Nebulization of siRNA for inhalation therapy based on a microfluidic surface acoustic wave platform

A narrative review: Ultrasound-Assisted drug delivery: Improving treatments via multiple mechanisms

Safe and efficient drug delivery is as important as drug development. Biological barriers, such as cell membranes, present significant challenges in drug delivery, especially for newly developed protein-, nucleic acid-, and cell-based drugs. Ultrasound-mediated drug delivery systems offer a promising strategy to overcome these challenges. Ultrasound, a mechanical wave with energy, produces thermal effects, cavitation, acoustic radiation, and other biophysical effects. Used alone or in combination with microbubbles or sonosensitizers, it breaks biological barriers, enhances targeted drug delivery, reduces adverse reactions, controls drug release, switches on/off drug functions, and ultimately improves therapeutic efficiency. Various ultrasound-mediated drug delivery methods, including transdermal drug delivery, nebulization, targeted microbubble destruction, and sonodynamic therapy, are being actively explored for the treatment of various diseases. This review article introduces the principles, advantages, and applications of ultrasound-mediated drug delivery methods for improved therapeutic outcomes and discusses future prospects in this field.

Breath and Beyond: Advances in Nanomedicine for Oral and Intranasal Aerosol Drug Delivery

Designing and standardizing drug formulations are crucial for ensuring the safety and efficacy of medications. Nanomedicine utilizes nano drug delivery systems and advanced nanodevices to address numerous critical medical challenges. Currently, oral and intranasal aerosol drug delivery (OIADD) is the primary method for treating respiratory diseases worldwide. With advancements in disease understanding and the development of aerosolized nano drug delivery systems, the application of OIADD has exceeded its traditional boundaries, demonstrating significant potential in the treatment of non-respiratory conditions as well. This study provides a comprehensive overview of the applications of oral and intranasal aerosol formulations in disease treatment. It examines the key challenges limiting the development of nanomedicines in drug delivery systems, formulation processes, and aerosol devices and explores the latest advancements in these areas. This review aims to offer valuable insights to researchers involved in the development of aerosol delivery platforms.

Acoustofluidic Diversity Achieved by Multiple Modes of Acoustic Waves Generated on Piezoelectric-Film-Coated Aluminum Sheets

Excitation of multiple acoustic wave modes on a single chip is beneficial to implement diversified acoustofluidic functions. Conventional acoustic wave devices made of bulk LiNbO3 substrates generally generate few acoustic wave modes once the crystal-cut and electrode pattern are defined, limiting the realization of acoustofluidic diversity. In this paper, we demonstrated diversity of acoustofluidic behaviors using multiple modes of acoustic waves generated on piezoelectric-thin-film-coated aluminum sheets. Multiple acoustic wave modes were excited by varying the ratios between IDT pitch/wavelength and substrate thickness. Through systematic investigation of fluidic actuation behaviors and performances using these acoustic wave modes, we demonstrated fluidic actuation diversities using various acoustic wave modes and showed that the Rayleigh mode, pseudo-Rayleigh mode, and A0 mode of Lamb wave generally have better fluidic actuation performance than those of Sezawa mode and higher-order modes of Lamb wave, providing guidance for high-performance acoustofluidic actuation platform design. Additionally, we demonstrated diversified particle patterning functions, either on two sides of acoustic wave device or on a glass sheet by coupling acoustic waves into the glass using the gel. The pattern formation mechanisms were investigated through finite element simulations of acoustic pressure fields under different experimental configurations.

Aerosol Inhalation of Gene Delivery Therapy for Pulmonary Diseases

Gene delivery therapy has emerged as a popular approach for the treatment of various diseases. However, it still poses the challenges of accumulation in target sites and reducing off-target effects. Aerosol gene delivery for the treatment of pulmonary diseases has the advantages of high lung accumulation, specific targeting and fewer systemic side effects. However, the key challenge is selecting the appropriate formulation for aerosol gene delivery that can overcome physiological barriers. There are numerous existing gene carriers under study, including viral vectors and non-viral vectors. With the development of biomaterials, more biocompatible substances have applied gene delivery via inhalation. Furthermore, many types of genes can be delivered through aerosol inhalation, such as DNA, mRNA, siRNA and CRISPR/Cas9. Aerosol delivery of different types of genes has proven to be efficient in the treatment of many diseases such as SARS-CoV-2, cystic fibrosis and lung cancer. In this paper, we provide a comprehensive review of the ongoing research on aerosol gene delivery therapy, including the basic respiratory system, different types of gene carriers, different types of carried genes and clinical applications.

