Browsing by Author "Chandkiram Gautam"

Now showing 1 - 18 of 18

3D nanocomposites of β-TCP-H3BO3-Cu with improved mechanical and biological performances for bone regeneration applications
(Nature Research, 2025) Sarvesh Kumar Avinashi; Rajat Kumar Mishra; n. Shweta; Saurabh Kumar; Amreen Shamsad; Shama Parveen; Surajita Sahu; Savita Kumari; Zaireen Fatima; Sachin Kumar Yadav; Monisha Banerjee; Monalisa Mishra; Neeraj Mehta; Chandkiram Gautam
Recently, 3-D porous architecture of the composites play a key role in cell proliferation, bone regeneration, and anticancer activities. The osteoinductive and osteoconductive properties of β-TCP allow for the complete repair of numerous bone defects. Herein, β-TCP was synthesized by wet chemical precipitation route, and their 3-D porous composites with H3BO3 and Cu nanoparticles were prepared by the solid-state reaction method with improved mechanical and biological performances. Several characterization techniques have been used to investigate the various characteristics of fabricated porous composites. SEM and TEM studies revealed the porous morphology and hexagonal sheets of the β-TCP for the composite THC8 (82TCP-10H3BO3-8Cu). Moreover, the mechanical study showed excellent compressive strength (188 MPa), a high Young’s modulus (2.84 GPa), and elevated fracture toughness (9.11 MPa.m1/2). An in vitro study by MTT assay on osteoblast (MG-63) cells demonstrated no or minimal cytotoxicity at the higher concentration, 100 µg/ml after 24 h and it was found a more pronounced result at 20 µg/ml on increasing the concentration of Cu nanoparticles after incubating 72 h. The THC12 composite showed the highest antibacterial potency exclusively against B. subtilis. S. pyogene, S. typhi and E. coli. at 10 mg/ml, indicating its potential effectiveness in inhibiting all of these pathogens. Genotoxicity and cytotoxicity tests were also performed on rearing Drosophila melanogaster, and these findings did not detect any trypan blue-positive staining, which further recommended that the existence of composites did not harm the larval gut. Therefore, the fabricated porous composites THC8 and THC12 are suitable for bone regrowth without harming the surrounding cells and protect against bacterial infections. © The Author(s) 2025.
A novel nanocomposite of HAp-TiC-Ag with enhanced mechanical and biological properties for bone regrowth and anticancer applications
(Royal Society of Chemistry, 2025) Sarvesh Kumar Avinashi; Shweta; Rajat Kumar Mishra; Saurabh Kumar; Amreen Shamsad; Shama Parveen; Surajita Sahu; Savita Kumari; Zaireen Fatima; Vijay Pratap; Rupesh Kumar; Monisha Banerjee; Monalisa Mishra; Horesh Kumar; Rakesh Kumar C. Gautam; Chandkiram Gautam
Hydroxyapatite (HAp)-based composites are extensively used in various applications, including bone regeneration, bone implants, catalysis, drug delivery, and cancer treatment, owing to their unique properties such as osteogenesis, osteoconduction, and osteoinduction, as well as their ability to inhibit tumor cell growth. In this study, pure HAp and silver (Ag) nanoparticles were synthesized using microwave irradiation and green synthesis methods, while a solid-state reaction route was employed for the fabrication of HAp-TiC-Ag composites aimed at enhancing their mechanical and biological properties. A range of characterization techniques, including XRD, FTIR, Raman, XPS, DLS, SEM, TEM, and in vitro assays, were used to assess the structural, morphological, mechanical, and biological properties of the composites. The composite HTA6 exhibited excellent mechanical properties, including a high compressive strength (185 MPa), elevated fracture toughness (10.88 MPa m1/2), a moderate Young's modulus (1.08 GPa), and a Vickers hardness (339.65 HV). The cell viability tests demonstrated that HTA6 treatment did not significantly reduce osteoblast cell growth, while significantly inhibiting the proliferation of cancer cells. Additionally, the composite showed good biocompatibility, displaying non-cytotoxicity in D. melanogaster and strong antibacterial activities against the tested bacteria. These findings suggest that HTA6 is a promising candidate for applications in bone regeneration and cancer treatment. © 2025 The Royal Society of Chemistry.
