Prasoon Kumar

Tissue engineering is a systematic approach of assembling cells onto a 3D scaffold to form a functional tissue in the presence of critical growth factors. The scaffolding system guides stem cells through topological, physiochemical, and mechanical cues to differentiate and integrate to form a functional tissue. However, cellular communication during tissue formation taking place in a reactor needs to be understood properly to enable appropriate positioning of the cells in a 3D environment… Show more

Tissue engineering is a systematic approach of assembling cells onto a 3D scaffold to form a functional tissue in the presence of critical growth factors. The scaffolding system guides stem cells through topological, physiochemical, and mechanical cues to differentiate and integrate to form a functional tissue. However, cellular communication during tissue formation taking place in a reactor needs to be understood properly to enable appropriate positioning of the cells in a 3D environment. Hence, sensors and actuators integrated with cyber-physical system (CPS) may be able to sense the tissue microenvironment and direct cells/cellular aggregates to an appropriate position, respectively. This can facilitate better cell-to-cell communication and cell–extracellular matrix communication for proper tissue morphogenesis. Advancements are made in the field of smart scaffolds that can morph cells/cellular aggregates after sensing the cellular microenvironment in a desired 3D architecture by providing appropriate cues. Recent scientific developments in the additive manufacturing technology have enabled the fabrication of smart scaffolds to create structural and functional tissue constructs. Sensors/actuators, cyber-systems, smart materials, and additive manufacturing put together is expected to lead to improved tissue-engineered medical products. The present review aims to highlight the possibilities of advancement of BioCPS for tissue engineering and regenerative medicine. Show less

New sensors, sensing schemes, and sensor materials have revolutionized the field of personalized diagnostics. Functional, biocompatible, and flexible materials have spearheaded the development of various wearable and implantable sensors over the last decade. The present-day sensors may be integrated into the patient's body and monitor the desired physiological parameters in real time. This has been achieved by hybrid biomaterials that exhibit enhanced electrical, mechanical, magnetic, and… Show more

New sensors, sensing schemes, and sensor materials have revolutionized the field of personalized diagnostics. Functional, biocompatible, and flexible materials have spearheaded the development of various wearable and implantable sensors over the last decade. The present-day sensors may be integrated into the patient's body and monitor the desired physiological parameters in real time. This has been achieved by hybrid biomaterials that exhibit enhanced electrical, mechanical, magnetic, and chemical properties when compared with the conventional biomaterials. These materials are developed through surface modification and doping with nanomaterials, rendering them amenable for any biosensor development. These sensors are also capable of seamlessly transmitting the acquired data to specific recipients using advanced electronics. In this article, we have presented a review of some of the recent advancements in the domains of neural, cardiovascular, metabolic, and musculoskeletal sensor systems, which have seen significant developments in the recent times. Show less

Cell immobilization is the process of localizing intact cells onto specific regions in a device or material without the loss of requisite biological function. Immobilization of cells can generally be performed through physical adsorption, encapsulation, entrapment and self-aggregation. Various types of cells, including microbial, plant, mammalian and insect cells, have been immobilized on materials for improving the bio-synthesis, bioanalytics, as well as cell therapy applications. Recently… Show more

Cell immobilization is the process of localizing intact cells onto specific regions in a device or material without the loss of requisite biological function. Immobilization of cells can generally be performed through physical adsorption, encapsulation, entrapment and self-aggregation. Various types of cells, including microbial, plant, mammalian and insect cells, have been immobilized on materials for improving the bio-synthesis, bioanalytics, as well as cell therapy applications. Recently, cell immobilization on biomaterials-based 3-D scaffolds has gained attention in the area of regenerative medicine and tissue engineering wherein the transplantation of immobilized cells has been utilized in repair, restoration or improvement of tissue function. This chapter will majorly focus on different mammalian cell immobilization techniques, physio-chemical properties of matrix materials employed for cell immobilization and their applications in tissue engineering. Show less

