vishal kachwal
@eng.ox.ac.uk
Postdoctoral Research Assistant, Department of Engineering Science (Professor -Jin Chong Tan)
Department of Engineerign Science, University of Oxford
Vishal Kachwal graduated with honors from Chaitanya Post Graduate College, Deemed to be University, Hanamkonda, Warangal, Telangana (India) in 2014. He received his Ph.D. in 2020 from BITS Pilani, Pilani, under the supervision of Prof. Inamur Rahaman Laskar, on solid luminescent stimuli-responsive materials. He then becomes a postdoctoral researcher in the Department of Engineering Science at Oxford University since July 2021. Recent research includes fabrication of AIE-hybridized MOFs and electrospun nanofiber composites for sensing applications.
EDUCATION
PhD (Doctor of Philosophy) in Chemistry August 2014-Dec 2020- Birla Institute of Technology and Science (BITS-Pilani) Pilani, Rajasthan, India,
5 Years M.Sc Integrated Chemistry August 2009- May 2014 -Chaitanya Post Graduate College-Autonomous (Kakatiya University), Hanamkonda, Waranga
RESEARCH, TEACHING, or OTHER INTERESTS
Multidisciplinary, Inorganic Chemistry, Analytical Chemistry, General Chemistry
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Vishal Kachwal, Samraj Mollick, and Jin‐Chong Tan
Wiley
AbstractAdvances in energy‐efficient lighting and display technologies demand innovative materials with tailored broad‐spectrum emission properties. Hybrid aggregation‐induced emission metal‐organic frameworks (AIE‐MOFs) offer a promising avenue, combining unique characteristics of organic and inorganic components to yield enhanced luminescence efficiency and robust material stability. The study introduces a spectrum of D (donor)‐A (acceptor) type AIE‐active ligands into MOFs, enabling tunable emission across the visible spectrum, thus underscoring the versatility of these hybridized MOF materials. The emission properties of AIE‐MOFs are further harnessed by integrating them into polymer matrices, resulting in high‐performance electrospun fibers with tunable emission. A significant achievement involves the fabrication of Janus‐type white light‐emitting AIE‐MOF fiber composites via side‐by‐side electrospinning, accomplishing a high quantum yield of 58%, which doubled the performance of homogeneous fibers. Complementing the experimental findings, micro‐Raman and nano‐Fourier transform infrared spectroscopy are employed as local spectroscopic probes, affording a deeper understanding of the material properties and the mechanisms contributing to enhance light emission. In the understanding, this study presents an unconventional implementation of hybrid AIE‐MOFs in Janus‐type structures for white light emission. It significantly improves the efficiency of white light sources in optoelectronics, charting a promising direction for future research in the emergent AIE‐MOF field.
Samraj Mollick, Sujeet Rai, Louis Frentzel‐Beyme, Vishal Kachwal, Lorenzo Donà, Dagmar Schürmann, Bartolomeo Civalleri, Sebastian Henke, and Jin‐Chong Tan
Wiley
AbstractDespite exhaled human breath having enabled noninvasive diabetes diagnosis, selective acetone vapor detection by fluorescence approach in the diabetic range (1.8–3.5 ppm) remains a long‐standing challenge. A set of water‐resistant luminescent metal‐organic framework (MOF)‐based composites have been reported for detecting acetone vapor in the diabetic range with a limit of detection of 200 ppb. The luminescent materials possess the ability to selectively detect acetone vapor from a mixture comprising nitrogen, oxygen, carbon dioxide, water vapor, and alcohol vapor, which are prevalent in exhaled breath. It is noteworthy that this is the first luminescent MOF material capable of selectively detecting acetone vapor in the diabetic range via a turn‐on mechanism. The material can be reused within a matter of minutes under ambient conditions. Industrially pertinent electrospun luminescent fibers are likewise fabricated alongside various luminescent films for selective detection of ultratrace quantities of acetone vapor present in the air. Ab initio theoretical calculations combined with in situ synchrotron‐based dosing studies uncovered the material's remarkable hypersensitivity toward acetone vapor. Finally, a freshly designed prototype fluorescence‐based portable optical sensor is utilized as a proof‐of‐concept for the rapid detection of acetone vapor within the diabetic range.