Doping impacts of La2O3 on physical, structural, optical and radiation shielding properties of (30-x)BaCO3-30TiO2-40SiO2-xLa2O3 (0 ≤ x ≤ 6) glasses for optoelectronic applications
(Institute of Physics, 2023) Rajat Kumar Mishra; Savita Kumari; Shweta; Prince Sen; Sarvesh Kumar Avinashi; Zaireen Fatima; Harel Thomas; Manasi Ghosh; Krishna Kishor Dey; Chandkiram Gautam
Herein, synthesis of novel barium silicate glasses doped with La2O3 in the system (30-x)BaCO3-30TiO2-40SiO2-xLa2O3, BTSL (0 ≤ x ≤ 6) via fast melt-quenching technique was carried out. Further, to confirm the amorphous behaviour of prepared glass samples, x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were carried out. The density of all prepared glasses was determined using Archimedes’ principle and found to be in an increasing manner. To investigate the doping influence of La2O3 on the glasses, few more physical properties like molar volume (Vm), polaron radius (rp), and field strength (Fs) were also studied and found to be increased due to incorporation of La2O3 into BTSL glassy system. Moreover, to explore the structural, functional, and bonding mechanism of the glasses, FTIR, Raman and 29Si-MAS-ssNMR spectroscopies were performed. Further, to investigate the numerous optical parameters, UV-visible spectroscopy was executed, and energy band gaps were found in the decreasing manner as increasing the La2O3 concentrations. Additionally, to study the optoelectronic properties, refractive indices (η) and optical dielectric constant (ϵ) were determined and revealed the increasing behaviour and found suitable material for optoelectronic devices. Furthermore, the radiation shielding parameters, mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), etc were determined using Phy-X/PSD software and these parameters are increased owing to the doping of La2O3. Among all fabricated glasses, (30-x)BaCO3-30TiO2−40SiO2−6La2O3, BTS6L glass exhibited outstanding optical and radiation attenuation properties; can be tailored for the fabrication of optoelectronic and radiation protection devices. © 2023 IOP Publishing Ltd.
Enhanced mechanical properties and hydrophilic behavior of magnesium oxide added hydroxyapatite nanocomposite: A bone substitute material for load bearing applications
(Elsevier Ltd, 2020) Sunil Kumar; Chandkiram Gautam; Brijesh Singh Chauhan; Saripella Srikrishna; Ram Sagar Yadav; Shyam Bahadur Rai
Hydroxyapatite is a multifunctional biomaterial that combines biocompatibility and bioactivity for various biomedical applications such as bone repairing and bioimaging. In the present study nano-hydroxyapatite (n-HAp) was synthesized using microwave irradiation technique. Subsequently, the MgO was introduced into the n-HAp matrix and various bioactive compositions of HAp-MgO nanocomposites were fabricated. The structural, mechanical, in vivo cell viability, and in vivo imaging properties of these nanocomposites were studied. The XRD results show that the composites sintered at 1200 °C, n-HAp partially decomposed into beta-tricalcium phosphate (β-TCP). The sintered density of the composites varying from 2.72 ± 0.066 to 3.03 ± 0.093 g cm−3 with the addition of 0.0–2.0 wt % of MgO. As increasing the amounts of MgO, a remarkable increase in the mechanical properties of the composite was achieved. The composite HAp-1.0MgO exhibited the highest mechanical properties with a compressive strength of 111.20 ± 5 MPa, fracture toughness 136.98 ± 5 MJ/m3 and revealed much amplification than pure n-HAp. Thus, the addition of MgO acting as an excellent mechanical reinforcing agent. The surface morphology of the composites revealed a significant change in the porous surface to denser. The low contact angle revealed the considerable hydrophilic nature of the composite surface. The biological study of these nano-composites with Drosophila third instar larvae indicated comparable or more favorable biocompatibility in terms of cell viability. Also internalized by Drosophila third instar larvae exhibited fluorescence under green and red filters using epifluorescence microscopy. Thus, the fabricated HAp-MgO nanocomposites with excellent biological properties are expected to be a multifunctional bioactive material for bone tissue regeneration and cell imaging applications. © 2020 Elsevier Ltd and Techna Group S.r.l.
Enhanced mechanical properties of hBN-ZrO2 composites and their biological activities on: Drosophila melanogaster: Synthesis and characterization
(Royal Society of Chemistry, 2019) Amarendra Gautam; Chandkiram Gautam; Monalisa Mishra; Vijay Kumar Mishra; Ajaz Hussain; Swetapadma Sahu; Reetuparna Nanda; Bikash Kisan; Santoshkumar Biradar; Rakesh Kumar Gautam
In this study, six compositions in the system [x(h-BN)-(100 - x)ZrO2] (10 ≤ x ≤ 90) were synthesized by a bottom up approach, i.e., the solid-state reaction technique. XRD results showed the formation of a novel and main phase of zirconium oxynitrate ZrO(NO3)2 and SEM exhibited mixed morphology of layered and stacked h-BN nanosheets with ZrO2 grains. The composite sample 10 wt% h-BN + 90 wt% ZrO2 (10B90Z) showed outstanding mechanical properties for different parameters, i.e., density (3.12 g cm-3), Young's modulus (10.10 GPa), toughness (2.56 MJ m-3), and maximum mechanical strength (227.33 MPa). The current study further checked the in vivo toxicity of composite 10B90Z and composite 90B10Z using Drosophila melanogaster. The composite 10B90Z showed less cytotoxicity in this model, while the composite 90B10Z showed higher toxicity in terms of organ development as well as internal damage of the gut mostly at the lower concentrations of 1, 10, and 25 μg mL-1. Altogether, the current study proposes the composite 10B90Z as an ideal compound for applications in biomedical research. This composite 10B90Z displays remarkable mechanical and biological performances, due to which we recommend this composition for various biomedical applications. © ??? The Royal Society of Chemistry.