The gut microbiome comprises a variety of microorganisms whose genes encode proteins to carry out crucial metabolic functions that are responsible for the majority of health-related issues in human beings. The advent of the technological revolution in artificial intelligence (AI) assisted synthetic biology (SB) approaches will play a vital role in the modulating the therapeutic and nutritive potential of probiotics. This can turn human gut as a reservoir of beneficial bacterial colonies having… Show more

The gut microbiome comprises a variety of microorganisms whose genes encode proteins to carry out crucial metabolic functions that are responsible for the majority of health-related issues in human beings. The advent of the technological revolution in artificial intelligence (AI) assisted synthetic biology (SB) approaches will play a vital role in the modulating the therapeutic and nutritive potential of probiotics. This can turn human gut as a reservoir of beneficial bacterial colonies having an immense role in immunity, digestion, brain function, and other health benefits. Hence, in the present review, we have discussed the role of several gene editing tools and approaches in synthetic biology that have equipped us with novel tools like Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR-Cas) systems to precisely engineer probiotics for diagnostic, therapeutic and nutritive value. A brief discussion over the AI techniques to understand the metagenomic data from the healthy and diseased gut microbiome is also presented. Further, the role of AI in potentially impacting the pace of developments in SB and its current challenges is also discussed. The review also describes the health benefits conferred by engineered microbes through the production of biochemicals, nutraceuticals, drugs or biotherapeutics molecules etc. Finally, the review concludes with the challenges and regulatory concerns in adopting synthetic biology engineered microbes for clinical applications. Thus, the review presents a synergistic approach of AI and SB toward human gut microbiome for better health which will provide interesting clues to researchers working in the area of rapidly evolving food and nutrition science. Show less

In the past few decades, dried blood matrix biosampling has witnessed a marvelous interest among the researcher due to its user-friendly operation during blood sampling in preclinical and clinical applications. It also complies with the basic 3Rs (reduce, reuse and recycle) philosophy. Because of comparative simplicity, a huge number of researchers are paying attention to its technological advancements for widespread application in the bioanalysis and diagnosis arena. In this review, we have… Show more

In the past few decades, dried blood matrix biosampling has witnessed a marvelous interest among the researcher due to its user-friendly operation during blood sampling in preclinical and clinical applications. It also complies with the basic 3Rs (reduce, reuse and recycle) philosophy. Because of comparative simplicity, a huge number of researchers are paying attention to its technological advancements for widespread application in the bioanalysis and diagnosis arena. In this review, we have explained different approaches to be considered during dried blood matrix based microsampling including their clinical relevance in therapeutic drug monitoring. We have also discussed various strategies for avoiding and minimizing major unwanted analytical interferences associated with this technique during drug quantification. Further, various recent technological advancement in microsampling devices has been discussed correlating their clinical applications. Show less

Rapid and even spreading of complex fluids over a large area on substrates like paper is required for chemical and biological sensing applications. Non-Newtonian flow behavior and the presence of multi-phase components pose a significant challenge to uniform flow in porous media. Specifically in the case of blood, for biosensing applications, fast spread on a large area is required to avoid coagulation and non-uniform component spread. In this work, we have developed a filter paper-based device… Show more

Rapid and even spreading of complex fluids over a large area on substrates like paper is required for chemical and biological sensing applications. Non-Newtonian flow behavior and the presence of multi-phase components pose a significant challenge to uniform flow in porous media. Specifically in the case of blood, for biosensing applications, fast spread on a large area is required to avoid coagulation and non-uniform component spread. In this work, we have developed a filter paper-based device to resolve this spreading challenge. We sandwich the filter paper between a matrix of nanofibrous membrane backed by polyethylene terephthalate (PET) sheets, forming a multi-scale porous network: one within the filter paper and the other between the PET sheet and the filter paper. By doing so, we decrease the overall resistance to flow while maintaining the same capillary suction pressure to obtain a quick, uniform spread of dyed liquids, milk solutions, and whole blood. The device design and concepts used here can be used in paper microfluidic applications and to develop devices for dried blood spot analysis, which utilize this fast flow while maintaining even spreading over a large area. Show less