Ram Prasad Bhatta, Annu Agarwal, Vishal Kachwal, Pramod C. Raichure, and Inamur Rahaman Laskar
Royal Society of Chemistry (RSC)
Ir-complex with PMMA composite showed enhanced quantum efficiency and the large number of pores facilitating to trap TNT vapors effectively, thus improved sensitivity.
Samraj Mollick, Yang Zhang, Waqas Kamal, Michele Tricarico, Annika F. Möslein, Vishal Kachwal, Nader Amin, Alfonso A. Castrejón-Pita, Stephen M. Morris, and Jin-Chong Tan
Elsevier BV
Annu Agarwal, Ram Prasad Bhatta, Vishal Kachwal, and Inamur Rahaman Laskar
Royal Society of Chemistry (RSC)
AIE active cyclometalated complexes of iridium(iii) exhibiting high quantum yield showed selective and sensitive detection of TNT and TNP explosives through rationally choosing the appropriate electronic substituents on the cyclometalated ligand.
Ram Prasad Bhatta, Vishal Kachwal, Clàudia Climent, Mayank Joshi, Pere Alemany, A. Roy Choudhury, and Inamur Rahaman Laskar
Royal Society of Chemistry (RSC)
This research article presents a novel method for achieving tunable colours (blue to red) from a single organic fluorophore. Emission tuning is associated with different self-assembled structures and aggregates size controlled by reaction time.
Sumit, Kavya Sree Maravajjala, Simran Khanna, Vishal Kachwal, Karnam Laxmi Swetha, Santosh Manabala, Rajdeep Chowdhury, Aniruddha Roy, and Inamur Rahaman Laskar
American Chemical Society (ACS)
Two "aggregation-enhanced emission" (AEE) active cyclometalated phosphorescent iridium(III) complexes, SM2 and SM4, were synthesized to evaluate the influence of lipophilicity on photodynamic therapy efficacy. Compared to SM2, SM4 had a higher logP due to the presence of naphthyl groups. As observed by confocal microscopy, this increased lipophilicity of SM4 significantly enhanced its cellular uptake in breast cancer cells. Both the molecules were found to be noncytotoxic under nonirradiating conditions. However, with light irradiation, SM4 exhibited significant cytotoxicity at a 500 nM dose, whereas SM2 remained noncytotoxic, signifying the influence of lipophilicity on cellular internalization and cytotoxicity. Mechanistically, light-irradiated SM4-treated cancer cells exhibited a significant increase in the intracellular reactive oxygen species (ROS) level. Neutralizing ROS with N-acetylcysteine (NAC) pretreatment partly abolished the cytotoxic ability, indicating ROS as one of the major effectors of cell cytotoxicity. Two nanoparticle (NP) formulations of SM4 were developed to improve the intracellular delivery: a PLGA-based NP and a Soluplus-based micelle. Interestingly, PLGA and Soluplus NP formulations exhibited a 10- and 22-fold increased emission intensity, respectively, compared to SM4. There was also an increase in the excited-state lifetime. Additionally, the Soluplus-based micelles encapsulating SM4 exhibited enhanced cellular uptake and increased cytotoxicity compared to the PLGA NPs encapsulating SM4. Altogether, the current study indicates the importance of rational molecular designing and the significance of a proper delivery vector for improving photodynamic therapy efficacy.