Enhanced physical and mechanical properties of resin added with aluminum oxyhydroxide for dental applications
(Elsevier Ltd, 2023) Savita Kumari; Ajaz Hussain; Sarvesh Kumar Avinashi; Rajat Kumar Mishra; Jitendra Rao; Sudhakar Behera; Rakesh Kumar Gautam; Chandkiram Gautam
Resin has limited applications however, its composites with metal oxides exhibited improved characteristics for numerous applications such as dental restoration, dentures etc. Herein, various compositions were fabricated by substituted aluminum oxyhydroxide (AlOOH) into resin via a scalable heat cure process. For phase identification and structural study, XRD and FT-IR techniques were employed. As increasing the content of AlOOH into the PZ {Poly (methyl-methacrylate)-zirconia, (PMMA-ZrO2)} matrix, the percentage of crystallinity and the crystallite size were also estimated and varied from 14.8 to 18.4 and 1.48 nm–1.82 nm respectively. Moreover, to reveal the surface morphology, optical and mechanical behaviour of fabricated nano-composites, the SEM, UV–Vis and Universal testing machine (UTM) were also performed. The direct, indirect band gap, urbach energy of the fabricated composites were noticed within the range of 5.14 ± 0.005–5.19 ± 0.005 eV, 5.31 ± 0.005–5.35 ± 0.005 eV, and 189 ± 3.78–69.6 ± 1.39 eV respectively. The skin depth of the nanocomposites were also studied, the cut-off energy and cutoff-wavelength are 5.66 eV and 220 nm. However, the compressive strength, flexural strength, and the lowest friction coefficient value at 1 m/s sliding speed of the best composite sample (PZA15) are 85.2 MPa, 56.7 MPa and 0.311. The highest flexural modulus (846 MPa) of the PZA15 were determined using the 3-point bending test. Further, to check the biocompatibility of these resin-based composites the MTT assay was carried out. The synthesized composite (PZA15) was found to be highly biocompatible with enhanced mechanical and tribological performances. © 2023 Elsevier Ltd and Techna Group S.r.l.
Fabrication of bioactive transparent glass ceramics 55SiO2–25Na2O-(15-x)CaO–5P2O5- xZrO2 (0≤x≤6): Physical, structural and in vitro cell viability insights for biomedical applications
(Elsevier Ltd, 2024) Shweta; Rajat Kumar Mishra; Bijay Laxmi Pradhan; Shama Parveen; Priyatama Behera; Sarvesh Kumar Avinashi; Savita Kumari; Zaireen Fatima; Prince Sen; Saurabh Kumar; Monalisa Mishra; Monisha Banerjee; Krishna Kishor Dey; Manasi Ghosh; Chandkiram Gautam
Zirconia (ZrO2) reinforced transparent glass ceramics (TGCs) are excellent materials for enhanced cell viability and biocompatibility for biomedical applications. Herein, ZrO2 doped SiO2–Na2O–CaO–P2O5 base compositions derived from traditional melt-quench technique. The impacts of ZrO2 on the physical, structural, optical, morphological, and biological evaluation were studied. XRD discloses the major phase formation of buchwaldite (CaNaPO4) and disodium calcium silicate (Na2CaSiO4). Density of the TGC samples was calculated and found to be in the range of 2.535–2.910 g/cm3. The optical parameters, and particle size were estimated and analyzed. Herein, ZrO2 plays a significant role as a network modifier and various bond assignments in the glassy network that confirmed by FTIR spectroscopy. Surface morphology and its elemental investigations were also studied using SEM and XPS techniques. Solid state NMR spectrum on 23Na, 29Si, and 31P nucleus were studied for various interactions. Moreover, the cell viability of the fabricated samples on the cancer cells were analyzed and resulted to possess the half maximum inhibitory concentrations (IC50) of the samples were calculated and valued to be 92 to 40 μg/ml respectively. The sample 55SiO2–25Na2O–9CaO–5P2O5–6ZrO2 (BG4) demonstrated a remarkable biological activity for bone regeneration and implants. Further, the cell cytotoxicity was evaluated by performing trypan blue assay, DAPI and DCFH-DA staining on the TGC samples. The data assembled in this research approves the hypothesis that the TGCs represent a feasible material for the biomedical applications for bone and tooth implants. © 2024 Elsevier Ltd and Techna Group S.r.l.
