Fast Customization of Hollow Microneedle Patches for Insulin Delivery

Dissolving microneedles for transdermal drug delivery in cancer immunotherapy

Immunotherapy is an important approach in cancer treatment. Transdermal administration is emerging as a promising method for delivering immunotherapeutics. Dissolving microneedles are made mainly of soluble or biodegradable polymers and have garnered widespread attention due to their painlessness, safety, convenience, excellent drug loading capacity, and easy availability of various materials, making them an ideal transdermal delivery system. This review comprehensively summarized the preparation methods, materials, and applications of dissolving microneedles in cancer vaccines, immune checkpoint inhibitors, and adoptive cell therapy. Additionally, the challenges and perspectives associated with their future clinical translation are discussed.

Applications and prospects of microneedles in tumor drug delivery

As drug delivery devices, microneedles are used widely in the local administration of various drugs. Such drug-loaded microneedles are minimally invasive, almost painless, and have high drug delivery efficiency. In recent decades, with advancements in microneedle technology, an increasing number of adaptive, engineered, and intelligent microneedles have been designed to meet increasing clinical needs. This article summarizes the types, preparation materials, and preparation methods of microneedles, as well as the latest research progress in the application of microneedles in tumor drug delivery. This article also discusses the current challenges and improvement strategies in the use of microneedles for tumor drug delivery.

A Bibliometric Analysis of 3D Printing in Personalized Medicine Research from 2012 to 2022

In recent years, the 3D printing of personalized drug formulations has attracted the attention of medical practitioners and academics. However, there is a lack of data-based analyses on the hotspots and trends of research in this field. Therefore, in this study, we performed a bibliometric analysis to summarize the 3D printing research in the field of personalized drug formulation from 2012 to 2022. This study was based on the Web of Science Core Collection Database, and a total of 442 eligible publications were screened. Using VOSviewer and online websites for bibliometric analysis and scientific mapping, it was observed that annual publications have shown a significant growth trend over the last decade. The United Kingdom and the United States, which account for 45.5% of the total number of publications, are the main drivers of this field. The International Journal of Pharmaceutics and University College London are the most prolific and cited journals and institutions. The researchers with the most contributions are Basit, Abdul W. and Goyanes Alvaro. The keyword analysis concluded that the current research hotspots are "drug release" and "drug dosage forms". In conclusion, 3D printing has broad application prospects in the field of personalized drugs, which will bring the pharmaceutical industry into a new era of innovation.

Intelligent Insulin vs. Artificial Intelligence for Type 1 Diabetes: Will the Real Winner Please Stand Up?

Research in the treatment of type 1 diabetes has been addressed into two main areas: the development of "intelligent insulins" capable of auto-regulating their own levels according to glucose concentrations, or the exploitation of artificial intelligence (AI) and its learning capacity, to provide decision support systems to improve automated insulin therapy. This review aims to provide a synthetic overview of the current state of these two research areas, providing an outline of the latest development in the search for "intelligent insulins," and the results of new and promising advances in the use of artificial intelligence to regulate automated insulin infusion and glucose control. The future of insulin treatment in type 1 diabetes appears promising with AI, with research nearly reaching the possibility of finally having a "closed-loop" artificial pancreas.

Customized flexible hollow microneedles for psoriasis treatment with reduced-dose drug

Microneedles, especially hollow microneedles (HMNs), play an important role in drug delivery, but most of the current HMNs are manufactured based on silicon microfabrication (lithography, etching, etc.), which are slightly conservative due to the lack of low-cost, batch-scale and customized preparation approach, especially for the HMNs with flexible substrate. For the first time, we propose the use of a high-precision 3D printed master mold followed by a dual-molding process for the preparation of HMNs with different shapes, heights, and inner and outer diameters to satisfy different drug delivery needs. The 3D printed master mold and negative mold can be reused, thereby significantly reducing the cost. HMNs are based on biocompatible materials, such as heat-curing polymers or light-curing resins. The thickness and rigidity/flexibility characteristics of the substrate can be customized for different applications. The drug delivery efficiency of the fabricated HMNs was verified by the in situ treatment of psoriasis on the backs of mice, which required only a 0.1-fold oral dose to achieve similar efficacy, and the associated side effects and drug toxicity were reduced. Thus, this dual-molding process can reinvigorate HMNs development.