Vishal Kachwal and Jin‐Chong Tan
Wiley
AbstractThis review addresses the latest advancements in the integration of aggregation‐induced emission (AIE) materials with polymer electrospinning, to accomplish fine‐scale electrospun fibers with tunable photophysical and photochemical properties. Micro‐ and nanoscale fibers augmented with AIE dyes (termed AIEgens) are bespoke composite systems that can overcome the limitation posed by aggregation‐caused quenching, a critical deficiency of conventional luminescent materials. This review comprises three parts. First, the reader is exposed to the basic concepts of AIE and the fundamental mechanisms underpinning the restriction of intermolecular motions. This is followed by an introduction to electrospinning techniques pertinent to AIE‐based fibers, and the core parameters for controlling fiber architecture and resultant properties. Second, exemplars are drawn from latest research to demonstrate how electrospun nanofibers and porous films incorporating modified AIEgens (especially tetraphenylethylene and triphenylamine derivatives) can yield enhanced photostability, photothermal properties, photoefficiency (quantum yield), and improved device sensitivity. Advanced applications are drawn from several promising sectors, encompassing optoelectronics, drug delivery and biology, chemosensors and mechanochromic sensors, and innovative photothermal devices, among others. Finally, the outstanding challenges together with potential opportunities in the nascent field of electrospun AIE‐active fibers are presented, for stimulating frontier research and explorations in this exciting field.
Pramod C. Raichure, Vishal Kachwal, Dineshkumar Sengottuvelu, and Inamur Rahaman Laskar
American Chemical Society (ACS)
Yang Zhang, Tao Xiong, Annika F. Möslein, Samraj Mollick, Vishal Kachwal, Arun Singh Babal, Nader Amin, and Jin-Chong Tan
Elsevier BV
Pramod C. Raichure, Ramprasad Bhatt, Vishal Kachwal, Tirupati Chander Sharma, and Inamur Rahaman Laskar
Royal Society of Chemistry (RSC)
P1 shows distinct emission responses with multi-stimuli, i.e., quenching for TNT sensing, red shifting for acid and base vapors, blue shifting against MFC behavior, and solvent polarity-dependent emission.
Pramod C. Raichure, Vishal Kachwal, and Inamur Rahaman Laskar
MDPI AG
Selective vapor-phase detection of dichloromethane (DCM) is a challenge, it being a well-known hazardous volatile organic solvent in trace amounts. With this in mind, we have developed an ‘Aggregation-induced Emission’ (AIE) active mono-cyclometalated iridium(III)-based (M1) probe molecule, which detects DCM sensitively and selectively in vapor phase with a response time <30 s. It reveals a turn-on emission (non-emissive to intense yellow) on exposing DCM vapor directly to the solid M1. The recorded detection limit is 4.9 ppm for DCM vapor with pristine M1. The mechanism of DCM detection was explored. Moreover, the detection of DCM vapor by M1 was extended with a low-cost filter paper as the substrate. The DCM is weakly bound with the probe and can be removed with a mild treatment, so, notably, the probe can be reused.
Vishal Kachwal and Inamur Rahaman Laskar
Springer Science and Business Media LLC
Vishal Kachwal, Abhilasha Srivastava, Sumukh Thakar, Maria Zubiria-Ulacia, Diplesh Gautam, Syamantak Majumder, Venkatesh K. P., David Casanova, Rajdeep Chowdhury, Nigam Rath,et al.
Royal Society of Chemistry (RSC)
Engineering a photo isomerized cyanine based molecular rotor to enhance the sensitivity towards the viscosity of the medium: an efficient tool for differentiating abnormal cells by restriction of the internal motion.
Dineshkumar Sengottuvelu, Vishal Kachwal, Pramod Raichure, Tarun Raghav, and Inamur Rahaman Laskar
American Chemical Society (ACS)
The article reports a straightforward strategy for the design and synthesis of highly luminescent conjugated mesoporous oligomers (CMOs) with 'Aggregation- induced enhanced emission' (AIEE) feature through Wittig polymerization of the molecular rotor. Typical molecular rotors such as triphenylamine (TPA) and tetraphenylethene (TPE) as B2, A4 & A3 type nodes have been used to construct AIEE active CMOs, namely CMO1 & CMO2. The quick dissipation of the excited photons was successfully controlled by the restriction of rotation of the phenyl units through the formation of the mesoporous network scaffold in solid/thin film, which provides the high quantum yields for the interlocked CMOs system. Both the CMOs are sensitive and selective to the various nitroaromatics based explosives, whereas CMO1 is more sensitive (Ksv = 2.6 × 106 M-1) towards the picric acid. The increased quenching constant for CMO1 is due to its increased quantum yield and high-energy transfer efficiency. The mechanism for sensing has been studied in detail. The larger pore size and pore density in the mesoporous network of CMO1 are found to be responsible for the greater extent of energy transfer from CMO1 to picric acid. Furthermore, CMO1 has been employed for low-cost filter paper-based detection of trace nitroaromatic containing explosive materials.