Fabrication of Graphene Nanoplatelet-Incorporated Porous Hydroxyapatite Composites: Improved Mechanical and in Vivo Imaging Performances for Emerging Biomedical Applications
(American Chemical Society, 2019) Sunil Kumar; Chandkiram Gautam; Vijay Kumar Mishra; Brijesh Singh Chauhan; Saripella Srikrishna; Ram Sagar Yadav; Ritu Trivedi; Shyam Bahadur Rai
Three-dimensional nanocomposites exhibit unexpected mechanical and biological properties that are produced from two-dimensional graphene nanoplatelets and oxide materials. In the present study, various composites of microwave-synthesized nanohydroxyapatite (nHAp) and graphene nanoparticles (GNPs), (100 - x)HAp-xGNPs (x = 0, 0.1, 0.2, 0.3, and 0.5 wt %), were successfully synthesized using a scalable bottom-up approach, that is, a solid-state reaction method. The structural, morphological and mechanical properties were studied using various characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and universal testing machine (UTM). XRD studies revealed that the prepared composites have high-order crystallinity. Addition of GNPs into nHAp significantly improved the mechanical properties. Three-dimensional nanocomposite 99.5HAp-0.5GNPs exhibited exceptionally high mechanical properties, for example, a fracture toughness of ∼116 MJ/m3, Young's modulus of ∼98 GPa, and compressive strength of 96.04 MPa, which were noticed to be much greater than in the pure nHAp. The MTT assay and cell imaging behaviors were carried out on the gut tissues of Drosophila third instars larvae and on primary rat osteoblast cells for the sample 99.5HAp-0.5GNPs that have achieved the highest mechanical properties. The treatment with lower concentrations of 10 μg/mL on the gut tissues of Drosophila and 1 and 5 μg/mL of this composite sample showed favorable cell viability. Therefore, owing to the excellent porous nature, interconnected surface morphology, and mechanical and biological properties, the prepared composite sample 99.5HAp-0.5GNPs stood as a promising biomaterial for bone implant applications. © 2019 American Chemical Society.
Fabrication, structural, and enhanced mechanical behavior of MgO substituted PMMA composites for dental applications
(Nature Research, 2024) Savita Kumari; Rajat Kumar Mishra; Shama Parveen; Sarvesh Kumar Avinashi; Ajaz Hussain; Saurabh Kumar; Monisha Banerjee; Jitendra Rao; Rupesh Kumar; Rakesh Kumar Gautam; Chandkiram Gautam
The most common denture material used for dentistry is poly-methyl-methacrylate (PMMA). Usually, the polymeric PMMA material has numerous biological, mechanical and cost-effective shortcomings. Hence, to resolve such types of drawbacks, attempts have been made to investigate fillers of the PMMA like alumina (Al2O3), silica (SiO2), zirconia (ZrO2) etc. For the enhancement of the PMMA properties a suitable additive is required for its orthopedic applications. Herein, the main motive of this study was to synthesize a magnesium oxide (MgO) reinforced polymer-based hybrid nano-composites by using heat cure method with superior optical, biological and mechanical characteristics. For the structural and vibrational studies of the composites, XRD and FT-IR were carried out. Herein, the percentage of crystallinity for all the fabricated composites were also calculated and found to be 14.79–30.31. Various physical and optical parameters such as density, band gap, Urbach energy, cutoff energy, cutoff wavelength, steepness parameter, electron–phonon interaction, refractive index, and optical dielectric constant were also studied and their values are found to be in the range of 1.21–1.394 g/cm3, 5.44–5.48 eV, 0.167–0.027 eV, 5.68 eV, 218 nm, 0.156–0.962, 4.273–0.693, 1.937–1.932, and 3.752–3.731 respectively. To evaluate the mechanical properties like compressive strength, flexural strength, and fracture toughness of the composites a Universal Testing Machine (UTM) was used and their values were 60.3 and 101 MPa, 78 and 40.3 MPa, 5.85 and 9.8 MPa-m1/2 respectively. Tribological tests of the composites were also carried out. In order to check the toxicity, MTT assay was also carried out for the PM0 and PM15 [(x)MgO + (100 − x) (C5O2H8)n] (x = 0 and 15) composites. This study provides a comprehensive insight into the structural, physical, optical, and biological features of the fabricated PMMA-MgO composites, highlighting the potential of the PM15 composite with its enhanced density, mechanical strength, and excellent biocompatibility for denture applications. © 2024, The Author(s).
