Needleless vaccine delivery using micro-shock waves

Optothermal Needle-Free Injection of Vaterite Nanocapsules

The propulsion and acceleration of nanoparticles with light have both fundamental and applied significance across many disciplines. Needle-free injection of biomedical nano cargoes into living tissues is among the examples. Here a new physical mechanism of laser-induced particle acceleration is explored, based on abnormal optothermal expansion of mesoporous vaterite cargoes. Vaterite nanoparticles, a metastable form of calcium carbonate, are placed on a substrate, underneath a target phantom, and accelerated toward it with the aid of a short femtosecond laser pulse. Light absorption followed by picosecond-scale thermal expansion is shown to elevate the particle's center of mass thus causing acceleration. It is shown that a 2 µm size vaterite particle, being illuminated with 0.5 W average power 100 fsec IR laser, is capable to overcome van der Waals attraction and acquire 15m sec-1 velocity. The demonstrated optothermal laser-driven needle-free injection into a phantom layer and Xenopus oocyte in vitro promotes the further development of light-responsive nanocapsules, which can be equipped with additional optical and biomedical functions for delivery, monitoring, and controllable biomedical dosage to name a few.

Shockwave versus ultrasound therapy in the enhancement of Aloe vera in cutaneous wound healing

OBJECTIVE

To investigate the healing efficacy of topical Aloe vera enhanced by shockwave or ultrasound therapy on wounds in rats and compare both effects.

METHOD

A total of 75 male albino rats were randomly divided into equal groups A, B, C, D and E. Under anaesthesia, a wound (6cm2) was created on the back of each rat. Group A received topical Aloe vera under occlusive dressing followed by shockwave therapy with the following parameters: 600 shocks, four pulses/second and 0.11mJ/mm2. Group B received topical Aloe vera under occlusive dressing followed by therapeutic ultrasound with the following parameters: pulsed mode, 2:8 duty cycle, 1MHz and 0.5 W/cm2. Group C received the same treatment as group A but in a reversed sequence-the shockwave therapy followed by the Aloe vera gel. Group D received the same treatment as group B but in a reversed sequence-therapeutic ultrasound followed by the Aloe vera gel. And control group E only received topical Aloe vera under occlusive dressing. Each group received three sessions per week, for two weeks. Wound extent and shrinkage rates were measured at study initiation and at the end of each week.

RESULTS

There were significant wound reductions in groups A and B compared to C and D, respectively, and in group A compared to group B.

CONCLUSION

Shockwaves and ultrasound were found to amplify the effect of the Aloe vera on the wound, and there was improved wound healing in the shockwave group A compared to the ultrasound group B.

Hypersonic flow study in a pneumatically operated academic shock tunnel

A hypersonic shock tunnel is a primary tool used for basic experimental research and may be used in engineering and university courses to study compressible flows involving shock waves. In the present study, a pneumatically operated shock tunnel is demonstrated for hypersonic flow studies. The high-pressure nitrogen gas is used to drive a pneumatic cylinder, which is used to burst the thin metal diaphragms. Tunnel-free stream conditions are quantified using the measured pressure values and by applying shock tube relations. The free-stream Mach number of 5.5-7.2 is achieved by varying the bursting pressure and test gas pressure from 2.1 to 4.5 bars and 0.2 to 0.5 bar, respectively. The simulation is performed and the shock standoff distance quantified, and the stagnation pressures measured. The results demonstrate that the pneumatically operated tunnel enhanced operation capacity compared to the manually operated tunnel and well suits the academic hypersonic research and developmental activities.

A microexplosive shockwave-based drug delivery microsystem for treating hard-to-reach areas in the human body

Implantable drug-delivery microsystems have the capacity to locally meet therapeutic requirements by maximizing local drug efficacy and minimizing potential side effects. The internal organs of the human body including the esophagus, gastrointestinal tract, and respiratory tract, with anfractuos contours, all manifest with endoluminal lesions often located in a curved or zigzag area. The ability of localized drug delivery for these organs using existing therapeutic modalities is limited. Spraying a drug onto these areas and using the adhesion and water absorption properties of the drug powder to attach to lesion areas can provide effective treatment. This study aimed to report the development and application of microsystems based on microshockwave delivery of drugs. The devices comprised a warhead-like shell with a powder placed at the head of the device and a flexible rod that could be inserted at the tail. These devices had the capacity to deposit drugs on mucous membranes in curved or zigzag areas of organs in the body. The explosive impact characteristics of the device during drug delivery were analyzed by numerical simulation. In the experiment of drug delivery in pig intestines, we described the biosafety and drug delivery capacity of the system. We anticipate that such microsystems could be applied to a range of endoluminal diseases in curved or zigzag regions of the human body while maximizing the on-target effects of drugs.

