Sandeepa Kulala Vittala

Ordered assembly of fullerenes is of significant importance in organic electronic applications, as charge carrier mobility in fullerene-based materials is highly sensitive to structural order. However, commonly employed solution-processing techniques often suffer from strong aggregation tendencies or uncontrolled crystallization of fullerenes during film formation. In contrast, advanced nanofabrication techniques that enable precise control over fullerene morphology at the nanoscale are typically complex and costly. In this work, we propose a facile supramolecular strategy based on the polymer-assisted assembly of a pyridinium-functionalized fullerene amphiphile (FPy) to achieve ordered fullerene architectures, thereby enhancing charge carrier mobility through reduced energetic disorder. A commercially available anionic polymer, polystyrenesulfonate (PSS), was employed to assemble the cationic fullerene derivative (FPy) primarily via electrostatic interactions, further stabilized by π–π stacking between fullerene units. The interaction of FPy with PSS was confirmed by UV–visible absorption spectroscopy, while TEM, SEM, and AFM analyses revealed the formation of ultrathin two-dimensional crystalline nanosheets with highly ordered fullerene packing. X-ray diffraction (XRD) analyses clearly demonstrate a transition from polycrystalline FPy to a highly ordered and uniform face-centered cubic (FCC) lattice in the PSS/FPy hybrid, confirming the anionic polymer-induced switching toward a more ordered nanoassembly. Space-charge-limited current (SCLC) measurements further revealed an order-of-magnitude enhancement in electron mobility (0.92 × 10–3 cm2 V–1 S–1) compared to FPy alone, which can be correlated with the reduced energetic disorder in the FCC lattice structure of the PSS/FPy hybrid assembly. Overall, this study highlights the significance of polymer-assisted assembly of rationally designed amphiphilic fullerenes as a general and scalable strategy to improve electron transport in a wide range of optoelectronic devices.

Covalent modification of proteins at specific, predetermined sites is essential for advancing biological and biopharmaceutical applications. Site-selective labeling techniques for protein modification allow us to effectively track biological function, intracellular dynamics, and localization. Despite numerous reports on modifying target proteins with functional chemical probes, unique organic reactions that achieve site-selective integration without compromising native functional properties remain a significant challenge. In this review, we delve into site-selective protein modification using synthetic probes, highlighting both chemical and computational methodologies for chemo- and regioselective modifications of naturally occurring amino acids, as well as proximity-driven protein-selective chemical modifications. We also underline recent traceless affinity labeling strategies that involve exchange/cleavage reactions and catalyst tethering modifications. The rapid development of computational infrastructure and methods has made the bioconjugation of proteins more accessible, enabling precise predictions of structural changes due to protein modifications. Hence, we discuss bioconjugational computational approaches, including molecular dynamics and artificial intelligence, underscoring their potential applications in enhancing our understanding of cellular biology and addressing current challenges in the field.

The synthesis, optoelectronic characterization and device properties of a cross‐linkable fullerene derivative, [6,6]‐phenyl‐C₆₁‐butyric benzoxazine ester (PCBB) is reported. PCBB shows all the basic photophysical and electrochemical properties of the parent compound [6,6]‐phenyl‐C₆₁‐butyric methyl ester (PCBM). Thermal cross‐linking of the benzoxazine moiety in PCBB resulted in the formation of cross‐linked, solvent resistive adhesive films (C−PCBB). Atomic force microscopy (AFM) and optical microscopic studies showed dramatic reduction in the roughness and aggregation behaviour of P3HT‐PCBM polymer blend film upon incorporation of C−PCBB interlayer. An inverted bulk heterojunction solar cell based on the configuration ITO/ZnO/C−PCBB/P3HT‐PCBM/V₂O₅/Ag achieved 4.27 % power conversion efficiency (PCE) compared to the reference device ITO/ZnO/P3HT‐PCBM/V₂O₅/Ag (PCE=3.28 %). This 25 % increase in the efficiency is due to the positive effects of C‐PCBB on P3HT/C‐PCBB and PCBM/C‐PCBB heterojunctions.