Significant research and development in the field of biomedical implants has evoked the
scope to treat a broad range of orthopedic ailments that include fracture fixation, total bone replacement,
joint arthrodesis, dental screws, and others. Importantly, the success of a bioimplant depends not
only upon its bulk properties, but also on its surface properties that influence its interaction with the
host tissue. Various approaches of surface modification such as coating of… Show more

Significant research and development in the field of biomedical implants has evoked the
scope to treat a broad range of orthopedic ailments that include fracture fixation, total bone replacement,
joint arthrodesis, dental screws, and others. Importantly, the success of a bioimplant depends not
only upon its bulk properties, but also on its surface properties that influence its interaction with the
host tissue. Various approaches of surface modification such as coating of nanomaterial have been
employed to enhance antibacterial activities of a bioimplant. The modified surface facilitates directed
modulation of the host cellular behavior and grafting of cell-binding peptides, extracellular matrix
(ECM) proteins, and growth factors to further improve host acceptance of a bioimplant. These strategies
showed promising results in orthopedics, e.g., improved bone repair and regeneration. However,
the choice of materials, especially considering their degradation behavior and surface properties, plays
a key role in long-term reliability and performance of bioimplants. Metallic biomaterials have evolved
largely in terms of their bulk and surface properties including nano-structuring with nanomaterials to
meet the requirements of new generation orthopedic bioimplants. In this review, we have discussed
metals and metal alloys commonly used for manufacturing different orthopedic bioimplants and the
biotic as well as abiotic factors affecting the failure and degradation of those bioimplants. The review
also highlights the currently available nanomaterial-based surface modification technologies to
augment the function and performance of these metallic bioimplants in a clinical setting. Show less

A micropump is the heart of any microfluidic device that finds applications in several lab-on-chip devices. Passive micropumps are highly desirable for this purpose due to their ease of integration, low energy requirements, and simplistic design and operation. The design of a plant leaf serves as natural inspiration for the development of an evaporation-assisted passive micropump. The presence of a branching-channel-like venation pattern ensures water distribution to the spongy mesophyll cells,… Show more

A micropump is the heart of any microfluidic device that finds applications in several lab-on-chip devices. Passive micropumps are highly desirable for this purpose due to their ease of integration, low energy requirements, and simplistic design and operation. The design of a plant leaf serves as natural inspiration for the development of an evaporation-assisted passive micropump. The presence of a branching-channel-like venation pattern ensures water distribution to the spongy mesophyll cells, increasing the surface area for evaporation. However, because of its multiscale design and the complexity of the venation pattern, emulating a leaf’s design is challenging. Apart from the lack of understanding of design parameters that affect fluid flow, manufacturing limitations impede the development of such bioinspired micropumps. Inspired by the multiscale design of the leaf, in this work we propose a passive micropump mimicking the structure of a leaf. Using evaporation and capillary pressure as the pumping mechanism, our leaf-mimicking micropump consists of a microporous membrane integrated with a branched, fractal channel network resembling a leaf’s venation pattern. Our proposed fabrication method is simple, scalable, and inexpensive and uses readily available materials. We demonstrate a significant increase in the fluid flow rate due to the addition of this branched-channel network. We support our experimental observations using an analytical model, wherein we discuss the design parameters that affect the pumping rate. Correspondingly, the performance of these micropumps can be optimized on the basis of intrinsic and extrinsic factors as per the desired applications. Show less

Blood microsampling is desired in clinical, pharmaceutical and biomedical fields to overcome the challenges of conventional whole blood sampling. One of the popular methods for blood microsampling is the dried blood spot (DBS) kit and the collected sample is subsequently used for bioanalysis. The current practice of DBS is simple to use, cheap and very well standardized from sample collection to analysis. However, DBS suffers from several well documented challenges related to blood spot… Show more

