Dual parametric sensors for highly sensitive nucleic acid detection

The primary focus of this research work was on the design and development of a molecular scale (nano-scale) capacitive sensing mechanism for the highly sensitive and label-free detection of Nucleic Acid hybridization. These novel capacitive sensors with nano-scale electrode spacing offer solutions to many problems suffered by the conventional signal transduction mechanisms, thereby immensely improving the sensitivity of the biomolecular detection processes. Reducing the separation between the capacitive electrodes to the same scale as the Debye length of the sample solution, results in the overlapping of the electrical double layers of the two electrodes, thereby confining them to occupy a major fraction of the dielectric volume. This decreases the potential drop across the electrodes and thus dielectric measurements at low frequencies are made possible. The dielectric properties during hybridization reaction were measured using 10- mer nucleotide sequences. A 30-40% change in relative permittivity (capacitance) was observed due to DNA hybridization at 10Hz, which is much more sensitive than the previously reposted detection measurements (2-8% signal change). In parallel to the above work, a second label-free sensing mechanism based on field effect capacitive sensors with Metal-Oxide-Semiconductor (MOS) structure has been developed and its ability to provide real-time monitoring of oligonucleotide immobilization and hybridization events are studied. The immobilization of probe oligomers on the sensor surface and their hybridization with the target oligomers of complimentary sequences has produced significant shifts (140mV and 73mV respectively) in the Capacitance-Voltage characteristics measured across the device. In an attempt to utilize the individual merits of the nano-scale electrochemical capacitive sensor and the field effect MOS capacitive structure, a novel dual parametric sensing architecture comprising of both these transducing elements on a single sensor is designed. The detection scheme based on the combined analysis of the two parameters- Dielectric property and intrinsic molecular charge- of Nucleic acid molecules has found to reveal complimentary information of significance about the analyte-probe interactions. As a separate experiment the applications and promises of a novel technique of enhancing the speed and selectivity of the molecular detection processes by the application of an external electric field of precisely controlled intensity was studied. Experiments were conducted with 10-mer sequences and proved the feasibility of this technique in inducing in providing a faster and selective immobilization and hybridization reactions. The research work in this direction has been in collaboration with the Rational Affinity Devices, LLC, a New Jersey based corporation. The above mentioned biosensing mechanisms and detection techniques have the advantage of simplifying the readout and increasing the speed and ease of nucleic acid assays, which is especially desirable for characterizing infectious agents, scoring sequence polymorphism and genotypes, and measuring mRNA or miRNA levels during expression profiling. Once fully optimized and well assembled they have great potential to be developed in to a commercial full-scale biosensor capable of providing high-value diagnostic testing at the point of patient care places

A 3D-printed hybrid nasal cartilage with functional electronic olfaction

Advances in biomanufacturing techniques have opened the doors to recapitulate human sensory organs such as the nose and ear in vitro with adequate levels of functionality. Such advancements have enabled simultaneous targeting of two challenges in engineered sensory organs, especially the nose: i) mechanically robust reconstruction of the nasal cartilage with high precision and ii) replication of the nose functionality: odor perception. Hybrid nasal organs can be equipped with remarkable capabilities such as augmented olfactory perception. Herein, a proof-of-concept for an odor-perceptive nose-like hybrid, which is composed of a mechanically robust cartilage-like construct and a biocompatible biosensing platform, is proposed. Specifically, 3D cartilage-like tissue constructs are created by multi-material 3D bioprinting using mechanically tunable chondrocyte-laden bioinks. In addition, by optimizing the composition of stiff and soft bioinks in macro-scale printed constructs, the competence of this system in providing improved viability and recapitulation of chondrocyte cell behavior in mechanically robust 3D constructs is demonstrated. Furthermore, the engineered cartilage-like tissue construct is integrated with an electrochemical biosensing system to bring functional olfactory sensations toward multiple specific airway disease biomarkers, explosives, and toxins under biocompatible conditions. Proposed hybrid constructs can lay the groundwork for functional bionic interfaces and humanoid cyborgs7

3D printing is a transformative technology in congenital heart disease

Survival in congenital heart disease has steadily improved since 1938, when Dr. Robert Gross successfully ligated for the first time a patent ductus arteriosus in a 7-year-old child. To continue the gains made over the past 80 years, transformative changes with broad impact are needed in management of congenital heart disease. Three-dimensional printing is an emerging technology that is fundamentally affecting patient care, research, trainee education, and interactions among medical teams, patients, and caregivers. This paper first reviews key clinical cases where the technology has affected patient care. It then discusses 3-dimensional printing in trainee education. Thereafter, the role of this technology in communication with multidisciplinary teams, patients, and caregivers is described. Finally, the paper reviews translational technologies on the horizon that promise to take this nascent field even further

Wearable bio and chemical sensors

Chemical and biochemical sensors have experienced tremendous growth in the past decade due to advances in material chemistry combined with the emergence of digital communication technologies and wireless sensor networks (WSNs) [1]. The emergence of wearable chemical and biochemical sensors is a relatively new concept that poses unique challenges to the field of wearable sensing. This is because chemical sensors have a more complex mode of operation, compared to physical transducers, in that they must interact in some manner with specific molecular targets in the sample medium. To understand the challenges in developing wearable chemical and biochemical sensors the traits of these devices will be discussed in this introductory section. Following this the potential parameters of interest are presented and examples of wearable systems are discussed. A range of sampling techniques and methods of chemical sensing are presented along with integration issues and design challenges. Finally, some of the main application areas of this novel technology are discussed

