Schwarzites and Triply Periodic Minimal Surfaces: From Pure Topology Mathematics to Macroscale Applications.

Schwarzites are porous (spongy-like) carbon allotropes with negative Gaussian curvatures. They are proposed by Mackay and Terrones inspired by the works of the German mathematician Hermann Schwarz on Triply-Periodic Minimal Surfaces (TPMS). This review presents and discusses the history of schwarzites and their place among curved carbon nanomaterials. The main works on schwarzites are summarized and are available in the literature. Their unique structural, electronic, thermal, and mechanical properties are discussed. Although the synthesis of carbon-based schwarzites remains elusive, recent advances in the synthesis of zeolite-templates nanomaterials have brought them closer to reality. Atomic-based models of schwarzites are translated into macroscale ones that are 3D-printed. These 3D-printed models are exploited in many real-world applications, including water remediation and biomedical ones.

Energy Harvesting Using ZnO Nanosheet-Decorated 3D-Printed Fabrics.

In this work, we decorated piezoresponsive atomically thin ZnO nanosheets on a polymer surface using additive manufacturing (three-dimensional (3D) printing) technology to demonstrate electrical-mechanical coupling phenomena. The output voltage response of the 3D-printed architecture was regulated by varying the external mechanical pressures. Additionally, we have shown energy generation by placing the 3D-printed fabric on the padded shoulder strap of a bag with a load ranging from ∼5 to ∼75 N, taking advantage of the excellent mechanical strength and flexibility of the coated 3D-printed architecture. The ZnO coating layer forms a stable interface between ZnO nanosheets and the fabric, as confirmed by combining density functional theory (DFT) and electrical measurements. This effectively improves the output performance of the 3D-printed fabric by enhancing the charge transfer at the interface. Therefore, the present work can be used to build a new infrastructure for next-generation energy harvesters capable of carrying out several structural and functional responsibilities.

Quantifying instant water cleaning efficiency using zinc oxide decorated complex 3D printed porous architectures.

Industrialization harms the quality of water; therefore, cleaning and monitoring water sources are essential for sustainable human health and aquatic life. An increase in active surface area and porosity can result in quick and efficient cleaning activity. 3D printing can build porous architecture with controlled porosity and active surface area. Here, catalytically active ZnO nanosheets were grown on the surface of 3D printed architecture (Schwarzites and Weissmuller) with different porosity and surface area. The Weissmuller structure along with ZnO, has shown better catalytic performance due to its higher porosity (~69%) and high active surface area, compared to Schwarzites structure. Synergistic effect of adsorption and photodegradation has resulted in ~95% removal efficiency of mixed dye within 10 min by Weissmuller structure. The dye degradation efficiency was determined using colorimetric measurements with a regular smartphone for real-time quantitative investigation of dye removal efficiency. Most importantly, decorated 3D printed structures exhibit high structural stability without residuals (ZnO nanosheets) in water after performing the recycling experiment. Therefore, the decorated 3D printing structures and colorimetric detection method will offer a user-friendly versatile technique for analysis of removal efficiency of toxic components in different polluted water sources without using high-end sophisticated instruments and complicated procedures.

Development of a schwarzite-based moving bed 3D printed water treatment system for nanoplastic remediation.

The impact of micro and nanoplastic debris on our aquatic ecosystem is among the most prominent environmental challenges we face today. In addition, nanoplastics create significant concern for environmentalists because of their toxicity and difficulty in separation and removal. Here we report the development of a 3D printed moving bed water filter (M-3DPWF), which can perform as an efficient nanoplastic scavenger. The enhanced separation of the nanoplastics happens due to the creation of a charged filter material that traps the more surface charged nanoparticles selectively. Synthetic contaminated water from polycarbonate waste has been tested with the filter, and enhanced nanoplastic removal has been achieved. The proposed filtration mechanism of surface-charge based water cleaning is further validated using density function theory (semi-empirical) based simulation. The filter has also shown good structural and mechanical stability in both static and dynamic water conditions. The field suitability of the novel treatment system has also been confirmed using water from various sources, such as sea, river, and pond. Our results suggest that the newly developed water filter can be used for the removal of floating nanoparticles in water as a robust advanced treatment system.

Electrospun nanofiber-based cancer sensors: A review.

Cancer is a malignancy engendering enormous global mortality, steering extensive research for early diagnosis and efficacious prognosis leading to emergence of cancer sensing technologies for multitudinous biomarkers. In this context, nanofibers, imparting high surface area, facile production, morphology control, and synergistic properties attainable, are poised to be inevitable in futuristic sensing devices for predictive diagnostics when integrated with artificial intelligence and machine learning. To this end, fundamentals governing the sensor response and their analytical performance have been discussed. The headways in organic and inorganic nanofibers for biomarker gas sensing, fluid sample sensing and imaging have been supplemented with discussions on materials for nanofiber formation, along with sensitizing materials, and formation of sensing elements by processes like surface deposition on nanofibers, immobilising, calcination, etc. and their effect on final sensing device properties. The review culminates by summarising the conceptual understanding of the hitherto progress leading to achievement of excellent analytical performance giving detection limits to the order of 1.6 pM concentration and response time of as low as 0.5 s. Current bottlenecks in this state of the art have been delineated and pathways for future research are discussed.

2D Hexagonal Boron Nitride-Coated Cotton Fabric with Self-Extinguishing Property.

Here, we report on the fabrication of flame retardant hydrophobic cotton fabrics based on the coating with two-dimensional hexagonal boron nitride (2D hBN) nanosheets. A simple one-step solution dipping process was used to coat the fabrics by taking advantage of the strong bonding between diethylenetriamine and hBN on the cotton surface. Exposure to direct flame confirmed the improvement of the flame retardant properties of the coated cotton fabrics. In turn, removal of the flame source revealed self-extinguishing properties. Molecular dynamics simulations indicate that hBN hinders combustion by reducing the rate at which oxygen molecules reach the cotton surface. This time-saving and one-step approach for the fabrication of flame-retardant cotton fabrics offers significant advantages over other, less efficient production methods.

A polydopamine-based platform for anti-cancer drug delivery.

Cancer is the second leading cause of death in the world with around 9.6 million deaths in 2018, approximately 70% of which occurred in the middle- and low-income countries; moreover, the economic impact of cancer is significant and escalating day by day. The total annual economic cost of cancer treatment in 2010 was estimated at approximately US$ 1.16 trillion. Researchers have explored cancer mitigation therapies such as chemo-thermal therapy, chemo-photothermal therapy and photodynamic-photothermal therapy. These combinational therapies facilitate better control on the tunability of the carrier for effectively diminishing cancer cells than individual therapies such as chemotherapy, photothermal therapy and targeted therapy. All these therapies come under novel drug delivery systems in which anti-cancer drugs attack the cancerous cells due to various stimuli (e.g. pH, thermal, UV, IR, acoustic and magnetic)-responsive properties of the anti-cancer drug carriers. Compared to conventional drug delivery systems, the novel drug delivery systems have several advantages such as targeted drug release, sustained and consistent blood levels within the therapeutic window, and decreased dosing frequency. Among the numerous polymeric carriers developed for drug delivery, polydopamine has been found to be more suitable as a carrier for these drug delivery functions due to its easy and cost-effective fabrication, excellent biocompatibility, multi-drug carrier capacity and stimuli sensitivity. Therefore, in this review, we have explored polydopamine-based carriers for anti-cancer drug delivery systems to mitigate cancer and simultaneously discussed basic synthesis routes for polydopamine.