Blood microsampling is desired in clinical, pharmaceutical and biomedical fields to overcome the challenges of conventional whole blood sampling. One of the popular methods for blood microsampling is the dried blood spot (DBS) kit and the collected sample is subsequently used for bioanalysis. The current practice of DBS is simple to use, cheap and very well standardized from sample collection to analysis. However, DBS suffers from several well documented challenges related to blood spot formation such as varying hematocrit volume, thin layer chromatography effect and subsequent bio-analysis resulting in a variable and ocassionally high failure rate. A major source of these problems is our limited understanding of blood flow in porous media under different ambient and material conditions. Therefore, it is highly desirable to understand the parameters that affect blood flow in a porous medium to enable a more robust design of DBS and generally blood microsampling kits. In this review, we discuss some existing blood microsampling techniques while focusing on the challenges associated with blood flow dynamics. We also review existing studies on the potential factors that affect the permeation (imbibition or wicking) and spreading of blood in a thin, porous substrate as means to understand and overcome the challenges in designing new DBS kits and blood microsampling devices. Thereafter, we have discussed recent advances in the design of passive flow-based devices to overcome these challenges of current blood microsampling by DBS. Finally, we present a few applications of DBS in clinical and non-clinical studies. This review can benefit researchers working at the interface of complex fluid flow, surface chemistry, and material and device design for biomedical and biological applications. Show less

Digitalization of health care practices is substantially manifesting itself as an effective tool to diagnose and rectify complex cardiovascular abnormalities. For cardiovascular abnormalities, precise non-invasive imaging interventions are being used to develop patient specific diagnosis and surgical planning. Concurrently, pre surgical 3D simulation and computational modeling are aiding in the effective surgery and understanding of valve biomechanics, respectively. Consequently, 3D printing of… Show more

Digitalization of health care practices is substantially manifesting itself as an effective tool to diagnose and rectify complex cardiovascular abnormalities. For cardiovascular abnormalities, precise non-invasive imaging interventions are being used to develop patient specific diagnosis and surgical planning. Concurrently, pre surgical 3D simulation and computational modeling are aiding in the effective surgery and understanding of valve biomechanics, respectively. Consequently, 3D printing of patient specific valves that can mimic the original one will become an effective outbreak for valvular problems. Printing of these patient-specific tissues or organ components is becoming a viable option owing to the advances in biomaterials and additive manufacturing techniques. These additive manufacturing techniques are receiving a full-fledged support from burgeoning field of computational fluid dynamics, digital image processing, artificial intelligence, and continuum mechanics during their optimization and implementation. Further, studies at cellular and molecular biomechanics have enriched our understanding of biomechanical factors resulting in valvular heart diseases. Hence, the knowledge generated can guide us during the design and synthesis of biomaterials to develop superior extra cellular matrix, mimicking materials that can be used as a bioink for 3D printing of organs and tissues. With this notion, we have reviewed current opportunities and challenges in the diagnosis and treatment of heart valve abnormalities through patient-specific valve design via tissue engineering and 3D bioprinting. These valves can replace diseased valves by preserving homogeneity and individuality of the patients. Show less

An effective method has been proposed for controlling the size distributions of metallic nanoparticles produced through laser ablation in liquid by employing physical boundaries in the vicinity of the ablation site. An Nd:YAG laser (1064 nm, FWHM 6 ns) has been used to ablate the copper target immersed in two different liquid medium, water and isopropyl alcohol. Water and isopropyl alcohol have been chosen because of the significant differences in their densities while the optical properties… Show more

An effective method has been proposed for controlling the size distributions of metallic nanoparticles produced through laser ablation in liquid by employing physical boundaries in the vicinity of the ablation site. An Nd:YAG laser (1064 nm, FWHM 6 ns) has been used to ablate the copper target immersed in two different liquid medium, water and isopropyl alcohol. Water and isopropyl alcohol have been chosen because of the significant differences in their densities while the optical properties are nearly comparable. To demonstrate the efficacy of the method, experiments have been conducted in both the configurations, that is, with and without confining boundaries. To ascertain the observed effect, select experiments have also been carried out with gold as the target material to ensure that the size distribution is not influenced because of oxide-layer formation. The size of the particles were estimated from the SEM images and analysing these images using an indigenously developed code. It has been observed that there are significant differences in the size distributions in the cases of nanoparticles produced with and without confining boundaries. For any given medium, a consistent increase in the mean size of the nanoparticles produced with the targets fitted with physical boundary has been observed as compared to those produced with flat targets. The observed trend has been attributed to the plausible role of the shock wave reflection from the physical boundaries, which alters the plasma parameters. Reflected shock wave–plasma interactions prolonging the thermalisation time of the plasma plume in confined geometry facilitate the particle growth, resulting in the formation of bigger particles. The proposed method, which can be applied to any metallic target, is one of the greener methods for producing nanoparticles and is also relatively simple and cost effective. Show less

