The success of any implant, dental or orthopaedic, is driven by the interaction of implant materi... more The success of any implant, dental or orthopaedic, is driven by the interaction of implant material with the surrounding tissue. In this context, the nature of the implant surface plays a direct role in determining the long term stability as physico-chemical properties of the surface affect cellular attachment, expression of proteins, and finally osseointegration. Thus to enhance the degree of integration of the implant into the host tissue, various surface modification techniques are employed. In this work, laser surface melting of titanium alloy Ti–6Al–4V was carried out using a CO2 laser with an argon gas atmosphere. Investigations were carried out to study the influence of laser surface modification on the biocompatibility of Ti–6Al–4V alloy implant material. Surface roughness, microhardness, and phase development were recorded. Initial knowledge of these effects on biocompatibility was gained from examination of the response of fibroblast cell lines, which was followed by examination of the response of osteoblast cell lines which is relevant to the applications of this material in bone repair. Biocompatibility with these cell lines was analysed via Resazurin cell viability assay, DNA cell attachment assay, and alamarBlue metabolic activity assay. Laser treated surfaces were found to preferentially promote cell attachment, higher levels of proliferation, and enhanced bioactivity when compared to untreated control samples. These results demonstrate the tremendous potential of this laser surface melting treatment to significantly improve the biocompatibility of titanium implants in vivo.
A novel approach for nanofabricating protein-functionalized luminescent silicon nanoparticles bas... more A novel approach for nanofabricating protein-functionalized luminescent silicon nanoparticles based on infrared ultrafast laser ablation of silicon in an aqueous solution of Staphylococcus aureus protein A is reported. It is demonstrated that 8 nm protein A-capped silicon quantum dots with blue-green photoemissive properties are generated. The conjugation efficiency studies reveal a high percentage of protein A attached to the Si nanoparticle surface through physical adsorption phenomena during the in situ laser process. The biological functionality of laser-generated Staphylococcus aureus protein A-capped Si nanoparticles is investigated. Confocal and electron microscopy together with energy dispersive x-ray spectroscopy analysis show that these Si-based bio-nanostructures selectively bind IgG in the cells. Cell viability studies reveal that these protein A-capped Si nanoparticles are suitable for biological applications, demonstrating their potential as universal secondary biomarkers for in vivo applications such as long-term, real-time cell labeling, cell staining and controlled drug delivery.
Silicon nanoparticles were prepared by ultrafast laser ablation of a silicon target in deionized ... more Silicon nanoparticles were prepared by ultrafast laser ablation of a silicon target in deionized water. The nanoparticles were characterized by using optical absorption, Raman spectroscopy, and transmission electron microscopy. The mean size is found to vary from 60 to 2.5nmin the absence of any reducing chemical reagents, decreasing the pulse energy value. High-resolution transmission electron microscopy to- gether with Raman spectroscopy confirms the crystalline structure of the generated silicon nanoparticles. The energy confinement of carriers which is evaluated from optical experi- ments varies from 90 to 550 meV when the mean nanoparticles size decreases from 60 to 2.5 nm. In particular, the evaluated nanoparticle sizes from optical analysis and the LCAO theoretical model are found in agreement with transmission electron microscopy and Raman measurements for the silicon nanoparticles with a size less than 6 nm. Finally, we present stability studies which show that the smallest nanoparticles aggregate over time.
High-quality carbon nanoparticles with controlled viscosity and high aqueous stability were prepa... more High-quality carbon nanoparticles with controlled viscosity and high aqueous stability were prepared by liquid-phase laser ablation of a graphite target in deionized water. The size distribution was found to vary from 5nm to 50nm with mean size of 18nm, in the absence of any reducing chemical reagents. Efficient generation of short chain polyynes was recorded for high laser repetition rates. Homogeneous and stable nanoparticle suspensions with viscosities ranging from 0.89 to 12mPa.s were obtained by suspending the nanoparticles in different solvent mixtures such as glycerol-water and isopropanol-water. Optical properties were investigated by absorption and photoluminescence spectroscopy. Raman spectroscopy confirmed graphitic-like structure of nanoparticles and the surface chemistry was revealed by Fourier-transform infrared spectroscopy demonstrating sufficient electrostatic stabilization to avoid particle coagulation or flocculation. This paper present an exciting alternative met...