Laser-induced cavitation bubbles and shock waves in water near a concave surface

The interplay among the cavitation structures and the shock waves following a nanosecond laser breakdown in water in the vicinity of a concave surface was visualized with high-speed shadowgraphy and schlieren cinematography. Unlike the generation of the main cavitation bubble near a flat or a convex surface, the concave surface refocuses the emitted shock waves and causes secondary cavitation near the acoustic focus which is most pronounced when triggered by the shock wave released during the first main bubble collapse. The shock wave propagation, reflection from the concave surface and its scattering on the dominant cavity is clearly resolvable on the shadowgraphs. The schlieren approach revealed the pressure build up in the last stage of the collapse and the first stage of the rebound. A persistent low-density watermark is left behind the first collapse. The observed effects are important wherever cavities collapse near indented surfaces, such as in cavitation peening, cavitation erosion and ophthalmology.

Needleless or Noninvasive Delivery Technology

Injections of drugs or vaccines have become an indispensable part of living systems. Introduction to injections begins from the vaccination regimen at the neonatal stage and continues throughout the life span of an individual. Conventionally, injections are administered using hypodermic needles and syringes. These usually inject the liquid in the muscle, thus making intramuscular injections the most common form of administration. Although hypodermic syringes have been a clinician's tool in global vaccination efforts, they also have a set of undesirable characteristics. Pathogen transmission in case of HIV and HBV is one of the deadliest disadvantages of the needle-based injection system. Generation of plastic wastes in clinics, needlestick injury, and most importantly, pain associated with needle-based injections are a few more reasons of concern. In light of these issues, developing needle-free injection systems has excited researchers across the globe since the 1950s. Significant advancement has been reported in this field and various needle-free injection systems have been developed and are in clinical practice. This article briefly describes the history of needle-free injection systems and provides a detailed account of a few well-known methods of needle-less injections available.

Shock wave impact on the viability of MDA-MB-231 cells

Shock waves are gaining interests in biological and medical applications. In this work, we investigated the mechanical characteristics of shock waves that affect cell viability. In vitro testing was conducted using the metastatic breast epithelial cell line MDA-MB-231. Shock waves were generated using a high-power pulse laser. Two different coating materials and different laser energy levels were used to vary the peak pressure, decay time, and the strength of subsequent peaks of the shock waves. Within the testing capability of the current study, it is shown that shock waves with a higher impulse led to lower cell viability, a higher detached cell ratio, and a higher cell death ratio, while shock waves with the same peak pressure could lead to different levels of cell damage. The results also showed that the detached cells had a higher cell death ratio compared to the attached cells. Moreover, a critical shock impulse of 5 Pa·s was found to cause the cell death ratio of the detached cells to exceed 50%. This work has demonstrated that, within the testing range shown here, the impulse, rather than the peak pressure, is the governing shock wave parameter for the damage of MDA-MB-231 breast cancer cells. The result suggests that a lower-pressure shock wave with a longer duration, or multiple sequential low amplitude shock waves can be applied over a duration shorter than the fundamental response period of the cells to achieve the same impact as shock waves with a high peak pressure but a short duration. The finding that cell viability is better correlated with shock impulse rather than peak pressure has potential significant implications on how shock waves should be tailored for cancer treatments, enhanced drug delivery, and diagnostic techniques to maximize efficacy while minimizing potential side effects.

