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Plants are anatomically and physiologically different from humans and animals; however, there are several possibilities to utilize the unique structures and physiological systems of plants and adapt them to new emerging technologies through a strategic biomimetic approach. Moreover, plants provide safe and sustainable results that can potentially solve the problem of mass-producing practical materials with hazardous and toxic side effects, particularly in the biomedical field, which requires high biocompatibility. In this review, it is investigated how micro-nanostructures available in plants (e.g., nanoparticles, nanofibers and their composites, nanoporous materials, and natural micromotors) are adapted and utilized in the design of suitable materials for a micro-nanorobot platform. How plants' work on micro- and nanoscale systems (e.g., surface roughness, osmotically induced movements such as nastic and tropic, and energy conversion and harvesting) that are unique to plants, can provide functionality on the platform and become further prospective resources are examined. Furthermore, implementation across organisms and fields, which is promising for future practical applications of the plant-actuated micro-nanorobot platform, especially on biomedical applications, is discussed. Finally, the challenges following its implementation in the micro-nanorobot platform are also presented to provide advanced adaptation in the future., (© 2022 Wiley-VCH GmbH.)

Biopolymers-induced immune microenvironment exhibited prominent effects on bone regeneration. Osteo-immunomodulatory responses of cellulose nanoparticles incorporated chitosan hydrogel scaffolds have not yet been reported. The objective of this study was to monitor the synergistic effects of silk fibroin and cellulose nanoparticles on the immune-modulatory behavior of chitosan biopolymer scaffolds. 3D-printed biodegradable cellulose nanoparticles-reinforced chitosan/silk fibroin (CS/SF/CNPs) scaffolds were fabricated and characterized by different spectroscopic techniques. The improved rheological and recovery strength was observed in CS/SF/CNPs hydrogels than pure polymer hydrogels. A significant shift from M1 → M2 macrophages polarization occurred in the CS/SF/CNPs scaffolds treated groups than the control after 3 days of incubation, showing its immune-modulatory potential. Osteo-immunomodulatory effects of the fabricated scaffolds were analyzed on human bone marrow-derived mesenchymal stem cells (hBMSCs), with macrophages-derived conditioned media (M-CM). Enhanced bone regeneration was observed in the calvaria defect rat model, indicating that the fabricated scaffolds are promising materials for bone-healing applications., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Chitosan-based hydrogels have received significant interest in tissue engineering and regenerative medicine applications owing to their superior biocompatibility. However, their applications are restricted owing to their weak mechanical strength. Cellulose nanocrystals (CNCs) are often explored as reinforcing agents to improve the native properties of polymers owing to their superior physicochemical properties. We fabricated a multi-functional hydrogel scaffold of chitosan/CNCs by incorporating different amounts of CNCs into a chitosan (CH) hydrogel. Significant enhancement in the mechanical strength was noted in the CH/CNCs as compared to that in pure CH hydrogel scaffolds. The cytocompatibility of the fabricated scaffolds was monitored in the presence of bone-marrow-derived mesenchymal stem cells (BMSCs). Improved cell viability and mineralization were observed with CH/CNC hydrogel scaffolds than those with pure CH hydrogel scaffolds. Enhanced osteogenic-related gene expression was observed in the CH/CNC hydrogel scaffold environment than that in the control, indicating their osteogenic potential, in addition to enhanced antibacterial activity. Developed composite scaffolds exhibited improved sustained drug release compared to that by pure polymer scaffolds, and this was more sustained in the scaffolds with higher CNC content. Therefore, the fabricated scaffolds may have been used in tissue engineering for osteogenesis, as antibacterial agents, and in sustained drug delivery., Competing Interests: Declaration of competing interest None., (Copyright © 2020. Published by Elsevier B.V.)

Cellulose nanocrystals (CNCs) have received a significant amount of attention from the researchers. It is used as a nanomaterial for various applications due to its excellent physiochemical properties for the last few decades. Self-assembly is a phenomenon where autonomous reorganization of randomly oriented species occurs elegantly. Self-assembly is responsible for the formation of the hierarchical cholesteric structure of CNCs. This process is highly influenced by several factors, such as the surface chemistry of the nanoparticles, intermolecular forces, and the fundamental laws of thermodynamics. Various conventional experimental designs and molecular dynamics (MD) studies have been applied to determine the possible mechanism of self-assembly in CNCs. Different external factors, like pH, temperature, magnetic/electric fields, vacuum, also influence the self-assembly process in CNCs. Notably, better responses have been observed in CNCs-grafted polymer nanocomposites. These functionalized CNCs with stimuli-responsive self-assembly have immense practical applications in modern biotechnology and medicine. Herein, we have concisely discussed the mechanism of the self-assembled CNCs in the presence of different external factors such as pH, temperature, electric/magnetic fields, and their biomedical applications., Competing Interests: Declaration of competing interest The authors declare no competing financial interests., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Nanocrystalline hydroxyapatite (HAp) was synthesized from biowaste eggshells through sonication followed by the heat treatment. Calcium oxide as a precursor moiety for the synthesis of HAp was obtained through the heat treatment of eggshells at 900°C for 3 hr. The prepared HAp was characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). The appearance of the FTIR absorption peaks in between at 516-1031 and 3,636 cm -1 shows phosphate and hydroxyl groups in prepared HAp, respectively. The XRD-patterns indicate the formation of HAp started within 5 min of sonication. The SEM morphologies suggested that the synthesized HAp was highly crystalline and compact. We tested the elemental analysis of the synthesized HAp through X-ray fluorescence spectroscopy and inductively coupled plasma mass spectroscopy. The higher Ca/P ratio has observed in heat-treated HAp. These results show that heat treatment facilitates the formation of highly crystalline and compact HAp. Cytotoxicity and osteogenic potential of human mesenchymal stem cells (hMSCs) were also evaluated in the presence of HAp. No significant cytotoxicity was noted in the presence of HAp, suggested their biocompatibility. Enhanced osteogenesis of hMSCs occurred with HAp powder, confirming the feasibility in the treatment of osteogenesis. Thus, synthesized HAp has the potential to use a biomaterial in tissue engineering applications for bone tissues., (© 2019 Wiley Periodicals, Inc.)

A facile supramolecular approach to prepare surface functionalized silver nanoparticle conjugates has been established and their enhanced molecular recognition features have been explored to demonstrate the uptake and stimulus responsive release of a phototherapeutic porphyrin dye, the TMPyP.