Formation of multifunctional ZrO2–MgO-hBN nanocomposite for enhanced bone regeneration and E coli bacteria filtration applications
(Elsevier Ltd, 2020) Ajaz Hussain; Chandkiram Gautam; Asif Jafri; Vijay Kumar Mishra; Abhishek Madheshiya; Amarendra Gautam; Manvandra Kumar Singh; Rakesh Kumar Gautam; Manisha Gupta; Md Arshad; Robert Vajtai; Pulickel M. Ajayan
Due to adequate properties, bone implant materials have attracted much attention to repair the large-sized bone fractures which cannot be auto-healed. Recently, three-dimensional (3-D) nanocomposites were synthesized using two-dimensional (2-D) materials which reveals unexpected performances. In the present study, 3-D mesoporous biocomposites were developed for bone/dental implant applications. A ternary novel biocomposite system ZrO2–MgO-hBN was fabricated with low density, high strength, and mesoporous interconnected architecture using conventional bottom-up synthesis method. Due to remarkable stability in different fluids such as water, minimum essential medium eagle-alpha modification (α-MEM), acids and oils, the fabricated biocomposites displayed multifunctional activities along with suitable proliferation of osteoblast like MG63 cell and filtration of Escherichia coli (E-coli) bacteria from the water. Moreover, the biocomposite exhibited protective nature from harmful ultraviolet (UV) radiation. A new phase of hexagonal boron nitride (h-BN) in the form of highly porous nanotubes was observed that opens the new possibility to optimize the synthesis of porous h-BN nanotubes to explore their further applications. Therefore, based on mechanical, tribological and biological performances, the nanocomposite is a biomimetic material having potential as bone/dental implant and can be used for multifunctional applications. © 2020 Elsevier Ltd and Techna Group S.r.l.
Influence of carbon nanotubes reinforcement on the structural feature and bioactivity of SiO2–Al2O3–MgO–K2CO3–CaO–MgF2 bioglass
(Springer Science and Business Media Deutschland GmbH, 2021) Shweta; Chandkiram Gautam; Krishna Kishor Dey; Manasi Ghosh; Ravi Prakash; Kriti Sharma; Divya Singh
Various glass compositions were synthesized using a melt-quenching technique doped with different concentrations of carbon nanotubes (CNTs) from 0.1 to 0.7% in the glassy system SiO2–Al2O3–MgO–K2CO3–CaO–MgF2. Density was determined by employing a liquid displacement method. Several physical parameters such as molar volume (Vm), oxygen molar volume (Vo) were calculated and found to be decreases from 36.49 ± 0.729 to 24.28 ± 0.485 × 10–6 m3/mol, and 21.86 ± 0.437 to 14.60 ± 0.292 × 10–6 m3/mol, respectively. However, density and oxygen packing density (OPD) increases from 1.99 ± 0.099 to 2.98 ± 0.149 × 103 kg/m3 and 45.74 ± 0.914 to 68.49 ± 1.369 × 10–3 kg-atom/l with increasing content of CNT. In the present study, reinforcement effects of CNTs were explained using several spectroscopic techniques like Fourier transform infrared, ultraviolet–visible (UV–Vis), Raman, and nuclear magnetic resonance (NMR) spectroscopy, respectively. Based on Tauc plots of the UV–Vis spectra, the energy band gap was determined and their values decreased from 6.95 to 6.23 × 10–19 J which is owing to the formation of non-bridging oxygen (NBO) in the glassy matrix. Contact angle measurements were also performed to check the wettability of the glasses and their values increased with CNT % from 18.14° to 77.8°. 29Si-MAS-NMR spectroscopic study revealed the random distribution of two different cations, Ca 2 + and Mg 2 + within the glasses which lead to structural and topological frustration. To check the cell viability, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and alkaline phosphatase assay were also performed. Owing to outstanding stability in various fluids like saline water, distilled water, and hydrochloric acid, the fabricated glasses exhibited functional activities with an adequate proliferation of rat calverail osteoblast cells. Consequently, based on the various characterization techniques such as mechanical, tribological, and biological activities, the fabricated bioactive glasses can be used for biomedical and multifunctional applications. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.