Effect of geometrical parameters on the fluid dynamics of air-powered needle-free jet injectors

Needle-free jet injectors are non-invasive systems having intradermal drug delivery capabilities. At present, they revolutionize the next phase of drug delivery and therapeutic applications in the medical industry. An efficiently designed injection chamber can reduce the energy consumption required to achieve the maximum penetration depth in skin tissue. In this study, the authors explored the effect of various geometrical parameters using a computational fluid dynamics tool. Peak stagnation pressure during the initial phase of the injection procedure was considered as the quantifier for comparison because of its proportional relationship with the initial penetration depth during the injection process. Peak stagnation pressure indicates the maximum energy transformation that could happen between the microjet and skin tissues for an injection procedure. The results of this study indicated a tradeoff that exists between the attainable density and velocity of the microjet on the skin surface with variation in nozzle diameter; the optimum nozzle diameter was found to be within 200-250 μm under the present conditions. The authors also observed a discrepancy in the peak stagnation pressure value for lower filling ratios with variation in chamber diameter; hence, filling ratio of at least 50% was recommended for such systems. Furthermore, a 150% increase in the peak stagnation pressure was obtained with an angle of entry of 10°. In general, this study could provide valuable insights into the effect of geometrical parameters in the fluid dynamics characteristics of propelled microjets from the nozzle of a needle-free jet injector. Such information could be useful for the design of a mechanically driven needle-free jet injector having limited control over the energizing mechanism.

Picosecond-resolution phase-sensitive imaging of transparent objects in a single shot

With the growing interest in the optical imaging of ultrafast phenomena in transparent objects, from shock wave to neuronal action potentials, high contrast imaging at high frame rates has become desirable. While phase sensitivity provides the contrast, the frame rates and sequence depths are highly limited by the detectors. Here, we present phase-sensitive compressed ultrafast photography (pCUP) for single-shot real-time ultrafast imaging of transparent objects by combining the contrast of dark-field imaging with the speed and the sequence depth of CUP. By imaging the optical Kerr effect and shock wave propagation, we demonstrate that pCUP can image light-speed phase signals in a single shot with up to 350 frames captured at up to 1 trillion frames per second. We expect pCUP to be broadly used for a vast range of fundamental and applied sciences.

Survival of Extremotolerant Bacteria from the Mukundpura Meteorite Impact Crater

Carbonaceous meteorites provide clues with regard to prebiotic chemistry and the origin of life. Geological Survey of India recorded a carbonaceous chondrite meteorite fall in Mukundpura, India, on June 6, 2017. We conducted a study to investigate the microbial community that survived the meteorite impact. 16S rRNA metagenomic sequencing indicates the presence of Actinobacteria, Proteobacteria, and Acidobacteria in meteorite impact soil. Comparative phylogenetic analysis revealed an intriguing abundance of class Bacilli in the impact soil. Bacillus thermocopriae IR-1, a moderately thermotolerant organism, was isolated from a rock, impacted by the Mukundpura meteorite. We investigated the resilience of B. thermocopriae IR-1 to environmental stresses and impact shock in a Reddy shock tube. Bacillus thermocopriae IR-1 survived (28.82% survival) the effect of shock waves at a peak shock pressure of 300 kPa, temperature 400 K, and Mach number of 1.47. This investigation presents the first report on the effect of impact shock on B. thermocopriae IR-1. The study is also the first report on studying the microbial diversity and isolation of bacteria from impact crater soil immediately after meteorite impact event.

Stimulation of angiogenesis using single-pulse low-pressure shock wave treatment

Endothelial cells respond to mechanical stimuli such as stretch. This property can be exploited with caution to induce angiogenesis which will have immense potential to treat pathological conditions associated with insufficient angiogenesis. The primary aim of this study is to test if low-pressure shock waves can be used to induce angiogenesis. Using a simple diaphragm-based shock tube, we demonstrate that a single pulse of low pressure (0.4 bar) shock wave is enough to induce proliferation in bovine aortic endothelial cells and human pulmonary microvascular endothelial cells. We show that this is associated with enhanced Ca⁺⁺ influx and phosphorylation of phosphatidylinositol-3-kinase (PI3K) which is normally observed when endothelial cells are exposed to stretch. We also demonstrate the pro-angiogenic effect of shock waves of single pulse (per dose) using murine back punch wound model. Shock wave treated mice showed enhanced wound-induced angiogenesis as reflected by increased vascular area and vessel length. They also showed accelerated wound closure compared to control mice. Overall, our study shows that just a single pulse/shot (per dose) of shock waves can be used to induce angiogenesis. Importantly, we demonstrate this effect using a pulse of low-pressure shock waves (0.4 bar, in vitro and 0.15 bar, in vivo). KEY MESSAGES: Low-pressure single-pulse shock waves can induce endothelial cell migration and proliferation. This effect is endothelial cell specific. These shock waves enhance wound-induced angiogenesis in vivo. These shock waves can also accelerate wound healing in vivo.

