A comprehensive review on 3D tissue models: Biofabrication technologies and preclinical applications

The limitations of traditional two-dimensional (2D) cultures and animal testing, when it comes to precisely foreseeing the toxicity and clinical effectiveness of potential drug candidates, have resulted in a notable increase in the rate of failure during the process of drug discovery and development. Three-dimensional (3D) in-vitro models have arisen as substitute platforms with the capacity to accurately depict in-vivo conditions and increasing the predictivity of clinical effects and toxicity of drug candidates. It has been found that 3D models can accurately represent complex tissue structure of human body and can be used for a wide range of disease modeling purposes. Recently, substantial progress in biomedicine, materials and engineering have been made to fabricate various 3D in-vitro models, which have been exhibited better disease progression predictivity and drug effects than convention models, suggesting a promising direction in pharmaceutics. This comprehensive review highlights the recent developments in 3D in-vitro tissue models for preclinical applications including drug screening and disease modeling targeting multiple organs and tissues, like liver, bone, gastrointestinal tract, kidney, heart, brain, and cartilage. We discuss current strategies for fabricating 3D models for specific organs with their strengths and pitfalls. We expand future considerations for establishing a physiologically-relevant microenvironment for growing 3D models and also provide readers with a perspective on intellectual property, industry, and regulatory landscape.

Nested Biofabrication: Matryoshka-Inspired Intra-Embedded Bioprinting

Engineering functional tissues and organs remains a fundamental pursuit in bio-fabrication. However, the accurate constitution of complex shapes and internal anatomical features of specific organs, including their intricate blood vessels and nerves, remains a significant challenge. Inspired by the Matryoshka doll, here a new method called "Intra-Embedded Bioprinting (IEB)" is introduced building upon existing embedded bioprinting methods. a xanthan gum-based material is used which served a dual role as both a bioprintable ink and a support bath, due to its unique shear-thinning and self-healing properties. IEB's capabilities in organ modeling, creating a miniaturized replica of a pancreas using a photocrosslinkable silicone composite is demonstrated. Further, a head phantom and a Matryoshka doll are 3D printed, exemplifying IEB's capability to manufacture intricate, nested structures. Toward the use case of IEB and employing an innovative coupling strategy between extrusion-based and aspiration-assisted bioprinting, a breast tumor model that included a central channel mimicking a blood vessel, with tumor spheroids bioprinted in proximity is developed. Validation using a clinically-available chemotherapeutic drug illustrated its efficacy in reducing the tumor volume via perfusion over time. This method opens a new way of bioprinting enabling the creation of complex-shaped organs with internal anatomical features.

Nested biofabrication: Matryoshka-inspired Intra-embedded Bioprinting

Engineering functional tissues and organs remains a fundamental pursuit in biofabrication. However, the accurate constitution of complex shapes and internal anatomical features of specific organs, including their intricate blood vessels and nerves, remains a significant challenge. Inspired by the Matryoshka doll, we here introduce a new method called 'Intra-Embedded Bioprinting (IEB),' building upon existing embedded bioprinting methods. We used a xanthan gum-based material, which served a dual role as both a bioprintable ink and a support bath, due to its unique shear-thinning and self-healing properties. We demonstrated IEB's capabilities in organ modelling, creating a miniaturized replica of a pancreas using a photocrosslinkable silicone composite. Further, a head phantom and a Matryoshka doll were 3D printed, exemplifying IEB's capability to manufacture intricate, nested structures. Towards the use case of IEB and employing innovative coupling strategy between extrusion-based and aspiration-assisted bioprinting, we developed a breast tumor model that included a central channel mimicking a blood vessel, with tumor spheroids bioprinted in proximity. Validation using a clinically-available chemotherapeutic drug illustrated its efficacy in reducing the tumor volume via perfusion over time. This method opens a new way of bioprinting enabling the creation of complex-shaped organs with internal anatomical features.

A Versatile Photocrosslinkable Silicone Composite for 3D Printing Applications

Embedded printing has emerged as a valuable tool for fabricating complex structures and microfluidic devices. Currently, an ample of amount of research is going on to develop new materials to advance its capabilities and increase its potential applications. Here, we demonstrate a novel, transparent, 3D printable, photocrosslinkable, and tuneable silicone composite that can be utilized as a support bath or an extrudable ink for embedded printing. The proposed silicone composite can be tuned to achieve ideal rheological properties, such as optimal self-recovery and yield stress, for use in 3D printing. When used as a support bath, it facilitated the generation microfluidic devices with circular channels of diameter up to 30 µm. To demonstrate its utility, flow focusing microfluidic devices were fabricated for generation of Janus microrods, which can be easily modified for multitude of applications. When used as an extrudable ink, 3D printing of complex-shaped micro- and macro-constructs were achieved with integrated electronics, which greatly extends its potential applications towards developing complex flexible parts for soft robotics and prosthetics. Further, its biocompatibility was tested with multiple cell types to validate its applicability for medical and tissue engineering use. Altogether, this material offers a myriad of potential applications in material and medical fields by providing a facile approach to develop complicated 3D structures and interconnected channels that can further advance microfluidics and soft-robotics research.