Influence of TiO2as a filler into PMMA-ZrO2composites on structural, mechanical and biological properties for denture fabrication
(Elsevier Ltd, 2025) Akhileshwar Gupta; Savita Kumari; Sarvesh Kumar Avinashi; Rajat Kumar Mishra; Rupesh Kumar; Priyatama Behera; Monalisa Mishra; Rakesh Kumar C. Gautam; Saurabh Kumar; Shama Parveen; Jitendra Rao; Monisha Banerjee; Chandkiram Gautam
Polymethyl-methacrylate (PMMA) is widely being used in dentistry, while it has limited mechanical strength. Herein, PMMA composites were fabricated using heat cure technique within a system [(95-x) PMMA + 5 ZrO2 + x TiO2] (x = 8, 6, 4 and 2 wt%) and thoroughly characterized using density measurements, XRD, FTIR, SEM, EDAX, compression tests, 3-point bending, tribological, and hardness tests respectively. Moreover density, crystallite size, percentage of crystallinity, compressive strength, Young's modulus, flexural strength, flexural modulus, modulus of resilience, modulus of toughness, and brittleness coefficient were determined. Composite contains 5 wt% ZrO2and 2 wt% TiO2referred as ZPT2 exhibited the maximum compressive strength. Additionally, flexural strength and flexural modulus were found to be highest for ZPT2. The friction coefficient and hardness were found to be the lowest for ZPT2. In MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5- diphenyl tetrazolium bromide) assay, MG-63 osteoblast cells were exposed to various concentrations (5–30 μg/ml) of the compounds for 24 h. The results indicated that no significant cytotoxicity was observed for ZPT2. According to the results of the dye exclusion experiment, DAPI (4, 6-diamidino-2-phenylindole), and DCFH-DA (2, 7-dichlorodihydrofluorescein diacetate) staining, ZPT2 did not exhibit cellular damage, genotoxicity and reduced ROS (reactive oxygen species) production at lower concentrations. The combined biological results suggest that oral administration of the ZPT2 sample does not exhibit cytotoxicity and genotoxicity that makes it valuable for dentistry. © 2025 Elsevier Ltd and Techna Group S.r.l. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Physical, Structural, and Optical Properties of ZrO2 Reinforced (100-x–y)[SrTiO3]-x[2B2O3.SiO2]-y[ZrO2] Glasses
(Springer Science and Business Media B.V., 2023) Rajat Kumar Mishra; Shweta; Prince Sen; Krishna Kishor Dey; Manasi Ghosh; Chandkiram Gautam
Several attempts were made to fabricate zirconia (ZrO2) reinforced strontium titanate (SrTiO3) borosilicate glasses in the system (100-x–y)[SrTiO3]-x[2B2O3.SiO2]-y[ZrO2] (38 ≤ x ≤ 39, 0 ≤ y ≤ 4 by mole %) via a rapid melt-quenching method. To check the amorphous behaviour of the prepared glasses, XRD measurements were performed. Further, density of the bulk transparent glasses was evaluated by liquid-displacement method (Archimedes’ principle) and found to be in the range of 2.6068–3.0720 gcm−3. To study the effect of ZrO2 doping on the fabricated glasses, various physical parameters such as oxygen molar volume (Omv), molar volume (Vm), oxygen packing density (OPD), ion-concentrations (N), etc. were determined. Further, to investigate the molecular structure, and bonding information, FTIR spectroscopy was performed. Additionally, to determine the various optical properties, the UV–visible spectroscopy was also performed, and with the help of Davis-Mott plots, increasing optical band gap energies were obtained in the range of 4.29—4.78 eV. Besides these parameters, an optical dielectric constant (ε), and average refractive index (η) were determined which lies within the increasing range of 120.0374–207.3341 and 1.9269–2.0690 respectively. Moreover, to elaborate the structure of the fabricated glasses, 29Si and 11B MAS SSNMR spectra were recorded which shows the formation of silicate networks which became highly polymerized with increasing concentrations of ZrO2. © 2023, The Author(s), under exclusive licence to Springer Nature B.V.
Preparation of ZrO2–ZnO-Poly-Methyl-Methacrylate Composite with Enhanced Physical and Mechanical Properties for Dentistry
(Springer, 2025) Akhileshwar Gupta; Rashmi Rekha Devi; Savita Kumari; Anshu Raj; Priyatama Behera; Monalisa Mishra; Rakesh Kumar C. Gautam; Shama Parveen; Saurabh Kumar; Jitendra Rao; Monisha Banerjee; Chandkiram Gautam
Poly-methyl-methacrylate (PMMA) is the most widely used denture material for various dental applications. There are certain limitations associated with PMMA, such as its mechanical strength, dimensional stability and biocompatibility. In this study, efforts have been made to overcome these shortcomings by using ZrO2 and ZnO as fillers. The main motive of the study is to fabricate ZrO2 and ZnO reinforced PMMA composites with superior physical and mechanical properties. Herein, numerous composites were synthesized within a system [(95−x) PMMA + 5 ZrO2 + x ZnO)] (x = 2, 4, 6 & 8% wt.) using a conventional heat cure method. A comprehensive evaluation of the PMMA-ZrO2–ZnO (PZZ) composites was carried out through both theoretical and experimental density measurements, along with a range of characterization techniques including XRD, SEM, compression and three-point bending tests, water sorption analysis, tribological testing, hardness assessment, and biological assays such as MTT, DAPI, DCFH-DA, and trypan blue staining. As the ZnO content increased, there was a corresponding rise in the density, crystallinity percentage, Young’s modulus, and flexural modulus of the composites. However, an increase in ZnO content led to a reduction in compressive strength, fracture toughness, and flexural strength of the PZZ composites. Biological evaluation indicated that cell viability was highest in composites with lower ZnO concentrations. Overall, this study provides comprehensive insights into the physical, mechanical, and biological properties of the synthesized PMMA-ZrO2–ZnO composites. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.
