CTAB enabled microwave-hydrothermal assisted mesoporous Zn-doped hydroxyapatite nanorods synthesis using bio-waste Nodipecten nodosus scallop for biomedical implant applications.

In biomedical exploration, the predominant characteristic is synthesizing and fabricating multifunctional nanostructure with intensified biocompatibility and excellent antibacterial applications to avoid post-surgical implant failure. The objective of the current study is to examine ideal mesoporous zinc-doped hydroxyapatite (HAp) for future use in the field of biomedical research. In the present investigation, we synthesized mesoporous Zn-doped HAp nanorods with varied mole concentrations using a profound microwave hydrothermal method utilizing bio-waste Nodipecten nodosus scallop as a calcium source and CTAB as an organic modifier. Bio-waste Nodipecten nodosus scallop is a widely available cheap calcium precursor which is converted into pure and zinc-doped hydroxyapatite nanorods with the help of the microwave hydrothermal method. Different analytical techniques like spectroscopy and electron microscopy were employed to evaluate and precisely characterize the structural and morphological characteristics in synthesized pure and mesoporous Zn-doped HAp nanorods. CTAB and microwave hydrothermal methods successfully create mesoporous Zn-doped hydroxyapatite nanorods with different sizes and morphology. Mesoporous Zinc-doped HAp nanorods show excellent antibacterial activity against Klebsiella pneumoniae (MTCC 7407) and Bacillus subtilis (MTCC 1133), compared to other nanorods. ZnHAp-3 shows notable excellent results of antibacterial effect towards K. pneumoniae and B. subtilis, by exhibiting 12.36 ± 0.12 and 13.12 ± 0.16 mm zone of inhibition. Furthermore, ZnHAp-1 shows the lower zone of inhibition, while the ZnHAp-3 sample shows the highest zone of inhibition. A foremost study performed was toxicity assays to validate safe attributes of mesoporous zinc-doped HAp intensified with the proliferation function of the zebrafish model. The results reveal the non-toxic behavior of pure and mesoporous zinc-doped HAp samples. Thus, our studies provide evidence for the synthesis technique for the mesoporous zinc-doped HAp nanorods using a novel CTAB-enabled microwave hydrothermal method utilizing bio-waste Nodipecten nodosus scallop as a calcium source will be alternative affordable biocidal antibacterial materials for controlling post-surgical implant failures.

Biomimetic facile synthesis of zinc oxide and copper oxide nanoparticles from Elaeagnus indica for enhanced photocatalytic activity.

The present study focused on synthesizing ZnO nanoparticles (NPs) and CuO NPs using Elaeagnus indica leaf extract as reducing and stabilizing agents using Zn(O2CCH3)2 and Cu2SO4, respectively, for the first time. We have confirmed the formation of aggregated ZnO NPs and CuO NPs with phytochemicals by various spectral analyses and electron microscopy studies. The size of synthesized ZnO NPs and CuO NPs were in the range of 20-30 nm and 30-40 nm, respectively. The antimicrobial activity of ZnO NPs at 75 µg concentration is superior against Salmonella typhimurium, Klebsiella pneumonia, Bacillus subtilis, Staphylococcus epidermidis, and Aspergillus niger. While CuO nanoparticles with 75 µg concentration effectively inhibited S. typhimurium, B. subtilis, S. epidermidis, and A. niger. Phytochemicals and reactive oxygen species generated by the prepared NPs may account for the antimicrobial effects observed. The photodegradation of methylene blue by ZnO NPs and CuO NPs was 91% and 76%, respectively, for 6 h of sunlight exposure. CuO NPs and ZnO NPs have different intrinsic properties and phytochemical compositions; hence ZnO NPs photodegrade faster than CuO NPs even though ZnO has higher bandgap energy than CuO. Consequently, CuO and ZnO NPs produced from E. indica leaf extract might be utilized as antimicrobials and photocatalysts in the future.

Citric Acid-Mediated Microwave-Hydrothermal Synthesis of Mesoporous F-Doped HAp Nanorods from Bio-Waste for Biocidal Implant Applications.