A picosecond laser ablation approach has been developed for the synthesis of ligand-free AuAg bim... more A picosecond laser ablation approach has been developed for the synthesis of ligand-free AuAg bimetallic NPs where the relative amount of Ag is controlled in situ through a laser shielding effect. Various measurements, such as optical spectroscopy, transmission electron microscopy combined with energy dispersive X-ray spectroscopy and inductively coupled plasma optical emission spectrometry, revealed the generation of homogenous 15 nm average size bimetallic NPs with different compositions and tunable localized surface plasmon resonance. Furthermore, ligand-free metallic nanoparticles with respect to chemically synthesized nanoparticles display outstanding properties, i.e. featureless Raman background spectrum, which is a basic requirement in many plasmonic applications such as Surface Enhanced Raman Spectroscopy. Various molecules were chemisorbed on the nanoparticle and SERS investigations were carried out, by varying the laser wavelength. The SERS enhancement factor for AuAg bimetallic NPs shows an enhancement factor of about 5.7 × 10(5) with respect to the flat AuAg surface.
Nanoalloys and nanocomposites are widely studied classes of nanomaterials within the context of b... more Nanoalloys and nanocomposites are widely studied classes of nanomaterials within the context of biological systems. They are of immense interest because of the possibility of tuning the optical, magnetic, electronic and chemical properties through particle composition and internal architecture. In principle these properties can therefore be optimized for application in biological detections such as of DNA sequences, bacteria, viruses, antibodies, antigens, and cancer cells. This article presents an overview of methods currently used for nanoalloy and nanocomposite synthesis and characterisation, focusing on Au–Ag and Fe x O y @Au structures as primary components in detection platforms for plasmo-nic and magnetically enabled plasmonic bio-sensing.
High-quality carbon nanoparticles with controlled viscosity and high aqueous stability were prepa... more High-quality carbon nanoparticles with controlled viscosity and high aqueous stability were prepared by liquid-phase laser ablation of a graphite target in deionized water. The size distribution was found to vary from 5 nm to 50 nm with mean size of 18 nm, in the absence of any reducing chemical reagents. Efficient generation of short chain polyynes was recorded for high laser repetition rates. Homogeneous and stable nanoparticle suspensions with viscosities ranging from 0.89 to 12 mPa.s were obtained by suspending the nanoparticles in different solvent mixtures such as glycerol–water and isopropanol–water. Optical properties were investigated by absorption and photoluminescence spectroscopy. Raman spectroscopy confirmed graphitic-like structure of nanoparticles and the surface chemistry was revealed by Fourier-transform infrared spectroscopy demonstrating sufficient electrostatic stabilization to avoid particle coagulation or flocculation. This paper present an exciting alternative method to engineer carbon nano-particles and their potential use as a ligand-free nano-ink for ink jet printing (jetting) applications.
The success of any implant, dental or orthopaedic, is driven by the interaction of implant materi... more The success of any implant, dental or orthopaedic, is driven by the interaction of implant material with the surrounding tissue. In this context, the nature of the implant surface plays a direct role in determining the long term stability as physico-chemical properties of the surface affect cellular attachment, expression of proteins, and finally osseointegration. Thus to enhance the degree of integration of the implant into the host tissue, various surface modification techniques are employed. In this work, laser surface melting of titanium alloy Ti–6Al–4V was carried out using a CO2 laser with an argon gas atmosphere. Investigations were carried out to study the influence of laser surface modification on the biocompatibility of Ti–6Al–4V alloy implant material. Surface roughness, microhardness, and phase development were recorded. Initial knowledge of these effects on biocompatibility was gained from examination of the response of fibroblast cell lines, which was followed by examination of the response of osteoblast cell lines which is relevant to the applications of this material in bone repair. Biocompatibility with these cell lines was analysed via Resazurin cell viability assay, DNA cell attachment assay, and alamarBlue metabolic activity assay. Laser treated surfaces were found to preferentially promote cell attachment, higher levels of proliferation, and enhanced bioactivity when compared to untreated control samples. These results demonstrate the tremendous potential of this laser surface melting treatment to significantly improve the biocompatibility of titanium implants in vivo.
Laser-based Micro- and Nanoprocessing IX, Mar 12, 2015
Direct-write laser processing has been demonstrated to be capable of both surface patterning of m... more Direct-write laser processing has been demonstrated to be capable of both surface patterning of micro- and nanoscale structures on polymer surfaces without significant modification of the surface chemistry or optical transmission of the laser processed area. In this work, the creation of microchannels via direct-write laser processing of 188 μm thickness cyclic olefin polymers is demonstrated, along with a route towards channel functionalization. Cyclic olefin polymers (COP) are an emerging class of polymers noted for their high chemical resistance, biocompatibility and higher optical transparency when compared to other common polymers. These properties make them excellent substrates for the fabrication of microfluidic devices. This paper presents the first investigation into infrared laser processing of COP using a 1064 nm Nd:YAG laser. Scanning electron microscopy and Raman spectroscopy were utilized to investigate the morphology and composition of these laser textured surfaces.