A new photocrosslinkable polycaprolactone based ink for three dimensional inkjet printing

A new type of photocrosslinkable polycaprolactone (PCL)-based ink that is suitable for three-dimensional (3D) inkjet printing has been developed. Photocrosslinkable PCL dimethylacrylate was synthesized and mixed with poly(ethylene glycol) diacrylate to prepare an ink with a suitable viscosity for inkjet printing. The ink performance under different printing environments, initiator concentrations, and postprocess was studied. This showed that a nitrogen atmosphere during printing was beneficial for curing and material property optimization, as well as improving the quality of structures produced. A simple structure, building in the z-direction, demonstrated the potential for thismaterial for the production of 3D printed objects. Cells’ testwas carried out to investigate the biocompatibility of the developed ink

3D inkjet-printed UV-curable inks for multi-functional electromagnetic applications

Inkjet printing of multiple materials is usually processed in multiple steps due to various jetting and curing/sintering conditions. In this paper we report on the development of all inkjet-printed UV-curable electromagnetic responsive inks in a single process, and the electromagnetic characterization of the developed structure. The ink consists of iron oxide (Fe3O4) nanoparticles (nominal particle size 50–100 nm) suspended within a UV curable matrix resin. The viscosity and surface tension of the inks were tuned to sit within the inkjet printability range. Multiple layers of the electromagnetic active ink were printed alongside passive UV-curable ink in a single manufacturing process to form a multi-material waffle shape. The real permittivity of the cured passive ink, active ink and waffle structure at a frequency of 8–12 GHz were 2.25, 2.73 and 2.65 F/m, respectively. This shows the potential of additive manufacturing (AM) to form multi-material structures with tunable electromagnetic properties

Genomics, social media and mobile phone data enable mapping of SARS-CoV-2 lineages to inform health policy in Bangladesh.

Genomics, combined with population mobility data, used to map importation and spatial spread of SARS-CoV-2 in high-income countries has enabled the implementation of local control measures. Here, to track the spread of SARS-CoV-2 lineages in Bangladesh at the national level, we analysed outbreak trajectory and variant emergence using genomics, Facebook 'Data for Good' and data from three mobile phone operators. We sequenced the complete genomes of 67 SARS-CoV-2 samples (collected by the IEDCR in Bangladesh between March and July 2020) and combined these data with 324 publicly available Global Initiative on Sharing All Influenza Data (GISAID) SARS-CoV-2 genomes from Bangladesh at that time. We found that most (85%) of the sequenced isolates were Pango lineage B.1.1.25 (58%), B.1.1 (19%) or B.1.36 (8%) in early-mid 2020. Bayesian time-scaled phylogenetic analysis predicted that SARS-CoV-2 first emerged during mid-February in Bangladesh, from abroad, with the first case of coronavirus disease 2019 (COVID-19) reported on 8 March 2020. At the end of March 2020, three discrete lineages expanded and spread clonally across Bangladesh. The shifting pattern of viral diversity in Bangladesh, combined with the mobility data, revealed that the mass migration of people from cities to rural areas at the end of March, followed by frequent travel between Dhaka (the capital of Bangladesh) and the rest of the country, disseminated three dominant viral lineages. Further analysis of an additional 85 genomes (November 2020 to April 2021) found that importation of variant of concern Beta (B.1.351) had occurred and that Beta had become dominant in Dhaka. Our interpretation that population mobility out of Dhaka, and travel from urban hotspots to rural areas, disseminated lineages in Bangladesh in the first wave continues to inform government policies to control national case numbers by limiting within-country travel

3D inkjet printing of electronics using UV conversion

The production of electronic circuits and devices is limited by current manufacturing methods that limit both the form and potentially the performance of these systems. Additive Manufacturing (AM) is a technology that has been shown to provide cross sectoral manufacturing industries with significant geometrical freedom. A research domain known as Multi-Functional Additive Manufacturing (MFAM) in its infancy looks to couple the positive attributes of AM with application in the electronics sector could have a significant impact on the development of new products, however there are significant hurdles to overcome. This paper reports on the single step MFAM of three dimensional (3D) electronic circuitry within a polymeric structure using a combination of conductive and non-conductive materials within a single material jetting based AM system. The basis of this breakthrough is a study of the optical absorption regions of a silver nanoparticle (AgNP) conductive ink which lead to a novel method to rapidly process and sinter silver nanoparticle inks in ambient conditions using simple UV radiation contemporaneously with UV-curing of deposited polymeric structures

Wearable smart sensor systems integrated on soft contact lenses for wireless ocular diagnostics

Wearable contact lenses which can monitor physiological parameters have attracted substantial interests due to the capability of direct detection of biomarkers contained in body fluids. However, previously reported contact lens sensors can only monitor a single analyte at a time. Furthermore, such ocular contact lenses generally obstruct the field of vision of the subject. Here, we developed a multifunctional contact lens sensor that alleviates some of these limitations since it was developed on an actual ocular contact lens. It was also designed to monitor glucose within tears, as well as intraocular pressure using the resistance and capacitance of the electronic device. Furthermore, in-vivo and in-vitro tests using a live rabbit and bovine eyeball demonstrated its reliable operation. Our developed contact lens sensor can measure the glucose level in tear fluid and intraocular pressure simultaneously but yet independently based on different electrical responses.ope