.1021/acsbiomaterials.7b00089, Fig. 4A in Colloids and Surfaces B: Biointerfaces, Volume 142, 1 June 2016, Pages 248-258 10.1016/j.colsurfb.2016.02.053 and Fig. 1D in Biosensors and Bioelectronics, Volume 73, 15 November 2015, Pages 234-244, 10.1016/j.bios.2015.06.005 are highly unlikely. The problems with the data presented cast doubt on all the data, and accordingly also the conclusions based on that data, in this publication. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.