Acoustothermal transfection for cell therapy

Transfected stem cells and T cells are promising in personalized cell therapy and immunotherapy against various diseases. However, existing transfection techniques face a fundamental trade-off between transfection efficiency and cell viability; achieving both simultaneously remains a substantial challenge. This study presents an acoustothermal transfection method that leverages acoustic and thermal effects on cells to enhance the permeability of both the cell membrane and nuclear envelope to achieve safe, efficient, and high-throughput transfection of primary T cells and stem cells. With this method, two types of plasmids were simultaneously delivered into the nuclei of mesenchymal stem cells (MSCs) with efficiencies of 89.6 ± 1.2%. CXCR4-transfected MSCs could efficiently target cerebral ischemia sites in vivo and reduce the infarct volume in mice. Our acoustothermal transfection method addresses a key bottleneck in balancing the transfection efficiency and cell viability, which can become a powerful tool in the future for cellular and gene therapies.

Nebulised delivery of RNA formulations to the lungs: From aerosol to cytosol

In the past decade RNA-based therapies such as small interfering RNA (siRNA) and messenger RNA (mRNA) have emerged as new and ground-breaking therapeutic agents for the treatment and prevention of many conditions from viral infection to cancer. Most clinically approved RNA therapies are parenterally administered which impacts patient compliance and adds to healthcare costs. Pulmonary administration via inhalation is a non-invasive means to deliver RNA and offers an attractive alternative to injection. Nebulisation is a particularly appealing method due to the capacity to deliver large RNA doses during tidal breathing. In this review, we discuss the unique physiological barriers presented by the lung to efficient nebulised RNA delivery and approaches adopted to circumvent this problem. Additionally, the different types of nebulisers are evaluated from the perspective of their suitability for RNA delivery. Furthermore, we discuss recent preclinical studies involving nebulisation of RNA and analysis in in vitro and in vivo settings. Several studies have also demonstrated the importance of an effective delivery vector in RNA nebulisation therefore we assess the variety of lipid, polymeric and hybrid-based delivery systems utilised to date. We also consider the outlook for nebulised RNA medicinal products and the hurdles which must be overcome for successful clinical translation. In summary, nebulised RNA delivery has demonstrated promising potential for the treatment of several lung-related conditions such as asthma, COPD and cystic fibrosis, to which the mode of delivery is of crucial importance for clinical success.

Acoustofluidics for simultaneous droplet transport and centrifugation facilitating ultrasensitive biomarker detection

Trace biological sample detection is critical for the analysis of pathologies in biomedicine. Integration of microfluidic manipulation techniques typically strengthens biosensing performance. For instance, using isothermal amplification reactions to sense trace miRNA in peripheral circulation lacks a sufficiently complex pretreatment process that limits the sensitivity of on-chip detection. Herein we propose an orthogonal tunable acoustic tweezer (OTAT) to simultaneously actuate the transportation and centrifugation of μ-droplets on a single device. The OTAT enables diversified modes of droplet transportation such as unidirectional transport, multi-direction transport, round-trip transport, tilt angle movement, multi-droplet fusion, and continuous centrifugation of the dynamic droplets simultaneously. The multiplicity of modalities enables the focusing of a loaded analyte at the center of the droplet or constant rotation about the center axis of the droplet. We herein demonstrate the OTAT's ability to actuate transportation, fusion, and centrifugation-based pretreatment of two biological sample droplets loaded with miRNA biomarkers and multiple mixtures, as well as facilitating the increase of fluorescence detection sensitivity by an order of magnitude compared to traditional tube reaction methods. The results herein demonstrate the OTAT-based droplet acoustofluidic platform's ability to combine a wide range of biosensing mechanisms and provide a higher accuracy of detection for one-stop point-of-care disease diagnosis.