High-throughput microgel biofabrication via air-assisted co-axial jetting for cell encapsulation, 3D bioprinting and scaffolding applications

Microgels have recently received widespread attention for their applications in a wide array of domains such as tissue engineering, regenerative medicine, and cell and tissue transplantation because of their properties like injectability, modularity, porosity, and the ability to be customized in terms of size, form, and mechanical properties. However, it is still challenging to mass (high-throughput) produce microgels with diverse sizes and tunable properties. Herein, we utilized an air-assisted co-axial device (ACAD) for continuous production of microgels in a high-throughput manner. To test its robustness, microgels of multiple hydrogels and their combination, including alginate (Alg), gelatin methacrylate (GelMA) and Alg-GelMA, were formed at a maximum production rate of ~65,000 microgels per sec while retaining circularity and a size range of 50-500 µm based on varying air pressure levels. The ACAD platform allowed single and multiple cell encapsulation with 74±6% efficiency. These microgels illustrated appealing rheological properties such as yield stress, viscosity, and shear modulus for bioprinting applications. Specifically, Alg microgels have the potential to be used as a sacrificial support bath while GelMA microgels have potential for direct extrusion both on their own or when loaded in a bulk GelMA hydrogel. Generated microgels showed high cell viability (>90%) and proliferation of MDA-MB-231 and human dermal fibroblasts over seven days in both encapsulation and scaffolding applications, particularly for GelMA microgels. The developed strategy provides a facile and rapid approach without any complex or expensive consumables and accessories for scalable high-throughput microgel production for cell therapy, tissue regeneration and 3D bioprinting applications.

A study of road rage in India

Introduction

Road rage is a term used to describe driving usually extreme in nature. There seems to be a multifactorial relationship between the situational characteristics of an anger provoking road situation and the feelings of anger and road behaviour.

Objectives

To examine driver anger with regards to various sociodemographic parameter.

Methods

282 participants completed an internet-based survey including sociodemographic profile, anger assessment while driving using the Deffenbacher Driver Anger Scale, details of the driving. Participants were recruited through networks of authors, institution. The survey was disseminated through social media applications and email by snowball sampling method.

Results

Mean age of the sample was 26.1 years with age group 24-29 years making half of the population. Majority sample were males (62.1%), graduates (53.2%), professionals (45.7%), urban locality based, nuclear family type. People experienced greater anger on Defenbacher likert scale for the following situations, when Someone is driving very close to your rear bumper (mean= 3.09), Someone cuts in right in front of you on the motorway(mean= 3.44), Someone cuts in and takes the parking spot(mean= 3.19), Someone coming towards you does not dim headlights at night(mean= 3.26), driving behind a vehicle smoking badly or giving off fumes(mean= 3.38).

Conclusions

The results revealed a prevalence of high anger scores amongst Indian drivers. The rage didn’t vary significantly within gender, locality, type of vehicle, however the anger scores were significantly higher in younger population. Strategies targeting at driving safety and reducing road rage should be implemented by authorities with sensitization of the drivers.

Disclosure

No significant relationships.

Elektra complex in dissociative identity disorder: A case report

Introduction

Dissociative identity disorder is a quite popular psychiatric diagnosis in general public but in actuality has a very low prevalence rate. Dissociative identity disorders are characterized by disruption of identity characterized by two or more distinct personality states with its own memories, behaviour, and preferences.

Objectives

Authors present a case report about a patient of Dissociative identity disorder with Elektra complex as unconscious conflict.

Methods

A case report along with literature review forms the basis of discussion.

Results

Mrs A, 30 years female, a housewife, belonging to low socioeconomic status, reported to the OPD, along with her husband. About 1 year ago her family members noticed that her behaviour and action became altered. Such alteration in behaviour was only episodic. A detailed evaluation was done and a diagnosis of Dissociative identity disorder was established. The treatment included psychotherapy facilitated by hypnosis addressing the conflict along with escitalopram 10 mg once a day and clonazepam 0.5mg at night, clonazepam was tapered and stopped within 1 month while escitalopram was hiked upto 20 mg and patient improved along with decrease DES scores.