Synergetic impact of MgO on PMMA-ZrO2 hybrid composites: Evaluation of structural, morphological and improved mechanical behavior for dental applications
(Elsevier Inc., 2024) Savita Kumari; Anuj Verma; Rajat Kumar Mishra; Sarvesh Kumar Avinashi; Shweta; Shweta Singh; Priyatama Behera; Jitendra Rao; Rakesh Kumar Gautam; Bijay Laxmi Pradhan; Krishna Kishor Dey; Manasi Ghosh; Monalisa Mishra; Chandkiram Gautam
This work aims to demonstrate the effect of ZrO2 and MgO inclusion into the Poly(methyl methacrylate) (PMMA). To fabricate novel hybrid composites via heat cure method, various composites (PZM2, PZM4 and PZM6) were synthesized in the system [(95-x) PMMA + 5 ZrO2 + x MgO] (x = 2, 4, and 6) respectively. Density of the prepared composites were determined and varying between 1.035–1.152 g/cm3. X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) followed by EDAX and mechanical testing were performed to evaluate the fabricated composite properties. Moreover, to explore the structure of the fabricated composites the 13 C CP-MAS SSNMR and 1 H-13 C Phase-Modulated Lee Goldberg (PMLG) HETCOR Spectrum were recorded which clarify chemical shifting and motional dynamics of the composites. Mechanical tests were performed by UTM and the obtained parameters such as compressive strength, Young's modulus, fracture toughness, brittleness coefficient, flexural strength and flexural modulus are found to be in the range of 91–100 MPa, 0.48–0.51 GPa, 9.122–9.705 MPa.m1/2, 0.66–0.815, 51.03–42.78 MPa and 499–663 MPa respectively. Some more mechanical parameters such as proportional limit, elastic limit, failure strength, modulus of resilience and modulus of toughness were also calculated. Furthermore, tribological properties were also determined and the coefficient of friction (COF) was decreased by 17.4 % and 38 % for composite PZM6 at 20 N and 40 N as compared to the composite PZM2 and the lowest wear volume of 1.55 mm3 was observed for PZM2, whereas the maximum volume loss of 5.64 mm3 is observed for composite PZM6. To check out the biocompatibility, cytotoxicity and genotoxicity of the fabricated composites the Trypan-blue assay was also performed for PZM2 and PZM6 composites. Dissection on the gut of larvae was also performed on the both composites followed by DAPI and DCFH-DA staining. Therefore, these synthesized samples can be used for the fabrication of denture materials. © 2024 Elsevier Inc.
Synergistic doping effect of La2O3 on BaO-TiO2-SiO2 glass-ceramics: Evolution of physical, structural, morphological, and dielectric behaviour for electronics applications
(Elsevier Ltd, 2024) Rajat Kumar Mishra; Sarvesh Kumar Avinashi; Savita Kumari; Shweta; Rajbala Nain; Tarun Katheriya; Rakesh Kumar Dwivedi; Shail Upadhyay; Chandkiram Gautam
Herein, numerous investigations such as structural, physical, morphological, optical, and dielectric properties of BaO-TiO2-SiO2 glass-ceramics (GCs) doped with La2O3 were carried out. Various glasses were synthesized within a glass system [(30-x)BaO.30TiO2.40SiO2].x[La2O3], (x=0,2,4, and 6 mol% of La2O3) using a conventional melt-quench method. XRD confirmed the amorphous nature of the glass samples. Differential scanning calorimetry (DSC) was used to identify the glass transition (Tg) and crystallization temperatures (Tc) of the samples. Further, controlled heat treatment of the glasses led to the fabrication of glass-ceramics and their XRD analysis revealed polycrystalline structure, predominantly consisting of a major phase of tetragonal Fresnoite (Ba2TiO8Si2). Furthermore, with the addition of La2O3, the prepared GCs exhibited improved physical properties, including an increase in density (3.783–4.611 g/cm3) and oxygen packing density (81.177–92.303 g-atom/l). Additionally, to study the bonding and structural characteristics, FTIR and Raman spectroscopies were conducted. In order to study the optical properties, UV–visible spectroscopy was executed and showed a reduced indirect energy band gap from 4.290 to 4.220 eV with increasing La2O3. To study the morphological behaviour, SEM and TEM were performed. Eventually, to examine the dielectric characteristics, relative dielectric constant (εr) and dielectric loss (Tan δ) over the glass-ceramics was conducted using a ‘Novocontrol Impedance Analyzer’. The εr and Tan δ values exhibited temperature-dependent behaviour and found to be increased within the frequency range of 1 kHz to 1 MHz. The BTSLC6 glass-ceramic, (24BaO.30TiO2.40SiO2.6La2O3), exhibited a high dielectric constant of ⁓ 9335 and a low dielectric loss of 0.52 at 1 kHz, mainly due to space charge polarization. This makes it a promising candidate for applications in multilayer ceramic capacitors, energy storage, photonics, and electronics. © 2024 Elsevier B.V.