Vishal Kachwal, Parva Kumar Sharma, Amrit Sarmah, Shibasish Chowdhury, and Inamur Rahaman Laskar
Royal Society of Chemistry (RSC)
This article focuses on the vital role of hydrogen bonding to explain unusual photophysical behaviours (sensing BSA, pH probing, specific solvent effect) of an ‘Aggregation-induced Emission’ (AIE) active Ir(iii) complex.
Sengottuvelu Dineshkumar, Abhishek Raj, Abhilasha Srivastava, Sudeshna Mukherjee, Sheik Saleem Pasha, Vishal Kachwal, Leena Fageria, Rajdeep Chowdhury, and Inamur Rahaman Laskar
American Chemical Society (ACS)
Typical AIE luminogens tetraphenylethene (TPE) and triphenylamine (TPA) have been used to construct AIE active conjugated polymer namely Poly(N,N-diphenyl-4-(4-(1,2,2-triphenylvinyl)styryl)aniline)) (PTPA), which consist of D-π-A architecture by Wittig polymerization. We fabricated mesoporous silica hollow nanospheres (MSHNs) which were encapsulated with AIE active polymer for applications in cellular imaging. It exhibits positive solvatochromism effect by increasing solvent polarity, supported by theoretical calculation using density functional theory (DFT). The structure of the monomers and polymer was confirmed by FT-IR, NMR and HRMS techniques. With considering the advantage of high brightness in fluorescence of PTPA, it was encapsulated into MSHNs by non-covalent approach and surface was functionalized with anti-EpCAM (Epithelial cell adhesion molecule) aptamer through conjugation with γ-glycidoxypropyltrimethoxysilane (GTMS) for targeting cancer cells specifically. Aptamer functionalized Apt-MSHNs exhibited excellent biocompatibility with the liver cancer- Huh-7 cells used for this study and was efficiently internalized by these cells. Since, EpCAM are over-expressed in multiple carcinomas, including liver cancer, these aptamer conjugated AIE MSHNs are therefore good candidates for targeted cellular imaging applications.
Vishal Kachwal, Mayank Joshi, Vibhor Mittal, Angshuman Roy Choudhury, and Inamur Rahaman Laskar
Elsevier BV
Vishal Kachwal, I. S. Vamsi Krishna, Leena Fageria, Jagrity Chaudhary, Ram Kinkar Roy, Rajdeep Chowdhury, and Inamur Rahaman Laskar
Royal Society of Chemistry (RSC)
The hidden potential of an AIE-ESIPT active, simple substituted benzothiazole compound has been explored.
Vishal Kachwal, Parvej Alam, Hare Ram Yadav, Sheik Saleem Pasha, Angshuman Roy Choudhury, and Inamur Rahaman Laskar
Royal Society of Chemistry (RSC)
A simple and efficient pyrene based luminescent multifunctional probe was utilized in selective and sensitive ratiometric detection of H+, Al3+ and picric acid.
Parvej Alam, Vishal Kachwal, and Inamur Rahaman Laskar
Elsevier BV
Parvej Alam, Gurpreet Kaur, Vishal Kachwal, Asish Gupta, Angshuman Roy Choudhury, and Inamur Rahaman Laskar
Royal Society of Chemistry (RSC)
Two phosphorescent complexes [Ir(o-CHOppy)(PPh3)2(H)Cl] (1) and [Ir(ppy)(PPh3)2(H)Cl] (2) exhibiting ‘aggregation induced phosphorescent emission (AIPE)’ properties have been found to be very sensitive to the detection of picric acid (PA).