Multi scale fractal morphology communicating with nanoscale phenomena is commonly observed in nature in several applications including leaf, fish gill, respiratory systems, and so on. Recent investigations on bio-mimicking these morphologies confirm their effectiveness in several bio-applications including heat and mass transfer, tissue engineering, capillary pump, and self-healing materials. A scalable, lithography-less process of fabricating such fractal channels in micro-meso sizes connected… Show more

Multi scale fractal morphology communicating with nanoscale phenomena is commonly observed in nature in several applications including leaf, fish gill, respiratory systems, and so on. Recent investigations on bio-mimicking these morphologies confirm their effectiveness in several bio-applications including heat and mass transfer, tissue engineering, capillary pump, and self-healing materials. A scalable, lithography-less process of fabricating such fractal channels in micro-meso sizes connected to vascular nano-network is proposed here. A recently developed, novel method for ultra-fast fabrication of fractal microstructure is integrated with electropsun nanofibrous network to form sacrificial core structures. These structures are embedded in a thin PDMS matrix and channel networks are generated by removal of sacrificial elements using solvents. Eventually, these structures are characterized and preliminary studies demonstrate their effectiveness in mass transport application. Show less

Polymeric electrospun fibers have the potential to be utilized for a variety of applications such as tissue engineering, biomedicine, filtration, biosensors, and textiles, owing to their high aspect ratio and high surface area per unit mass. However, these applications have some form of dependency on the mechanical properties of fiber meshes. Therefore, the current study is aimed at understanding the mechanical behavior of electrospun fiber systems at different length scales in order to… Show more

Polymeric electrospun fibers have the potential to be utilized for a variety of applications such as tissue engineering, biomedicine, filtration, biosensors, and textiles, owing to their high aspect ratio and high surface area per unit mass. However, these applications have some form of dependency on the mechanical properties of fiber meshes. Therefore, the current study is aimed at understanding the mechanical behavior of electrospun fiber systems at different length scales in order to establish a correlation between their structure and mechanical properties. Micro-/nano-fiber meshes of polystyrene were fabricated by the process of electrospinning and were subjected to uni-axial tensile testing. High-resolution imaging during tensile testing revealed the macroscopic and microscopic structural evolution of these fibers. Further, we also experimentally observed the dependence of tensile strength, % elongation and toughness of fiber meshes on the orientation of the fibers. The continuum mechanics simulation studies of fiber meshes with different orientations corroborated well with our experimental studies. Comprehensively, these studies demonstrated the changes in mechanical behavior of electrospun fiber meshes owing to the re-orientation and alignment of fibers in meshes at microscopic and macroscopic length scale during tensile testing. Such in-depth analysis of fiber alignment on the mechanics of fiber mesh can be exploited for the design and fabrication of tissue engineering scaffolds for load-bearing tissues, composites for impact applications, and textiles Show less

Gills are one of the most primitive gas, solute exchange organs available in fishes. They facilitate exchange of gases, solutes and ions with a surrounding water medium through their functional unit called secondary lamella. These lamellae through their extraordinary morphometric features and peculiar arrangement in gills, achieve remarkable mass transport properties. Therefore, in the current study, modeling and simulation of convection-diffusion transport through a two dimensional model of… Show more