The success of any implant, dental or orthopaedic, is driven by the interaction of implant materi... more The success of any implant, dental or orthopaedic, is driven by the interaction of implant material with the surrounding tissue. In this context, the nature of the implant surface plays a direct role in determining the long term stability as physico-chemical properties of the surface affect cellular attachment, expression of proteins, and finally osseointegration. Thus to enhance the degree of integration of the implant into the host tissue, various surface modification techniques are employed. In this work, laser surface melting of titanium alloy Ti–6Al–4V was carried out using a CO2 laser with an argon gas atmosphere. Investigations were carried out to study the influence of laser surface modification on the biocompatibility of Ti–6Al–4V alloy implant material. Surface roughness, microhardness, and phase development were recorded. Initial knowledge of these effects on biocompatibility was gained from examination of the response of fibroblast cell lines, which was followed by examination of the response of osteoblast cell lines which is relevant to the applications of this material in bone repair. Biocompatibility with these cell lines was analysed via Resazurin cell viability assay, DNA cell attachment assay, and alamarBlue metabolic activity assay. Laser treated surfaces were found to preferentially promote cell attachment, higher levels of proliferation, and enhanced bioactivity when compared to untreated control samples. These results demonstrate the tremendous potential of this laser surface melting treatment to significantly improve the biocompatibility of titanium implants in vivo.
A novel approach for nanofabricating protein-functionalized luminescent silicon nanoparticles bas... more A novel approach for nanofabricating protein-functionalized luminescent silicon nanoparticles based on infrared ultrafast laser ablation of silicon in an aqueous solution of Staphylococcus aureus protein A is reported. It is demonstrated that 8 nm protein A-capped silicon quantum dots with blue-green photoemissive properties are generated. The conjugation efficiency studies reveal a high percentage of protein A attached to the Si nanoparticle surface through physical adsorption phenomena during the in situ laser process. The biological functionality of laser-generated Staphylococcus aureus protein A-capped Si nanoparticles is investigated. Confocal and electron microscopy together with energy dispersive x-ray spectroscopy analysis show that these Si-based bio-nanostructures selectively bind IgG in the cells. Cell viability studies reveal that these protein A-capped Si nanoparticles are suitable for biological applications, demonstrating their potential as universal secondary biomarkers for in vivo applications such as long-term, real-time cell labeling, cell staining and controlled drug delivery.
Silicon nanoparticles were prepared by ultrafast laser ablation of a silicon target in deionized ... more Silicon nanoparticles were prepared by ultrafast laser ablation of a silicon target in deionized water. The nanoparticles were characterized by using optical absorption, Raman spectroscopy, and transmission electron microscopy. The mean size is found to vary from 60 to 2.5nmin the absence of any reducing chemical reagents, decreasing the pulse energy value. High-resolution transmission electron microscopy to- gether with Raman spectroscopy confirms the crystalline structure of the generated silicon nanoparticles. The energy confinement of carriers which is evaluated from optical experi- ments varies from 90 to 550 meV when the mean nanoparticles size decreases from 60 to 2.5 nm. In particular, the evaluated nanoparticle sizes from optical analysis and the LCAO theoretical model are found in agreement with transmission electron microscopy and Raman measurements for the silicon nanoparticles with a size less than 6 nm. Finally, we present stability studies which show that the smallest nanoparticles aggregate over time.
High-quality carbon nanoparticles with controlled viscosity and high aqueous stability were prepa... more High-quality carbon nanoparticles with controlled viscosity and high aqueous stability were prepared by liquid-phase laser ablation of a graphite target in deionized water. The size distribution was found to vary from 5nm to 50nm with mean size of 18nm, in the absence of any reducing chemical reagents. Efficient generation of short chain polyynes was recorded for high laser repetition rates. Homogeneous and stable nanoparticle suspensions with viscosities ranging from 0.89 to 12mPa.s were obtained by suspending the nanoparticles in different solvent mixtures such as glycerol-water and isopropanol-water. Optical properties were investigated by absorption and photoluminescence spectroscopy. Raman spectroscopy confirmed graphitic-like structure of nanoparticles and the surface chemistry was revealed by Fourier-transform infrared spectroscopy demonstrating sufficient electrostatic stabilization to avoid particle coagulation or flocculation. This paper present an exciting alternative met...