Conclusions

In Freudian psychology the girl child identifies with her mother and represses her sexual feelings toward her father commonly known as the Elektra complex. In spite of trance and possession syndrome being more prevalent in countries like India, we urge to keep dissociative identity disorder as a differential in order to catch the eye of the clinicians and researchers on the recognition of clinical manifestation and exploration of therapeutic strategies.

Disclosure

No significant relationships.

A report of use of baclofen in intractable hiccups

Introduction

Hiccups are an involuntarily powerful spasm of the diaphragm, followed by a sudden inspiration with a closure of the glottis. Hiccups lasting longer than one month is termed intractable hiccups. Intractable hiccups can be caused by structural or functional disturbances of the medulla, afferent or efferent nerves to the respiratory muscles or metabolic and endocrine disorders, drugs, general anaesthesia and emotional problems.

Objectives

Authors present a case report about curing a patient of intractable hiccups using baclofen along with literature review.

Methods

A case report along with literature review forms the basis of discussion.

Results

A 30-year female diagnosed with schizophrenia stable on 2mg risperidone for 3 years presented to the outpatient department with complain of intractable hiccups for 6 months. Frequency of hiccups was around 10-12 times per minute and continued throughout the day leading to significant socio-occupational distress. patient had been receiving medical treatment for last 4 months for the same including Metoclopramide, chlorpromazine along with trying breath holding and drinking cold water but symptoms persisted. Her ECG, chest X-ray, complete blood counts were unremarkable, CT scan of brain was normal. Patient was started on baclofen 10mg thrice daily. Within 1-week patient had dramatic response and complete remission was achieved in 2 weeks.

Conclusions

Beclofen is effective in hiccups because it is an analogue of GABA, that decreases excitability and inhibits the hiccup reflex, which reduces synaptic transmission. Baclofen is used to treat hiccups, and can be used either as a first-line treatment or if patient does not respond to other medications.

Disclosure

No significant relationships.

BA3338, a surface layer homology domain possessing protein augments immune response and protection efficacy of protective antigen against Bacillus anthracis in mouse model

AIM

Category A classified Bacillus anthracis is highly fatal pathogen that causes anthrax and creates challenges for global security and public health. In this study, development of a safe and ideal next-generation subunit anthrax vaccine has been evaluated in mouse model.

METHOD AND RESULTS

Protective antigen (PA) and BA3338, a surface layer homology (SLH) domain possessing protein were cloned, expressed in heterologous system and purified by IMAC. Recombinant PA and BA3338 with alum were administered in mouse alone or in combination. The humoral and cell-mediated immune response was measured by ELISA and vaccinated animals were challenged with B. anthracis spores via intraperitoneal route. The circulating IgG antibody titre of anti-PA and anti-BA3338 was found significantly high in the first and second booster sera. A significant enhanced level of IL-4, IFN-γ and IL-12 was observed in antigens stimulated supernatant of splenocytes of PA + BA3338 vaccinated animals. A combination of PA and BA3338 provided 80% protection against 20 LD₅₀ lethal dose of B. anthracis spores.

CONCLUSION

Both antigens induced admirable humoral and cellular immune response as well as protective efficacy against B. anthracis spores.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study has been evaluated for the first time using BA3338 as a vaccine candidate alone or in combination with well-known anthrax vaccine candidate PA. The findings of this study demonstrated that BA3338 could be a co-vaccine candidate for development of dual subunit vaccine against anthrax.

Rapid laser solver for the phase retrieval problem

Tailored physical systems were recently exploited to rapidly solve hard computational challenges, such as spin simulators, combinatorial optimization, and focusing through scattering media. Here, we address the phase retrieval problem where an object is reconstructed from its scattered intensity distribution. This is a key problem in many applications, ranging from x-ray imaging to astrophysics, and currently, it lacks efficient direct reconstruction methods: The widely used indirect iterative algorithms are inherently slow. We present an optical approach based on a digital degenerate cavity laser, whose most probable lasing mode rapidly and efficiently reconstructs the object. Our experimental results suggest that the gain competition between the many lasing modes acts as a highly parallel computer that could rapidly solve the phase retrieval problem. Our approach applies to most two-dimensional objects with known compact support, including complex-valued objects, and can be generalized to imaging through scattering media and other hard computational tasks.