Enhancement of the Effectiveness of Extracorporeal Shock Wave Therapy with Topical Corticosteroid in Treatment of Chronic Plantar Fasciitis: A Randomized Control Clinical Trial

BACKGROUND

Chronic recalcitrant plantar fasciitis is a disabling condition. We presumed if shock wave could increase the permeability of skin and facilitate penetration of topical corticosteroid through the skin; the combinational therapeutic effect would be stronger than using shock wave alone. The study purpose was to utilize the synergistic effect of shock wave and topical corticosteroid in treatment of plantar fasciitis.

MATERIALS AND METHODS

Patients in both groups (n = 40) received four sessions of shock wave with the same protocol at weekly intervals. At 30 min before each session, we used an occlusive dressing of topical clobetasol for the intervention group and Vaseline oil for the control group. Pain severity was assessed with visual analog scale (VAS) and modified Roles and Maudsley score (RMS) at baseline and 1 month and 3 months after intervention. Plantar fascia (PF) thickness was measured with ultrasonography at baseline and 3 months after intervention.

RESULTS

One month after intervention, VAS morning showed significant improvement in intervention group (P = 0.006) and RMS showed better improvement in intervention group (P = 0.026). There was no significant difference between the two groups after 3 months in RMS or VAS score. PF thickness was decreased significantly in both groups, but it was not significant between the two groups (P = 0.292).

CONCLUSIONS

This combinational therapy yielded earlier pain reduction and functional improvement than using shock wave alone; topical corticosteroid could enhance the effectiveness of shockwave in short-term in the treatment of recalcitrant plantar fasciitis.

Shock wave-induced permeabilization of mammalian cells

Controlled permeabilization of mammalian cell membranes is fundamental to develop gene and cell therapies based on macromolecular cargo delivery, a process that emerged against an increasing number of health afflictions, including genetic disorders, cancer and infections. Viral vectors have been successfully used for macromolecular delivery; however, they may have unpredictable side effects and have been limited to life-threatening cases. Thus, several chemical and physical methods have been explored to introduce drugs, vaccines, and nucleic acids into cells. One of the most appealing physical methods to deliver genes into cells is shock wave-induced poration. High-speed microjets of fluid, emitted due to the collapse of microbubbles after shock wave passage, represent the most significant mechanism that contributes to cell membrane poration by this technique. Herein, progress in shock wave-induced permeabilization of mammalian cells is presented. After covering the main concepts related to molecular strategies whose applications depend on safer drug delivery methods, the physics behind shock wave phenomena is described. Insights into the use of shock waves for cell membrane permeation are discussed, along with an overview of the two major biomedical applications thereof-i.e., genetic modification and anti-cancer shock wave-assisted chemotherapy. The aim of this review is to summarize 30 years of data showing underwater shock waves as a safe, noninvasive method for macromolecular delivery into mammalian cells, encouraging the development of further research, which is still required before the introduction of this promising tool into clinical practice.

Insights into the mechanism of a novel shockwave-assisted needle-free drug delivery device driven by in situ-generated oxyhydrogen mixture which provides efficient protection against mycobacterial infections

Background

Needle-free, painless and localized drug delivery has been a coveted technology in the area of biomedical research. We present an innovative way of trans-dermal vaccine delivery using a miniature detonation-driven shock tube device. This device utilizes~2.5 bar of in situ generated oxyhydrogen mixture to produce a strong shockwave that accelerates liquid jets to velocities of about 94 m/s.