Gills are one of the most primitive gas, solute exchange organs available in fishes. They facilitate exchange of gases, solutes and ions with a surrounding water medium through their functional unit called secondary lamella. These lamellae through their extraordinary morphometric features and peculiar arrangement in gills, achieve remarkable mass transport properties. Therefore, in the current study, modeling and simulation of convection-diffusion transport through a two dimensional model of secondary lamella and theoretical analysis of morphometric features of fish gills were carried out. Such study suggested an evolutionary conservation of parametric ratios across fishes of different weights. Further, we have also fabricated a thin microvascularised PDMS matrices mimicking secondary lamella by use of micro-technologies like electrospinning. In addition, we have also demonstrated the fluid flow by capillary action through these thin microvascularised PDMS matrices. Eventually, we also illustrated the application of these thin microvascularied PDMS matrices in solute exchange process under capillary flow conditions. Thus, our study suggested that fish gills have optimized parameteric ratios, at multiple length scale, throughout an evolution to achieve an organ with enhanced mass transport capabilities. Thus, these defined parametric ratios could be exploited to design and develop efficient, scaled-up gas/solute exchange microdevices. We also proposed an inexpensive and scalable method of fabrication of thin microvascularised polymer matrices and demonstrated its solute exchange capabilities under capillary flow conditions. Thus, mimicking the microstructures of secondary lamella will enable fabrication of microvascularised thin polymer systems through micro manufacturing technologies for potential applications in filtration, self-healing/cooling materials and bioengineering. Show less

Integrated micro-nanochannel networks in fluidic devices are desirable in a number of applications ranging from self-healing/cooling materials to bioengineering. The conventional micro-manufacturing techniques are capable of either producing microchannel or nanochannel networks for a fluidic application but lack proficiency in the production of an integrated micro-nanochannel network with a smooth transition from micro-to-nano scale dimension. In addition, these techniques possess limitations… Show more

Integrated micro-nanochannel networks in fluidic devices are desirable in a number of applications ranging from self-healing/cooling materials to bioengineering. The conventional micro-manufacturing techniques are capable of either producing microchannel or nanochannel networks for a fluidic application but lack proficiency in the production of an integrated micro-nanochannel network with a smooth transition from micro-to-nano scale dimension. In addition, these techniques possess limitations such as heavy initial investment, sophistication in operation and scale-up capabilities. Therefore, the current paper demonstrates the combination of micro/nanotechnologies to design and develop a biomimetic 3-D integrated micro-nanochannel network in PDMS device for solute exchange. We have used 3-D printer, a scalable technology, to design and manufacture micro-mold having fractal-shaped features. Further, electrospinning was used to deposit nanofibrous network on the fractal mold. Subsequent micro-molding with PDMS was used to obtain fractal-shaped microchannels integrated with embedded nanofibers. Henceforth, solvent etching of nanofibers followed by bonding of thin PDMS membrane generated by spin coating to open end of channels leads to the formation of functional microdevices. These PDMS devices mimic the natural vasculature of a living system, where fractal-shaped microchannels will assist in efficient fluid flow and the site of nanovascular network participates in heat/mass transport operations. Further, dye flow propounds the functionality of such devices. Our study hence proposes a simple and scalable hybrid microtechnolgy to fabricate fluidic devices having multiscale architecture. This will also facilitate the rapid fabrication of microfluidic devices for biomedical, diagnostics, sensors and micro-TAS applications. Show less

Three-dimensional (3D) micro/nanofluidic devices can accelerate progress in numerous fields such as tissue engineering, drug delivery, self-healing and cooling devices. However, efficient connections between networks of micro/nanochannels and external fluidic ports are key to successful applications of three-dimensional micro/nanofluidic devices. Therefore, in the current work, the extent of the reservoir geometry’s role in interfacing with vascular (micro/nanochannel) networks and in the… Show more