A Rapid Flow through Membrane Enzyme Linked Immunosorbent Assay for Bacillus anthracis using Surface Array Protein as a Biomarker

Anthrax, caused by Bacillus anthracis is an important disease of biowarfare and public health importance. It is imperative to develop a simple system which can detect and differentiate B. anthracis from other closely related species. The surface array protein (Sap), which is secreted during the early growth phase of bacteria can be an important biomarker for detection of B. anthracis. In the present study, we have developed a rapid flow through membrane ELISA for detection of B. anthracis. Polyclonal antibodies were used to develop a sandwich plate ELISA, which could detect 3.9 ng/ml of recombinant Sap. B. anthracis bacteria grown in culture broth could be detected after 5 h of growth. Finally, a rapid flow through membrane ELISA was developed which can be accomplished just within 2 minutes, instead of 3-4 h as required in sandwich plate ELISA. The results established that the developed flow through membrane ELISA may be used for detection of B. anthracis. The proposed method is rapid, safe and user friendly for detection of B. anthracis culture.

Enhanced production and purification of recombinant surface array protein (Sap) for use in detection of Bacillus anthracis

Surface array protein (Sap) can be an important biomarker for specific detection of Bacillus anthracis, which is released by the bacterium during its growth in culture broth. In the present work, we have cloned and expressed Sap in Escherichia coli. The culture conditions and cultivation media were optimized and used in batch fermentation process for scale up of Sap in soluble form. The recombinant Sap was purified employing affinity chromatography followed by diafiltration. The final yield of purified protein was 20 and 46 mg/l of culture during shake flasks and batch fermentation, respectively. The protein purity and its reactivity were confirmed employing SDS-PAGE and Western blot, respectively. The antibodies raised against purified Sap were evaluated by Western blotting for detection of Sap released by B. anthracis. Our results showed that the Sap could be a novel marker for detection and confirmation of B. anthracis.

Photo-responsive liquid crystals derived from azobenzene centered cholesterol-based tetramers

Azobenzene centered cholesterol based tetramers showing spherulitic domains and photoresponsive behaviour in solution as well as Langmuir monolayers.

Development of a real-time loop-mediated isothermal amplification assay for detection of Burkholderia mallei

Burkholderia mallei is the aetiological agent of glanders, a highly contagious and re-emerging zoonotic disease. Early diagnosis of glanders is critically important to ensure timely treatment with appropriate antibiotics in humans, and to prevent spread of infection in animals. Molecular detection of B. mallei has always been troublesome because of its genetic similarity with Burkholderia pseudomallei, the causative agent of melioidosis. In present investigation, a set of six B. mallei-specific primers were designed and a simple, rapid, specific and sensitive real-time loop-mediated isothermal amplification (LAMP) assay was developed for detection of B. mallei. The LAMP assay could detect as low as 1 pg of B. mallei genomic DNA and 5.5 × 10³  CFU/ml of B. mallei in spiked human blood. The assay was highly specific for B. mallei as it did not cross-react with other bacterial strains used in the study. The established LAMP assay is field adaptable and can be a better and viable alternative to PCR-based techniques for detection of B. mallei in glanders endemic areas with resource-limited settings.

Intensity noise correlations in a two-frequency VECSEL

We present an experimental and theoretical study of the intensity noise correlation between the two orthogonally polarized modes in a dual frequency Vertical External Cavity Surface Emitting Laser (VECSEL). The dependence of the noise correlation spectra on the non-linear coupling between the two orthogonally polarized modes is put into evidence. Our results show that for small coupling the noise correlation amplitude and phase spectra remain nearly flat (around -6 dB and 0° respectively) within the frequency range of our interest (from 100 kHz to 100 MHz). But for higher values of the coupling constant the low frequency behaviors (below 1-2 MHz) of the correlation amplitude and phase spectra are drastically changed, whereas above this cut-off frequency (1-2 MHz) the correlation spectra are almost independent of coupling strength. The theoretical model is based on the assumptions that the only source of noise in the frequency range of our interest for the two modes are pump noises, which are white noises of equal amplitude but partially correlated.