A picosecond laser ablation approach has been developed for the synthesis of ligand-free AuAg bim... more A picosecond laser ablation approach has been developed for the synthesis of ligand-free AuAg bimetallic NPs where the relative amount of Ag is controlled in situ through a laser shielding effect. Various measurements, such as optical spectroscopy, transmission electron microscopy combined with energy dispersive X-ray spectroscopy and inductively coupled plasma optical emission spectrometry, revealed the generation of homogenous 15 nm average size bimetallic NPs with different compositions and tunable localized surface plasmon resonance. Furthermore, ligand-free metallic nanoparticles with respect to chemically synthesized nanoparticles display outstanding properties, i.e. featureless Raman background spectrum, which is a basic requirement in many plasmonic applications such as Surface Enhanced Raman Spectroscopy. Various molecules were chemisorbed on the nanoparticle and SERS investigations were carried out, by varying the laser wavelength. The SERS enhancement factor for AuAg bimetallic NPs shows an enhancement factor of about 5.7 × 10(5) with respect to the flat AuAg surface.
Nanoalloys and nanocomposites are widely studied classes of nanomaterials within the context of b... more Nanoalloys and nanocomposites are widely studied classes of nanomaterials within the context of biological systems. They are of immense interest because of the possibility of tuning the optical, magnetic, electronic and chemical properties through particle composition and internal architecture. In principle these properties can therefore be optimized for application in biological detections such as of DNA sequences, bacteria, viruses, antibodies, antigens, and cancer cells. This article presents an overview of methods currently used for nanoalloy and nanocomposite synthesis and characterisation, focusing on Au–Ag and Fe x O y @Au structures as primary components in detection platforms for plasmo-nic and magnetically enabled plasmonic bio-sensing.
High-quality carbon nanoparticles with controlled viscosity and high aqueous stability were prepa... more High-quality carbon nanoparticles with controlled viscosity and high aqueous stability were prepared by liquid-phase laser ablation of a graphite target in deionized water. The size distribution was found to vary from 5 nm to 50 nm with mean size of 18 nm, in the absence of any reducing chemical reagents. Efficient generation of short chain polyynes was recorded for high laser repetition rates. Homogeneous and stable nanoparticle suspensions with viscosities ranging from 0.89 to 12 mPa.s were obtained by suspending the nanoparticles in different solvent mixtures such as glycerol–water and isopropanol–water. Optical properties were investigated by absorption and photoluminescence spectroscopy. Raman spectroscopy confirmed graphitic-like structure of nanoparticles and the surface chemistry was revealed by Fourier-transform infrared spectroscopy demonstrating sufficient electrostatic stabilization to avoid particle coagulation or flocculation. This paper present an exciting alternative method to engineer carbon nano-particles and their potential use as a ligand-free nano-ink for ink jet printing (jetting) applications.
The success of any implant, dental or orthopaedic, is driven by the interaction of implant materi... more The success of any implant, dental or orthopaedic, is driven by the interaction of implant material with the surrounding tissue. In this context, the nature of the implant surface plays a direct role in determining the long term stability as physico-chemical properties of the surface affect cellular attachment, expression of proteins, and finally osseointegration. Thus to enhance the degree of integration of the implant into the host tissue, various surface modification techniques are employed. In this work, laser surface melting of titanium alloy Ti–6Al–4V was carried out using a CO2 laser with an argon gas atmosphere. Investigations were carried out to study the influence of laser surface modification on the biocompatibility of Ti–6Al–4V alloy implant material. Surface roughness, microhardness, and phase development were recorded. Initial knowledge of these effects on biocompatibility was gained from examination of the response of fibroblast cell lines, which was followed by examination of the response of osteoblast cell lines which is relevant to the applications of this material in bone repair. Biocompatibility with these cell lines was analysed via Resazurin cell viability assay, DNA cell attachment assay, and alamarBlue metabolic activity assay. Laser treated surfaces were found to preferentially promote cell attachment, higher levels of proliferation, and enhanced bioactivity when compared to untreated control samples. These results demonstrate the tremendous potential of this laser surface melting treatment to significantly improve the biocompatibility of titanium implants in vivo.