Method

Oxyhydrogen driven shock tube was optimized for efficiently delivering vaccines in the intradermal region in vivo. Efficiency of vaccination was evaluated by pathogen challenge and host immune response. Expression levels of molecular markers were checked by qRT-PCR.

Results

High efficiency vaccination was achieved using the device. Post pathogen challenge with Mycobacterium tuberculosis, 100% survival was observed in vaccinated animals. Immune response to vaccination was significantly higher in the animals vaccinated using the device as compared to conventional route of vaccination.

Conclusion

A novel device was developed and optimized for intra dermal vaccine delivery in murine model. Conventional as well in-house developed vaccine strains were used to test the system. It was found that the vaccine delivery and immune response was at par with the conventional routes of vaccination. Thus, the device reported can be used for delivering live attenuated vaccines in the future.

Mechanism of transformation in Mycobacteria using a novel shockwave assisted technique driven by in-situ generated oxyhydrogen

We present a novel method for shockwave-assisted bacterial transformation using a miniature oxyhydrogen detonation-driven shock tube. We have obtained transformation efficiencies of about 1.28 × 10⁶, 1.7 × 10⁶, 5 × 10⁶, 1 × 10⁵, 1 × 10⁵ and 2 × 10⁵ transformants/µg of DNA for Escherichia coli, Salmonella Typhimurum, Pseudomonas aeruginosa, Mycobacterium smegmatis, Mycobacterium tuberculosis (Mtb) and Helicobacter pylori respectively using this method which are significantly higher than those obtained using conventional methods. Mtb is the most difficult bacteria to be transformed and hence their genetic modification is hampered due to their poor transformation efficiency. Experimental results show that longer steady time duration of the shockwave results in higher transformation efficiencies. Measurements of Young's modulus and rigidity of cell wall give a good understanding of the transformation mechanism and these results have been validated computationally. We describe the development of a novel shockwave device for efficient bacterial transformation in complex bacteria along with experimental evidence for understanding the transformation mechanism.

Optimization of a Diaphragm for a Micro-Shock Tube-Based Drug Delivery Method

This paper presents the design optimization of diaphragms for a micro-shock tube-based drug delivery device. The function of the diaphragm is to impart the required velocity and direction to the loosely held drug particles on the diaphragm through van der Waals interaction. The finite element model-based studies involved diaphragms made up of copper, brass and aluminium. The study of the influence of material and geometric parameters serves as a vital tool in optimizing the magnitude and direction of velocity distribution on the diaphragm surface. Experiments carried out using a micro-shock tube validate the final deformed shape of the diaphragms determined from the finite element simulation. The diaphragm yields a maximum velocity of 335 m/s for which the maximum deviation of the velocity vector is 0.62°. Drug particles that travel to the destination target tissue are simulated using the estimated velocity distribution and angular deviation. Further, a theoretical model of penetration helps in the prediction of the drug particle penetration in the skin tissue like a target, which is found to be 0.126 mm. The design and calibration procedure of a micro-shock tube device to alter drug particle penetration considering the skin thickness and property are presented.

Development of a novel miniature detonation-driven shock tube assembly that uses in situ generated oxyhydrogen mixture

A novel concept to generate miniature shockwaves in a safe, repeatable, and controllable manner in laboratory confinements using an in situ oxyhydrogen generator has been proposed and demonstrated. This method proves to be more advantageous than existing methods because there is flexibility to vary strength of the shockwave, there is no need for storage of high pressure gases, and there is minimal waste disposal. The required amount of oxyhydrogen mixture is generated using alkaline electrolysis that produces hydrogen and oxygen gases in stoichiometric quantity. The rate of oxyhydrogen mixture production for the newly designed oxyhydrogen generator is found to be around 8 ml/s experimentally. The oxyhydrogen generator is connected to the driver section of a specially designed 10 mm square miniature shock tube assembly. A numerical code that uses CANTERA software package is used to predict the properties of the driver gas in the miniature shock tube. This prediction along with the 1-D shock tube theory is used to calculate the properties of the generated shockwave and matches reasonably well with the experimentally obtained values for oxyhydrogen mixture fill pressures less than 2.5 bars. The miniature shock tube employs a modified tri-clover clamp assembly to facilitate quick changing of diaphragm and replaces the more cumbersome nut and bolt system of fastening components. The versatile nature of oxyhydrogen detonation-driven miniature shock tube opens up new horizons for shockwave-assisted interdisciplinary applications.