In this current research, mesoporous nano-hydroxyapatite (HAp) and F-doped hydroxyapatite (FHAp) were effectively obtained through a citric acid-enabled microwave hydrothermal approach. Citric acid was used as a chelating and modifying agent for tuning the structure and porosity of the HAp structure. This is the first report to use citric acid as a modifier for producing mesoporous nano HAp and F-doped FHAp. The obtained samples were characterized by different analyses. The XRD data revealed that F is incorporated well into the HAp crystal structure. The crystallinity of HAp samples was improved and the unit cell volume was lowered with fluorine incorporation. Transmission electron microscopy (TEM) images of the obtained samples revealed that a nano rod-like shape was obtained. The mesoporous structures of the produced HAp samples were confirmed by Brunauer-Emmett-Teller (BET) analysis. In vivo studies performed using zebrafish and C. elegans prove the non-toxic behavior of the synthesized F doped HAp samples. The obtained samples are also analyzed for antimicrobial activity using Gram-negative and Gram-positive bacteria, which are majorly involved in implant failure. The F doped samples revealed excellent bactericidal activity. Hence, this study confirms that the non-toxic and excellent antibacterial mesoporous F doped HAp can be a useful candidate for biocidal implant application.

Mesoporous Mn-doped hydroxyapatite nanorods obtained via pyridinium chloride enabled microwave-assisted synthesis by utilizing Donax variabilis seashells for implant applications.

Manganese-doped mesoporous hydroxyapatite (MnHAp) nanorods, a bio-apatite were synthesized via pyridinium chloride mediated microwave approach using bio-waste Donax variabilis seashells to treat orthopedic infections. This is the first report on using pyridinium chloride mediated mesoporous MnHAp nanorods synthesis. Pure and Mn doped HAp samples were examined using Raman spectroscopy, X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) studies to confirm the prepared HAp nanorods. Furthermore, the fabrication of manganese-doped HAp was successful with the formation of a hexagonal crystal lattice without disturbing the HAp phase. It is because, at the time of synthesis, PO43- ions form an electrostatic interaction with the Mn ions. Furthermore, Mn-doped HAp samples showed a reduction in their sizes of 15, 10-15, 5-10 nm width, and 80-100, 10-15, 20-30 nm length with varied pore diameters and surface area. The pure HAp, MnHAp-1, MnHAp-2, and MnHAp-3 nanorods disclose the surface area of 39.4, 18.0, 49.2, and 80.4 m2 g-1, with a pore volume of 0.0102, 0.0047, 0.0143, and 0.0447 cm3 g-1, the corresponding pore diameter was estimated to be 6, 7, 6, and 4 nm, respectively. Moreover, antibacterial activity reveals effective bactericidal action against infections causing pathogens whereas cytotoxicity examination (MTT assay), and zebrafish results reveal their non-toxic behavior. Therefore, it is evident from the study, that rapid fabrication of mesoporous and diverse structured MnHAp nanorods could be convenient with pyridinium chloride enabled microwave-assisted method as a bactericidal biomaterial for implant applications.

Ascorbic Acid-Assisted Microwave Synthesis of Mesoporous Ag-Doped Hydroxyapatite Nanorods from Biowaste Seashells for Implant Applications.

Post-surgery implant infection is one of the most challenging issues in orthopedics and it is mainly caused by infective micro-organisms. A potential approach to overcome this issue is developing biomaterials with efficient antibacterial activity. The main intention of this present research is devoted to ascorbic acid-assisted microwave synthesis of mesoporous (silver) Ag-doped hydroxyapatite (HAp) nanorods using biowaste seashells with antibacterial properties. XRD, FTIR, and Raman spectroscopy results revealed that the synthesized nanoparticles are hexagonal crystalline HAp. Further, the silver-doped HAp was also successfully produced without affecting the HAp crystalline phase by forming electrostatic interaction with PO43- ions during the synthesis. The morphological features confirm that the pure HAp is elongated mesoporous nanorods with 20 nm width and 300-500 nm length. However, silver doped HAp nanoparticles such as AgHA-1, AgHA-2, and AgHA-3 are found to be similar mesoporous rods but with different aspect ratios in sizes of 15, 10-15, and 5-10 nm width and 80-100, 10-15, and 20-30 nm length. The BET specific surface areas were obtained as 29 ± 3, 84 ± 2, 87 ± 2, and 128 ± 3 m2 g-1, and pore diameters were 4.68, 4.18, 9.30, and 3.77 nm, respectively, for pure HA, AgHA-1, AgHA-2, and AgHA-3. Therefore, HAp nanoparticles with different dimensions and mesoporous structures could be rapidly prepared using a microwave-assisted method and ascorbic acid as a supporting material. In addition, the synthesized HAp nanoparticles are analyzed for its antibacterial and cytotoxicity studies. The antibacterial and cytotoxicity study clearly reveals that the Ag-doped HAp nanorods are efficiently antibacterial and nontoxic in nature. Hence, it is clear that the ascorbic acid-enabled microwave-assisted method will be one of the best methods for the rapid production of HAp nanoparticles with different dimensions and mesoporous structures for its application as an implant material.