Laser-based Micro- and Nanoprocessing IX, Mar 12, 2015
Direct-write laser processing has been demonstrated to be capable of both surface patterning of m... more Direct-write laser processing has been demonstrated to be capable of both surface patterning of micro- and nanoscale structures on polymer surfaces without significant modification of the surface chemistry or optical transmission of the laser processed area. In this work, the creation of microchannels via direct-write laser processing of 188 μm thickness cyclic olefin polymers is demonstrated, along with a route towards channel functionalization. Cyclic olefin polymers (COP) are an emerging class of polymers noted for their high chemical resistance, biocompatibility and higher optical transparency when compared to other common polymers. These properties make them excellent substrates for the fabrication of microfluidic devices. This paper presents the first investigation into infrared laser processing of COP using a 1064 nm Nd:YAG laser. Scanning electron microscopy and Raman spectroscopy were utilized to investigate the morphology and composition of these laser textured surfaces.
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Papers by Dr Komal Bagga
employed. In this work, laser surface melting of titanium alloy Ti–6Al–4V was carried out using a CO2 laser with an argon gas atmosphere. Investigations were carried out to study the influence of laser surface modification on the biocompatibility of Ti–6Al–4V alloy implant material. Surface roughness, microhardness, and phase development were recorded. Initial knowledge of these effects on biocompatibility was gained from examination of the response of fibroblast cell lines, which was followed by examination of the response of osteoblast cell lines which is relevant to the applications of this material in bone repair. Biocompatibility with these cell lines was analysed via Resazurin cell viability assay, DNA cell attachment assay, and alamarBlue metabolic activity assay. Laser treated surfaces were found to preferentially promote cell attachment, higher levels of proliferation, and enhanced bioactivity when compared to untreated control samples. These results demonstrate the tremendous potential of this laser surface melting treatment to significantly improve the biocompatibility of titanium implants in vivo.
2015 by Dr Komal Bagga
2014 by Dr Komal Bagga
on biocompatibility was gained from examination of the response of fibroblast cell lines, which was followed by examination of the response of osteoblast cell lines which is relevant to the applications of this material in bone repair. Biocompatibility with these cell lines was analysed via Resazurin cell viability assay, DNA cell attachment assay, and alamarBlue metabolic activity assay. Laser treated surfaces were found to preferentially promote cell attachment, higher levels of proliferation, and enhanced bioactivity when compared to untreated control samples. These results demonstrate
the tremendous potential of this laser surface melting treatment to significantly improve the biocompatibility of titanium implants in vivo.
Conference Papers by Dr Komal Bagga
A route for functionalization of these substrates for chemical and biological speciation and separation was examined using carbon nanoparticles. The nanoparticles were produced using pulsed laser ablation in liquid (PLAL) which has been reported as a fast and adaptable method for nanoparticle production. The nanoparticles produced were using transmission electron microscopy while the coating of substrates with these CNPs was examined using SEM. These results are discussed in the context of development of a new route for achieving surfaces optimized for microfluidicbased separations and speciation. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
employed. In this work, laser surface melting of titanium alloy Ti–6Al–4V was carried out using a CO2 laser with an argon gas atmosphere. Investigations were carried out to study the influence of laser surface modification on the biocompatibility of Ti–6Al–4V alloy implant material. Surface roughness, microhardness, and phase development were recorded. Initial knowledge of these effects on biocompatibility was gained from examination of the response of fibroblast cell lines, which was followed by examination of the response of osteoblast cell lines which is relevant to the applications of this material in bone repair. Biocompatibility with these cell lines was analysed via Resazurin cell viability assay, DNA cell attachment assay, and alamarBlue metabolic activity assay. Laser treated surfaces were found to preferentially promote cell attachment, higher levels of proliferation, and enhanced bioactivity when compared to untreated control samples. These results demonstrate the tremendous potential of this laser surface melting treatment to significantly improve the biocompatibility of titanium implants in vivo.
on biocompatibility was gained from examination of the response of fibroblast cell lines, which was followed by examination of the response of osteoblast cell lines which is relevant to the applications of this material in bone repair. Biocompatibility with these cell lines was analysed via Resazurin cell viability assay, DNA cell attachment assay, and alamarBlue metabolic activity assay. Laser treated surfaces were found to preferentially promote cell attachment, higher levels of proliferation, and enhanced bioactivity when compared to untreated control samples. These results demonstrate
the tremendous potential of this laser surface melting treatment to significantly improve the biocompatibility of titanium implants in vivo.
A route for functionalization of these substrates for chemical and biological speciation and separation was examined using carbon nanoparticles. The nanoparticles were produced using pulsed laser ablation in liquid (PLAL) which has been reported as a fast and adaptable method for nanoparticle production. The nanoparticles produced were using transmission electron microscopy while the coating of substrates with these CNPs was examined using SEM. These results are discussed in the context of development of a new route for achieving surfaces optimized for microfluidicbased separations and speciation. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.