Three-dimensional (3D) micro/nanofluidic devices can accelerate progress in numerous fields such as tissue engineering, drug delivery, self-healing and cooling devices. However, efficient connections between networks of micro/nanochannels and external fluidic ports are key to successful applications of three-dimensional micro/nanofluidic devices. Therefore, in the current work, the extent of the reservoir geometry’s role in interfacing with vascular (micro/nanochannel) networks and in the enabling of connections with external fluidic ports while maintaining the compactness of devices has been experimentally and theoretically investigated. A statistical modelling suggested that a branch-shaped reservoir demonstrates enhanced interfacing with vascular networks when compared to other regular geometries of reservoirs. Time-lapse dye flow experiments by capillary action through fabricated 3D micro/nanofluidic devices confirmed the connectivity of branch-shaped reservoirs with micro/nanochannel networks in fluidic devices. This demonstrated a ~2.2-fold enhancement of the volumetric flow rate in micro/nanofluidic networks when interfaced to branch-shaped reservoirs over rectangular reservoirs. The enhancement is due to a ~2.8-fold increase in the perimeter of the reservoirs. In addition, the mass transfer experiments exhibited a ~1.7-fold enhancement in solute flux across 3D micro/nanofluidic devices that interfaced with branch-shaped reservoirs when compared to rectangular reservoirs. The fabrication of three-dimensional micro/nanofluidic devices and their efficient interfacing through branch-shaped reservoirs to an external fluidic port can potentially enable their use in complex applications in which enhanced surface-to-volume interactions are desirable. Show less

Polymeric micro-/nano-fibers have potential for a variety of applications e.g. tissue engineering, filter media, biosensors, textiles etc. Many of these applications depend onporosity and pore size distribution of thesemicro-/nano-fiber meshes, that need to be characterized before any application. Therefore, in the current work, we aimed at understanding the interplay of structural and physical
properties of micro-/nanofiber meshes by generating an insilico geometric model of these meshes… Show more

Polymeric micro-/nano-fibers have potential for a variety of applications e.g. tissue engineering, filter media, biosensors, textiles etc. Many of these applications depend onporosity and pore size distribution of thesemicro-/nano-fiber meshes, that need to be characterized before any application. Therefore, in the current work, we aimed at understanding the interplay of structural and physical
properties of micro-/nanofiber meshes by generating an insilico geometric model of these meshes through a novel algorithm. A new algorithm for fiber mesh generation was developed which generated fiber meshes with controlled structural parameters such as fiber diameter, length, alignment, angle of bend and fusion, thereby enabling study of physical properties. Furthermore, the surface mesh model generated by our algorithm may enablecomputational study of mechanical properties, transport phenomenon before landingupon an actual fabrication and application. This will not only save numerous attempt of trial and error method of parameter optimization during fabrication of micro-/nanofibrous materials but also save time, energy and resources. Show less

Cephalometric analysis has long helped researchers and orthodontic practitioners for evaluation of facial growth, understanding facial morphology and its ethnic variations, orthodontic diagnosis and treatment planning for patients presenting with malocclusion and dentofacial deformities. Mostly, inaccuracy in cephalometric measurements is a reflection of errors in identification and accurate localization of anatomical landmarks. The accuracy of landmark identification is greatly influenced by… Show more

Cephalometric analysis has long helped researchers and orthodontic practitioners for evaluation of facial growth, understanding facial morphology and its ethnic variations, orthodontic diagnosis and treatment planning for patients presenting with malocclusion and dentofacial deformities. Mostly, inaccuracy in cephalometric measurements is a reflection of errors in identification and accurate localization of anatomical landmarks. The accuracy of landmark identification is greatly influenced by knowledge of the operator and experience. Moreover, the process of manual detection is tedious and time consuming. Therefore, a need for development of robust and accurate algorithms for automatic detection of landmarks on cephalometric images has been comprehended. In this work, we hereby propose an optimized template matching (OTM) algorithm which could automatically localize hard and soft tissue anatomical landmarks on lateral cephalometric images. This algorithm was tested for sixteen hard and eight soft tissue landmarks chosen in 12 regions on 37 lateral cephalograms obtained from subjects of either sex covering wide spectrum of malocclusion cases. The results of proposed automatic algorithm were compared to that of manual marking conducted by three experienced orthodontic specialists. All the 24 landmarks (100%) were detected within 3.0 mm error range of manual marking, 23 (96%) were detected within 2.5 mm error range and 16 (66.6%) landmarks were detected within 2.0 mm error range. The optimized template matching (OTM) algorithm may prove to be a promising approach in automatic detection of anatomical landmarks on cephalometric images. Show less

