Hollow Mesoporous Silica@Zeolitic Imidazolate Framework Capsules and Their Applications for Gentamicin Delivery

Ultrasound-Triggered NO Release to Promote Axonal Regeneration for Noise-Induced Hearing Loss Therapy

Intense noise poses a threat to spiral ganglion neurons (SGNs) in the inner ear, often resulting in limited axonal regeneration during noise injury and leading to noise-induced hearing loss (NIHL). Here, we propose an ultrasound-triggered nitric oxide (NO) release to enhance the sprouting and regeneration of injured axons in SGNs. We developed hollow silicon nanoparticles to load nitrosylated N-acetylcysteine, producing HMSN-SNO, which effectively protects NO from external interferences. Utilizing low-intensity ultrasound stimulation with bone penetration, we achieve the controlled release of NO from HMSN-SNO within the cochlea. In mice with NIHL, a rapid and extensive loss of synaptic connections between hair cells and SGNs is observed within 24 h after exposure to excessive noise. However, this loss could be reversed with the combined treatment, resulting in a hearing functional recovery from 83.57 to 65.00 dB SPL. This positive outcome is attributed to the multifunctional effects of HMSN-SNO, wherein they scavenge reactive oxygen species (ROS) to reverse the pathological microenvironment and simultaneously upregulate the CREB/BDNF/EGR1 signaling pathway, thereby enhancing neuroplasticity and promoting the regeneration of neuronal axons. These findings underscore the potential of nanomedicine for neuroplasticity modulation, which holds promise for advancing both basic research and the further treatment of neurological diseases.

Potential nanotechnology-based diagnostic and therapeutic approaches for Meniere's disease

Meniere's disease (MD) is a progressive inner ear disorder involving recurrent and prolonged episodes or attacks of vertigo with associated symptoms, resulting in a significantly reduced quality of life for sufferers. In most cases, MD starts in one ear; however, in one-third of patients, the disorder progresses to the other ear. Unfortunately, the etiology of the disease is unknown, making the development of effective treatments difficult. Nanomaterials, including nanoparticles (NPs) and nanocarriers, offer an array of novel diagnostic and therapeutic applications related to MD. NPs have specific features such as biocompatibility, biochemical stability, targetability, and enhanced visualization using imaging tools. This paper provides a comprehensive and critical review of recent advancements in nanotechnology-based diagnostic and therapeutic approaches for MD. Furthermore, the crucial challenges adversely affecting the use of nanoparticles to treat middle ear disorders are investigated. Finally, this paper provides recommendations and future directions for improving the performances of nanomaterials on theragnostic applications of MD.

Application of Nanomedicine in Inner Ear Diseases

The treatment of inner ear disorders always remains a challenge for researchers. The presence of various physiological barriers, primarily the blood–labyrinth barrier (BLB), limits the accessibility of the inner ear and hinders the efficacy of various drug therapies. Yet despite recent advances in the cochlea for repair and regeneration, there are currently no pharmacological or biological interventions for hearing loss. Current research focuses on the localized drug-, gene-, and cell-based therapies. Drug delivery based on nanotechnology represents an innovative strategy to improve inner ear treatments. Materials with specific nanostructures not only exhibit a unique ability to encapsulate and transport therapeutics to the inner ear but also endow specific targeting properties to auditory hair cells as well as the stabilization and sustained drug release. Along with this, some alternative routes, like intratympanic drug delivery, can also offer a better means to access the inner ear without exposure to the BLB. This review discusses a variety of nano-based drug delivery systems to the ear for treating inner ear diseases. The main factors affecting the curative efficacy of nanomaterials are also discussed. With a deeper understanding of the link between these crucial factors and the clinical effect of nanomaterials, it paves the way for the optimization of the therapeutic activity of nanocarriers.

Evolution of drug-eluting biomedical implants for sustained drug delivery

In the field of drug delivery, the most commonly used treatments have traditionally been systemically delivered using oral or intravenous administration. The problems associated with this type of delivery is that the drug concentration is controlled by first pass metabolism, and therefore may not always remain within the therapeutic window. Implantable drug delivery systems (IDDSs) are an excellent alternative to traditional delivery because they offer the ability to precisely control the drug release, deliver drugs locally to the target tissue, and avoid the toxic side effects often experienced with systemic administration. Since the creation of the first FDA-approved IDDS in 1990, there has been a surge in research devoted to fabricating and testing novel IDDS formulations. The versatility of these systems is evident when looking at the various biomedical applications that utilize IDDSs. This review provides an overview of the history of IDDSs, with examples of the different types of IDDS formulations, as well as looking at current and future biomedical applications for such systems. Though there are still obstacles that need to be overcome, ever-emerging new technologies are making the manufacturing of IDDSs a rewarding therapeutic endeavor with potential for further improvements.

The Progress and Prospect of Zeolitic Imidazolate Frameworks in Cancer Therapy, Antibacterial Activity, and Biomineralization

The progressive development of zeolitic imidazolate frameworks (ZIFs), as a subfamily of metal-organic frameworks (MOFs), and their unique features, including tunable pore size, large surface area, high thermal stability, and biodegradability/biocompatibility, have made them attractive in the field of biomedicine, especially for drug delivery and biomineralization applications. The high porosity of ZIFs gives them the opportunity for encapsulating a high amount of therapeutic drugs, proteins, imaging cargos, or a combination of them to construct advanced multifunctional drug delivery systems (DDSs) with combined therapeutic and imaging capabilities. This review summarizes recent strategies on the design and fabrication of ZIF-based nansystems and their exploration in the biomedical field. First, recent developments for the adjustment of particle size, functionality, and morphology of ZIFs are discussed, which are important for achieving optimized therapeutic/theranostic nanosystems. Second, recent trends on the application of ZIF nanocarriers for the loading of diverse cargos, including anticancer medicines, antibiotic drugs, enzymes, proteins, photosensitizers, as well as imaging and photothermal agents, are investigated in order to understand how multifunctional DDSs can be designed based on the ZIF nanoparticles to treat different diseases, such as cancer and infection. Finally, prospects on the future research direction and applications of ZIF-based nanomedicines are discussed.

Developments in Bio-Inspired Nanomaterials for Therapeutic Delivery to Treat Hearing Loss

Sensorineural hearing loss affects millions of people worldwide and is a growing concern in the aging population. Treatment using aminoglycoside antibiotics for infection and exposure to loud sounds contribute to the degeneration of cochlear hair cells and spiral ganglion neurons. Cell loss impacts cochlear function and causes hearing loss in ∼ 15% of adult Americans (∼36 million). The number of individuals with hearing loss will likely grow with increasing lifespans. Current prosthesis such as hearing aids and cochlear implants can ameliorate hearing loss. However, hearing aids are ineffective if hair cells or spiral ganglion neurons are severely damaged, and cochlear implants are ineffective without properly functioning spiral ganglion neurons. As such, strategies that alleviate hearing loss by preventing degeneration or promoting cell replacement are urgently needed. Despite showing great promise from in vitro studies, the complexity and delicate nature of the inner ear poses a huge challenge for delivering therapeutics. To mitigate risks and complications associated with surgery, new technologies and methodologies have emerged for efficient delivery of therapeutics. We will focus on biomaterials that allow controlled and local drug delivery into the inner ear. The rapid development of microsurgical techniques in conjunction with novel bio- and nanomaterials for sustained drug delivery appears bright for hearing loss treatment.