Surface Plasmon Resonance Biosensor for Detection of Bacillus anthracis, the Causative Agent of Anthrax from Soil Samples Targeting Protective Antigen

Bacillus anthracis, the causative agent of anthrax is one of the most important biological warfare agents. In this study, surface plasmon resonance (SPR) technology was used for indirect detection of B. anthracis by detecting protective antigen (PA), a common toxin produced by all live B. anthracis bacteria. For development of biosensor, a monoclonal antibody raised against B. anthracis PA was immobilized on carboxymethyldextran modified gold chip and its interaction with PA was characterized in situ by SPR and electrochemical impedance spectroscopy. By using kinetic evaluation software, KD (equilibrium constant) and Bmax (maximum binding capacity of analyte) were found to be 20 fM and 18.74, respectively. The change in Gibb's free energy (∆G = -78.04 kJ/mol) confirmed the spontaneous interaction between antigen and antibody. The assay could detect 12 fM purified PA. When anthrax spores spiked soil samples were enriched, PA produced in the sample containing even a single spore of B. anthracis could be detected by SPR. PA being produced only by the vegetative cells of B. anthracis, confirms indirectly the presence of B. anthracis in the samples. The proposed method can be a very useful tool for screening and confirmation of anthrax suspected environmental samples during a bio-warfare like situation.

Observation of noise phase locking in a single-frequency VECSEL

We present an experimental observation of phase locking effects in the intensity noise spectrum of a semiconductor laser. These noise correlations are created in the medium by coherent carrier-population oscillations induced by the beatnote between the lasing and non-lasing modes of the laser. This phase locking leads to a modification of the intensity noise profile at around the cavity free-spectral-range value. The noise correlations are evidenced by varying the relative phase shift between the laser mode and the non-lasing adjacent side modes.

Measurement of the coupling constant in a two-frequency VECSEL

We measure the coupling constant between the two perpendicularly polarized eigenstates of a two-frequency Vertical External Cavity Surface Emitting Laser (VECSEL). This measurement is performed for different values of the transverse spatial separation between the two perpendicularly polarized modes. The consequences of these measurements on the two-frequency operation of such class-A semiconductor lasers are discussed.

Supratarsal injection of corticosteroids in the treatment of refractory vernal keratoconjunctivitis

PURPOSE

To study and compare the efficacy of supratarsal injection of dexamethasone sodium phosphate, triamcinolone acetonide and hydrocortisone sodium succinate in treating refractory vernal keratoconjunctivitis (VKC).

METHODS

Prospective randomized, double-masked, case control trial, including 90 eyes of 45 patients with refractory VKC. Both eyes of each patient were randomly assigned to receive supratarsal injection of one of three compounds under study: dexamethasone sodium phosphate (2 mg), triamcinolone acetonide (10.5 mg), and hydrocortisone sodium succinate (50 mg).

RESULTS

All the three drugs were equally effective with no statistically significant difference in the time of resolution of cobblestone papillae, lid oedema, conjunctival discharge and chemosis, Tranta's dots and shield ulcers. There was no statistically significant difference in the severity and rate of recurrence of disease following supratarsal injection of all the three drugs. But recurrence of disease to same severity was seen within 6 months of injection in all cases irrespective of compounds used.

CONCLUSION

Supratarsal injection of corticosteroids is very effective for temporary suppression of severe inflammation associated with VKC.

External fixation in unstable intertrochanteric fractures of femur

Forty elderly patients aged 50-94 years old with unstable intertrochanteric fractures were treated by external fixation at The Central Institute of Orthopaedics, Safdarjang Hospital, New Delhi, India from June 1993 to January 1995. Fracture union was achieved by an average time of 14 weeks in all the patients. Postoperative varus was increased in nine and deep pin-track infection was found in three cases. External fixation minimizes surgical damage and blood loss, and has an added advantage of early mobilization. This technique is simple, safe and economical. It is effective wherever early elective surgery is not possible due to limited resources. It is the method of choice for high-risk geriatric patients.

Dental caries and periodontal disease in Fiji

A national oral survey was conducted in Fiji in 1985/86. The results showed that the prevalence of caries was generally low and most commonly affected pit and fissure surfaces. Comparisons with previous surveys in 1948 and 1965 showed that the prevalence had fallen in primary teeth but remained relatively constant in permanent teeth. There were significant variations in prevalence between residential locations but not between ethnic groups. Periodontal disease was found to be a major public health problem. Except for the percentage of young children with caries-free dentitions, the current status of oral health in Fiji was generally better than that proposed in the WHO goals for the year 2000. The training of dental hygienists to help in the prevention of both dental caries and periodontal disease is discussed.

Surgical treatment of bronchial carcinoid tumours. Radical surgery-prognosis

111 patients (59 male and 52 female) operated on for bronchial carcinoid are reviewed. Their average age was 48 years. 21 bronchoplastic procedures and 16 wedge-resections were performed. All of these patients are alive and no recurrences have been observed. In our experience the usual oncological criteria fail to give unanimous information for prognosis. Conservative resections such as bronchoplastic procedures and wedge- or segmental resections are to be encouraged under strict conditions because of excellent results. The 5-year survival of 52 resected patients amounted to 94.2%.