3D-Printed Microinjection Needle Arrays via a Hybrid DLP-Direct Laser Writing Strategy

Microinjection protocols are ubiquitous throughout biomedical fields, with hollow microneedle arrays (MNAs) offering distinctive benefits in both research and clinical settings. Unfortunately, manufacturing-associated barriers remain a critical impediment to emerging applications that demand high-density arrays of hollow, high-aspect-ratio microneedles. To address such challenges, here, a hybrid additive manufacturing approach that combines digital light processing (DLP) 3D printing with "ex situ direct laser writing (esDLW)" is presented to enable new classes of MNAs for fluidic microinjections. Experimental results for esDLW-based 3D printing of arrays of high-aspect-ratio microneedles-with 30 μm inner diameters, 50 μm outer diameters, and 550 μm heights, and arrayed with 100 μm needle-to-needle spacing-directly onto DLP-printed capillaries reveal uncompromised fluidic integrity at the MNA-capillary interface during microfluidic cyclic burst-pressure testing for input pressures in excess of 250 kPa (n = 100 cycles). Ex vivo experiments perform using excised mouse brains reveal that the MNAs not only physically withstand penetration into and retraction from brain tissue but also yield effective and distributed microinjection of surrogate fluids and nanoparticle suspensions directly into the brains. In combination, the results suggest that the presented strategy for fabricating high-aspect-ratio, high-density, hollow MNAs could hold unique promise for biomedical microinjection applications.

Microneedles: structure, classification, and application in oral cancer theranostics

Oral cancer is a malignant tumor that threatens the health of individuals on a global scale. Currently available clinical treatment methods, including surgery, radiotherapy, and chemotherapy, significantly impact the quality of life of patients with systemic side effects. In the treatment of oral cancer, local and efficient delivery of antineoplastic drugs or other substances (like photosensitizers) to improve the therapy effect is a potential way to optimize oral cancer treatments. As an emerging drug delivery system in recent years, microneedles (MNs) can be used for local drug delivery, offering the advantages of high efficiency, convenience, and noninvasiveness. This review briefly introduces the structures and characteristics of various types of MNs and summarizes MN preparation methods. An overview of the current research application of MNs in different cancer treatments is provided. Overall, MNs, as a means of transporting substances, demonstrate great potential in oral cancer treatments, and their promising future applications and perspectives of MNs are outlined in this review.

3D printing of microneedle arrays for hair regeneration in a controllable region

Hair loss is a common skin disease that causes intense emotional suffering. Hair regeneration in a personalized area is highly desirable for patients with different balding conditions. However, the existing pharmaceutical treatments have difficulty precisely regenerating hair in a desired area. Here, we show a method to precisely control the hair regeneration using customized microneedle arrays (MNAs). The MNA with a customized shape is fast fabricated by a static optical projection lithography process in seconds, which is a 3D printing technology developed by our group. In the mouse model, MNA treatment could induce hair regrowth in a defined area corresponding to the customized shape of MNA. And the regenerated hair promoted by MNAs had improved quality. Cellular and molecular analysis indicated that MNA treatment could recruit macrophages in situ and then initiate the proliferation of hair follicle stem cells, thereby improving hair regeneration. Meanwhile, the activation of the Wnt/β-catenin signaling pathway was observed in hair follicles. The expressions of Hgf, Igf 1 and Tnf-α were also upregulated in the treated skin, which may also be beneficial for the MNA-induced hair regeneration. This study provides a strategy to precisely control hair regeneration using customized microneedle arrays by recruiting macrophages in situ, which holds the promise for the personalized treatment of hair loss.

3D-printed microneedle arrays for drug delivery

Microneedle arrays provide an efficient tool for transdermal drug delivery in a minimally invasive and painless manner, showing great potential applications in medicine. However, it remains challenging to fabricate the desired microneedle arrays, because of their micron-scale size and fine structure. Novel manufacturing technologies are very wanted for the development of microneedle arrays, which would solidly advance the clinical translation of microneedle arrays. 3D printing technology is a powerful manufacturing technology with superiority in fabricating personalized and complex structures. Currently, 3D printing technology has been employed to fabricate microneedle arrays, which could push more microneedle arrays into clinic and inspire the development of future microneedle arrays. This work reviews the art of 3D printing microneedle arrays, the benefits of fabricating microneedle arrays with 3D printing, and the considerations for clinical translation of 3D-printed microneedle arrays. This work provides an overview of the current 3D-printed microneedle arrays in drug delivery.