Electrospun micro/nanofibrous biomaterials are widely used as extracellular matrix substitutes in tissue engineering applications because of their structural and mechanical properties. To explore the influence of microstructure on the mechanical behavior of fibrous material, a mathematical model of the fiber system was developed. The model describes the microstructural properties of a fibrous matrix using a probability density function, and enables study of their mechanical properties. The… Show more

Electrospun micro/nanofibrous biomaterials are widely used as extracellular matrix substitutes in tissue engineering applications because of their structural and mechanical properties. To explore the influence of microstructure on the mechanical behavior of fibrous material, a mathematical model of the fiber system was developed. The model describes the microstructural properties of a fibrous matrix using a probability density function, and enables study of their mechanical properties. The results from the mathematical model were validated by qualitative comparison with the experimental results of mechanical testing of polystyrene electrospun nanofibrous materials. The analyses show a trend of three-phase load–displacement behavior. Initially, as an increasing number of fibers are recruited for load bearing, the load–displacement curve has a ‘J’-shaped toe region, which is followed by a nearly linear load–displacement curve, in which the number of load-bearing fibers remains nearly steady. Finally, there is a phase when the load–displacement curve descends, indicating failure of the material. The increase in flexibility of the fibrous material makes it stronger, but the randomness of fiber orientation makes the fibrous structure more flexible at the cost of lower strength. The measured mechanical properties of a fibrous matrix were also observed to be dependent on sample size. Therefore, the analyses establish a clear link between the structure and strength of fibrous materials for optimized design and fabrication of fibrous biomaterials with targeted use in tissue engineering, regenerative medicine and drug delivery. The model also establishes a need for standardization of experimental protocols for mechanical characterization of fibrous materials for consistency. Show less

Radiation therapy (RT) is one of the modalities employed for treatment of cancer patients by irradiating the region to be treated using ionizing radiation. In radiation therapy, accurate patient positioning is an important requirement for precise dosage delivery. This paper presents a methodology for image registration employed in verification of the patient's position during radiation therapy for the treatment of cancer patients. Before treatment, portal image of the patient is acquired using… Show more

Radiation therapy (RT) is one of the modalities employed for treatment of cancer patients by irradiating the region to be treated using ionizing radiation. In radiation therapy, accurate patient positioning is an important requirement for precise dosage delivery. This paper presents a methodology for image registration employed in verification of the patient's position during radiation therapy for the treatment of cancer patients. Before treatment, portal image of the patient is acquired using Electronic Portal Imaging Device (EPID) and compared with the Digitally Reconstructed Radiograph (DRR) to evaluate patient set-up error. Our approach involves the use of image registration techniques based on anatomical landmarks prior to the estimation of positional errors between the reference i.e. DRR and portal image. In proposed approach, three pairs of visually recognizable corresponding landmarks were located on DRR and the portal image to extract the transformational parameters required for accurate image registration. The proposed approach was applied on model images to verify the algorithm and results suggested that the proposed approach is promising for image registration before evaluating positional error for radiation therapy. Show less

Manual cephalogram marking has a long way from marking on tracing sheet to the availability of commercial softwares for cephalometric analysis. With the effort involved in manual marking and time consumption, it becomes imperative for modern science to envisage algorithms which could automatically locate landmarks on the cephalogram images and perform the various analysis. In this work, we hereby propose a wavelet transform based feature extraction algorithm for detection of a landmark on… Show more

Manual cephalogram marking has a long way from marking on tracing sheet to the availability of commercial softwares for cephalometric analysis. With the effort involved in manual marking and time consumption, it becomes imperative for modern science to envisage algorithms which could automatically locate landmarks on the cephalogram images and perform the various analysis. In this work, we hereby propose a wavelet transform based feature extraction algorithm for detection of a landmark on cephalogram images. 15 landmarks were detected on the images using wavelet transform and all landmarks were detected within the acceptable accuracy limits. This algorithm may have a promising approach in detection of further anatomical landmarks automatically and analysis and thus may help orthodontic practitioners in better and faster treatment planning. Show less