Enhancing the efficiency of desensitizing agents with shockwave treatment – a new paradigm in dentinal hypersensitivity management

Micro-shockwave assisted dentin hypersensitivity management.

Successful treatment of biofilm infections using shock waves combined with antibiotic therapy

Many bacteria secrete a highly hydrated framework of extracellular polymer matrix on suitable substrates and embed within the matrix to form a biofilm. Bacterial biofilms are observed on many medical devices, endocarditis, periodontitis and lung infections in cystic fibrosis patients. Bacteria in biofilm are protected from antibiotics and >1,000 times of the minimum inhibitory concentration may be required to treat biofilm infections. Here, we demonstrated that shock waves could be used to remove Salmonella, Pseudomonas and Staphylococcus biofilms in urinary catheters. The studies were extended to a Pseudomonas chronic pneumonia lung infection and Staphylococcus skin suture infection model in mice. The biofilm infections in mice, treated with shock waves became susceptible to antibiotics, unlike untreated biofilms. Mice exposed to shock waves responded to ciprofloxacin treatment, while ciprofloxacin alone was ineffective in treating the infection. These results demonstrate for the first time that, shock waves, combined with antibiotic treatment can be used to treat biofilm infection on medical devices as well as in situ infections.

Needle free injection technology: A complete insight

Needle free injection technology (NFIT)is an extremely broad concept which include a wide range of drug delivery systems that drive drugs through the skin using any of the forces as Lorentz, Shock waves, pressure by gas or electrophoresis which propels the drug through the skin, virtually nullifying the use of hypodermic needle. This technology is not only touted to be beneficial for the pharma industry but developing world too find it highly useful in mass immunization programmes, bypassing the chances of needle stick injuries and avoiding other complications including those arising due to multiple use of single needle. The NFIT devices can be classified based on their working, type of load, mechanism of drug delivery and site of delivery. To administer a stable, safe and an effective dose through NFIT, the sterility, shelf life and viscosity of drug are the main components which should be taken care of. Technically superior needle-free injection systems are able to administer highly viscous drug products which cannot be administered by traditional needle and syringe systems, further adding to the usefulness of the technology. NFIT devices can be manufactured in a variety of ways; however the widely employed procedure to manufacture it is by injection molding technique. There are many variants of this technology which are being marketed, such as Bioject(®) ZetaJetTM, Vitajet 3, Tev-Tropin(®) and so on. Larger investment has been made in developing this technology with several devices already being available in the market post FDA clearance and a great market worldwide.

Remotely triggered micro-shock wave responsive drug delivery system for resolving diabetic wound infection and controlling blood sugar levels

A novel, micro-shock wave responsive spermidine and dextran sulfate microparticle was developed.

Next generation intra- and transdermal therapeutic systems: using non- and minimally-invasive technologies to increase drug delivery into and across the skin

The number of drug molecules approved by the regulatory authorities for transdermal administration is relatively modest - less than two dozen. Many other therapies might benefit from the advantages offered by the transdermal route. That they have not already done so is due to the exceptional efficacy of the stratum corneum as a diffusional barrier and its remarkable ability to restrict molecular transport. As a result only extremely potent therapeutics possessing the necessary physicochemical properties can be delivered by passive diffusion across intact skin at pharmacologically relevent rates. This has led to the development of several delivery technologies that might be used to expand the range of medicinal agents that can be administered transdermally with the requisite delivery kinetics. There are essentially two approaches: (i) provide an improved driving force to increase the rate of transport (i.e., act on the molecule) or (ii) modify the properties of the microenvironment through which diffusion must occur (i.e., act on the stratum corneum). The challenge for the latter approach is to compromise the barrier in a reversible and relatively painless manner that minimises irritation, is practical for chronic conditions and has minimal risk of infection. Here, we review some of the physical methods that have been used to either transiently perturb the skin barrier or to provide additional driving forces to facilitate molecular transport with a particular focus on technologies that have either led to marketed products or have at least reached the clinical development stage.