Synthesis, physical, optical and structural properties of SrTiO3 borosilicate glasses with addition of CrO3
(Springer, 2023) Abhishek Madheshiya; Anod Kumar Singh; Shweta; Rajat Kumar Mishra; Krishna Kishor Dey; Manasi Ghosh; Kamal K Srivastava; Prerna Garg; Chandkiram Gautam
Herein, we reported physical, optical and NMR characteristics of SrTiO3-based borosilicate glasses-doped chromium trioxide, CrO3 (1–7 mol%). Five glass samples (GS) were fabricated from the glassy system 60[Sr·TiO3]–40[2SiO2·B2O3] via a rapid melt-quench technique. X-ray diffraction analysis revealed the unstructured behaviour of the glasses. Numerous physical parameters were calculated and explained in detail. Urbach energy (EU) and skin depth (δ) were studied to approve the disordered structure of glasses. Recorded infrared spectra of glasses were utilized to clarify the stretching mode of vibrations between the atoms, which correlated with their structural features and compositional variations. The energy bandgap (Eg) was estimated by employing a Davis and Mott relationship that comprises an absorption coefficient, α, as well as photon energy, hυ. Further, nuclear magnetic resonance (solid-state) spectra of the glasses were recorded and their analysis showed that the silicate and borate networks became highly polymerized with decreasing concentration of SrTiO3. © 2023, Indian Academy of Sciences.
Unveiling of physical, structural, morphological, and electrical properties of Fe2O3doped (30-x)BaO•30TiO2•40SiO2•x[Fe2O3], (0≤x≤6) glass-ceramics potential for energy storage devices
(Elsevier Ltd, 2025) Rajat Kumar Mishra; Sarvesh Kumar Avinashi; Sachin Kumar Yadav; Zaireen Fatima; Rajbala Nain; Rakhi; Savita Kumari; Shweta; Neeraj Mehta; Rakesh Kumar Dwivedi; Chandkiram Gautam
Glass-ceramics with tuneable dielectric properties are increasingly sought after for next-generation multilayer ceramic capacitors (MLCCs) used in advanced electronic applications. However, developing compositions that simultaneously offer high dielectric constants, low dielectric losses, and excellent thermal stability remains a significant challenge. Herein, Fe2O3-doped (30-x)BaO•30TiO2•40SiO2•x[Fe2O3] (0≤x ≤ 6 mol%) glass and glass-ceramics are synthesized using a melt-quenching followed by controlled heat treatment technique. XRD is performed which indicates a transition from amorphous to crystalline structures after heat treatment, with a major phase of tetragonal fresnoite (Ba2TiSi2O8). To check the bonding mechanisms, Fourier transform infrared (FTIR) and Raman spectroscopies are performed. X-ray photoelectron spectroscopy was performed for analysing the elemental composition, and electronic state of a material. However, to study the microstructural behaviour, crystalline nature, and compositional variations, scanning electron microscopy (SEM) and transmission electron microscopy (TEM), followed by energy dispersive spectroscopy (EDS) were also performed. Dielectric properties of the GCs are studied over 10 Hz to 1 MHz. Notably, 24BaO•30TiO2•40SiO2•6Fe2O3(BTSFC6) (x = 6 mol%) sample demonstrates improved dielectric constant (εr = 31740.4) and low dielectric loss (Tanδ = 0.13) at 10 Hz (at 500 °C). The incorporation of Fe2O3not only enhances the AC conductivity but also modifies the electrical relaxation behaviour, as evident from modulus and Cole–Cole plots, which indicate non-Debye-type relaxation and a negative temperature coefficient of resistivity (NTCR) behaviour. Furthermore, hysteresis loop measurements were conducted, revealing that an increase in Fe2O3content in BTSFC glass-ceramics leads to a systematic enhancement in ferroelectric properties and energy storage capacity. This improvement enables material to be tailored for a wide range of applications, from low-loss dielectrics to high-energy storage devices. Therefore, this study demonstrates that strategic Fe2O3doping effectively tailors the structural and dielectric characteristics of barium-titanate silicate glass-ceramics, positioning the BTSFC6 composition as a promising candidate for the fabrication of energy storage devices in demanding thermal and electronic environments. © 2025 Elsevier Ltd and Techna Group S.r.l. All rights are reserved, including those for text and data mining, AI training, and similar technologies.