Programmable DNA-guided self-assembly of nanoscale functional materials is of great interest in the context of nanofabrication or nanoelectronics. Attributed to its unique sequence programmability and precisely defined dimension, DNA has been used as a template for constructing ordered 1D, 2D and 3D architectures with organic, inorganic and polymeric building blocks via various self-assembly strategies. Moreover, the accessible integration capability of DNA with diverse electronics-related materials propels the field of DNA-guided assemblies towards nanoelectronic applications. In this review, we outline the development in the area of DNA-guided assemblies that are constructed from carbon nanotubes, fullerenes, polymers, metals, metal oxides, minerals using various strategies, with the focus on the bottom-up DNA-guided conducting, semiconducting and insulating nanomaterials applied on nanoelectronics. We also review some bottom-up and top-down hybrid methods that precisely immobilize functional DNA-guided materials on substrates with high throughput. Finally, we describe the challenges in nanofabrication and potential applications of DNA-guided assemblies in nanoelectronics.

Programmable construction of two dimensional (2D) nanoarchitectures using short DNA strands is of utmost interest in the context of DNA nanotechnology. Previously, we have demonstrated fullerene-cluster assisted self-assembly of short oligonucleotide duplexes into micrometer long, semiconducting nanowires. This report demonstrates the construction of micrometer-sized nanosheets and 2D-nanonetworks from the mutual self-assembly of fullerene nanoclusters with three way junction DNA (3WJ-DNA) and 3WJ-DNA with a 12-mer overhang (3WJ-OH), respectively. The interaction of unique sized fullerene clusters prepared from an aniline appended fullerene derivative, F-An, with two 3WJ-DNAs, namely, 3WJ-20 and 3WJ-30, having 20 and 30 nucleobases, respectively at each strand was characterized using UV-visible absorption, circular dichroism and fluorescence techniques. The morphological characterization of nanosheets embedded with F-An clusters was performed via AFM, TEM and DLS analyses. The programmability and structural tunability of the resultant nanostructures were further demonstrated using 3WJ-OH containing a cytosine rich, single stranded DNA 12-mer overhang, which forms entangled 2D-nanonetwork structures instead of nanosheets due to the differential interaction of F-An nanoclusters with single and duplex strands of 3WJ-OH. Moreover, the selective modification of the cytosine rich sequence present in 3WJ-OH with silver nanoclusters (AgNCs) resulted in significant enhancement in silver nanocluster fluorescence (∼40%) compared to 3WJ-OH/AgNCs owing to the additional stability of AgNCs embedded in 2D nanostructures. This unique strategy of constructing DNA based 2D nanomaterials and their utilization in the integration of functional motifs could find application in the area of DNA nanotechnology and bio-molecular sensing.

Recent developments in the area of functional supramolecular materials fabricated via the self-assembly of fullerene derivatives and DNA are discussed. Emphasis is given to different modes of DNA-fullerene interactions, fullerene-induced DNA condensation, and higher-order nanostructures, including fullerene cluster-assisted DNA assemblies. We also review various applications of these fullerene-DNA hybrid nanostructures reported in recent years, with a special focus on optoelectronic and biomedical applications. 272Finally, in the outlook, we describe the prospects of fullerene-assisted DNA nanostructures in DNA nanotechnology, material science, and molecular electronics.

Programmable, hierarchical assembly of DNA nanostructures with precise organisation of functional components have been demonstrated previously with tiled assembly and DNA origami. However, building organised nanostructures with random oligonucleotide strands remains as an elusive problem. Herein, a simple and general strategy, in which nanoclusters of a fullerene derivative act as stapler motifs in bringing ordered nanoscale assembly of short oligonucleotide duplexes into micrometre‐sized nanowires, is described. In this approach, the fullerene derivative, by virtue of its amphiphilic structure and unique hydrophobic–hydrophilic balance, pre‐assembles to form 3–5 nm sized clusters in a mixture of DMSO–phosphate buffer, which further assists the assembly of DNA strands. The optimum cluster size, availability of DNA anchoring motifs and the nature of the DNA strands controls the structure of these nanomaterials. Furthermore, horizontal conductivity measurements through conductive AFM confirmed the charge transport properties of these nanowires. The current strategy could be employed to organise random DNA duplexes and tiles into functional nanostructures, and hence, open up new avenues in DNA nanotechnology.