Acoustic resonance effects and cavitation in SAW aerosol generation

The interaction of surface acoustic waves (SAWs) with liquids enables the production of aerosols with adjustable droplet sizes in the micrometer range expelled from a very compact source. Understanding the nonlinear acousto-hydrodynamics of SAWs with a regulated micro-scale liquid film is essential for acousto-microfluidics platforms, particularly aerosol generators. In this study, we demonstrate the presence of micro-cavitation in a MHz-frequency SAW aerosol generation platform, which is touted as a leap in aerosol technology with versatile application fields including biomolecule inhalation therapy, micro-chromatography and spectroscopy, olfactory displays, and material deposition. Using analysis methods with high temporal and spatial resolution, we demonstrate that SAWs stabilize spatially arranged liquid micro-domes atop the generator's surface. Our experiments show that these liquid domes become acoustic resonators with highly fluctuating pressure amplitudes that can even nucleate cavitation bubbles, as supported by analytical modeling. The observed fragmentation of liquid domes indicates the participation of three droplet generation mechanisms, including cavitation and capillary-wave instabilities. During aerosol generation, the cavitation bubbles contribute to the ejection of droplets from the liquid domes and also explain observed microstructural damage patterns on the chip surface eventually caused by cavitation-based erosion.

Inhalation delivery of nucleic acid gene therapies in preclinical drug development

INTRODUCTION

Inhaled gene therapy programs targeting diseases of the lung have seen increasing interest in recent years, though as of yet no product has successfully entered the market. Preclinical research to support such programs is critically important in maximizing the chances of developing successful candidates.

AREAS COVERED

Aspects of inhalation delivery of gene therapies are reviewed, with a focus on preclinical research in animal models. Various barriers to inhalation delivery of gene therapies are discussed, including aerosolization stresses, aerosol behavior in the respiratory tract, and disposition processes post-deposition. Important aspects of animal models are considered, including determinations of biologically relevant determinations of dose and issues related to translatability.

EXPERT OPINION

Development of clinically-efficacious inhaled gene therapies has proven difficult owing to numerous challenges. Fit-for-purpose experimental and analytical methods are necessary for determinations of biologically relevant doses in preclinical animal models. Further developments in disease-specific animal models may aid in improving the translatability of results in future work, and we expect to see accelerated interests in inhalation gene therapies for various diseases. Sponsors, researchers, and regulators are encouraged to engage in early and frequent discussion regarding candidate therapies, and additional dissemination of preclinical methodologies would be of immense value in avoiding common pitfalls.

Advances in soft mist inhalers

INTRODUCTION

Soft mist inhalers (SMIs) are propellant-free inhalers that utilize mechanical power to deliver single or multiple doses of inhalable drug aerosols in the form of a slow mist to patients. Compared to traditional inhalers, SMIs allow for a longer and slower release of aerosol with a smaller ballistic effect, leading to a limited loss in the oropharyngeal area, whilst requiring little coordination of actuation and inhalation by patients. Currently, the Respimat® is the only commercially available SMI, with several others in different stages of preclinical and clinical development.

AREAS COVERED

The primary purpose of this review is to critically assess recent advances in SMIs for the delivery of inhaled therapeutics.

EXPERT OPINION

Advanced particle formulations, such as nanoparticles which target specific areas of the lung, Biologics, such as vaccines, proteins, and antibodies (which are sensitive to aerosolization), are expected to be generally delivered by SMIs. Furthermore, repurposed drugs are expected to constitute a large share of future formulations to be delivered by SMIs. SMIs can also be employed for the delivery of formulations that target systemic diseases. Finally, digitalizing SMIs would improve patient adherence and provide clinicians with fundamental insights into patients' treatment progress.

siRNA-Mediated Timp1 Silencing Inhibited the Inflammatory Phenotype during Acute Lung Injury

Acute lung injury is a complex cascade process that develops in response to various damaging factors, which can lead to acute respiratory distress syndrome. Within this study, based on bioinformatics reanalysis of available full-transcriptome data of acute lung injury induced in mice and humans by various factors, we selected a set of genes that could serve as good targets for suppressing inflammation in the lung tissue, evaluated their expression in the cells of different origins during LPS-induced inflammation, and chose the tissue inhibitor of metalloproteinase Timp1 as a promising target for suppressing inflammation. We designed an effective chemically modified anti-TIMP1 siRNA and showed that Timp1 silencing correlates with a decrease in the pro-inflammatory cytokine IL6 secretion in cultured macrophage cells and reduces the severity of LPS-induced acute lung injury in a mouse model.